Reciprocating compressor with high freezing effect

Abstract

A reciprocating compressor ( 1 ) for a coolant comprising at least one drive shaft ( 3 ) actuated by a motor ( 2 ); one compression piston ( 9 ) for the coolant (R) slidable in a respective compression chamber ( 5 ) and actuated by said shaft ( 3 ); suction system ( 13 ) to supply the coolant (R) to be compressed in said compression chamber ( 5 ) at a suction pressure (P 1 ); a delivery system ( 15 ) to inject the compressed coolant (R) in an external refrigerating circuit or machine. The compressor presents a distribution system ( 19, 21 ) to inject in the compression chamber, in phase with the movement of the piston, coolant at a pressure intermediate between the suction pressure and the delivery pressure.

1 . A reciprocating compressor for a coolant, comprising:
 at least one piston slidable in a compression chamber and actuated by a drive shaft, wherein at least one supply port exits in said at least one compression chamber a supply port for supplying a coolant at a distribution pressure intermediate between a delivery pressure and a suction pressure of the compressor, and to said at least one supply port a distribution system is associated, said distribution system comprising a distributor slidable in a distribution chamber in synchronous manner with said at least one piston, said distributor controlling opening and closing of said supply port in said compression chamber, said distributor being actuated by said at least one drive shaft through a connecting rod-crank mechanism.   
     
     
         2 . A compressor as claimed in  claim 1 , wherein said distributor presents at least one passage duct to put in fluid connection said distribution chamber with said at compression chamber through said supply port. 
     
     
         3 )- 4 ). (canceled) 
     
     
         5 . A reciprocating compressor as claimed in  claim 1 , further comprising an inlet system to supply the coolant in said distribution chamber at the distribution pressure intermediate between the suction pressure and the delivery pressure of the compressor. 
     
     
         6 . A reciprocating compressor as claimed  claim 1 , wherein said distributor is designed to open and to close gradually an entrance end of said at least one supply port, an exit end of said supply port being opened and closed by said at least one piston. 
     
     
         7 . A reciprocating compressor as claimed in  claim 1 , wherein said distributor performs a shorter stroke relative to that of said at least one piston. 
     
     
         8 . A reciprocating compressor as claimed in  claim 2 , wherein said at least one passage duct presents at least one entrance aperture on a head of the distributor and at least one exit aperture arranged in an intermediate position on a lateral shell of said distributor. 
     
     
         9 . A reciprocating compressor as claimed in  claim 8 , wherein said at least one exit aperture exits in a compartment obtained on said lateral shell of the distributor, in said compartment being inserted and slidable a shaped seal sliding block, which presents a through channel close said at least one exit aperture, said seal sliding block being designed to be pushed by the pressure of the coolant against a wall of said distribution chamber. 
     
     
         10 . A reciprocating compressor as claimed in  claim 9 , wherein said distributor comprises at least a first seal between the distribution chamber and the seal line block and at least one second seal between said seal sliding block and one compartment of a casing of the compressor. 
     
     
         11 . A reciprocating compressor as claimed in  claim 1 , wherein said at distributor and said at least one piston are mutually phased so as to open said at least one supply port when said at least one piston is about at a bottom dead center and/or said at least one piston is in compression phase. 
     
     
         12 . A reciprocating compressor as claimed in  claim 1 , further comprising another piston to provide at least two compression pistons slidable in respective compression chambers, each of said compression chambers presenting at least one supply port for a fluid connection with said distribution system. 
     
     
         13 . A reciprocating compressor as claimed in  claim 2 , wherein said at least one passage duct of the distributor is shaped so as to supply fluid in said at least two compression chambers in different positions of the drive shaft. 
     
     
         14 . A reciprocating compressor as claimed in  claim 1 , further comprising another piston to provide at least one pair of compression pistons displaced from each other by a phase angle and said distributor is displaced relative to said at least one pair of said compression pistons by respective intermediate angles equal to about half of said phase angle. 
     
     
         15 . A reciprocating compressor as claimed in  claim 8 , wherein said at least one piston presents at least one first seal close to the head, and at least one seal close to an end opposite to the head. 
     
     
         16 . A refrigerating plant comprising:
 a main circuit for a coolant, with a condenser, an expansion member, an evaporator, and a compressor comprising at least one piston slidable in a compression chamber and actuated by a drive shaft, wherein in said at least one compression chamber a supply port exits for supplying a coolant at a distribution pressure intermediate between a delivery pressure and a suction pressure of the compressor, and to said at least one supply port a distribution system is associated, said distribution system comprising a distributor slidable in a distribution chamber in synchronous manner with said at least one piston, said distributor controlling opening and closing of said supply port in said compression chamber, said at least one distributor being actuated by said at least one drive shaft through a connecting rod-crank mechanism;   an auxiliary circuit with an entrance of coolant cooled and/or condensed at high pressure, and an exit connected to said compressor, between said entrance and said exit being arranged an expansion member and an exchanger economizer, through which the coolant circulating in the auxiliary circuit cools a flow of the coolant circulating in the main circuit, the fluid at the exit of the auxiliary circuit presenting a pressure intermediate between the suction pressure and the delivery pressure of the compressor and being inserted, through said distribution system in said at least one compression chamber of the compressor.   
     
     
         17 . A refrigerating plant comprising:
 a main circuit for a coolant, with a condenser, an expansion member, an evaporator, and a compressor comprising at least one piston slidable in a compression chamber and actuated by a drive shaft, wherein in said at least one compression chamber a supply port exits for supplying a coolant at a distribution pressure intermediate between a delivery pressure and a suction pressure of the compressor, and to said at least one supply port a distribution system is associated, said distribution system comprising a distributor slidable in a distribution chamber in synchronous manner with said at least one piston, said distributor controlling opening and closing of said supply port in said compression chamber, said at least one distributor being actuated by said at least one drive shaft through a connecting rod-crank mechanism;   an auxiliary circuit with an entrance of undercooled coolant, and an exit connected to said compressor, between said entrance and said exit being arranged an expansion member and an exchanger economizer, through which the coolant circulating in the auxiliary circuit cools a flow of the coolant circulating in the main circuit; the fluid at the exit of the auxiliary circuit presenting the distribution pressure intermediate between the suction pressure and the delivery pressure of the compressor and being inserted, through said distribution system in said at least one compression chamber of the compressor.