page_title: Dry cleaning
section_title: Process
hierarchical_section_title: Dry cleaning / Process
caption_attribution_description: English: modern dry cleaning machine with touchscreen and SPS control, manufacturer EazyClean, type EC124, photo taken prior to installation Deutsch: moderne Trockenreinigungsmaschine mit Touch Screen und SPS Steuerung, Hersteller Eazyclean, Typ EC124, Foto erstellt vor Inbetriebnahme
context_page_description: Dry cleaning is any cleaning process for clothing and textiles using a chemical solvent rather than water. The solvent used is usually tetrachloroethylene. The solvent is called "perc" in the industry and "dry-cleaning fluid" by the public. It is often used instead of hand washing delicate fabrics. People use dry cleaning because it takes less work than hand washing.
context_section_description: A dry-cleaning machine is similar to a combination of a domestic washing machine, and clothes dryer. Garments are placed into a washing/extraction chamber (referred to as the basket, or drum). The chamber is the core of the 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 clothing. The basket can hold between about 10 and 40 kg (20 to 80 lb).
  During the wash cycle, the chamber is filled approximately one-third full of solvent and begins to rotate, agitating the clothing. The solvent temperature is maintained at 30 degrees Celsius (86 degrees Fahrenheit), as a higher temperature may damage it. During the wash cycle, the solvent in the chamber is filtered and then fed back into the chamber. This is known as the cycle and is continued for the wash duration. The solvent is then removed and sent to a distillation unit that has both a boiler and condenser. The condensed solvent is fed into a separator unit where any remaining water is separated from the solvent and then fed into the 'clean solvent' tank. The ideal flow rate is one gallon of solvent per pound of garments (roughly 8 litres of solvent per kilogram of clothing) per minute, depending on the size of the machine.
  Operators also check clothing for foreign objects before placing them into the machine. 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 problem), and will release dye during solvent immersion. Operators will dry clean red clothing separately from lighter-color textiles to avoid color transfer. The solvent used must be distilled to remove impurities that may transfer to clothing. Operators checked clothing for dry-cleaning compatibility, including fasteners. Many fasteners that decorate clothing either are not dry cleaning solvent proof or will not withstand the mechanical action of cleaning. Operators will remove them and restitched them after the cleaning. Or, operators will wrap them in a small padded protector. Fragile items, such as feather bedspreads or tasseled rugs or hangings, may be enclosed in 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.
  Many people believe that all marks or stains can be removed by dry cleaning. Not every stain can be cleaned just by dry cleaning. Some need to be treated with spotting solvents; sometimes by steam jet or by soaking in special stain remover liquids before garments are washed or dry cleaned. Also, garments stored in soiled condition for a long time are difficult to bring back to their original color and texture. Natural fibers such as wool, cotton, and silk of lighter colors should not be left in dirty or soiled condition for long amounts of time as they absorb dirt in their texture and are unlikely to be restored to their original color and finish.
  The main reason that washing in water has a different result than dry cleaning is that water is a polar solvent while dry cleaning uses a non-polar solvent.
  A typical wash cycle lasts for 8–15 minutes depending on the type of garments and degree of soiling. During the first three minutes, solvent-soluble soils dissolve into the perchloroethylene and loose, insoluble soil comes off. It takes approximately ten to twelve minutes after the loose soil has come off to remove the ground-in insoluble soil from garments. Machines using hydrocarbon solvents require a wash cycle of at least 25 minutes because of the much slower rate of solvation of solvent-soluble soils. A dry-cleaning surfactant "soap" may also be added.
  At the end of the wash cycle, the machine starts a rinse cycle wherein the garment load is rinsed with fresh distilled solvent from the pure solvent tank. This pure solvent rinse prevents discoloration caused by s
caption: modern dry cleaning machine with touchscreen and easy interface
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