Centrifugal pump assembly

Abstract

A centrifugal pump assembly includes an electric drive motor and an impeller (38; 38′), driven rotationally by the electric drive motor and arranged in a pump housing (24; 24′). The pump housing includes a first suction duct (46; 46′) that forms a first flow path from a first suction connector (44; 44′) to a suction side of the impeller. The pump housing includes a receiving chamber (50; 50′) which intersects the first suction duct, is connected to a second suction connector (58; 82; 110; 116), and in an interior includes a movable valve element (64; 90; 100; 128) connected to an actuating drive (76; 94; 105; 124) and configured to, with the movement of the valve element, change a cross-sectional ratio between the first flow path which extends from the first suction connector and a second flow path which extends from the second suction connector.

1 . A centrifugal pump assembly comprising:
 an electrical drive motor;   at least one impeller which is rotatingly driven by the electric motor;   a pump casing, wherein the at least one impeller is arranged in the pump casing, a first suction channel is formed in the pump casing, said first suction channel forming a first flow path from a first suction connection piece to the suction side of the impeller, and the pump casing comprises a receiving space which intersects the first suction channel and which receiving space is connected to a second suction connection piece and which receiving space has an interior;   at least one movable valve element arranged in the interior of the receiving space;   an actuator, said valve element being connected to the actuator and being configured such that a cross-sectional ratio between the first flow path which extends from the first suction connection piece, and a second flow path which extends from the second suction connection piece, is changed by way of a movement of the valve element.   
     
     
         2 . A centrifugal pump assembly according to  claim 1 , wherein the actuator comprises one of an electrical, thermal or hydraulic actuator. 
     
     
         3 . A centrifugal pump assembly according to  2 , wherein the actuator is a hydraulic actuator which comprises:
 a pressure connection, via which an exit-side pressure of the impeller acts upon the at least one valve element; and   a biasing element exerting a biasing force which is directed opposite to a pressing force which is produced by the exit-side pressure.   
     
     
         4 . A centrifugal pump assembly according to  claim 2 , wherein the actuator is a thermal actuator arranged such that the thermal actuator moves the at least one valve element in dependence on a temperature in one of the two flow paths. 
     
     
         5 . A centrifugal pump assembly according to  claim 1 , wherein the first and the second flow path run out into the receiving space and a section of the first suction channel forms a flow path from the receiving space to the suction side of the at least one impeller. 
     
     
         6 . A centrifugal pump assembly according to  claim 1 , wherein the receiving space is delimited by a wall which is configured as one piece with at least one further part of the pump casing, wherein the wall which delimits the receiving space and the complete pump casing are configured as one piece of metal or plastic. 
     
     
         7 . A centrifugal pump assembly according to  claim 1 , wherein the receiving space comprises a tubular basic shape with a longitudinal axis that extends transversely and to a plane, in which a rotation axis of the drive motor is situated. 
     
     
         8 . A centrifugal pump assembly according to  claim 1 , wherein:
 the first suction connection piece and a delivery connection piece which is formed on the pump casing are directed opposite one another in a direction of a common installation axis;   the receiving space has a tubular basic shape; and   a longitudinal axis of the receiving space extends transversely to a plane, in which this installation axis is situated.   
     
     
         9 . A centrifugal pump assembly according to  claim 1 , wherein:
 a valve insert is inserted into the receiving space; and   in an inside of the valve insert the at least one valve element is movably guided.   
     
     
         10 . A centrifugal pump assembly according to  claim 1 , wherein a valve insert is inserted into the receiving space, said valve insert interrupting the first suction channel such that a first section of the first suction channel forms the first flow path and a second section of the first suction channel forms a flow path from the receiving space to the suction side of the impeller. 
     
     
         11 . A centrifugal pump assembly according to  claim 1 , wherein the at least one valve element is movable in a direction of a longitudinal axis of the receiving space. 
     
     
         12 . A centrifugal pump assembly according to  claim 1 , wherein the first and/or the second flow path end in a valve seat, with which the at least one valve element can be brought into bearing contact. 
     
     
         13 . A centrifugal pump assembly according to  claim 1 , wherein:
 the first flow path runs out into a first valve seat;   the second flow path runs out into a second valve seat, and   a flow path branches to a suction side of the impeller between the valve seats;   the at least one valve element comprises two valve surfaces which face the valve seats and which are arranged such that given a movement of the valve element one valve surface distances itself from the one of the valve seats and simultaneously the other valve surface approaches the other valve seat.   
     
     
         14 . A centrifugal pump assembly according to  claim 13 , wherein the valve seats face one another and the at least one valve element is situated between the valve seats. 
     
     
         15 . A centrifugal pump assembly according to  claim 1 , wherein:
 the at least one valve element is configured with a sleeve shape,   the second flow path runs through the inside of the sleeve; and that   the sleeve comprises a wall that comprises an exit opening arranged lying opposite an entry opening of a flow path to a suction side of the impeller such that the exit opening of the sleeve wall is brought to overlap with the entry opening to a different extent by way of a movement of the valve element.   
     
     
         16 . A centrifugal pump assembly according to  claim 15 , wherein the valve element is configured and arranged such that with and outer side of the valve element, depending on a positioning of the valve element closes a flow connection from the first flow path to the entry opening to a different extent. 
     
     
         17 . A centrifugal pump assembly according to  claim 15 , wherein a valve surface which acts in a movement direction of the valve element and which in an end position of the valve element bears on a valve seat such that the second flow path is closed, is formed on the valve element. 
     
     
         18 . A centrifugal pump assembly according to  claim 1 , wherein the receiving space comprises a first opening at a first axial end and a second opening at an opposite second axial end. 
     
     
         19 . A centrifugal pump assembly according to  claim 18 , wherein one of the openings forms the second suction connection piece or is connected to the second suction connection piece, wherein a valve insert which is connected to the second suction connection piece extends outwards out of the opening. 
     
     
         20 . A centrifugal pump assembly according to  claim 18 , wherein one of the openings is closed by a closure element. 
     
     
         21 . A centrifugal pump assembly according to  claim 20 , wherein the actuator is arranged on the closure element and/or an actuation element of the actuator which is connected to the valve element and extends through the closure element into the inside of the receiving space. 
     
     
         22 . A centrifugal pump assembly according to  claim 1 , wherein an actuation element which is connected to the valve element is configured as a pivotable lever which extends transversely to the movement direction of the valve element and preferably extends outwards through a wall of the receiving space and/or of a valve insert which is inserted into the receiving space.