Liquified gas dry-cleaning system with pressure vessel temperature compensating compressor

#The present invention relates to liquified gas dry-cleaning systems and, more particularly, to a liquified gas dry-cleaning system having means for minimizing temperature decreases within the pressure vessel cleaning chamber incident to evacuation of gases released during a dry-cleaning cycle.

#Known dry-cleaning processes consist of a wash, rinse, and drying/draining cycle with solvent recovery. During this process, items, such as garments, are loaded into a basket positioned within a vessel and immersed in a dry-cleaning solvent pumped into the vessel from a base tank. Conventional dry-cleaning solvents include perchloroethylene (PCE), petroleum-based or Stoddard solvents, CFC-113, and 1,1,1-trichloroethane, all of which are generally aided by a detergent. The use of these solvents, however, poses a number of health and safety risks as well as being environmentally hazardous.

#To minimize these problems, dry-cleaning systems that use liquified gas as a cleaning medium, such as liquid carbon dioxide, have been developed. An example of such a cleaning system is found in U.S. Pat. No. 5,339,844 entitled “Low Cost Equipment For Cleaning Using Liquifiable Gas.” This system includes a source of liquified gas, an enclosed pressure vessel that forms a cleaning chamber for containing items to be cleaned and a bath of the liquified gas, and a circulatory system for circulating the liquified gas between the source and the vessel. Additionally, as is typical of the prior art, the system utilizes a compressor in the circulatory system, positioned remotely from the pressure vessel, which is used to evacuate gaseous vapors in the vessel released during a cleaning cycle.

#Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

#FIG. 1 is a schematic of a dry-cleaning system in accordance with the invention; and

#FIG. 2 is an enlarged fragmentary section of the compressor used in the dry-cleaning system illustrated in FIG. 1.

#While the invention is susceptible of various modifications and alternative constructions, a certain illustrated embodiment thereof has been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention.

#Referring now more particularly to FIG. 1, there is shown an illustrative dry-cleaning machine 10 embodying the present invention. The dry-cleaning machine 10 preferably utilizes liquified carbon dioxide as the dry-cleaning solvent, typical of U.S. Pat. Nos. 5,651,276, 5,467,492, and 5,651,276 the disclosures of which are incorporated herein by reference. Nevertheless, it will be appreciated that the invention described hereinafter may also be used in connection with other types of liquified gas dry-cleaning processes. Accordingly, the description that follows is not intended to be limiting.

#In general, the dry-cleaning machine 10 includes a pressurize vessel 11 which defines a cleaning chamber 13 having a rotatable basket 12 supported therein for containing items to be cleaned, for example, garments. Liquified carbon dioxide used as the dry-cleaning solvent is directed into the vessel 11 from a pressurized storage tank 14 through inlet 15. As is known in the art, the vessel 11 may be further equipped with a pressure check valve, pressure sensor, and temperature sensor to aid in temperature and pressure control for maintaining the carbon dioxide in liquid phase during cleaning. Additionally, the dry-cleaning machine 10 includes a pressurizable purge tank 26, a cyclone separator 27, and a solvent recovery device 30 all of conventional design.