WO2018166969A1

WO2018166969A1 - Pump assembly

Info

Publication number: WO2018166969A1
Application number: PCT/EP2018/056080
Authority: WO
Inventors: Thomas Blad; Peter Mønster
Original assignee: Grundfos Holding A/S
Priority date: 2017-03-14
Filing date: 2018-03-12
Publication date: 2018-09-20
Also published as: EP3376040A1; CN110418895A; US20200072227A1; CN110418895B; EP3376040B1

Abstract

The invention relates to a pump assembly with an electric drive motor, at least one impeller (14) which is rotated by the electric drive motor, and a controller (17) which actuates the drive motor. The controller (17) is designed to selectively actuate the drive motor in at least one first or second operating mode. In the first operating mode, the drive motor is controlled by the controller (17) such that a rotor (6) of the drive motor is continuously rotated, and in the second operating mode, the drive motor is controlled by the controller (17) such that the rotor (6) of the drive motor is moved incrementally in selected angular steps of preferably less than 360°.

Description

pump unit

description

The invention relates to a pump unit with an electric drive motor, at least one impeller rotatably driven by the electric drive motor and a control device which controls the drive motor. In modern pump units, it is known to drive the drive motor via a control device with a frequency converter, so that the drive motor can be adjusted in its speed and regulated. However, the speed range over which the speed is variable is limited. [03] It is an object of the invention to improve a pump unit with an electric drive motor to the effect that the drive motor can be set or driven over a larger speed range.

[04] This object is achieved by a pump unit having the features specified in claim 1. Preferred embodiments will become apparent from the subclaims, the following description and the accompanying figures.

[05] The pump unit according to the invention has an electric drive motor and at least one impeller driven in rotation therewith. For this purpose, the impeller may be connected in a known manner with the rotor of the drive motor. The rotor is particularly preferably a permanent magnet rotor. Further preferred is the drive motor as a wet-running electric drive motor with a split tube or split pot, which separates the rotor space from the stator, is formed. That is, the rotor preferably rotates in the fluid to be delivered by the pump unit. The pump unit may preferably be designed as a circulating pump unit and more preferably as a heating circulation pump unit.

[06] According to the invention, the control device of the drive motor, which controls the drive motor and in particular controls the energization of stator coils in the stator of the drive motor, is designed such that it selectively drives the drive motor in at least one first or in a second operating mode. Here, the first mode is a conventional mode in which the drive motor is controlled by the controller such that the rotor of the drive motor rotates continuously over a plurality of revolutions. In this mode, the impeller is driven to produce the pressure and flow desired to operate the pump set. In the second operating mode, however, the control device controls the drive motor in such a way that the rotor of the drive motor is moved only stepwise in at least one selected, in particular adjustable angle step, wherein these angular steps are preferably less than 360 degrees. This rotation in at least one selected angular step serves to rotate the rotor to a desired angular position. This makes it possible for the drive motor in the second operating mode to take on additional drive functions and, in particular, actuating functions, as might otherwise be assumed, for example, by stepper motors. This allows further fields of application. Thus, the drive motor in the pump unit in addition to the drive of the impeller other functions, in particular control functions for moving other components take over, which only need to be moved over smaller ways. [07] Preferably, the control device is designed such that the drive motor in the first operating mode rotates at a higher angular speed than in the second operating mode. This is advantageous for drive and positioning functions in which smaller movements are to be carried out with greater accuracy.

[08] The control device is further preferably configured such that in the first operating mode, the drive motor is adjustable in its rotational speed and preferably controllable. For this purpose, the drive motor in its control device preferably have a frequency converter, via which the speed of the drive motor is variable.

[09] The control device is also preferably designed so that the drive motor is controlled in the second mode by the control device in an open loop, that is in the so-called open-loop operation, in which no position control is performed in the energization of the stator coils. In particular, the induced reverse voltage (back-EMF) is not used in the control or regulation in open loop operation. This control makes it possible to turn the drive motor at specific angles in a targeted manner by 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.

[10] According to a further preferred embodiment, the control device is designed such that in the second operating mode, the drive motor is controlled by the control device with a frequency <10 hertz. That is, the stator coils are supplied with voltage or current with a frequency <10 Hertz. Alternatively or additionally, a higher motor current than in the first mode is used. Thus, in the operating mode, a motor current can be used or For example, the stator coils can be supplied with a current which corresponds to two to four times the nominal current for which the drive motor is designed. Optionally, the current may also be higher than four times the nominal current. It is essentially only limited by the fact that no demagnetization of the rotor may occur.

[1 1] According to a further preferred embodiment, the control device is designed such that the number and / or the size of the individual angular steps in which the rotor is moved in the second operating mode are selectable. So it is possible to rotate the rotor targeted to a desired angular position. For this purpose, the control device selectively energizes the individual stator coils.

[12] Further preferably, the control device can be configured such that it controls the drive motor so 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 the different operating modes for different applications, since, in addition to the impeller, for example, further components could be coupled to the rotor via a direction-dependent coupling, so that in one direction of rotation only the rotor is driven, while in the other direction of rotation , which is preferably used in the second mode, even a further coupled component could be moved.

[13] Thus, the pump unit preferably has a further movable component, which is coupled in addition to the at least one rotor via a releasable coupling with the rotor of the drive motor. In this case, the coupling can act directly on the rotor, on a rotor shaft connected to the rotor or on the impeller, which is arranged rotationally fixed on the rotor shaft. The at least one further movable component may for example be a valve element, wherein the valve element is preferably part of a mixing and / or switching valve. Such a changeover valve can be, for example, a changeover valve which is used in a heating system in order to switch over the flow path between a heating circuit and a service water heat exchanger. A mixing valve may for example be a mixing valve, as used in a heating system for the application to regulate the flow temperature of the heating medium by mixing in cooled heating medium.

The described coupling for coupling the at least one further movable component is preferably detachable depending on the direction of rotation, so that in one direction of rotation the additional component can be moved in the manner described while in the opposite direction of rotation, which is preferably used in the first mode, the The impeller can rotate in normal operation and can perform a pumping function without being disturbed. The impeller may have blades, which are adapted to these preferred for normal operation direction of rotation.

[15] The mentioned coupling can be further preferably formed on a front end of the rotor shaft of the rotor. The component to be moved then has a corresponding mating coupling, which can engage with this coupling. In this case, the additional movable component is preferably also rotatable and more preferably rotatable about the same axis as the rotor shaft. The coupling at the front end of the rotor shaft may in particular have a sawtooth profile, that is to say have a sawtooth profile in a development in the circumferential direction. Preferably, this profile has two slopes whose axially projecting end edges extend transversely to the axis of rotation of the rotor shaft along a diameter line. Thus, preferably, starting from these end edges, engagement surfaces are created which lie in a plane parallel to the axis of rotation and to the diameter of the rotor shaft. extend. Facing away from these engagement surfaces, starting from the end edges of the profile, the bevels or wedge surfaces may extend, which in the opposite direction of rotation cause the clutch is pressed out of engagement. This disengagement occurs then by an axial displacement of the counter-coupling and / or the coupling on the rotor shaft.

[16] According to a particularly preferred embodiment, the additionally rotationally moving component is a valve element, which is designed and arranged such that it can be moved in rotation between at least two switching positions. In this case, the axis of rotation of the valve element is preferably aligned with the axis of rotation of the drive motor. This allows a simple construction of the coupling described. The valve element is preferably additionally axially displaceable along its axis of rotation, wherein the axial displacement of the valve element, for example, a coupling, as described above, can be disengaged.

[17] According to a further preferred embodiment, the valve element is arranged in the pump unit such that it has a pressure surface on which an output side of the at least one impeller prevails pressure. That is, the pressure surface preferably adjoins the pressure space in which the impeller rotates. Furthermore, the valve element is preferably movably mounted in a direction transverse to the pressure surface between an abutment position in which it bears against at least one abutment surface and a released position in which it is detached or spaced from the abutment surface. The movement path, along which the valve element is movable between the adjacent position and the released position, preferably differs from the movement path between the at least two switching positions of the valve element. Especially Zug † is the valve element along the axis of rotation about which it is movable between the switching positions, axially movable.

[18] More preferably, a restoring or biasing element is provided, which generates a restoring force, which is directed opposite to the pressure force generated by the pressure on the pressure surface. Such a return element may for example be a spring. The return element is preferably arranged so that the restoring force generated presses the valve element in the released position. In the released position, the valve element is preferably substantially freely movable and in particular rotatable, so that it can be moved easily between its switching positions. In the adjacent position, however, the valve element is preferably held non-positively and / or positively on the contact surface, so that it is fixed in its assumed switching position. [19] The at least one contact surface may 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 an input or switching opening and acts as a valve seat. The pump unit according to the invention makes it possible to drive the drive motor according to a novel method, which is also the subject of the invention. In this case, the essential process features from the foregoing description of the function of the pump unit. The second operating mode is preferably used to move an additional component, in particular a valve element, into a desired position, in particular a desired angular position with respect to a rotation axis. For this purpose, the open-loop operation is used to control the drive motor. At the same time, it is preferable between the rotor and the rotatable valve Elemen † provided a direction-dependent coupling, as described above. The coupling is designed so that it engages in at least one angular position, in the embodiment described above in two angular positions offset by 180 °. Since, in normal operation in the first operating mode, the clutch is disengaged in the manner described above by the pressure prevailing in the pressure chamber, it is not certain when changing to the second operating mode that the valve element has not shifted slightly. In this respect, it is preferred that at the start of the second mode of operation, the drive motor is not rotated exactly in the angular position in which he was at the last time the end of the second mode of operation, but in an angular position moves, which is set back by a certain amount. At the beginning of the second operating mode, therefore, this orientation of the rotor initially takes place in an angular position slightly before the angular position in which the rotor was located when the second operating mode was last taken out of operation. This ensures that in the further rotation, the clutch engages in any case and the valve element is moved in the desired manner.

Starting from the described starting position, the rotor is then rotated by the control device by corresponding energization of the stator coils in the manner described above in exactly the desired new angular position. This is preferably time-controlled in that the stator is supplied with a predetermined frequency for a period of time determined by the control device, the frequency preferably being in the very low range mentioned above. After reaching the desired angular position of the rotor is stopped and changed back to the first mode in which the rotor is preferably rotated in the reverse direction, so that the clutch is disengaged and in the manner described by the pressure build-up in the pressure chamber, the valve element in the achieved Switch position is held. This procedure makes it possible to Very precisely position tilelement so that various switching functions, such as switching functions, switching functions of a distribution valve and / or settings of a mixer valve can be made. [22] The invention will now be described by way of example with reference to the accompanying drawings. In these shows:

1 is an exploded view of the centrifugal pump assembly according to a ninth embodiment of the invention,

2 is a perspective view of the Kreiselpumpenaggrega- tes of FIG. 1 with removed pump housing and valve element,

3 shows a perspective view of the motor shaft of the centrifugal pump assembly according to FIGS. 1 and 2 and of the coupling part of the valve element, FIG. 4 shows a sectional view of the centrifugal pump assembly according to FIG

1 with the valve element in a first position,

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

6 is a plan view of the open pump housing of

Centrifugal pump assemblies of FIG. 1 to 3 with the

Valve element in a first switching position,

7 shows a view according to FIG. 6 with the valve element in a second switching position, FIG. 8 shows a view according to FIGS. 6 and 7 with the valve element in a third switching position,

FIG. 9 schematically shows the hydraulic construction of a heating system with a centrifugal pump assembly according to FIGS. 1 to 8, FIG.

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

Hg. 1 1 is a perspective view of the open valve element of the centrifugal pump assembly of FIG. 10,

12 is a perspective view of the closed valve element of FIG. 1 1,

Fig. 13 is a sectional view of the centrifugal pump assembly according to

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

Fig. 15 is a plan view of the open pump housing of

Centrifugal pump assemblies according to FIGS. 10 to 14 with the valve element in a first switching position, FIG. 16 a view according to FIG. 15 with the valve element in a second switching position, 17 shows a view according to FIGS. 15 and 16 with the valve element in a third switching position,

18 is a view according to FIGS. 15 to 17 with the valve element in a fourth switching position and FIG. 19 is a schematic view of the hydraulic structure of a heating system with a centrifugal pump assembly according to FIGS

18th

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

The centrifugal pump assembly according to both embodiments of the invention has a motor housing 2, in which an electric drive motor is arranged. This has in known manner a stator 4 and a rotor 6, which is arranged on a rotor shaft 8. The rotor 6 rotates in a rotor space, which is separated from the stator space in which the stator 4 is arranged by a split tube or a split pot 10. That is, it is a wet-running electric drive motor. At one axial end, the motor housing 2 is connected to a pump housing 12, in which a rotatably connected to the rotor shaft 8 impeller 14 rotates.

At the pump housing 12 opposite axial end of the motor housing 2, an electronics housing 16 is arranged, which controls an electronic control device 17 for controlling the electric drive motor in the pump housing 2 includes. The electronics housing 1 6 could be arranged in a corresponding manner also on another side of the stator housing 2.

[26] In addition, a movable valve element 18 is arranged in the pump housing 12. This valve element 18 is rotatably mounted on an axis 20 in the interior of the pump housing 12, in such a way that the axis of rotation of the valve element 18 is aligned with the axis of rotation X of the impeller 14. The axis 20 is rotatably fixed to the bottom of the pump housing 12. The valve element 18 is not only rotatable about the axis 20, but by a certain amount in the longitudinal direction X movable. In one direction, this linear mobility is limited by the pump housing 12, against which the valve element 18 abuts with its outer circumference.

The valve element 18 separates in the pump housing 12 a suction chamber 24 from a pressure chamber 26. In the pressure chamber 26 rotates the impeller 14. The pressure chamber 26 is connected to the pressure port or discharge nozzle 27 of the centrifugal pump assembly, which forms the outlet of the centrifugal pump assembly.

[28] In both embodiments shown, a mechanical coupling between the drive motor and the valve element is provided, wherein in these embodiments, the drive motor of the control device 1 7 in two different operating modes or operating modes can be controlled. In a first operating mode, which corresponds to the normal operation of the circulating pump unit, the drive motor rotates in a conventional manner with a desired speed, which can be set in particular by the control device 17. In the second operating mode, the drive motor is activated in open-loop mode, so that the rotor can be rotated stepwise in individual predetermined by the controller 17 angular steps, which are smaller than 360 °, can be rotated. Thus, the drive motor in the manner of a stepping motor can be moved in individual steps, which is used in these embodiments, the valve element targeted to move in small angular increments in a defined position, as will be described below.

In the first embodiment according to FIGS. 1 to 9, a mixing valve is integrated in the pump housing 2, as can be used, for example, to set the temperature for underfloor heating.

[30] The motor housing 2 with the electronics housing 16 corresponds to the embodiment described above. The pump housing 12 has, in addition to the pressure port 27, two suction-side ports 32 and 34 which open at the bottom of the pump housing 12 in inputs 28 and 30, which are located in a plane transverse to the axis of rotation X.

The valve element 18 is drum-shaped and consists of a pot-shaped lower part 76, which is closed on its side facing the impeller 14 by a cover 78. In the central region of the lid 78, a suction opening 36 is formed. The suction opening 36 is in engagement with the suction mouth 38 of the impeller 14. The valve element 18 is rotatably mounted on an axle 20, which is arranged in the bottom of the pump housing 12. The axis of rotation of the valve element 18 corresponds to the axis of rotation X of the rotor shaft 8. The valve element 18 is also axially displaceable along the axis X and is pressed by a spring 48 in the rest position shown in Fig. 5, in which the valve element 18 in a dissolved Position is in which the lower part 76 is not applied to the bottom of the pump housing 12, so that the valve element 18 is substantially free to the axis 20 is rotatable. As an axial stop acting in the released position, the front end of the rotor shaft 8, which is designed as a coupling 108. The clutch 108 engages with a counter-coupling 1 10, which is arranged non-rotatably on the valve element 18 in engagement. The coupling 108 has tapered coupling surfaces, which essentially describe a sawtooth profile along a circumferential line in such a way that torque transmission from the coupling 108 to the counter-coupling 110 is possible only in one direction of rotation, namely in the direction of rotation A in FIG. 3. In the opposite direction of rotation B, however, the clutch slips through, resulting in an axial movement of the valve element 18. The direction of rotation B is the direction of rotation in which the pump unit is driven in normal operation. The direction of rotation A, however, is used for targeted adjustment of the valve element 18. That is, here is a direction of rotation dependent coupling is formed. In addition, however, the counter-coupling 1 10 of the clutch 108 by the pressure in the pressure chamber 26 is disengaged. If the pressure in the pressure chamber 26 increases, a pressure force acting on the cover 78 which opposes and exceeds the spring force of the spring 48, so that the valve element 18 is pressed into the abutting position, which is shown in Fig. 4. In this, the lower part 76 rests on the bottom side of the pump housing 12, so that on the one hand the valve element 18 is frictionally held and on the other hand a tight contact is achieved, which seals the pressure and the suction side against each other in the manner described below.

The suction port 32 opens at the inlet 28 and the suction port 34 opens at the inlet 30 in the bottom of the pump housing 12 in the interior, that is, the suction chamber 24 into it. The lower part 76 of the valve element 18 has in its bottom a bow-shaped opening 1 12, which extends substantially over 90 °. Fig. 6 shows a first switching position, in which the opening 1 12th only the input 30 is covered, so that a flow path is given only from the suction port 34 to the suction port 36 and thus to the suction port 38 of the impeller 14. The second input 28 is sealed by the voltage applied in its peripheral region bottom of the valve element 18. Fig. 8 shows the second switching position in which the opening 1 12 covers only the input 28, while the input 30 is closed. In this switching position, only one flow path from the suction port 32 to the suction mouth 38 is opened. Fig. 7 now shows an intermediate position in which the opening 1 12 covers both inputs 28 and 30, wherein the input 30 is only partially released. By changing the degree of release of the port 30, a mixing ratio between the flows from the inputs 28 and 30 can be changed. About the stepwise adjustment of the rotor shaft 8 and the valve element 18 can be adjusted in small steps to change the mixing ratio.

[33] Such functionality may be used, for example, in a hydraulic system as shown in FIG. There, the centrifugal pump assembly with the integrated valve, as described above, characterized by the dashed line 1 is marked. The hydraulic circuit has a heat source 1 14 in the form of, for example, a gas boiler, whose output opens into, for example, the suction port 34 of the pump housing 12. In this example, a floor heating circuit 1 1 6 connects to the pressure port 27 of the centrifugal pump assembly 1, whose return is connected both to the input of the heat source 1 14 and to the suction port 32 of the centrifugal pump unit. Via a second circulating pump unit 1 18, a further heating circuit 120 can be supplied with a heat carrier, which has the output-side temperature of the heat source 1 14. The floor heating circuit 1 1 6, however, can be regulated in its flow temperature in such a way that cold water from the return to the hot water on the output side of the heat 14 is mixed by changing the opening ratios of the inputs 28 and 30 in the manner described above, the mixing ratio can be changed by rotation of the valve element 18h. [34] The second embodiment according to FIGS. 10 to 19 shows a centrifugal pump unit which, in addition to the above-described mixer functionality, also has a switching functionality for the additional supply of a secondary heat exchanger for heating service water. [35] The bearing and the drive of the valve element 18i in this embodiment are the same as in the ninth embodiment. In contrast to the valve element 18, the valve element 18i in addition to the opening 1 12 a passage 122 which extends from an opening 124 in the lid 78i to an opening in the bottom of the lower part 76i and thus connects the two axial ends of the valve element 18i together , Furthermore, in the valve element 18i, an arcuate bypass opening 126, which is open only to the underside, that is, to the bottom of the lower part 76i and thus to the suction chamber 24, is formed, which is closed to the pressure chamber 26 by the cover 78i.

[36] The pump housing 12 has, in addition to the pressure port 27 and the two previously described suction ports 34 and 32, a further port 128. The connection 128 opens into an inlet 130 in the bottom of the circulating pump unit 12 in addition to the inputs 28 and 30 into the suction chamber 24. The various switching positions are explained with reference to FIGS. 15 to 18, wherein in these figures the cover 78i of the valve element 18i is shown partially open to illustrate the position of the underlying openings. 15 shows a first switching position in which the opening tion 1 12 the input 30 is opposite, so that a flow connection from the suction port 34 to the suction port 38 of the impeller 14 is made. In the switching position according to FIG. 16, the opening 12 lies above the inlet 130, so that a flow connection is created from the connection 128 to the suction opening 36 and via this into the suction mouth 38 of the impeller 14. In a further switching position, which shows Fig. 17, the opening 1 12 is located above the input 30, so that in turn a flow connection from the suction port 34 is given to the suction port 38 of the impeller 14. At the same time, a partial overlap of the opening 124 and the through hole 122 with the input 28 takes place, so that a connection between the pressure chamber 26 and the suction port 32 is made, which acts as a pressure port. At the same time, the bypass opening 126 simultaneously covers the input 130 and a part of the input 28, so that a connection is also provided from the terminal 128 via the input 130, the bypass opening 126 and the input 28 to the terminal 32.

[37] FIG. 18 shows a fourth switching position in which the through-channel 122 completely covers the input 28, so that the connection 32 is connected to the pressure space 26 via the through-channel 122 and the opening 124. At the same time, the bridging opening 126 only covers the entrance 130. The opening 12 also covers the entrance 30.

[38] Such a centrifugal pump unit can be used, for example, in a heating system as shown in FIG. There, the dashed line bounds the centrifugal pump unit 1, as has just been described with reference to FIGS. 10 to 18. The heating system in turn has a primary heat exchanger or a heat source 1 14, which may be, for example, a gas boiler. On the output side, the flow path runs in a first heating circuit 120, which may be formed for example by conventional radiators or radiators. At the same time, a flow path branches off to a secondary heat exchanger 56 for heating service water. The heating system further comprises a floor heating circuit 1 1 6. The returns of the heating circuit 120 and the floor heating circuit 1 1 6 open into the suction port 34 on the pump housing 12. The return from the secondary heat exchanger 56 opens into the port 128, which, as will be described below, offers two functionalities. The connection 32 of the pump housing 12 is connected to the flow of the floor heating circuit 1 1 6.

[39] When the valve element 18i is in the first switching position shown in FIG. 15, the impeller 14 conveys liquid from the suction port 34 via the pressure port 27 through the heat source 140 and the heating circuit 120 and back to the suction port 34 If the valve element 18i in the second switching position, which is shown in FIG. 16, the system is switched to service water operation, in this state, the pump unit or the impeller 14 delivers fluid from the port 128, which serves as a suction port, through the pressure port 27 , Via the heat source 1 14 through the secondary heat exchanger 56 and back to the terminal 128. If the valve element 18i in the third switching position, which is shown in Fig. 1 7, in addition the floor heating circuit 1 1 6 is supplied. Via the suction connection 34, the water flows into the suction mouth 38 of the impeller 14 and is conveyed via the pressure connection 27 via the heat source 14 in the manner described by the first heating circuit 120. At the same time, the liquid emerges on the output side of the impeller 14 from the pressure chamber 26 into the opening 124 and through the through-passage 122 and thus flows to the terminal 32 and via this into the underfloor heating circuit 16. [40] In the switching position shown in FIG. 17, liquid flows via the connection 128 and the inlet 130 into the connection 32 at the same time via the bridging opening 126. That is to say, water flows through the heat exchanger 14 through the secondary heat exchanger 26 and the connection 128 to the terminal 32. Since substantially no heat is removed from the secondary heat exchanger 56 in this heating operation, hot water is added to the connection 32 in addition to the cold water flowing from the pressure space 26 via the passage 122 to the connection 32. By varying the degree of opening via the valve position 18i, the amount of hot water mixed in at port 32 can be varied. Fig. 18 shows a switching position in which the admixture is switched off and the terminal 32 is exclusively in communication with the pressure chamber 26 directly. In this condition, the water in the floor circle 1 1 6 is conveyed in a circle without heat supply. It can be seen that by changing the switching positions of the valve element 18i in this embodiment, both a switching between heating and domestic water heating can be achieved and at the same time the supply of two heating circuits with different temperatures, namely a first heating circuit 120 with the output temperature of the heat source. 1 14 and a Fußbodenheizkreises 1 16 with a reduced over a mixing function temperature.

[41] Due to the fact that the clutch 108 and the counter-clutch 110 are disengaged in the first operating mode during normal operation of the circulating pump unit when the impeller 14 delivers fluid, the problem arises when changing to the second operating mode. which requires a reversal of rotation to bring the rotor 6 and the valve element 18, 18i again in a defined orientation with respect to their angular positions. The valve element 18, 18i should be held substantially in the position in which it was when the pump unit was last selected by the control device 17 by the second mode has changed to the first operating mode. At the same time, the controller 17 is aware of the position of the rotor 6, and the controller 17 is configured to store the rotor position. However, since it can not be completely ruled out that the valve element 18, 18i may have shifted by a small amount, the rotor 6 is preferably initially positioned in the second operating mode when the control unit 17 is changed again so that the control device 17 Rotor 6 by appropriate control of the stator 4 is not quite up to the stored angular position rotates, but preferably shortly before stops. Ie. In a first step, when the second operating mode is started, the rotor 6 is rotated into a previously stored angular position or into an angular position which is slightly ahead of the last stored angular position in the direction of rotation. Subsequently, the rotor can be rotated together with the valve element 18, 18i into a desired second angular position, wherein the control device 17 controls the stator 6 in such a way that the rotor 6 rotates exactly at the desired angle in this second mode of operation. During this rotation, the counter coupling 1 10 is taken over the clutch 108, so that the valve element 18, 18i is then rotated to the desired angular position. In this, the rotor 6 is stopped and the controller 17 switches back to the first mode or the first mode of operation and starts the rotor 6 in the opposite direction of rotation, so that the clutch 108 of the counter-clutch 1 10 can disengage and incidentally by the axial displacement of the valve element 18, 18i by the pressure generated in the pressure chamber 26, the clutch 108 and the counter-coupling 1 10 completely disengage and the valve element 18, 18i is held by engagement with the bottom of the pump housing 12 in the switching position reached. The coupling 108 has two slopes or wedge surfaces 132 which extend from two end edges 134, which in Substantially in the diametrical direction with respect to the axis of rotation X run. On the side of the end edges 134 facing away from the wedge surfaces 132, engagement surfaces 136 extend, which extend essentially in a plane which is spanned by the rotation axis X and a diameter line to this rotation axis X. The mating coupling 10 has a web-shaped projection 138 extending in the diameter direction with respect to the axis of rotation X, which protrudes in the axial direction and has two substantially mutually parallel side surfaces, which in turn extend in planes which are essentially of the diameter line and the axis of rotation X. or be clamped to these parallel axes. The side surfaces of the projection 138 engage the engagement surfaces 136 when the clutch is engaged. In the reverse direction of rotation D, the projection 138 slides on the wedge surfaces 137 under axial displacement. In this embodiment of the coupling 108 and the counter-coupling 1 10 there are exactly two offset by 180 ° to each other positions in which the rotor 6 and the valve element 18, 18i can be coupled together.

In the embodiments described above, the pump housing 12 is integrally formed. However, it is to be understood that the pump housing can also be designed in several parts. In particular, a separate from the pump housing valve housing may be provided, in which the valve element described is arranged, while in the pump housing, only the impeller is arranged. Such a valve and pump housing can be connected to each other in a suitable manner. LIST OF REFERENCE NUMBERS

1 centrifugal pump unit

2 motor housing

4 stator

6 rotor

8 rotor shaft

10 can

12 pump housings

14 impeller

1 6 electronics housing

1 7 control device

18 1 8i valve element

20 axis

24 suction chamber

26 pressure room

27 pressure connection

28, 30 inputs

32, 34 suction connections

38 suction mouth

48 spring

76 76i lower part

78, 78i lid

108 clutch

1 10 counter coupling

1 12 opening

1 14 heat source

1 1 6 Floor heating circuit

1 18 Circulation pump unit

120 heating circuit

122 passageway

124 opening 126 Bypass opening

128 connection

130 entrance

132 wedge surfaces

134 front edges

136 engagement surfaces

138 advantage

X axis of rotation

A, B directions of rotation

Claims

claims

Pump unit with an electric drive motor, at least one of the electric drive motor rotatably driven impeller (14) and a control device (17) which drives the drive motor,

characterized in that

the control device (17) is designed such that it drives the drive motor optionally in at least a first or a 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 for Generating a flow and pressure on the impeller continuously rotates, and in the second mode, the drive motor of the control device (1 7) is controlled such that the rotor (6) of the drive motor stepwise in at least one selected angular step of preferably less than 360 ° to achieve a certain Angular position is moved on.

Pump unit according to claim 1, characterized in that the control device (17) is designed such that the drive motor rotates in the first operating mode with a higher angular velocity than in the second operating mode.

Pump unit according to claim 1 or 2, characterized in that the control device (17) is designed such that in the first mode of operation of the drive motor is adjustable in its speed and preferably adjustable.

Pump unit according to one of the preceding claims, characterized in that the control device (17) is designed such that the drive motor in the second mode is controlled by the control device (1 7) in open loop (open-loop operation).

Pump unit according to one of the preceding claims, characterized in that the control device (17) is designed such that in the second operating mode, the drive motor is driven by the control device (17) with a frequency less than 10 Hz and / or the motor current of the two- to four times the nominal current for which the drive motor is designed.

Pump unit according to one of the preceding claims, characterized in that the control device (17) has a frequency converter.

Pump unit according to one of the preceding claims, characterized in that the control device (17) is designed such that the number and / or the size of the individual angular steps in which the rotor (6) is moved in the second mode, is selectable.

Pump unit according to one of the preceding claims, characterized in that the control device (17) is designed such that it drives the drive motor such that the direction of rotation (A) in the second mode is opposite to the direction of rotation (B) in the first mode.

9. Pump unit according to one of the preceding claims, characterized in that the rotor (6) of the drive motor in addition to the at least one impeller (14) via a detachable Coupling (108, 1 10) with at least one further movable member (18, 18i) is coupled.

Pump unit according to claim 9, characterized in that the coupling (108, 1 10) is such Drehrichtungsabhangig solvable that in a first rotational direction (A) is engaged and in the opposite second direction of rotation (B) is released.

Pump unit according to claim 9 or 10, characterized in that the coupling (108) is formed at a front end of a rotor shaft (8) of the rotor and in particular has a sawtooth profile.

12. Pump unit according to one of claims 9 to 1 1, characterized in that the at least one further movable member is a valve element (18; 18i), wherein the valve element (18; 18i) is preferably part of a mixing and / or change-over valve. 13. Pump unit according to claim 12, characterized in that the valve element (18; 18i) is designed and arranged such that it is rotatably movable between at least two switching positions, wherein a rotation axis (X) of the valve element (18; 18i) is preferably aligned with Rotary axis (X) of the drive motor is arranged.

Pump unit according to claim 12 or 13, characterized in that the valve element (18; 18i) is arranged in the pump unit such that it has a pressure surface (78; 78i) on which an output side of the at least one impeller (14) prevails pressure and the valve element (18; 18i) in a direction transverse to the pressure surface (78; 78i) between a Investment position in which it bears against at least one contact surface, and a dissolved position in which it is detached or spaced from the contact surface is movably mounted, wherein preferably a return element (48) is provided, which generates a restoring force, which one from the pressure at the

Pressure surface (78; 78i) is oppositely generated pressure force generated.

15. Pump unit according to claim 14, characterized in that the contact surface is a sealing surface.

Pump unit according to claim 14 or 15, characterized in that a movement path (X) between the abutment position and the disengaged position is different from a movement path between the at least two switching positions of the valve element (18; 18i).

Pump unit according to one of the preceding claims, characterized in that it is designed as a circulating pump unit and in particular as a Heizungsumwälzpumpenaggregat.