GB1312964A - Motor pump units - Google Patents

Abstract

1312964 Cooling electric motors NIKKISO CO Ltd 27 May 1970 [29 May 1969] 25396/70 Heading H2A [Also in Division F1] In a motor-driven pump in which liquid is circulated from the pump outlet 16, Fig. 1, via a pipe 18 to flow through bearings 22, 25 and between the rotor and stator of the motor to lubricate the bearings and cool the motor, the housing 32 for the bearing 25 is, according to a known arrangement, formed with a radially extending portion 33 to afford a rear wall of the impeller chamber and provided with orifices 26 for the return of the liquid to the impeller chamber to balance the impeller thrust. According to the invention, the single member 32 is replaced by three members, viz., a bearing housing 64, Fig. 3, an orifice disc 78 provided with the orifices, and an adaptor 50 connecting the bearing housing and the orifice disc. Instead of engaging an inner periphery 90 of the pump easing 86, the orifice disc 78 may be secured to the adaptor 50 only or it may be modified for engagement with an end face 92 of the pump casing. The end portion 72 of the bearing housing 64 may be radially extended so that it abuts the whole end face of the end closure plate 54 of the stator housing 98. As shown, the adaptor 50 may afford an auxiliary pump chamber 62 accommodating an auxiliary impeller 60 providing an independent circulation to the rear bearing 22 via a pipe 68. A guide disc 70 is in this case provided so that the liquid returning through orifices 76 is directed towards the suction side of the impeller 60. If the pumped liquid is too hot to cool the motor, the stator housing 98 may be surrounded by a jacket through which a cooling medium is circulated. The pipe conveying the liquid circulated from the pump outlet may then be coiled within the jacket.