Pump

Abstract

A circulating pump with an impeller disposed in a pump housing, by which a fluid can be delivered from a pump inlet of the pump housing to a pump outlet of the pump housing. The circulating pump includes an electric motor, the rotor of which is mechanically coupled to the impeller via a shaft such that that the impeller can be placed into an appropriate rotating movement by rotation of the rotor, and cools the rotor of the electric motor by a thermosiphon in the shaft, wherein the impeller serves as a heat sink for a working medium of the thermosiphon.

1 - 14 . (canceled) 
     
     
         15 . A pump, in particular a circulating pump, comprising:
 a pump housing having a pump inlet and a pump outlet;   an impeller in said pump housing by which a fluid can be delivered from the pump inlet to the pump outlet;   an electric motor having a rotor mechanically coupled to said impeller via a shaft, whereby rotation of the rotor causes rotation of said impeller; and   a thermosiphon in the shaft, cooling the rotor of the electric motor, said impeller serving as a heat sink for a working medium of said thermosiphon.   
     
     
         16 . The pump as claimed in  claim 15 , wherein said thermosiphon in the shaft is formed by a recess, extending in a longitudinal direction, in which the working medium circulates owing to a change in state of aggregation between liquid and gaseous. 
     
     
         17 . The pump as claimed in  claim 16 , wherein the recess extends over an entire width of the rotor of said electric motor. 
     
     
         18 . The pump as claimed in  claim 17 ,
 wherein said electric motor further includes bearings, and   wherein the recess is formed in a region of the bearings of said electric motor.   
     
     
         19 . The pump as claimed in  claim 18 ,
 wherein the shaft has a central section and an end section, fixedly connected to the central section, to which said impeller is fastened, and   wherein the recess includes a cylindrical recess in the central section of the shaft and a conical recess in the end section of the shaft.   
     
     
         20 . The pump as claimed in  claim 19 ,
 further comprising a housing part in which said electric motor and at least part of the central section of the shaft are arranged in a fluid tight manner, and   wherein the end section is formed outside said housing part.   
     
     
         21 . The pump as claimed in  claim 20 ,
 wherein said housing part includes a passage opening for the shaft, and   wherein said pump further comprises a seal, surrounding the end section and the central section of the shaft on an outer circumferential side, arranged outside said housing part and fitting snugly onto the passage opening for the shaft.   
     
     
         22 . The pump as claimed in  claim 21 , further comprising a device with spokes extending radially from a central hub, provided in the conical recess of the end section of the shaft to improve formation of a film of condensate of the working medium on a conical wall of the end section. 
     
     
         23 . The pump as claimed in  claim 22 , wherein each of the shaft and the cylindrical recess has a diameter and a ratio of the diameter of the cylindrical recess to the diameter of the shaft provides for at least a predetermined torque to be transmitted to said impeller. 
     
     
         24 . The pump as claimed in  claim 23 , wherein the shaft has a rough wall bounding the recess. 
     
     
         25 . The pump as claimed in  claim 24 , wherein the working medium is placed into the recess under vacuum and is maintained in the recess permanently without any loss by said seal. 
     
     
         26 . The pump as claimed in  claim 25 , wherein the working medium has an evaporation temperature of less than 100° C. and is selected from a group consisting of water, R124a refrigerant, FC72 refrigerant, R600a refrigerant, and isobutane. 
     
     
         27 . The pump as claimed in  claim 16 , wherein the shaft has an end outside the housing part, opposite the end section, with a hub provided for connection to a fan wheel for cooling the electric motor. 
     
     
         28 . The pump as claimed in  claim 27 , wherein, in an installation, the shaft is mounted horizontally or is mounted with respect to a direction of gravitational force, said impeller on the end section of the shaft is located higher than the central section of the shaft.