Patent Application
20200056614
The invention relates to a centrifugal pump assembly with an electric drive motor and with a valve element which is arranged in the pump assembly and which is movable between at least two switching positions.
Centrifugal pump assemblies which simultaneously contain a valve device which permits the switching between two flow paths, through which the centrifugal pump assembly delivers, are known. Here, such valve devices which switch in a manner depending on the rotation direction of the centrifugal pump assembly are known. Such a centrifugal pump assembly which comprises a switch-over device, with the help of which one can switch between two inlets of the centrifugal pump assembly is known for example from DE 9013992 U1. The centrifugal pump assembly which is disclosed there comprises a relatively complicated mechanism which comprises an onflow element which is situated at the delivery side and which is subjected to onflow by the outlet-side flow produced by the centrifugal pump assembly and which can be moved into two different positions depending on the flow direction. A valve element at the suction side of the pump assembly is switched between the two inlets via a lever system which is connected to the onflow element.
With regard to this state of the art, it is the object of the invention to improve a centrifugal pump assembly with an integrated valve element, to the extent that a simpler construction of the centrifugal pump assembly is achieved with a simultaneously increased reliability of the switching function of the valve element.
The centrifugal pump assembly according to the invention comprises an electrical drive motor as well as at least one impeller which is rotatingly driven by this electrical drive motor. For this, a rotor of the electrical drive motor is connected to the impeller, for example via a shaft. The impeller is arranged in a pump casing which surrounds the impeller and which preferably outwards delimits the space filled with fluid to be delivered. The pump casing comprises at least two branches (branch connections or simply connections), in particular two suction-side inlets and a delivery-side outlet. This means that the impeller sucks a fluid preferably from at least one of the two inlets and delivers it to the delivery-side outlet. A movable valve element which is movable between at least two switching positions, in which the flow paths through the two branches, in particular the two inlets are open to a different extent, is arranged in the pump casing. This means that the two branches or inlets are opened to a differently wide extent and thus the flow cross sections of the branches or inlets change, by way of changing the switching position of the valve element. In the simplest case, one can provide a pure switch-over, wherein in one of the two switching positions a first branch or inlet is opened and a second branch or inlet is closed, whereas in the second switching position the first branch or inlet is closed and the second branch or inlet is opened. However, it is also conceivable for one or more switching positions to be provided, in which switching positions not one of the branches or inlets is completely closed, but merely the opening degree of the two branches or inlets to one another is changed, so that in a first switching position for example the first branch or inlet is opened to a greater extent than in a second switching position. A mixing ratio of the flows through the first and the second inlet between the two switching positions could therefore be changed by way of moving the valve element, i.e. the valve element could act as an adjustable mixing valve.
According to the invention, the design of the valve element and its arrangement in the pump casing is such that it is situated in the pump casing between the suction side and the delivery side of the centrifugal pump assembly and separates these from one another. The valve element is preferably arranged such that its separates a suction chamber which is connected to a suction side of the impeller and into which the two inlets preferably run out, from a delivery chamber which is in connection with the delivery side of the impeller and preferably with a branch as the outlet. This means that the valve element is adjacent to the suction chamber as well as to the delivery chamber. The valve element therefore preferably comprises a side which faces the suction chamber and which comes into contact with the fluid in the suction chamber, and a side which faces the delivery chamber, comes into contact with the pressure in the delivery chamber and is subjected to the pressure in the delivery chamber. Due to the fact that the valve element is adjacent to the delivery side as well as to the suction side, on the one hand it is possible to utilize pressure differences between both sides for moving the valve element. On the other hand, further forces which act in the delivery chamber and/or in the suction chamber, in particular flow forces of the flowing fluid can be utilized to actuate the valve element. In particular, it is possible to use the forces prevailing in the delivery chamber and thereby to carry out a switching function at the suction side.
According to the invention, the valve element is mechanically and/or hydraulically coupled to the drive motor for at least a movement between the at least two switching positions. This coupling is assisted by the arrangement of the valve element between the delivery chamber and the suction chamber. At the one side, the valve element can interact with the two inlets in the suction chamber, in order to change the flow paths through these two inlets in the at least two switching positions. On the other side, the valve element directly faces the delivery chamber which is to say has a side which delimits the delivery chamber and on which the mechanical and/or hydraulic coupling can engage for moving the valve element. Complicated mechanisms for coupling an onflow element which is situated in the pressure chamber, to a valve element which is situated in the suction chamber, can be avoided in this manner. In contrast, it is possible to subject the valve element to force directly in the delivery chamber, in order to move it between the switching positions. The valve element thus preferably comprises force engagement elements or force engagement surfaces which face the delivery chamber and upon which the mechanical and/or hydraulic coupling engages.
The hydraulic coupling between the drive motor and valve element can be effected particularly preferably via the fluid located in the delivery chamber. The fluid is brought into motion for example by the impeller itself and transmits this movement onto the valve element. This can be effected for example by way of friction forces which prevail between the valve element and the fluid. In particular, a friction of the fluid which flows in the delivery chamber, said friction being at the walls which delimit the delivery chamber and prevailing in the delivery chamber, can be utilized in order to move the valve element. The valve element can thus be moved at its side which faces the delivery chamber, via the friction of a fluid flow which occurs there. The movement of the valve element can therefore be accomplished by way of the energy which is otherwise lost due to friction.
Particularly preferably, the valve element is rotatable between the at least two switching positions. This permits a particularly simple movement coupling since a rotation movement is produced by the drive motor in any case. Thus for example a flow which rotates in the delivery chamber can act upon the valve element and move this in a rotating manner.
The rotation axis, about which the valve element is rotatable usefully extends parallel to the rotation axis of the impeller and further preferably in a manner aligned to the rotation axis of the impeller, i.e. preferably essentially in the extension of the rotation axis of the impeller. One therefore succeeds in the impeller or the rotor of the drive motor as well as the valve element rotating about the same axis. A very simple hydraulic and/or mechanical coupling between the valve element and the drive motor or impeller is therefore possible. Preferably, no gear elements whatsoever are necessary, i.e. one can make do without gearwheels, levers or the like.
Further preferably, the valve element is rotatably mounted in its center and in particular is rotatably mounted in the pump casing independently of the impeller. Here, the valve element is further preferably configured such that in at least one position it is in contact with the pump casing merely via the central mounting and possibly necessary restoring elements (e.g. restoring springs) and otherwise can freely rotate about this central mounting. The central mounting is preferably configured such that the radius (outer radius) of the bearing (mounting) surfaces is preferably less than a third, further preferably less than a quarter of the radius of the outer periphery of the valve element. A very easy rotatability of the valve element by forces which engage outside the mounting is achieved by way of this, since these forces act upon the mounting via a comparatively long lever. A particularly easy-motion mounting of the valve element permits this element to be able to be moved between the at least two switching positions by way of comparatively small forces. This for example favors a hydraulic coupling between the drive motor and the valve element.
Further preferably, the valve element is rotatably mounted in the inside of the pump casing in a space which is filled with a fluid to be delivered or with a liquid to be delivered. This means that the mounting is configured in a “wet” manner, so that the mounting can be lubricated by the fluid itself. Moreover, no sealed shaft feed-throughs through the pump casing to the outside are necessary. Despite this, the mounting in the inside of the pump casing can further preferably be sealed off with respect to the surrounding fluid by way of seals. However, such a sealing can be configured such that it is not hermetically tight, but lets through a certain small quantity of fluid which can then serve for example for the lubrication of the bearing. Here, contaminations can however be held back by the seal and one can therefore prevent contamination from entering into the mounting. For this, a sealing gap in the seal is preferably dimensioned such that the fluid to be delivered, e.g. water can pass through the sealing gap, but contamination such as particles are however held back. The mounting can moreover be preferably pre-lubricated, in particular also permanently lubricated. This means that a lubricant can firstly be brought into the mounting, said lubricant in the course of the operating time possibly being diluted and/or replaced by the fluid in the inside of the pump casing.
According to a further particular embodiment of the invention, the valve element is configured and arranged in a manner such that it is movable between the at least two switching positions along a first movement path and is additionally movable in a second movement path which runs in an angled manner to the first movement path. Here, the first movement path is preferably a rotation movement about a rotation axis as has been described above. The second movement path is preferably a movement path which runs in a linear manner, in particular along the rotation axis or parallel to the rotation axis of the valve element. Along the second movement path, the valve element is preferably movable between a first position, in which it is distanced to at least one contact surface (bearing surface), and a second position, in which it is in bearing contact with this contact surface. In the first position, the valve element is preferably freely rotatable about a mounting in the previously described manner. In the second position, it preferably comes to bear on the contact surface which in particular can be formed on the pump casing. The further rotation movement can be prevented and/or a sealing realized by way of this bearing contact.
According to a further preferred embodiment, at least one damping means can be provided, said damping means being connected to the valve element or interacting with it and being configured in a manner such that a movement of the valve element along the second movement path is damped or delayed. Here, the damping can act given a movement from the first position into the second position and/or given a movement from the second position into the first position. An action or effect is preferably given at least with the movement from the second position into the first position. One succeeds in a disengagement from the at least one contact surface being delayed and the valve element therefore being held for longer in a fixed, non-rotatable position by way of this. By way of this, if the valve element has been moved by the drive motor into a desired switching position, one can succeed in the valve element remaining in the previously assumed position after switching off and reassuming operation of the drive motor in the reverse direction, inasmuch as the drive motor is put into operation again in a sufficiently rapid manner. A rapid pressure build up in the delivery chamber can be achieved by way of the rapid starting operation, and this pressure build-up holds the valve element in bearing contact against the contact surface. On account of the damping, it is ensured here that a pressure can build up before the valve element gets into its freely rotatable condition.
The second movement path of the valve element preferably runs parallel to or along the rotation axis of the impeller which, as described above, is further preferably aligned with the rotation axis of the valve element.
According to another possible form of the invention, an end position of the movement of the valve element along the second path of movement, which preferably runs parallel to the axis of rotation of the impeller, is defined by a stop at the axial end of a rotor shaft of the drive motor. I.e., in an end position of the movement of the valve element along the second movement path, the valve element preferably comes into contact with the axial front end of the rotor shaft, so that the movement in this direction is limited by the stop on the rotor shaft.
According to a further preferred embodiment, the valve element can be subjected to a restoring force from a restoring element, for example a restoring spring, said force acting along the second movement path and preferably in the direction of the first position. The restoring elements seeks to move the valve element back into an initial position, wherein the initial position is preferably the first position, in which further preferably the valve element is freely rotatable. One can therefore succeed in the valve element moving back into the first position by way of the restoring element after the fading of the forces and moments which are produced by the impeller when the drive motor is switched off.
Further preferably, the valve element comprises a pressing (pressure) surface which faces the delivery chamber and upon which the pressure prevailing in the delivery chamber acts in a manner such that the valve element is subjected to a pressing force along the second movement path, said pressing force preferably acting in the direction of the second position. The pressing force therefore preferably acts counter to the restoring force. By way of this design, given a pressure build-up in the delivery chamber, caused by way of rotation of the impeller, one succeeds in this pressure, when it reaches a sufficient magnitude, moving the valve element into its second position, in which it preferably comes into bearing contact with a contact surface. A pressure force which is caused by the centrifugal pump assembly itself can therefore be used to move the valve element into a certain position. If the drive motor is stopped and the pressure prevailing in the delivery chamber drops again, the valve element is then preferably moved back again into its first position by a restoring element.
Preferably, the described at least one contact surface is at least one sealing surface. In particular, this can be a sealing surface which is situated such that delivery (pressure) region is sealed with respect to the suction region by way of the valve element bearing on the sealing surface. Alternatively or additionally, at least one sealing surface can be provided and situated in a manner such that one of the branches and in particular one of the inlets is sealed with respect to the suction chamber by way of the valve element bearing on this sealing surface. This inlet is then preferably sealingly closed with respect to the suction chamber, so that the centrifugal pump assembly sucks fluid through the other inlet. Since the valve element is only in sealing contact with the sealing surface or surfaces in the second position in the case of this design, one succeeds in the sealing surfaces being able to disengage in the first position and the friction forces prevailing on the valve element being reduced in the first position, so that in the first position this element can be easily moved between its at least two switching positions.
The at least one contact surface preferably extends in an angled manner to the second movement path, i.e. a force which prevails in the direction of the movement path can lead to a pressing force upon the contact surface. The valve element can therefore be pressed against the contact surface and in particular a sealing surface for sealing, by such a pressing force, in particular by a pressing force which acts along the second movement path and which is caused by the pressure prevailing in the delivery chamber.
As described above, the valve element is mechanically and/or hydraulically coupled to the drive motor for its movement. The valve element can thus be moved between the at least two switching positions by way of the drive motor, wherein further preferably the valve element is moved into one of the two switching positions in a manner dependent on the rotation direction of the drive motor. For this, a stop which prevents a further movement of the valve element in the same direction can be provided in each of the switching positions.
According to a first embodiment, the drive motor can merely be put into operation in the desired rotation direction depending on the desired switching position of the valve element, wherein different efficiencies for the two rotation directions can be achieved depending on the design of the impeller.
According to a particular embodiment of the invention, it is however also possible to utilize a rotation direction change of the drive motor merely for moving the valve element between the switching positions and to always use a preferred rotation direction for delivery independently of the switching position.
Given a suitable activation of the drive motor and of the delay of the movement of the valve element in the second movement direction, said delay having been described above, one can succeed e.g. in the valve element being firstly moved by the drive motor into a first switching position by way of the drive motor being rotated in the direction of this switching position. Here, the valve element is preferably moved into its second position by way of the pressure which builds up in the delivery chamber. If the drive motor is then subsequently switched off and very rapidly rotated into the opposite movement direction, one can succeed in a pressure being built up again in such a rapid manner in the delivery chamber by way of rotation of the impeller in the other movement direction, that the valve element is not able to be moved completely at all into the freely rotatable first position due to the described damping or delay, and therefore remaining in the previously assumed switching position, even if the impeller is subsequently rotated by the drive motor in the direction of the second switching position in the opposite rotation direction.
According to a further preferred embodiment of the invention, a force generating means which exerts a force in the direction of one of the at least two switching positions upon the at least one valve element is present, wherein the force is preferably a spring force, a magnetic force and/or the gravitational force. One can make do without a rotation direction change of the drive motor by way of such a force generating means. The valve element can thus be moved into one of the two switching positions by way of the drive motor and then, on switching off the drive motor, can be moved back again into the other switching position by the force generating means, said other switching position representing an initial position. The drive motor can therefore be configured such that in this initial position, it can be put into operation in such a rapid manner that a pressure builds up in the delivery chamber, said pressure pressing the valve element along the second movement path against the contact surface before the valve element can be moved into its second switching position by a flow building up in the delivery chamber. If the drive motor is brought into operation in an accordingly slow manner, then the flow which moves the valve element into the second switching position can firstly build up before the pressure is adequately large to press the valve element along the second movement path against the contact surface. This can be achieved by way of a suitable activation (control) of the drive motor via a control device which activates the drive motor.
For the coupling between the valve element and the drive motor, the valve element is preferably configured such that it is movable by way of a fluid flow which runs in the delivery chamber in the rotation direction of the impeller and/or that the valve element for its movement is coupled to the impeller or to a shaft which drives the impeller, via a coupling which is preferably releasable in a pressure-dependent and/or speed-dependent and/or rotation-direction-dependent manner. The propulsion via the fluid flow which rotates in the delivery chamber can preferably be effected in a manner such that this fluid flow engages on a surface of the valve element which faces the delivery chamber by way of friction forces. This surface of the valve element can be additionally provided with catches, in particular with blades. Such blades can further preferably simultaneously serve as guide vanes in order to deflect the flow which exits radially out of the impeller, into a desired direction. As long as the impeller is freely rotatable, such a flow can also engage at the suction side and cause a rotation of the valve element. For this, in particular the inlets at the suction side or in the suction chamber can be placed such that they direct the flow in the suction chamber such that they assist in a rotation or movement of the valve element into a desired direction. For this, the valve element according to a particular embodiment can also be provided with corresponding catch elements or blades on the surface which faces the suction side, upon which catch elements or blades a flow in the suction chamber can act for the movement of the valve element. The surface of the valve element which faces the delivery chamber is preferably configured in such large manner that an outer diameter of this surface of the valve element is at least twice to five times as large as the diameter of the suction port of the impeller, so that an adequate surface is available for the engagement of the flow. The surface of the valve element which faces the delivery chamber therefore surrounds the suction port in a preferably annular manner.
According to an alternative embodiment, the design and arrangement of the at least one valve element is such that a flow which is produced by the impeller, in the delivery chamber acts upon the valve element for its movement between the at least two switching positions and the suction chamber is configured in a manner such that the flow which prevails there exerts no force upon the valve element in the movement direction between the switching positions. This means that according to this embodiment, the valve element at its side which faces the suction chamber is configured as smoothly as possible and without force engagement surfaces, upon which a flow could act. One prevents the flow or the fluid in the suction chamber from braking or preventing the movement of the valve element between the switching positions by way of this design.
A mechanical coupling by way of a suitable coupling can be provided alternatively or additionally to the described hydraulic coupling of the valve element and the impeller or drive motor. Here, the coupling can act in a frictional and/or positive manner. The coupling is preferably configured such that it can be mechanically disengaged. This can be effected for example by way of the movement of the valve element along the second movement path, as has been described above. A pressure-dependently releasable coupling would thus be created. Alternatively or additionally, a design which is releasable in a speed-dependent manner could also be realized, for example by way of a lubrication film forming between the coupling surfaces given an adequately high speed, said lubrication film lifting the frictional coupling. Given an adequately high speed, such a design would overcome the friction between the coupling surfaces in the manner of a plain bearing. A coupling acting in a manner dependent on the rotation direction could be realized for example by way of suitably configured catches/drivers which only positively engage in one rotation direction and slide along one another in the opposite rotation direction. This could be a design in the manner of a pawl or a ratchet. With such a design, the valve element would always move into the desired switching position only in one rotation direction of the drive motor. After reaching the switching position, the drive motor could then be put into operation in the opposite rotation direction, in order to start delivery operation of the centrifugal pump assembly. The coupling then disengages in this opposite rotation direction and the valve element can thus remain in the previously assumed switching position.
According to a further preferred embodiment of the invention, the valve element comprises an opening, via which the suction chamber is in connection with a suction port of the impeller. Here, the suction port of the impeller can be in bearing contact or engagement with the valve element preferably in the peripheral region of the opening, in order to achieve a sealing with respect to the delivery chamber which is delimited by the valve element. The suction port of the impeller can thus be surrounded for example by a collar which engages into the opening of the valve element. Alternatively or additionally, the opening of the valve element can be surrounded by a collar which overlaps with a collar which is on the impeller and which surrounds the suction port. A sealing between the valve element and the suction port can therefore be achieved. The part of the valve element which surrounds the opening can face delivery chamber, which is to say delimit the delivery chamber, in which the impeller rotates. The opposite surface of the valve element faces the suction chamber, so that the valve element separates the suction chamber and delivery chamber from one another in the region which surrounds the suction port of the impeller.
The drive motor is particularly usefully activated via a control device in a manner such that it can be driven in two rotation directions and/or is preferably adjustable in its speed. For this, the control device can comprise a speed controller and in particular a frequency converter for the adjusting/setting the rotation direction and/or the speed. The change of the speed is preferably possible in a manner such that the acceleration on starting up and braking the drive motor can also be varied, in order to realize different courses of acceleration. This means that the control device is configured in a manner such that it can accelerate and/or brake the drive motor to a different extent, for example by way of corresponding ramps for the acceleration and braking being selected. By way of this, it is possible to move the valve element into the desired switching position by way of a suitable rotation of the drive motor in the manners described above and to subsequently go into delivery operation, in which the valve element remains in the previously assumed switching position. Moreover, a speed regulation preferably by way of the control device is possible in the usual manner on delivery operation, in order to be able to operate the centrifugal pump assembly according to desired characteristic curves.
The centrifugal pump assembly according to the invention is preferably a circulation pump assembly, in particular a circulation pump assembly as is applied in heating facilities and/or air-conditioning facilities for circulating a heat transfer medium. Such circulation pump assemblies are preferably configured for delivering water as a heat transfer medium. The electric drive motor is preferably configured as a wet-running electrical drive motor, i.e. a canned motor, concerning which a can or canned pot separates the stator from the rotor so that the rotor rotates in the fluid to be delivered.
The invention is hereinafter described by way of example and by way of the attached figures. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
In the drawings:
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.
The centrifugal pump assembly according to the first embodiment 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.
An electronics casing 16 which contains control electronics or a control device 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.
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 abuts with its outer periphery. In the opposite direction, the movablility is limited by the nut 22, with which the valve element 18 is fastened on the pivot 20. It is to be understood that a different axial fastening of the valve element 18 to the pivot 20 could also be selected instead of the nut 22.
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 connection or delivery branch (delivery nozzle) 27 of the centrifugal pump assembly which forms the outlet of the centrifugal pump assembly. Two suction-side inlets 28 and 30, of which the inlet 28 is connected to a first suction branch 32 and the inlet 30 is connected to the second suction branch 34 of the pump casing 12 run out into the suction chamber 24.
The valve element 18 is configured in a disc-like manner and simultaneously assumes the function of a common deflector plate which separates the suction chamber 24 from the delivery chamber 26. The valve element 18 comprises a central suction opening 26 which comprises a projecting peripheral collar which is engaged with the suction port 38 of the impeller 14 and is essentially in sealing bearing contact with the suction port 38. Facing the impeller 14, the valve element 18 is configured in an essentially smooth manner. The valve element at the side which is away from the impeller 14 comprises two annular sealing surfaces 40 which in this embodiment example are situated on closed, tubular stubs (connection pieces or nozzles). The two annular sealing surfaces 40 are arranged on the sealing element 18 at two diametrically opposite positions with respect to the rotation axis X of this element, so that they can come to sealing bear on the base of the pump casing 12 in the peripheral region of the inlets 28 and 30, so as to close the inlets 28 and 30. Support elements 42 are arranged offset to the sealing surfaces 40 at an angular position of 90° and can likewise come to bear on the peripheral region of the inlets 28, 30, but are distanced to one another such that they do not then close the inlets 28, 30. The inlets 28 and 30 do not lie on the diameter line with respect to the rotation axis X, but on a radially offset straight line, so that on rotation of the valve element 18 about the rotation axis X into a first switching position, the inlet 38 is closed by a sealing surface 40 whilst the support elements 42 lie on the inlet 30 and open this. In a second switching position, the inlet 30 is closed by a sealing surface 40 whilst the support elements 42 bear in the peripheral region of the inlet 28 and open this. The first switching position, in which the inlet 38 is closed and the inlet 30 is opened is represented in
In an idle position, which is to say when the centrifugal pump assembly is not in operation, a spring 48 presses the valve element 18 into released position, in which the outer periphery of the valve element 18 does not sealingly bear on the pump casing 12 and the sealing surfaces 40 do not sealingly bear in the peripheral region of the inlets 28 and 30, so that the valve element 18 can rotate about the axis 20. If the drive motor is now brought into rotation by the control device 17 in the electronics casing 16, so that the impeller 14 rotates, then a peripheral flow which via the friction co-rotates the valve element 18 in its rotation direction is produced in the delivery chamber 26. The control device 17 is configured such that it can drive the drive motor selectively in two rotation directions. The valve element 18 can therefore likewise be moved in two rotation directions about the rotation axis X depending in the rotation direction of the impeller 14, via the flow which is brought into rotation by the impeller 14, since the flow in the peripheral region of the impeller 14 always runs in its rotation direction. The valve element 18 can therefore be rotated between the two switching positions which are limited by the stops 46.
If the impeller 14 rotates at a sufficient speed, then a pressure builds up in the delivery chamber 26 and this pressure produces a pressing force on the surface of the valve element 18 which surrounds the suction opening 36, said pressing force being opposite to the spring force of the spring 48, so that the valve element 18 is moved in the axial direction X against the spring force of the spring 48 such that it comes to sealingly bear at its outer periphery on an annular contact shoulder 50 on the pump casing 12. Depending on the switching position, one of the sealing surfaces 40 simultaneously comes to sealingly bear on the periphery of one of the inlets 28 and 30, so that one of the inlets 28, 30 is closed. The support elements 42 come to bear on the other inlet, so that this inlet remains open and a flow path from this inlet 28, 30 to the suction opening 36 and from there into the inside of the impeller 14 is given. A frictional contact between the valve element 18 and the pump casing 12 is simultaneously created by way of the bearing of the valve element 18 on the contact shoulder 50 and on the sealing surface 40 in the peripheral region of one of the inlets 28, 30. This frictional contact ensures that the valve element 18 is held in the reached switching position. This permits the drive motor to be briefly taken out of operation and to be brought into operation again in the opposite rotation direction without the valve element 18 being rotated. If the switching-off and restarting operation of the motor are effected rapidly enough, then the pressure in the delivery chamber 26 does not reduce to the extent that the valve element 18 can again move in the axial direction into its released position. This permits the impeller to always be driven in its preferred rotation direction, for which the blades are configured, on operation of the centrifugal pump assembly and to only use the opposite rotation direction for moving the valve element 18 in the opposite rotation direction.
The described centrifugal pump assembly according to the first embodiment of the invention can be applied for example in a heating system as is shown in
The second embodiment example according to
The third embodiment example according to
In this embodiment example, the mounting of the valve element 18″ on the pivot 20 is moreover encapsulated by two sleeves 82 and 84, so that these regions are protected from contamination by the delivered fluid and can be possibly pre-lubricated. A very easy-motion mounting is sought after, in order to ensure the easy rotatability of the valve element 18″ by the flow which is caused by the impeller 14. It is to be understood that the mounting can be encapsulated accordingly also in the case of the other embodiment examples which are described here.
The fifth embodiment example according to
The sixth embodiment example according to
Depending on the switching position of the valve element 18e, the opening 62 either comes to lie over the inlet 28′ or the outlet 30′, in order to either open a flow path from the suction branch 32 to the impeller 14 or from the suction branch 34 to the impeller 14. In this embodiment too, the valve element 18e is additionally axially movable along the rotation axis X which is the rotation axis of the impeller 14 and of the valve element 18e. In an idle position, in which the centrifugal pump assembly is not in operation, the valve element 18e is pushed by the spring 48 into a released position, in which the surface of the valve element 18e which is away from the impeller 14 is distanced to the base of the pump casing 12, so that the valve element 18e can be rotated to and fro about the axis 94 in an essentially free manner between the stops which are formed by the pin 68 and the groove 70.
With this embodiment example, the rotation of the valve element 18e is again effected via the impeller 14, but here a mechanical coupling is provided, said coupling being realized by way of the impeller 14 with its region which surrounds the suction port 38 coming to frictionally bear on the periphery of the suction opening 36e. The valve element 18e is therefore co-rotated with the impeller 14 until the pin 68 reaches a stop. The coupling then disengages due to slip. Then, with an increasing pressure in the delivery chamber 26, the valve element 18e is moved axially into its bearing position as described above, wherein the coupling disengages from the impeller 14, so that the impeller 14 can then rotate in an essentially frictionless manner.
The seventh embodiment example according to
The eighth embodiment according to
In a first switching position which is shown in
The movement of the valve element 18g is effected via the drive of the impeller 14. At the start, the rotor shaft 8 bears non-positively on the inner periphery of the ring segments 10 and co-rotates these and thus the valve element 18g. Stops for both switching positions can be formed in the pump casing 12 in the manner described above. When the valve element 18g reaches one of these stops, then the pump shaft 8 slides through in the inside of the ring segments 100. Moreover, a lubrication film forms between the outer periphery of the rotor shaft 8 and the inner surfaces of the ring segments 100 in the manner of a plain bearing, given an increasing speed of the rotor shaft 8, so that the rotor shaft 8 can then rotate in an essentially frictionless manner in the inside of the ring segments 100. This means that for adjusting or actuating the valve element 18g between its two switching positions, the drive motor is moved by the control device 17 preferably at a lower speed than the speed at which the impeller 14 is rotated on operation. The drive motor can be driven in two rotation directions in the manner described above, for moving the valve element 18g to and fro, wherein again after reaching the desired switching position, by way of a rapid speed increase, one can succeed in the valve element 18g remaining in the previously reached switching position on account of the pressure in the delivery chamber 26 and the bearing contact of the valve element on the base of the pump casing 12, in the manner described above.
With regard to the ninth and tenth embodiment according to
With regard to the ninth embodiment according to
The motor casing 2 with the electronics casing 16 corresponds to the previously described embodiment. The pump casing 12 is constructed in essentially the same manner as the pump casing according to the first embodiment according to
The pump casing 12 comprises two suction branches 32 and 34, of which the suction branch 32 runs out at an inlet 28h and the suction branch 34 at an inlet 30h, 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 76h of the valve element 18h in its base comprises an arched opening 112 which extends essentially over 90°.
Such a functionality can be applied for example in a hydraulic system as is shown in
The tenth embodiment example according to
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 18h, 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.
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 28h and 30h, into the suction chamber 24. The various switching positions are explained by way of
Such a centrifugal pump assembly can be applied for example in a heating system as is shown in
When the valve element 18i is located in the first switching position represented in
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
It is to be understood that the various previously described embodiments can be combined with one another in a different manner. Thus the different described drive modes of the valve element can be essentially arbitrarily combined with different geometric designs of the valve element as have likewise been described above. The different valve functionalities (for example mixing and switching-over) can likewise be realized and combined with different drive modes. These different combination possibilities which are to be derived from the preceding embodiment examples are expressly encompassed by the invention.
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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 17160830.0 | Mar 2017 | EP | regional |
This application is a United States National Phase Application of International Application PCT/EP2018/056207, filed Mar. 13, 2018, and claims the benefit of priority under 35 U.S.C. § 119 of European Application 17 160 830.0, filed Mar. 14, 2017, the entire contents of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2018/056207 | 3/13/2018 | WO | 00 |
