Pump arrangement

Abstract

A pump arrangement for pumping a liquid, in particular a liquid contaminated with dirt particles, the pump arrangement having at least one working chamber ( 1, 2, 11, 12 ) and at least one delivery piston ( 3, 4, 13 ), and at least one inlet valve ( 7 ) and at least one outlet valve ( 8 ), and the delivery piston ( 3, 4, 13 ) being movable in order to suck liquid into the working chamber ( 1, 2, 11, 12 ) through the inlet valve ( 7 ) and to eject liquid out of the working chamber ( 1, 2, 11, 12 ) through the outlet valve ( 8 ), and the pump arrangement having a wear-monitoring device ( 40 ) for monitoring the wear on the inlet valve ( 7 ) and/or outlet valve ( 8 ) with at least one pressure sensor ( 41 ) and one pressure evaluation unit ( 42 ) for processing pressure measurement values output from the pressure sensor ( 41 ), wherein the pump arrangement, for the purpose of moving the delivery piston ( 3, 4, 13 ), has a drive fluid system ( 20 ) that can be operated with a drive fluid, and the pressure sensor ( 41 ) of the wear-monitoring device ( 40 ) is arranged to detect the pressure of the drive fluid in the drive fluid system ( 20 ).

1 . A pump arrangement for pumping a liquid, the pump arrangement comprising at least one working chamber, at least one delivery piston, at least one inlet valve, and at least one outlet valve, the delivery piston being movable in order to suck liquid into the working chamber through the inlet valve and to eject liquid out of the working chamber through the outlet valve, a drive fluid system that is operable with a drive fluid that moves the delivery piston, a wear-monitoring device for monitoring wear on at least one of the inlet valve or outlet valve including at least one pressure sensor and one pressure evaluation unit for processing pressure measurement values output from the pressure sensor, and the pressure sensor of the wear-monitoring device is arranged to detect a pressure of the drive fluid in the drive fluid system. 
     
     
         2 . The pump arrangement as claimed in  claim 1 , further comprising a drive piston mounted movably in a drive cylinder of the drive fluid system, the drive piston being mechanically coupled to the at least one delivery piston. 
     
     
         3 . The pump arrangement as claimed in  claim 2 , wherein the pump arrangement has two delivery pistons which are connected to the drive piston that is mounted movably in the drive cylinder of the drive fluid system. 
     
     
         4 . The pump arrangement as claimed in  claim 3 , wherein the two delivery pistons are connected rigidly to the drive piston. 
     
     
         5 . The pump arrangement as claimed in  claim 1 , wherein the delivery piston is a plunger. 
     
     
         6 . The pump arrangement as claimed in  claim 1 , wherein the delivery piston has at least one peripheral seal. 
     
     
         7 . The pump arrangement as claimed in  claim 6 , wherein the pump arrangement has first and second working chambers, the at least one inlet valve comprises first and second inlet valves, the at least one outlet valve comprises first and second outlet valves, the delivery piston separates the first working chambers and the second working chambers from each other, and each of the working chambers is assigned a respective one of the first and second inlet valves and a respective one of the first and second outlet valves. 
     
     
         8 . The pump arrangement as claimed in  claim 1 , wherein the wear-monitoring device comprises a signaling unit for informing a user of a presence of wear on at least one of the at least one inlet valve or the at least one outlet valve, the wear having been determined by the pressure evaluation unit. 
     
     
         9 . The pump arrangement as claimed in  claim 1 , wherein the pump arrangement has at least one proximity switch for detecting an end position of the delivery piston. 
     
     
         10 . The pump arrangement as claimed in  claim 2 , wherein the pump arrangement has at least one proximity switch for detecting an end position of the drive piston mounted movably in the drive cylinder of the drive fluid system. 
     
     
         11 . The pump arrangement as claimed in  claim 1 , wherein the pump arrangement has exactly one pressure sensor for measuring the pressure of the drive fluid, the pressure sensor being arranged between a drive fluid pump and a switching valve for controlling a direction of movement of the at least one delivery piston. 
     
     
         12 . The pump arrangement as claimed in  claim 11 , wherein the drive fluid pump is volume-regulated. 
     
     
         13 . The pump arrangement as claimed in  claim 1 , wherein the pump arrangement is adapted to pump liquid contaminated with dirt particles. 
     
     
         14 . A method for monitoring wear on at least one of the at least one inlet valve or at least one outlet valve in the pump arrangement as claimed in  claim 1 , comprising forming with the pressure evaluation unit at least one characteristic value in each case from pressure measurement values processed during a stroke operation of the delivery piston, and evaluating the characteristic values of a sequence of stroke operations.