Coating agent pump

Abstract

The disclosure relates to a coating agent pump for conveying a coating agent in a coating installation, in particular for conveying paint in a painting installation, with an electric drive motor for driving the coating agent pump so that the coating agent pump continuously changes its pump position during operation. The disclosure provides a position measuring system for quantitatively detecting the pump position of the coating agent pump.

1 .- 16 . (canceled) 
     
     
         17 . A coating agent pump for conveying a coating agent in a coating installation, having
 a) an electric drive motor for driving the coating agent pump so that the coating agent pump continuously changes its pump position during operation, and   b) means for measuring a position and for quantitatively detecting the pump position of the coating agent pump.   
     
     
         18 . A coating agent pump according to  claim 17 , wherein the position measuring system is integrated in the coating agent pump. 
     
     
         19 . A coating agent pump according to  claim 17 , wherein the position measuring system is separated from the coating agent pump. 
     
     
         20 . A coating agent pump according to  claim 17 , wherein the position measuring system ascertains an absolute value of the pump position in contrast to an incremental value. 
     
     
         21 . A coating agent pump according to  claim 17 , wherein the position measuring system ascertains an incremental value of the pump position in contrast to an absolute value. 
     
     
         22 . A coating agent pump according to  claim 17 , wherein the drive motor is a synchronous motor. 
     
     
         23 . A coating agent pump according to  claim 17 , wherein the drive motor is an asynchronous motor. 
     
     
         24 . A coating agent pump according to  claim 17 , wherein the drive motor is a servomotor which has an integrated position sensor as part of the position measuring system in order to ascertain the position of the drive motor and hence also the pump position. 
     
     
         25 . A coating agent pump according to  claim 17 , wherein a position of a slide which is driven is measured. 
     
     
         26 . A coating agent pump according to  claim 17 , wherein
 a) the position measuring system ascertains the mechanical loading of the drive motor by the coating agent pump by means of a force or torque measurement means, and   b) the position measuring system derives the pump position from the mechanical loading of the drive motor.   
     
     
         27 . A coating agent pump according to  claim 26 , wherein
 a) the position measuring system measures an electrical operating variable of the electric drive motor by means of a force or torque measurement means, and   b) the position measuring system derives from the measured electrical operating variable the mechanical loading of the drive motor by the coating agent pump.   
     
     
         28 . A coating agent pump according to  claim 26 , wherein
 a) the force or torque measurement means has a torque transducer which measures a torque which acts on a drive shaft of the drive motor, and   b) the torque transducer has a strain gauge which is attached to the drive shaft of the drive motor or to a piston of the coating agent pump.   
     
     
         29 . A coating agent pump according to  claim 17 , wherein the coating agent pump has an absolute dispensing inaccuracy of less than 50 ml relative to a swept volume of the piston pump of 1600 cm 3 . 
     
     
         30 . A coating agent pump according to  claim 17 , wherein the coating agent pump is a piston pump with a certain displaced volume, the coating agent pump having a relative dispensing inaccuracy of less than 5‰ relative to the displaced volume. 
     
     
         31 . A coating agent pump according to  claim 17 , wherein
 a) a control unit is provided which is connected on the input side to the position measuring system and on the output side to the electric drive motor, and   b) the control unit actuates the electric drive motor as a function of the pump position ascertained by the position measuring system.   
     
     
         32 . A coating agent pump according to  claim 31 , wherein the control unit drives the drive motor in order to reduce pulsations of the delivery flow such that the piston when passing through its reversal regions moves faster than between the reversal regions. 
     
     
         33 . A coating agent pump according to  claim 17 , wherein
 a) a pressure measurement means is provided in order to measure the coating agent pressure at the exit from the coating agent pump, and   b) the pressure measurement means ascertains the mechanical loading which acts on the drive motor from the coating agent pump, and   c) the pressure measurement means derives the coating agent pressure from the mechanical loading of the drive motor.   
     
     
         34 . A coating agent pump according to  claim 17 , wherein
 a) a monitoring system is provided in order to recognise a malfunction or wear of the coating agent pump, and   b) the monitoring system ascertains relationships between measured variables of the pump position, of the coating agent pressure, of the mechanical loading of the drive motor and/or of the delivery rate of the coating agent pump, and   c) the monitoring system generates a warning signal in the event of a change in the relationships between the measured variables over time.   
     
     
         35 . A coating agent pump according to  claim 17 , wherein
 a) a pressure limiter is provided for limiting the pressure at the exit from the coating agent pump, and   b) the pressure limiter limits an electrical operating variable of the coating agent pump in order to prevent excessive pressure.   
     
     
         36 . A coating agent pump according to  claim 37 , wherein:
 the coating agent pump is a double-piston pump with two opposed pistons which are displaceable in one cylinder in each case, and   b) the pistons are horizontally displaceable and the drive motor has a vertical drive shaft between the two pistons,   c) the drive motor drives the two pistons by means of a rotatable cam disc, and   d) a planetary gear mechanism is arranged between the drive motor and the cam disc.   
     
     
         37 . A coating agent pump according to  claim 37 , wherein at least one of the drive motor and electronics components is housed in an explosion-protected housing.