Method for detecting a blocked valve of a coolant compressor and a control system for a coolant compressor

Abstract

A method for detecting a blocked valve of a coolant compressor including a drive unit and a piston-cylinder unit for cyclical compression of a coolant, wherein the drive unit has an electric motor for driving the piston-cylinder unit, monitors the speed (ω) of the electric motor. A maximum speed (ω max ) of the electric motor is initially detected, and the following steps are carried out, as long as the speed (ω) of the electric motor substantially corresponds to the maximum speed (ω max ): determining a maximum value X max of a monitoring parameter (I, T) of the coolant compressor (1); determining a value X t1 of the monitoring parameter (I, T) after a first time period (t1) after determining the maximum value X max ; detecting a blocked valve if X t1 is less than X max and (X max −X t1 )/X max ≥Δ X applies, wherein Δ X is predetermined.

1 . A method for detection of a blocked valve of a coolant compressor ( 1 ) having a drive unit ( 4 ) and a piston/cylinder unit for cyclical compression of a coolant, wherein the drive unit ( 4 ) has an electric motor for drive of the piston/cylinder unit, wherein the speed of rotation (ω) of the electric motor is monitored, wherein first, a maximal speed of rotation (ω max ) of the electric motor is detected and that the following steps are carried out, as long as the speed of rotation (ω) of the electric motor essentially corresponds to the maximal speed of rotation (ω max ):
 determination of a maximal value X max  of a monitoring parameter (I, T) of the coolant compressor ( 1 ); 
 determination of a value X 1  of the monitoring parameter (I, T) after a first time span (t 1 ) after the determination of the maximal value X max ; 
 detection of a blocked valve, if X t1  is less than X max  and (X max −X t1 )/X max ≥Δ X  holds true, wherein Δ X  is predetermined. 
 
     
     
         2 . The method according to  claim 1 , wherein Δ X  is ≥0.2, preferably Δ x  is z  0 . 4 , particularly preferably Δ X  is z  0 . 5 . 
     
     
         3 . Method The method according to  claims 1  to , c  claim 1 , wherein the monitoring parameter is a current (I) consumption by the electric motor or a temperature (T) of control electronics of the coolant compressor ( 1 ), particularly of the electric motor, or of a motor winding of the electric motor. 
     
     
         4 . Method The method according to  claim 1 , wherein the determination of the maximal value X max  takes place only after an initiation time span (t 0 ) after detection of the maximal speed of rotation (ω max ) of the electric motor. 
     
     
         5 . Method The method according to  claim 4 , wherein the initiation time span (t 0 ) amounts to at least 5 min, preferably at least 10 min, particularly preferably at least 15 min. 
     
     
         6 . The method according to  claim 1 , wherein after a verification time span (t 2 ) after detection of the blocked valve, a value X t2  of the monitoring parameter (I, T) is determined, and detection of the blocked valve is verified if X t2  is less than X max  and (X max −X t2 )/X max ≥Δ X  holds true. 
     
     
         7 . The method according to  claim 6 , wherein the verification time span (t 2 ) amounts to 15 s to 5 min, preferably 30 s to 3 min, particularly preferably 45 s to 1 min 30 s. 
     
     
         8 . The method according to  claim 1 , wherein the first time span (t 1 ) amounts to at least 3 h, preferably at least 5 h, particularly preferably at least 6 h. 
     
     
         9 . The method according to  claim 1 , wherein after detection of the blocked valve, a corresponding error message is written into a readable memory provided for this purpose. 
     
     
         10 . The method according to  claim 6 , wherein, wherein after verification of the detection of the blocked valve, a corresponding error message is written into a readable memory provided for this purpose. 
     
     
         11 . An operating method for operating a coolant compressor ( 1 ), the operating method comprising the method according to  claim 1 , wherein the electric motor is stopped after detection of the blocked valve. 
     
     
         12 . The operating method for operating a coolant compressor ( 1 ), the operating method comprising the method according to  claim 6 , wherein the electric motor is stopped after verification of the detection of the blocked valve. 
     
     
         13 . The operating method according to at  claim 11 , wherein the electric motor is restarted after a second time span (t 3 ). 
     
     
         14 . The operating method according to  claim 13 , wherein the second time span (t 3 ) amounts to at least 3 s, preferably at least 6 s, particularly preferably at least 15 s. 
     
     
         15 . The operating method according to  claim 13 , wherein the second time span (t 3 ) amounts to maximally 60 min. 
     
     
         16 . A control system for a coolant compressor ( 1 ), the coolant compressor ( 1 ) comprising a drive unit ( 4 ) and a piston/cylinder unit for cyclical compression of a coolant, wherein the drive unit ( 4 ) has an electric motor for drive of the piston/cylinder unit, and wherein the control system has control electronics, characterized in that wherein the control electronics are set up for carrying out the method according to  claim 1  and/or for carrying out an operating method. 
     
     
         17 . A coolant compressor ( 1 ) having a drive unit ( 4 ) and a piston/cylinder unit for cyclical compression of a coolant, wherein the drive unit ( 4 ) has an electric motor for drive of the piston/cylinder unit, wherein the coolant compressor has the control system according to  claim 16 .