US 20020184715 A1
An improved dry cleaning apparatus and method for the non-aqueous cleaning of fabric materials comprises the introduction of steam into a dryer chamber containing fabric materials previously washed in a non-aqueous organic cleaning solvent such as perchloroethylene. The steam is heated at a sufficient temperature for a duration of time, both of which are determined by the type of fabric and solvents involved. The heated steam volatilizes any excess cleaning solvent contained in or on said fabric creating a gaseous water/solvent mixture which is then subsequently separated from the fabric materials. The gaseous mixture can be condensed, its component parts separated and re-used in the cycle again.
1) A method for the cleaning of fabric wherein a non-aqueous organic cleaning solvent is used to clean said fabric further comprising the application of steam to said fabric during the drying cycle.
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6) An improved dry cleaning apparatus for the non-aqueous cleaning of fabric materials comprising:
a) an internal drying chamber;
b) a steam source;
c) a conduit for the introduction of said steam into said drying chamber; and
d) an exit means for the removal of said steam from said drying chamber.
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 The invention relates generally to methods for dry cleaning textiles and clothing. More specifically, the present invention relates to a dry cleaning apparatus and modifications thereto which removes excess dry cleaning solvent from the system and is thereby more environmentally friendly.
 Dry cleaning of textiles and, in particular, fine clothing is a well known process in which the garment is immersed in a cleaning solvent other than water which loosens any dirt, grease or grime from the fibers of the garment fabric which is then, in one way or another, evaporated off. There are any number of different solvents and methods for doing this.
 In conventional dry cleaning systems, the effluent vapors or fumes of the solvent such as perchlorethylene (PERC) emanating from the dry cleaning washing machine and dryers generally are vented directly to the atmosphere and thus pollute the atmosphere. By being so vented, they are also lost for reuse. Thus, the escaping vapors not only produce an environmental hazard, but their loss is extremely costly to the dry cleaning establishment.
 Attempts have been made to remove the solvent vapor contained in the air-stream through a bed of activated carbon. The carbon absorbs the solvent vapor or gas held in the air-stream, allowing the thus cleaned air to pass through the carbon bed to atmosphere. See U.S. Pat. Nos. 3,203,110 and 3,538,615 to Fuhring et al. Unfortunately, the carbon bed will only absorb approximately one gallon of solvent per 80 lb. of carbon before becoming saturated with solvent vapor, and must then be de-absorbed by passing a “blanket” of steam through the carbon bed in a reverse direction to that of the absorption flow. The steam and solvent vapors form an azeotrope which must then be condensed, and the resultant water and liquid solvent must be separated according to their specific gravities. Thereafter, the solvent may then be recycled for reuse.
 U.S. Pat. No. 4,622,039 to Merenda discloses and claims a method and means to recapture the cleaning solvent and to reuse the same so that as a result thereof, the solvent is not vented to the atmosphere and thus pollution of the atmosphere is avoided. A dry cleaning washer and a dryer are arranged in a closed cycle system so that the effluent solvent vapor from the washer is delivered to an accumulator chamber simultaneously with the delivery from the dryer of effluent hot air. The hot air superheats the solvent vapor thereby increasing its volatility and the heated and highly volatile solvent vapor is then passed to a condenser which contains feed coils for supplying clean air to the dryer. In passing through the condenser, the superheated solvent vapor instantly liquifies giving off its heat to the cool air, thus pre-heating the clean air prior to its entry into the dryer. The liquified solvent is returned to the washer, or to a storage reservoir.
 U.S. Pat. No. 3,951,597 to Mooring discloses and claims a method of dry cleaning fabrics, draperies or clothing, in situ, by forcefully infusing the fabric in the open atmosphere with special fast-acting, versatile dry cleaning solvent so as to dissolve and suspend various stains and soils in the fabric, even though firmly set due to age. Ambient air is promptly drawn in and droplets of soil-laden solvent is promptly drawn therethrough by suction into a closed waste and suction chamber where the soil is deposited in the form of a sludge, while the carrier air and solvent is discharged to the atmosphere. A special, highly effective, fast-acting, non-flammable and non-toxic solvent such as methylene chloride, trichloro-ethylene is useful for these purposes.
 U.S. Pat. No. 4,086,705 to Wehr discloses a dry cleaning apparatus wherein petroleum solvent vapors which are discharged from a dry cleaning dryer in a heated gaseous mixture of vapors and air are condensed and recovered, and heat energy is recovered for productive use elsewhere. The gaseous mixture of vapors and air is sprayed with relatively cool water to condense the solvent vapors. The resulting liquid mixture of water and solvent is withdrawn from the spray chamber and is subjected to gravitational separation. Water reclaimed in the separation process is reused in the spray chamber. Recovered solvent is reused in a dry cleaning washer. The gravitational separation process is preferably carried out in a series of gravitational separators, and heat is withdrawn from at least one of the separation units for productive use in a heat-consuming device.
 U.S. Pat. No. 3,807,948 to Moore teaches a method of dry cleaning of goods in which the majority of the solvent present in the goods at the conclusion of the actual cleaning is recovered by circulating air, by means of a fan, through the goods in a dry cleaning drum and through a water-cooled condenser and a heating element. A small remaining amount of solvent is removed from the goods by a deodorizing operation, in which air is passed in a closed circuit through the goods in the dry cleaning drum and over a refrigerated surface on which the solvent is condensed.
 Finally, U.S. Pat. No. 3,928,660 to Alderson et al., discloses a dry cleaning finishing method and apparatus for use in combination with a steam clothes press for mixing and pressurizing a liquid so that it can be easily applied to garments being pressed. The apparatus comprises a supply tank that meters the liquid material into a pressure tank. Steam condensate is mixed with steam from the clothes press and this provides the chemically pure water, heat and pressure to the pressure tank that mixes with the sizing concentrate and forces the water-sizing mixture to a spray gun for use when needed or desired by the pressman.
 All of the aforementioned dry cleaning methods either require considerably more steps added to the overall dry cleaning process thereby requiring additional time and expense in carrying out the procedure or additional pieces of dry cleaning machinery which takes up space and also adds to the expense of the operation.
 It is an object of the present invention to provide a dry cleaning means and method for its operation for removing excess cleaning solvent from the fabrics cleaned during the dry cleaning process thereby rendering it more environmentally friendly. The removed solvent is recaptured and contained rather than emitted into the atmosphere.
 The dry cleaning method and apparatus of the present invention removes excess perchlorethylene (PERC) and other volatile cleaning solvents from clothing and fabric by injecting a predetermined amount of steam into a dry cleaning unit or vat wherein the solvent saturated clothing and fabric have been treated. The hot steam further volatilizes any additional PERC remaining in or on the fabric and this is removed from the container by vacuum. The PERC/steam mixture is then condensed and the two components separated for re-use.
FIG. 1 is an over-all schematic side view of a standard dry cleaning dryer with the attached PERC steam stripper of the present invention.
 During the course of the dry cleaning cycle in any standard dry cleaning system, the volatile cleaning solvents such as perchloroethylene (PERC) will often become absorbed into certain fabrics or clothing articles in excess amounts. Dense fabrics such as camel hair or wool often pose a problem in this regard. In many of the dry cleaning processes known in the art, the PERC cleaning solvent is not always fully removed and thus can result in an unpleasant odor or feel when the article of clothing is worn.
 The present apparatus and method insures that all of the cleaning solvent used in the dry cleaning process is removed from all the articles of clothing without damaging even the most sensitive of fabrics. This is achieved by injecting a pre-determined amount of steam into the drying vat or unit for a precisely defined period of time based upon the size of the load and the types of fabric being cleaned. The steam insures that any excess PERC remaining in the fabric being cleaned is removed by volatilizing the solvent molecules and then physically separating them from the fabric altogether. This not only results in a dry cleaned fabric material that is free from any undesirable chemical odor and slippery feel, but the perchloroethylene or other cleaning solvent can be separated, collected and condensed for re-use.
 Referring now to FIG. 1, a conventional dry-cleaning dryer (2) or vat is utilized to tumble dry the clothing articles and fabrics (not shown) that have been pre-treated with and are saturated with the cleaning solvent of choice, generally perchloroethylene (PERC). The volatile cleaning solvents for the most part are driven off the fabric through the application of heat at the pre-determined range and duration according to the types of fabric being cleaned.
 In the present invention as disclosed in FIG. 1, a steam source for the dryer is provided by the means of a steam pipe (4) located proximate to the dryer and is in communication therewith by means of a secondary conduct or pipe (6). A plurality of secondary conduits (not shown) could also feed off the same steam pipe (4) enabling several dry cleaning dryers to be utilized in tandem all at once. The steam itself is produced by a boiler either located on the premises or distally thereto and is fed via piping to the primary steam pipe (4).
 As discussed earlier, the amount of steam injected in the dryer and the amount of time during which this occurs depends on the size of the dry cleaning load and the types of fabric being cleaned. The temperature of the steam injected is generally governed by these factors and the type of solvent used. Obviously, the smaller or lighter the load and/or the more delicate the fabric, the shorter the duration of steam injection and stripping and/or the cooler the temperature.
 The duration of steam injection then is controlled by the use of a timer (8) located externally to the dry cleaning dryer or vat (2). Preferably, the timer is in juxtaposition to or attached to the outer casing or wall of the dryer (2) and can be manually set or adjusted therefrom. The timer (8) is in electrical communication (10) with the solenoid valve (12) which it operationally controls. Hence, when the timer is turned on to a specified duration of time, the solenoid valve (12) is turned to its open position and the hot steam from the steam pipe (4) is released and enters into tumble dryer (2). The steam enters into the dryer chamber (2) and over time fills the space not taken up by the fabric or clothes. As the clothes tumble about within the dryer (2), the hot steam thoroughly contacts the surface of the clothes and volatilizes or evaporates and cleaning solvent residue remaining thereon. Once the predetermined duration of solvent stripping has concluded, the timer (8) turns off thereby shutting the solenoid valve (12) and cutting off the flow of steam into the tumble dryer or vat (2).
 The dryer (2) is also provided with a conventional exhaust fan or vacuum (not shown) which collectively draws the steam and volatilized cleaning solvent out of internal chamber of the dryer (2) wherein it is subsequently cooled, condensed and collected. The two liquids can then be either physically separated or separated by distillation means as is known in the art. In this manner, the perchloroethylene (PERC) or other organic cleaning solvent as well as the water if necessary can be re-used thereby adding a cost saving benefit to the process. This is also ecologically sound in that the solvent is self contained and not hazardously discharged into the external environment.
 Referring again to FIG. 1, the solvent steam stripper apparatus of the present invention can alternatively be comprised of a manual shut off valve (14) for the shut off and/or open control of the steam release into the internal chamber of the dry cleaning dryer (2). This manual control valve can either be substituted for or utilized in conjunction with the electronically controlled solenoid valve (12) and timer (8) combination. If the manual shut off valve is used in the system by itself, it should only be used when the fabrics to be cleaned and steamed stripped are not delicate materials thereby requiring the use of precise steam injection periods and wherein these times can be operatively determined by the dry cleaner personnel themselves. When used on the secondary injection pipe (6) together or in tandem with the electronically controlled solenoid valve (12) and timer (8), the manual valve (14) can be utilized as an emergency shut off means or when appropriate, in lieu of the solenoid valve (12) and timer.
 As discussed earlier, the temperature of the steam injected into the dryer or vat (2) and the duration of time during which the steam contacts the clothes and strips the fabric of excess cleaning solvent is generally dependent upon the type of fabric being cleaned and, to a lesser degree, the type of solvent used. The more delicate the fabric, shorter steam stripping times and cooler steam temperatures provide the best cleaning results. Consequently, the more durable fabrics can generally withstand higher steam temperatures and longer steam stripping application times. And generally speaking, the duration of time during which the steam is allowed to contact the clothes is inversely related to the temperature of the steam. The hotter the steam, the shorter the steam/clothing contact period and vice versa.