Method and apparatus for common pressure and oil equalization in multi-compressor systems

Abstract

A compressor system includes a first compressor and a second compressor. A common equalization line fluidly couples the first compressor and the second compressor and provides a single path for passage of fluids between the first compressor and the second compressor. An obstruction device is disposed in the common equalization line. Responsive to one of the first compressor and the second compressor being deactivated while the other of the first compressor and the second compressor remains active, the obstruction device is in a closed configuration. When in the closed configuration, the obstruction device prevents flow of fluid between the first compressor and the second compressor. Prevention of fluid flow between the first compressor and the second compressor causes at least minimum prescribed fluid levels to be maintained in the first compressor and the second compressor.

What is claimed is: 
     
         1 . A compressor system comprising:
 a first compressor and a second compressor;   a common equalization line fluidly coupling the first compressor and the second compressor, the common equalization line providing a single path for passage of fluids between the first compressor and the second compressor;   an obstruction device disposed in the common equalization line;   wherein, responsive to one of the first compressor and the second compressor being deactivated while the other of the first compressor and the second compressor remains active, the obstruction device is in a closed configuration thereby preventing flow of fluid between the first compressor and the second compressor; and   wherein prevention of fluid flow between the first compressor and the second compressor causes at least minimum prescribed fluid levels to be maintained in the first compressor and the second compressor.   
     
     
         2 . The compressor system of  claim 1 , wherein the first compressor and the second compressor are of approximately equal capacity. 
     
     
         3 . The compressor system of  claim 1 , wherein the obstruction device is a solenoid valve. 
     
     
         4 . The compressor system of  claim 3 , wherein the solenoid valve is biased in an open position. 
     
     
         5 . The compressor system of  claim 1 , wherein the obstruction device is in the closed configuration prior to deactivating one of the first compressor and the second compressor. 
     
     
         6 . The compressor system of  claim 5 , wherein the obstruction device prevents fluid starvation in at least one of the first compressor and the second compressor. 
     
     
         7 . The compressor system of  claim 6 , wherein the obstruction device facilitates lower partial-load power consumption by the compressor system. 
     
     
         8 . The compressor system of  claim 1 , wherein approximately 0% to approximately 50% of a cross-sectional area of the common equalization line contains liquid. 
     
     
         9 . The compressor system of  claim 8 , wherein approximately 05 to approximately 50% of the cross-sectional area of the common equalization line contains gaseous refrigerant. 
     
     
         10 . A method of maintaining minimum prescribed fluid levels in a multiple compressor system, the method comprising:
 utilizing the multiple compressor system in at least one of full-load operation such that all compressors of the multiple compressor system are operational, partial-load operation such that at least one compressor of the multiple compressor system is de-activated, and an idle state such that all compressors of the multiple compressor system are deactivated;   responsive to the multiple compressor system being in partial-load operation, closing an obstruction device disposed between an active compressor and the at least one de-activated compressor of the multiple compressor system;   preventing, via the obstruction device, fluid flow from the at least one compressor that is de-activated into at least one compressor of the multiple compressor system that is active; and   maintaining at least prescribed fluid levels in the compressors of the multiple compressor system during partial-load operation.   
     
     
         11 . The method of  claim 10 , comprising:
 transitioning the multiple compressor system from the idle state to partial-load operation; and   placing the obstruction device in a closed configuration prior to the transitioning.   
     
     
         12 . The method of  claim 10 , comprising transitioning the compressor system from the idle state to full-load operation; and
 retaining the obstruction device in an open configuration during the transition.   
     
     
         13 . The method of  claim 10 , comprising transitioning the multiple compressor system from partial-load operation to full-load operation such that all compressors of the multiple compressor system are operational; and
 placing the obstruction device in an open configuration after the transition.   
     
     
         14 . The method of  claim 10 , comprising transitioning the multiple compressor system from full-load operation such that all compressors of the multiple compressor system are operational to partial-load operation where at least one compressor of the multiple compressor system is deactivated; and
 placing the obstruction device in a closed configuration prior to the transition.   
     
     
         15 . The method of  claim 10 , comprising transitioning the multiple compressor system from full-load operation such that all compressors of the multiple compressor system are operational to idle such that no compressors of the multiple compressor system are active; and
 retaining the obstruction device in an open configuration during the transition.   
     
     
         16 . The method of  claim 10  wherein the obstruction device is a solenoid valve. 
     
     
         17 . A compressor system comprising:
 a first compressor and a second compressor;   a common equalization line fluidly coupling the first compressor and the second compressor, the common equalization line providing a single path for passage of fluids between the first compressor and the second compressor;   a solenoid valve disposed in the common equalization line;   wherein, responsive to one of the first compressor and the second compressor being deactivated while the other of the first compressor and the second compressor remains active, the solenoid valve is closed prior to deactivation of the at least one of the first compressor and the second compressor thereby preventing flow of fluid between the first compressor and the second compressor; and   wherein prevention of fluid flow between the first compressor and the second compressor causes at least minimum fluid levels to be maintained in the first compressor and the second compressor.   
     
     
         18 . The compressor system of  claim 17 , wherein the first compressor and the second compressor are of approximately equal capacity. 
     
     
         19 . The compressor system of  claim 17 , wherein approximately 0% to approximately 50% of a cross-sectional area of the common equalization line contains liquid. 
     
     
         20 . The compressor system of  claim 19 , wherein the solenoid valve prevents fluid starvation in at least one of the first compressor and the second compressor.