Pump assembly

Abstract

A pump assembly includes an electric drive motor (4, 6), an impeller, driven by the drive motor (4, 6), and a valve device (18) situated in a flow path through the pump assembly, which is movable between a first and a second switching position. The valve device (18) is coupled to the drive motor via a first coupling such that a movement of the drive motor (4, 6) is transmitted onto the valve device (18) and the valve device is movable from the first into the second switching position by rotation movement of the drive motor. The first coupling is releasable by way of increasing the speed of the drive motor (4, 6) and/or increasing the pressure at the outlet side of the impeller and/or by way of slip, such that the coupling between the drive motor (4, 6) and the valve device (18) is reduced or lifted.

1 . A pump assembly comprising:
 an electric drive motor;   at least one impeller which is driven by the drive motor; and   at least one valve device which is situated in a flow path through the pump assembly and which is movable at least between a first switching position and a second switching position, wherein the valve device is coupled to the drive motor via a first coupling such that a movement of the drive motor is transmitted onto the valve device and the valve device is movable from the first into the second switching position by way of a rotation movement of the drive motor and the first coupling is releasable by way of increasing the speed of the drive motor and/or increasing pressure at the outlet side of the impeller and/or by way of slip, such that the coupling between the drive motor and the valve device is reduced or lifted.   
     
     
         2 . A pump assembly according to  claim 1 , wherein a second releasable coupling is provided between at least one movable part of the valve device and a pump casing which surrounds the impeller, said second releasable coupling being movable from a released, first coupling position into a holding, second coupling position by way of the pressure at the outlet side of the impeller. 
     
     
         3 . A pump assembly according to  claim 2 , wherein the first and the second coupling are configured such that the first coupling in a first coupling released position has a lower holding force than the second coupling in a second coupling holding position and the first coupling in a first coupling coupled position has a greater holding force than the second coupling in a second coupling released position. 
     
     
         4 . A pump assembly according to  claim 1 , wherein on operation of the pump assembly, the drive motor produces a torque which is larger than the holding force of the first coupling in a first coupling coupled position. 
     
     
         5 . A pump assembly according to  claim 1 , wherein the valve device is configured as a switch-over valve which permits a switching-over between two flow paths and/or is configured as a mixing device, in which fluid is mixed from two flow paths, wherein the mixing device is configured such that the mixing ratio is different in the two switching positions. 
     
     
         6 . A pump assembly according to  claim 1 , wherein the valve device has a valve function in a flow path at the suction side of the impeller and/or in a flow path at the delivery side of the impeller. 
     
     
         7 . A pump assembly according to  claim 1 , wherein the valve device comprises at least one movable valve element as well as stop elements which define the first and the second switching position and of which at least one is position adjustable. 
     
     
         8 . A pump assembly according to  claim 1 , wherein the valve device comprises at least one movable valve element which interacts with two valve openings such that in the first switching position of the valve device, a first valve opening is covered by the valve element to a greater extent than in the second switching position and in the second switching position a second valve opening is covered to a greater extent than in the first switching position. 
     
     
         9 . A pump assembly according to  claim 1 , wherein the valve device comprises a movable valve element which comprises at least one sealing surface and a pressure surface, wherein the pressure surface is connected to a delivery chamber which surrounds the impeller, such that the valve element is pressed with the sealing surface against a contact surface by way of the pressure which acts upon the pressure surface, wherein the contact surface forms a valve seat. 
     
     
         10 . A pump assembly according to  claim 1 , wherein the valve device comprises a rotatable valve element which via the first coupling is releasably coupled to a rotor of the drive motor, wherein the rotation axis of the valve element is aligned with the rotation axis of the drive motor. 
     
     
         11 . A pump assembly according to  claim 1 , wherein the drive motor driveable in two rotation directions and the valve device is configured such that the first switching position is achieved by the drive of the drive motor in a first rotation direction and the second switching position is reached by the drive of the drive motor in a second rotation direction. 
     
     
         12 . A pump assembly according to  claim 2 , wherein the first and/or the second coupling is a friction coupling, a magnetic coupling and/or a hydraulic coupling, which has slip. 
     
     
         13 . A pump assembly according to  claim 1 , wherein the first coupling comprises at least one coupling element which is movable between a coupled and a released position, wherein the movement direction between the coupled and the released position runs transversely to a force direction of the force which is to be transmitted by the coupling onto the valve device. 
     
     
         14 . A pump assembly according to  claim 13 , wherein a valve element of the valve device forms the movable coupling element. 
     
     
         15 . A pump assembly according to  claim 13 , wherein the coupling element is subjected to a biasing force via a biasing element, said biasing force forcing the coupling element into the coupled position. 
     
     
         16 . A pump assembly according to  claim 15 , wherein the coupling element comprises a pressure surface, the connection of said pressure surface to a delivery chamber which surrounds the impeller and the arrangement of said pressure surface being such that a pressure acting upon the pressure surface produces a force which is directed oppositely to the biasing force. 
     
     
         17 . A pump assembly according to  claim 13 , wherein the coupling element comprises a coupling surface which in the coupled condition is in frictional contact with a counter coupling surface, and that the coupling surface and the counter coupling surface are configured and surrounded by a lubricant, such that a lubricant film which overcomes the frictional contact forms between the coupling surface and the counter coupling surface on increasing the speed of the drive motor.