Filter for vapor compression systems

Abstract

In a closed loop refrigerant system and method, a refrigerant liquid filter is provided downstream of the condenser to receive and clean high pressure, high temperature liquid refrigerant. The invention provides means for cooling liquid refrigerant so as to render otherwise soluble contaminants insoluble before leaving the filter. The means for cooling preferably includes a refrigerant line provided in thermal contact with the liquid refrigerant in the filter. The refrigerant line contains expanded refrigerant gas or expanded liquid/gas mixture, which is at a lower temperature than the liquid refrigerant received from the condenser. Condensed liquid refrigerant is provided to the filter, which filter further includes a filter element for removing contaminants that have been rendered insoluble by the cooling of the liquid refrigerant. The filtered liquid refrigerant, from which otherwise soluble contaminants and insoluble contaminants have been removed, can then be supplied to downstream components such as expansion devices, evaporators, and compressors.

1 . A refrigeration system comprising:
 a refrigerant loop comprising a high pressure side and a low pressure side, the high pressure side extending from an outlet of a compressor through a condenser to an expansion device, the low pressure side extending between the expansion device through an evaporator to an intake of the compressor;   a liquid refrigerant filter disposed in the high pressure side of the loop and communicably connecting the condenser and the flow-restricting expansion device, the filter comprising a filter element for removing solid and semi-solid contaminants; and   a liquid refrigerant cooling system to cool refrigerant received by the filter, the liquid refrigerant cooling system being configured and disposed to lower the temperature of the received refrigerant in the filter by an amount sufficient to render an otherwise soluble contaminant in the received refrigerant insoluble, and wherein the insoluble contaminant is captured by the filter element.   
   
   
       2 . The refrigeration system of  claim 1 , wherein the liquid refrigerant cooling system comprises a refrigerant line being configured to circulate expanded refrigerant sourced from the closed loop downstream of the expansion device. 
   
   
       3 . The refrigerant system of  claim 2 , wherein the filter comprises a housing defined by a sidewall, and wherein the refrigerant line is outside of the housing. 
   
   
       4 . The refrigerant system of  claim 3 , wherein the housing is substantially cylindrical, and the refrigerant line comprises a coil wrapped in a spiral configuration around the housing. 
   
   
       5 . The refrigerant system of  claim 1 , wherein the filter and the liquid refrigerant cooling system are contained within a common insulated housing. 
   
   
       6 . The refrigerant system of  claim 1 , wherein the filter comprises:
 a primary chamber communicably connected to the condenser, the primary chamber housing the filter element, the primary chamber defined by a first sidewall that separates the primary chamber from a secondary chamber, the first sidewall including an exit passageway for conveying liquid refrigerant to an expansion device located within the secondary chamber;   wherein the secondary chamber is defined by a second sidewall, the secondary chamber being configured to place expanded refrigerant from the expansion device in thermal contact with the first sidewall, the second sidewall further including a communicable connection to permit expanded refrigerant to flow to a downstream component of the refrigerant loop.   
   
   
       7 . The refrigerant system of  claim 6 , wherein the secondary chamber includes a baffle disposed to direct expanded refrigerant toward the first sidewall. 
   
   
       8 . The refrigerant system of  claim 7 , wherein the baffle is positioned adjacent an open end of the expansion device. 
   
   
       9 . The refrigerant system of  claim 8 , wherein the baffle is positioned between the open end of the expansion device and the communicable connection of the second sidewall, wherein refrigerant leaving the open end of the expansion device is redirected away from the communicable connection by the baffle to place the refrigerant in thermal contact with the first sidewall before exiting the secondary chamber via the communicable connection of the second sidewall. 
   
   
       10 . The refrigerant system of  claim 6 , wherein the filter further comprises an insulated outer housing surrounding the second sidewall. 
   
   
       11 . The refrigerant system of  claim 6 , wherein the first sidewall is substantially cylindrical. 
   
   
       12 . The refrigerant system of  claim 6 , wherein the secondary chamber includes a refrigerant line in thermal contact with the first sidewall. 
   
   
       13 . The refrigerant system of  claim 12 , wherein the first sidewall is substantially cylindrical. 
   
   
       14 . The refrigerant system of  claim 13 , wherein the refrigerant line is a coil wrapped in a spiral configuration around the first sidewall. 
   
   
       15 . The refrigerant system of  claim 12 , wherein the filter further comprises an insulated outer housing surrounding the second sidewall. 
   
   
       16 . A method of removing soluble contaminants from liquid refrigerant in the high pressure side of a closed loop refrigeration system, the method comprising the steps of:
 providing a liquid refrigerant filter in the high-pressure side of the closed loop, the filter communicably connecting the condenser and a flow-restricting expansion device, the filter comprising a filter element for removing solid and semi-solid contaminants;   receiving liquid refrigerant into the filter;   conveying liquid refrigerant from the filter to an expansion device;   circulating expanded refrigerant from the expansion device around a housing of the filter;   cooling liquid refrigerant in the filter by the circulation of refrigerant from the expansion device by an amount sufficient to render an otherwise soluble contaminant in the received liquid refrigerant insoluble; and   removing the contaminant using the filter element.   
   
   
       17 . The method of  claim 18 , further comprising the step of conveying the filtered liquid refrigerant to a downstream component in the closed loop refrigeration system. 
   
   
       18 . The method of  claim 19 , wherein the step of cooling refrigerant includes circulating refrigerant from the expansion device through a coil wrapped in a spiral configuration around the filter. 
   
   
       19 . A filter for a refrigerant system, the filter comprising:
 a primary chamber configured for communicable connection to the condenser of a refrigeration system to receive liquid from the condenser, the primary chamber housing a filter element, the primary chamber defined by a first sidewall that separates the primary chamber from a secondary chamber, the first sidewall including an exit passageway disposed and configured for conveying received liquid refrigerant to an expansion device located within the secondary chamber;   wherein the secondary chamber is defined by a second sidewall, the secondary chamber being configured to place expanded refrigerant from the expansion device in thermal contact with the first sidewall, the second sidewall further configured and disposed to permit connection to a downstream component of a refrigerant loop.   
   
   
       20 . The filter of  claim 19 , wherein the secondary chamber includes a refrigerant line in communication with the expansion device and in thermal contact with the first sidewall.