System and method for washing articles employing a densified cleaning solution, and use of a fluid displacement device therein

Abstract

A dry cleaning system arranged for washing articles employing a cleaning solution. The dry cleaning system includes awash tank ( 2 ) for washing an article to be washed with a cleaning solution. The wash tank ( 2 ) is arranged for washing the article at an increased pressure compared to atmospheric pressure. The dry cleaning system includes a fluid displacement device ( 1 ), such as a pump, connected to the wash tank ( 2 ) and is arranged for transferring the cleaning solution through the dry cleaning system in a first operational mode. The fluid displacement device is arranged to reduce the pressure in the wash tank towards atmospheric pressure in a second operational mode.

What is claimed is: 
     
         1 . method for washing an article in a dry cleaning system employing a cleaning solution, said cleaning solution comprising a liquid and a vapor, said method comprising:
 washing in a wash tank an article to be washed with said cleaning solution at hyperatmospheric pressure;   storing said cleaning solution in a central storage tank, wherein said central storage tank is closeably connected to said wash tank;   transferring said cleaning solution by a single fluid displacement device being a pumping and compressing unit connected through a wash tank-pump line to said wash tank for transfer of cleaning solution from the wash tank to the fluid displacement device and through a further line ( 108 ) for transfer of liquid from the fluid displacement device to the wash tank; the wash-tank line and the further line each closeable by a respective valve ( 26 ;  28 );   wherein the method comprises the steps of:   operating said fluid displacement device for transferring of said cleaning solution in liquid form in said dry cleaning system;   operating said same fluid displacement device for depressurizing said wash tank, after removal of the liquid cleaning solution from the wash tank to the central storage tank, by removing the vapor from the wash tank by means of compressing the removed vapor,   wherein the fluid displacement device is a positive-displacement device, being a reciprocating pump/compressor device or a piston device to pressurize fluid, arranged for transferring liquid and vapor fluid, and for compressing vapor fluid.   
     
     
         2 . The method according to  claim 1 , wherein the step of operating said same fluid displacement device for depressurizing said wash tank comprises the step of reducing the pressure in said wash tank towards atmospheric pressure. 
     
     
         3 . The method according to  claim 2 , wherein the step of operating said same fluid displacement device for
 depressurizing said wash tank comprises the step of removing vapor from said wash tank.   
     
     
         4 . The method according to  claim 3 , wherein the step of operating said same fluid displacement device for depressurizing said wash tank comprises the step of compressing said vapor removed from said wash tank. 
     
     
         5 . The method according to  claim 1 , wherein the method comprises the steps of:
 operating said fluid displacement device for pumping said cleaning solution in liquid form; and   operating the fluid displacement device for compressing said cleaning solution in vapor form.   
     
     
         6 . A method for washing articles in a dry cleaning system employing a cleaning solution, comprising washing said washing articles in a wash tank at a hyperatmospheric pressure, wherein said dry cleaning system comprises a fluid displacement device according to  claim 1  for depressurizing said wash tank towards atmospheric pressure. 
     
     
         7 . A method for washing articles in a dry cleaning system employing a cleaning solution, comprising displacing and compressing fluids from said dry cleaning system with washing articles employing a cleaning solution in accordance with a fluid displacement device according to  claim 1 . 
     
     
         8 . The method according to  claim 1 , wherein the fluid displacement device compresses cleaning solution in vapor form.