Glossary of Terms R to T

Rag Filter - A cloth filter (generally terry cloth) located in a water separator to remove moisture from the distilled solvent as it comes from the still and to traces of rancid materials that may have passed through the distillation unit. Rag filters are used almost exclusively in petroleum solvent drycleaning operations since water/solvent separation is not as efficient in these operations.

Reclamation Efficiency - A measure of the efficiency of the reclaiming dryer or drying cycle in extracting solvent from the clothing. Also known as Drying Efficiency.

Reclaimer - A machine used to remove solvent from clothing by tumbling them in a heated air stream. The solvent vapors are then condensed and routed to a water separator, where the solvent is separated from the water. Also known as a Reclaiming Dryer or Recovery Dryer.

Reclaiming Cycle - The first stage in the drying or reclaiming process, in which solvent remaining in the garments is vaporized by a stream of hot air. The vapors are then condensed and the liquid solvent drawn off and stored for reuse.

Reclaiming or Recovery Dryer - See Reclaimer.

Recovery Unit - See Reclaimer.

Recycle - A process of preparing a solvent for re-use. In drycleaning, this is done by filtering and distilling the drycleaning solvent after it has removed the soil from the clothes. Solvent can be recycled repeatedly by a drycleaner.

Redeposition - The return of insoluble soil to the fabrics from which it was freed during the cleaning cycle. Dispersal and redeposition of insoluble soils is the principal cause of “graying”.

Reducing Bleach - A bleach that decolorizes stained or soiled areas through a reducing reaction. Examples of reducing bleaches are: sodium bisulfite, sodium hydrosulfite, titanium stripper and oxalic acid.

Refrigerated Condenser - A vapor recovery system into which an air-solvent gas-vapor stream is routed and the solvent is condensed by cooling the gas-vapor stream. Refrigerated condensers recover solvent emissions by chilling the air stream below the solvent’s dew point, causing the solvent and water vapor to condense. Refrigerated condensers can be placed either in the air stream near the end of the drying cycle or at the final exhaust point of the process. In transfer machines equipped with refrigerated condensers, the air stream received from the washer when the door is opened is typically vented to the atmosphere after one pass through the condenser. Thirty percent of the solvent is typically recovered. Vapors from the drying unit are continually routed back to the dryer after passing through the condenser until the drying cycle ends. Eighty-five percent of the remaining solvent is typically recovered. Unrecovered vapors are vented to the atmosphere when the dryer is opened. In vented, dry-to-dry machines equipped with refrigerated condenser, emissions occur when the door is opened. No-vent or closed-loop machines do not vent to the atmosphere and have the highest efficiency in recovering emissions. Also known as a Chiller.

Refrigerated Condenser Coil - The coil containing the chilled gas (usually CFC 11 or CFC 12) used to cool and condense the solvent.

Regenerative Filters - The most widely used type of powder filtration system. It consists of flexible tubes that are constructed of braided metal wire, metal helical springs or braided knit fibers. The filter powder, which is the filter media, is held by the flexible tubes. Spent powder is removed or “bumped” and then the regenerated or pre-coated each day or after each load has been run. Also known as Flexible Tube Filters or Bump Action Filters.

Rigid Tube Filter - A type of non-regenerative filter in which the precoat is supported on an internal wire frame surrounded by a filter screen. Backwashing is used to remove the filter cake from these filters.

Room Enclosure - Stationary structure that encloses a transfer machine system. These enclosures are designed to contain solvent vapors which are vented to a carbon adsorber or an equivalent control device during operation on the transfer machine system.

Rynex - A drycleaning solvent that is composed of dipropylene glycol tertiary-butyl ether. It has a flash point of 203° F and a specific gravity of less than 0.95.

Rynex III - Rynex III is a more recent formulation of the drycleaning solvent Rynex. It is a mixture of glycol ethers more specifically dipropylene glycol tert-butyl ether or DPTB.

Screen Filters - Fine mesh screen held in a vertical plane with nipples that feed into a manifold. Screen Filters are used in powder filtration systems. The solvent surrounds the screens where the powder collects and strains insolubles out as the solvent flows through and into the manifold and out. A variation of this type of filter employs a series of horizontal circular screens between each of which is a brush which automatically rotates for cleaning. This filter operates with a blend of sweetener powder and carbon and is automatic in its dispensing of powders and self cleaning. Very few screen filters are in use today.

Second Generation Drycleaning Machine - See Vented Dry-to-Dry Machine.

Separator Water - Wastewater generated from the physical separation of drycleaning solvent and water in a water separator. Separator water is a contact water and therefore contains solvent.

Shell Sol 140 HT - A high flash point petroleum solvent (flash points 145° F) manufactured by Shell Chemical Company. Shell Sol 140 HT is composed of a mixture of C9 and C12 hydrocarbons.

Sixth Generation Machine - A term used by some to refer to dry-to-dry machines that utilize GreenEarth drycleaning solvent.

Sizing - A type of finish used in drycleaning to impart body to a fabric. Most sizing used in drycleaning operations is composed of hydrocarbon resins and comes in either a solid form (powder or beads) or a liquid. In its liquid form the sizing is generally combined with a petroleum naphtha carrier. Anti-static agents and optical brighteners are commonly added to sizing.

Slide Board – A metal-lined chute utilized in a transfer machine operation to transfer clothing from a washer to an extractor.

Sludge - See Still Bottoms.

Sniffer - See Carbon Adsorber.

Sodium Bisulfite - A reducing bleach used in pre-cleaning and spotting operations. Its main use is in removing the last traces of chlorine bleach.

Sodium Hydrosulfite - A reducing bleach used in pre-cleaning and spotting operations.

Sodium Hypochlorite - The most commonly used oxidizing bleach. It is normally packaged as a 5% solution but is used in pre-cleaning and spotting operations in a 1% solution. Sodium Hypochlorite is also widely used in conventional laundry operations.

Sodium Perborate - A common oxidizing bleach used in pre-cleaning and spotting operations . It is a highly alkaline substance and is normally neutralized with acetic acid after application.

SolvairTM Drycleaning System - A closed-loop drycleaning process which uses SolvairTM Fluid or dipropylene glycol n-butyl ether (dipropylene glycol normal butyl ether) as a base cleaning fluid and then uses liquid carbon dioxide to rinse the garments.

Solvation Process - A solvent vapor recovery process in which an air stream is continuously circulated through the drycleaning machines condenser, a water bath and the hot clothes in the machine’s tumbler. When passing through the water bath, the air stream becomes saturated with water. The perc and water in the air stream leaving the stream becomes saturated with water. The perc and water in the air stream leaving the bath form an azeotrope, which has a lower boiling point than perc alone, thereby increasing the ability of the machines standard condenser to recover the solvent vapor.

Solvent Mileage - The amount of fabric cleaned per a quantity of solvent; a measure of the efficiency of a drycleaning system. Also known as Solvent Consumption.

Solvent Pump - A pump located in the drycleaning machine that circulates solvent in the machine.

Solvent Relative Humidity - The moisture content of drycleaning solvent with added detergent is expressed as a percentage of the amount of water carried by the detergent in the solvent compared with the maximum amount of water which the detergent in the solvent will carry.

Solvent Relative Humidity Instrument - A moisture control device that collects solvent, air, and moisture vapors from the wash wheel, passes them over a sensing element that measures solvent relative humidity, and automatically injects water in the washer when the relative humidity drops below a pre-determined setting.

Solvent Stabilizers - Chemicals added to solvents to prevent solvent degradation. Stabilizers are predominantly “acid acceptors” that prevent solvents from becoming acidic and therefore corrosive. Generally solvent stabilizers comprise no more 0.2 % (by volume) of the solvent/stabilizer mixture. Some of the stabilizers that have been added to perchloroethylene drycleaning solvent include: cyclohexene oxide, beta-ethoxy proprionitrile, n-methyl morpholine, 4-methoxyphenol, tripropylene, and benzotriazole.

Solvent Turnover - Total gallons of distilled solvent that must be replaced to the system for each 100 pounds of fabric cleaned.

Spin Disk Filter - A device containing 36 fifteen-inch diameter disks of polyester fine mesh material mounted on a hollow central shaft with a motor drive to spin the shaft. Solvent enters the center housing through the hollow central shaft. The filter can utilize either filter powder or to be powderless. Also known as a Centrifugal Disc Filter.

Spot Bleaching - The use of a bleach in pre-cleaning or spotting operations. Spotting or Pre-spotting - The selective application of chemicals, steam, detergent and/or water to loosen or remove specific stains from soiled garments. Spotting is sometimes done prior to drycleaning (pre-spotting or pre-cleaning) but may also be necessary following drycleaning to remove stubborn stains. Also known as Pre-cleaning.

Spotting Board - A work surface for pre-cleaning and spotting work. The spotting board is normally supplied with steam, compressed air and water.

Spotting Agent - A chemical used to clean or bleach stained or heavily soiled areas on clothing. Spotting agents are generally divided into three classifications: dry-side agents (used to clean non-water soluble stains or soiled areas), wet-side agents for water soluble stains or soils, and bleaches which oxidize or reduce stains or soiled areas.

Standard Cartridge Filter - A cartridge filter (carbon core, all carbon or carbonless) that has dimensions of 7 5/8 inches by 14 1/4 inches.

Steam Cabinet - See Drying Cabinet.

Steam Press - A machine used in the finishing process that utilizes steam to press clothing after it has been drycleaned. A steam line from the boiler supplies steam to the press. The garment is held in place on the press by means of a partial vacuum generated by a vacuum unit. The garment is pressed by lowering the press on the garment and pressing a foot pedal that releases the steam. The condensed steam is evacuated by the vacuum unit. See Grid-Head Press and Hot-Head Press.

Steam Stripping - A method to extract additional solvent from distillation residues during the distillation process. In this method, steam is injected directly into the distillation residues in the still. This causes the boiling point to drop and the distillation rate to increase.

Steam Sweeping - A technique used during the final stage of still boil down to recover as much solvent as possible. In this technique, live steam is swept across the still just above the liquid residue. This results in a temperature increase and a resulting additional recovery of solvent.

Still - A device used to volatilize and recover solvent from contaminated solvent.

Still Bottoms - 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 drycleaning operations are hazardous wastes. Also known as Distillation Bottoms, Distillation Residues, Still Residues or Sludge.

Still Kettle - The vessel in which the distillation process occurs. Still Residues - See Still Bottoms.

William Joseph Stoddard - (1878 - 1940). An American drycleaner from Atlanta who worked with the petroleum refining industry to develop a higher flash petroleum drycleaning solvent (now referred to as Stoddard solvent) in 1924. Stoddard Solvent - A petroleum drycleaning solvent which is a blend of petroleum distillate fractions (C7 - C12). It is composed of 30 - 50% straight and branched chain alkanes, 30 - 40% cycloalkanes, and 10 - 20% alkyl aromatic hydrocarbons.

Streaks - See Swale.

Surfactant - The term surfactant is short for "surface active agent". It is a chemical that stabilizes mixtures of oil and water by reducing the surface tension at the interface of oil and water molecules. The addition of a surfactant prevents an oil/water mixture from separating into layers.

Suzie - A device that blows steam and air through a garment to reduce wrinkling and facilitate pressing and finishing. Also known as Form Finisher.

Swale - Uneven deposit of non-volatile material on a garment. Also known as Streaks.

Sweetener Powder - A type of filter powder that is composed of activated clay. These clays are adsorptive and will remove soluble impurities from solvent such as detergents, fatty acids and dyes. This powder has been used with filter powder to avoid filter clogging.

Synthetic Detergents - A liquid or solid material able to dissolve oily materials and disperse them or emulsify them in water.