Device for regulating the pressure and/or temperature of the refrigerant fluid entering a compressor of a refrigeration apparatus, respective refrigeration apparatus and method for operating said regulation device

Abstract

Device for regulating (1) the pressure and/or temperature of the refrigerant fluid entering a compressor (101) of a refrigeration apparatus (100)) having a closed circuit (C) within which a flow rate (P) of refrigerant fluid whose pressure and/or temperature has to be regulated, circulates, a cooling device (102) and an evaporator (103), said regulation device (1) comprising at least one reciprocating compressor (2) equipped with at least one cylinder (7), at least one rod (8), at least one first piston (9a) integrally constrained to said rod and able to be translated within said cylinder, said cylinder (7) being equipped with a first chamber (10) comprising a first port (11) for the suction inflow of a first flow rate of said refrigerant fluid coming from said evaporator and a second port (12) for the outflow of said first flow rate of compressed refrigerant fluid contained in said first chamber (10) and intended to reach said compressor (101), said cylinder (7) further comprising a second chamber (20), which is fluidically separated from said first chamber by said first piston (9a) and equipped with at least one third port (21) for the inflow of a second flow rate (X2) of said refrigerant fluid to displace said piston and compress said refrigerant fluid contained in said first chamber (10), said regulation device (1) further comprising control means (50) for controlling the actuation of said at least one rod (8), which are adapted to divert said at least one second flow rate of said refrigerant fluid for controlling the displacement of said at least one first piston (9a) and compressing the refrigerant fluid of said first flow rate, which is contained in said first chamber, and to re-enter said second flow rate of refrigerant fluid into said closed circuit during the displacement of said at least one first piston (9a) during the step of suctioning said first flow rate of refrigerant fluid, characterised in that said control means (50) comprise a valve (51) equipped with an inlet line (51a) and an outlet line (51b) for said second flow rate, and at least one first passage (52a) through said valve, said valve being rotatable in such a way as to assume at least one first radial position (P1) in which the fluidic communication between said inlet line (51a) to said rotary valve (51) and said at least one second chamber (20) is allowed through said at least one first passage (52a), for the inflow of said second flow rate into said second chamber (20) and the compression of said first flow rate contained in said at least one first chamber (10), and at least one second radial position (P2) in which the fluidic communication between said at least one second chamber (20) and said outlet line (51b) of said rotary valve (51), for the suction of refrigerant fluid within said at least one first chamber (10), is allowed through said at least one passage (52a).

1 . Device for regulating ( 1 ) pressure and/or temperature of a refrigerant fluid entering a compressor ( 101 ) of a refrigeration apparatus ( 100 ) having a closed circuit (C) within which the refrigerant fluid having a flow rate (P), circulates,
 a cooling device ( 102 ) and an evaporator ( 103 ),   said regulation device ( 1 ) comprising at least one reciprocating compressor ( 2 ) equipped with at least one cylinder ( 7 ), at least one rod ( 8 ), at least one first piston ( 9   a ) integrally constrained to said rod and able to be translated within said cylinder, said cylinder ( 7 ) being equipped with a first chamber ( 10 ) comprising a first port ( 11 ) for the suction inflow of a first flow rate of said refrigerant fluid coming from said evaporator and a second port ( 12 ) for outflow of said first flow rate of compressed refrigerant fluid contained in said first chamber ( 10 ) and intended to reach said compressor ( 101 ),   each said cylinder ( 7 ) further comprising a second chamber ( 20 ) fluidically separated from said first chamber ( 10 ) by said first piston ( 9   a ) and including at least one third port ( 21 ) for inflow of a second flow rate (X2) of said refrigerant fluid to displace said first piston ( 9   a ) and compress said refrigerant fluid contained in said first chamber ( 10 ),   said regulation device ( 1 ) further comprising control means ( 50 ) for controlling actuation of said at least one rod ( 8 ), and adapted to divert said at least one second flow rate of said refrigerant fluid for controlling the displacement of said at least one first piston ( 9   a ) and compressing the refrigerant fluid of said first flow rate, which is contained in said first chamber ( 10 ), and to re-enter said second flow rate of refrigerant fluid into said closed circuit during the displacement of said at least one first piston ( 9   a ) during the step of suctioning said first flow rate of refrigerant fluid, wherein said control means ( 50 ) comprise a rotary valve ( 51 ) equipped with an inlet line ( 51   a ) and an outlet line ( 51   b ) for said second flow rate, and at least one first passage ( 52   a ) through said rotary valve, said rotary valve being rotatable to assume at least one first radial position (P1) in which fluidic communication between said inlet line ( 51   a ) to said rotary valve ( 51 ) and said at least one second chamber ( 20 ) is allowed through said at least one first passage ( 52   a ), for the inflow of said second flow rate into said second chamber ( 20 ) and the compression of said first flow rate contained in said at least one first chamber ( 10 ), and at least one second radial position (P2) in which the fluidic communication between said at least one second chamber ( 20 ) and said outlet line ( 51   b ) of said rotary valve ( 51 ), for the suction of refrigerant fluid within said at least one first chamber ( 10 ), is allowed through said at least one passage ( 52   a ).   
     
     
         2 . The device according to  claim 1 , wherein said reciprocating compressor ( 2 ) comprises at least one further piston ( 9   b ) integrally constrained to said at least one rod ( 8 ) and able to be translated within said cylinder ( 7 ), wherein said cylinder ( 7 ) is equipped with a further first chamber ( 10   a ) comprising a further first port ( 11   a ) for the inflow of said first flow rate of said refrigerant fluid coming from said evaporator and a further second port ( 12   a ) for the outlet of said first flow rate of compressed refrigerant fluid contained in said further first chamber ( 10   a ) and intended to reach said compressor ( 101 ), said cylinder ( 7 ) further comprising a further second chamber ( 20   a ) fluidically separated from said further first chamber ( 10   a ) by said further piston ( 9   b ) having at least one further third port ( 21   a ) for the inflow of a second flow rate of said refrigerant fluid to displace said further piston ( 9   b ) and compress said refrigerant fluid contained in said further first chamber ( 10 ), said rotary valve including at least one second passage ( 52   b ) such that, at least when said rotary valve assumes said first radial position (P1), the fluidic communication between said at least one further second chamber ( 20   a ) and said outlet line of said rotary valve, for the suction of refrigerant fluid within said at least one further first chamber ( 10   a ), is allowed through said at least one second passage ( 52   b ), and at least when said rotary valve assumes said second radial position (P2), the fluidic communication between said inlet line ( 51   a ) of said rotary valve and said at least one further second chamber ( 20   a ) for the inflow of said second flow rate into said further second chamber ( 20   a ) and the compression of said first flow rate contained in said at least one further first chamber ( 10   a ), is allowed through said at least one second passage ( 52   b ). 
     
     
         3 . The device according to  claim 1 , further comprising regulation means ( 53 ) for regulating a rotation speed of said rotary valve ( 51 ) and for varying a switching frequency between said first (P1) and said second (P2) radial positions. 
     
     
         4 . The device according to  claim 3 , wherein said regulation means ( 53 ) for said rotary valve ( 51 ) comprise an electric motor ( 55 ) mechanically combined with said rotary valve for its rotation, an inverter ( 56 ) adapted to regulate a rotation speed of said electric motor, and a control unit ( 57 ) functionally connected to said inverter to control its operation. 
     
     
         5 . The device according to  claim 3 , further comprising a pressure sensor ( 58 ) arranged along the inlet line ( 51   a ) to said rotary valve, said pressure sensor functionally connected to said control unit ( 57 ) such that the rotation speed of said valve is varied depending on the pressure measured by said pressure sensor. 
     
     
         6 . The device according to  claim 3 , further comprising a pressure sensor ( 59 ) and/or a temperature sensor ( 60 ) which are arranged along the inlet line ( 2   a ) of said reciprocating compressor ( 2 ), said pressure sensor and/or said temperature sensor being functionally connected to said control unit ( 57 ) such that the rotation speed of said rotary valve is varied depending on the pressure and/or temperature measured by said pressure sensor and/or by said temperature sensor. 
     
     
         7 . The device according to  claim 1 , further comprising at least one position sensor ( 61 ) for determining the position along said at least one cylinder of said first piston and/or said further piston of said reciprocating compressor to determine the position reached by said first piston and/or said further piston, said position sensor being functionally connected to said regulation means such that the rotation speed of said valve is varied depending on the information obtained from said at least one position sensor. 
     
     
         8 . The device according to  claim 7 , wherein said position sensor ( 61 ) comprises at least one proximity sensor. 
     
     
         9 . A refrigeration apparatus ( 100 , 100 ′) comprising a closed circuit (C) within which a flow rate (P) of a refrigerant fluid circulates, a compressor ( 101 ), a cooling device ( 102 ), an evaporator ( 103 ) from which a first flow rate flows out, at least one expansion valve ( 104 ), and at least one regulation device according to  claim 1 ,
 wherein said closed circuit further comprises at least one economizer branch ( 105 ) along which a second flow rate of refrigerant fluid flows, said at least one economizer branch fluidically connecting a length of said closed circuit comprised between said cooling device and said expansion valve and a length comprised between said evaporator ( 103 ) and said compressor ( 101 ), and 
 wherein said reciprocating compressor of said regulation device ( 1 ) has said first flow rate exiting said evaporator at the inlet, said rotary valve has said second flow rate circulating along said economizer branch ( 105 ) at the inlet, and said outlet line of said rotary valve is connected to the inlet line of said compressor ( 101 ), downstream of said reciprocating compressor ( 2 ). 
 
     
     
         10 . A refrigeration apparatus ( 100 ″) comprising a closed circuit (C) within which a flow rate (P) of a refrigerant fluid circulates, a compressor ( 101 ), a cooling device ( 102 ), an evaporator ( 103 ), and a regulation device according to  claim 1 , said reciprocating compressor ( 2 ) of said regulation device having said first flow rate exiting from the evaporator at the inlet and said rotary valve having the flow rate exiting said refrigeration device ( 102 ) at the inlet, the outlet line of said rotary valve being connected to said evaporator. 
     
     
         11 . The refrigeration apparatus ( 200 ) according to  claim 10 , wherein said flow rate of refrigerant fluid circulating within said closed circuit is identical to said first flow rate of refrigerant fluid and said second flow rate of refrigerant fluid. 
     
     
         12 . A method for operating the regulation device ( 1 ) according to  claim 1 , said method comprising the steps of:
 a) allowing the inflow of a first flow rate of refrigerant fluid within said at least one first chamber ( 10 ) of said cylinder ( 7 ) of said reciprocating compressor ( 2 );   b) allowing the inflow of a second flow rate of refrigerant fluid within said at least one second chamber ( 20 ) of said cylinder of said reciprocating compressor ( 2 ) to control the displacement of said at least one first piston ( 9   a ) and compress the refrigerant fluid of said first flow rate, which is contained in said first chamber ( 10 );   c) re-entering said second flow rate of refrigerant fluid into said closed circuit during the displacement of said at least one first piston ( 9   a ) while suctioning said first flow rate of refrigerant fluid during said step a);   wherein said step c) comprises a step c1) of rotating said rotary valve ( 51 ) in said first position to assume at least one first radial position (P1) in which fluidic communication between said inlet line ( 51   a ) to said rotary valve ( 51 ) and said at least one second chamber ( 20 ) is allowed through said at least one first passage ( 52   a ), for the inflow of said second flow rate (X2) into said second chamber ( 20 ) and the compression of said first flow rate contained in said at least one first chamber ( 10 ), and a step c2) of rotating said rotary valve in a second radial position (P2) in which fluidic communication between said at least one second chamber ( 20 ) and said outlet line ( 51   b ) of said rotary valve ( 51 ) is allowed through said at least one passage ( 52   a ), for the suction of refrigerant fluid within said at least one first chamber ( 10 ).   
     
     
         13 . The method according to  claim 12 , further comprising step d): regulating a switching speed of said rotary valve ( 51 ) from said first radial position to said second radial position for operation of the regulation device ( 1 ) depending on the pressure of the refrigerant fluid entering said rotary valve, either depending on the pressure and/or temperature of the refrigerant fluid entering said first chamber of said reciprocating compressor or depending on the position reached by said at least one first piston within said cylinder ( 7 ) of said reciprocating compressor ( 2 ).