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Encyclopedia > Dry cleaning

Dry cleaning is any cleaning process for clothing and textiles using an organic solvent other than water — generally known as dry cleaning fluid, and typically this is tetrachloroethylene. Dry cleaning is necessary for cleaning items which would otherwise be damaged by water and soap or detergent. It may also be sought if washing by hand — another alternative for some delicate fabrics — is seen as laborious. Clothing protects the vulnerable nude human body from the extremes of weather, other features of our environment, and for safety reasons. ... Sunday textile market on the sidewalks of Karachi, Pakistan. ... A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Tetrachloroethylene Cl2C=CCl2 is a manufactured chemical compound that is widely used for the dry cleaning of fabrics and for metal-degreasing. ... Tetrachloroethylene Cl2C=CCl2 is a manufactured chemical compound that is widely used for the dry cleaning of fabrics and for metal-degreasing. ... This article is about the computer protocol. ... Laundry detergents are just one of many possible uses for detergents Detergent is a compound, or a mixture of compounds, intended to assist cleaning. ...

Contents

History

Dry cleaning uses non-water-based solvents to remove dirt and stains from clothes. The potential for using petroleum based solvents in this manner was first discovered in the mid-19th century by French dye-works owner Jean Baptiste Jolly, who noticed that his tablecloth became cleaner after his maid spilled kerosene on it, and from this observation developed a service to clean other people's clothes in this manner, which he termed "nettoyage à sec," or "dry cleaning" in English.[1] A solvent is a liquid that dissolves a solid, liquid, or gaseous solute, resulting in a solution. ... Pumpjack pumping an oil well near Lubbock, Texas Ignacy Łukasiewicz - inventor of the refining of kerosene from crude oil. ... Kerosene or paraffin oil (British English, not to be confused with the waxy solid also called paraffin wax or just paraffin) is a colorless flammable hydrocarbon liquid. ...


Early dry cleaners used petroleum-based solvents, such as gasoline and kerosene. Concerns over flammability led William Joseph Stoddard, a dry cleaner from Atlanta, to develop Stoddard solvent as a slightly less flammable alternative to gasoline-based solvents. The use of highly flammable petroleum solvents led to many fires and explosions, which resulted in heavy regulation of dry cleaners. Gasoline or petrol is a petroleum-derived liquid mixture consisting mostly of hydrocarbons and enhanced with benzene or iso-octane to increase octane ratings, used as fuel in internal combustion engines. ... This article is about the state capital of Georgia. ... White spirit, also known as Stoddard solvent, is a paraffin-derived clear, transparent liquid which is a common organic solvent used in painting and decorating. ... Flammable or Flammability refers to the ease at which a substance will ignite, causing fire or combustion. ...


After World War II, dry cleaners began using various chlorinated solvents. These solvents were much less flammable than petroleum solvents and had much greater cleaning power. By the mid-1930s the dry cleaning industry had adopted tetrachloroethylene (perchloroethylene) as a standard, colloquially called "perc," as the ideal solvent. It is stable, nonflammable, and has excellent cleaning power and is gentle to most garments. Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Tetrachloroethylene Cl2C=CCl2 is a manufactured chemical compound that is widely used for the dry cleaning of fabrics and for metal-degreasing. ...


Process

A dry cleaning machine is somewhat similar to combination of a domestic washing machine, and clothes dryer. Garments are placed into a washing/extraction chamber (referred to as the basket, or drum). This is the core of the dry cleaning machine. The washing chamber contains a horizontal, perforated drum that rotates within an outer shell. The shell holds the solvent while the rotating drum holds the garment load. Depending on the size of the machine the basket capacity will be between 20 and 80 lb (9-36 kg) of garments. Front-loading washing machine. ... An electric clothes dryer A clothes dryer or tumble dryer is a major household appliance that is used to remove the residual moisture from a load of clothing and other textiles, generally shortly after they are cleaned in a washing machine. ...


During the wash cycle the chamber is filled approximately 1/3 full of solvent and begins to rotate to agitate the clothing. The solvent temperature is controlled at 85°F (29.4°C), as a higher temperature may extract dye from the garments, causing color loss. During the wash cycle, the chamber is constantly fed a supply of fresh solvent from the working solvent tank while spent solvent is removed and sent to a filter unit comprising a distillation boiler and condenser. The ideal flow rate is one gallon of solvent per pound of garments per minute, depending on the size of the machine. Look up dye in Wiktionary, the free dictionary. ... Distillation is a means of separating liquids through differences in their boiling points. ... Look up condenser in Wiktionary, the free dictionary. ...


Before being placed in the machine, garments are inspected for stains and soils by the operator. Depending on the nature of the soil, a catalyst may be applied to the soil; this depends on the operator's judgement of the makeup of the textile and the soil itself. Oil-based soils such as grease, oil or lipstick typically are removed very well by perchloroethylene, whereas water-based soils such as coffee, wine and perspiration will need a catalyst to allow the dry cleaning solvent to emulsify and lift them. Food based grease soils fall in between the two, and a milder catalyst may be applied. Look up grease in Wiktionary, the free dictionary. ... Natural olive oil Synthetic motor oil An oil is any substance that is in a viscous liquid state (oily) at ambient temperatures or slightly warmer, and is both hydrophobic (immiscible with water, literally water fearing) and lipophilic (miscible with other oils, literally fat loving). This general definition includes compound classes... Lipstick is a cosmetic product containing pigments, oils, waxes, and emollients that applies color and texture to the lips. ... A cup of coffee Workers sorting and pulping coffee beans in Guatemala Coffee is a widely consumed beverage prepared from the roasted seeds — commonly referred to as beans — of the coffee plant. ... A glass of red wine This article is about the alcoholic beverage. ... Sweating (also called perspiration or sometimes transpiration) is the loss of a watery fluid, consisting mainly of sodium chloride and urea in solution, that is secreted by the sweat glands in the skin of mammals. ... It has been suggested that this article or section be merged into Catalysis. ...


Garments are also checked carefully for foreign objects; items such as plastic pens will dissolve in the solvent bath and may damage textiles beyond recovery. Some textile dyes are "loose" (red being the main culprit), and will shed dye during the solvent immersion; these will not be included in a load along with lighter-based coloured textiles to avoid colour transfer. In addition, the solvent used must be distilled to remove any impurities which may transfer to the clothes. Garments are checked carefully for dry cleaning textile compatibility, including the fasteners; many decorative fasteners are either not dry-cleaning-solvent proof, or will not withstand the mechanical action of the cleaning cycle. These will be removed and restiched after the cleaning, or protected with a small padded protector as needed. Finally, fragile items such as feather bedspreads or tasselled rugs or hangings may be enclosed into a loose mesh bag. The density of perchloroethylene is around 1.7 g/cm3 at room temperature (70% heavier than water), and the sheer weight of absorbed solvent may cause the textile to fail under normal force during the extraction cycle unless the mesh bag provides mechanical support. Fn represents the normal force. ...


A typical wash cycle lasts for 8-15 minutes depending on the type of garments and amount of soiling. During the first three minutes, solvent-soluble soils dissolve into the perchloroethylene and loose, insoluble soil from fabrics comes off. It takes approximately ten to twelve minutes after the loose soil has come off to remove all of the ground-in insoluble soil from the garments. Machines using hydrocarbon solvents require a much longer wash cycle of at least 25 minutes because of the much slower rate of solvation of solvent-soluble soils (e.g oily stains). A dry-cleaning surfactant "soap" may also be added.


At the end of wash cycle, the machine starts a rinse cycle and the garment load is rinsed with fresh distilled solvent from the pure solvent tank. This pure solvent rinse prevents discoloration of garments caused by soil particles being absorbed back onto the garment surface from the "dirty" working solvent.


After the rinse cycle the machine begins the extraction process. This process recovers dry cleaning solvent for reuse. Modern dry cleaning machines can recover approximately 99.99% of the solvent used in the cleaning process.


The extraction begins by draining the solvent out of the washing chamber cycle and accelerating the basket to speeds of 350 to 450 rpm, causing much of the solvent to spin free of the fabric. When no more solvent can be spun out, the machine starts its drying cycle.


During the drying cycle the garments are tumbled in continuous stream of warm air (145°F/63°C) that circulates through the basket evaporating any traces of solvent left behind after the spin cycle. The temperature of the air is carefully controlled to prevent over drying and heat damage to the garments. The warm air then passes through a chiller unit where the solvent vapors are condensed, and returned to the distilled solvent tank. Modern dry cleaning machines use a closed loop system where the chilled air is then reheated and recirculated. This results in very high solvent recovery rates.


After the drying cycle is completed, a deodorizing (aeration) cycle starts to cool the garments and remove the last traces of dry cleaning solvent, by circulating cool outside air over the garments and then through a vapor recovery filter made from activated carbon and polymer resins. At the end of the aeration cycle, the dry cleaned garments are clean, odorless and ready for pressing/finishing.


Solvent processing

Working solvent from the washing chamber passes through several filtration steps before it is returned to the washing chamber. The first step is a button trap which prevents small objects (lint, fasteners, buttons, coins etc) from entering the solvent pump. In chemistry, alchemy and water treatment, filtration is the process of using a filter to mechanically separate a mixture. ...


Next the solvent passes through a filter unit which removes lint and insoluble suspended soils from the solvent. Several different types are used, most filters use an ultra fine mesh to support a thin layer of filter powder (made from diatomaceous earth and activated clays). Some machines use powderless filters which are capable of removing soil particles greater than 30 micrometers from the solvent. Lint is the name of a Wolf that used to Bum other wolfs while Grey ctas filmed them with thier camera Phones. ... A sample of diatomaceous earth Diatomaceous earth (IPA: , also known as DE, diatomite, diahydro, kieselguhr, kieselgur and Celite) is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ... A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ...


As the machine is used, a thin layer of filter cake (called muck) accumulates on the surface of the lint filter. The muck is removed regularly (once per day) and then further processed to recover any solvent trapped in the muck. Many machines use "spin disc filters" in which the muck is removed from the filter surface by centrifugal action while the filter is back-washed with solvent. A filter cake is formed by the substances that are retained in or on a filter (depending on whether a depth or a surface filter is used). ...


After passing through the lint filter, the solvent passes through an adsorptive cartridge filter. This filter is made from activated clays and charcoal and removes fine insoluble soil and non-volatile residues along with dyes from solvent. Finally the solvent passes through a polishing filter which removes any traces of soil not removed by the previous filters. The clean working solvent is then returned to the working solvent tank. Adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorbate). ...


To enhance cleaning power, small amounts of detergent (0.5%-1.5%) are added to the working solvent and are essential to its functionality. These detergents help dissolve hydrophilic soils and keep soil from redepositing on garments. Depending on the machine's design, either an anionic or cationic detergent is used. Laundry detergents are just one of many possible uses for detergents Detergent is a compound, or a mixture of compounds, intended to assist cleaning. ... Hydrophile, from the Greek (hydros) water and φιλια (philia) friendship, refers to a physical property of a molecule that can transiently bond with water (H2O) through hydrogen bonding. ...


Dry cleaning wastes

Cooked muck

Cooked Powder Residue — the waste material generated by cooking down or distilling muck. Cooked powder residue is a hazardous waste and will contain solvent, powdered filter material (diatomite), carbon, non-volatile residues, lint, dyes, grease, soils and water. This material should then be disposed of in accordance with local laws. This article describes hazardous waste as a substance; for the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal see Basel Convention // Put simply, a Hazardous waste is waste that poses substantial or potential threats to public health or the environment and generally exhibits one...


Sludge

The waste sludge or solid residue from the still. Still bottoms contain solvent, water, soils, carbon and other non-volatile residues. Still bottoms from chlorinated solvent dry cleaning operations are hazardous wastes.


Environment

Perchloroethylene is toxic, and some believe that long-term exposure can cause liver and kidney damage, though no study has conclusively proven that. There are other solvents including:

  • Wet Cleaning — This is a system that uses water and biodegradable soap. Computer-controlled dryers and stretching machines ensure that the fabric retains its natural size and shape. Wet cleaning is claimed to clean a majority of "dry clean only" garments safely, including leather; suede; most tailored woolens, silks and rayons. (Neckties seem to be the one exception.)
  • Silicone and Liquid CO2 Solvents — Relatively new approaches to dry cleaning have been developed based on both liquid carbon dioxide and silicone. Dry cleaners using these solvents are currently few in number. The main difficulty with liquid CO2 is the need to operate the machine at pressures over 73 ATM (1073 psig), requiring an exceptionally strong and well-sealed wash chamber. For example, a washer access door just 12 inches in diameter will have over 30 tons of pressure pushing out on it.
  • Alternative Petroleum Solvents — This is more like standard dry cleaning, but the processes use alternative hydrocarbon solvents such as Exxon DF-2000 or Chevron-Phillips' EcoSolv. Alternative solvents are less aggressive than perc and require a longer cleaning cycle. While flammable, these solvents do not present a high risk of fire or explosion when used properly.

Biodegradation is the decomposition of material by microorganisms. ... Rayon is a manufactured regenerated cellulosic fiber. ... Silicones (more accurately called polymerized siloxanes or polysiloxanes) are inorganic-organic polymers with the chemical formula [R2SiO]n, where R = organic groups such as methyl, ethyl, and phenyl. ... Carbon dioxide pressure-temperature phase diagram Supercritical carbon dioxide refers to carbon dioxide with some unique properties. ... Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ...

Solvents used

Modern

  • Perchloroethylene — Most common solvent, known more commonly as "Perc", the "standard" for cleaning performance, and most aggressive cleaner (use caution, may cause color bleeding/loss, especially at higher temperatures).
  • High flash point hydrocarbons DF-2000 (140°F/60°C flash point) — Slightly less flammable and explosive than Stoddard solvent, not as effective as perchloroethylene.
  • Modified hydrocarbons blends (Pure Dry)
  • Glycol ethers (dipropylene glycol tertiary-butyl ether) (Rynex) — not as effective as perchloroethylene.
  • Cyclic Silicone decamethylcyclopentasiloxane, GreenEarth (170.6 °F/77 °C flash point) — not as effective as perchloroethylene. Requires a license be obtained to utilize the property of GreenEarth Cleaning. Degrades within days in the environment to SiO2 (sand), CO2 (carbon dioxide), and H2O (water). Slightly less flammable and explosive than Stoddard solvent. Toxicity tests by Dow Corning shows the solvent to increase the incidence of tumors in female rats. The USEPA has stated that these findings may indicate that there is a potential carcinogenic hazard. As of 2004, South Coast Air Quality Management District funding for silicone-based solvents (i.e., GreenEarth) has been suspended.
  • Liquid CO2Consumer Reports rated this method superior to even conventional methods; machinery is very expensive. Most cleaners with these machines keep traditional machines on-site for the heavier soiled textiles. Not good for use on smoke or water damaged textiles.

Tetrachloroethylene Cl2C=CCl2 is a manufactured chemical that is widely used for the dry cleaning of fabrics and for metal-degreasing. ... White spirit, also known as Stoddard solvent, is a paraffin-derived clear, transparent liquid which is a common organic solvent used in painting and decorating. ... Ethylene glycol (IUPAC name:ethane-1,2-diol) is a chemical compound widely used as an automotive antifreeze (coolant). ... Ether is the general name for a class of chemical compounds which contain an ether group — an oxygen atom connected to two (substituted) alkyl groups. ... Silicones (more accurately called polymerized siloxanes or polysiloxanes) are inorganic-organic polymers with the chemical formula [R2SiO]n, where R = organic groups such as methyl, ethyl, and phenyl. ... The South Coast Air Quality Management District (SCAQMD) was formed in 1976 and is the air pollution agency responsible mainly for regulating stationary sources of air pollution for most of Los Angeles, San Bernardino, Riverside county, and all of Orange county. ... Carbon dioxide pressure-temperature phase diagram Supercritical carbon dioxide refers to carbon dioxide with some unique properties. ... Consumer Reports, an American magazine published monthly by Consumers Union, publishes reviews and comparisons of consumer products and services based on reporting and results from its in-house testing laboratory. ...

Historical

White spirit, also known as Stoddard solvent, is a paraffin-derived clear, transparent liquid which is a common organic solvent used in painting and decorating. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... R-phrases , , , , S-phrases , , , , , Flash point non flammable RTECS number FG4900000 Supplementary data page Structure and properties n, εr, etc. ... The chemical compound 1,1,1-trichloroethane is a chlorinated hydrocarbon that was until recently widely used as an industrial solvent. ... For other uses, see CFC (disambiguation). ...

References

  1. ^ How Dry Cleaning Works. Retrieved on 2006-03-30.

For the Manfred Mann album, see 2006 (album). ... March 30 is the 89th day of the year in the Gregorian calendar (90th in leap years). ...

See also

Martinizing Dry Cleaning is a dry cleaning franchise founded in 1949. ... This is a list of topics related (in whole or in part) to (a) phenomena in the natural environment which have a definite or significantly possible connection with human activity or (b) features of human activity which have a definite or significantly possible connection with the natural environment, even if...

External links


  Results from FactBites:
 
IFI Ask the Expert: What is Drycleaning (765 words)
dry cleaning is not the answer to all soil and stain removal problems.
After the cleaning cycle, the solvent is drained and an *extract* cycle is run to remove the excess solvent from the clothes.
The length of the cleaning cycle is dependant upon the type of article cleaned and the degree of soiling.
Dry cleaning - Wikipedia, the free encyclopedia (1930 words)
By the mid-1930s the dry cleaning industry used tetrachloroethylene (perchloroethylene) as a standard, coloquially called "perc," as the ideal solvent.
A dry cleaning machine is somewhat similar to combination of a domestic washing machine, and clothes dryer.
After the drying cycle is completed, a deodorizing (aeration) cycle starts to cool the garments and remove the last traces of dry cleaning solvent, by circulating cool outside air over the garments and then through a vapor recovery filter made from activated carbon and polymer resins.
  More results at FactBites »

 
 

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