GB1351826A - Lubricating cooling and balancing of pump and motor units - Google Patents

Abstract

1351826 Cooling/lubricating dynamo-electric machines J C CARTER CO 29 Nov 1971 55354/71 Heading H2 [Also in Division F1] A pump and motor unit particularly for liquified gas has the pump and motor respectively housed in pump and motor compartments, means for bleeding off some of the pumped liquid on the discharge side of the pump, and means for flowing a first part of the bled-off liquid through the motor compartment and subsequently returning it to the discharge side the pump and for flowing a second part to the pump inlet through thrust load relief means. The bled-off liquid may be used to lubricate and cool the motor and bearings provided for the motor shaft and to reduce end thrust on the bearings. In a submersible unit induction impeller 34 (Fig. 4) and centrifugal pump impeller 36 are both keyed to hollow shaft 43, the induction impeller discharging to the suction side of impeller 36 and into annular chamber 37 from which liquid is returned through a release valve 38 to the tank in which the unit is submerged. Impeller 36 discharges into a chamber 45, through diffuser 47a to an annular chamber 48a Shaft 43 is mounted on bearings 53, 70 and carries motor rotor 61. Chamber 46 communicates with outlet 82 through openings (81) (Fig. 6, not shown) in top plate 66. Liquid is bled from ports 83 and is conducted via filters 85 and bores 84 to radial passages 78 in the plate 66. Part of this liquid is passed through openings 80 in plate 66 to the motor compartment and a second part flows to an annular chamber 79 where it is divided, a minor portion flowing into a chamber 72 and then via chamber 76 to the hollow shaft 43. The pressure in chamber 72 causes the drum 71 to be lifted thereby lifting the shaft to reduce the load on the bearings 70. The major portion of the liquid divided in chamber 79 flows via the bearing 70 into the motor compartment. The liquid flowing through the shaft 43 is discharged into the suction port 32a. The major part after flowing through the motor divides, one portion flowing through the bearings 53 to radial impeller blades 44 formed on the back of impeller disc 42, which discharge the pumpage via passage 88 into the discharge chamber 45. The second portion of pumpage from the motor flows through passages 87a in pools 87 and through passages 88 to the chamber 45. In an alternative embodiment (Figs. 1, 8, 9, not shown) the motor housing 47 does not extend the full length of the unit, the annular chamber thus extending only partly up the casing and the pumped liquid filling the whole of the casing 31 above the motor housing. A foot valve 14 is also provided to close the pump inlet until the unit 20 is properly installed.