Pump arrangement and corresponding operating method

Abstract

A pump arrangement, in particular in a coating installation for the coating of components, such as a painting installation for the painting of motor vehicle body components, is provided. The pump arrangement includes a plurality of adjustable pumps for delivering a coating agent, e.g. for delivering a sealing agent for the sealing of weld seams on a motor vehicle body component. The pumps are connected in parallel such that the pumps extract the coating agent for delivery from a common inlet line and deliver said coating agent into a common outlet line. The arrangement further includes a control device for the open-loop or closed-loop control of one fluid variable at the outlet of the individual pumps, respectively, wherein the control device actuates the individual pumps individually, and/or a monitoring unit, which switches the pumps on and off non-simultaneously.

Claims

1. A pump arrangement comprising: a common outlet line; an outlet pressure sensor in the common outlet line; a plurality of pumps configured to deliver a coating agent, each of the plurality of pumps having an adjustable pumping power, the plurality of pumps being fluidly connected in parallel to at least one of the common outlet line and a common inlet line; a pump sensor at each of the plurality of pumps, the pump sensors configured to detect whether the respective one of the plurality of pumps is working; and a closed-loop control device configured to actuate each of the plurality of pumps individually, the control device configured to adjust a fluid variable at an outlet of each of the plurality of pumps to a respective nominal value; wherein the closed-loop control device comprises an actuator for each of the plurality of pumps, respectively, the actuators respectively configured to operate the respective one of the plurality of pumps with a variable control variable to adjust the fluid variable to the respective nominal value; wherein the control device is configured to switch each of the plurality of pumps on and off non-simultaneously; wherein the control device is configured to determine whether the respective ones of the plurality of pumps that are switched on are working and issues a warning signal if any one or more of the respective ones of the plurality of pumps that are switched on is not actually working; wherein the control device is configured to query the outlet pressure sensor for a pressure value in the common outlet line, and is further configured to switch on an additional one of the plurality of pumps if the pressure value is below a predetermined minimum pressure; and the plurality of pumps are pneumatically driven, and the actuators are each a continuous valve configured to control each of the plurality of pneumatically driven pumps with an adjustable compressed air flow.

2. The pump arrangement according to claim 1, wherein the fluid variable is one of a coating agent pressure and a fluid flow at each of the plurality of pumps, respectively.

3. The pump arrangement according to claim 2, wherein the closed-loop control device is configured to adjust the fluid variable for each of the plurality of pumps to a common nominal value, respectively.

4. The pump arrangement according to claim 3, wherein the closed-loop control device includes a measuring element for each of the plurality of pumps, respectively, the measuring element configured to determine a value of the fluid variable at the outlet of the each of the plurality of pumps, respectively.

5. The pump arrangement according to claim 4, wherein the measuring element for each of the plurality of pumps is a pressure sensor configured to determine the coating agent pressure at the outlet of the respective one of the plurality of pumps.

6. The pump arrangement according to claim 1, the closed-loop control device comprises a controller, the controller being connected to the actuators of each of the plurality of pumps and respectively controlling the actuators.

7. The pump arrangement according to claim 4, wherein the closed-loop control device comprises a controller, the controller being connected with the measuring elements of each of the plurality of pumps and registering the measured values of the fluid variable at each of the plurality of pumps.

8. The pump arrangement according to claim 1, wherein, if the pressure value is below the predetermined minimum pressure for a predetermined minimum time period, the control device is configured to switch off all of the plurality of pumps.

9. The pump arrangement according to claim 1, further comprising a speed sensor for each of the plurality of pumps, wherein the control device is configured to query the speed sensors, respectively, and thereby determines the pumping speeds of each of the plurality of pumps, respectively, the control device activating an additional one of the plurality of pumps if at least one of the measured pumping speeds exceeds a predetermined first maximum value, the control device switching off the respective ones of the plurality of pumps for which the pumping speed exceeds a predetermined second maximum value, the second maximum value being greater than the first maximum value.

10. A method for operation of a pump arrangement with a plurality of pumps, which are connected in parallel at at least one of an inlet side and an outlet side, the method comprising: determining a fluid variable at an outlet of each of the plurality of pumps; controlling each of the plurality of pumps toward a respective nominal value of the fluid variable; respectively switching on and/or off the plurality pumps non-simultaneously; switching on a first group of the plurality of pumps and switching off a remaining group of the plurality of pumps; operating the first group for a predetermined operating time; rotating the ones of the plurality of pumps in the first group; comparing an operating variable of the each of the plurality of pumps to a first maximum value and a second maximum value, the second maximum value being greater than the first maximum value; switching on an additional one of the plurality of pumps, if the operating variable exceeds the first maximum value in any of the plurality of pumps; and switching off any of the plurality of pumps in which the operating variable exceeds the second maximum value.

11. The method of claim 10, further comprising: initially switching on of all of the plurality of pumps for an activation period in the range of 1 s-10 s.

12. The method of claim 10, wherein each of the plurality of pumps are piston pumps, configured to operate with a variable piston stroke speed, and the operating variable is a piston stroke speed.

13. The method according to claim 10, further comprising: comparing a coating agent pressure in a common outlet line to a predetermined minimum value; switching on an additional one of the plurality of pumps if the coating agent pressure in the common outlet line is below the predetermined minimum value; and if the coating agent pressure in the common outlet line is below the predetermined minimum value for a predetermined time period, switching off all of the plurality of pumps and issuing a leak warning.

14. A pump arrangement comprising: a plurality of pumps configured to deliver a coating agent, each of the plurality of pumps having an adjustable pumping power, the plurality of pumps being fluidly connected in parallel to at least one of a common outlet line and a common inlet line; the common outlet line and an outlet pressure sensor in the common outlet line; a closed-loop control device configured to actuate each of the plurality of pumps individually, the control device configured to adjust a fluid variable at an outlet of each of the plurality of pumps to a respective nominal value; and a pump sensor at each of the plurality of pumps, the pump sensors configured to detect whether the respective one of the plurality of pumps is working; wherein the control device is configured to switch each of the plurality of pumps on and off non-simultaneously; the control device is configured to determine whether the respective ones of the plurality of pumps that are switched on are working and issues a warning signal if any one or more of the respective ones of the plurality of pumps that are switched on is not actually working; and the control device is configured to query the outlet pressure sensor for a pressure value in the common outlet line, and is further configured to switch on an additional one of the pumps if the pressure value is below a predetermined minimum pressure.

15. A pump arrangement comprising: a plurality of pumps configured to deliver a coating agent, each of the plurality of pumps having an adjustable pumping power, the plurality of pumps being fluidly connected in parallel to at least one of a common outlet line and a common inlet line; a closed-loop control device configured to actuate each of the plurality of pumps individually, the control device configured to adjust a fluid variable at an outlet of each of the plurality of pumps to a respective nominal value; a pump sensor at each of the plurality of pumps, the pump sensors configured to detect whether the respective one of the plurality of pumps is working; and a speed sensor for each of the plurality of pumps; wherein the control device is configured to switch each of the plurality of pumps on and off non-simultaneously; the control device is configured to determine whether the respective ones of the plurality of pumps that are switched on are working and issues a warning signal if any one or more of the respective ones of the plurality of pumps that are switched on is not actually working; and the control device is configured to query the speed sensors, respectively, and thereby determines the pumping speeds of each of the plurality of pumps, respectively, the control device activating an additional pump if at least one of the measured pumping speeds exceeds a predetermined first maximum value, and the control device switching off the respective ones of the plurality of pumps for which the pumping speed exceeds a predetermined second maximum value, the second maximum value being greater than the first maximum value.

16. A method for operation of a pump arrangement with a plurality of pumps, which are connected in parallel at at least one of an inlet side and an outlet side, the method comprising: determining a fluid variable at an outlet of each of the plurality of pumps; controlling each of the plurality of pumps toward a nominal value of the fluid variable; respectively switching on and/or off the plurality pumps non-simultaneously; comparing an operating variable of the each of the plurality of pumps to a first maximum value and a second maximum value, the second maximum value being greater than the first maximum value; switching on an additional one of the plurality of pumps, if the operating variable exceeds the first maximum value in any of the plurality of pumps; and switching off any of the plurality of pumps in which the operating variable exceeds the second maximum value.

17. A method for operation of a pump arrangement with a plurality of pumps, which are connected in parallel at at least one of an inlet side and an outlet side, the method comprising: determining a fluid variable at an outlet of each of the plurality of pumps; controlling each of the plurality of pumps toward a respective nominal value, of the fluid variable; and respectively switching on and/or off the plurality pumps non-simultaneously; comparing a coating agent pressure in a common outlet line to a predetermined minimum value; switching on an additional one of the pumps if the coating agent pressure in the common outlet line is below the predetermined minimum value; and if the coating agent pressure in the common outlet line is below the predetermined minimum value for a predetermined time period, switching off all the pumps and issuing a leak warning.

18. A pump arrangement comprising: a plurality of pumps configured to deliver a coating agent, each of the plurality of pumps having an adjustable pumping power, the plurality of pumps being fluidly connected in parallel to at least one of a common outlet line and a common inlet line; and a closed-loop control device configured to actuate each of the plurality of pumps individually, the control device configured to adjust a fluid variable at an outlet of each of the plurality of pumps to a respective nominal value; wherein the closed-loop control device comprises an actuator for each of the plurality of pumps, respectively, the actuators respectively configured to operate the respective on of the plurality of pumps with a variable control variable to adjust the fluid variable to the respective nominal value; and the plurality of pumps are pneumatically driven, and the actuators are each a continuous valve configured to control each of the plurality of pneumatically driven pumps with an adjustable compressed air flow; wherein the control device is configured to switch each of the plurality of pumps on and off non-simultaneously; a pump sensor at each of the plurality of pumps, the pump sensors configured to detect whether the respective one of the plurality of pumps is working, wherein the control device is configured to determine whether the respective ones of the plurality of pumps that are switched on are working and issues a warning signal if any one or more of the respective ones of the plurality of pumps that are switched on is not actually working; wherein the common outlet line has an outlet pressure sensor in the common outlet line, and; wherein the control device is configured to query the outlet pressure sensor for a pressure value in the common outlet line, and is further configured to switch on an additional one of the plurality of pumps if the pressure value is below a predetermined minimum pressure.

19. The pump arrangement according to claim 18, wherein, if the pressure value is below the predetermined minimum pressure for a predetermined minimum time period, the control device is configured to switch off all of the plurality of pumps.

20. A pump arrangement comprising: a plurality of pumps configured to deliver a coating agent, each of the plurality of pumps having an adjustable pumping power, the plurality of pumps being fluidly connected in parallel to at least one of a common outlet line and a common inlet line; and a closed-loop control device configured to actuate each of the plurality of pumps individually, the control device configured to adjust a fluid variable at an outlet of each of the plurality of pumps to a respective nominal value; wherein the closed-loop control device comprises an actuator for each of the plurality of pumps, respectively, the actuators respectively configured to operate the respective on of the plurality of pumps with a variable control variable to adjust the fluid variable to the respective nominal value; and the plurality of pumps are pneumatically driven, and the actuators are each a continuous valve configured to control each of the plurality of pneumatically driven pumps with an adjustable compressed air flow; wherein the control device is configured to switch each of the plurality of pumps on and off non-simultaneously; a pump sensor at each of the plurality of pumps, the pump sensors configured to detect whether the respective one of the plurality of pumps is working, wherein the control device is configured to determine whether the respective ones of the plurality of pumps that are switched on are working and issues a warning signal if any one or more of the respective ones of the plurality of pumps that are switched on is not actually working; a speed sensor for each of the plurality of pumps, wherein the control device is configured to query the speed sensors, respectively, and thereby determines the pumping speeds of each of the plurality of pumps, respectively, the control device activating an additional one of the plurality of pumps if at least one of the measured pumping speeds exceeds a predetermined first maximum value, the control device switching off the respective ones of the plurality of pumps for which the pumping speed exceeds a predetermined second maximum value, the second maximum value being greater than the first maximum value.

21. A method for operation of a pump arrangement with a plurality of pumps, which are connected in parallel at at least one of an inlet side and an outlet side, the method comprising: determining a fluid variable at an outlet of each of the plurality of pumps; controlling each of the plurality of pumps toward a respective nominal value of the fluid variable; respectively switching on and/or off the plurality pumps non-simultaneously; switching on a first group of the plurality of pumps and switching off a remaining group of the plurality of pumps; operating the first group for a predetermined operating time; and rotating the ones of the plurality of pumps in the first group, comparing an operating variable of the each of the plurality of pumps to a first maximum value and a second maximum value, the second maximum value being greater than the first maximum value; switching on an additional one of the plurality of pumps, if the operating variable exceeds the first maximum value in any of the plurality of pumps; and switching off any of the plurality of pumps in which the operating variable exceeds the second maximum value.

22. The method of claim 21, wherein each of the plurality of pumps are piston pumps, configured to operate with a variable piston stroke speed, and the operating variable is a piston stroke speed.

23. A method for operation of a pump arrangement with a plurality of pumps, which are connected in parallel at at least one of an inlet side and an outlet side, the method comprising: determining a fluid variable at an outlet of each of the plurality of pumps; controlling each of the plurality of pumps toward a respective nominal value of the fluid variable; respectively switching on and/or off of the plurality pumps non-simultaneously; switching on a first group of the plurality of pumps and switching off a remaining group of the plurality of pumps; operating the first group for a predetermined operating time; and rotating the ones of the plurality of pumps in the first group, comparing a coating agent pressure in a common outlet line to a predetermined minimum value; switching on an additional one of the plurality of pumps if the coating agent pressure in the common outlet line is below the predetermined minimum value; and if the coating agent pressure in the common outlet line is below the predetermined minimum value for a predetermined time period, switching off all of the plurality of pumps and issuing a leak warning.

Description

DRAWINGS

(1) The present disclosure is further outlined in more detail herein based on the figures, together with the description of an exemplary implementations of the present disclosure. The figures show:

(2) FIG. 1 A schematic illustration of a pump arrangement according to the present disclosure,

(3) FIG. 2 A schematic diagram of the pump arrangement from FIG. 1,

(4) FIG. 3 A flow diagram to illustrate the operating method according to the present disclosure with a cyclical rotation of the activated pumps,

(5) FIG. 4 A flow diagram to illustrate a speed control of the individual pumps, and

(6) FIG. 5 A flow diagram to illustrate leak monitoring according to the present disclosure.

DETAILED DESCRIPTION

(7) FIG. 1 shows a pump arrangement 1, which is used in a painting installation for painting motor vehicle body components in order to pump a sealing agent (e.g. PVC: polyvinylchloride) to multiple application robots, which are not shown in the drawing, and to apply the sealing agent onto seams (e.g. flanged seams, weld seams) on the motor vehicle body components that are to be painted.

(8) Below the broken line in FIG. 1 there is a material supply chamber, also referred to as “PVC chamber”. While the region inside the broken line is situated close to the painting line or paint booth, it is outside the painting line or paint booth.

(9) The pump arrangement 1 extracts the sealing agent from the material supply chamber via a forward line 2.

(10) The forward line 2 opens into an inlet line 3, which supplies a plurality of parallel-connected pumps 4.1-4.7 with sealing agent.

(11) A return line 5 further branches off from the common inlet line 3 of the pumps 4.1-4.7 in order to allow circulation of material between the material supply chamber and the pump arrangement 1.

(12) The pumps 4.1-4.7 are respectively connected at the outlet side via a non-return valve 6.1-6.7 with a common outlet line 7, i.e. the pumps 4.1-4.7 extract the sealing agent from the common inlet line 3 and pump the sealing agent into the common outlet line 7.

(13) Two forward lines 8, 9 run off from the common outlet line 7, said forward lines conveying the sealing agent to the individual application robots. In this way the two forward lines 8, 9 supply the application robots on opposite sides of the painting line. The forward line 8 therefore supplies the application robots on the one side of the painting line, while the forward line 9 supplies the application robots on the other side of the painting line.

(14) The individual pumps 4.1-4.7 are respectively pneumatically driven. For this purpose, the pumps 4.1-4.7 are respectively connected, via a 2/2-way solenoid valve 10.1-10.7 and a proportional valve 11.1-11.7, to a common 2/2-way solenoid valve 12 with a compressed air supply 13.

(15) The 2/2-way solenoid valve 12 is able to either enable or disable the compressed air for all the pumps 4.1-4.7. This allows common switching on and/or off of the pumps 4.1-4.7 by the 2/2-way solenoid valve 12.

(16) The individual pumps 4.1-4.7 can also be switched on and/or off individually, by opening or closing the respective 2/2-way solenoid valve 10.1-10.7.

(17) Furthermore, the pumping capacity of the individual pumps 4.1-4.7 can also be individually adjusted, namely via appropriate control of the individual proportional valves 11.1-11.7.

(18) A pressure sensor 14.1-14.7 is respectively arranged downstream of each of the pumps 4.1-4.7, the individual pressure sensors 14.1-14.7 measuring in each case the outlet pressure of the individual pumps 4.1-4.7.

(19) An initiator 15.1-15.7 is further arranged in each of the pumps 4.1-4.7 to monitor the stroke of the individual pumps 4.1-4.7. Firstly, the initiators 15.1-15.7 allow monitoring of the pumping speeds of the individual pumps 4.1-4.7, as will described in detail below. Secondly, the initiators 4.1-4.7 also allow checking of whether the individual pumps 4.1-4.7 are working.

(20) In some implementations, a pressure sensor 16 is assigned to the common inlet line 3 of the pumps 4.1-4.7 to measure the pressure in the inlet line 3.

(21) Moreover, the common inlet line 3 of the pumps 4.1-4.7 further comprises a temperature sensor 17, which measures the temperature of the sealing agent in the inlet line 3.

(22) A pressure sensor 18 and a temperature sensor 19 are also arranged in the outlet line 7 to measure the pressure and temperature respectively of the sealing agent in the outlet line 7. In addition, a further pressure sensor 20 is situated in the outlet line 7, said pressure sensor delivering an electrical pressure signal to a control, as described in detail below.

(23) Finally, the pump arrangement 1 also comprises a return line 21 and two pneumatically driven isolation valves 22, 23. The isolation valve 22 is closed in production mode and opened in circulation mode. Conversely, the isolation valve 23 is opened in production mode and closed in circulation mode. In this case, production mode is the operating condition, in which the connected application robots demand sealing agent, i.e. in normal coating operation. Circulation mode, on the other hand, is an operating condition, in which the connected application robots do not demand any sealing agent, for example during overnight or weekend shutdown or during maintenance outages.

(24) FIG. 2 shows a schematic view of the pump arrangement 1 described above and illustrated in FIG. 1. Further to the illustration in FIG. 1, this also shows a control device 24, which includes a closed-loop control device and a monitoring unit.

(25) At the inlet side, the control device 24 is connected to the pressure sensors 14.1-14.2, to measure the pressure upstream behind the individual pumps 4.1-4.7, which allows control of the outlet pressure of the individual pumps 4.1-4.7, as described in detail below.

(26) In addition, the control device 24 is connected at the inlet side with the temperature sensor 17, the pressure sensor 16, the pressure sensor 18 and the temperature sensor 20, in order to be able to take account of the readings of these sensors in the control of the pump arrangement 1.

(27) At the outlet side, the control device 24 is connected to the two isolation valves 22, 23 and to the 2/2-way solenoid valve 12, to control the operation of the pump arrangement 1, as described in further detail herein.

(28) The control device 24 is further connected at the outlet side with the proportional valves 11.1-11.7, in order to control the individual pumps 4.1-4.7 in keeping with the control setting.

(29) Finally, the control device 24 is also connected at the outlet side with the 2/2-way solenoid valves 10.1-10.7 of the individual pumps 4.1-4.7, in order to be able to switch the individual pumps 4.1-4.7 on or off individually, as will also be described in detail below.

(30) As mentioned above, the control device 24 contains a controller to control the outlet pressure of the individual pumps 4.1-4.7. To do this, the control device 24 respectively registers actual values of the individual pumps 4.1-4.7 via the pressure sensors 14.1-14.2 and compares the measured actual values with a predetermined, uniform nominal pressure value. From this, the control device 24 calculates a nominal/actual variance between the nominal value and the actual value of the individual pumps 4.1-4.7. As a function of this nominal/actual variance, the control device 24 then controls the individual proportional valves 11.1-11.7 individually with a control signal, in order to adjust the actual outlet pressure value of the individual pumps 4.1-4.7 individually for each of the pumps 4.1-4.7 to the nominal value.

(31) Moreover, the control device 24 is able to switch the individual pumps 4.1-4.7 on or off individually. This can be done using the operating method illustrated in the form of a flow diagram in FIG. 3, in order to switch on the individual pumps 4.1-4.7 on a cyclical basis, as described below.

(32) In a first step S1, the operator of the pump arrangement 1 inputs a number n of pumps to start operation. The number n of pumps required depends upon the capacity demanded by the connected application robots.

(33) In a step S2, the operator of the pump arrangement 1 then inputs a cycle time T for rotating the pumps 4.1-4.7 that are switched on.

(34) In a step S3, all pumps 4.1-4.7 are then briefly switched on, in order to move the coating material in the stub lines to the individual application robots.

(35) In a step S4, the first n pumps to start operation are then selected. For example, for a number n=4, pumps 4.1-4.4 can be selected.

(36) In a subsequent step S5, the selected n pumps are then switched on, while the remaining pumps remain switched off. For example, for a number n=4, pumps 4.1-4.4 can be switched on, while pumps 4.5-4.7 remain switched off.

(37) In a step S6, continuous monitoring takes place to check whether the predetermined cycle time T has elapsed.

(38) If it has, the next n pumps are then selected in a step S7. In the example outlined above, the pumps 4.2-4.5 can then be selected for subsequent activation, while pumps 4.1 and 4.6, 4.7 remain switched off.

(39) Finally one passes to step S5, in which the selected pumps are then switched on or switched off.

(40) In this manner all pumps 4.1-4.7 are switched on in a cyclical sequence, wherein a number of the pumps 4.1-4.7 always remain switched off, unless the capacity demanded requires that all pumps 4.1-4.7 be switched on. This cyclical rotation of the activated pumps is advantageous, since it ensures even wear of the pumps 4.1-4.7.

(41) Moreover, the control device 24 allows an operating method, which is illustrated in the form of a simplified flow diagram in FIG. 4 and is described below.

(42) In a step S1, the stroke speed v.sub.STROKE1, . . . , v.sub.STROKE7 of all pumps 4.1-4.7 is initially measured. This measurement can be done, for example, with the initiators 15.1-15.7.

(43) In a further step S2, the maximum stroke speed v.sub.MAX of all pumps 4.1-4.7 is then measured.

(44) In a step S3, it is then checked whether this maximum stroke speed v.sub.MAX exceeds a predetermined maximum value v.sub.MAX1.

(45) If it does, then, in a step S4, an additional pump 4.1-4.7 is activated, in order to reduce the stroke speed v.sub.MAX to below the predetermined maximum value v.sub.MAX1.

(46) In a step S5, it is then checked whether the maximum pumping speed v.sub.MAX exceeds a predetermined second maximum value v.sub.MAX2.

(47) If it does, then, in a step S6, those pumps in which the stroke speed v.sub.MAX exceeds the predetermined maximum value v.sub.MAX2 are switched off and a warning is issued.

(48) This speed monitoring and optional switching on of additional pumps should prevent the pumping speed going above the predetermined limits.

(49) Finally, the control device 24 allows a further operating method, which is schematically illustrated in the form of a flow diagram in FIG. 5 and allows leak detection.

(50) In a step S1, a timer t=0 is initialised.

(51) In a step S2, a pressure p is then measured in the outlet line 7, which can be done with the pressure sensor 20.

(52) In a step S3, the measured pressure p is then compared with a predetermined minimum value p.sub.MIN.

(53) If the measured pressure p is below the predetermined minimum pressure p.sub.MIN, then, in a step S4, it is checked whether the actual value t of the time exceeds a predetermined time value T. If it does not, the control device 24 attempts to increase the excessively low pressure, in that an additional pump 4.1-4.7 is switched on in a step S6. In a step S7, the pump response is then awaited and, upon this response, the pressure p is then re-measured in a step S2.

(54) If the pressure check reveals that the measured pressure p is above the minimum pressure p.sub.MIN after switching on of an additional pump, then no further action is required.

(55) On the other hand, if the pressure check reveals that the pressure is still below the predetermined minimum pressure p.sub.MIN, then, in a step S4, it is checked whether the excessively low pressure has already persisted for the predetermined time period T.

(56) If it has, this indicates the presence of a leak. In a step S5, all pumps 4.1-4.7 are switched off, as required, and a leak warning is issued.

(57) The present disclosure is not limited to the exemplary implementations described above. Rather, there are a large number of possible variants and adaptations that similarly make use of the principles of the present disclosure.