Reciprocating Compressor Vented Piston

Abstract

A compressor ( 20 ) comprises: a case ( 22 ); and at least one piston ( 40 ) mounted for reciprocating movement, each in a respective cylinder ( 42 ) of the case. The at least one piston having a peripheral surface ( 50 ) and an upper surface ( 52 ), the upper surface having an outer portion ( 54 ) and a projection ( 80 ) extending from the upper surface. The at least one piston has a channel ( 220 ) positioned to pass flow from an area above the outer portion.

1 . A compressor ( 20 ) comprising:
 a case ( 22 ); and   at least one piston ( 40 ) mounted for reciprocating movement, each in a respective cylinder ( 42 ) of the case, the at least one piston having a peripheral surface ( 50 ) and an upper surface ( 52 ), the upper surface having an outer portion ( 54 ) and projection ( 80 ) extending from the upper surface,   
       wherein the at least one piston has:
 a closed channel ( 220 ) positioned to pass flow from an area above the outer portion. 
 
     
     
         2 . (canceled) 
     
     
         3 . The compressor of  claim 1  wherein:
 the projection has an upper end and a central recess ( 200 ) in the upper end; and 
 the channel has an upper end ( 226 ) at the recess. 
 
     
     
         4 . The compressor of  claim 1  wherein:
 the channel has a lower end ( 224 ) along a side of the projection. 
 
     
     
         5 . The compressor of  claim 1  wherein:
 the channel is one of a plurality of like channels distributed circumferentially about the at least one piston. 
 
     
     
         6 . The compressor of  claim 1  further comprising:
 a motor ( 28 ); 
 a crankshaft ( 34 ) driven by the motor; and 
 at least one connecting rod ( 48 ) coupling the crankshaft to the at least one piston. 
 
     
     
         7 . The compressor of  claim 1  wherein:
 the projection has a frustoconical lateral surface ( 82 ). 
 
     
     
         8 . The compressor of  claim 1  wherein:
 the channel comprises a drilled hole. 
 
     
     
         9 . The compressor of  claim 1  wherein:
 the at least one piston comprises a plurality of identical pistons. 
 
     
     
         10 . The compressor of  claim 1  wherein:
 the cylinder is formed in a cylinder block ( 44 ); 
 a valve plate assembly ( 70 ) is mounted to the cylinder block; and 
 the at least one piston has a top-dead-center condition wherein the projection is at least partially within the valve plate assembly. 
 
     
     
         11 . The compressor of  claim 10  wherein:
 the valve plate assembly has a seat ( 132 ) forming a seating surface ( 130 ) of a suction valve; and 
 in the top-dead-center condition, the projection is partially received within the seat. 
 
     
     
         12 . The compressor of  claim 10  wherein:
 the seat forms an outer seating surface ( 160 ) of a discharge valve; 
 the valve plate assembly has an inner seat ( 166 ) forming an inner seating surface ( 164 ) of the discharge valve; 
 the at least one piston has a recess ( 200 ) in the projection; and 
 in the top-dead-center condition, the inner seat is partially received within the recess. 
 
     
     
         13 . A method for manufacturing the compressor of  claim 1 , the method comprising:
 drilling to form the channel.   
     
     
         14 . A method for using the compressor of  claim 1 , the method comprising:
 reciprocating the at least one piston in the respective cylinder, during an upward portion of the reciprocating a flow of fluid moving upward in the channel.   
     
     
         15 . The method of  claim 14  wherein:
 the flow of fluid is from a region adjacent a suction valve toward a discharge valve. 
 
     
     
         16 . A vapor compression system comprising the compressor of  claim 1 . 
     
     
         17 . The vapor compression system of  claim 16  being a refrigeration system.