Soft drinks are enormously popular beverages consisting primarily of carbonated water, sugar, and flavorings. Nearly 200 nations enjoy the sweet, sparkling soda with an annual consumption of more than 34 billion gallons. Soft drinks rank as America's favorite beverage segment, representing 25% of the total beverage market. In the early 1990s per capita consumption of soft drinks in the U.S. was 49 gallons, 15 gallons more than the next most popular beverage, water.

Raw Materials
Carbonated water constitutes up to 94% of a soft drink. Carbon dioxide adds that special sparkle and bite to the beverage and also acts as a mild preservative. Carbon dioxide is an uniquely suitable gas for soft drinks because it is inert, non-toxic, and relatively inexpensive and easy to liquefy.

The second main ingredient is sugar, which makes up 7-12% of a soft drink. Used in either dry or liquid form, sugar adds sweetness and body to the beverage, enhancing the "mouth-feel," an important component for consumer enjoyment of a soft drink. Sugar also balances flavors and acids.

Sugar-free soft drinks stemmed from a sugar scarcity during World War II. Soft drink manufacturers turned to high-intensity sweeteners, mainly saccharin, which was phased out in the 1970s when it was declared a potential carcinogen. Other sugar substitutes were introduced more successfully, notably aspartame, or Nutra-Sweet, which was widely used throughout the 1980s and 1990s for diet soft drinks. Because some high-intensity sweeteners do not provide the desired mouth-feel and aftertaste of sugar, they often are combined with sugar and other sweeteners and flavors to improve the beverage.

The overall flavor of a soft drink depends on an intricate balance of sweetness, tartness, and acidity (pH). Acids add a sharpness to the background taste and enhance the thirst-quenching experience by stimulating saliva flow. The most common acid in soft drinks is citric acid, which has a lemony flavor. Acids also reduce pH levels, mildly preserving the beverage.

Very small quantities of other additives enhance taste, mouth-feel, aroma, and appearance of the beverage. There is an endless range of flavorings; they may be natural, natural identical (chemically synthesized imitations), or artificial (chemically unrelated to natural flavors). Emulsions are added to soft drinks primarily to enhance "eye appeal" by serving as clouding agents. Emulsions are mixtures of liquids that are generally incompatible. They consist of water-based elements, such as gums, pectins, and preservatives; and oil-based liquids, such as flavors, colors, and weighing agents. Saponins enhance the foamy head of certain soft drinks, like cream soda and ginger beer.

To impede the growth of microorganisms and prevent deterioration, preservatives are added to soft drinks. Anti-oxidants, such as BHA and ascorbic acid, maintain color and flavor. Beginning in the 1980s, soft drink manufacturers opted for natural additives in response to increasing health concerns of the public.

Impurities in the water are removed through a process of coagulation, filtration, and chlorination. Coagulation involves mixing floc into the water to absorb suspended particles. The water is then poured through a sand filter to remove fine particles of Roc. To sterilize the water, small amounts of chlorine are added to the water and filtered out.

The Manufacturing Process

Most soft drinks are made at local bottling and canning companies. Brand name franchise companies grant licenses to bottlers to mix the soft drinks in strict accordance to their secret formulas and their required manufacturing procedures.

Clarifying the water

1 The quality of water is crucial to the success of a soft drink. Impurities, such as suspended particles, organic matter, and bacteria, may degrade taste and color. They are generally removed through the traditional process of a series of coagulation, filtration, and chlorination. Coagulation involves mixing a gelatinous precipitate, or floc (ferric sulphate or aluminum sulphate), into the water. The floc absorbs suspended particles, making them larger and more easily trapped by filters. During the clarification process, alkalinity must be adjusted with an addition of lime to reach the desired pH level.
Filtering, sterilizing, and dechlorinating the water

2 The clarified water is poured through a sand filter to remove fine particles of floc. The water passes through a layer of sand and courser beds of gravel to capture the particles.

3 Sterilization is necessary to destroy bacteria and organic compounds that might spoil the water's taste or color. The water is pumped into a storage tank and is dosed with a small amount of free chlorine. The chlorinated water remains in the storage tank for about two hours until the reaction is complete.

4 Next, an activated carbon filter dechlorinates the water and removes residual organic matter, much like the sand filter. A vacuum pump de-aerates the water before it passes into a dosing station.
Mixing the ingredients

5 The dissolved sugar and flavor concentrates are pumped into the dosing station in a predetermined sequence according to their compatibility. The ingredients are conveyed into batch tanks where they are carefully mixed; too much agitation can cause unwanted aeration. The syrup may be sterilized while in the tanks, using ultraviolet radiation or flash pasteurization, which involves quickly heating and cooling the mixture. Fruit based syrups generally must be pasteurized.

6 The water and syrup are carefully combined by sophisticated machines, called proportioners, which regulate the flow rates and ratios of the liquids. The vessels are pressurized with carbon dioxide to prevent aeration of the mixture.

Carbonating the beverage

7 Carbonation is generally added to the finished product, though it may be mixed into the water at an earlier stage. The temperature of the liquid must be carefully controlled since carbon dioxide solubility increases as the liquid temperature decreases. Many carbonators are equipped with their own cooling systems. The amount of carbon dioxide pressure used depends on the type of soft drink. For instance, fruit drinks require far less carbonation than mixer drinks, such as tonics, which are meant to be diluted with other liquids. The beverage is slightly over-pressured with carbon dioxide to facilitate the movement into storage tanks and ultimately to the filler machine.

Filling and packaging

8 The finished product is transferred into bottles or cans at extremely high flow rates. The containers are immediately sealed with pressure-resistant closures, either tinplate or steel crowns with corrugated edges, twist offs, or pull tabs.

9 Because soft drinks are generally cooled during the manufacturing process, they must be brought to room temperature before labeling to prevent condensation from ruining the labels. This is usually achieved by spraying the containers with warm water and drying them. Labels are then affixed to bottles to provide information about the brand, ingredients, shelf life, and safe use of the product. Most labels are made of paper though some are made of a plastic film. Cans are generally pre-printed with product information before the filling stage.

10 Finally, containers are packed into cartons or trays which are then shipped in larger pallets or crates to distributors.

Quality Control
Soft drink manufacturers adhere to strict water quality standards for allowable dissolved solids, alkalinity, chlorides, sulfates, iron, and aluminum. Not only is it in the interest of public health, but clean water also facilitates the production process and maintains consistency in flavor, color, and body. Microbiological and other testing occur regularly. The National Soft Drink Association and other agencies set standards for regulating the quality of sugar and other ingredients. If soft drinks are produced with low-quality sugar, particles in the beverage will spoil it, creating floc. To prevent such spoilage, sugar must be carefully handled in dry, sanitized environments.

It is crucial for soft drink manufacturers to inspect raw materials before they are mixed with other ingredients, because preservatives may not kill all bacteria. All tanks, pumps, and containers are thoroughly sterilized and continuously monitored. Cans, made of aluminum alloy or tin-coated low-carbon steel, are lacquered internally to seal the metal and prevent corrosion from contact with the beverage. Soft drink manufacturers also recommend specific storage conditions to retailers to insure that the beverages do not spoil. The shelf life of soft drinks is generally at least one year.

Recycling
The $27 billion dollar soft drink industry generated about 110 billion containers each year in the early 1990s. About half of soft drink containers were aluminum cans and the other half, about 35 billion, were PET plastic bottles. Nearly 60% of all soft drink containers were recycled, the highest rate for any packaging in the United States. Environmental concerns continued to lead to improvements and innovations in packaging technology, including the development of refillable and reusable containers.

The Future
In the 1990s there were more than 450 types of soft drinks on the market and new flavors and sweeteners are developed all the time to meet market demands. In the future, advanced technology will lead to greater efficiency of soft drink production at all stages. New methods of water clarification, sterilization, and pasteurization will improve production and minimize the need for preservatives in soft drinks. Concerns with consumer health, safety, and the environment will continue to have a positive impact on trends in the soft drink industry.

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Winemaking, or vinification, is the production of wine, starting with selection of the grapes or other produce and ending with bottling the finished wine. Although most wine is made from grapes, it may also be made from other fruit or non-toxic plant material. Mead is a wine that is made with honey being the primary ingredient after water.

Winemaking can be divided into two general categories: still wine production (without carbonation) and sparkling wine production (with carbonation).

PROCESS
After the harvest, the grapes are crushed and allowed to ferment. Red wine is made from the must (pulp) of red or black grapes that undergo fermentation together with the grape skins, while white wine is usually made by fermenting juice pressed from white grapes, but can also be made from must extracted from red grapes with minimal contact with the grapes' skins. Rosé wines are made from red grapes where the juice is allowed to stay in contact with the dark skins long enough to pick up a pinkish color, but little of the tannins contained in the skins.

During this primary fermentation, which often takes between one and two weeks, yeast converts most of the sugars in the grape juice into ethanol (alcohol). After the primary fermentation, the liquid is transferred to vessels for the secondary fermentation. Here, the remaining sugars are slowly converted into alcohol and the wine becomes clear. Wine is then allowed to age in oak barrels before bottling, which add extra aromas to the wine, while others are bottled directly. The time from harvest to drinking can vary from a few months for Beaujolais nouveau wines to over twenty years for top wines. However, only about 10% of all red and 5% of white wine will taste better after five years than it will after just one year.[1] Depending on the quality of grape and the target wine style, some of these steps may be combined or omitted to achieve the particular goals of the winemaker. Many wines of comparable quality are produced using similar but distinctly different approaches to their production; quality is dictated by the attributes of the starting material and not necessarily the steps taken during vinification.

Variations on the above procedure exist. With sparkling wines such as Champagne, an additional fermentation takes place inside the bottle, trapping carbon dioxide and creating the characteristic bubbles. Sweet wines are made by ensuring that some residual sugar remains after fermentation is completed. This can be done by harvesting late (late harvest wine), freezing the grapes to concentrate the sugar (ice wine), or adding a substance to kill the remaining yeast before fermentation is completed; for example, high proof brandy is added when making port wine. In other cases the winemaker may choose to hold back some of the sweet grape juice and add it to the wine after the fermentation is done, a technique known as süssreserve.

The process produces wastewater, pomace, and lees that require collection, treatment, and disposal or beneficial use.

* Harvesting and destemming
Harvest is the picking of the grapes and in many ways the first step in wine production. Grapes are either harvested mechanically or by hand. The decision to harvest grapes is typically made by the winemaker and informed by the level of sugar (called °Brix), acid (TA or Titratable Acidity as expressed by tartaric acid equivalents) and pH of the grapes. Other considerations include phenological ripeness, berry flavor, tannin development (seed colour and taste). Overall disposition of the grapevine and weather forecasts are taken into account.

* Crushing and primary fermentation
Crushing is the process of gently squeezing the berries and breaking the skins to start to liberate the contents of the berries. Desteming is the process of removing the grapes from the rachis (the stem which holds the grapes).

* Pressing
Pressing is the act of applying pressure to grapes or pomace in order to separate juice or wine from grapes and grape skins. Pressing is not always a necessary act in winemaking; if grapes are crushed there is a considerable amount of juice immediately liberated (called free-run juice) that can be used for vinification. Typically this free-run juice is of a higher quality than the press juice. However, most wineries do use presses in order to increase their production (gallons) per ton, as pressed juice can represent between 15%-30% of the total juice volume from the grape.

* Pigeage
Pigeage is a French winemaking term for the traditional stomping of grapes in open fermentation tanks.

* Cold and heat stabilization
* Secondary fermentation and bulk aging
During the secondary fermentation and aging process, which takes three(3) to six(6) months, the fermentation continues very slowly. The wine is kept under an airlock to protect the wine from oxidation.

* Malolactic fermentation
Malolactic fermentation is carried out by bacteria which metabolize malic acid and produce lactic acid and carbon dioxide. The resultant wine is softer in taste and has greater complexity. The process is used in most red wines and is discretionary for white wines.

* Laboratory tests
* Blending and fining
Different batches of wine can be mixed before bottling in order to achieve the desired taste. The winemaker can correct perceived inadequacies by mixing wines from different grapes and batches that were produced under different conditions. These adjustments can be as simple as adjusting acid or tannin levels, to as complex as blending different varieties or vintages to achieve a consistent taste.

* Preservatives
The most common preservative used in winemaking is sulfur dioxide. Another useful preservative is potassium sorbate.

* Filtration
Filtration in winemaking is used to accomplish two objectives, clarification and microbial stabilization. In clarification, large particles that affect the visual appearance of the wine are removed. In microbial stabilization, organisms that affect the stability of the wine are removed therefore reducing the likelihood of re-fermentation or spoilage.

* Bottling
A final dose of sulfite is added to help preserve the wine and prevent unwanted fermentation in the bottle. The wine bottles then are traditionally sealed with a cork, although alternative wine closures such as synthetic corks and screwcaps, which are less subject to cork taint, are becoming increasingly popular

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The brewing process is typically divided into 7 steps: mashing, lautering, boiling, fermenting, conditioning, filtering, and filling.

Today, many simplified brewing systems exist which can be used at home or in restaurants. These homebrewing systems are often employed for ease of use, although some people still prefer to do the entire brewing process themselves.

Mashing
Mashing is the process of combining a mix of milled grain, known as the grist (typically malted barley with supplementary grains as maize, sorghum, rye or wheat; in a ratio of 90-10 up to 50-50), with water, and heating this mixture up which rests at certain temperatures (notably 45°C, 62°C and 73°C [3][4]) to allow enzymes in the malt to break down the starch in the grain into sugars, typically maltose.

Wort Separation
Wort separation is the separation of the wort containing the sugar extracted during mashing from the spent grain. It can be carried out in a mash tun outfitted with a false bottom, a lauter tun, a special-purpose wide vessel with a false bottom and rotating cutters to facilitate flow, a mash filter, a plate-and-frame filter designed for this kind of separation, or in a Strainmaster. Most separation processes have two stages: first wort run-off, during which the extract is separated in an undiluted state from the spent grains, and Sparging, in which extract which remains with the grains is rinsed off with hot water.

Boiling
Boiling the malt extracts, called wort, ensures its sterility, and thus prevents a lot of infections. During the boil hops are added, which contribute bitterness, flavour, and aroma compounds to the beer, and, along with the heat of the boil, causes proteins in the wort to coagulate and the pH of the wort to fall. Finally, the vapours produced during the boil volatilise off flavours, including dimethyl sulfide precursors.

The boil must be conducted so that it is even and intense. The boil lasts between 50 and 120 minutes, depending on its intensity, the hop addition schedule, and volume of wort the brewer expects to evaporate.

Fermenting
After the wort is cooled and aerated — usually with sterile air — yeast is added to it, and it begins to ferment. It is during this stage that sugars won from the malt are metabolized into alcohol and carbon dioxide, and the product can be called beer for the first time. Fermentation happens in tanks which come in all sorts of forms, from enormous tanks which can look like storage silos, to five gallon glass carboys in a homebrewer's closet.

Most breweries today use cylindro-conical vessels, or CCVs, have a conical bottom and a cylindrical top. The cone's aperture is typically around 60°, an angle that will allow the yeast to flow towards the cones apex, but is not so steep as to take up too much vertical space. CCVs can handle both fermenting and conditioning in the same tank. At the end of fermentation, the yeast and other solids which have fallen to the cones apex can be simply flushed out a port at the apex.

Kraeusen in an English brewery's fermentation tankOpen fermentation vessels are also used, often for show in brewpubs, and in Europe in wheat beer fermentation. These vessels have no tops, which makes harvesting top fermenting yeasts very easy. The open tops of the vessels make the risk of infection greater, but with proper cleaning procedures and careful protocol about who enters fermentation chambers, the risk can be well controlled.

Fermentation tanks are typically made of stainless steel. If they are simple cylindrical tanks with beveled ends, they are arranged vertically, as opposed to conditioning tanks which are usually laid out horizontally. Only a very few breweries still use wooden vats for fermentation as wood is difficult to keep clean and infection-free and must be repitched more or less yearly.

After high kraeusen a bung device (German: Spundapparat) is often put on the tanks to allow the CO2 produced by the yeast to naturally carbonate the beer. This bung device can be set to a given pressure to match the type of beer being produced. The more pressure the bung holds back, the more carbonated the beer becomes.

Conditioning
When the sugars in the fermenting beer have been almost completely digested, the fermentation slows down and the yeast starts to settle to the bottom of the tank. At this stage, the beer is cooled to around freezing, which encourages settling of the yeast, and causes proteins to coagulate and settle out with the yeast. If a separate conditioning tank is to be used, it is at this stage that the beer will be transferred into one. Unpleasant flavors such as phenolic compounds become insoluble in the cold beer, and the beer's flavor becomes smoother. During this time pressure is maintained on the tanks to prevent the beer from going flat.

A similar technique is used in home brewing, wherein the beer is simply siphoned into another vessel (usually a carboy), leaving the now-dormant yeast and other sediment behind. The batch is then sometimes refrigerated for the aforementioned benefits.

Conditioning can take from 2 to 4 weeks, sometimes longer, depending on the type of beer. Additionally lagers, at this point, are aged at near freezing temperatures for 1-6 months depending on style. This cold aging serves to reduce sulfur compounds produced by the bottom-fermenting yeast and to produce a cleaner tasting final product with fewer esters.

If the fermentation tanks have cooling jackets on them, as opposed to the whole fermentation cellar being cooled, conditioning can take place in the same tank as fermentation. Otherwise separate tanks (in a separate cellar) must be employed. This is where aging occurs.

Filtering

Filtering the beer stabilizes the flavour, and gives beer its polished shine and brilliance. Not all beer is filtered. When tax determination is required by local laws, it is typically done at this stage in a calibrated tank.

Filters come in many types. Many use pre-made filtration media such as sheets or candles, while others use a fine powder made of, for example, diatomaceous earth, also called kieselguhr, which is introduced into the beer and recirculated past screens to form a filtration bed.

Filters range from rough filters that remove much of the yeast and any solids (e.g. hops, grain particles) left in the beer, to filters tight enough to strain color and body from the beer. Normally used filtration ratings are divided into rough, fine and sterile. Rough filtration leaves some cloudiness in the beer, but it is noticeably clearer than unfiltered beer. Fine filtration gives a glass of beer that you could read a newspaper through, with no noticeable cloudiness. Finally, as its name implies, sterile filtration is fine enough that almost all microorganisms in the beer are removed during the filtration process.

Packaging
Packaging is putting the beer into the containers in which it will leave the brewery. Typically this means in bottles, aluminium cans and kegs, but it might include bulk tanks for high-volume customers.

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Forming Oil

Oil is formed from the remains of tiny plants and animals (plankton) that died in ancient seas between 10 million and 600 million years ago. After the organisms died, they sank into the sand and mud at the bottom of the sea.

­Over the years, the organisms decayed in the sedimentary layers. In these layers, there was little or no oxygen present. So microorganisms broke the remains into carbon-rich compounds that formed organic layers. The organic material mixed with the sediments, forming fine-grained shale, or source rock. As new sedimentary layers were deposited, they exerted intense pressure and heat on the source rock. The heat and pressure distilled the organic material into crude oil and natural gas. The oil flowed from the source rock and accumulated in thicker, more porous limestone or sandstone, called reservoir rock. Movements in the Earth trapped the oil and natural gas in the reservoir rocks between layers of impermeable rock, or cap rock, such as granite or marble

Preparing to Drill

Once the site has been selected, it must be surveyed to determine its boundaries, and environmental impact studies may be done. Lease agreements, titles and right-of way accesses for the land must be obtained and evaluated legally. For off-shore sites, legal jurisdiction must be determined.

Once the legal issues have been settled, the crew goes about preparing the land:

The land is cleared and leveled, and access roads may be built.
Because water is used in drilling, there must be a source of water nearby. If there is no natural source, they drill a water well.

They dig a reserve pit, which is used to dispose of rock cuttings and drilling mud during the drilling process, and line it with plastic to protect the environment. If the site is an ecologically sensitive area, such as a marsh or wilderness, then the cuttings and mud must be disposed offsite -- trucked away instead of placed in a pit.

Once the land has been prepared, several holes must be dug to make way for the rig and the main hole. A rectangular pit, called a cellar, is dug around the location of the actual drilling hole. The cellar provides a work space around the hole, for the workers and drilling accessories. The crew then begins drilling the main hole, often with a small drill truck rather than the main rig. The first part of the hole is larger and shallower than the main portion, and is lined with a large-diameter conductor pipe. Additional holes are dug off to the side to temporarily store equipment -- when these holes are finished, the rig equipment can be brought in and set up.

Depending upon the remoteness of the drill site and its access, equipment may be transported to the site by truck, helicopter or barge. Some rigs are built on ships or barges for work on inland water where there is no foundation to support a rig (as in marshes or lakes.

Drilling

The crew sets up the rig and starts the drilling operations. First, from the starter hole, they drill a surface hole down to a pre-set depth, which is somewhere above where they think the oil trap is located. There are five basic steps to drilling the surface hole:

Place the drill bit, collar and drill pipe in the hole.
Attach the kelly and turntable and begin drilling.

As drilling progresses, circulate mud through the pipe and out of the bit to float the rock cuttings out of the hole.

Add new sections (joints) of drill pipes as the hole gets deeper.
Remove (trip out) the drill pipe, collar and bit when the pre-set depth (anywhere from a few hundred to a couple-thousand feet) is reached.

Once they reach the pre-set depth, they must run and cement the casing -- place casing-pipe sections into the hole to prevent it from collapsing in on itself. The casing pipe has spacers around the outside to keep it centered in the hole.

The casing crew puts the casing pipe in the hole. The cement crew pumps cement down the casing pipe using a bottom plug, a cement slurry, a top plug and drill mud. The pressure from the drill mud causes the cement slurry to move through the casing and fill the space between the outside of the casing and the hole. Finally, the cement is allowed to harden and then tested for such properties as hardness, alignment and a proper seal.

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The technique of glass making too is based on similar lines. People learned to make the first glass containers about two thousand years ago. Molten glass was collected on the ends of hollow iron pipes and then expanded by blowing through the pipes. Slowly, people learnt to blow molten glass into moulds. Glass bottle making machines were introduced in the thirties.

The first plastics blow molding machine was designed in the early forties; the first plastic bottles were manufactured using polythene.

In the early seventies, environmentalists began arguing on the grounds that glass and plastic bottles added to pollution. This led to the setting up of numerous recycling centers where people could return bottles for reuse in other bottles. Most of the recycled plastic is used to manufacture lower quality plastic than those used to make bottles.

There are four main ingredients used to manufacture glass:

1. Silica sand,
2. Soda ash,
3. Limestone
4. Recycled glass (cullet).

Small quantities of other materials give glass its colour.

The Process
· All the materials are first weighed then mixed, and then poured into large
furnaces. The temperature in the furnace ranges from about 1100 – 1590
degrees Celsius. This melts all the ingredients into Molten (liquid) glass.
Computers monitor the whole process.

· From the furnace, the Molten glass goes to a bottle-making machine. A
measure of molten glass (this is called a GOB) is delivered to the machine to
make a bottle or jar.

· The bottles then pass through electronic inspection machines, which
automatically detect faults Rejected damaged bottles, are returned to the raw
materials area and recycled for making new glass.

· The bottles are then packed onto pallets. Each pallet can contain as many as
5000 bottles. The pallet is then covered in a large plastic envelope that has
been shrunk until tight. This makes sure the pallet is stable, ready for
transportation to the manufactures for filling.

Bottle Making (Molding Process)

Annealing is done by reheating the glass and gradually cooling it. Such a process removes the stresses and strains in the glass after shaping. This is an important step and if not done may cause the glass to shatter as a result of the build up of tension caused by uneven cooling. After the bottles have cooled to room temperature, they are inspected and finally packaged.

Plastic bottles may be made from polyethylene, polypropylene or polyvinyl chloride. Large cold drink bottles are made of polyethylene terephalate (PET). These bottles are designed in such a way that the gases used to carbonate the soft drinks are unable to escape.

There are three different methods used for processing plastic bottles – extrusion blow molding (in which the parison is tube shaped), injection blow molding (in which the parison is prepared by injecting molten plastic through a small hole) and injection stretch blow molding (in which the plastic is blown into the mould while it is simultaneously being stretched by a metal rod).

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MINING DIAMONDS
Of all the diamonds mined in the world each year, less than half are gem quality; the rest fall into two other main categories known as near-gem quality and industrial quality diamonds. Gem quality diamonds display a high standard of excellence in quality and are used in jewellery. The clarity of these diamonds ranges from flawless through to visible inclusions. Near-gem quality diamonds represent those stones of a quality between gem and industrial, that in fact can be used as either depending on the individual stone. These stones have clarity grades ranging from visible inclusions through to industrial. Industrial quality diamonds are low quality or badly included stones and are suitable only for industrial use; for example, they are used in dentist's drills and earthmoving equipment.

Diamonds are recovered by way of pipe or alluvial mining.

Pipe Mining:
Pipe mining refers to the extraction of diamonds from volcanic pipes. Typically, a very large area has to be covered. An average of 250 tons of ore must be mined in order to produce a one-carat gem uality polished diamond. In most countries, a diamond pipe mine is composed of kimberlite, or blue ground. Initially kimberlite is dug from the surface of the pipes in rough opencast mining. Once the surface deposits have been exhausted, shafts are sunk into the ground at the edge of the pipes, and tunnels are driven into the eeper parts of the pipes.

In open cut mining, the ore is dislodged by blasting and then loaded by excavators into 120-ton dump trucks. The ore is then transported to the processing plant where the diamonds are extracted. The processing techniques are purely physical and involve crushing, scrubbing, screening and gravity separation of the diamond-bearing ore. Final diamond recovery is achieved by the use of x-ray sorting machines. The machines can detect and remove diamond material because the diamonds fluoresce under x-ray.

Alluvial Mining:
This process involves the extraction of diamonds from riverbeds or ocean beaches. Millions of years ago, at the time the diamond pipes were formed, some diamonds were weathered out of the pipes and carried great distances long rivers and even into oceans. In order to extract these diamonds from beaches, a wall is built to hold back the surf. Up to 25 meters of sand is bulldozed aside to reach the diamond-bearing level. Once reached, the diamond-bearing earth is removed and transported to screening plants.

Screening Process:
Once a mining operation yields ore, the diamonds must be sorted from the other materials. This process relies primarily on diamond's high density. An old but effective method is to use a washing pan, which forces heavy minerals like diamond to the bottom and waste to the top. Cones and cyclones use swirling heavy fluids mixed with crushed ore to achieve density separations. With 99 percent of the waste in the ore removed, further separations may use either a grease table or an x-ray separator. Final separation and sorting is done by eye.
Crushed ore is mixed with a muddy water suspension, called puddle, and all is stirred by angled rotating blades in the circular washing pan. Heavier minerals settle to the bottom and are pushed toward an exit point, while lighter waste rises to the top and overflows as a separate stream of material. The surface of diamond is highly unusual in that it resists being wetted by water but sticks readily to grease. Here, wet gravel washes across 3 inclined surfaces covered with beeswax and paraffin. Diamonds stick to the grease while wetted waste minerals flow past. The operator routinely scrapes the material that adheres to the table into a grease pot, using a trowel. The grease in the pot is melted and the diamonds are removed in a strainer. More automated systems use a rotating grease belt and craper.

Cones (left) and cyclones (right) use heavy-media separation. Diamond-bearing concentrate is mixed with a fluid near the density of diamond. Separation occurs in cones and cyclones by swirling the mixture at low and high velocities respectively. In the cone, rotational mixing permits lighter minerals to float to the top and run out as overflow, while diamonds and dense minerals sink to the bottom and are sucked out ith a compressed air siphon.

In the cyclone, fast rotation of the suspension drives heavy minerals to the conical wall, where they sink to the bottom and are extracted, while float waste minerals are sucked from the center of the vortex. Cyclones are about 99.999% efficient at concentrating diamonds and similarly dense inerals from the original ore. The x-ray separator system acts on a thin stream of particles from the concentrate accelerated off a moving belt into the air, where they encounter an intense beam of x-rays. Any diamond fluoresces in the x-rays, activating a photomultiplier that triggers a jet of air, deflecting the diamonds (blue) into a collector bin.

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Depending on the depth of the coal layers (seams), extraction is achieved by means of open-cast (down to a depth 500m) or underground mines.

An opencast operation has the appearance of an enormous hole, organised a bit like a stadium with terraces, along which machines dig into the seams. But what a stadium! The biggest opencast mines are several kilometres in length and hundreds of meters in depth. In underground mines, the coal is extracted by means of vertical or inclined shafts. At each level where coal is present, these shafts are linked together by a vast network of galleries (10 to 20 m² in cross-section). These networks can be made up of several dozens of kilometres of galleries. The coal is extracted by enormous machines (the coalcutters). It is transported to the surface where it is separated from the sands and clays by flotation (the coal floats and the other mineral materials, known as “steriles”, sink to the bottom). Extraction by opencast mining is more productive and less expensive than underground mining. As a result it is more profitable. Working conditions are also a significantly less dangerous. Unfortunately, opencast mining is less environmentally friendly; the countryside is disfigured and the surface activity tends to pollute the atmosphere within the locality.

The majority of coalmines in the world are underground.

Methods of extraction of coal:

- Opencast mining: the soil layers located above the first coal layer (the overburden) are removed. Then extraction can begin. When the hole is sufficiently large, digging continues as far as the subsequent coal layer, where the coal is extracted in the same way, simultaneously with continued extraction of the first layer, and so on. Each of the coal layers is called a “discovery”. The mine gradually becomes a giant amphitheatre, the terraces of which are made up of the layers of coal being extracted. It is more a terracing activity than mining. Giant excavators dig out the coal. Their buckets can contain up to 300 tons of rock. The production from an opencast or strip mine starts 2 to 5 years after the initial work. The technique is less expensive, more profitable and less dangerous than extraction by underground mining. Nevertheless it is little used in Europe, where the coal is generally too deeply buried.

- Underground mines: to reach the coal-bearing rocks, vertical shafts are dug, into which lifts and other systems for links with the surface are installed. At the levels of the coal-bearing seams (layers), digging takes place horizontally, following each seam for as long as possible. Several techniques are used:
In each seam exploited, regularly spaced large pillars of coal are left in place to support the roof: this is called the “room and pillar method”;
Or two parallel tunnels are dug and a machine (a giant rasp or undercutter) goes backwards and forwards between these tunnels, extracting coal at each step: it is the “long coal face” or “long wall” method, which allows recovery of a little more coal than the preceding method. As the coalface moves forward, the roof is allowed to collapse behind (miners talk about “thundering”). The main disadvantage is that the effects of these roof collapses are sometimes felt on the surface, and the buildings and roadways located above the mine suffer the consequences of subsidence: they crack and sometimes even disappear into a hole! To solve this problem, the deliberate collapsing of the roof can be replaced by a filling procedure: the «sterile» rocks replace the extracted coal. But that is more expensive;
In mountainous regions, the galleries can be dug horizontally, directly into the side of the hill, whereas, on the plains, infrastructures are necessary to bring the coal-bearing rocks to the surface. Pumping and drainage equipment is essential although if the mines are in the mountains the evacuation of water usually happens naturally. Conveyors or trains of large wagons transport the extracted coal to the vertical shafts. Finally the coal is taken up to the surface by means of a bucket conveyor driven by very powerful electric motors.

MACHINERIES USED:

Machines make mining easier, quicker, and sometimes safer. Here are some of the machines used in mining:

* Surface Mining:

- Wheel loaders: These are used when a lot of mining materials need to be moved at one time.

- Excavator: Most surface mines have one of these. This machine is used to do the digging. Usually this machine dumps the materials that it dug up into a dump truck.

- Dump Trucks: These are used to take away or move materials. You can see how big it is compared to the driver. Sometimes these are called monster trucks because they are so big.

- Crawler-tractor [bull dozer]: Sometimes these are called dozers. Instead of rubber tires, these have chains. Chain tractors are used on land where rubber tires won't work too well--like in mud or on mountain slopes. Dozers push dirt from one place to another. When mines close and they begin to fix the land that has been changed, dozers push dirt and materials where they need to go.

- Motor grader: These are used to make the ground level when they are clearing off the land for mining or fixing it when they are done.

* Underground mining:

- Articulated Dump Trucks: These are used to move large amounts of material in the mine. They can turn easier inside mines than most trucks can.

- Continuous miner: This machine is used to cut out long sections of the inside walls of the mine. They use this machine instead of blasting and drilling. Click here for pictures.

- Longwall mining equipment: This is used to cut out the coal in layers. Part of the machinery will hold up the roof, too. Click here for a picture.

- Shuttle car: These were used to take out the coal or minerals from the mine. They look a little like our buttons on the left, but not colorful. The ore or coal was loaded into these to be taken out of the mine. Trucks are used for this in up-to-date mines.

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Process Description
Figure 9.7-1 is a flow diagram of a typical cotton-ginning process. Each of the five ginning steps and associated equipment is described below.

Unloading System -
Module trucks and trailers transport cotton from the field to the gin. A pneumatic system removes the cotton from the trailers, and either a pneumatic system or a module feeder removes the cotton from modules. A combination conveyer and pneumatic system conveys the cotton to a separator and feed control unit. Prior to this first separator point, some gins use a stone and green boll trap for preliminary trash removal. The screen assembly in the separator allows air to escape but collects the cotton and allows it to fall into the feed control unit. The conveying air flows from the separator to a cyclone system, where it is cleaned and discharged to the atmosphere.

Seed Cotton Cleaning System -
Cotton is subjected to three basic conditioning processes--drying, cleaning, and
extracting- before it is processed for separation of lint and seed. To ensure adequate conditioning, cotton gins typically use two conditioning systems (drying, cleaning, and extracting) in series.

Seed cotton dryers are designed to reduce lint cotton moisture content to 5 to 8 percent to facilitate cleaning and fiber/seed separation. A high-pressure fan conveys seed cotton through the drying system to the first seed cotton cleaner, which loosens the cotton and removes fine particles of foreign matter (e. g., leaf trash, sand, and dirt). In the second cleaner, large pieces (e. g., sticks, stems, and burs) are removed from the cotton by a different process, referred to as "extracting". Different types of extractors may be used, including bur machines, stick machines, stick and bur machines, stick and green leaf extractors, and extractor/feeders. These machines remove burs, sticks, stems, and large leaves, pneumatically conveying them to the trash storage area. The cotton is pneumatically conveyed to the next processing step. Typically, all conveying air is cleaned by a cyclone before being released to the atmosphere.

Overflow System -
After cleaning, the cotton enters a screw conveyor distributor, which apportions the cotton to the extractor/feeders at a controlled rate. The extractor/feeders drop the cotton into the gin stands at the recommended processing rates. If the flow of cotton exceeds the limit of the extractor/feeder systems, the excess cotton flows into the overflow hopper. A pneumatic system (overflow separator) then returns this cotton back to the screw conveyor distributor, as required. Typically, the air from this system is routed through a cyclone and cleaned before being exhausted to the atmosphere.

Ginning and Lint Handling System -
Cotton enters the gin stand through a "huller front", which performs some cleaning. Saws grasp the locks of cotton and draw them through a widely spaced set of "huller ribs" that strip off hulls and sticks. (New gin stands do not have huller ribs.) The cotton locks are then drawn into the roll box, where fibers are separated from the seeds. After all the fibers are removed, the seeds slide down the face of the ginning ribs and fall to the bottom of the gin stand for subsequent removal to storage. Cotton lint is removed from the saws by a rotating brush, or a blast of air, and is conveyed pneumatically to the lint cleaning system for final cleaning and combing. The lint cotton is removed from the conveying airstream by a condenser that forms the lint into a batt. The lint batt is fed into the first lint cleaner, where saws comb the lint cotton again and remove part of the remaining leaf particles, grass, and motes. Most condensers are covered with fine mesh wire or fine perforated metal, which acts to filter short lint fibers and some dust from the conveying air.

Battery Condenser And Baling System -
Lint cotton is pneumatically transported from the lint cleaning system to a battery condenser, which is a drum covered with fine mesh screen or fine perforated metal that separates the lint cotton from the conveying air. The lint cotton is formed into batts and fed into a baling press, which compresses the cotton into uniform bales.

Most gins use a double-press box for packaging the cotton into bales. The lint drops into one press box and fills it while a bale is being pressed and strapped in the other box. Approximately 480 lb (217 kilograms [kg]) of cotton is pressed into a bale before it is wrapped with a cover and strapped. Modern gins are presently equipped with higher-tonnage bale presses that produce the more compact universal density cotton bales. In 1995, 96 percent of the U.S. crop was pressed into universal density bales at the gins. The finished cotton bale is transported to the textile mill for processing into yarn. Motes are sometimes cleaned and baled also.

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Manufacture Process

The principal raw materials for fertilizer production are air (to provide nitrogen), natural gas (to provide hydrogen for ammonia synthesis) phosphate rock, potash and sulfur (for suifuric acid production and subsequent use in phosphate fertilizer production). Fossil fuels are also used for power generation in the mining and processing of raw materials. As with other industries, mining and treatment of each raw material may raise environmental problems.

Use of natural gas for fertilizer production contributes around 2 per cent of global carbon dioxide emissions. The increased availability of nitrogen from fertilizers, manures and leguminous crops further adds to greenhouse emissions by the formation of increased amounts of nitrous oxide. These sources together may contribute as much as 3 to 5 per cent of the long term greenhouse effect. However, use of fertilizers stimulates plant growth and photosynthesis, removing carbon dioxide from the air. The overall effect of fertilizers on greenhouse gas emissions is therefore likely to be a positive one. Further, should soil organic matter concentrations increase due to fertilizer use, more carbon becomes 'locked away' in the soil.

Mining of phosphates and potash may damage the landscape. Phosphate rock is usually open-mined, generating large amounts of waste overburden. large scale restoration of the landscape is required. Some phosphate rock contains minor amounts of radioactive elements (e.g. uranium) necessitating special storage for mining waste. Leaching of waste may cause water pollution. Potassium extraction may also lead to water pollution when brines are produced as a by-product. Large stockpiles of common salt (sodium chloride) are often generated during the processing of potash ores.

Extraction of sulfur from industrial smoke stack gases, e.g. metal processing plants and fossil fuel power stations, may in fact minimise environmental impact by utilising sulfur dioxide, which may otherwise be emitted to the atmosphere, possibly contributing to acid rain.

Some emissions may occur during the manufacturing processes. Nitrogen oxides, ammonia, fluorides and sulfur dioxide, along with fertilizer dust, may be emitted. Losses however are small, less than 1 per cent of the nutrients handled.

Type of Fertilizers

The nutrients of most concern are nitrogen and phosphorus given their widespread use.

Nitrogen Fertilizers:

Excessive or inappropriately applied nitrogen fertilizers can lead to emissions of ammonia (by volatilisation) and nitrous oxides (by denitrification). The latter may contribute to greenhouse effects. The dominant source of atmospheric ammonia is from farm animals and manures, with fertilizer use contributing only an estimated 10 per cent of atmospheric ammonia in Western Europe. While ammonia concentrations in the air are too low (of the order of micrograms per cubic metre) to affect air quality, they may contribute to acid rain and soil acidification in these densely settled and intensely cropped regions.

Nitrogen fertilizers readily convert to nitrate in the soil. The nitrogen in soil organic matter and organic fertilizers becomes available more slowly. Nitrate from all sources may be readily leached if not used by crops or pasture. Leaching is particularly likely in sandy soils following heavy rainfall. Leached nitrate may contaminate underground water. This is of concern if the water is to be used for human or livestock consumption, as high concentrations of nitrate may affect health. Nitrate combines with haemoglobin, interfering with oxygen transport in the blood, particularly in young children. World standards are set for nitrate levels in drinking water (10 mg/L NO3- N or 45mg/L N03-). Nitrate contamination of groundwater is not of concern in most parts of Australia as little use is made of shallow underground water for drinking, and Australia's agriculture is far less intensive than in Europe and North America. Leaching of nitrate can be minimised by good fertilizer management (recommended rates, soil and plant tissue analysis, application when maximum uptake occurs, split-application etc.).

The use of fertilizers, particularly nitrogen fertilizers can accelerate the natural process of soil acidification. The initial effect fertilizers have on soil pH in the immediate vicinity of the granules is usually of little consequence. While some fertilizers are acidic e.g. MAP and others basic e.g. DAP, their effects are confined to the point of application. Due to the relatively small volume of soil affected compared to total soil volume, there is little effect on sail pH. Some fertilizers e.g. anhydrous ammonia and urea may initially raise the soil pH at the site of application but in the long term acidify the soils. This occurs when ammonium is converted to nitrate.

Superphosphate is popularly held to be responsible for soil acidification. It does not directly cause soil pH to fall, but since it does promote legume growth and nitrogen fixation it will, like most nitrogen fertilizers, have an indirect effect on soil pH. Any practice which increases plant growth such as proper fertilization will lead to the gradual acidification of the soil by two main processes. They are the formation and loss of nitrate through the soil, and removal of nutrients in the form of farm produce.

Removal of plant and animal produce removes alkaline cations such as calcium and magnesium, along with some acidic elements. There is an overall acidifying effect on the soil. Any accumulation of organic matter in the soil increases the amount of nitrogen stored in the soil. Organic nitrogen is then converted to ammonium and subsequently to nitrate by nitrification. In the process, hydrogen ions are formed i.e. acid is produced. Much of this increased nitrogen comes from fixation by legumes, and from fertilizer application. Acid produced in the nitrification process can be used if the nitrate is taken up by plants or soil organisms, but if the nitrate is leached beyond the root zone, acidification occurs. The effect then of intensive agricultural systems is one of soil acidification.

The effects of soil acidification include reduced availability of the trace element molybdenum, development of aluminium and manganese toxicity and modulation failure in legumes. Soil analysis is used in diagnosing soil acidity problems. Lime may be required where acidity is a problem. Lime (obtained from naturally occurring calcium carbonate) neutralises soil acidity and acts as a soil conditioner. Application rates depend upon the soil type, degree of acidity and crop being grown and may vary from 1-10 tonnes per hectare. The use of acid tolerant plant species is another management strategy.

Phosphorus fertilizers:

Excess amounts of phosphorus have been associated with the eutrophication of lakes and waterways, and with algal blooms. Nitrogen may also contribute; the level of nitrogen influencing the algal type. When nitrogen levels are low, blue-green algae which fix their own nitrogen are favoured.

Blue-green algae (more correctly named Cyanobacteria) are naturally present in small numbers in healthy waterways. During periods of prolonged dry weather, water stagnates, evaporation is high and nutrient levels become concentrated. These conditions of still waters, strong sunlight and high nutrient levels (particularly phosphorus) lead to rapid multiplication of the algae, and consequent algal blooms. The blue-green algae release toxins which cause sickness in humans and livestock. The bloom is fed by phosphorus in a mixture of soil run-off, sewage, manure from farm animals and wildlife and decaying material which enters the waterways, plus recycling of nutrients from within the waterway.

Given that phosphorus is relatively immobile in soils, leaching of fertilizer phosphorus is unlikely to cause build-up in waterways. This has happened, however, on deep sands in the south-west of Western Australia. Phosphorus present in surface water run-off may originate from soil erosion or freshly top-dressed fertilizer. Erosion of fertile top-soil, where fertilizer nutrients accumulate is another source of nutrient input to waterways. Soil conservation and cultural practices which reduce soil erosion can significantly reduce phosphorus inputs into waterways.

While the use of fertilizers can contribute to nutrient overload and consequent algal blooms, the extent of the contribution has not been measured and defined. It is one of many sources, and possibly a minor one. Minimising potential impact of fertilizers involves good fertilizer practices (appropriate application rates, timing and application techniques) to minimise potential losses. Management practices (improved erosion and run-off control and buffer vegetation around waterways) also contribute to minimising environmental effects.

Phosphorus fertilizers contain various impurities from the phosphate rock and acid used in manufacture. Cadmium (Cd) is of most concern. levels of cadmium in fertilizer will vary with the phosphate rock source. As there is currently no commercial means of removing cadmium during fertilizer manufacture, the only control is to use fertilizer made from low cadmium phosphate rock, especially in areas of intensive use, e.g. vegetables.

Use of phosphorus fertilizers may lead to a build-up of the heavy metal cadmium in soils. Cadmium is normally present in soils at levels of 0.1-1.0 mg/kg soil. Phosphorus fertilizers contain higher levels of cadmium as an impurity, so prolonged use over time increases soil cadmium levels. Cadmium input to soils also occurs from the atmosphere e.g. near industrial centres, and in sewage sludge.

The use of phosphorus fertilizers may increase cadmium concentrations in farm produce, which in some situations may exceed maximum permissible levels. This is most noticeable with certain crops e.g. potatoes and leafy vegetables (lettuce and spinach) and in the offal (kidneys and liver) of animals. Use of fertilizers with a low cadmium content i.e. less than 100 mg of cadmium per kg of phosphorus (P) and preferably less than 50 mg of cadmium per kg P is recommended, especially in vegetable production.

Reference:
http://www.incitecfertilizers.com.au/environmental_facts.cfm

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Cement Process

- QUARY
Basic Elements

For its raw materials, cement uses minerals containing the four essential elements for its creation: calcium, silicon, aluminum and iron.

Raw Materials

Most plants rely on a nearby quarry for limestone. The most common combination of ingredients is limestone (for calcium) coupled with much smaller quantities of clay and sand (as sources of silica, aluminum and iron). Other raw materials, such as mill scale, shale, bauxite and fly ash are brought in from outside source when necessary.

Crusher

Rock blasted from the quarry face is transported to the primary crusher, where chair sized rocks are broken into pieces the size of baseballs. A secondary crusher reduces them to the size of gravel. Some plants now crush materials in a single stage

- PROPORTIONING, BLENDING & GRINDING

The raw materials are now analyzed in the plant laboratory, blended in the proper proportion, and then ground even finer. Plant grind the raw materials into powder against a rotating table. After grinding, the material is now ready for the kiln or preheater, depending on plant type.

- PREHEATER TOWER

The preheater tower supports a series of vertical cyclone chambers through which the raw materials pass on their way to the kiln. To save energy, modern cement plants preheat the materials before they enter the kiln. Rising more than 200 feet, hot exit gases from the kiln heat the raw materials as they swirl throught the cyclones

- KILN

Raw materials now enter the huge rotatign furnae called kiln. It's the heart of the cement making process - a horizontally sloped steel cylinder, lined with firebrick, turning from about one to three revolutions per minute. The kiln is the world's largest piece of moving industrial equipment.

From the preheater, the raw material enters the kiln at the upper end. It slides and tumbles down the kiln through progressively hotter zones toward the flame. At the lower end of the kiln, fuels such as powdered coal and natural gas feed a flame that reaches 3400'F (1870 'C) - one-third of the temperature of the sun's surface. Here in the hottest part of the kiln, the raw materials reach about 2700 F (1480C) and become partially molten.

This intense heat triggers chemical and physical changes. Expressed at its simplest, the series of chemical reactions converts the calcium and silicon oxides into calcium silicates, cement's primary constituent. At the lower end of the kiln, the raw materials emerge as a new substance; red hot particles called clinker.

- CLINKER COOLER & FINISH GRINDING

The clinker tumbles onto a grate cooled by forced air. Once cooled the clinker is ready to be ground into the gray powder known as portland cement.

To save energy, heat recovered from this cooling process is recirculated back to the kiln and preheater tower.

The clinker is ground in a ball mill - a horizontal steel tube filled with steel balls. As the tube rotates, the steel balls tumble and crush the clinker into a super-fine powder. It can now be considered portland cement. The cement is so fine it will easily pass through a sieve that is fine enough to hold water. A small amount of gypsum is added during final grinding to control the set.

- BAGGING & SHIPPING

From the grinding mills, the cement is conveyed to silos where it awaits shipment. Most cement is shipped in bulk by trucks, rail or barge. A small percentage of the cement is bagged for customes who need only small amounts or for special uses such as mortar. Most cement is shipped to ready-mixed concrete producers. There, it's combined with water, sand and gravel to make concrete delivered in the familiar truks with revolving drums. Cement is also used for a wide array of precast concrete products.



Raw Materials

The main raw materials used in the cement manufacturing process are limestone, sand, shale, clay, and iron ore. The main material, limestone, is usually mined on site while the other minor materials may be mined either on site or in nearby quarries. Another source of raw materials is industrial by-products. The use of by-product materials to replace natural raw materials is a key element in achieving sustainable development.


Raw Material Preparation


Mining of limestone requires the use of drilling and blasting techniques. The blasting techniques use the latest technology to insure vibration, dust, and noise emissions are kept at a minimum. Blasting produces materials in a wide range of sizes from approximately 1.5 meters in diameter to small particles less than a few millimeters in diameter.


Material is loaded at the blasting face into trucks for transportation to the crushing plant. Through a series of crushers and screens, the limestone is reduced to a size less than 100 mm and stored until required.


Depending on size, the minor materials (sand, shale, clay, and iron ore) may or may not be crushed before being stored in separate areas until required.


Raw Grinding

In the wet process, each raw material is proportioned to meet a desired chemical composition and fed to a rotating ball mill with water. The raw materials are ground to a size where the majority of the materials are less than 75 microns. Materials exiting the mill are called "slurry" and have flowability characteristics. This slurry is pumped to blending tanks and homogenized to insure the chemical composition of the slurry is correct. Following the homogenization process, the slurry is stored in tanks until required.


In the dry process, each raw material is proportioned to meet a desired chemical composition and fed to either a rotating ball mill or vertical roller mill. The raw materials are dried with waste process gases and ground to a size where the majority of the materials are less than 75 microns. The dry materials exiting either type of mill are called "kiln feed". The kiln feed is pneumatically blended to insure the chemical composition of the kiln feed is well homogenized and then stored in silos until required.


Pyroprocessing

Whether the process is wet or dry, the same chemical reactions take place. Basic chemical reactions are: evaporating all moisture, calcining the limestone to produce free calcium oxide, and reacting the calcium oxide with the minor materials (sand, shale, clay, and iron). This results in a final black, nodular product known as "clinker" which has the desired hydraulic properties.


In the wet process, the slurry is fed to a rotary kiln, which can be from 3.0 m to 5.0 m in diameter and from 120.0 m to 165.0 m in length. The rotary kiln is made of steel and lined with special refractory materials to protect it from the high process temperatures. Process temperatures can reach as high as 1450oC during the clinker making process.


In the dry process, kiln feed is fed to a preheater tower, which can be as high as 150.0 meters. Material from the preheater tower is discharged to a rotary kiln with can have the same diameter as a wet process kiln but the length is much shorter at approximately 45.0 m. The preheater tower and rotary kiln are made of steel and lined with special refractory materials to protect it from the high process temperatures.


Regardless of the process, the rotary kiln is fired with an intense flame, produced by burning coal, coke, oil, gas or waste fuels. Preheater towers can be equipped with firing as well.


The rotary kiln discharges the red-hot clinker under the intense flame into a clinker cooler. The clinker cooler recovers heat from the clinker and returns the heat to the pyroprocessing system thus reducing fuel consumption and improving energy efficiency. Clinker leaving the clinker cooler is at a temperature conducive to being handled on standard conveying equipment.


Finish Grinding and Distribution

The black, nodular clinker is stored on site in silos or clinker domes until needed for cement production. Clinker, gypsum, and other process additions are ground together in ball mills to form the final cement products. Fineness of the final products, amount of gypsum added, and the amount of process additions added are all varied to develop a desired performance in each of the final cement products.


Each cement product is stored in an individual bulk silo until needed by the customer. Bulk cement can be distributed in bulk by truck, rail, or water depending on the customer's needs. Cement can also be packaged with or without color addition and distributed by truck or rail.

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The first completely automated loom was made by Jacques Vaucanson in 1745. It was used for silk but didn't develop further. Edmund Cartwright built and patented a power loom in 1785, and it was this that was adopted by the nascent cotton indudstry. Powered looms were shuttle-operated for two hundred years. In the early part of the 20th century the faster and more efficient shuttleless rapier looms and air looms came into use. Modern industrial looms can weave at speeds 2000 Weft insertions per minute. Today, advances in technology have produced a variety of looms designed to maximize production for specific types of material. The most common of these are air-jet looms and water-jet looms. Computer-driven looms are now also available to individual (non-industrial) weavers.

Knitting looms
Knitting looms (also known as Amish looms or knitting boards) were recently popularized in crafting circles by the Knifty Knitter system. Knitting looms are a descendant of the frame loom. Grooved pegs are spaced along a central frame. These pegs are wrapped with yarn in various ways, then the knitter uses an angled hook to pull the wrapped yarn over the top of the peg, resulting in a fabric with stitches similar to a needle knitted item.


Bow Looms
A type of loom used for thin strips of beading. A bow loom consists of a bendable branch of cedar, willow or other easily bendable types of wood. 10-11 holes are then made along the length of two smaller pieces of wood. Thread is looped through the holes and attached to the long bendable piece. Once the bow is threaded, the thread is then used for beading. This method was traditionally used by the Native Americans.


Shuttle looms
The major components of the loom are the warp beam, heddles, harnesses, shuttle, reed and takeup roll. In the loom, yarn processing includes shedding, picking, battening and taking-up operations.

Shedding. Shedding is the raising of the warp yarns to form a shed through which the filling yarn, carried by the shuttle, can be inserted. The shed is the vertical space between the raised and unraised warp yarns. On the modern loom, simple and intricate shedding operations are performed automatically by the heddle frame, also known as a harness. This is a rectangular frame to which a series of wires, called heddles, are attached. The yarns are passed through the eye holes of the heddles, which hang vertically from the harnesses. The weave pattern determines which harness controls which warp yarns, and the number of harnesses used depends on the complexity of the weave.

Picking. As the harnesses raise the heddles, which raise the warp yarns, the shed is created. The filling yarn in inserted through the shed by a small carrier device called a shuttle. The shuttle is normally pointed at each end to allow passage through the shed. In a traditional shuttle loom, the filling yarn is wound onto a quill, which in turn is mounted in the shuttle. The filling yarn emerges through a hole in the shuttle as it moves across the loom. A single crossing of the shuttle from one side of the loom to the other is known as a pick. As the shuttle moves back and forth across the shed, it weaves an edge, or selvage, on each side of the fabric to prevent the fabric from raveling.

Battening. As the shuttle moves across the loom laying down the fill yarn, it also passes through openings in another frame called a reed (which resembles a comb). With each picking operation, the reed presses or battens each filling yarn against the portion of the fabric that has already been formed. Conventional shuttle looms can operate at speeds of about 150 to 160 picks per minute.

With each weaving operation, the newly constructed fabric must be wound on a cloth beam. This process is called taking up. At the same time, the warp yarns must be let off or released from the warp beams.

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Sugarcane is a perennial herb belonging to the grass family. Native to tropical and subtropical regions of the world, this tropical grass is 10-24-feet tall. bears long, pointed leaves, and has several stalks. The segmented stalks have a bud at each joint and as the plant matures, small flowers appear.

PLANTING

Sugarcane cuttings are planted in fields by workers or mechanical planters. In order for the cane to grow, the seeds must be planted in well-drained soil. Typical cane soil is made of a mixture of silt, sand, clay particles and organic matter. Canes are spaced at least 4-feet apart and lined in rows and covered with soil. Fertilizers are applied from the time of planting up until the beginning of the ripening period. Cane fields are also routinely weeded to provide for optimum growth of the cane. Depending on the region where the crop is planted, cane seasons last from 8-22 months. In the United States, sugarcane is grown in Florida, Hawaii, Louisiana and Texas.


COLLECTING THE HARVEST

Mature canes are gathered by a combination of manual and mechanical methods. Canes are cut at ground level, its leaves are removed and the top is trimmed off by cutting off the last mature joint. Cane is then placed into large piles and picked up, tied, and transported to a sugar factory.


CLEANSING AND GRINDING

Stalks are thoroughly washed and cut when reaching the sugar mill. After the cleaning process, a machine led by a series of rotating knives, shreds the cane into pieces. This is known as "grinding." During grinding, hot water is sprayed on to the sugarcane to dissolve any remaining hard sugar. The smaller pieces of cane are then spread out on a conveyer belt.

JUICING

The shredded pieces of sugarcane travel on the conveyer belt through a series of heavy-duty rollers, which extract juice from the pulp. The pulp that remains or "bagasse" is dried and used as fuel. The raw juice moves on through the mill to be clarified.


CLARIFYING

Carbon dioxide and the milk of a lime are added to the liquid sugar mixture and it is heated to the boiling point, as the process of clarifying begins. As the carbon dioxide travels through the liquid it forms calcium carbonate, which attracts non-sugar debris (fats, gums, and wax) from the juice, and pulls them away from the sugar juice. The juice is then pushed through a series of filters to remove any remaining impurities.


EVAPORATION

The clear juice which results from the clarifying process is put under a vacuum, where the juice boils at a low temperature and begins to evaporate. It is heated until it forms into a thick, brown syrup.


CRYSTALLIZATION

By evaporating what little water is left in the sugar syrup, crystallization takes place. Inside a sterilized vacuum pan, pulverized sugar is fed into the pan as the liquid evaporates, causing the formation of crystals. The remaining mixture is a thick mass of large crystals, which is sent to a centrifuge to spin and dry the crystals. The dried product is raw sugar, still inedible.


REFINERY

Raw sugar is transported to a Cane Sugar Refinery for the removal molasses, minerals and other non-sugars, which still contaminate the sugar. This is known as the purification process. Raw sugar is mixed with a solution of sugar and water to loosen the molasses from the outside of the raw sugar crystals, producing a thick matter known as "magma." Large machines then spin the magma, which separate the molasses from the crystals. Crystals are promptly washed, dissolved and filtered to remove impurities. The golden syrup which is produced is then sent through filters to remove the color and water. What's left is a concentrated, clear syrup, which is again fed into a vacuum pan.


SEPARATION AND PACKAGING

Once the final evaporation and drying process is done, screens separate the different sized sugar crystals. Large and small crystals are packaged and shipped, labeled as white, refined, sugar.


SUGAR FACTS

REFINED white sugar is 99.9-percent sucrose.


WHITE sugar is pure sucrose, containing no preservatives or additives.

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INTRODUCTION:
As Carding machine design improved in 1950's and 60's, it became apparent that card clothing was a limiting factor
Much time and effort was spent in the development of metallic card clothing.
• There are two rules of carding

1. The fibre must enter the carding machine, be efficiently carded and taken from it in as little time as possible
2. The fibre must be under control from entry to exit

• Control of fibres in a carding machine is the responsibility of the card clothing
• Following are the five types of clothings used in a Carding machine

1. Cylinder wire
2. Doffer wire
3. Flat tops
4. Licker-in wire
5. Stationary flats

CYLINDER WIRE:
The main parameters of CYLINDER Card clothing
1. Tooth depth
2. Carding angle
3. Rib width
4. Wire height
5. Tooth pitch
6. Tooth point dimensions

• TOOTH DEPTH:
1. Shallowness of tooth depth reduces fibre loading and holds the fibre on the cylinder in the ideal position under the carding action of the tops. The space a fibre needs within the cylinder wire depends upon its Micronaire/denier value and staple length could have to be reduced.
2. The recent cylinder wires have a profile called "NO SPACE FOR LOADING PROFILE"(NSL). With this new profile, the tooth depth is shallower than the standard one and the overall wire height is reduced to 2mm , which eliminates the free blade in the wire. This free blade is responsible for fibre loading. Once the fibre lodges between the free blade of two adjacent teeth it is difficult to remove it. In order to eliminate the free blade, the wire is made with a larger rib width
• FRONT ANGLE:
1. Front angle not only affects the carding action but controls the lift of the fibre under the action of centrifugal force. The higher the cylinder speed , the lower the angle for a given fibre. Different fibres M have different co-efficients of friction values which also determine the front angle of the wire.
2. If the front angle is more, then it is insufficient to overcome the centrifugal lift of the fibre created by cylinder speed. Therefore the fibre control is lost, this will result in increasing flat waste and more neps in the sliver.
3. If the front angle is less, then it will hold the fibres and create excessive recyling within the carding machine with resulting overcarding and therefore increased fibre damage and nep generation.
4. Lack of parallelisation, fibre damage, nep generation, more flat waste etc. etc., are all consequences of the wrong choice of front angle.
• TOOTH PITCH:
1. Each fibre has a linear density determined by its diameter to length ratio. Fine fibres and long fibres necessitates more control during the carding process. This control is obtained by selecting the tooth pitch which gives the correct contact ratio of the number of teeth to fibre length.
2. Exceptionally short fibres too require more control, in this case , it is not because of the stiffness but because it is more difficult to parallelise the fibres with an open tooth pitch giving a low contact ratio.
• RIB THICKNESS:
1. The rib thickness of the cylinder wire controls the carding "front" and thus the carding power. Generally the finer the fibre, the finer the rib width. The number of points across the carding machine is determined by the carding machine's design, production rate and the fibre dimensions. General trend is towards finer rib thicknesses, especially for high and very low production machines.
2. Rib thickness should be selected properly, if there are too many wire points across the machine for a given cylinder speed, production rate and fibre fineness, "BLOCKAGE" takes place with disastrous results from the point of view of carding quality. In such cases, either the cylinder speed has to be increased or most likely the production rate has to be reduced to improve the sliver quality
• POINT POPULATION:
The population of a wire is the product of the rib thickness and tooth pitch per unit area. The general rule higher populations for higher production rates, but it is not true always. It depends upon other factors like production rate, fineness, frictional properties etc.
• TOOTH POINT:
The tooth point is important from a fibre penetration point of view. It also affects the maintenance and consistency of performance. Most of the recent cylinder wires have the smallest land or cut-to-point. Sharp points penetrate the fibre more easily and thus reduce friction, which in turn reduces wear on the wire and extends wire life.
• BLADE THICKNESS:
Blade thickness affects the fibre penetration. The blade thickness is limited by practical considerations, but the finer the blade the better the penetration of fibres. Wires with thin blade thickness penetrate the more easily and thus reduce friction, which in turn reduces wear on the wire and extends wire life.
• BACK ANGLE:
A lower back angle reduces fibre loading, but a higher value of back angle assists fibre penetration. Between the two extremes is an angle which facilitates both the reduction in loading and assists fibre penetration and at the same time gives the tooth sufficient strength to do the job for which it was designed.
• HARDNESS OF WIRE:
The cylinder wire needs to be hard at the tip of the tooth where the carding action takes place. The hardness is graded from the hard tip to the soft rib. High carbon alloy steel is used to manufacture a cylinder wire and it is flame hardened. Rib should not be hardened, otherwise, it will lead to mounting problems.
• The design or type of clothing, selected for the fibre to be carded is important, but it is fair to
state that within reason, an incorrect design of clothing in perfect condition can give acceptable carding quality whereas a correct clothing design in poor condition will never give acceptable carding quality. There is no doubt that the condition of the clothings is the most important single factor affecting quality at high rates of production. Wire condition and selection of wire are considered to be the two most important factors which influence the performance of modern high production carding machines.
• The condition of the clothing may be defined as the collective ability of the individual teeth of the clothing to hold on to the fibre against the opposing carding force exerted by other teeth acting in the carding direction. For a given design of clothing the condition of the teeth determines the maximum acceptable production rate that can be achieved at the card.
• The speed of the main cylinder of card provides the dynamic force required to work on separating the fibres fed to the card but it is the ability of the carding teeth on the cylinder to carry the fibre forward against the opposing force offered by the teeth of the tops which determines the performance of the card. Increasing cylinder speed increases the dynamic forces acting upon the carding teeth and thus the condition of teeth becomes more important with increased speed. If the condition and design of the cylinder wire is poor, the teeth will not be able to hold onto the fibre through the carding zone, thus allowing some of the freed fibre to roll itself into nep.

DOFFER WIRE:
1. The doffer is a collector and it needs to have a sharp tooth to pickup the condensed mass of fibres circulating on the cylinder. It also requires sufficient space between the teeth to be efficient in fibre transfer from the cylinder, consistent in the transfer rate and capable of holding the fibre under control until the doffer's stripping motion takes control.

2. A standard doffer wire has an overall height of approx. 4.0 mm to facilitate the deeper tooth which must have sufficient capacity to collect all the fibre being transferred from the cylinder to meet production requirements. Heavier webs require a deeper doffer tooth with additional collecting capacity to hanndle the increased fibre mass.

3. The doffer wire's front angle plays a very important part in releasing the fibre from the cylinder wire's influence. A smaller angle has a better chance of enabling the doffer wire's teeth to find their way under the fibres and to secure the fibre's release from the cylinder with greater efficiency. A 60 degree front angle for Doffer has been found to give the optimum performance under normal carding conditions. Too small an angle results in cloudy web and uneven sliver whilst too large an angle results in fibre recirculation and nep generation.

4. Having collected the fibre, it is important for the doffer to retain it until it is stripped in a controlled manner by the doffer stripping motion. The tooth depth, tooth pitch and rib width combine to create the space available for fibre retention within the doffer wire. Thus they directly influence the collecting capacity. If the space is insufficient, fibre will fill the space and any surplus fibre will be rejected. When the surplus fibre is left to recirculate on the cylinder, cylinder loading can take place. Unacceptable nep levels and fibre damage will also result. In severe cases pilling of the fibre will take place.

5. The point of the doffer wire normally has a small land which helps to strengthn the tooth. The extremely small land of around 0.05 mm ensures that the doffer wire height is consistent, has no adverse effect on fibre penetration and is considred essential for efficient fibre transfer from the cylinder. The land has micropscopic striations which are created during manufacturing or grinding. The striations help to collect the fibres from the cylinder and keep them under control during the doffing process.

6. It has been found that a cut-to-point doffer wire penetrates the fibre better than does the landed point wire but is less likely to keep the fibre under control during the doffing process. Sometimes a cut-to-point doffer wire is accompanied by striations along one side of the tooth for this reason. Until recently 0.9mm rib thickness is standardised for doffer wire, regardless of production and fibre characteristics. This rib thickness has been found to give optimum results. However doffer wires with a 0.8mm rib thickness have been introduced for applications involving finer fibres.

7. In general 300 to 400 PPSI(points per square inch) has been found to perform extremely well under most conditions. Doffer wire point population is limited by the wire angle and tooth geometry. Higher population for doffer does not help in improving the fibre transfer.

8. As the production rate rises, the doffer speed also increases. The doffer is also influenced by the centrifugal force, as is the cylinder. But cylinder wire front angle can become closer to counter the effect of centrifugal force, to close the front angle on a doffer wire would reduce its collecting capacity and result in a lowering of the production rate. The solution is to use the wire with striations, which will hold the fibre until the doffer is stripped.

9. The hardness of the doffer wire is a degree lower than that of the cylinder but sufficiently hard to withstand the forces generated in doffing and the resultant wear of the wire. The reason for this slightly lower hardness requirement is the longer and slimmer tooth form of the differ wire.

10. The fibres which are not able to enter the wire will lay on top, i.e. completely out of control. There fore instead of being carded by the tops the fibres will be rolled. Similarly a fibre buried too deep within the cylinder wire will load the cylinder with fibre, weaken the carding action and limit the quantity of new fibres the cylinder can accept. Therefore, the production rate would have to be reduced.

LICKER-IN WIRE:
• Licker-in with its comparatively small surface area and small number of carding teeth, suffers the hardest wear of all in opening the tangled mass of material fed to it.
• Successful action of the Licker-in depends upon a penetrating sharp point rather than a sharp leading edge as with the cylinder wire. Therefore the licker-in wire cannot be successfully restored to optimum performance by grinding.
• The most satisfactory system to adopt to ensure consistent performance is to replace the licker-in wire at regular intervals before sufficient wear has taken place to affect carding quality.
• The angles most widely used are 5 degrees negative or 10 degrees.
• There is no evidence to suggest recommendation of a tooth pitch outside the range of 3 to 6 points per inch.
• It is better to use Licker-in roller without groove. Interlocking wires are used for such type
of licker-ins. This avoids producing the eight precise grooves and to maintain them throughout its life. Interlocking wire is almost unbreakable and thus no threat to the cylinder, tops and doffer in the event of foreigh bodies entering the machine.

FLAT TOPS:
1. The flat tops are an equal and opposite carding force to the cylinder wire and it should be sharp, well maintained and of the correct design.

2. The selection of flexible tops is very much related to the choice of cylinder wire, which in turn is related to the cylinder speed, production rate and fibre characteristics, as previously stated.

3. The modern top is of the semi-rigid type, having flexible foundation and sectoral wire. The points are well backed-off and side-ground to give the necessary degree of fineness. The strength of the top from a carding point of view is in the foundation and is affected by the number of plies and the type of material used. The position of the bend in the wire is determined by stress factors, at around 2:1 ratio along the length of the wire protrusion.

4. The modern top is made from hardened and tempered wire to increase wear resistance , thus improving the life of the flat top.

• Life of the cylinder wire depends upon
1. Material being processed
2. production rate
3. cylinder speed
4. settings

• Wear is the natural and unavoidable side effect of the work done by the vital leading edge of the metallic wire tooth in coping with the opposing forces needed to obtain the carding action which separates fibre from fibre. When the leading edge becomes rounded due to wear, there is a loss of carding power because the point condition has deteriorated to an extent where the leading edge can no longer hold on to the fibre against the carding resistance of the flats. This ultimately leads to fibres becoming rolled into nep with consequent degradation of carding quality. Therefore it is important to recognise that, due to the inevitable wear which takes place during carding, metallic wire must be reground at regular intervals with the object of correctly resharpening the leading edge of each tooth.

• GRINDING:
1. GRINDING A CUT-TO-POINT CYLINDER WIRE:

1. Wire points of cylinder have become finer and the tip is cut-to-point.Because of this new profile, it has beccome necessary to recommend a little or no grinding of the cylinder wire following mounting. TSG grinding machine of GRAF(wire manufacturer) can be used to sharpen these modern wires. TSG grinding is a safe method of grinding.

2. Before grinding , the wire should be inspected with a protable microscope to ascertain the wear. Based on this and the wire point land width, no of traverse for TSG grinding should be decided. If the width of the wire point tip is bigger and the wear out is more, the number of traverse during grinding should be more.
For a new wire, 3 or 4 traverses may be enough. But it may require 10 to 30 traverses for the last grinding before changing the wire, depending upon the maintenance of the wire.

2. GRINDING A NORMAL CYLINDER AND DOFFER WIRE:
1. The first grinding of the metallic wire on the cylinder and doffer is the final and most important step leading up to providing the card with a cylinder in the best possible condition for carding well at maximum production rate. Grinding the lands of the teeth provides the leading edge of each tooth with the final sharpness required for maximum carding power.

2. The first grinding should be allowed to continue until at least eighty percent(for cylinder) and 100% (for doffer) of the lands of the teeth have been ground sufficient to sharpen the leading edge of the tooth.

3. To ascertain this stage of grinding, it is necessary to stop the cylinder regularly and use a simple microscope to examine the teeth at random across and round the cylinder.

4. If the wire on the cylinder is of good quality and has been correctly mounted, the initial grinding period should be completed with in 20 min.

5. It is essential to avoid over-working the wire before taking corrective action. The regrinding cycle must be determined accurately for the conditions applying in the individual mill, by using the microscope.
6. If regrinding is done properly, there are several advantages
1. carding quality will remain consistent
2. There is no risk of overworking the wire
3. Time required for regrinding is very short
4. The exact condition of the clothing is known
5. The working life of the wire is likely to be longer because the points are never allowed to become worn
6-beyond recovery
7. To obtain acceptable grinding conditions at the low grinding speed, the grindstone must always be SHARP, CLEAN and CONCENTRIC. If the grinding stone is gradually allowed to become dull and glazed through constant use, the limited cutting action available will eventually disappear, resulting in burning and hooking of the carding teeth.
8. Due to the low peripheral speed of the grindstone which has to be used, it is most important that the speed of the wire to be ground is as high as is practicable to provide a high relative speed between the grindstone surface and the carding teeth. If wire speed is low, the individual carding tooth spends too long a time in passing under the grindstone, thereby increasing the risk of hooking and burning the tooth, which is usually irreparable.
9. With cylinder grinding, speed is no problem because the normal operating speed of the cylinder is more than sufficient. The speed of the doffer for grinding is more commonly a problem and this should be driven at a minimum speed of 250 m/min, to avoid damage when grinding the wire, the design which is particularly
susceptible to hooking due to the long fine, low angled teeth needed on the doffer.
10. The directions of rotation for metallic wire grinding are normally arranged so that the back edge of the tooth is first to pass under the grindstone. This is termed grinding "back of point"

3. GRINDING FLAT TOPS:
1. Flat tops provide the opposing carding force against the cylinder wire and hence can equally effect carding quality. It is essential to ensure that the tops are kept in good condition to maintain maximum carding power with the cylinder. Again, the only reliable approach is to examine the tops with the microscope and decide whether grinding is required or not.

2. For cards fitted with regrindable tops, it is good practice to regrind the flats at regular intervals thus ensuring that the conditions of the two principal carding surfaces are always complementary one to other.

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The ring spinning will continue to be the most widely used form of spinning machine in the near future, because it exhibits significant advantages in comparison with the new spinning processes.
• Following are the advantages of ring spinning frame

• It is universaly applicable, i.e.any material can be spun to any required count
• It delivers a material with optimum charactersticss, especially with regard to structure and strength.
• it is simple and easy to master
• the know-how is well established and accessible for everyone

• Functions of ringframe

• to draft the roving until the reqired fineness is achieved
• to impart strength to the fibre, by inserting twist
• to wind up the twisted strand (yarn) in a form suitable for storage, transportaion and further processing.

DRAFTING

• Drafting arrangement is the most important part of the machine. It influences mainly evenness and strength
The following points are therefore very important

• drafting type
• design of drafting system
• drafting settings
• selection of drafting elements like cots, aprong, traveller etc
• choice of appropriate draft
• service and maintenance

• Drafting arrangement influence the economics of the machine - directly by affecting the end break rate and indirectly by the maximum draft possible.
• If higher drafts can be used with a drafting arrangement, then coarser roving can be used as a feeding material. This results in higher production rate at the roving frame and thus reducing the number roving machines required, space, personnel and so on.
• In fact increase in draft affects the yarn quality beyond certain limit. Within the limit some studies show that increase in draft improves yarn quality. The following draft limits have been established for practical operation:

• carded cotton- upto 35
• carded blends - upto 40
• combed cotton and blends(medium counts) - upto 40
• combed cotton and blends(fine counts) - upto 45
• synthetic fibres - upto 50

• The break draft must be adapted to the total draft in each case since the main draft should not exceed 25 to 30. It should be noted that higher the break draft, more critical is the break draft setting
• The front top roller is set slightly forward by a distance of 2 to 4mm relative to the front bottom roller, while the middle top roller is arranged a short distance of 2mm behind the middle bottom roller.
• Overhang of the front top roller gives smooth running of the top rollers and shortens the spinning triangle. This has a correspondigly favourable influence on the end break rate.
• Rubber cots with hardness less than 60 degrees shore are normally unsuitable because they can not recover from the deformation caused by the pressure on the top roller while running.
• Soft rubbercots for toprollers have a greater area of contact, enclose the fibre strand more completely and therefore provide better guidance for the fibres.However softer cots wear out significantly faster and tend to form more laps.
• Normally harder rubbercots are used for back top rollers, because the roving which enters the back roller is compact , little twisted and it does not require any additional guidance for better fibre control.
• In the front top roller, only few fibres remain in the strand and these exhibit a tendency to slide apart . Additional fibre guidance is therefore necessary.Therefore rubbercots with hardness levels of the order 80 degrees to 85 degrees shore are mostly used at the back roller and 63 degrees and 65 degrees at the front roller.
• If coarse yarns and synthetic yarns are being spun, harder rubbercots are used at the front roller because of increased wear and in the case of synthetic yarns to reduce lapups.
• Three kinds of top roller weighting(loading) are presently in use

• spring loading
• pneumatic loading
• magnetic weighting

• With pneumatic loading system, the total pressure applied to all top rolers is obtained by simple adjustment of the pressure in the hose using pressure reducing valve. Moreover the rubbercots will not get deformed if the machine is stopped for a longer duration, because the pressure on top rollers can be released to the minimum level.
• The fibre strand in the main drafting field consists of only a few remaining fibres. There is hardly any friction field and fibre guidance provided by the rollers alone is inadequate. Special fibre guiding devices are therefore needed to carry out a satisfactory drafting operation. Double apron drafting arrangements with longer bottom aprons is the most widely used guding system in all the modern ringframes.
• In doube apron drafting system two revolving aprons driven by the middle rollers form a fibre guiding assembly. In order to be able to guide the fibres, the upper apron must be pressed with controlled force against the lower apron. For this purpose, a controlled spacing (exit opening), precisely adapted to the fibre volume is needed between the two aprons at the delivery. This spacing is set by "spacer" or "distance clips". Long bottom aprons have the advantage in comparison wiht short ones, that they can be easily replaced in the event of damage and there is less danger of choking with fluff.
• Spindles and their drive have a great influence on power consumption and noise level in the machine The running characteristics of a spindle, especially imbalance and eccentricity relative to the ring flange, also affect yarn quality and of course the number of end breakage. Almost all yarn parameters are affected by poorly running spindles. Hence it should be ensured that the centering of the spindles relative to the rings is as accurate as possible. Since the ring and spindle form independent units and are able to shift relative to each other in operation, these two parts must be re-centered from time to time. Previously, this was done by shifting the spindle relative to the ring, but now it is usually carried out by adjusting the ring.
• In comparison with Tangential belt drive, the 4-spindle drive has the advantages of lower noise level and energy consumption, and tapes are easier to replace.
• Lappet guide performs the same sequence of movements as the ringrail, but with a shorter stroke, this movement of the guide ensures that differences in the balloon height caused by changes in the ring rail positions do not become too large. This helps to control the yarn tension variation with in control, so that ends down rate and yarn charactersitics are under control.
• Spindles used today are relatively long. The spacing between the ring and the thread guide is correspondingly long, thus giving a high balloon. This has two negative influence

• A high balloon results in large bobbin diameter leading to space problems
• Larger the balloon diameter , higher the air drag on the yarn.This inturn causes increased deformation of the balloon curve out of hte plane intersecting the spindle axis.This deformation can lead to balloon stability, there is increase danger of collapse.

Both these disadvantages result in higher yarn tension, thereby higher endbreaks.In order to avoid this, balloon control rings are used. It divides the balloon into two smaller sub-balloons. Inspite of its large overall height, the double-balloon created in this way is thoroughly stable even at relatively low yarn tension.
• Balloon control rings therefore help to run the mahcine with long spindles(longer lift) and at high spindle speed, but with lower yarn tension. Since the yarn rubs against the control ring, it may cause rougheningof the yarn.
• Most ends down arise from breaks in the spinning triangle, because very high forces are exerted on a strand consisting of fibres which have not yet been fully bound together in the spinning triangle.

RING and TRAVELLER COMBINATION:

• The following factors should be considered
• materials of the ring traveller
• surface charecteristics
• the forms of both elements
• wear resistance
• smoothness of running
• running-in conditions
• fibre lubrication

• For the rings two dimensions are of primariy importance. 1.internal diameter 2. flange width.
• Antiwedge rings exhibit an enlarged flange inner side and is markedly flattened on it upper surface. This type of profile permitted to use travellers with a lower centre of gravity and precisely adapted bow(elliptical travellers), which in turn helped to run the machine with higher spindle speeds. Antiwedge rings and elliptical travellers belong together and can be used in combination.
• Low crown profle has the following advantage. Low crown ring has a flattened surface top
and this gives space for the passage of the yarn so that the curvature of the traveller can also be reduced and the centre of gravity is lowered.In comparison with antiwedge ring, the low crown ring has the advantage that the space provided for passage of the yarn is somewhat larger and that all current traveller shapes can be applied, with the exception of the elliptical traveller. The low crown ring is the most widely used ring form now.
• The ring should be tough and hard on its exterior. The running surface must have high and even hardeness in the range 800-850 vikcers. The traveller hardness should be lower (650-700 vickers), so that wear occurs mainly on the traveller, which is cheaper and easier to replace. Surface smoothness should be high, but not too high, because lubricating film can not build up if it too smooth.

• A good ring in operation should have the following features:

• best quality raw material
• good, but not too high, surface smoothness
• an even surface
• exact roundness
• good, even surface hardness, higher than that of the traveller
• should have been run in as per ring manufacturers requirement
• long operating life
• correct relationship between ring and bobbin tube diameters
• perfectly horizontal position
• it should be exactly centered relative to the spindle

• In reality, the traveller moves on a lubricating film which builds up itself and which consists primarily of cellulose and wax. This material arises from material abraded from the fibres.If fibre particles are caught between the ring and traveller, then at high traveller speeds and with correspondingly high centrifugal forces, the particles are partially ground to a paste of small, colourless, transparent and extremely thin platelets. The platelets are continually being replaced during working. The traveller smoothes these out to form a continuous running surface.The position, form and structure of lubricating film depends on

• yarn fineness
• yarn structure
• fibre raw material
• traveller mass
• traveller speed
• heigh of traveller bow

Modern ring and traveller combination with good fibre lubrication enable traveller speeds upto 40m/sec.
• Traveller imparts twist to the yarn. Traveller and spindle together help to wind the yarn on the bobbin. Length wound up on the bobbin corresponds to the difference in peripheral speeds of the spindle and traveller. The difference in speed should correspond to length delivered at the front rollers. Since traveller does not have a drive on its own but is dragged along behing by the spidle.
• High contact pressure (upto 35 N/square mm)is generated between the ring and the traveller during winding, mainly due to centrifugal force. This pressure leads to generation of heat. Low mass of the traveller does not permit dissipation of the generated heat in the short time available. As a result the operating speed of the traveller is limited.
• When the spindle speed is increased, the friction work between ring and traveller (hence the build up) increases as the 3rd power of the spindle rpm. Consequently if the spindle speed is too high, the traveler sustains thermal damage and fails. This speed restriction is felt particularly when spinning cotton yarns of relatively high strength.
• If the traveller speed is raised beyond normal levels , the thermal stress limit of the traveller is exceeded, a drastic change in the wear behaviour of the ring and traveller ensues. Owing to the strongly increased adhesion forces between ring and traveller, welding takes place between the two. These seizures inflict massive damage not only to the traveller but to the ring as well.Due to this unstable behaviour of the ring and traveller system the wear is atleast an order of magnitude higher than during the stable phase. The traveller temperature reaches 400 to 500 degrees celcius and the danger of the traveller annealing and failing is very great.
• The spinning tension is proportional

• to the friction coefficient between ring and traveller
• to the traveller mass
• to the square of hte traveler speed

and inversely proportional

• to the ring diameter
• and the angle between the connecting line from the traveller-spindle axis to the piece of yarn between the traveller and cop.

• The yarn strength is affected only little by the spinning tension. On the other hand the elongation diminishes with increasing tension, for every tensile load of hte fibres lessens the residual elongation in the fibres and hence in the yarn. Increasing tension leads also to poorer Uster regularity and IPI values.
• If the spinning tension is more, the spinning triangle becomes smaller . As the spinning triangle gets smaller, there is less hairiness.

SHAPE OF THE TRAVELLER:

• The traveller must be shaped to match exactly with the ring in the contact zone, so that a single
contact surface, with the maximum surface area is created between ring and traveller. The bow of the traveller should be as flat as possible, in order to keep the centre of gravity low and thereby improve smoothness of running. However the flat bow must still leave adequate space for passage of the yarn. If the yarn clearance opening is too small, rubbing of the yarn on the ring leads to roughening of the yarn, a high level of fibre loss as fly, deterioration of yarn quality and formation of melt spots in spinning of synthetic fibre yarns.

WIRE PROFILE OF THE TRAVELLER:

• Wire profile influences both the behaviour of the traveller and certain yarn characteristics, they are

• contact surface of the ring
• smooth running
• thermal transfer
• yarn clearance opening
• roughening effect
• hairiness

MATERIAL OF THE TRAVELLER

• The traveller should

• generate as little heat as possible
• quickly distribute the generated heat from the area where it develops over the whole volume of the traveller
• transfer this heat rapidly to the ring and the air
• be elastic, so that the traveller will not break as it is pushed on to the ring
• exhibit high wear resistance
• be less hard than the ring, because the traveller must wear out in use in preference to the ring

• In view of the above said requirements, traveller manufacturers have made efforts to improve the running properties by surface treatment. "Braecker" has developed a new process in which certain finishing components diffuse into the traveller surface and are fixed in place there. The resulting layer reduces temperature rise and increases wear resistance.
• Traveller mass determines the magnitude of frictional forces between the traveller and the ring, and these in turn determine the winding and balloon tension. Mass of the traveller depends upon

• yarn count
• yarn strength
• spindle speed
• material being spun

If traveller weight is too low, the bobbin becomes too soft and the cop content will be low. If it is
unduly high, yarn tension will go up and will result in end breaks. If a choice is available between two traveler weights, then the heavier is normally selected, since it will give greater cop weight, smoother running of the traveller and better transfer of heat out of traveller.
• When the yarn runs through the traveller, some fibres are liberated. Most of these fibres float away as dust in to the atmosphere, but some remain caught on the traveller and they can accumulate and form a tuft. This will increase the mass of traveller and will result in end break because of higher yarn tension. To avoid this accumulation , traveller clearers are fixed close to the ring, so that the accumulation is prevented. They should be set as close as possible to the traveller, but without affecting its movement. Exact setting is very important.
• Specific shape of the cop is achieved by placing the layers of yarn in a conical arrangement. In the winding of a layer, the ring rail is moved slowly but with increasing speed in the upward direction and quickly but with decreasing speed downwards. This gives a ratio between the length of yarn in the main (up) and cross(down) windings about 2:1.
• The total length of a complete layer (main and cross windings together) should not be greater
than 5m (preferably 4 m) to facilitate unwinding. The traverse stroke of the ring rail is ideal when it is about 15 to 18% greater than the ring diameter.
• End break suction system has a variety of functions.
• It removes fibres delivered by the drafting arrangement after an end break and thus prevents mulitple end breaks on neighbouring spindles.
• It enables better environmental control, since a large part of the return air-flow of the aircondition system is led past the drafting system, especially the region of the spinning triangle.
• In modern installations, approx. 40 to 50 % of the return air-flow passes back into the duct system of the airconditioning plant via the suction tubes of pneumafil suction system.
• A relatively high vacuum must be generated to ensure suction of waste fibres
o for cotton - around 800 pascals
o for synthetic - around 1200 pascals
• A significant pressure difference arises between the fan and the last spindle. This pressure difference will be greater , the longer the machine and greater the volume of air to be transported. The air flow rate is normally between 5 and 10 cubic meter/ hour.
• Remember that the power needed to generate an air-flow of 10 cubic meter/ hour , is about 4.5 times the power needed for an air-flow of 6 cubic meter/ hour, because of the significantly higher vacuum level developed at the fan.

SPINNING GEOMETRY:

• From Roving bobbin to cop, the fibre strand passes through drafting arrangement, thread guide, balloon control rings and traveller. These parts are arranged at various angles and distances relative to each other. The distances and angles together are referred to as the spinning geometry,has a significant influence on the spinning opeartion and the resulting yarn. They are

• yarn tension
• number of end breaks
• yarn irregularity
• binding-in of the fibres
• yarn hairiness
• generation of fly etc.
• Spinning Triangle:

Twist in a yarn is generated at the traveller and travel against the direction of yarn movement to the front roller. Twist must run back as close as possible to the nip of the rollers, but it never penetrates completely to the nip because, after leaving the rollers, the fibres first have to be diverted inwards and wrapped around each other. There is always a triangular bundle of fibres without twist at the exit of the rollers, this is called as SPINNING TRIANGLE. Most of the end breaks originate at this point. The length of the spinning triangle depends upon the spinning geometry and upon the twist level in the yarn.
• The top roller is always shifted 3 to 6 mm forward compared to bottom roller. This is called top roller overhang.This gives smoother running and smaller spinning triangle. The overhang must not be made too large, as the distance from the opening of the aprons to the roller nip line becomes too long resulting in poorer fibre control and increased yarn irregularity.
• Continuous variation of the operating conditions arises during winding of a cop.The result is that the tensile force exerted on yarn must be much higher during winding on the bare tube than during winding on the full cop, because of the difference in the angle of attack of the yarn on the traveller. When the ring rail is at the upper end of its stroke, in spinning onto the tube, the yarn tension is substantially higher than when the ring rail is at its lowermost position. This can be observed easily in the balloon on any ring spinning machine.
• The tube and ring diameters must have a minimum ratio, between approx. 1:2 and 1:2.2, in order to ensure that the yarn tension oscillations do not become too great.
• Yarn tension in the balloon is the tension which finally penetrates almost to the spinning triangle and which is responsible for the greater part of the thread breaks. It is reduced to a very small degree by the deviation of the yarn at the thread guide. An equilibrium of forces must be obtained between the yarn tension and balloon tension.

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