PUMP ASSEMBLY

Abstract

A pump assembly includes an electrical drive motor, at least one impeller (14) which is rotatingly driven by the electrical drive motor as well as a control device (17) which activates the drive motor. The control device (17) is configured such that the control device (17) selectively activates the drive motor in at least one first or a second operating mode. In a first operating mode, the drive motor is activated by the control device (17) such that a rotor (6) of the drive motor continuously rotates. In the second operating mode the drive motor is controlled by the control device (17) such that the rotor (6) of the drive motor is moved further stepwise manner in at least one selected angular step of preferably smaller than 360.

Claims

1. A pump assembly comprising: an electrical drive motor; at least one impeller which is rotatingly driven by the electrical drive motor; and a control device which activates the drive motor, wherein the control device is configured to selectively activate 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 activated by the control device such that a rotor of the drive motor continuously rotates for producing a flow and a pressure at the impeller, and in the second operating mode, the drive motor is controlled by the control device such that the rotor of the drive motor is moved further stepwise in at least one selected angular step for reaching a certain angular position.

2. A pump assembly according to claim 1, wherein the control device is configured such that the drive motor rotates at higher angular speed in the first operating mode than in the second operating mode.

3. A pump assembly according to claim 1, wherein the control device is configured such that in the first operating mode, the drive motor in is speed adjustable and closed-loop controllable.

4. A pump assembly according to claim 1, wherein the control device is configured such that in the second operating mode, the drive motor is controlled by the control device with an open-loop.

5. A pump assembly according to claim 1, wherein the control device is configured such that in the second operating mode, the drive motor is activated by the control device at a frequency <10 Hertz and/or the motor current corresponds to twice to fourfold the rated amperage, for which the drive motor is designed.

6. A pump assembly according to claim 1, wherein the control device comprises a frequency converter.

7. A pump assembly according to claim 1, wherein the control device is configured such that a number and/or a size of the individual angular steps, in which the rotor is moved in the second operating mode, is selectable.

8. A pump assembly according to claim 1, wherein the control device is configured such that the control device activates the drive motor such that a drive motor rotation direction in the second operating mode is opposite to a drive motor rotation direction in the first operating mode.

9. A pump assembly according to claim 1, wherein the rotor of the drive motor, in addition to being coupled to the at least one impeller, is coupled to at least one further movable component via a releasable coupling.

10. A pump assembly according to claim 9, wherein the releasable coupling is rotation-direction dependently releasable such that in a first rotation direction the releasable coupling is engaged and in the opposite second rotation direction the releasable coupling is released.

11. A pump assembly according to claim 9, wherein the releasable coupling is formed at a face end of a rotor shaft of the rotor and has a saw-tooth profile.

12. A pump assembly according to claim 9, wherein the at least one further movable component is a valve element part of a mixing valve and/or switch-over valve.

13. A pump assembly according to claim 12, wherein: the valve element is configured and arranged such that the valve element is rotatingly movable between at least two switching positions; and a rotation axis of the valve element is arranged aligned to a rotation of the drive motor.

14. A pump assembly according to claim 12, wherein the valve element is arranged in the pump assembly such that the valve element comprises a pressure surface, upon which a pressure prevailing at the outlet side of the at least one impeller acts, and the valve element is movably mounted in a direction transverse to the pressure surface between a bearing position, in which the valve element bears on at least one contact surface, and a released position, in which the valve element is released or distanced to the contact surface, wherein a restoring element is provided, said restoring element producing a restoring force which is directed oppositely to the pressing force which is produced by the pressure on the pressure surface.

15. A pump assembly according to claim 14, wherein the contact surface is a sealing surface.

16. A pump assembly according to claim 14, wherein a movement path between the bearing position and a released position is different to a movement path between the at least two switching positions of the valve element.

17. A pump assembly according to claim 1, wherein the pump assembly is configured as a circulation pump assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the drawings:

[0024] FIG. 1 is an exploded view of the centrifugal pump assembly according to a first embodiment of the invention;

[0025] FIG. 2 is a perspective view of the centrifugal pump assembly according to FIG. 1 with a removed pump casing and valve element;

[0026] FIG. 3 is a perspective view of the motor shaft of the centrifugal pump assembly according to FIGS. 1 and 2 as well as of the coupling part of the valve element;

[0027] FIG. 4 is a sectioned view of the centrifugal pump assembly according to FIG. 1 with the valve element in a first position;

[0028] FIG. 5 is a sectioned view according to FIG. 4 with the valve element in a second position;

[0029] FIG. 6 is a plan view upon the opened pump casing of the centrifugal pump assembly according to FIGS. 1 to 3 with the valve element in a first switching position;

[0030] FIG. 7 is a view according to FIG. 6 with the valve element in a second switching position;

[0031] FIG. 8 is a view according to FIGS. 6 and 7 with the valve element in a third switching position;

[0032] FIG. 9 is a schematic view of the hydraulic construction of a heating facility with a centrifugal pump assembly according to FIGS. 1 to 8;

[0033] FIG. 10 is an exploded view of a centrifugal pump assembly according to a second embodiment of the invention;

[0034] FIG. 11 is a perspective view of the opened valve element of the centrifugal pump assembly according to FIG. 10;

[0035] FIG. 12 is a perspective view of the closed valve element according to FIG. 11;

[0036] FIG. 13 is a sectioned view of the centrifugal pump assembly according to FIG. 10 with the valve element in a first position;

[0037] FIG. 14 is a sectioned view according to FIG. 13 with the valve element in a second position;

[0038] FIG. 15 is a plan view upon the opened pump casing of the centrifugal pump assembly according to FIGS. 10 to 14 with the valve element in a first switching position;

[0039] FIG. 16 is a view according to FIG. 15 with the valve element in a second switching position;

[0040] FIG. 17 is a view according to FIGS. 15 and 16 with the valve element in a third switching position;

[0041] FIG. 18 is a view according to FIGS. 15 to 17 with the valve element in a fourth switching position; and

[0042] FIG. 19 is a schematic view of the hydraulic construction of a heating facility with a centrifugal pump assembly according to FIGS. 10 to 18.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0043] Referring to the drawings, the embodiment examples of the centrifugal pump assembly according to the invention which are described in the following description relate to applications in heating systems and/or air conditioning systems, in which a fluid heat transfer medium, in particular water is circulated by the centrifugal pump assembly.

[0044] The centrifugal pump assembly according to both embodiments of the invention comprises a motor casing 2, in which an electrical drive motor is arranged. This in the known manner comprises a stator 4 as well as 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 way of a can or a canned pot 10. This means that here it is the case of a wet-running electrical drive motor. The motor casing 2 is connected to a pump casing 12 at an axial end, in which pump casing an impeller 14 which is connected to the rotor shaft 8 in a rotationally fixed manner rotates.

[0045] An electronics casing 16 which contains control electronics or a control device 17 for the activation of the electrical drive motor in the pump casing 2 is arranged at the axial end of the motor casing 2 which is opposite to the pump casing 12. The electronics casing 16 could also be arranged at another side of the pump casing 2 in a corresponding manner.

[0046] A movable valve element 18 is moreover arranged in the pump casing 12. This valve element 18 is rotatably mounted on a pivot 20 in the inside of the pump casing 12, and specifically such that the rotation axis of the valve element 18 is aligned with the rotation axis X of the impeller 14. The pivot 20 is fixed to the base of the pump casing 12 in a rotationally fixed manner. The valve element 18 is not only rotatable about the pivot 20 but is movable in the longitudinal direction X by a certain amount. This linear movability is limited in one direction by way of the pump casing 12, upon which the valve element 18 butts with its outer periphery.

[0047] In the pump casing 12, the valve element 18 separates a suction chamber 24 from a delivery chamber 26. The impeller 14 rotates in the delivery chamber 26. The delivery chamber 26 is connected to the delivery branch 27 of the centrifugal pump assembly which forms the outlet of the centrifugal pump assembly.

[0048] With regard to both represented embodiments, a mechanical coupling is likewise provided between the drive motor and the valve element, wherein concerning these embodiments, the drive motor can be activated in two different operational types or modes by way of the control device 17. In a first operating mode which corresponds to the normal operation of the circulation pump assembly, the drive motor rotates in the conventional manner at a desired speed which can be adjusted, in particular by the control device 17. In the second operating mode, the drive motor is activated (controlled) in open loop operation, so that the rotor can be rotated stepwise in individual angular steps which are smaller than 360 and which are set by the control device 17. The drive motor can therefore be moved in individual steps in the manner of a stepper motor, which concerning these embodiment examples is used in order to move the valve element in small angular steps into a defined position in a targeted manner, as is described hereinafter.

[0049] With regard to the first embodiment according to FIGS. 1 to 9, a mixing valve as can be used for example for temperature adjustment for a floor heating is integrated in the pump casing 2.

[0050] The motor casing 2 with the electronics casing 16 corresponds to the previously described embodiment. The pump casing 12, apart from the delivery branch 27 (delivery branch connection or simply delivery connection), comprises two suction-side branches 32 and 34 which run out into inlets 28 and 30 on the base of the pump casing 12, said inlets being situated in a plane transverse to the rotation axis (X).

[0051] The valve element 18 is configured in a drum-like manner and consists of a pot-like lower part 76 which at its side which faces the impeller 14 is closed by a cover 78. A suction opening 36 is formed in the central region of the cover 78. The suction opening 36 is engaged with the suction port 38 of the impeller 14. The valve element 18 is rotatably mounted on a pivot 20 which is arranged in the base of the pump casing 12. Here, the rotation axis of the valve element 18 corresponds to the rotation axis X of the rotor shaft 8. The valve element 18 is likewise axially displaceable along the axis X and is pressed by a spring 48 into the idle position which is shown in FIG. 5 and in which the valve element 18 is located in released position, in which the lower part 76 does not bear on the base of the pump casing 12, so that the valve element 18 is essentially freely rotatable about the pivot 20. In the released position, the face end of the rotor shaft 8 which is configured as a coupling 108 functions 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 comprises inclined (beveled) coupling surfaces which along a peripheral line essentially describe a saw-toothed profile in a manner such that a torque transmission from the coupling 108 onto the counter coupling 110 is only possible in one rotation direction, specifically in the rotation direction A in FIG. 3. In contrast, the coupling slips through in the opposite rotation direction B, wherein an axial movement of the valve element 18 occurs. The rotation direction B is that rotation direction, in which the pump assembly is driven in normal operation. In contrast, the rotation direction A is used for the targeted actuation of the valve element 18. This means that a rotation-direction-dependent coupling is formed here. However, the counter-coupling 110 additionally disengages from the coupling 108 due to the pressure in the delivery chamber 26. If the pressure in the delivery chamber 26 increases, then a pressing force which is opposed to the spring force of the spring 48 and which exceeds this acts upon the cover 78, so that the valve element 18 is pressed into the bearing position as is shown in FIG. 4. In this position, the lower part 76 bears on the base side of the pump casing 12, so that on the one hand the valve element 18 is non-positively held and on the other hand a sealed bearing contact is achieved, said contact sealing the delivery side and the suction side with respect to one another in the subsequently described manner.

[0052] The suction branch 32 runs out at an inlet 28 and the suction branch 34 at an inlet 30, in the base of the pump casing 12 into the interior of this, which is to say into the suction chamber 24. The lower part 76 of the valve element 18 in its base comprises an arched opening 112 which extends essentially over 90. FIG. 6 shows a first switching position, in which the opening 112 only overlaps the inlet 30, so that a flow path is only given from the suction branch 34 to the suction opening 36 and therefore to the suction port 38 of the impeller 14. The second inlet 28 is sealingly closed by the base of the valve element 18 which bears in the peripheral region of this second inlet. FIG. 8 shows the second switching position, in which the opening 112 only overlaps the inlet 28, whilst the inlet 30 is closed. In this switching position, only a flow path from the suction branch 32 to the suction port 38 is opened. FIG. 7 now shows an intermediate position, in which the opening 112 overlaps both inlets 28 and 30, wherein the inlet 30 is only partly released. A mixing ratio between the flows from the inlets 28 and 30 can be changed by way of changing the degree of release of the branch 30. The valve element 18 can also be actuated or adjusted in small steps via the stepwise actuation of the rotor shaft 8, in order to change the mixing ratio.

[0053] Such a functionality can be applied for example in a hydraulic system as is shown in FIG. 9. There, the centrifugal pump assembly with the integrated valve as has been described above is characterized by the dashed line 1. The hydraulic circuit comprises a heat source 114 in the form of a gas heating boiler for example, the outlet of which running out for example into the suction branch 34 of the pump casing 12. In this example, a floor heating circuit 116 whose return is connected to the inlet of the heat source 114 as well as to the suction branch 32 of the centrifugal pump assembly 114 connects onto the delivery branch 27 of the centrifugal pump assembly 1. A further heating circuit 120 can be supplied with a heat transfer medium which has the outlet-side temperature of the heat source 114, via a second centrifugal pump assembly 118. The floor heating circuit 116 in contrast can be regulated in its feed temperature in a manner such that cold water from the return is admixed to the hot water at the outlet side of the heat source 114, wherein the mixing ratio can be changed by way of changing the opening ratios of the inlets 28 and 30 in the manner described above by way of rotating the valve element 18.

[0054] The second embodiment example according to FIGS. 10 to 19 shows a centrifugal pump assembly which additionally to the previously described mixing function yet comprises a switch-over functionality for the additional supply of a secondary heat exchanger for the heating of service water.

[0055] Concerning this embodiment, the mounting and drive of the valve element 18i is effected just as with the ninth embodiment. In contrast to the valve element 18, the valve element 18i additionally to the opening 112 comprises a through-channel 122 which extends from an opening 124 in the cover 78i to an opening in the base of the lower part 76i and therefore connects the two axial ends of the valve element 18i to one another. An arched bridging opening 126 is moreover yet formed in the valve element 18i and this opening is closed to the delivery chamber 28 by the cover 78i and is only open to the lower side, which is to say to the base of the lower part 76i and thus to the suction chamber 24.

[0056] Apart from the delivery branch 27 and both previously described suction branches 34 and 32, the pump casing 12 comprises a further branch 128. The branch 128 runs out in an inlet 130 in the base of the centrifugal pump assembly 12 additionally to the inlets 28 and 30, into the suction chamber 24. The various switching positions are explained by way of FIGS. 15 to 18, wherein the cover 78i of the valve element 18i is shown in a partly opened manner in these figures, in order to clarify the position of the openings which lie therebelow. FIG. 15 shows a first switching position, in which the opening 112 lies opposite the inlet 30, so that a flow connection from the suction branch 34 to the suction port 38 of the impeller 14 is created. In the switching position according to FIG. 16, the opening 112 lies over the inlet 130, so that a flow connection from the branch 128 to the suction opening 36 and via this into the suction port 38 of the impeller 14 is created. In a further switching position which is shown in FIG. 17, the opening 112 lies over the inlet 30, so that again a flow connection from the suction branch 34 to the suction port 38 of the impeller 14 is given. A partial overlapping of the opening 124 and of the through-hole 122 with the inlet 28 simultaneously takes place, so that a connection between the delivery chamber 26 and the suction port 32 which functions here as a delivery branch is created. The bridging opening 126 simultaneously overlaps the inlet 130 and a part of the inlet 28, so that a connection from the branch 128 to the branch 32 is likewise created via the inlet 130, the bridging opening 126 and the inlet 28.

[0057] FIG. 18 shows a fourth switching position, in which the through-channel 122 completely overlaps the inlet 28, so that the branch 32 is connected to the delivery chamber 26 via the through-channel 122 and the opening 124. Simultaneously, the bridging opening 126 continues to cover only the inlet 130. The opening 112 continues to cover the inlet 30.

[0058] Such a centrifugal pump assembly can be applied for example in a heating system as is shown in FIG. 19. Here, the dashed line delimits the centrifugal pump assembly 1, as has just been described by way of FIGS. 10 to 18. The heating system again comprises a primary heat exchanger or a heat source 114 which for example can be gas heating boiler. At the outlet side, the flow path runs into a first heating circuit 120 which can be formed for example by way of conventional radiators. A flow path simultaneously branches to a secondary heat exchanger 56 for heating service water. The heating system moreover comprises a floor heating circuit 116. The returns of the heating circuit 120 and of the floor heating circuit 116 run out into the suction branch 34 on the pump casing 12. The return from the secondary heat exchanger 56 runs out into the branch 128 which provides two functionalities as is described hereinafter. The branch 32 of the pump casing 12 is connected to the feed of the floor heating circuit 116.

[0059] When the valve element 18i is located in the first switching position represented in FIG. 15, the impeller 14 delivers fluid from the suction branch 34 via the delivery branch 27 through the heat source 140 and the heating circuit 120 and back to the suction branch 34. If the valve element 18i is located in the second switching position which is shown in FIG. 16, the facility is switched over to service water operation and in this condition the pump assembly or the impeller 14 delivers fluid from the branch 128 which serves as a suction branch, through the delivery branch 27, via the heat source 114 through the secondary heat exchanger 56 and back to the branch 128. The floor heating circuit 116 is additionally supplied if the valve element 18i is located in the third switching position which is shown in FIG. 17. The water flows into the suction port 38 of the impeller 14 via the suction branch 34 and is delivered via the delivery branch 27 through the first heating circuit 120 via the heat source 114 in the described manner. The fluid at the outlet side of the impeller 14 simultaneously exits the delivery chamber 26 into the opening 124 and through the through-channel 122 and thus flows to the branch 32 and via this into the floor heating circuit 116.

[0060] Fluid simultaneously flows via the bridging opening 126 into the branch 32 via the branch 128 and the inlet 130, in the switching position which is shown in FIG. 17. This means that here water flows via the heat source 114 through the secondary heat exchanger 26 and the branch 128 to the branch 32. Since essentially no heat is taken at the secondary heat exchanger 56 in this heating operation, hot water is admixed to the branch 32 additionally to the cold water which flows out of the delivery chamber 26 to the branch 32 via the through-channel 122. The quantity of the admixed warm water at the branch 32 can be varied by way of changing the degree of opening via the valve position 18i. FIG. 18 shows a switching position, in which the admixing is switched off and the branch 32 is exclusively in direct connection with the delivery chamber 26. In this condition, the water in the floor heating circuit 116 is delivered in the circuit without any supply of heat. It is to be recognized that with this embodiment, a switching between the heating and service water heating as well as simultaneously the supply of heating circuits with two different temperatures, specifically of a first heating circuit 120 with the exit temperature of the heat source 114 and of a floor heating circuit 116 with a temperature which is reduced via a mixing function, can also be achieved by way of the change of the switching positions of the valve element 18i.

[0061] The problem of bringing the rotor 6 and the valve element 18, 18i again into a defined alignment with respect to their angular positions arises on changing into the second operating mode which demands a reversal of the rotation direction. This is due to the fact that the coupling 108 and the counter coupling 110 are disengaged in the first operating mode in normal operation of the circulation pump assembly when the impeller 14 delivers fluid. The valve element 18, 18i should essentially be held essentially in the position, in which it was when the pump assembly changed the last time from the second operating mode into the first operating mode by way of the control device 17. The position of the rotor 6 is simultaneously known to the control device 17 and the control device 17 is configured such that it stores the rotor position. However, since the valve element 18, 18i having possibly been displaced by a certain amount cannot be completely ruled out, with a renewed changing into the second operating mode, a positioning of the rotor 6 is preferably firstly carried out in a manner such that by way of a suitable activation of the stator 4, the control device 17 does not rotate the rotor 6 completely into the stored angular position, but preferably stops it shortly before. I.e. in a first step, on starting operation of the second operating mode, the rotor 6 is rotated into a previously stored angular position or into an angular position which in the rotation direction lies slightly before the lastly stored angular position. The rotor together with the valve element 18, 18i can subsequently be rotated into a desired second angular position, wherein the control device 17 activates the stator 6 such that the rotor 6 in this second operating mode rotates precisely about the desired angle. With this rotation, the counter-coupling 110 is caught or driven via the coupling 108, so that the valve element 18, 18i is then rotated into the desired angular position. The rotor 6 is stopped at this angular position and the control device 17 switches back into the first operating mode or into the first operating type again and starts the rotor 6 in the opposite rotation direction, so that the coupling 108 can disengage from the counter coupling 110 and furthermore the coupling 108 and the counter coupling 110 can completely disengage due to the axial displacement of the valve element 18, 18i by way of the pressure which is produced in the delivery chamber 26, and the valve element 18, 18i can be held in the reached switching position by way of the bearing contact on the base of the pump casing 12.

[0062] The coupling 108 comprises two inclinations or wedge surfaces 132 which extend in a manner departing from two face edges 134 which run essentially in the diametrical direction with respect to the rotation axis X. Engagement surfaces 136 which run essentially in a plane which is spanned by the rotation axis X and a diameter line to this rotation axis X extend at the side of the face edges 134 which is away from the wedge surfaces 132. The counter coupling 110 comprises a web-like projection 138 which extends in the diameter direction with respect to the rotation axis X, projects in the axial direction and comprises two essentially parallel side surfaces which again extend in a plane which is essentially spanned by the diameter line and the rotation axis X or axes which are parallel to these. The side surfaces of the projection 138 come to bear on the engagement surfaces 136 when the coupling is engaged. In the opposite rotation direction D, the projection 138 slides on the wedge surfaces 137 amid axial displacement. With this embodiment of the coupling 108 and of the counter coupling 110 there are exactly two positions which are offset to one another by 180, in which the rotor 6 and the valve element 18, 18i can be coupled to one another.

[0063] The pump casing 12 is configured of one part in the previously described embodiment examples. However, it is to be understood that the pump casing can also be configured of several parts. In particular, a valve casing, in which the described valve element is arranged, can be provided separately from the pump casing, whilst only the impeller is arranged in the pump casing. Such a valve casing and pump casing can be connected to one another in a suitable manner.

[0064] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.