EP3207255A1

EP3207255A1 - Fluid pump

Info

Publication number: EP3207255A1
Application number: EP14783651.4A
Authority: EP
Inventors: Jörg SCHMID
Original assignee: Alfred Kaercher SE and Co KG
Current assignee: Alfred Kaercher SE and Co KG
Priority date: 2014-10-13
Filing date: 2014-10-13
Publication date: 2017-08-23
Also published as: WO2016058628A1; CN106795887A

Abstract

The invention relates to a fluid pump (10) having a pump chamber (28), which is connected to a pump inlet (32) by way of an inlet line (30) and to a pump outlet (36) by way of an outlet line (34), and in which a pump member (22) than can be actuated by a motor (18) is arranged, and having a control device (24) for controlling the motor (18) in dependence of the position of a valve body (66) of a control valve (42) that is movably held in the inlet line (30). In order to refine the fluid pump such that the fluid pump allows a control of the motor (18) that is less susceptible to malfunction as a function of the position of the valve body (66), the fluid pump (10) according to the invention has an elastically expandable expansion volume, which is connected to the pump member (22).

Description

LIQUID PUMP

The invention relates to a fluid pump with a pump chamber, which is connected via an inlet line to a pump inlet and via an outlet to a pump outlet and in which a motor driven by a pump member is arranged, and with a control device for controlling the motor in dependence on the position a valve body movably held in the inlet pipe of a control valve.

Liquid pumps with a motor and a pump element driven by the motor are known in various designs. They are used for example in high-pressure cleaning equipment and for example in the household and / or in the garden, with their help rainwater from a collection point, such as a pond or a rainwater tank, can be promoted to a connected to the pump outlet of the liquid pump liquid delivery member. As a liquid delivery device, for example, a faucet, a spray nozzle or a spray gun can be used. For the proper dispensing of liquid, the user can optionally open and close the liquid delivery member.

From DE 199 23 357 AI a liquid pump is known, wherein for controlling the motor, a control device is used with a arranged in the outlet check valve and a downstream of the check valve arranged pressure switch. The check valve has a movably mounted valve body whose position is detected by means of a sensor. Closes the user after a successful liquid delivery connected to the liquid pump liquid discharge member, then the motor of the liquid pump is switched off by the pressure switch. If the user releases the liquid discharge at a later point in time, the valve body lifts off from a valve seat and the The sensor detecting the valve body provides a sensor signal, under the action of the motor is turned on again.

It has also been proposed to arrange a control valve with a movably mounted valve body in the inlet line of the liquid pump, wherein the motor can be switched on and off in dependence on the position of the valve body.

However, the control of the engine depending on the position of the valve body can lead to difficulties when the liquid pump is connected to a rigid piping system, as it is not ensured in all cases that the valve body reliably at a stop of the liquid discharge a position for switching off the Motor occupies and maintains. Rather, it may be the case that the valve body performs an oscillating movement between a position in which the engine is turned off and a position in which the engine is turned on again. This can lead to a malfunction of the liquid pump. Such interference can also occur when a check valve is connected to the pump outlet.

Object of the present invention is to provide a liquid pump of the type mentioned in such a way that it allows a störungsunempfindlichere control of the motor in response to the position of the valve body of the control valve.

This object is achieved in a liquid pump of the generic type according to the invention that the liquid pump has an elastically expandable expansion volume, which is connected to the pumping member.

If the liquid delivery is interrupted in the liquid pump according to the invention by a liquid discharge member connected to the liquid pump is closed, this has the consequence that with The expansion volume of the liquid pump connected to the pumping member expands counter to the effect of an elastic restoring force, since the engine is initially still in operation and drives the pumping member. The elastically expansible expansion volume forms an accumulator. Since the valve body is no longer flowed around by the liquid due to the interrupted liquid discharge, it can first assume a rest position in which the engine is switched off. With the switching off of the motor eliminates the conveying effect of the pumping member and the expansion volume contracts due to the applied elastic restoring force, escaping from the expansion volume liquid. The liquid escaping from the expansion volume reliably and permanently pushes the valve body into a closed position, in which the engine remains switched off and the fluid pump can assume a standby state. When the liquid dispensing is released by the user, in which the liquid discharge member is reopened, the pressure of the liquid downstream of the valve body decreases and the valve body is moved in the flow direction of the liquid, and due to this position change, the motor can be switched on again by the control device.

The provision of the elastically expansible expansion volume integrated into the fluid pump thus ensures that the valve body of the control valve reliably assumes a position in which the engine remains switched off after an interruption of the fluid delivery. Repeated starting and stopping of the engine is reliably avoided by providing the expansion volume even if the fluid pump is connected to a rigid piping system or if a check valve is connected to the pump outlet. For the function of the liquid pump, it is therefore not absolutely necessary to connect an elastically expandable hose or a separate, elastically expandable pressure compensation vessel to the pump outlet. Rather, with the liquid pump, an elastically expandable expansion volume is provided, which allows reliable control of the engine. Maintenance-intensive additional external components are thus required for the operation of the liquid pump not required. This facilitates their handling, so that the liquid pump can be used by technically inexperienced users in a simple manner.

It can be provided that the elastically expandable expansion volume is integrated into the pump chamber.

In an advantageous embodiment of the invention, the liquid pump has an elastically expandable expansion chamber, which is connected to the pump space and defines the expansion volume.

It can be provided, for example, that the liquid pump has a pumping chamber which defines the pumping space and which is connected to the expansion chamber.

The connection between the pumping chamber and the expansion chamber advantageously takes place via a connecting line.

However, it can also be provided that the expansion chamber directly adjoins the pumping chamber. For example, the pumping chamber may have an opening to which the expansion chamber immediately adjoins.

Advantageously, the expansion chamber is arranged on the outside of the pumping chamber, because this allows the liquid pump to have a compact design.

It is advantageous if the liquid pump has an outer housing which surrounds the pumping member and the expansion volume. In particular, the outer housing may surround the pumping chamber and the expansion chamber. The expansion volume is thus not directly accessible to the user of the liquid pump. An incorrect operation of the liquid pump can be avoided. In addition, the arrangement of the pumping limb and the expansion volume in a common outer housing has the advantage that the liquid pump has a very compact design.

In a particularly preferred embodiment, the liquid pump according to the invention comprises a chamber housing, in which the expansion chamber is arranged, wherein the chamber housing a counter to the action of an elastic restoring force movable intermediate wall, which forms a wall portion of the expansion chamber. In an interruption of the liquid discharge, the expansion chamber expands by the arranged in the chamber housing intermediate wall moves against the action of an elastic restoring force. If the motor of the liquid pump is switched off after liquid dispensing, so the expansion chamber can contract again by the intermediate wall moves back under the action of the elastic restoring force back to its original position. In this case, liquid can flow from the expansion chamber back into the pump chamber and reliably press the valve body held movably in the inlet line in a closed position, wherein the positioning of the valve body in the closed position has the consequence that the engine remains switched off.

The force acting on the intermediate wall of the chamber housing elastic restoring force can be provided for example by a return spring. For this purpose, it can be provided that the intermediate wall can be acted upon by a return spring with the restoring force.

As a return spring, for example, a compression spring can be used, which is clamped between a spring holder and the intermediate wall.

The pen holder is conveniently fixed to the chamber housing.

The intermediate wall is preferably designed as a piston, which is mounted displaceably in the chamber housing and by means of a sealing element, preferably a sealing ring, on an inner side of the chamber housing flüssigkeitss- tight. The designed as a piston intermediate wall can be moved back and forth within the chamber housing, so that the volume of the expansion chamber can increase and decrease in dependence on the pressure prevailing in the pump chamber of the liquid. In an interruption of the liquid delivery, the expansion chamber can first absorb liquid, thereby increasing its volume. The liquid can then be discharged back to the pumping space and the downstream of the control valve portion of the inlet conduit, wherein the volume of the expansion chamber decreases again.

The intermediate wall divides the chamber housing in a particularly preferred embodiment of the invention in the expansion chamber and in a compensation chamber, wherein the compensation chamber is connected to a arranged upstream of the control valve portion of the inlet conduit. The chamber housing is thus connected on the one hand to the pump chamber and on the other hand to a section of the inlet line arranged upstream of the control valve.

Preferably, the volumes of the expansion chamber and the compensation chamber are alternately changeable. When interrupting the liquid discharge, the volume of the expansion chamber can first be increased and at the same time the volume of the compensation chamber can be reduced. Liquid can pass from the pump room into the expansion chamber. After switching off the engine, the liquid from the expansion chamber can flow back into the pump chamber, wherein the volume of the expansion chamber decreases and increases the volume of the compensation chamber. Increasing the volume of the compensation chamber after switching off the engine while reducing the volume of the expansion chamber has the advantage that liquid from the upstream of the control valve portion of the inlet conduit liquid can flow into the compensation chamber, when arranged in the inlet line valve body under the action of From the expansion chamber flowing out liquid is pressed into its closed position. The movement of the valve body in its closed position is thus not affected by the liquid located upstream of the valve body. The movement of the valve body and thus also dependent on the position of the valve body control of the motor is thus ensured even if a check valve is arranged at the pump inlet, which prevents outflow of liquid through the pump inlet from the liquid pump out. The provision of a compensation chamber in addition to the expansion chamber thus enables trouble-free operation of the liquid pump even if a check valve is arranged at the pump inlet and at the pump outlet and the liquid pump is connected to a rigid piping system.

The chamber housing is preferably arranged on the outside of the inlet line.

The arranged in the inlet line control valve has in an advantageous embodiment of the liquid pump according to the invention on a closing area and a release area, wherein a flow connection from the pump inlet to the pump chamber in a positioning of the valve body in

Closing area is interrupted and released in a positioning of the valve body in the release area, wherein the valve body is movable within the closing area in response to the force acting on the valve body pressure of the liquid against the action of one or more return elements, and wherein the valve body within the release area in dependence the flow rate of the fluid flowing through the control valve is movable counter to the action of one or more return elements. In such an embodiment, the control valve has both the function of a check valve and the function of a flow and a pressure sensor. The valve body of the control valve can move in a closing area and in a release area. If it is in the closing area, it interrupts the flow connection between the pump inlet and the pump chamber. The closing area extends as well as the release area in the longitudinal direction of the inlet channel. The position occupied by the valve body within the closing area is dependent on which pressure acts on the valve body. It is the pressure of the fluid downstream of the valve body. If the valve body is in the release area, it releases the flow connection between the pump inlet and the pump space. The position occupied by the valve body within the release region is dependent on the flow rate of the liquid flowing through the inlet channel. At a low flow rate, the valve body occupies a position within the release area at a closer distance to the closing area, and at a larger flow rate, the valve body within the release area occupies a position at a greater distance from the closing area.

The control of the engine by means of a control device. If liquid is dispensed by the liquid pump, the valve body is moved by the liquid flowing through the inlet channel against the action of at least one restoring element within the release region into a release position spaced from the closing region. If the liquid dispensing is stopped by a user, then the valve body is no longer flowed around by liquid. This has the consequence that the valve body moves under the action of at least one restoring element in the direction of the closing area in a rest position. The reaching of the rest position can be detected by a sensor device and then the motor can be switched off after a short delay time. With a low liquid flow, the pressure of the liquid increases in the pump chamber and in the expansion volume connected to the pump chamber, so that the expansion volume expands elastically. The subsequent shutdown of the motor has the consequence that the pressurized fluid moves the valve body within the closing area against the action of at least one return element in the direction away from the release area direction, so that the valve body reliably assumes a closed position, at the same time the expansion volume decreases again , The reaching of a predetermined closed position can be detected by the sensor device. If the user releases the liquid at a later time, the pressure acting on the valve body decreases and the valve body becomes smaller moved by at least one return element from the predetermined closed position in the direction release area. Leaving the closed position can also be detected by the sensor device and then the motor of the liquid pump can be turned on again.

In contrast to known non-return valves, in which the valve body rests immovably against a rigid valve seat when the valve is closed, the valve body of the advantageous control valve can move within the closing range in the event of an interrupted flow connection between the pump inlet and the pump chamber as a function of the pressure acting on the valve body. This makes it possible to provide a control signal for switching on the motor of the liquid pump by means of the sensor device when the pressure acting on the valve body drops and the valve body moves within the closing area in the direction of the release area. In a corresponding manner, a sensor signal for switching off the pump can be provided by the sensor device when the liquid flow in the inlet line is omitted and the valve body, after having previously assumed a position in the release area, is moved in the direction of the closing area. Slight variations in the flow rate or pressure of the liquid will not affect control of the liquid pump as well as the presence of air bubbles in the liquid.

In an advantageous embodiment, the control valve has a valve housing which forms a flow channel which extends from a channel inlet to a channel outlet and in which the valve body is movably arranged to release and interrupt the flow connection between the channel inlet and the channel outlet. The valve housing is arranged liquid-tight in the inlet line and is flowed through during operation of the liquid pump from the liquid. In the flow passage of the valve body is movably supported, wherein the flow channel forms a closing area and a release area. It is advantageous if the valve body rests in the closing area in a liquid-tight manner on a channel wall of the flow channel. The tight fit of the valve body to the duct wall results in a reliable interruption of the flow communication between the duct inlet and the duct outlet.

It may, for example, be provided that the valve body has a sealing element, for example an O-ring or a sealing lip, wherein the sealing element slides along the channel wall during a movement of the valve body within the closing area.

The valve body is conveniently held displaceably in the flow direction of the liquid.

It is advantageous if the flow channel is designed in a straight line and the valve body is held linearly displaceable within the flow channel.

The closing region of the flow channel is designed cylindrically in an advantageous embodiment or it widens in the flow direction of the liquid.

In particular, a conical configuration of the closing area has proven to be advantageous. A conical configuration of the closing area has the advantage that the pressing force acting on the sealing element within the closing area increases progressively the farther the valve body moves from the clearance area into the closing area. This leads to an increasing sealing effect. In particular, in a predetermined closed position, which takes the valve body under pressure when the pump is switched off, a very high sealing effect can be achieved. The cone angle of the closing area is preferably less than 5 °, in particular less than 1 °, for example 0.6 °. It is advantageous if the diameter of the flow channel widens suddenly in the release area. In such an embodiment, the release area has a first partial area with a smaller diameter that adjoins the closing area and an adjoining second partial area with a larger diameter.

If the valve body assumes a position in the first subregion, then the flow rate of the liquid is advantageously at most 60 l / h.

If the valve body assumes a position in the second partial region, the flow rate of the liquid is advantageously more than 60 l / h.

Preferably, the valve body in the first portion of a sensor device can be detected. This gives the possibility to turn off the engine of the liquid pump, if the valve body is longer than a predetermined time interval with the engine in the first sub-range, because a longer stay of the valve body in the first sub-range with the engine running and thus with active fluid pump indicates a lack of flow around the valve body with liquid, in particular to a lack of liquid, so that there is a risk of damage to the liquid pump. The residence time of the valve body in the first portion of the release area is therefore detectable in an advantageous embodiment of the liquid pump according to the invention and when a predetermined maximum length of stay is exceeded when the engine is switched off, the motor can be conveniently switched off by means of the control device.

It is advantageous if the liquid pump has a sensor device and the valve body can be detected by means of the sensor device in at least two positions within the flow channel. For example, it may be provided that the valve body is detectable on the one hand in a position which it occupies when closing the liquid delivery device connected to the liquid pump when the engine is switched on, and when it is angry another can be detected in a position which he occupies after closing the liquid delivery device with the engine off.

Conveniently, by means of the sensor device, a positioning of the valve body in a predetermined rest position from a positioning of the valve body in a closed position arranged upstream of the rest position distinguishable. From the sensor device can thus be reliably distinguished whether the valve body is in its rest position or in a closed position disposed upstream of the rest position.

Alternatively or additionally, it may be provided that by means of the sensor device, a positioning of the valve body in a predetermined rest position of a positioning of the valve body in a downstream of the rest position arranged release position is distinguishable.

In an advantageous embodiment of the liquid pump according to the invention, the sensor device has at least two sensor elements, which are arranged in the flow direction of the liquid at a distance from each other. At least one of the flow elements can be designed, for example, as a reed contact or, for example, also as a magnetic-field-sensitive sensor, in particular as a Hall sensor.

It is favorable if the sensor elements have non-overlapping detection regions for detecting the valve body. If the valve body is located in one of the detection areas, it is reliably detected by one of the sensor elements. Since the detection areas do not overlap one another, the position of the valve body can be determined particularly easily, since in each case only one of the sensor elements provides a corresponding sensor signal.

It is particularly advantageous if the time sequence of the sensor signals provided by the sensor elements can be determined by means of the control device. The determination of the chronological order of the sensor signals makes it possible to detect the direction of movement of the valve body. This gives the possibility to control the motor of the liquid pump in dependence on the direction of movement of the valve body.

The following description of an advantageous embodiment of the invention is used in conjunction with the drawings for further explanation. Show it :

Figure 1: a perspective view of a liquid pump according to the invention;

Figure 2 is a perspective, partially separated partial representation of the liquid pump of Figure 1;

FIG. 3 shows a further perspective, partially separated partial representation of the liquid pump from FIG. 1;

Figure 4 is a schematic partial longitudinal sectional view of the liquid pump

FIG. 1 with a control valve arranged in an inlet line;

Figure 5: a schematic sectional view of the liquid pump along the

Line 5-5 in Figure 4;

Figure 6 is a schematic sectional view of the control valve and a chamber housing, wherein a valve body of the control valve assumes a release position and an elastically expandable expansion volume is minimal;

Figure 7 is a schematic sectional view corresponding to Figure 6, wherein the

Valve body occupies a rest position and the elastically expansible expansion volume is maximum; FIG. 8 shows a schematic sectional view corresponding to FIG. 6, wherein the valve body assumes a closed position and the elastically expansible expansion volume is minimal.

In the drawing, an advantageous embodiment of a liquid pump according to the invention in the form of a garden pump is shown schematically. The garden pump is generally occupied by the reference numeral 10. It comprises an outer housing 12, which is formed by a first housing half shell 14 and a second Gehäusehaibschalte 16. The two Gehäusehalbschalten 14, 16 take between them an electric motor 18 and connected to the electric motor 18 pumping chamber 20, in which a pumping member in the form of an impeller 22 is rotatably mounted. The impeller 22 may be rotated by the electric motor 18 to promote fluid.

For controlling the electric motor 18, the garden pump 10 has a control device 24 and a main switch 26.

The pumping chamber 20 defines a pumping space 28 which is in fluid communication with a pump inlet 32 via an inlet conduit 30 and with a pump outlet 36 via an outlet conduit 34. At the pump inlet 32, a supply line can be connected in a conventional manner, via which the garden pump 10 can be supplied with liquid. At the pump outlet 36, a discharge line can be connected in a conventional manner, the end facing away from the garden pump 10 carries a liquid discharge member, via which the funded by the garden pump 10 liquid can be dispensed. The fluid delivery device may be selectively opened and closed by the user to control fluid delivery. Such liquid delivery organs are known in the art and therefore require no further explanation in the present case.

The inlet line 30 has a filling opening 38 which can be closed by a screw cap 40. Via the filling opening 38, the pumping space 28 can be filled with liquid during commissioning of the garden pump 10. Within the inlet line 30, a control valve 42 and a filter element 44 are arranged, wherein the filter element 44 is arranged upstream of the control valve 42 in a first line section 46 of the inlet line 30. The first line section 46 extends from the filling opening 38 to a radially inwardly directed step 48, to which a second line section 50 of the inlet line 30 connects. The second conduit section 50 extends from the step 48 to a bottom 52 of the inlet conduit 30.

The control valve 42 has a valve housing 54, which forms a flow channel 56. The flow channel 56 has a channel inlet 58 disposed upstream of the step 48, and a channel outlet 60 disposed adjacent the bottom 52 and having two diametrically opposed outlet ports 62, 64.

In the flow channel 56, a valve body 66 is slidably mounted in the longitudinal direction of the flow channel 56. The valve body 66 carries a sealing ring 68. In a closing region 70, which extends from a region of the flow channel 56 at the level of the step 48 to a channel extension 72 of the flow channel 56, the sealing ring 68 is liquid-tight against the wall of the valve housing 54. Adjoining the closing region 70, via the channel widening 72, is a release region 74 of the flow channel 56. Within the release region 74, the sealing ring 68 takes a distance from the wall of the valve housing 54. The release area 74 extends to the channel outlet 60.

At the level of the stage 48, a guide member 76 is arranged in the valve housing 54, which has a passage 78. The passage 78 forms a guide for a guide tappet 80, which passes through the passage 78 and carries the valve body 66 at its end facing away from the filter element 44. At its end facing the filter element 44, the guide tappet 80 has a plate-shaped spring holder 82. Between the spring holder 82 and the guide A first return element is clamped in the form of a first return spring 84, which surrounds the guide tappet 80.

The valve body 66 is bell-shaped, and between the valve body 66 and the guide member 76, a second return element in the form of a second return spring 86 is clamped.

The valve housing 54 is supported via a sealing element in the form of an O-ring 88 on the stage 48 of the inlet line 30 and is held in a liquid-tight manner in the inlet line 30 via the O-ring 88.

As is clear from FIGS. 5 to 8, the valve body 66 carries on its outer side a permanent magnet 90. The permanent magnet 90 is assigned a sensor device 92, which is arranged at the level of the closing region 70 on the outside of the pumping chamber 20.

The sensor device 92 comprises a first magnetic field-sensitive sensor element 94, which is arranged upstream of the channel extension 72, and a second magnetic field-sensitive sensor element 96, which is arranged approximately at the level of the channel extension 72.

The flow channel 56 is configured conically in the closing region 70, wherein it widens with increasing distance from the channel inlet 58. This has the consequence that the sealing ring 68 is subject to an increasing, radially inwardly directed pressing force, the further the valve body 66 moves in the direction away from the release region 74 - in FIGS. 4 to 8, ie, upwards. The increasing pressing force increases the sealing effect of the sealing ring 68, which has a sealing lip on its outer side.

The release region 74 has a first subregion 98, which directly adjoins the channel widening 72 in the flow direction of the liquid and extends to the edge of the outlet openings 62, 64. In the area of the outlet openings 62, 64, the release area 74 forms a second partial region 100, which has a larger flow cross section than the first partial region 98 due to the outlet openings 62, 64. The flow cross section of the release region 74 thus changes abruptly during the transition from the first partial region 98 to the second partial region 100.

The two sensor elements 94, 96 are electrically connected to the control device 24 via a sensor line 102.

The valve body 66 is within the flow passage 56 in the axial direction reciprocally movable in response to the forming within the flow channel 56 pressure and flow conditions. It breaks the flow connection between the channel inlet 58 and the channel outlet 60 when it is within the closure area 70 and releases the flow communication between the channel inlet 58 and the channel outlet 60 when it is within the release area 74.

If the valve body 66 assumes a closed position adjacent to the first sensor element 94, as shown in FIG. 8, then it is located in the detection area of the first sensor element 94 and is detected by it. In the closed position, the valve body 66 completely interrupts the flow connection between the channel inlet 58 and the channel outlet 60.

If the valve body 66 assumes a rest position adjacent to the second sensor element 96, as shown in FIG. 7, then it is located in FIG

Detection area of the second sensor element 96 and is detected by this. In the rest position, the valve body 66 can be flowed around by the liquid at a flow rate of a maximum of 60 l / h.

The two sensor elements 94, 96 are arranged at such a distance from each other that their detection areas do not overlap.

If the valve body 66 is located in the second subregion 100 of the release region 74, then it takes a clear distance from the first sensor element 94 and the second sensor element 96 and can not be detected by the two sensor elements 94, 96. If neither a sensor signal is provided by the first sensor element 94 nor by the second sensor element 96, this suggests that the valve body 66 assumes a release position in the second subregion 100, as illustrated in FIG. This release position assumes the valve body 66 when the electric motor 18 is turned on and liquid is discharged under the action of the impeller 22 of the garden pump 10 via the pump outlet 36. In this case, the flow channel 56 is traversed by liquid, under the action of the valve body 66 is moved against the spring force of the first return spring 84 in the channel outlet 60 facing direction.

On the outside of the inlet conduit 30, a chamber housing 104 is arranged, which, like the pumping chamber 20 and the electric motor 18 from

Outer housing 12 is surrounded. The chamber housing 104 is substantially cylindrical in shape and is divided by an in the chamber housing 104 movably held piston 106 in an expansion chamber 108 and a compensation chamber 110. The piston 106 carries a sealing element, in the illustrated embodiment, a sealing ring 107 which bears against the inside of the chamber housing 104 liquid-tight. Within the compensation chamber 110, a return spring in the form of a compression spring 112 is arranged, which is supported on the one hand on the piston 106 and on the other hand on a chamber housing 104 on the top closing plug 114, which forms a spring holder for the compression spring 112. The expansion chamber 108 is arranged on the side of the piston 106 facing away from the pressure spring 112 and is in fluid communication with the pumping chamber 20 via a first connecting line 116. This becomes clear in particular from FIG. The compensation chamber 110 is in fluid communication with the first line section 46 of the inlet line 30 arranged upstream of the valve body 66 via a second connecting line 118. This becomes clear in particular from FIGS. 2, 6, 7 and 8. The expansion chamber 108 defines an expansion volume which is elastically expandable against the force of the compression spring 112 and which is connected via the first connection line 116 to the pumping space 28 which is arranged in the pumping chamber 20.

As already mentioned, the valve body 66 assumes its release position shown in Figure 6 when the electric motor 18 is turned on. In this state, the expansion chamber 108 has a minimum expansion volume, since the piston 106 is pressed by the compression spring 112 in this state against a housing bottom 120 of the chamber housing 104.

When the liquid dispensing is stopped by the user by closing the liquid dispenser connected to the pump outlet 36 via a dispensing line, the fluid flow within the flow channel 56 is eliminated and the valve body 66 is moved by the first return spring 84 into and out of the detection area of the second sensor element 96 detected. After a short delay time, which may be 5 seconds, for example, then the electric motor 18 is turned off by the controller 24. At low liquid flow, a liquid pressure builds up in the expansion chamber 108 connected to the pumping chamber 20 via the first connecting line 116, whereby the expansion volume widens against the force of the compression spring 112. This is shown schematically in FIG. If the electric motor 18 is now switched off after expiration of the delay time, the liquid contained in the expansion chamber 108 is pressed by the pressure spring 112 via the first connecting line 116 into the pumping space 28, so that the expansion volume decreases again and the valve body 66 moves out of its in FIG 7 shown rest position is pressed in its closed position shown in Figure 8. In this closed position, the valve body 66 is detected by the first sensor element 94. The garden pump 10 is now in a stable standby state. Liquid, which is located at the transition of the valve body 66 from its rest position in its closed position upstream of the valve body 66, via the second connecting line 118 in the Ausgleichskam- mer 110, the volume of which increases to the same extent as the expansion volume of the expansion chamber 108 decreases. The volumes of the expansion chamber 108 and the compensation chamber 110 can thus be alternately increased and decreased to ensure that the valve body 66 reliably assumes its closed position when the user interrupts the dispensing of liquid.

When the liquid dispensing is released by the user again by opening the liquid dispensing member, the pressure drops downstream of the valve body 66, and under the action of the second return spring 86, the valve body 66 is moved out of the detection area of the first sensor element 94 toward the release area 74. The first sensor signal provided by the first sensor element 94 thereby drops and due to this signal drop, the electric motor 18 is switched on again by the control device 24. The impeller 22 is thereby rotated again and the valve body 66 is moved by the liquid flowing around it again in the release position. Here, the valve body 66 moves briefly through the detection range of the second sensor element 96, so that it is briefly detected by the second sensor element 96 and the second sensor element 96 provides a short-term, pulse-like sensor signal. This short-term sensor signal has no change in the operation of the electric motor 18 result. Rather, the control device 24 detects from the chronological order of the sensor signals of the sensor elements 94 and 96, the direction of movement of the valve body 66 which moves in the present case after switching on the electric motor 18 properly from its closed position to its release position.

The garden pump 10 can be connected to a rigid piping system without affecting the control of the operation of the electric motor 18 as a function of the position of the valve body 66. This is ensured by the provision of the elastically expandable expansion volume, which makes it possible to reliably hold the valve body 66 in its closed position after the electric motor 18 has been switched off. The Control of the electric motor 18 as a function of the position of the valve body 66 is also not affected when a check valve is connected to the pump outlet 36. Also in this case, it is ensured by the elastically expandable expansion volume, that the valve body 66 reliably maintains its closed position after switching off the electric motor 18.

The control of the electric motor 18 in response to the position of the valve body 66 is not affected by the connection of a check valve to the pump inlet 32. Such check valves can be used, for example, to prevent a backflow of liquid from the pump chamber 28 into a water supply system to which the pump inlet 32 is connected. If the electric motor 18 is switched off by the control device 24, the valve body 66 can reliably assume its closed position even if an external check valve connected to the pump inlet 32 assumes its closed position, since liquid which flows when the valve body 66 passes into its closed position upstream of the Valve body 66 is located, can be absorbed by the compensation chamber 110, the volume increases in the transition of the valve body 66 in its closed position. The garden pump 10 is thus distinguished by a failure-susceptible control of the electric motor 18 as a function of the position of the valve body 66 arranged in the inlet line 30.

Claims

PATENT APPLICATIONS

A fluid pump having a pump chamber (28) which is connected via an inlet line (30) to a pump inlet (32) and via an outlet line (34) to a pump outlet (36) and in which a by a motor (18) drivable pumping member (22) is arranged, and with a control device (24) for controlling the motor (18) in dependence on the position of a in the inlet line (30) movably held valve body (66) of a control valve (42), characterized in that the liquid pump (10) has an elastically expandable expansion volume connected to the pumping member (22).

2. Liquid pump according to claim 1, characterized in that the liquid pump (10) has an elastically expandable expansion chamber (108) which is connected to the pump chamber (28) and defines the expansion volume.

3. Liquid pump according to claim 2, characterized in that the liquid pump (10) has a pumping chamber (20) which defines the pumping space (28) and which is connected to the expansion chamber (108).

4. Liquid pump according to claim 3, characterized in that the pumping chamber (20) via a connecting line (116) with the expansion chamber (108) is connected.

5. Liquid pump according to one of the preceding claims, characterized in that the liquid pump (10) has an outer housing (12) surrounding the pumping member (22) and the expansion volume.

6. Liquid pump according to one of the preceding claims, characterized in that the liquid pump (10) has a chamber housing (104) in which the expansion chamber (108) is arranged, wherein the chamber housing (104) movable against the action of an elastic restoring force movable partition having a wall portion of the expansion chamber (108) is formed.

7. Liquid pump according to claim 6, characterized in that the intermediate wall of a return spring (112) can be acted upon by the restoring force.

8. Liquid pump according to claim 6 or 7, characterized in that the intermediate wall is designed as a piston (106) which is displaceably mounted in the chamber housing (104) and by means of a sealing element (107) against an inside of the chamber housing (104) liquid-tight.

The fluid pump according to any one of claims 6 to 8, characterized in that the intermediate wall divides the chamber housing (104) into an expansion chamber (108) and a compensation chamber (110), the compensation chamber (110) being connected to an upstream of the control valve (42). arranged portion (46) of the inlet duct (30) is connected.

10. Liquid pump according to claim 9, characterized in that the volumes of the compensation chamber (110) and the expansion chamber (108) are alternately changeable.

11. Liquid pump according to one of claims 6 to 10, characterized in that the chamber housing (104) on the outside of the inlet conduit (30) is arranged.

12. Liquid pump according to one of the preceding claims, characterized in that the control valve (42) has a closing region (70) and a release region (74), wherein a flow connection from the pump inlet (32) to the pump chamber (28) during a positioning of the valve body ( 66) in the closing area (70) is interrupted and released when positioning the valve body (66) in the release area (74), wherein the valve body (66) within the closing area (70) in dependence on the pressure acting on the valve body (66) pressure of Fluid against the action of one or more return elements (86) is movable, and wherein the valve body (66) within the release region (74) in response to the flow rate of the inlet line (30) flowing liquid against the action of one or more return elements (84) is movable.

13. A liquid pump according to one of the preceding claims, characterized in that the control valve (42) has a valve housing (54) which forms a flow channel (56) extending from a channel inlet (58) to a channel outlet (60) and in that the valve body (66) is movably arranged to release and interrupt the flow communication between the channel inlet (58) and the channel outlet (60).

14. Liquid pump according to claim 13, characterized in that the liquid pump (10) has a sensor device (92) and the valve body (66) by means of the sensor device (92) in at least two positions within the flow channel (56) can be detected.

15. A liquid pump according to claim 14, characterized in that by means of the sensor device (92) positioning of the valve body (66) in a predetermined rest position of a positioning of the valve body (66) is arranged in a closed position disposed upstream of the rest position.

16. A liquid pump according to claim 14 or 15, characterized in that by means of the sensor device (92) positioning of the valve body (66) in a predetermined rest position of a positioning of the valve body (66) is arranged in a release position arranged downstream of the rest position.

17. Liquid pump according to one of claims 14 to 16, characterized in that the sensor device (92) has at least two sensor elements (94, 96) which are arranged in the flow direction of the liquid at a distance from each other.

18. Liquid pump according to claim 17, characterized in that the sensor elements (94, 96) have non-overlapping detection areas for detecting the valve body (66).

19. Liquid pump according to claim 17 or 18, characterized in that the chronological order of the sensor elements (94, 96) provided sensor signals by means of the control device (24) can be determined.