Hermetisch abgeschlossene, zur Foerderung eines Mediums hoeherer Temperatur geeignete elektrische Motorpumpe

785,488. Centrifugal pumps. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. June 24, 1955 [July 1, 1954], No. 18302/55. Class 110 (1). [Also in Group XXXV] In a pump motor, the pumped fluid has access to the rotor space and additional coolant is circulated through the stator core and windings which are in an otherwise sealed compartment. As shown, inlet and outlet apertures 134, 136 provide for the flow of external coolant, e.g. oil, through the stator chamber which is enclosed by main casing 2, end rings 4, 6 and the air gap partition 18, the coolant traversing axial ducts 140, 142 near the stator core peripheries. The rotor has a squirrel-cage winding enclosed by a sheath 40 and is cooled by pumped liquid which seeps through the labyrinth seal 106, the rotor having auxiliary impeller blades for circulating liquid through channels 124, 125 in the lefthand bearing 48. A flanged guide member 146 is provided in the stator compartment to bring the stator coolant into heat-exchange relationship with the liquid in channels 125. The rotor compartment is closed by cover 56 which has normally closed outlets 128, 130 which can be used as vents for trapped air and to drain off the liquid. Seals 90, 98 prevent direct flow between the inlet and discharge sides of the impeller and these consist of a series of thin washers 92, Fig. 3, iriterspaced between heavy rings 94 of inner diameter substantially larger than the inner diameter of washers 92 which is slightly larger than the diameter of the adjacent impeller part. To reduce thrust effects holes 88 are provided in the impeller 72 and the walls 164, 166 of the pump chamber are given an irregular surface by shot blasting, knurling or as shown in Fig. 3 by the addition of slightly overlapping parallel welding beads 162. To inhibit the flow of heat from pump to motor when a hot liquid is being pumped, intervening members 100, 102 provide an area 104 containing dead air or an insulating material such as glass wool.