Method for compressing a gas, computing unit and multi-stage piston compressor

Abstract

A method for compressing a gas by means of a multi-stage piston compressor is disclosed, wherein, if an inlet pressure of a first compression stage exceeds a threshold value, the gas is at least partially, in particular completely, branched off before the first compression stage and fed to a second compression stage, which directly follows the first compression stage. A computing unit for performing the method to such a multi-stage piston compressor are further disclosed.

1 . A method for compressing a gas by means of a multi-stage piston compressor,
 wherein the gas is diverted at least partially upstream of the first compression stage and fed to a second compression stage, which directly follows the first compression stage, if an inlet pressure of the first compression stage exceeds a threshold value.   
     
     
         2 . The method according to  claim 1 , wherein the stroke (h 1 ) of a piston of the piston compressor, which is assigned to the first compression stage, is furthermore reduced. 
     
     
         3 . The method according to  claim 2 , wherein the stroke (h 1 ) is reduced in dependence on a residual pressure after a reexpansion in the first compression stage and/or an inlet pressure of the second compression stage. 
     
     
         4 . The method according to  claim 3 , wherein the reduction of the stroke (h 1 ) is determined based on stored values for the residual pressure and/or the inlet pressure of the second compression stage. 
     
     
         5 . The method according to  claim 1 , wherein the gas is diverted upstream of the first compression stage and fed to the second compression stage in that a first valve in a first flow path leading to the first compression stage is at least partially closed and a second valve in a second flow path leading from the first flow path to the second compression stage is at least partially opened. 
     
     
         6 . The method according to  claim 5 , wherein an inlet valve of the second compression stage is used as the first valve. 
     
     
         7 . The method according to  claim 1 , wherein at least one electric linear motor is used for moving pistons in the piston compressor. 
     
     
         8 . A computing unit, for carrying out a method for compressing a gas by means of a multi-stage piston compressor, wherein the gas is diverted at least partially upstream of the first compression stage and fed to a second compression stage, which directly follows the first compression stage, if an inlet pressure of the first compression stage exceeds a threshold value. 
     
     
         9 . A multi-stage reciprocating piston compressor with a gas inlet, a first compression stage and a second compression stage,
 wherein a first valve is arranged in a first flow path leading to a gas inlet of the first compression stage,   wherein a second flow path branches off the first flow path upstream of the first valve and leads to a gas inlet of the second compression stage, and   wherein a second valve is arranged in the second flow path.   
     
     
         10 . The multi-stage reciprocating piston compressor according to  claim 9 , wherein the inlet valve of the first compression stage forms the first valve. 
     
     
         11 . The multi-stage reciprocating piston compressor according to  claim 9  with at least one electric linear motor for moving pistons of the reciprocating piston compressor. 
     
     
         12 . The multi-stage reciprocating piston compressor according to  claim 9  further comprising a computing unit for carrying out a method for compressing a gas by means of a multi-stage piston compressor, wherein the gas is diverted at least partially upstream of the first compression stage and fed to a second compression stage, which directly follows the first compression stage, if an inlet pressure of the first compression stage exceeds a threshold value. 
     
     
         13 . The method according to  claim 1  wherein the gas is diverted completely upstream of the first compression stage.