EP3246568A1 - Pump assembly - Google Patents

Abstract

Pump arrangement for pumping a, in particular contaminated with dirt particles, liquid, the pump assembly at least one working space (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), for sucking liquid through the inlet valve (7) into the working space (1, 2, 11, 12) and for discharging liquid through the outlet valve (8) through the working space (1, 2, 11, 12), and the pump assembly comprises a wear monitoring device (40) for monitoring the wear of the inlet valve (7) and / or outlet valve (8) with at least one pressure sensor (41) and a Pressure evaluation unit (42) for processing pressure readings issued by the pressure transducer (41), wherein the pump arrangement for moving the delivery piston (3, 4, 13) comprises a drive fluid system (FIG. 20), and the pressure transducer (41) of the wear monitor (40) is arranged to sense the pressure of the drive fluid in the drive fluid system (20). (Fig. 1)

Description

The present invention relates to a pump arrangement for pumping a, in particular contaminated with dirt particles, liquid, the pump assembly having at least one working space and at least one delivery piston, and at least one inlet valve and at least one outlet valve, and the delivery piston, for sucking liquid through the inlet valve in the working space and for discharging liquid through the outlet valve from the working space, movable, and the pump assembly comprises a wear monitoring device for monitoring the wear of the inlet valve and / or outlet valve with at least one pressure transducer and a pressure evaluation unit for processing issued by the pressure transducer pressure readings. Furthermore, the invention also relates to a method for monitoring the wear of at least one inlet valve and / or at least one outlet valve of a pump arrangement.

Pump arrangements for pumping, in particular contaminated with dirt particles, liquids are, for example, for pumping waste water from channels, storage tanks, etc. or for flushing sewers, boreholes, etc. used. Frequently, dirt particles in the form of solid particles (eg sand or stones) or in the form of fibers are present. In particular, dirt particles from solids can have an abrasive effect and lead to wear of the components of the pump arrangement, for example the inlet valves and / or outlet valves. If dirt particles are trapped in the inlet and / or outlet valve when closing the inlet and / or outlet valve, locally high flow velocities can occur. Further, flowing through the inlet and / or outlet dirt particles can cause wear and thus to a deterioration of the functioning of the Inlet valve and / or exhaust valve lead. Due to the wear of the intake valves and / or exhaust valves ultimately the capacity of the pump assembly is reduced, which is why the intake valves and / or exhaust valves must be overhauled or even completely replaced when wear occurs.

In the WO 2007/072385 A2 is a pump assembly of the type mentioned for flushing boreholes with a driven by a rotating crankshaft delivery piston shown. The proposed according to this document wear monitoring device allows monitoring of the wear of the intake and / or the exhaust valve by means disposed in the working space pressure and acceleration sensors. In a downstream of the working space high pressure section another pressure transducer is arranged. The pressure and acceleration sensors are in direct contact with the fluid to be delivered. When pumping, in particular contaminated with dirt particles, liquid pressure and acceleration sensors are thus exposed directly to the abrasive effect of the medium.

The object of the invention is to provide an advantageous pump arrangement of the type mentioned, which is also suitable for pumping heavily contaminated with dirt particles liquids.

According to the invention, this is achieved with a pump arrangement having the features of patent claim 1.

In the pumping arrangement according to the invention, it is provided that the pumping arrangement for moving the delivery piston comprises a drive fluid system operable with a drive fluid, and the pressure sensor of the wear monitoring device is arranged for detecting the pressure of the drive fluid in the drive fluid system.

It was found that during the pumping of the Pressure sensor distinguished pressure readings of the drive fluid at a defective inlet valve and / or outlet valve output from the pressure transducer pressure readings at an intact intake valves and / or exhaust valve. As a result, it is possible with the pump arrangement according to the invention to realize wear of the inlet valve and / or the outlet valve by indirect monitoring with the at least one pressure transducer arranged in the drive fluid circuit.

By detecting the pressure of the drive fluid in the drive fluid system, a wear of the at least one inlet valve and / or the at least one outlet valve can thus be detected without the pressure sensor being in direct contact with the liquid contaminated, in particular with dirt particles.

Conveniently, the drive fluid is a liquid medium, in particular hydraulic oil. In principle, it would also be conceivable and possible to use a gaseous propellant fluid, e.g. Ambient air.

The drive fluid system could be designed as an open drive fluid system. An open drive fluid system could be e.g. prove beneficial in the use of ambient air as the drive fluid, in which case preferably ambient air is removed from the atmosphere and compressed and in turn fed to the atmosphere after use in the drive fluid system.

Most preferably, the drive fluid system is a closed drive fluid system wherein the drive fluid is conveyed in a closed loop. In such cases, one could also speak of a drive fluid circuit.

Preferably, a drive piston is movably mounted in a drive cylinder of the drive fluid system, which is mechanically coupled to the at least one delivery piston. The drive piston and the at least one delivery piston For example, could be mechanically coupled to each other by means of a common piston rod. An articulated mechanical coupling of the drive piston and the at least one delivery piston is conceivable and possible. A direct interconnection of drive and delivery pistons is possible.

The delivery piston could generally also be referred to as a displacement body. The volume of the working space is increased by the movement of the delivery piston for sucking liquid into the working space and reduced to eject liquid from the working space. Conveniently, the delivery piston is mounted in a delivery cylinder, preferably linear, movable. The working space is then in the delivery cylinder.

In preferred embodiments according to the invention it is provided that the pump arrangement comprises two delivery pistons, which are connected to the or a drive piston movably mounted in a drive cylinder of the drive fluid system, preferably rigidly. Particularly preferably, it is provided that the drive piston is arranged between the two delivery pistons. A rigid connection of the drive piston with the two delivery pistons allows a synchronous lifting movement of the delivery piston and the drive piston.

In a group of embodiments of the invention can be provided that the delivery piston is designed as a plunger. Plungers, also called plungers, are characterized by a simple construction. The plunger displaces by its volume while reducing the volume of the working space, the liquid to be conveyed from the delivery cylinder. In an embodiment of the delivery piston as a plunger, a seal arranged stationarily on the delivery cylinder may be provided, wherein a relative movement of the delivery piston relative to the seal takes place during the pumping process.

In other embodiments according to the invention it is provided that the delivery piston has at least one circumferential seal. In these Embodiments is the seal, preferably stationary, arranged on the delivery piston, whereby a relative movement of the seal relative to the delivery cylinder takes place.

In the embodiments in which the delivery piston comprises a peripheral seal, it is conveniently provided that the pump assembly has two working spaces, the delivery piston separating a first of the working spaces and a second of the working spaces, and each of the working spaces having at least one inlet valve and at least one outlet valve assigned. The delivery piston thus conveniently acts double-acting, i. that one of the two working spaces for the suction of liquid through the inlet valve is increased, while the second working space is reduced at the same time for discharging liquid through the outlet valve.

The pressure evaluation unit of the wear monitoring device advantageously has a memory for storing pressure measurement values and a microprocessor for processing the pressure measurement values. The pressure evaluation unit could also be integrated in a control device of the pump arrangement.

It is preferably provided that the wear monitoring device comprises a reporting unit for informing a user in the presence of a detected by the pressure evaluation unit wear of the at least one inlet valve and / or the at least one exhaust valve. For example, the annunciator could output visual and / or audible information to the user. In addition to the output of a warning in the presence of wear of the intake valve and / or exhaust valve, it is also conceivable that continuous, in particular visual, operating data about the state of the intake valve and / or exhaust valve are output to the user.

In preferred embodiments, the pump arrangement according to the invention comprises at least one proximity switch for detecting an end position, preferably the end positions, of the delivery piston and / or the or one in one Drive cylinder of the drive fluid system movably mounted drive piston on. By providing a proximity switch, the position of the delivery piston and / or the drive piston in the monitoring of the wear of the inlet valve and / or the exhaust valve of the pressure evaluation unit in the processing of pressure readings can be taken into account.

It is particularly preferred that the pump arrangement has exactly one pressure sensor for measuring the pressure of the drive fluid, wherein the pressure sensor is arranged between a, preferably volumengeregelten, drive fluid pump and a switching valve for controlling the direction of movement of the at least one delivery piston. The drive fluid pump and the changeover valve are preferably components of the drive fluid system. Thereby, a pressure transducer for measuring the pressure of the drive fluid in a first and a second direction of movement of the drive piston and / or delivery piston can be used.

The present invention also relates to a method for monitoring the wear of at least one inlet valve and / or at least one outlet valve of a pump arrangement according to the invention.

In this case, it is preferably provided that the pressure evaluation unit forms at least one characteristic value from pressure measurements processed during a lifting operation of the delivery piston, and the characteristic values of a sequence of lifting operations are evaluated.

Particularly preferably, the pressure evaluation unit from processed pressure measured values during a stroke of the drive piston in a first direction of movement a first characteristic and from processed pressure readings of a subsequent stroke of the drive piston in a second direction of movement, which is opposite to the first direction of movement, a second characteristic value, wherein the difference Characteristic values with one in advance defined threshold value are compared.

In a preferred method it is provided that the first characteristic value is an increase value of the pressure rise during the stroke of the drive piston in the first direction of movement and the second characteristic value is an increase value of the pressure increase during the stroke of the drive piston in the second direction of movement.

In further preferred methods it could be provided that the pressure evaluation unit from processed pressure measurement values during a stroke of the drive piston forms a characteristic value which is compared with a reference value. Conveniently, the reference value is determined for intact intake valves and / or exhaust valves. The reference value could be determined, for example, during the first startup of the pump arrangement and stored in the pressure evaluation unit. The reference value could also be assigned a tolerance range. Then it could be provided that it is only then recognized that wear is present if the determined characteristic value lies outside the tolerance range surrounding the reference value.

Fig. 1

eine schematische Darstellung eines ersten Ausführungsbeispiels einer erfindungsgemäßen Pumpenanordnung;

Fig. 2

eine schematische Darstellung eines zweiten Ausführungsbeispiels gemäß der Erfindung, und

Fig. 3

eine Darstellung eines beispielhaften Druckverlaufs im Antriebsfluidsystem gemäß Fig. 1 beim Auftreten von Verschleiß bei einem der Einlassventile.

Further features and details of preferred embodiments of the invention will be explained with reference to the drawings. Show it:

Fig. 1

a schematic representation of a first embodiment of a pump assembly according to the invention;

Fig. 2

a schematic representation of a second embodiment according to the invention, and

Fig. 3

a representation of an exemplary pressure profile in the drive fluid system according to Fig. 1 when wear occurs on one of the intake valves.

In the Fig. 1 and 2 are two embodiments of pump assemblies for pumping, in particular contaminated with dirt particles, liquid shown. Such a pump arrangement could, for. B. at one Canal cleaning vehicle be arranged. In the following description, therefore, the contaminated especially with dirt particles, liquid referred to as dirty water, even if pump assemblies according to the invention, especially according to these embodiments shown here, of course, can be used for other liquids. Dirty water often has abrasive dirt particles in the form of granular and / or fibrous substances. In other embodiments, the pump assembly according to the invention could also be used for pumping other mixtures of liquid and solid materials, eg liquid concrete.

In the first embodiment according to Fig. 1 For example, the pump arrangement for pumping dirty water has two delivery cylinders 5, 6, each with a working space 1, 2. In the delivery cylinder 5, a delivery piston 3 and in the delivery cylinder 6, a delivery piston 4 is arranged to be linearly movable. The delivery piston 3, 4 are formed in this embodiment as a plunger. The sealing of the working space 1, 2 with respect to the conveyor cylinder 5, 6 and the respective delivery piston 3, 4 is effected by the respective delivery cylinder 5, 6 fixedly arranged seals 16. By a relative movement of the respective delivery piston 3, 4 relative to the respective delivery cylinder 5, the sixth is the volume of the workrooms 1, 2 changeable.

Each working chamber 1, 2 is associated with an inlet valve 7 and an outlet valve 8, respectively. The intake valves 7 and exhaust valves 8 are designed as spring-biased check valves and known per se. If the at least one inlet valve 7 and / or the at least one outlet valve 8 are intact, one of the passage directions for liquid is blocked in a closed position. In the opposite passage direction, liquid can flow through the opened inlet valve 7 and / or outlet valve 8. The valve disks of the intake valves 7 and exhaust valves 8, which are shown schematically, are thus spring-biased in the closed position against a corresponding valve seat, cf. Fig. 1 ,

The intake valves 7 are connected to a suction port 9 of the pump arrangement fluidly connected. At the suction port 9, a suction line, not shown, for receiving dirty water or in general of, in particular contaminated with dirt particles, liquid can be connected. The exhaust valves 8 are fluidly connected to an outlet port 10 of the pump assembly. From the outlet port 10 away, a line also not shown in a, for example, arranged on a sewer cleaning vehicle, storage tank for wastewater could lead.

The pump assembly includes a drive fluid system 20 operable with a drive fluid. As drive fluid, for example, hydraulic oil can be used. The drive fluid system 20 is in the embodiments shown herein as a closed system, i. the drive fluid is conveyed in a circuit in the drive fluid system 22.

The drive fluid system 20 has a volume-controlled drive fluid pump 27 which can be driven, for example, by means of an electric motor 28. Instead of an electric motor, e.g. Also, an internal combustion engine, a hydraulic motor or the like can be used. The volume-controlled drive fluid pump 27 shown here in the exemplary embodiment shown provides a constant volume flow for moving a drive piston 21, for example, preselected by the user by means of a control device 30 of the pump arrangement. The drive piston 21 is mounted linearly movable in a drive cylinder 22 of the drive fluid system 20. The drive piston 21 having a circumferential seal separates a first drive space 23 and a second drive space 24 from each other.

A switching valve 26 alternately supplies the pressurized drive fluid to the first drive space 23 or the second drive space 24, while drive fluid is discharged from the other of the two drive spaces 23, 24 and collected in an oil pan 29 of the drive fluid system 20. The drive fluid collected in the oil sump 29 can subsequently be sucked in again by the drive fluid pump 27, thus closing the circuit of the drive fluid system 20 is. The switching valve 26 of the drive fluid system 20 can be controlled by means of the control device 30 of the pump arrangement.

The pump assembly according to Fig. 1 further comprises two proximity switches 43 for detecting the end positions of the drive piston 21. The signal of the proximity switch 43 is evaluated by the control unit 30, wherein the switching valve 26 is switched on reaching an end position to reverse the direction of movement of the drive piston 21. In the embodiment according to Fig. 1 the proximity switches 43 are arranged on the delivery cylinders 5, 6. The end positions of the drive piston 21 are thus indirectly output to the control device 30 via a signal of the corresponding proximity switch 43 caused by the presence of one of the delivery pistons 3, 4 at the respective end position.

The delivery pistons 3, 4 are rigidly connected to the drive piston 21. The drive piston 21 is arranged in this embodiment between the delivery piston 3, 4. With this arrangement, it is possible to allow continuous discharge of dirty water from the side of the suction port 9 to the side of the outlet port 10.

A movement of the delivery piston 3, caused by the movement of the drive piston 21, in a first direction of movement 31 leads to an increase in the volume of the working space 1. In this case, dirty water is sucked into the working space 1 via the suction connection 9 through the inlet valve 7 assigned to the working space 1 , The valve plate of the inlet valve 7 is lifted by the negative pressure arising in the working space 1 from the valve seat, wherein liquid flows from the suction port 9 into the working space 1. The outlet valve 8 associated with the first working space 1 is in the closed position when the delivery piston 3 moves in the first direction of movement 31 and, with an intact outlet valve 8, prevents backflow of dirty water via the outlet connection 10 into the working space 1.

Simultaneously with the movement of the delivery piston 3 takes place, due to the rigid connection with the drive piston 21, and a synchronous movement of the delivery piston 4 in the first direction of movement 31, wherein the volume of the working space 2 is reduced. In this case, dirty water is expelled from the working space 2 through the outlet valve 8 assigned to the working space 2 in the direction of the outlet connection 10. The inlet valve 7 assigned to the working space 2 is in the closed position during a movement of the delivery piston 3 in the direction of movement 31 and, in the case of an intact inlet valve 7, prevents backflow of dirty water in the direction of the suction connection 9. Upon reaching a relative to the in Fig. 1 illustrated embodiment, end position, which is determined by the arranged on the delivery cylinder 6 proximity switch 43, the direction of movement of the drive piston 21 and the delivery piston 3, 4 reversed by switching the switching valve 26. During a movement of the delivery pistons 3, 4 in the second movement direction 32 directed counter to the first movement direction 31, a collection of dirty water takes place through the suction connection 9 into the working space 2 and an expulsion of dirty water from the working space 1 toward the outlet connection 10.

The first drive chamber 23 and the second drive chamber 24 are each sealed by means of a seal 16 against the, in normal operation filled with dirty water, working spaces 1, 2.

The pump arrangement has a wear monitoring device 40 for monitoring the wear of the inlet valve 7 and / or the outlet valve 8. For this purpose, a pressure sensor 41 of the wear monitoring device 40 for detecting the pressure of the drive fluid in the drive fluid system 20 is arranged. The pressure readings issued by the pressure transducer 41 are processed by a pressure evaluation unit 42. The pressure transducer 41 is disposed between the drive fluid pump 27 and the switching valve 26. Thereby, a single pressure transducer 41 for detecting the pressure of the drive fluid during the movement of the drive piston 21 in the first direction of movement 31 and the Detecting the pressure of the drive fluid in the second direction of movement 32 done. The arrangement of the pressure transducer 41 between the drive fluid pump 27 and the switching valve 26 can be dispensed with an additional pressure transducer 41. It would also be conceivable and possible in other embodiments to measure the pressure at another location in the drive fluid system 20, for. B. at the respective connecting line between the first drive chamber 23 and the switching valve 26 and the second drive chamber 24 and the switching valve 26th

The wear monitoring device 40 has a reporting unit 44 for audible and / or visual information of a user in the presence of a detected by the pressure evaluation unit 42 wear of the at least one inlet valve 7 and / or the at least one exhaust valve 8.

If wear of the at least one inlet valve 7 and / or of the at least one outlet valve 8 occurs, the reliable sealing of the valve plate relative to the valve seat in the closed position is no longer possible. This can lead to a backflow of liquid through the inlet valve 7 or the outlet valve 8, whereby the performance of the pump assembly or the flow rate per unit time is reduced. With the pressure evaluation unit 42, the wear of the at least one inlet valve 7 and / or the at least one outlet valve 8 can be monitored, since with a backflow of liquid, e.g. during the reduction of the volume of one of the working spaces 1, 2 via a worn inlet valve 7 from the affected working space 1, 2 out, and the pressure curve is influenced in the drive fluid.

In the exemplary embodiment, it is provided that, in addition to pressure readings issued by the pressure transducer 41, the signals of the proximity switches 43, which detect the end position of the delivery pistons 3, 4 or of the drive piston 21, are transmitted from the control device 30 to the pressure evaluation unit 42. As a result, an assignment of the measured pressure measured values to strokes in the first movement direction 31 and the second movement direction 32 can take place. alternative or additionally, it is also possible that the current switching state of the switching valve 26 is transmitted from the control device 30 to the pressure evaluation unit 42, in order to allow an assignment of the pressure measured values to the current direction of movement of the drive piston 21.

In Fig. 3 is an example of a pressure curve of the drive fluid, which is detected with the pressure transducer 41, shown in a diagram. The pressure at a given time is plotted on the ordinate and the corresponding time on the abscissa of the graph. The pressure curve 50 is shown in simplified form in order to clarify the principle of the processing of the pressure measurement values by the pressure evaluation unit 42.

The pressure profile 50 at the beginning of each stroke of the working piston 21 in the first and second directions of movement 31, 32 has a striking valley 57. The drawn time period 53 marks the pressure profile recorded during a stroke of the working piston 21 in the first movement direction 31, while the time interval 54 marks the pressure profile recorded during a stroke of the working piston 21 in the second movement direction 32.

On the basis of the pressure measured values processed during a sequence of strokes, a characteristic value 51, 52 is formed and the difference between the characteristic values 51, 52 of successive lifting operations is compared with a predefined threshold value. In the exemplary embodiment, the determination of average gradient lines 55, 56 of the pressure profile 50 takes place during a respective time interval 53, 54. The average gradient line 55, 56 is determined by the pressure evaluation unit 42, for example by means of a regression calculation. Extreme rashes at the beginning or end of each stroke can be disregarded. From the slope value of the slope line 55, a first characteristic 51 is formed. For the period 54, the slope value of the slope line 56 is determined as a second parameter 52.

In view of the in Fig. 3 shown pressure profile 50 it can be seen that the Characteristic 51, ie the slope of the slope line 55, in the period 53 is smaller than the characteristic 52, ie the slope of the slope line 56 in the period 54. The pressure evaluation unit 42 determines the difference of the characteristic values 51, 52 and compares this difference with the pre-defined threshold. If the difference exceeds the previously defined threshold value, warning information is sent via the reporting unit 44 to the user. In other words, in this method, a characteristic value 51 formed from the processed pressure measured values during a stroke in the first movement direction 31 is compared with a characteristic value 52 formed from the processed pressure measured values during a stroke in the second movement direction 32. From a relative deviation of the characteristic values 51 , 52 from each other can be closed to the presence of wear of the at least one inlet valve 7 and / or outlet valve 8 and, for example, via the reporting unit 44 a corresponding information to users submitted.

The characteristic values 51, 52 are determined in the exemplary embodiment from mean gradient lines 55, 56 of the pressure profile 50. It is conceivable and possible to use other characteristic values for monitoring the wear of the intake valve 7 and / or the exhaust valve 8. For example, a maximum pressure detected during a stroke could be compared to a maximum pressure of a subsequent stroke.

Alternatively or additionally, it could also be provided that the pressure evaluation unit 42 forms from processed pressure measured values during a stroke of the drive piston 21 a characteristic value which is compared with a reference value. The reference value could be determined, for example, during the first startup of the pump arrangement and stored in the pressure evaluation unit 42. As already explained above, the reference value could also be assigned a tolerance range. It could be provided in this context that only then is detected on the presence of wear or the above information about the presence of wear to the user eg via the reporting unit 44 is released when the determined characteristic value is outside the tolerance range surrounding the reference value.

In Fig. 2 a second embodiment of a pump assembly according to the invention is shown. The construction of the drive fluid system 20 of the pump arrangement corresponds to that of the first embodiment, so that in the explanations to the second embodiment mainly referred to the differences from the first embodiment. Otherwise, the explanations to the first embodiment also apply in the second embodiment. Also, with regard to the operation of the intake valves 7 and intake valves 8, reference is made to the explanations of the first embodiment.

The pump arrangement according to the second exemplary embodiment comprises a delivery piston 13, which has a peripheral seal 15 arranged stationarily on the delivery piston 13. The delivery piston 13 is mounted linearly movable in a delivery cylinder 14. The delivery piston 18 is rigidly connected to the drive piston 21 by means of a piston rod 18. The pump assembly has two working spaces 11, 12, wherein the delivery piston 13 separates the first of the working spaces 11 and the second of the work spaces 12 from each other. Each of the working spaces 11, 12 is associated with an inlet valve 7 and an outlet valve 8.

During a movement of the delivery piston 13 in the direction of movement 31, a reduction of the working space 11, while at the same time an increase in the volume of the working space 12 takes place. The seal 17 separates the second working space 12 and the second drive space 24 of the drive cylinder 22 from each other. The movement of the drive piston 21 is analogous to the first embodiment, wherein the end position of the drive piston 21 takes place directly over the arranged on the drive cylinder 22 proximity switch 43.

In the embodiment according to Fig. 2 the first drive space 23 has a circular cylindrical shape. The second drive space 24 has due to the drive space 24 inwardly bounding piston rod 18 a annular cylindrical shape. When operating with a volume-controlled drive fluid pump 27, which provides a constant volume flow for moving the drive piston 21, therefore takes place in the second embodiment, the lifting movement in the first direction of movement 31 slower than in the second direction of movement 32. That is, for a lifting movement in the first direction of movement 31 is a This can be taken into account by the pressure evaluation unit 42 during the processing of the pressure measurement values output by the pressure transducer 41. So z. B. in the determination of characteristic characteristics 51, 52, a correction value, which maps the design of the different shape of the drive working chambers 23, 24, are included by the pressure evaluation unit 42 for taking into account the different time periods 53, 54 in the monitoring of wear. Otherwise, the monitoring of the wear of the at least one inlet valve 7 and / or outlet valve 8 by means of the wear monitoring device 40 can be carried out analogously to the first embodiment. Legend to the reference numbers: 1 working space 29 oil pan 2 working space 30 control device 3 delivery piston 31 first direction of movement 4 delivery piston 32 second direction of movement 5 delivery cylinders 6 delivery cylinders 40 Wear monitoring device 7 intake valve 8th outlet valve 41 Pressure transducer 9 suction 42 Druckauswerteeinheit 10 outlet 43 proximity switch 11 working space 44 reporting unit 12 working space 13 delivery piston 50 pressure curve 14 delivery cylinders 51 characteristic value 15 poetry 52 characteristic value 16 poetry 53 Period of time 17 poetry 54 Period of time 18 piston rod 55 slope line 56 slope line 20 Driving fluid system 57 valley 21 drive piston 22 drive cylinder 23 first drive space 24 second drive space 25 poetry 26 switching valve 27 Drive fluid pump 28 engine

Claims (10)

Pump arrangement for pumping a, in particular contaminated with dirt particles, liquid, the pump assembly at least one working space (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), for sucking liquid through the inlet valve (7) into the working space (1, 2, 11, 12) and for discharging liquid through the outlet valve (8) through the working space (1, 2, 11, 12), and the pump assembly comprises a wear monitoring device (40) for monitoring the wear of the inlet valve (7) and / or outlet valve (8) with at least one pressure sensor (41) and a Pressure evaluation unit (42) for processing of the pressure transducer (41) output pressure readings, characterized in that the pump arrangement for moving the delivery piston (3, 4, 13) operable with a drive fluid s drive fluid system (20), and the pressure transducer (41) of the wear monitoring device (40) for detecting the pressure of the drive fluid in the drive fluid system (20) is arranged. Pump arrangement according to claim 1, characterized in that in a drive cylinder (22) of the drive fluid system (20) a drive piston (21) is movably mounted, which is mechanically coupled to the at least one delivery piston (3, 4, 13). Pump arrangement according to claim 1 or 2, characterized in that the pump arrangement comprises two delivery pistons (3, 4), which are connected to the or one, in a drive cylinder (22) of the drive fluid system (20) movably mounted drive piston (21), preferably rigid are. Pump arrangement according to one of claims 1 to 3, characterized in that the delivery piston (3, 4) is designed as a plunger. Pump arrangement according to one of claims 1 to 4, characterized in that the delivery piston (13) has at least one circumferential seal (15). Pump arrangement according to Claim 5, characterized in that the pump arrangement has two working spaces (11, 12), the delivery piston (13) separating a first of the working spaces (11) and a second of the working spaces (12), each of the working spaces (11 , 12) at least one inlet valve (7) and at least one outlet valve (8) is associated. Pump arrangement according to one of claims 1 to 6, characterized in that the wear monitoring device (40) has a reporting unit (44) for informing a user in the presence of a detected by the pressure evaluation unit (42) wear of the at least one inlet valve (7) and / or the at least an exhaust valve (8). Pump arrangement according to one of claims 1 to 7, characterized in that the pump arrangement at least one proximity switch (43) for detecting an end position of the delivery piston (3, 4, 13) and / or or in a drive cylinder (22) of the drive fluid system (20 ) movably mounted drive piston (21). Pump arrangement according to one of claims 1 to 8, characterized in that the pump arrangement has exactly one pressure transducer (41) for measuring the pressure of the drive fluid, wherein the pressure transducer (41) between one, preferably Volumengeregelten, drive fluid pump (27) and a switching valve (26) for controlling the direction of movement of the at least one delivery piston (3, 4, 13) is arranged. Method for monitoring the wear of at least one inlet valve (7) and / or at least one outlet valve (8) in a pump arrangement according to one of claims 1 to 9, wherein the pressure evaluation unit (42) respectively during a lifting operation of the delivery piston (3, 4, 13), at least one characteristic value (51, 52) is processed, and the characteristic values (51, 52) of a sequence of lifting processes are evaluated.

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