CN110418895B

CN110418895B - Pump assembly

Info

Publication number: CN110418895B
Application number: CN201880018500.4A
Authority: CN
Inventors: 托马斯·布拉德; 彼得·蒙斯特
Original assignee: Grundfos Holdings AS
Current assignee: Grundfos Holdings AS
Priority date: 2017-03-14
Filing date: 2018-03-12
Publication date: 2020-11-20
Anticipated expiration: 2038-03-12
Also published as: US20200072227A1; EP3376040A1; CN110418895A; EP3376040B1; WO2018166969A1

Abstract

The invention relates to a pump assembly having an electric drive motor, at least one impeller (14) which is rotationally driven by the electric drive motor, and a control device (17) which controls the drive motor, wherein the control device (17) is designed such that it selectively controls the drive motor in at least one first or second operating mode, wherein in the first operating mode the drive motor is controlled by the control device (17) such that a rotor (6) of the drive motor rotates continuously, and in the second operating mode the drive motor is controlled by the control device (17) such that the rotor (6) of the drive motor continues to move step by step in selected angular steps, preferably in angular steps of less than 360 °.

Description

Pump assembly

Technical Field

The invention relates to a pump assembly having an electric drive motor, at least one impeller which is driven in rotation by the electric drive motor, and a control device which actuates the drive motor.

Background

In modern pump assemblies, it is known to actuate the drive motor via a control device having a frequency converter, so that the drive motor can be adjusted and regulated with respect to its rotational speed. However, the speed range in which the rotational speed is variable is delimited.

Disclosure of Invention

The object of the invention is to improve a pump assembly having an electric drive motor in such a way that the drive motor is adjustable or drivable over a large rotational speed range.

The object of the invention is achieved by a pump assembly having the features according to the invention. Preferred embodiments will be apparent from the following description and the accompanying drawings.

The pump assembly according to the invention has an electric drive motor and at least one impeller which is driven in rotation by the electric drive motor. For this purpose, the impeller can be connected in a known manner to the rotor of the drive motor. The rotor is particularly preferably a permanent magnet rotor. Further preferably, the drive motor is designed as a wet-running electric drive motor having a can or can separating the rotor chamber from the stator chamber. That is, the rotor preferably rotates in the liquid to be delivered by the pump assembly. The pump assembly can preferably be designed as a circulation pump assembly and further preferably as a heating circulation pump assembly.

According to the invention, a control device of the drive motor controls the drive motor and in particular the energization of the stator coils in the stator of the drive motor, which control device is designed such that it selectively controls the drive motor in at least one first operating mode or in a second operating mode. Here, the first operation mode is a conventional operation mode in which the drive motor is controlled by the control device such that the rotor of the drive motor continuously rotates for a plurality of revolutions. In this operating mode, the impeller is driven in such a way that it generates the pressure and flow rate desired for the operation of the pump assembly. In contrast, in the second operating mode, the control device actuates the drive motor in such a way that the rotor of the drive motor continues to move only in steps with at least one selected, in particular adjustable, angular step, wherein the angular step is preferably less than 360 degrees. This rotation in at least one selected angular step serves to rotate the rotor into the desired angular position. This makes it possible for the drive motor to assume further drive functions and in particular adjustment functions in the second operating mode, as can be assumed in general, for example, by a stepping motor. This enables other application areas. The drive motor in the pump assembly can therefore also assume, in addition to the drive of the impeller, further functions, in particular a regulating function for moving further components which only have to be moved over a relatively small path.

Preferably, the control device is designed such that the drive motor rotates in the first operating mode at a higher angular speed than in the second operating mode. This is advantageous for the drive and adjustment function, in which smaller movements should be carried out with greater precision.

The control device is further preferably designed such that in the first operating mode the drive motor is adjustable and preferably adjustable in its rotational speed. For this purpose, the drive motor can preferably have a frequency converter in its control device, by means of which the rotational speed of the drive motor can be varied.

Furthermore, the control device is preferably designed such that the drive motor is controlled in the second operating mode by the control device in an open-loop manner, that is to say in a so-called open-loop operation in which no position adjustment is carried out when the stator coils are energized. In particular, no induced Back-EMF is used in the control or regulation in the case of open-loop operation. This control makes it possible to rotate the drive motor in a targeted manner at a specific angle by correspondingly energizing the coils in the stator. The stator can be provided in a known manner with a plurality of stator poles and associated stator coils, which are designed, for example, for three-phase operation.

According to a further preferred embodiment, the control device is designed such that in the second operating mode the drive motor is actuated by the control device at a frequency of <10 hz. I.e. a voltage or current with a frequency <10 hz is applied to the stator coils. Alternatively or additionally, a higher motor current is used than in the first operating mode. In this operating mode, therefore, the stator coils can be energized with a motor current which corresponds to a double to quadruple nominal current intensity for which the drive motor is designed. If necessary, the current intensity can also be four times higher than the nominal current intensity. The current intensity is limited essentially only in such a way that demagnetization of the rotor is not permitted.

According to a further preferred embodiment, the control device is designed such that the number and/or size of the individual angular steps to which the rotor is moved in the second operating mode is selectable. The rotor can thus be rotated in a targeted manner into a desired angular position. For this purpose, the control device selectively energizes the individual stator coils.

The control device can be designed such that it actuates the drive motor in such a way that its direction of rotation in the second operating mode is opposite to the direction of rotation in the first operating mode. This makes it easier to use different operating modes for different applications, since, in addition to the impeller, for example, other components can be coupled to the rotor by means of a coupling which is dependent on the direction of rotation, so that only the rotor is driven in one direction of rotation, while in the other direction of rotation, which is preferably used in the second operating mode, the other coupled component can also be moved.

The pump assembly therefore preferably has a further movable component which, in addition to the at least one rotor, is coupled to the rotor of the drive motor via a releasable coupling. The coupling can be in direct contact with the rotor, with a rotor shaft connected to the rotor, or with an impeller arranged on the rotor shaft in a rotationally fixed manner. The at least one further movable component may be, for example, a valve element, wherein the valve element is preferably a component of a mixing and/or switching valve. Such a switching valve may be, for example, a switching valve used in a heating installation for switching a flow path between a heating circuit and a non-potable water heat exchanger. The mixing valve may be, for example, a mixing valve as used in a heating plant in order to regulate the inflow temperature of the heating medium by mixing the cooled heating medium.

The coupling for coupling at least one further movable component is preferably releasable in relation to the direction of rotation, so that the additional component can be moved in the described manner in one direction of rotation, while in the opposite direction of rotation, which is preferably used in the first mode of operation, the impeller can be rotated in normal operation and can provide the pump function unaffected. The impeller may have blades which are adapted to the preferred direction of rotation for normal operation.

The coupling can also preferably be configured on the tip end of the rotor shaft of the rotor. The component to be moved then has a corresponding counter-coupler, which can be engaged with the coupler. In this case, the additional movable component is preferably likewise rotatable and further preferably rotatable about the same axis as the rotor shaft. The coupling on the tip end of the rotor shaft can in particular have a sawtooth profile, that is to say a sawtooth profile when expanded in the circumferential direction. Preferably, the profile has two inclined surfaces, the axially projecting tip edges of which extend along a diametrical line transverse to the axis of rotation of the rotor shaft. Thus, preferably, starting from these tip edges, abutment surfaces are provided which extend in a plane parallel to the axis of rotation and parallel to the diameter of the rotor shaft. Away from these engagement faces, a bevel or wedge-shaped face may extend from the top edge of the profile, which in the opposite direction of rotation causes the coupling to be pressed out of engagement. This disengagement is then performed by axial movement of the counter coupling and/or the coupling on the rotor shaft.

According to a particularly preferred embodiment, the additionally rotationally movable component is a valve element which is constructed and arranged such that it can be rotationally moved between at least two switching positions. The axis of rotation of the valve element is preferably aligned with the axis of rotation of the drive motor. This enables a simple structure of the coupling. The valve element is preferably additionally axially displaceable along its axis of rotation, wherein, for example, a coupling as described above can be disengaged by axial displacement of the valve element.

According to a further preferred embodiment, the valve element is arranged in the pump assembly in such a way that it has a pressure surface, on which the pressure prevailing on the outlet side of the at least one impeller acts. That is, the pressure surface preferably abuts the pressure chamber in which the impeller rotates. The valve element is preferably mounted so as to be movable in a direction transverse to the pressure surface between an abutment position, in which the valve element abuts at least one abutment surface, and a release position, in which the valve element is released or spaced apart from the abutment surface. The movement path along which the valve element can be moved between the contact position and the release position is preferably different from the movement path between the at least two switching positions of the valve element. Particularly preferably, the valve element is axially movable along a rotational axis, about which the valve element is movable between the switching positions.

Furthermore, a restoring or prestressing element is preferably provided, which generates a restoring force that is directed counter to the pressing force generated by the pressure on the pressure surface. Such a restoring element may be, for example, a spring. The restoring element is preferably arranged in such a way that the restoring force generated presses the valve element into the release position. In the release position, the valve element is preferably substantially freely movable and in particular rotatable, so that it can be easily moved between its switching positions. In the rest position, the valve element is, on the other hand, preferably held on the rest surface in a force-fitting and/or form-fitting manner, so that the valve element is fixed in the switching position it occupies.

The at least one contact surface can preferably be a sealing surface at the same time. In this way, the valve element is simultaneously sealed in the desired switching position, wherein the sealing surface preferably surrounds the inlet opening or the switching opening and acts as a valve seat.

The pump assembly according to the invention makes it possible to operate the drive motor according to a novel method, which is likewise the subject of the invention. The main method features result from the above description of the function of the pump assembly. The second operating mode is preferably used to move the additional component, in particular the valve element, into a desired position, in particular a desired angular position with respect to the axis of rotation. For this purpose, an open-loop operation is used when the drive motor is actuated. At the same time, a coupling is preferably provided between the rotor and the rotatable valve element, as described above, which coupling is dependent on the direction of rotation. The coupling is designed such that it engages in at least one angular position, in the above-described embodiment, in two angular positions offset by 180 °. Since in normal operation the coupling is disengaged in the first operating mode by the pressure prevailing in the pressure chamber in the manner described above, it cannot be ensured that the valve element does not move slightly when changing over into the second operating mode. In this connection, it is preferred that at the beginning of the second operating mode the drive motor is not rotated exactly into the angular position it was in at the last end of the second operating mode, but rather is driven into an angular position that has been moved back to a certain extent. Thus, at the start of the second operating mode, this orientation of the rotor is first carried out in an angular position which is slightly earlier than the angular position at which the rotor was in the last rest operation of the second operating mode. This ensures that, on further rotation, the coupling engages in any case and the valve element is moved in the desired manner.

From the initial position, the rotor is then rotated precisely into the desired new angular position by the control device by corresponding energization of the stator coils in the manner described above. This is preferably carried out in a time-controlled manner, by energizing the stator at a predetermined frequency for a time interval determined by the control device, wherein the frequency preferably moves within the above-mentioned very low range. After the desired angular position has been reached, the rotor is stopped and switched back into the first operating mode, in which it is preferably rotated in the opposite rotational direction, so that the coupling is disengaged and the valve element is held in the reached switching position by the pressure in the pressure chamber in the described manner. By this method, the valve element can be positioned very precisely, so that various most different switching functions, such as a changeover function, a switching function of the distributor valve and/or an adjustment of the mixing valve, can be carried out.

Drawings

The invention is described below by way of example with the aid of the accompanying drawings. In which is shown:

figure 1 shows an exploded view of a centrifugal pump assembly according to a first embodiment of the invention,

fig. 2 shows a perspective view of the centrifugal pump assembly according to fig. 1, with the pump housing and the valve element removed,

figure 3 shows a perspective view of the motor shaft of the centrifugal pump unit according to figures 1 and 2 and the coupling part of the valve element,

fig. 4 shows a cross-sectional view of the centrifugal pump assembly according to fig. 1, with the valve element in a first position,

fig. 5 shows a sectional view according to fig. 4, with the valve element in a second position,

fig. 6 shows a plan view of an open pump housing of the centrifugal pump assembly according to fig. 1 to 3, with the valve element in a first switching position,

fig. 7 shows the view according to fig. 6, with the valve element in the second switching position,

fig. 8 shows the views according to fig. 6 and 7, with the valve element in a third switching position,

figure 9 shows schematically the hydraulic structure of a heating installation with a centrifugal pump assembly according to figures 1 to 8,

figure 10 shows an exploded view of a centrifugal pump assembly according to a second embodiment of the present invention,

figure 11 shows a perspective view of an open valve element of the centrifugal pump assembly according to figure 10,

figure 12 shows a perspective view of the closed valve element according to figure 11,

fig. 13 shows a cross-sectional view of the centrifugal pump assembly according to fig. 10, with the valve element in the first position,

fig. 14 shows a sectional view according to fig. 13, with the valve element in the second position,

fig. 15 shows a plan view of an open pump housing of the centrifugal pump assembly according to fig. 10 to 14, with the valve element in a first switching position,

fig. 16 shows the view according to fig. 15, with the valve element in the second switching position,

fig. 17 shows the views according to fig. 15 and 16, with the valve element in the third switching position,

fig. 18 shows the views according to fig. 15 to 17 with the valve element in a fourth switching position, an

Fig. 19 schematically shows the hydraulic structure of a heating installation with a centrifugal pump assembly according to fig. 10 to 18.

Detailed Description

The exemplary embodiments of the centrifugal pump assembly according to the invention described in the following description relate to the use in a heating and/or air conditioning system in which a liquid heat carrier, in particular water, is circulated by the centrifugal pump assembly.

The centrifugal pump assembly according to both embodiments of the invention has a motor housing 2 in which an electric drive motor is arranged. The electric drive motor has a stator 4 and a rotor 6, which is arranged on a rotor shaft 8, in a known manner. The rotor 6 rotates in a rotor chamber, which is separated from a stator chamber in which the stator 4 is arranged by a can or can 10. In other words, a wet-running electric drive motor is provided. At one axial end, the motor housing 2 is connected to a pump housing 12, in which an impeller 14, which is connected to the rotor shaft 8 in a rotationally fixed manner, rotates.

At the axial end of the motor housing 2 opposite the pump housing 12, an electronics housing 16 is arranged, which contains control electronics or a control device 17 for actuating the electric drive motor in the pump housing 2. The electronics housing 16 can also be arranged in a corresponding manner on the other side of the stator housing 2.

Furthermore, a movable valve element 18 is arranged in the pump housing 12. The valve element 18 is rotatably mounted on a shaft 20 inside the pump housing 12, specifically, such that the axis of rotation of the valve element 18 is aligned with the axis of rotation X of the impeller 14. The shaft 20 is fixed in a rotationally fixed manner at the bottom of the pump housing 12. The valve element 18 is not only rotatable about the axis 20 but also movable to a certain extent in the longitudinal direction X. In one direction, this linear movability is delimited by the pump housing 12, to which the valve element 18 is stopped with its outer circumference.

Valve element 18 separates suction chamber 24 from pressure chamber 26 in pump housing 12. The impeller 14 rotates in the pressure chamber 26. The pressure chamber 26 is connected to a pressure connection or pressure connection 27 of the centrifugal pump unit, which forms the outlet of the centrifugal pump unit.

In the two exemplary embodiments shown, a mechanical coupling is provided between the drive motor and the valve element, wherein in these exemplary embodiments the drive motor can be actuated by the control device 17 in two different operating modes or operating modes. In a first operating mode, which corresponds to normal operation of the circulation pump unit, the drive motor is rotated in a conventional manner at a desired rotational speed, which is in particular adjustable by the control device 17. In a second operating mode, the drive motor is controlled in an open-loop operation such that the rotor can be rotated in individual angular steps of less than 360 °, which are predetermined by the control device 17. The drive motor can thus be moved in individual steps in the manner of a stepper motor, which in these exemplary embodiments is used to move the valve element in targeted small angular steps into defined positions, as described below.

In the first embodiment according to fig. 1 to 9, a mixing valve is integrated in the pump housing 2, which mixing valve can be used for temperature regulation for floor heating, for example.

The motor housing 2 with the electronics housing 16 corresponds to the embodiment described above. In addition to the pressure connection 27, the pump housing 12 also has two suction-

side connections

32 and 34, which open out at the bottom of the pump housing 12 into the

inlets

28 and 30 in a plane transverse to the axis of rotation X.

The valve element 18 is of drum-shaped design and comprises a pot-shaped lower part 76 which is closed on its side facing the impeller 14 by a top cover 78. In a central region of the cover 78, the suction opening 36 is formed. The suction opening 36 engages with a suction mouth 38 of the impeller 14. The valve element 18 is rotatably supported on a shaft 20 disposed in the bottom of the pump housing 12. The axis of rotation of the valve element 18 corresponds here to the axis of rotation X of the rotor shaft 8. The valve element 18 is likewise axially displaceable along the axis X and is pressed by the spring 48 into the rest position shown in fig. 5, in which the valve element 18 is in a released position, in which the lower part 76 does not bear against the bottom of the pump housing 12, so that the valve element 18 is substantially freely rotatable about the shaft 20. In the release position, the tip end of the rotor shaft 8, which is designed as the coupling 108, serves as an axial stop. The coupling 108 engages with a counter coupling 110, which is arranged on the valve element 18 in a rotationally fixed manner. The coupling 108 has an inclined coupling surface which essentially describes a sawtooth profile along the circumferential line in such a way that a transmission of torque from the coupling 108 to the counter-coupling 110 is possible only in one direction of rotation, i.e. in the direction of rotation a in fig. 3. Instead, the coupling slips in the opposite rotational direction B, wherein an axial movement of the valve element 18 occurs. The direction of rotation B is the direction of rotation in which the pump unit is driven in normal operation. Instead, the direction of rotation a is used for the targeted adjustment of the valve element 18. In other words, the coupling is formed in this case as a function of the direction of rotation. Additionally, however, the counterpart coupling 110 is disengaged from the coupling 108 by the pressure in the pressure chamber 26. If the pressure in the pressure chamber 26 rises, a pressing force acts on the cover 78, which pressing force opposes and exceeds the spring force of the spring 48, so that the valve element 18 is pressed into the contact position, which is shown in fig. 4. In this contact position, the lower part 76 contacts the bottom side of the pump housing 12, so that, on the one hand, the valve element 18 is held in a force-fitting manner and, on the other hand, a sealing contact is achieved, which seals the pressure side and the suction side against one another in the manner described below.

The suction connection 32 opens at the inlet 28 and the suction connection 34 opens at the inlet 30 into the interior of the pump housing 12 in the bottom thereof, i.e. into the suction chamber 24. The lower portion 76 of the valve element 18 has an arcuate opening 112 in its bottom portion that extends substantially over 90 °. Fig. 6 shows a first switching position in which the opening 112 covers only the inlet 30, thereby giving a flow path only from the suction interface 34 to the suction opening 36 and thus to the suction mouth 38 of the impeller 14. The second inlet 28 is sealingly closed by the bottom of the valve element 18 abutting in a peripheral region of the second inlet. Fig. 8 shows a second switching position in which the opening 112 covers only the inlet 28, while the inlet 30 is closed. In this switching position, only the flow path from the suction connection 32 towards the suction mouth 38 is open. Fig. 7 now shows an intermediate position in which the opening 112 covers both

inlets

28 and 30, wherein the inlet 30 is only partially released. By varying the degree of release of the interface 30, the mixing ratio between the fluids from the

inlets

28 and 30 can be varied. The valve element 18 can also be adjusted in small steps by stepwise adjustment of the rotor shaft 8 in order to change the mixing ratio.

Such a function may be applied, for example, in a hydraulic system as shown in fig. 9. There, the centrifugal pump assembly with integrated valve is represented by the dashed line 1 as described above. The hydraulic circuit has a heat source 114, for example in the form of a gas-fired heating boiler, the outlet of which opens into the suction connection 34 of the pump housing 12, for example. In this example, the floor heating circuit 116 is connected to the pressure connection 27 of the centrifugal pump unit 1, and the return flow of the floor heating circuit 116 connects the inlet of the heat source 114 and the suction connection 32 of the centrifugal pump unit. Via the second circulation pump unit 118, a further heating circuit 120 can be supplied with a heat carrier, which has the outlet-side temperature of the heat source 114. Conversely, floor heating circuit 116 can be regulated in its inflow temperature in such a way that cold water from the return flow is mixed with hot water at the output side of heat source 114, wherein, by changing the opening ratio of

inlets

28 and 30 in the manner described above, the mixing ratio can be changed by rotation of valve element 18 h.

The second exemplary embodiment according to fig. 10 to 19 shows a centrifugal pump assembly which, in addition to the mixing function described above, also has a switching function for additionally supplying a secondary heat exchanger for heating the service water.

The support and actuation of the valve element 18i in this embodiment is performed exactly as in the ninth embodiment. In contrast to the valve element 18, the valve element 18i has, in addition to the opening 112, a through-channel 122 which extends from an opening 124 in the top cover 78i to an opening in the bottom of the lower part 76i and thus connects the two axial ends of the valve element 18i to one another. Furthermore, an arcuate bridging opening 126, which opens only to the underside, i.e. to the bottom of the lower part 76i and thus to the suction chamber 24, is also formed in the valve element 18i, said bridging opening being closed by the cover 78i to the pressure chamber 26.

In addition to the pressure connection 27 and the two previously described

suction connections

34 and 32, the pump housing 12 also has a further connection 128. In addition to the

inlets

28 and 30, the connection 128 opens into the suction chamber 24 at an inlet 130 in the bottom of the circulation pump assembly 12. The different switching positions are explained with the aid of fig. 15 to 18, in which the cover 78i of the valve element 18i is shown partially open in order to illustrate the position of the opening located therebelow. Fig. 15 shows a first switching position in which the opening 112 is opposite the inlet 30, so that a flow connection is established from the suction connection 34 to the suction mouth 38 of the impeller 14. In the switching position according to fig. 16, the opening 112 is located above the inlet 130, so that a flow connection is provided from the connection 128 to the suction opening 36 and through this into the suction mouth 38 of the impeller 14. In a further switching position shown in fig. 17, the opening 112 is located above the inlet 30, so that a flow connection is in turn provided from the suction connection 34 to the suction mouth 38 of the impeller 14. At the same time, the opening 124 and the passage opening 122 partially cover the inlet 28, so that a connection is established between the pressure chamber 26 and the suction connection 32, which serves here as a pressure connection. At the same time, crossover opening 126 covers both inlet 130 and a portion of inlet 28 such that a connection is also provided from interface 128 to interface 32 via inlet 130, crossover opening 126, and inlet 28.

Fig. 18 shows a fourth switching position, in which the through-channel 122 completely covers the inlet 28, so that the interface 32 is connected with the pressure chamber 26 via the through-channel 122 and the opening 124. At the same time, the crossover opening 126 only covers the inlet 130 as well. Opening 112 also covers inlet 30.

Such a centrifugal pump unit can be used, for example, in heating systems, as is shown in fig. 19. There, the dashed line delimits the centrifugal pump assembly 1, as it has just been described with the aid of fig. 10 to 18. The heating system in turn has a main heat exchanger or heat source 114, which may be, for example, a gas-fired heating boiler. On the output side, the flow path extends into a first heating circuit 120, which can be formed, for example, by a conventional heating body or a radiator. At the same time, a flow path leading to the secondary heat exchanger 56 for heating the service water is branched off. The heating system also has a floor heating circuit 116. The return flows of the heating circuit 120 and of the floor heating circuit 116 open into the suction connection 34 at the pump housing 12. The return flow from the secondary heat exchanger 56 is to an interface 128 that provides two functions, as will be described below. The interface 32 of the pump housing 12 is connected to the inflow of the floor heating circuit 116.

When the valve element 18i is in the first switching position shown in fig. 15, the impeller 14 conveys liquid from the suction connection 34 via the pressure connection 27 through the heat source 140 and the heat supply circuit 120 and back to the suction connection 34. If the valve element 18i is in the second switching position (this is shown in fig. 16), the device is switched to non-potable water operation, in which state the pump assembly or impeller 14 conveys liquid from the connection 128 serving as a suction connection through the pressure connection 27, via the heat source 114 through the secondary heat exchanger 56 and back to the connection 128. If the valve element 18i is in the third switching position (as shown in fig. 17), the floor heating circuit 116 is additionally supplied. Water flows into the suction mouth 38 of the impeller 14 via the suction connection 34 and is conveyed through the first heating circuit 120 via the heat source 114 via the pressure connection 27 in the described manner. At the same time, liquid flows on the outlet side of the impeller 14 from the pressure chamber 26 into the opening 124 and through the through-channel 122 and thus to the connection 32 and via this into the floor heating circuit 116.

In the switching position shown in fig. 17, liquid flows simultaneously via the crossover opening 126 via the connection 128 and the inlet 130 into the connection 32. That is, here, water flows through secondary heat exchanger 26 and interface 128 to interface 32 via heat source 114. Since in this heating mode substantially no heat is reduced in the secondary heat exchanger 56, the connection 32 is mixed with hot water in addition to the cold water flowing from the pressure chamber 26 via the through-channel 122 to the connection 32. By varying the opening degree via the valve position 18i, the amount of hot water mixed at the interface 32 can be varied. Fig. 18 shows the switching position in which the mixing is switched off and the connection 32 is connected directly only to the pressure chamber 26. In this state, the water in the floor circuit 116 is transported in the circuit without heat input. It can be seen that in this embodiment, by changing the switching position of the valve element 18i, both a changeover between heating and service water heating can be achieved, as well as a simultaneous supply of different temperatures to the two heating circuits, namely the first heating circuit 120 with the initial temperature of the heat source 114 and the floor heating circuit 116 with the temperature reduced by the mixing function.

Due to the fact that the coupling 108 and the counter-coupling 110 are disengaged in the first operating mode during normal operation of the circulation pump assembly when the impeller 14 is delivering liquid, the problem arises that the rotor 6 and the

valve elements

18, 18i are again brought into a defined orientation with respect to their angular position when changing to the second operating mode, which requires a reversal of the direction of rotation. The

valve elements

18, 18i should essentially be held in the position of the valve elements when the pump assembly was last changed from the second operating mode to the first operating mode by the control device 17. At the same time, the control device 17 knows the position of the rotor 6, and the control device 17 is configured such that it stores the rotor position. However, since it cannot be completely ruled out that the

valve elements

18, 18i may have already been moved to a small extent, when switching back to the second operating mode, the positioning of the rotor 6 is preferably carried out first in such a way that the control device 17, by actuating the stator 4 accordingly, does not completely rotate the rotor 6 into the stored angular position, but rather preferably stops it a short distance before this. That is, in the first step, when the second operation mode is put into operation, the rotor 6 is rotated into the previously stored angular position or into an angular position slightly before the last stored angular position in the rotation direction. Subsequently, the rotor can be rotated together with the

valve elements

18, 18i into a desired second angular position, wherein the control device 17 actuates the stator 6 in such a way that the rotor 6 is rotated exactly by the desired angle in this second operating mode. In this rotation, the counter-coupling 110 is entrained by the coupling 108, so that the

valve elements

18, 18i are then rotated into the desired angular position. In this angular position, the rotor 6 is stopped, and the control device 17 switches back into the first operating mode, or first operating mode, and activates the rotor 6 in the opposite rotational direction, so that the coupling 108 can be disengaged from the counter-coupling 110, and in addition, the coupling 108 and the counter-coupling 110 are completely disengaged by the pressure generated in the pressure chamber 26 by the axial displacement of the

valve elements

18, 18i, and the

valve elements

18, 18i are held in the achieved switching position by abutting against the bottom of the pump housing 12.

The coupling 108 has two ramps or wedge surfaces 132, the ramps or wedge surfaces 132 extending from two tip edges 134 that extend substantially diametrically about the axis of rotation X. On the side of the tip edge 134 facing away from the wedge surface 132, engagement surfaces 136 extend, which essentially extend in a plane spanned by the axis of rotation X and a diametrical line relative to the axis of rotation X. The counter-coupler 110 has a tab-like projection 138 which extends diametrically with respect to the axis of rotation X, projects in an axial direction and has two side faces which are substantially parallel to one another and which in turn extend in planes which are substantially spanned by the diametrical line and the axis of rotation X or an axis parallel thereto. When the coupling is engaged, the sides of the projections 138 bear against the engagement faces 136. In the opposite direction of rotation D, the projection 138 slips on the wedge surface 137 with an axial displacement. In this design of the coupling 108 and the counter-coupling 110, there are exactly two positions which are offset by 180 ° from one another, in which the rotor 6 and the

valve elements

18, 18i can be coupled to one another.

In the above embodiment, the pump housing 12 is integrally constructed. It should be understood, however, that the pump housing may be constructed of multiple pieces. In particular, a valve housing can be provided which is separate from the pump housing, in which valve housing the valve element is arranged, while only the impeller is arranged in the pump housing. Such a valve housing and pump housing can be connected to one another in a suitable manner.

List of reference numerals

1 centrifugal pump unit

2 Motor casing

4 stator

6 rotor

8 rotor shaft

10-seam tube

12 pump casing

14 impeller

16 electronic device case

17 control device

18. 18i valve element

20 shaft

24 suction chamber

26 pressure chamber

27 pressure interface

28. 30 inlet

32. 34 suction interface

38 suction nozzle

48 spring

78. 76i lower part

78. 78i Top cover

108 coupler

110 mating coupler

112 opening

114 heat source

116 floor heating circuit

118 circulating pump unit

120 heating loop

122 through channel

124 opening

126 across the opening

128 interface

130 inlet

132 wedge-shaped surface

134 top edge

136 engagement surface

138 projection

Axis of rotation of X

A. Direction of rotation B

Claims

1. Pump assembly having an electric drive motor, at least one impeller (14) which is driven in rotation by the electric drive motor, and a control device (17) which actuates the drive motor,

wherein the control device (17) is designed such that it selectively actuates the drive motor in at least one first operating mode or in a second operating mode, wherein in the first operating mode the drive motor is controlled by the control device (17) such that the rotor (6) of the drive motor continuously rotates to generate a flow and a pressure at the impeller, and in the second operating mode the drive motor is controlled by the control device (17) such that the rotor (6) of the drive motor gradually continues to move in at least one selected angular step of less than 360 ° to a specific angular position,

it is characterized in that the preparation method is characterized in that,

the rotor (6) of the drive motor is coupled to at least one further movable component in addition to the at least one impeller (14) by means of a releasable coupling (108, 110).

2. Pump assembly according to claim 1, characterized in that the control device (17) is configured such that the drive motor rotates at a higher angular speed in the first operating mode than in the second operating mode.

3. Pump assembly according to claim 1, characterized in that the control device (17) is configured such that in the first operating mode the drive motor is adjustable in its rotational speed.

4. Pump assembly according to claim 1, characterized in that the control device (17) is configured such that the drive motor is controlled in an open-loop manner by the control device (17) in the second operating mode.

5. Pump assembly according to any one of claims 1 to 4, characterized in that the control device (17) is configured such that, in the second operating mode, the drive motor is actuated by the control device (17) at a frequency of less than 10Hz and/or the motor current corresponds to two to four times the nominal current intensity for which the drive motor is designed.

6. Pump assembly according to any one of claims 1 to 4, characterized in that the control device (17) has a frequency converter.

7. Pump assembly according to any one of claims 1 to 4, characterized in that the control device (17) is configured such that the number and/or size of the individual angular steps in which the rotor (6) is moved in the second operating mode can be selected.

8. Pump assembly according to any one of claims 1 to 4, characterized in that the control device (17) is configured such that it commands the drive motor such that its direction of rotation is opposite in the second operating mode to that in the first operating mode.

9. Pump assembly according to claim 1, characterized in that the coupling (108, 110) is releasable depending on the direction of rotation, such that the coupling is engaged in a first direction of rotation and released in a second, opposite direction of rotation.

10. Pump assembly according to claim 1, characterized in that the coupling (108) is configured on the tip end of the rotor shaft (8) of the rotor and has a saw-tooth profile.

11. Pump assembly according to claim 1, characterized in that the at least one further movable component is a valve element (18; 18 i).

12. Pump assembly according to claim 11, characterized in that the valve element (18; 18i) is a component of a mixing valve and/or a changeover valve.

13. Pump assembly according to claim 11, characterized in that the valve element (18; 18i) is constructed and arranged such that it can be rotationally moved between at least two switching positions, wherein the axis of rotation of the valve element (18; 18i) is arranged in alignment with the axis of rotation of the drive motor.

14. Pump assembly according to claim 11, characterized in that the valve element (18; 18i) is arranged in the pump assembly such that it has a pressure face (78; 78i), the pressure prevailing on the output side of the at least one impeller (14) acts on the pressure surface, and the valve element (18; 18i) is mounted so as to be movable between an abutment position and a release position in a direction transverse to the pressure surface (78; 78i), in which the valve element rests against at least one abutment surface, and in which the valve element is released or spaced apart from the abutment surface, wherein a restoring element (48) is provided, which generates a restoring force that is directed counter to a pressing force generated by the pressure on the pressure surface (78; 78 i).

15. The pump assembly of claim 14, wherein the abutment surface is a sealing surface.

16. Pump assembly according to claim 14, characterized in that the movement path between the abutment position and the release position differs from the movement path between at least two switching positions of the valve element (18; 18 i).

17. Pump assembly according to any one of claims 1 to 4, characterized in that the pump assembly is configured as a circulation pump assembly.

18. The pump assembly of claim 17, wherein the pump assembly is configured as a thermal cycle pump assembly.