CENTRIFUGAL PUMP ASSEMBLY

Abstract

A centrifugal pump assembly includes an electrical drive motor (2), with at least one impeller (18) which is driven by the motor and a pump casing (6) which surrounds the impeller (18) and which includes at least one suction connection (20) and at least two delivery connections (22, 24). A rotatable valve element (30, 30, 30) is arranged in the pump casing (6). The valve element is movable between at least two switching positions, in which the flow paths through the delivery connections (22, 24) are opened to a different extent. The valve element (30, 30, 30) includes an annular wall (32) which surrounds the impeller (18) and in which at least one switching opening (48) is formed. The valve element (30, 30, 30) is rotatably mounted about a rotation axis (X), which is centric to the annular wall (32), inside of the pump casing (6).

Claims

1. A centrifugal pump assembly comprising: an electrical drive motor at least one impeller which is driven by the electrical drive motor; a pump casing which surrounds the impeller and which comprises at least one suction connection and at least two delivery connections; a rotatable valve element is arranged in the pump casing, said valve element being movable between at least two switching positions, in which the flow paths through the at least two delivery connections are opened to a different extent, wherein the valve element comprises an annular wall which surrounds the impeller and in which at least one switching opening is formed and the valve element is rotatably mounted about a rotation axis which is centric to the annular wall, in the inside of the pump casing.

2. A centrifugal pump assembly according to claim 1, wherein at least one two outlet openings are connected to the delivery connections and with which the at least one switching opening can be brought to at least partly overlap depending on the switching position of the valve element and the two outlet openings are situated in a wall of the pump casing which faces the annular wall.

3. A centrifugal pump according to claim 1, wherein the valve element in the inside of the annular wall further comprises a wall which extends transversely to the rotation axis and which surrounds a suction port of the impeller.

4. A centrifugal pump assembly according to claim 1, wherein the annular wall comprises a circular outer contour.

5. A centrifugal pump assembly according to claim 1, wherein the valve element is rotatably mounted on a stationary component in the inside of the pump casing.

6. A centrifugal pump assembly according to claim 1, wherein an edge of the at least one switching opening is completely surrounded by at least one section of the annular wall.

7. A centrifugal pump assembly according to claim 1, wherein the annular wall in an extension direction transversely to a periphery thereof extends at an angle of smaller than 90 to the rotation axis.

8. A centrifugal pump assembly according to claim 1, wherein the valve element comprises at least one movable section which is movable between a bearing position, in which the at least one moveable section frictionally bears on a contact surface in the pump casing, and a released position, in which the at least one moveable section is movable relative to the contact surface on rotation of the valve element.

9. A centrifugal pump assembly according to claim 8, wherein the valve element is configured to provide a friction-fit contact of the at least one movable section in the bearing position, whereby the valve element is held in its assumed switching position.

10. A centrifugal pump assembly according to claim 8, wherein the at least one movable section is configured as an elastic edge section of the annular wall.

11. A centrifugal pump assembly according to claim 8, wherein the valve element is completely movable in a direction transversely to its rotation direction, between a released and a bearing position.

12. A centrifugal pump assembly according to claim 8, wherein the valve element and the pump casing are configured such that in the bearing position, at least a section of the valve element bears on an inner wall of the pump casing.

13. A centrifugal pump assembly according to claim 8, wherein the valve element is configured such that a pressure which prevails in a peripheral region of the impeller acts upon the valve element such that the at least one movable section or the complete valve element is moved into the bearing position.

14. A centrifugal pump assembly according to claim 13, further comprising a force generating means which subjects the valve element or the at least one movable section to force out of the bearing position in the direction of the released position.

15. A centrifugal pump assembly according to claim 1, wherein a flow guidance element leads to the at least one switching opening and is situated on the inner periphery of the annular wall.

16. A centrifugal pump assembly according to claim 1, wherein a central region of the valve element comprises a bearing sleeve which rotatably slides on a stationary bearing bolt in the pump casing.

17. A centrifugal pump assembly according to claim 1, wherein the valve element is rotatably mounted on an inlet stub which is arranged in the pump casing and is engaged with a suction port of the impeller.

18. A centrifugal pump assembly according to claim 1, wherein a restoring element acts upon the valve element in a valve element rotation direction and is configured such that the restoring element moves the valve element (30) into a predefined initial position given a standstill of the impeller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the drawings:

[0027] FIG. 1 is a first perspective exploded view of a centrifugal pump assembly according to a first embodiment of the invention;

[0028] FIG. 2 is a perspective exploded view of the centrifugal pump assembly according to FIG. 1 from another perspective;

[0029] FIG. 3 is a circuit diagram of a heating facility with a centrifugal pump assembly according to FIGS. 1 and 2;

[0030] FIG. 4 is a plan view of the opened pump casing of a centrifugal pump assembly according to FIGS. 1 and 2 with a valve element in a first switching position;

[0031] FIG. 5 is a view according to FIG. 4 with the valve element in a second switching position;

[0032] FIG. 6 is a face-side plan view upon a centrifugal pump assembly according to FIGS. 1 and 2;

[0033] FIG. 7 is a sectioned view along the line A-A in FIG. 6 with a valve element in a released position;

[0034] FIG. 8 is a sectioned view along line B-B in FIG. 6 with the valve element in a second switching position;

[0035] FIG. 9 is a sectioned view according to FIG. 8 with the valve element in a first switching position;

[0036] FIG. 10 is a sectioned view along the line A-A in FIG. 6 with the valve element in a first switching position;

[0037] FIG. 11 is a sectioned view according to FIG. 10 with the valve element in a second switching position;

[0038] FIG. 12 is a perspective exploded view of a centrifugal pump assembly according to a second embodiment of the invention;

[0039] FIG. 13 is a perspective view into the opened pump casing of a centrifugal pump assembly according to FIG. 12;

[0040] FIG. 14 is a sectioned view of a centrifugal pump assembly according to FIG. 12;

[0041] FIG. 15 is a perspective exploded view of a centrifugal pump assembly according to a third embodiment of the invention;

[0042] FIG. 16 is a view into the opened pump casing of the centrifugal pump assembly according to FIG. 15, with a valve element in a first switching position; and

[0043] FIG. 17 is a view according to FIG. 16, with the valve element in a second switching position.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0044] Referring to the drawings, the centrifugal pump assemblies which are described hereinafter are envisaged as heating circulation pump assemblies, in particular for use in a heating facility, such as a compact heating facility which serves for heating a building as well as for heating service water. The centrifugal pump assembly according to the first embodiment of the invention comprises an electrical drive motor 2 which is arranged in a motor casing 4. The motor casing 4 is connected to a pump casing 6. An electronics housing 8 which comprises the electrical or electronic components for the control and/or regulation of the drive motor 2 is arranged at the axial end of the motor housing 4 which is away from the pump casing 6. The electrical drive motor 2 is a wet-running electrical drive motor. This means that the stator space, in which the stator 10 is arranged, is separated from a rotor space, in which the rotor 12 is arranged, by a can pot or can 14. The rotor 12 therefore rotates in the fluid to be delivered. The rotor 12 drives an impeller 18 via a rotor shaft 16 in the known manner. The impeller is arranged in the pump casing 6.

[0045] The pump casing 6 comprises a suction connection 20 as well as two delivery connections 22 and 24. The suction connection 20 runs out at the base of the pump casing 6. A suction stub (branch) or inlet stub 26 which engages into the inside of a suction port 28 of the impeller 18 is arranged there.

[0046] A pot-like valve element 30 is arranged in the inside of the pump casing 6 in a manner surrounding the impeller 18. The valve element 30 comprises a circular outer contour and extends concentrically to the rotation axis X of the drive motor 2 and of the impeller 18. The valve element 30 comprises an annular wall 32 on the outer periphery, said annular wall having a truncated-cone-shaped or conical outer contour and having an outer contour which corresponds essentially to the inner contour of the pump casing 6 in the peripheral region of the rotation axis X. The valve element 30 is completely opened at that axial end of the annular wall 32 with the larger diameter. At the opposite axial end which is smaller in diameter, the valve element 30 comprises a wall 34 which forms a base of the valve element 30. The wall 34 extends transversely to the annular wall 30 and normally to the rotation axis X. The wall 34 herein forms an annular wall which extends radially inwards departing from the annular wall 32 and surrounds a central opening 36. The inlet stub 26 extends through the opening 36. This means that the valve element 30 is placed with the opening 36 onto the inlet stub 26 and is fixed there by way of an annular securing element 38. The fixation element 38 engages from the inside into the opening 36 and is fixed on the inlet stub 26, for example in a clamped manner. The inlet stub 26 and the securing element 38 are therefore configured such that the valve element 30 is guided in the radial direction but permits a certain movement in the axial direction parallel to the longitudinal axis X.

[0047] Furthermore, a spring in the form of a corrugated spring ring 42 is arranged between the radially projecting shoulder 40 of the inlet stub 26 and the wall 34 of the valve element 30. The spring acts in the axial direction in the direction of the longitudinal axis X and presses the valve element 30 away from the shoulder 40 in the direction of the drive motor 2. In this position, as is shown in FIG. 7, the annular wall 32 as well as the wall 34 is distanced to the inner surface of the pump casing 6, so that the valve element 30 can essentially freely rotate about the inlet stub 26 which is to say about the longitudinal axis X, in the inside of the pump casing. In this state, a rotating flow which is generated by the impeller in the inside of the valve element 30 in the peripheral region of this impeller 18 can co-rotate the valve element 30 on account of the friction between the flow and the wall surfaces of the valve element 30 (inner surface of the annular wall 32 as well as the wall 34). The rotation movement is limited by a stop pin 44 which in the base of the pump casing 6 engages into an arched groove 46 which extends about the longitudinal axis X over an angle of 90. On account of the groove 46 and the stop pin 44, one succeeds in the valve element 30 being able to rotate about the longitudinal axis X between two switching positions by an angle of 90.

[0048] The switching opening 48 is formed in the periphery annular wall 32. This is configured as a hole which at its outer periphery is completely enclosed by parts of the annular wall 32. In the first switching position, the switching opening 48 can be brought to overlap with an outlet opening 50 which is connected to the delivery connection 22, so that a flow connection is created from the interior of the valve element 30 through the switching opening 48, the outlet opening 50 to the delivery connection 22. In the second switching position of the valve element 30 which is rotated by 90, the switching opening 48 is brought to overlap with an outlet opening 52 which is connected to the delivery connection 24. This means that the delivery connection 24 runs out at the outlet opening 52 into the inside of the pump casing 6. In this switching position, a flow connection is therefore given from the inside of the valve element 30 through the switching opening 48, the outlet opening 52 to the delivery connection 24. A switch-over valve, with which for example a switch-over function as is described by way of FIG. 3 can be realized is therefore realized.

[0049] FIG. 3 schematically shows the circuit diagram of a heating facility. This heating facility comprises a primary heat exchanger 54, for example a gas heater. A centrifugal pump assembly 56 is arranged at the outlet side, which is to say downstream of primary heat exchanger 54, wherein this centrifugal pump assembly can be a centrifugal pump assembly as has been described previously and is described hereinafter. A valve element 58 which can be formed by the described valve element 30 can be formed at the outlet side, which is to say at the delivery side of the circulation pump assembly 56. The flow path can be switched between a heating circuit 60 for the temperature adjustment of a building and a secondary heat exchanger 62 for heating service water, via the valve device 58, in order to either supply the heating circuit 60 or the secondary heat exchanger 62 with heat transfer medium which is heated by the primary heat exchanger 54.

[0050] The switching-over or moving of the valve element 30 is realized by control electronics 64 which are arranged in the electronics housing 8 and which activates the drive motor 2. For this, the control electronics 64 can in particular comprise a speed controller or frequency converter. One utilizes the fact that given a rapid start-up of the drive motor 2 and of the impeller 18, a pressure builds up in the peripheral region of the impeller more quickly than an annular flow which is capable of rotating the valve element 30. If for example the valve element is situated in the first switching position which is shown in FIG. 4 and in which the flow path through the delivery connection 22 is opened and the valve element 30 is to remain in this switching position on starting up the drive motor, then the dive motor 30 is rapidly accelerated so that a pressure builds up quickly in the inside of the valve element 30 and this element is pressed out of the released position which is shown in FIG. 7 into a bearing position, in which the outer side of the annular wall 32 and of the wall 34 come to frictionally bear on the inner surfaces of the pump casing 6, so that the valve element 30 is secured against rotation. The outer side of the valve element 30 therefore forms a releasable coupling with the inner side of the pump casing 6.

[0051] The impeller 18 is driven in the rotation direction A by the drive motor 2 at such a low speed that a pressure which can overcome the spring force which is produced by the spring ring 42 cannot build up in the inside of the valve element 30, in order to rotate the valve element 30 out of the first switching position which is shown in FIG. 4 into the second switching position which is shown in FIG. 5. The valve element 30 therefore remains in the released position which is shown in FIG. 7. However, after a certain time, an annular flow in the rotation direction A also builds up in the inside of the valve element 30 and this flow co-rotates the valve element 30 via frictional forces and therefore moves it into the second switching position which is shown in FIG. 5. If the speed of the drive motor 2 is subsequently increased again, then the valve element 30 in this switching position again gets into its bearing position in frictional contact with the inner surface of the pump casing 6. However, it is also possible to switch off the drive motor again in this switching position and to then bring it directly into operation in the opposite rotation direction B at such a high speed, that such a high pressure is again produced in a direct manner that the valve element 30 is moved in the axial direction X into the bearing position which is shown in FIG. 8 and cannot therefore be co-rotated in the rotation direction B by way of the flow. In order to rotate the valve element 30 into the first switching position again, the drive motor must be driven in the rotation direction B at such a speed that a flow for co-moving the valve element 30 cannot build up such a high pressure which is capable of overcoming the spring force of the spring ring 42.

[0052] FIG. 10 shows the first switching position with the valve element 30 in the bearing position. The switching opening 48 lies opposite the outlet opening 50. FIG. 11 shows the second switching position, in which a part of the annular wall 32 lies opposite the outlet opening 50, so that this is closed. Conversely, in the second switching position, as is shown in FIG. 8, the switching opening 48 lies opposite the outlet opening 52, whereas in the first switching position, as is shown in FIG. 9, a part of the annular wall 32 lies opposite the outlet opening 52 and therefore closed this. In FIGS. 8 to 11, the valve element 30 lies in its bearing position in each case, so that it bears on the inner wall of the pump casing 6 in the peripheral region of the outlet openings 50, 52 and can sealingly close these inasmuch as the annular wall 32 covers the outlet opening 50, 52.

[0053] FIGS. 12 to 14 show a second embodiment example of a centrifugal pump assembly according to the invention, concerning which the valve element merely differs from the previously described valve element 30 with regard to the manner of its mounting. It is only the differences to the first embodiment example which are described hereinafter. Otherwise the preceding description is referred to. Concerning this second embodiment example, the valve element 30 is rotatably mounted on a bearing pin or bearing bolt 66. The bearing bolt 66 extends in the axial direction of the longitudinal axis X from the base into the inside of the pump casing 6. The valve element 30 on its wall 34 comprises an integrally formed suction stub 68 which instead of the inlet stub 46 is engaged with the suction port 28 of the impeller 18. A suction opening, in which a bearing sleeve 70 is held via connection webs, is located in the inside of the suction stub 68, wherein the bearing sleeve 70 is configured as one piece with the remaining part of the valve element 30. The bearing sleeve 70 is placed on the bearing bolt 66 which is to say rotates on the bearing bolt 66. Furthermore, a spring 72 in the form of a compression spring is arranged in a manner surrounding the bearing bolt 66. The spring 72 assumes the function of the spring ring 42 according to the first embodiment example and generates a pressing force between the base of the pump casing 6 and the valve element 30, so that this in the released position which is shown in FIG. 14 can be pressed away from the inner wall of the pump casing 6 and can freely rotate. In this position, the bearing sleeve 70 with its closed axial end 74 which is away from the pump casing 6 is supported on the axial end of the rotor shaft 16. The manner of functioning of the valve element 30 corresponds to the preceding description. No differences result with the exception of the different mounting.

[0054] The third embodiment example according to FIGS. 15 to 17 corresponds essentially to the second embodiment example so that it is again only the differences which are described hereinafter. Otherwise the preceding description is referred to.

[0055] The valve element 30 in the inside comprise as spiral flow guide 46 which forms a spiral channel to the switching opening 48. The flow guide 46 is configured as a spiral projection which becomes narrower in the radial direction towards the switching opening 48, so that the free space between the flow guide 76 and the impeller 18 enlarges, so that a spirally widening flow channel to the outlet opening 48 is created. Herein, on operation, the flow runs in the rotation direction A in FIGS. 16 and 17. Since the flow guide 76 rotates together with the valve element 30 between the switching positions, an optimal flow guidance to each of the delivery connections 22 and 24 is always given on operation. It is to be understood that such a flow guide 76 could also be used with the first two embodiment examples.

[0056] Furthermore, the valve element 30 comprises a weight 78 which is arranged in a receiver in the base or the wall 34 of the valve element 30. The weight 78 lies diametrically opposite the switching opening 48 so that it lies at the bottom in the first switching position which is shown in FIG. 16. The weight 78 serves as a restoring element, so that the drive motor 2 merely needs to be driven in one rotation direction A. For restoring the valve element 30, it is not necessary to generate an annular flow in the opposite direction in the inside of the valve element 30. In contrast, the restoring is effected by way of gravity when the weight 78 moves downwards. If the pump assembly is to be brought into operation in the first switching position which is shown in FIG. 16, then the drive motor 2 is driven or accelerated by the control electronics 64 such that such a high pressure builds up in a direct manner that the spring force which is generated by the spring 72 can be overcome by a pressure force in the inside of the valve element 30. This means that the valve element 30 is pressed against the spring force of the spring 42 into bearing contact with the inner wall of the pump casing 6 by way of the generated fluid pressure so that it is frictionally fixed there and remains in the shown first switching position. In order to move the valve element 30 into the second switching position which is shown in FIG. 17, the drive motor 2 is brought into operation in an accordingly slower manner by the control electronics 64, so that an annular flow can firstly build up in the direction of the rotation direction A, said flow co-rotating the valve element 30 in the released position which is shown in FIG. 14. and therefore rotating it into the second switching position which is shown in FIG. 17. In this second switching position, the drive motor can be accelerated further, so that again such a fluid pressure builds up in the inside of the valve element 30 that the valve element 30 is pressed into the bearing position. On switching off the drive motor, the annular flow as well as the built-up pressure ceases, and the valve element 30 gets into its released position again due to the action of the spring 72. In this released position, the element can freely rotate again and the weight 78 produces a torque, so that the valve element 30 automatically rotates counter to the rotation direction A back into the first switching position which is shown in FIG. 16.

[0057] It is to be understood that such a restoring element can also be applied with the first two embodiment examples. Instead of a restoring element which acts by way of gravity, for example a spring or a magnetically acting restoring element could also be applied.

[0058] Instead of or additionally to an axial movement of the complete valve element 30, 30, 30 between the released and the bearing position, also only a movable section of the valve element 30, 30, 30 could be moved between a released and a bearing position. Thus for example the annular wall 32 can be configured in an elastic manner, in order to be deformed by a fluid pressure which prevails in the inside and to be brought to bear against an inner wall of the pump casing 6.

[0059] 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.