Method for Controlling Delivery Quantity, and Reciprocating Compressor Having Delivery Quantity Control

Abstract

The invention relates to a method for delivery quantity control of a reciprocating compressor, wherein the motion of a closing organ ( 5 b ) of an automatic suction valve ( 5 ) is influenced during at least one part of a cycle of the crankshaft by means of a refraction gripper ( 6 ), wherein the method comprises a continuously variable return flow control, wherein the retraction gripper ( 6 ) contacts the closing organ ( 5 b) and prevents the same from closing during a first partial segment (K 1 ) of the cycle of the crankshaft, and wherein the retraction gripper ( 6 ) is retracted during a second partial segment (K 2 ) of the cycle of the crankshaft and the closing organ ( 5 b ) is closed, wherein the retraction gripper ( 6 ) is retracted such that the speed of the moving closing organ ( 5 b ) is reduced prior to contacting the suction valve ( 5 ).

1 . Method for delivery quantity control of a reciprocating compressor, in which the movement of a closing body ( 5   b ) of a self-acting intake valve ( 5 ) is influenced during at least part of a cycle of crank rotation by an unloader ( 6 ) driven by a control device ( 2 ), wherein the method comprises a continuously variable backflow regulation, in which the unloader ( 6 ) lies against the closing body ( 5   b ) during a first section (K 1 ) of the cycle of crank rotation and prevents its closure, and in which the unloader ( 6 ) is driven back during a second section (K 2 ) of the cycle of crank rotation and the closing body ( 5   b ) is closed, wherein the unloader ( 6 ) is driven back in such a way that the speed of the moving closing body ( 5   b ) is reduced prior to its seating on the intake valve ( 5 ). 
     
     
         2 . Method for delivery quantity regulation according to  claim 1 , characterised in that the method comprises a skip regulation, in which the unloader ( 6 ) prevents closure of the closing body ( 5   b ) during a whole cycle of crank rotation, wherein the delivery quantity is regulated by at least a combination of continuously variable backflow regulation and skip regulation. 
     
     
         3 . Method according to  claim 1 , characterised in that, during seating on the intake valve ( 5 ), the speed of the closing body ( 5   b ) falls below a permitted impingement speed, and that this is less than 0.1 m/s. 
     
     
         4 . Method according to  claim 1 , characterised in that, after the seating of the closing body ( 5   b ), the control device ( 2 ) moves the unloader ( 6 ) still further and then brings it to rest, in order to distance the unloader ( 6 ) from the closing body ( 5   b ) and to bring the unloader ( 6 ) to an end position. 
     
     
         5 . Method according to  claim 1 , characterised in that, after the seating of the closing body ( 5   b ), during a third section (k 3 ) of the crank rotation, the control device ( 2 ) once again accelerates the unloader ( 6 ) and then brings it to rest, in order to distance the unloader ( 6 ) from the closing body ( 5   b ) and to bring the unloader ( 6 ) to an end position. 
     
     
         6 . Method according to  claim 1 , characterised in that, the control device ( 2 ) comprises an adaptive pre-control with which the stroke (A) and the speed (C) of the unloader ( 6 ) are regulated. 
     
     
         7 . Method according to  claim 1 , characterised in that, the intake valve ( 5 ) is influenced by the control device ( 2 ) and the unloader ( 6 ) in such a way that a closing body ( 8   b ) of a pressure valve ( 8 ) of the reciprocating compressor is opened during at least a predetermined total opening angle (K v ) of a crank rotation. 
     
     
         8 . Method according to  claim 7 , characterised in that, the predetermined total opening angle (K v ) is at least 10°, and preferably lies at least in the range between 20° and 30°. 
     
     
         9 . Method according to  claim 1 , characterised in that, the intake valve ( 5 ) is influenced by the control device ( 2 ) and the unloader ( 6 ) in such a way that a closing body ( 8   b ) of a pressure valve ( 8 ) of the reciprocating compressor is opened at least during a predetermined angular range (Δ) of a crank rotation before the upper, respectively lower dead centre (O TP , U TP ). 
     
     
         10 . Method according to  claim 9 , characterised in that, the predetermined angular range (Δ) is at least 10°, and preferably lies at least in the range between 20° and 30°. 
     
     
         11 . Method according to  claim 1 , characterised in that, various delivery quantities are regulated in such a way, that, for large delivery streams, the intake valve ( 5 ) is automatically driven during certain cycles and is driven with constantly variable backflow regulation during certain cycles; that, that, for middle-sized delivery quantities, the intake valve ( 5 ) is driven during every cycle with constantly variable backflow regulation; and that, for small delivery quantities, the intake valve ( 5 ) is constantly held open during certain cycles under skip regulation, and driven with constantly variable backflow regulation during certain cycles. 
     
     
         12 . Reciprocating compressor with delivery quantity regulation, in particular with constantly variable delivery quantity regulation, with an unloader ( 6 ) arranged on at least one self-acting intake valve ( 5 ) of the compressor, with a control device ( 2 ) for driving the unloader ( 6 ), as well as with a closing body ( 5   b ) of the intake valve ( 5 ), wherein the unloader ( 6 ) acts on the closing body ( 5   b ) in such a way that the intake valve ( 5 ) is opened over a controllable part of the working stroke of the compressor, characterised in that, the control device ( 2 ) comprises a drive mechanism ( 2   n ) which acts via a connection means ( 7 ) on the unloader ( 6 ), wherein the control device ( 2 ) comprises a constantly variable backflow regulation, in which the unloader ( 6 ) lies against the closing body ( 5   b ) during a first section (K 1 ) of the cycle of crank rotation and prevents its shutting, and in which the unloader ( 6 ) returns during a second section (K 2 ) of the cycle of crank rotation such that the closing body ( 5   b ) shuts, and wherein the control device ( 2 ) preferably comprises a skip regulation, in which the unloader ( 6 ) prevents the shutting of the closing body ( 5   b ) during a complete cycle of crank rotation, and wherein the control device ( 2 ) is configured to steer drive mechanism ( 2   n ) and thereby the unloader ( 6 ) in such a way that the speed of the closing body ( 5   b ) is reduced prior to its seating on the intake valve ( 5 ), in order to seat the closing body ( 5   b ) gently on the intake valve ( 5 ). 
     
     
         13 . Compressor according to  claim 12 , characterised in that, the control device ( 2 ) comprises a mechanism for measuring and/or calculating the pressure progression (P) in the compression space of the reciprocating compressor, and that the control device ( 2 ) is configured such that it drives the closing body ( 5   b ) via the unloader ( 6 ) in free-running mode or with backflow regulation or with skip regulation, in order to open the pressure valve ( 8 ) automatically during a total opening angle (K v ). 
     
     
         14 . Compressor according to  claim 12 , characterised in that, the control device ( 2 ) comprises a displacement sensor ( 2   h ), which captures the displacement of the drive mechanism ( 2   n ) and/or of the unloader ( 6 ) and/or of the closing body ( 5   b ). 
     
     
         15 . Compressor according to  claim 12 , characterised in that, the drive mechanism ( 2   n ) is in the form of an electromagnet ( 2   a ) with solenoid, with a movable magnet anchor ( 2   b ) and a fixedly arranged magnet core ( 2   c ) with magnet coil ( 2   d ), wherein the connection means ( 7 ) is fixedly connected with the magnet anchor ( 2   b ), and wherein the magnet anchor ( 2   b ) is mounted so as to be movable in the direction of extension of the connection rod ( 7 ). 
     
     
         16 . Compressor according to  claim 12 , characterised in that, the drive mechanism ( 2   n ) comprises a steerable damping mechanism ( 2   o ), for damping the speed of the unloader ( 6 ). 
     
     
         17 . Compressor according to  claim 16 , characterised in that the damping mechanism ( 2   o ) is electrically steerable, and that the damping mechanism ( 2   o ) comprises an electrorheological or magnetorheological liquid.