fig1 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 . below the broken line in fig1 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 . the pump arrangement 1 extracts the sealing agent from the material supply chamber via a forward line 2 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . 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 . fig2 shows a schematic view of the pump arrangement 1 described above and illustrated in fig1 . further to the illustration in fig1 , this also shows a control device 24 , which includes a closed - loop control device and a monitoring unit . 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 . 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 . 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 . 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 . 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 . 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 . 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 fig3 , in order to switch on the individual pumps 4 . 1 - 4 . 7 on a cyclical basis , as described below . in a first step s 1 , 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 . in a step s 2 , 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 . in a step s 3 , 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 . in a step s 4 , 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 . in a subsequent step s 5 , 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 . in a step s 6 , continuous monitoring takes place to check whether the predetermined cycle time t has elapsed . if it has , the next n pumps are then selected in a step s 7 . 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 . finally one passes to step s 5 , in which the selected pumps are then switched on or switched off . 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 . moreover , the control device 24 allows an operating method , which is illustrated in the form of a simplified flow diagram in fig4 and is described below . in a step s 1 , the stroke speed v stroke1 , . . . , v 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 . in a further step s 2 , the maximum stroke speed v max of all pumps 4 . 1 - 4 . 7 is then measured . in a step s 3 , it is then checked whether this maximum stroke speed v max exceeds a predetermined maximum value v max1 . if it does , then , in a step s 4 , an additional pump 4 . 1 - 4 . 7 is activated , in order to reduce the stroke speed v max to below the predetermined maximum value v max1 . in a step s 5 , it is then checked whether the maximum pumping speed v max exceeds a predetermined second maximum value v max2 . if it does , then , in a step s 6 , those pumps in which the stroke speed v max exceeds the predetermined maximum value v max2 are switched off and a warning is issued . this speed monitoring and optional switching on of additional pumps should prevent the pumping speed going above the predetermined limits . finally , the control device 24 allows a further operating method , which is schematically illustrated in the form of a flow diagram in fig5 and allows leak detection . in a step s 2 , a pressure p is then measured in the outlet line 7 , which can be done with the pressure sensor 20 . in a step s 3 , the measured pressure p is then compared with a predetermined minimum value p min . if the measured pressure p is below the predetermined minimum pressure p min , then , in a step s 4 , 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 s 6 . in a step s 7 , the pump response is then awaited and , upon this response , the pressure p is then re - measured in a step s 2 . if the pressure check reveals that the measured pressure p is above the minimum pressure p min after switching on of an additional pump , then no further action is required . on the other hand , if the pressure check reveals that the pressure is still below the predetermined minimum pressure p min , then , in a step s 4 , it is checked whether the excessively low pressure has already persisted for the predetermined time period t . if it has , this indicates the presence of a leak . in a step s 5 , all pumps 4 . 1 - 4 . 7 are switched off , as required , and a leak warning is issued . 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 .