Compressor

Abstract

A compressor has a crankshaft, at least one cylinder, and at least one piston. Each such piston is positioned for reciprocal motion at least partially within associated such cylinder and coupled to the crankshaft so as to drive the reciprocal motion. The compressor includes an inlet, a suction plenum, an outlet, a sump, and a valve between the sump and suction plenum. The valve may provide a desired discharge of refrigerant from a sump oil accumulation while controlling sump pressure and loss of the oil.

1 . A compressor comprising: 
 a crankshaft;    at least one cylinder;    at least one piston, each such piston positioned for reciprocal motion at least partially within an associated cylinder and coupled to the crankshaft so as to drive said reciprocal motion;    an inlet;    a suction plenum;    an outlet;    a sump; and    a valve between the sump and suction plenum.    
   
   
       2 . The compressor of  claim 1  wherein: 
 the valve is pressure-actuated.    
   
   
       3 . The compressor of  claim 2  wherein: 
 the valve has a first threshold relief pressure and a second threshold reset pressure of like sign.    
   
   
       4 . The compressor of  claim 1  wherein: 
 there are first and second such cylinders.    
   
   
       5 . The compressor of  claim 1  further comprising: 
 an oil pump drawing oil from an accumulation in the sump.    
   
   
       6 . The compressor of  claim 1  in combination with: 
 a refrigerant flow from the inlet to the outlet.    
   
   
       7 . The compressor of  claim 1  wherein the refrigerant is selected from the group consisting of: 
 HCFCs; and    HFCs.    
   
   
       8 . A compressor comprising: 
 a crankshaft;    at least one cylinder;    at least one piston, each such piston positioned for reciprocal motion at least partially within an associated such cylinder and coupled to the crankshaft so as to drive said reciprocal motion;    an inlet;    a suction plenum;    an outlet;    a sump; and    means, including a valve, for limiting sump-to-suction plenum lubricant loss while limiting a bearing load.    
   
   
       9 . The compressor of  claim 8  wherein the valve is a single pressure-actuated mechanical valve.  
   
   
       10 . A method for operating a reciprocating-type compressor comprising: 
 starting the compressor;    permitting an overpressure of a sump pressure in excess of a suction plenum pressure to reach substantially a first threshold amount; and    opening a valve to at least partially relieve the overpressure.    
   
   
       11 . The method of  claim 10  further comprising: 
 reclosing the valve when the overpressure is relieved to substantially a second threshold amount.    
   
   
       12 . The method of  claim 11  wherein: 
 said opening and said reclosing are mechanically pressure-actuated.    
   
   
       13 . The method of  claim 11  wherein: 
 said opening and said reclosing are repeated for a plurality of cycles.    
   
   
       14 . The method of  claim 11  wherein: 
 the first threshold amount is 50-150 psi; and    the second threshold amount is 50-70 psi less than the first threshold amount.    
   
   
       15 . With a reciprocating compressor or compressor configuration, a method of remanufacturing or reengineering comprising: 
 replacing an open aperture between a sump and a suction plenum with a valve.    
   
   
       16 . The method of  claim 15  wherein the replacing comprises: 
 positioning said valve at said aperture.    
   
   
       17 . The method of  claim 15  wherein the valve is a pressure-actuated valve.  
   
   
       18 . The method of  claim 15  further comprising: 
 selecting the valve so as to provide a desired discharge of refrigerant from a sump oil accumulation while controlling sump pressure and loss of oil from said accumulation.    
   
   
       19 . The method of  claim 18  wherein: 
 the discharge of refrigerant from the sump oil accumulation is faster and/or the sump pressure is controlled to a lower peak and/or less of said oil is lost in the remanufactured or reengineered compressor or compressor configuration relative to a baseline compressor or compressor configuration.    
   
   
       20 . The method of  claim 18  wherein the selecting comprises: 
 testing with a plurality of such valves having different pressure responsive characteristics; or    varying a pressure response characteristic of a single such valve or a test valve.