EP3376039B1 - Centrifugal pump assembly - Google Patents

Description

The invention relates to a centrifugal pump unit with an electric drive motor, an impeller driven by this and a rotatable valve element integrated into the centrifugal pump unit.

Centrifugal pump units are known which have a movable, in particular pivotable valve element in the pump housing in order to selectively direct the liquid flow conveyed by the centrifugal pump unit into two different pressure-side flow paths, in particular depending on the direction of rotation of the drive motor. Arrangements are also known in which a switching device between two suction-side flow paths is integrated into the centrifugal pump unit. Such an arrangement is, for example, off DE 90 139 92 U1 famous. This known switching device has an inflow element located on the pressure side of the impeller which, depending on the direction of rotation, switches the valve device on the suction side. This requires a relatively complex mechanism.
A similar device is out U.S. 5,924,432 known, which shows a direction of rotation movable valve element inside a pump housing. This valve element is rotatably mounted on a screw inside the pump housing.

In view of this prior art, it is the object of the invention to provide a centrifugal pump unit with an integrated valve element to the effect that a simpler structure of the centrifugal pump unit is achieved with simultaneously increased reliability of the switching function of the valve element.

This object is achieved by a centrifugal pump unit with the features specified in claim 1. Preferred embodiments emerge from the subclaims, the following description and the attached figures.

The centrifugal pump assembly according to the invention has an electric drive motor, by means of which at least one impeller can be driven in rotation. For this purpose, the impeller is rotatably connected to the magnet rotor of the drive motor, either directly or z. B. over a wave. The drive motor is preferably designed as a wet-running electric drive motor, d. H. it preferably has a can or a can between the stator and rotor, so that the rotor rotates in the liquid to be conveyed by the impeller. The impeller is arranged in a pump housing which defines the flow paths to and from the impeller. In the pump housing, a valve element is also arranged, which is rotatable between at least two switching positions. This can, for example, be a valve element of a switchover valve or mixing valve, as will be described below.

According to the invention, the valve element is rotatably held on a bearing in the interior of the pump housing. The storage of the valve element in the interior of the pump housing avoids shaft seals in the pump housing, which would be necessary if the bearing were arranged outside the pump housing. According to the invention, the bearing is arranged in a storage space which is separated by at least one seal from the rest of the interior space of the pump housing, which receives a fluid to be pumped or a liquid to be pumped. The pump unit is preferably designed for water as the fluid to be conveyed. So the centrifugal pump unit is suitable for. B. for use as a circulation pump in a heating and / or air conditioning system. The seal of the storage room compared to the interior of the pump housing has the advantage that impurities in the fluid to be conveyed are essentially kept away from the storage. At the same time, however, no absolutely hermetic seal is required, which would be required if the bearing were arranged outside the pump housing. According to the invention, a certain amount of leakage is tolerated in the bearing. Nevertheless, liquid cannot escape to the outside of the pump housing. Because impurities are kept away from the bearing, a smooth mounting of the valve element can be ensured. The smooth mounting is advantageous if the valve element is to be moved by the drive motor without an additional drive, in particular by hydraulic coupling via the fluid to be conveyed.

The storage space can preferably be formed in one piece with the valve element. I. E. at least one section of a wall which delimits the storage space is formed in one piece with at least one wall of the valve element. The storage space is particularly preferably formed by an indentation on a wall of the valve element, in particular an end face of the valve element. The storage space preferably has a tubular or blind hole shape.

According to a preferred embodiment of the invention, the at least one bearing in the interior of the storage space can be lubricated by a lubricant, preferably at the factory. The lubricant can be, for example, a grease or another suitable lubricant. The lubricant is preferably introduced at the factory, ie the lubricant is already arranged in the storage room when the centrifugal pump unit is delivered. Since the seal of the storage room is not absolutely tight, but allows a certain amount of the liquid to be pumped through, it is possible to that in the course of time the lubricant is diluted and replaced by the liquid to be pumped or the fluid to be pumped during operation of the centrifugal pump unit. Then, in the course of time, the liquid to be pumped can take over the function of the lubricant. That is to say, the bearing is preferably designed in such a way that the fluid to be conveyed or the liquid to be conveyed can serve as a lubricant.

The bearing is particularly preferably designed as a slide bearing. This enables a very simple storage structure. Furthermore, such a bearing can also be lubricated by the liquid to be conveyed.

According to the invention, the seal is not completely tight for that fluid or the liquid which the centrifugal pump assembly is designed to convey. The fluid to be conveyed is preferably water, so that the seal is adjusted accordingly so that it allows a certain amount of liquid or water to pass through. This has the advantage that the seal can be made simpler and, moreover, the friction in the area of the seal can be reduced. In addition, permanent lubrication of the bearing can advantageously be ensured if the penetrating liquid, in particular the penetrating water, takes on the function of a lubricant over time. However, the seal is advantageously designed in such a way that it retains particles located in the fluid to be conveyed by the impeller. In this way, impurities are kept away from the bearing, so that the ease of movement of the at least one bearing in the storage room is ensured in the long term.

The storage space can be designed in such a way that it is only open on one side to the interior of the pump housing, so that a seal is arranged on only one side of the bearing. It is however, it is also conceivable that the storage space is designed in such a way that a seal is arranged on each of two sides of the bearing, which seal seals the storage space in the manner described from the rest of the interior of the pump housing.

The at least one bearing is particularly preferably arranged centrally on the valve element. That is, the bearing centrally surrounds the axis of rotation of the valve element. This has the advantage that the bearing can be made very small in diameter, so that the friction in the bearing is reduced. In addition, the valve element preferably projects in the radial direction over the bearing, so that in this area there are favorable lever ratios for rotating the valve element about the at least one bearing. The diameter of the bearing is preferably less than a quarter of the diameter of the valve element.

More preferably, the at least one bearing is located in an area of the pump housing located on the suction side of the impeller. This means that at least one bearing is located in the area of the pump housing through which the liquid sucked in by the impeller flows. This has the advantage that the mounting of the valve element does not collide with the impeller and the drive motor.

According to a particularly preferred embodiment, the at least one valve element is mechanically, magnetically and / or hydraulically coupled to the drive motor for its movement between the switching positions. For this purpose, a coupling can be provided between the drive motor and the valve element, for example between a rotor shaft or the impeller on one side and the valve element on the other. The clutch can be designed to be non-positive and / or frictional. More preferably, the coupling can be releasable so that it can be brought out of engagement in a targeted manner. This can be done, for example, depending on the speed of the Drive motor and / or the pressure in the pressure side area of the pump housing happen. Thus, the valve element can also be moved between the switching positions in a targeted manner by the drive motor, without a separate drive for the valve element being required. If the drive motor is hydraulically coupled to the valve element, this hydraulic coupling preferably takes place via the fluid set in motion by the impeller. In particular, the fluid or the liquid in the pump housing can be set in a rotary movement by the impeller, which is transmitted to the valve element by friction, so that the valve element is rotated by the flow and can thus be moved between the switching positions. In order to enable reciprocal movement between two switching positions, the drive motor and thus the impeller can preferably be driven in two opposite directions of rotation, so that the rotating flow in the pump housing also optionally runs in different directions of rotation. The hydraulic coupling has the advantage that it can easily disengage due to slippage. That is, when the valve element reaches a predetermined switching position and is fixed in this position, the flow can continue in the pump housing without moving the valve element any further. The flow then causes friction on the surface of the valve element, which, however, essentially corresponds to the usual hydraulic friction on the inside of the pump housing. In particular for the hydraulic as well as for the mechanical clutch, it is also advantageous if the axis of rotation of the valve element is aligned with the axis of rotation of the drive motor.

According to a further preferred embodiment, at least one force generating means can be present which exerts a force on the at least one valve element in the direction of one of the at least two switching positions, the force preferably being a spring force, a magnetic force and / or the force of gravity. With such a In an embodiment, the valve element can be automatically moved back into a starting position, which preferably corresponds to one of the switching positions, by the force generating means when the drive motor is switched off. That is, in this embodiment, no reversal of the direction of rotation of the drive motor is required in order to move the valve element back into its starting position. The valve element can be moved from the starting position into the other switching position due to a coupling with the drive motor by its rotation. In particular, in order to keep the valve element in the starting position when the drive motor is in operation, a second clutch can be provided which fixes the valve element in this position, in particular with a friction fit. This coupling can, for example, be pressed into a coupled and thus holding position by the pressure in the interior of the pump housing, which is caused by the impeller. With such a configuration, whether or not the valve element is moved from the initial position can be achieved by appropriate control of the drive motor. The drive motor is preferably provided with a control device which makes it possible to regulate the speed and / or acceleration of the drive motor. If, for example, the drive motor is accelerated very quickly, this can lead to a pressure building up very quickly in the pump chamber, which can be used to quickly engage a coupling that fixes the valve element before the valve element is in the other switch position is moved. In this way, the valve element can be held in its starting position. If, on the other hand, the drive motor is accelerated slowly, a rotating flow can develop in the pump housing before the pressure is so high that the valve element is fixed. The valve element can then be moved into the other switching position by the flow.

The at least one bearing preferably allows an axial movement of the valve element between a first and a second position. This configuration makes it possible to move the valve element axially to make it z. B. in the second position in a sealing and holding system with the pump housing or a contact surface connected to the pump housing. In this position, the valve element can then, for example, bear against at least one valve seat in a sealing manner. At the same time, the system can take over the function of the above-described second coupling for fixing the valve element. In the first position, however, the valve element is preferably spaced from the contact surfaces so that it can preferably rotate freely about the at least one bearing.

The first position and / or the second position are preferably limited by a stop, with at least one of the stops preferably being located within the storage space. In the second position, the stop can be formed, for example, by a contact surface in which the valve element comes to rest. A second stop is preferably provided in the opposite direction so that the valve element cannot move further than a predetermined amount away from the contact surface or the pump housing.

At least one restoring element, in particular a restoring spring, is also preferably provided, which exerts a restoring force on the valve element in the axial direction. The restoring element is preferably arranged in such a way that it moves the valve element into a position in which it is spaced from an abutment and / or sealing surface and is freely rotatable about the at least one bearing. The valve element is preferably pressed against the restoring element by a pressure force generated in the pump housing. For this purpose, the valve element preferably has a pressure surface, which is a pressure chamber facing inside the pump housing and on which the liquid pressure generated by the impeller inside the pump housing acts. If the force generated by the restoring element is exceeded by this pressure force, the valve element moves against the restoring element into a holding and / or sealing position, as has been described above.

The restoring element is preferably arranged within the storage space. It is protected from contamination by the at least one seal. According to a further particularly preferred embodiment of the invention, the valve element is arranged in the pump housing in such a way that it separates a suction chamber connected to a suction side of the impeller from a pressure chamber connected to the pressure side of the impeller. With this arrangement, the differential pressure between suction chamber and pressure chamber can be used to press the valve element against a sealing or contact surface, on the one hand to seal the suction side against the pressure side and on the other hand to seal valve openings in the desired manner. At the same time, a coupling can be created which fixes the valve element in a desired switching position when it rests on the contact surface. For this purpose, facing the pressure chamber, the valve element preferably has a pressure surface in the manner described, on which the pressure on the output side of the impeller acts.

The centrifugal pump assembly further preferably has two alternative flow paths, the at least one valve element being arranged in these flow paths in such a way that the flow paths are opened differently in the at least two switching positions. The valve element can be designed as a pure switchover valve in such a way that in a first switching position it opens a first flow path and closes a second flow path and vice versa in one second switching position closes the first flow path and opens the second flow path. A valve element in the context of this invention is also to be understood as a coupled arrangement of two valve elements which are moved coupled with one another. Alternatively or additionally, the valve element can provide a mixing function in that it can, for example, also assume intermediate positions between the two switching positions described, in which both flow paths are open to a certain extent. By shifting the valve element in these intermediate positions, the flow paths can be opened to different degrees, so that a mixing ratio of the flows through the two flow paths can be changed. The valve element is preferably designed and arranged in such a way that, when it moves, it opens one of the flow paths by the same amount by which the other flow path is closed at the same time.

The two flow paths are particularly preferably located on the suction side of the impeller. That is, depending on the position of the valve element, the impeller sucks in from one of the two flow paths or from both flow paths, whereby the mixture of the flows from the two flow paths can then be changed by shifting the valve element. Alternatively, the valve element can also be located on the pressure side of the impeller or cause it to switch the flow between two pressure-side flow paths or, if configured as a mixing valve, mix it.

Fig. 1

eine Explosionsansicht des Kreiselpumpenaggregates gemäß einer neunten Ausführungsform der Erfindung,

Fig. 2

eine perspektivische Ansicht des Kreiselpumpenaggregates gemäß Fig. 1 mit abgenommenem Pumpengehäuse und Ventilelement,

Fig. 3

eine perspektivische Ansicht der Motorwelle des Kreiselpumpenaggregates gemäß Fig. 1 und 2 sowie des Kupplungsteils des Ventilelementes,

Fig. 4

eine Schnittansicht des Kreiselpumpenaggregates gemäß Fig. 1 mit dem Ventilelement in einer ersten Position,

Fig. 5

eine Schnittansicht gemäß Fig. 4 mit dem Ventilelement in einer zweiten Position,

Fig. 6

eine Draufsicht auf das geöffnete Pumpengehäuse des Kreiselpumpenaggregates gemäß Fig. 1 bis 3 mit dem Ventilelement in einer ersten Schaltstellung,

Fig. 7

eine Ansicht gemäß Fig. 6 mit dem Ventilelement in einer zweiten Schaltstellung,

Fig. 8

eine Ansicht gemäß Fig. 6 und 7 mit dem Ventilelement in einer dritten Schaltstellung,

Fig. 9

schematisch den hydraulischen Aufbau einer Heizungsanlage mit einem Kreiselpumpenaggregat gemäß Fig. 1 bis 8,

Fig. 10

eine Explosionsansicht eines Kreiselpumpenaggregates gemäß einer zweiten Ausführungsform der Erfindung,

Fig. 11

eine perspektivische Ansicht des geöffneten Ventilelementes des Kreiselpumpenaggregates gemäß Fig. 10,

Fig. 12

eine perspektivische Ansicht des geschlossenen Ventilelementes gemäß Fig. 11,

Fig. 13

eine Schnittansicht des Kreiselpumpenaggregates gemäß Fig. 10 mit dem Ventilelement in einer ersten Position,

Fig. 14

eine Schnittansicht gemäß Fig. 13 mit dem Ventilelement in einer zweiten Position,

Fig. 15

eine Draufsicht auf das geöffnete Pumpengehäuse des Kreiselpumpenaggregates gemäß Fig. 10 bis 14 mit dem Ventilelement in einer ersten Schaltstellung,

Fig. 16

eine Ansicht gemäß Fig. 15 mit dem Ventilelement in einer zweiten Schaltstellung,

Fig. 17

eine Ansicht gemäß Fig. 15 und 16 mit dem Ventilelement in einer dritten Schaltstellung,

Fig. 18

eine Ansicht gemäß Fig. 15 bis 17 mit dem Ventilelement in einer vierten Schaltstellung und

Fig. 19

schematisch den hydraulischen Aufbau einer Heizungsanlage mit einem Kreiselpumpenaggregat gemäß Fig. 10 bis 18,

Fig.20

vergrößert eine Darstellung der Lagerung des Ventilelementes 18, 18i in den Ausführungsbeispielen gemäß Fig. 1 bis 19.

The invention is described below by way of example with reference to the accompanying figures. In this shows:

Fig. 1

an exploded view of the centrifugal pump unit according to a ninth embodiment of the invention,

Fig. 2

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

Fig. 3

a perspective view of the motor shaft of the centrifugal pump assembly according to Fig. 1 and 2 as well as the coupling part of the valve element,

Fig. 4

a sectional view of the centrifugal pump assembly according to Fig. 1 with the valve element in a first position,

Fig. 5

a sectional view according to Fig. 4 with the valve element in a second position,

Fig. 6

a plan view of the open pump housing of the centrifugal pump assembly according to FIG Figs. 1 to 3 with the valve element in a first switching position,

Fig. 7

a view according to Fig. 6 with the valve element in a second switching position,

Fig. 8

a view according to Figures 6 and 7 with the valve element in a third switching position,

Fig. 9

schematically the hydraulic structure of a heating system with a centrifugal pump unit according to Figures 1 to 8 ,

Fig. 10

an exploded view of a centrifugal pump unit according to a second embodiment of the invention,

Fig. 11

a perspective view of the opened valve element of the centrifugal pump assembly according to FIG Fig. 10 ,

Fig. 12

a perspective view of the closed valve element according to FIG Fig. 11 ,

Fig. 13

a sectional view of the centrifugal pump assembly according to Fig. 10 with the valve element in a first position,

Fig. 14

a sectional view according to Fig. 13 with the valve element in a second position,

Fig. 15

a plan view of the open pump housing of the centrifugal pump assembly according to FIG Figures 10-14 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,

Fig. 17

a view according to Figures 15 and 16 with the valve element in a third switching position,

Fig. 18

a view according to Figures 15-17 with the valve element in a fourth switching position and

Fig. 19

schematically the hydraulic structure of a heating system with a centrifugal pump unit according to Figures 10 to 18 ,

Fig. 20

shows an enlarged illustration of the mounting of the valve element 18, 18i in the exemplary embodiments according to FIG Figures 1 to 19 .

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 transfer medium, in particular water, is circulated by the centrifugal pump assembly.

The centrifugal pump unit according to both embodiments of the invention has a motor housing 2 in which an electric drive motor is arranged. This has, in a 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 can or a can 10. This means that 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 an impeller 14 that is non-rotatably connected to the rotor shaft 8 rotates.

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

A movable valve element 18 is also 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, namely so 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 fixed in a rotationally fixed manner on the bottom of the pump housing 12. The valve element 18 is not only rotatable about the axis 20, but can also be moved to a certain extent in the longitudinal direction X. This linear mobility is limited in one direction by the pump housing 12, against which the valve element 18 strikes with its outer circumference.

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

In both of the embodiments shown, a mechanical coupling is provided between the drive motor and the valve element, and in these embodiments the drive motor can be controlled by the control device 17 in two different operating modes or operating modes. In a first operating mode, which corresponds to normal operation of the circulating pump assembly, the drive motor rotates in a conventional manner at a desired speed, in particular adjustable by the control device 17. In the second operating mode, the drive motor is controlled in open-loop mode, so that the rotor can be rotated step by step in individual angular steps specified by the control device 17, which are smaller than 360 °. The drive motor can thus be moved in individual steps in the manner of a stepping motor, which is used in these exemplary embodiments to move the valve element into a defined position in a targeted manner in small angular steps, as will be described below.

In the first embodiment according to Fig. 19 a mixing valve is integrated in the pump housing 2, as can be used, for example, to set the temperature for underfloor heating.

The motor housing 2 with the electronics housing 16 corresponds to the configuration described above. In addition to the pressure connection 27, the pump housing 12 has two suction-side connections 32 and 34 which open into inlets 28 and 30 at the bottom of the pump housing 12, which are located in a plane transverse to the axis of rotation X.

The valve element 18 is drum-shaped and consists of a cup-shaped lower part 76 which is closed by a cover 78 on its side facing the impeller 14. A suction opening 36 is formed in the central region of the cover 78. The suction opening 36 is in engagement with the suction mouth 38 of the impeller 14. The valve element 18 is rotatably mounted on a shaft 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 moved by a spring 48 into the position shown in FIG Fig. 5 The rest position shown is pressed, in which the valve element 18 is in a released position in which the lower part 76 does not lie against the bottom of the pump housing 12, so that the valve element 18 is essentially freely rotatable about the axis 20. The front end of the rotor shaft 8, which is designed as a coupling 108, functions as an axial stop in the released position. The coupling 108 engages with a mating coupling 110 which is arranged non-rotatably on the valve element 18. The coupling 108 has beveled 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 mating coupling 110 is only possible in one direction of rotation is, namely in the direction of rotation A in Fig. 3 . In the opposite direction of rotation B, on the other hand, the clutch slips, causing the valve element 18 to move axially. The direction of rotation B is that direction of rotation in which the pump unit is driven in normal operation. The direction of rotation A, on the other hand, is used for the targeted adjustment of the valve element 18. This means that a coupling that is dependent on the direction of rotation is formed here. In addition, however, the mating clutch 110 disengages from the clutch 108 due to the pressure in the pressure chamber 26. If the pressure in the pressure chamber 26 increases, a pressure force acts 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 adjacent position, which in Fig. 4 is shown. In this, the lower part 76 rests against the bottom side of the pump housing 12, so that on the one hand the valve element 18 is held in a force-locking manner and on the other hand a tight contact is achieved which seals the pressure and suction sides from one another in the manner described below.

The suction connection 32 opens out at the inlet 28 and the suction connection 34 opens out at the inlet 30 in the bottom of the pump housing 12 in the interior thereof, that is to say in the suction space 24. The lower part 76 of the valve element 18 has in its bottom an arcuate opening 112 which extends essentially over 90 °. Fig. 6 shows a first switching position in which the opening 112 only covers the inlet 30, so that a flow path is only given from the suction connection 34 to the suction opening 36 and thus to the suction mouth 38 of the impeller 14. The second inlet 28 is tightly closed by the base of the valve element 18 resting in its circumferential area. Fig. 8 shows the second switching position in which the opening 112 only covers the inlet 28, while the inlet 30 is closed. In this switching position there is only one flow path from the suction connection 32 to the suction mouth 38 open. Fig. 7 now shows an intermediate position in which the opening 112 covers both inlets 28 and 30, the inlet 30 being only partially released. By changing the degree of release of the connection 30, a mixing ratio between the flows from the inlets 28 and 30 can be changed. Via the step-by-step adjustment of the rotor shaft 8, the valve element 18 can also be adjusted in small steps in order to change the mixing ratio.

Such a functionality can for example in a hydraulic system, as it is in Fig. 9 is shown to apply. There the centrifugal pump unit with the integrated valve, as described above, is indicated by the dashed line 1. The hydraulic circuit has a heat source 114 in the form of, for example, a gas boiler, the outlet of which opens into, for example, the suction connection 34 of the pump housing 12. In this example, an underfloor heating circuit 116 connects to the pressure connection 27 of the centrifugal pump unit 1, the return of which is connected both to the inlet of the heat source 114 and to the suction connection 32 of the centrifugal pump unit. A further heating circuit 120 can be supplied with a heat transfer medium, which has the temperature of the heat source 114 on the outlet side, via a second circulating pump assembly 118. The flow temperature of the underfloor heating circuit 116, on the other hand, can be regulated in such a way that cold water from the return is mixed with the hot water on the outlet side of the heat source 114, with the mixing ratio being changed by changing the opening ratios of the inlets 28 and 30 in the manner described above Rotation of the valve element 18h can be changed.

The second embodiment according to Figures 10 to 19 shows a centrifugal pump unit which, in addition to the mixer functionality described above, also has a switchover functionality for has additional supply of a secondary heat exchanger for domestic water heating.

The mounting and the drive of the valve element 18i takes place in this embodiment in the same way as in the ninth embodiment. In contrast to the valve element 18, the valve element 18i has, in addition to the opening 112, a through-channel 122 which extends from an opening 124 in the cover 78i to an opening in the bottom of the lower part 76i and thus connects the two axial ends of the valve element 18i with one another. Furthermore, an arcuate bridging opening 126 is formed in the valve element 18i only to the underside, that is to say to the bottom of the lower part 76i and thus to the suction chamber 24, which is closed to the pressure chamber 26 by the cover 78i.

In addition to the pressure connection 27 and the two suction connections 34 and 32 described above, the pump housing 12 has a further connection 128. The connection 128 opens into an inlet 130 in the bottom of the circulation pump assembly 12 in addition to the inlets 28 and 30 into the suction chamber 24. Based on Figures 15 to 18 the various switching positions are explained, the cover 78i of the valve element 18i being shown partially open in these figures in order to clarify the position of the openings below. Fig. 15 shows a first switching position in which the opening 112 is opposite the inlet 30, so that a flow connection is established from the suction connection 34 to the suction mouth 38 of the impeller 14. In the switch position according to Fig. 16 the opening 112 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 another switch position, which Fig. 17 shows, the opening 112 lies above the inlet 30, so that in turn a flow connection from the suction connection 34 is given to the suction mouth 38 of the impeller 14. At the same time, there is a partial overlap of the opening 124 and the through hole 122 with the inlet 28, so that a connection is established between the pressure chamber 26 and the suction connection 32, which here functions as a pressure connection. At the same time, the bridging opening 126 simultaneously covers the input 130 and part of the input 28, so that a connection is also created from the connection 128 via the input 130, the bridging opening 126 and the input 28 to the connection 32.

Fig. 18 shows a fourth switching position in which the through-channel 122 completely covers the inlet 28, so that the connection 32 is connected to the pressure chamber 26 via the through-channel 122 and the opening 124. At the same time, the bridging opening 126 only covers the input 130. The opening 112 continues to cover the input 30.

Such a centrifugal pump unit can, for example, be used in a heating system as shown in Fig. 19 is shown to find use. There, the dashed line delimits the centrifugal pump unit 1, as it is based on the Figures 10 to 18 has been described. The heating system in turn has a primary heat exchanger or a heat source 114, which can be a gas boiler, for example. On the output side, the flow path runs into a first heating circuit 120, which can be formed, for example, by conventional heating elements or radiators. At the same time, a flow path branches off to a secondary heat exchanger 56 for heating domestic water. The heating system also has an underfloor heating circuit 116. The returns of the heating circuit 120 and the underfloor heating circuit 116 open into the suction connection 34 on the pump housing 12. The return from the secondary heat exchanger 56 opens into the connection 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 underfloor heating circuit 116.

When the valve element 18i is in the first in Fig. 15 is located, the impeller 14 conveys liquid from the suction connection 34 via the pressure connection 27 through the heat source 140 and the heating circuit 120 and back to the suction connection 34. If the valve element 18i is in the second switching position, which is shown in FIG Fig. 16 is shown, the system is switched to domestic water operation, in this state the pump unit or the impeller 14 pumps liquid from the connection 128, which serves as a suction connection, through the pressure connection 27, via the heat source 114 through the secondary heat exchanger 56 and back to the connection 128. If the valve element 18i is in the third switching position, which is shown in Fig. 17 is shown, the underfloor heating circuit 116 is also supplied. The water flows through the suction connection 34 into the suction mouth 38 of the impeller 14 and is conveyed through the first heating circuit 120 via the pressure connection 27 via the heat source 114 in the manner described. At the same time, on the outlet side of the impeller 14, the liquid exits the pressure chamber 26 into the opening 124 and through the passage 122 and thus flows to the connection 32 and via this into the underfloor heating circuit 116.

In the in Fig. 17 The switching position shown flows simultaneously via the bridging opening 126 via the connection 128 and the inlet 130 into the connection 32. That is, here water flows via the heat source 114 through the secondary heat exchanger 26 and the connection 128 to the connection 32 Secondary heat exchanger 56, if essentially no heat is removed, hot water is added to the connection 32 in addition to the cold water which flows from the pressure chamber 26 via the through-channel 122 to the connection 32. By changing the The amount of warm water added at connection 32 can be varied via the valve position 18i. Fig. 18 shows a switching position in which the admixture is switched off and the connection 32 is only in direct connection with the pressure chamber 26. In this state, the water in the floor circuit 116 is conveyed in the circuit without the supply of heat. It can be seen that by changing the switching positions of the valve element 18i in this embodiment, both a switchover between heating and domestic water heating 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 114 and an underfloor heating circuit 116 with a temperature reduced via a mixing function.

Due to the fact that the clutch 108 and the mating clutch 110 disengage in the first operating mode during normal operation of the circulating pump unit when the impeller 14 is delivering liquid, the problem arises when changing to the second operating mode, which requires a reversal of the direction of rotation To bring the rotor 6 and the valve element 18, 18i back into a defined alignment with respect to their angular positions. The valve element 18, 18i should essentially be held in the position in which it was when the pump assembly was changed from the second operating mode to the first operating mode by the control device 17 for the last time. At the same time, the control device 17 knows the position of the rotor 6 and the control device 17 is designed such that it stores the rotor position. However, since it cannot be completely ruled out that the valve element 18, 18i may have shifted by a small amount, when changing to the second operating mode again, the rotor 6 is preferably first positioned in such a way that the control device 17 moves the rotor 6 by controlling the stator 4 accordingly, it does not rotate all the way into the stored angular position, but rather preferably stops shortly before. I. E. In a first step, when the second operating mode is put into operation, the rotor 6 is rotated into a previously stored angular position or in an angular position which is slightly before the last angular position stored in the direction of rotation. The rotor can then be rotated together with the valve element 18, 18i into a desired second angular position, the control device 17 controlling the stator 6 in such a way that the rotor 6 rotates precisely by the desired angle in this second operating mode. During this rotation, the mating coupling 110 is taken along via the coupling 108, so that the valve element 18, 18i is then rotated into the desired angular position. In this, the rotor 6 is stopped and the control device 17 switches back to the first operating mode or the first operating mode and starts the rotor 6 in the opposite direction of rotation, so that the clutch 108 can disengage from the mating clutch 110 and otherwise through the axial Displacement of the valve element 18, 18i due to the pressure generated in the pressure chamber 26, the clutch 108 and the mating clutch 110 completely disengage and the valve element 18, 18i is held in the switch position reached by resting on the bottom of the pump housing 12.

The coupling 108 has two bevels or wedge surfaces 132 which extend starting from two end edges 134 which run essentially in a diametrical direction with respect to the axis of rotation X. On the side of the end edges 134 facing away from the wedge surfaces 132, engagement surfaces 136 extend, which essentially run in a plane which is spanned by the axis of rotation X and a diameter line to this axis of rotation X. The mating coupling 110 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 parallel side surfaces, which in turn extend in planes which in the Essentially spanned by the diameter line and the axis of rotation X or axes parallel to these. The side surfaces of the projection 138 abut 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 with axial displacement. In this embodiment of the coupling 108 and the mating coupling 110 there are exactly two positions offset by 180 ° in relation to one another, in which the rotor 6 and the valve element 18, 18i can be coupled to one another.

Based on Fig. 20 the mounting of the valve element 18, 18i in the exemplary embodiments described above is described in detail again. The storage is designed identically in both embodiments. Starting from the bottom of the pump housing 12, a stationary axis extends in the direction of the axis of rotation X into the interior of the pump housing 12. The valve element 18, 18i is rotatably mounted on this axis. The axle 20 engages in a blind hole 140 in the bottom of the valve element 18, 18i, which is remote from the impeller 14. In the area of the opening of the blind hole 140, a seal 142 is arranged, which is in sliding contact with the outer circumference of the axle 20. The seal 142 seals the interior of the blind hole 140 from the outside. This prevents liquid from penetrating from the interior of the pump housing 12 into this storage space formed by the blind hole 140. A lubricant can be arranged in the blind hole 140 in order to permanently lubricate or prelubricate the sliding bearing. According to the invention, however, it is provided that the seal 142 allows a small amount of leakage, so that, in the long term, liquid from the pump housing 12, in particular water, can penetrate the interior of the blind hole 140 and is used there for lubrication between the valve element 18, 18i and the axis 20. In this case, however, the seal 142 is designed in such a way that particles and contaminants are retained so that permanent ease of movement is ensured.

In the in Fig. 20 The embodiment shown, the radial bearing of the valve element 18, 18i takes place on the outer circumference of the spring 48. It should be understood, however, that the radial bearing could alternatively also take place directly on the outer circumference of the axle 20, for example in the section of the storage space or blind hole adjoining the seal 142 140

The axle 20 also has a circumferential shoulder 144 facing the impeller 14, at which the axle 20 tapers. The spring 48, the function of which has already been described above, is supported between this shoulder 144 and the bottom of the blind hole 140, which is located at the end facing the impeller 14. In this way, the spring 48 is also located completely inside the blind hole 140, which defines the storage space, so that the spring 48 is also protected from contamination from the fluid conveyed by the pump assembly.

It is to be understood that the bearing described could also be used together with the valve element 18, 18i if this were hydraulically coupled instead of via the mechanical coupling 108, 110 described. If the aforementioned coupling 108, 110 is omitted, the valve element could instead be rotated by the flow set in rotation by the impeller 14 in the pressure chamber 26, in that the flow acts on the cover 78, 78i. In addition, in such an embodiment, stops could be present which define the switching positions of the valve element 18, 18i. The movement between these switching positions could then be achieved by reversing the direction of rotation of the impeller 14.

It is to be understood that individual features from the exemplary embodiments described above could also be combined with one another in other ways. In addition, in the exemplary embodiments, the pump housing 12, which at the same time serves as a valve housing, is designed in one piece. It is to be understood, however, that the pump housing 12 could also be composed of several individual parts or could be designed in several parts.

List of reference symbols

1

Centrifugal pump unit

2

Motor housing

4th

stator

6th

rotor

8th

Rotor shaft

10

Can

12th

Pump housing

14th

Wheel

16

Electronics housing

17th

Control device

18 18i

Valve element

20th

axis

24

Suction chamber

26th

Printing room

27

Pressure connection

28, 30

Entrances

32.34

Suction connections

38

Suction mouth

48

feather

76 76i

Lower part

78, 78i

lid

108

coupling

110

Mating coupling

112

opening

114

Heat source

116

Underfloor heating circuit

118

Circulation pump unit

120

Heating circuit

122

Passage channel

124

opening

126

Bypass opening

128

connection

130

entrance

132

Wedge surfaces

134

Front edges

136

Engagement surfaces

138

head Start

140

Blind hole or storage room

142

poetry

144

shoulder

X

Axis of rotation

AWAY

Directions of rotation

Claims (17)

1. A centrifugal pump assembly with an electrical drive motor, with at least one impeller (14) which is driven by this motor as well as with a pump casing (12) which surrounds the impeller (14) and in which at least one valve element (18, 18i) which is rotatable between two switching positions is arranged,
   whereby
   the valve element is rotatably held on at least one bearing in the interior of the pump casing (12), wherein the bearing is arranged in a mounting space (140) which is separated from the remaining interior of the pump casing (12) which receives a fluid to be delivered, by at least one seal (142)
   characterised in that
   the at least one seal (142) is not completely tight for that fluid, for whose delivery the centrifugal pump assembly is designed.
2. A centrifugal pump assembly according to claim 1, characterised in that the mounting space (140) at least in a section is delimited by a wall which is formed as one piece with the valve element (18, 18i).
3. A centrifugal pump assembly according to claim 1, characterised in that the at least one bearing in the inside of the mounting space (140) is lubricated by a lubricant, preferably on the part of the factory.
4. A centrifugal pump assembly according to one of the preceding claims, characterised in that the at least one seal (142) is designed in a manner such that it holds back the particles which are located in the fluid which is to be delivered by the impeller (14).
5. A centrifugal pump assembly according to one of the preceding claims, characterised in that a seal is arranged in each case at two sides of the bearing, between which seals the mounting space (140) is situated.
6. A centrifugal pump assembly according to one of the preceding claims, characterised in that it is designed for water as a fluid to be delivered.
7. A centrifugal pump assembly according to one of the preceding claims, characterised in that the at least one bearing is arranged centrally on the valve element (18, 18i).
8. A centrifugal pump assembly according to one of the preceding claims, characterised in that the at least one bearing is situated in a region of the pump casing (12) which is situated at the suction side of the impeller (14).
9. A centrifugal pump assembly according to one of the preceding claims, characterised in that the at least one valve element (18, 18i) is mechanically and/or hydraulically coupled to the drive motor for its movement between the switching positions.
10. A centrifugal pump assembly according to one of the preceding claims, characterised by a force generating means which exerts a force upon the at least one valve element (18, 8i) in the direction of one of the switching positions, wherein the force is preferably a spring force, a magnetic force and/or the gravity force.
11. A centrifugal pump assembly according to one of the preceding claims, characterised in that the at least one bearing permits an axial movement (X) of the valve element (18, 18i) between a first position and a second position.
12. A centrifugal pump assembly according to claim 11, characterised in that the first position and/or the second position are delimited by a stop, wherein preferably at least one of the stops is situated within the mounting space (140).
13. A centrifugal pump assembly according to claim 11 or 12, characterised by at least one restoring element (48), in particular a restoring spring (48), which exerts a restoring force upon the valve element (18, 18i) in the axial direction.
14. A centrifugal pump assembly according to claim 13, characterised in that the restoring element (48) is arranged within the mounting space (140).
15. A centrifugal pump assembly according to one of the preceding claims, characterised in that the valve element (18, 18i) is arranged in the pump casing (12) in a manner such that it separates a suction chamber (24) which is connected to a suction side of the impeller (14), from a delivery chamber (26) which connects to the delivery side of the impeller (14).
16. A centrifugal pump assembly according to one of the preceding claims, characterised in that it comprises two alternative flow paths, wherein the at least one valve element (18, 18i) is arranged in these flow paths in a manner such that the flow paths are opened to a different extent in the at least two switching positions.
17. A centrifugal pump assembly according to claim 16, characterised in that the two flow paths are situated at the suction side of the impeller (14).

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