Patent GB-770520-A (GB)
Title: Improvements in or relating to structures comprising a motor and a pump driven thereby
IPC: F04D29/58
Filed: 1953-12-11
Abstract: 770,520. Centrifugal pumps. HAYWARD TYLER & CO., Ltd., and IVANOFF, A. Dec. 8, 1954 [Dec. 11, 1953], No. 34560/53. Class 110 (1). [Also in Group XXXV] In a pump in which the pump and driving motor are mounted in a common casing to which the liquid being pumped has access, the common casing is in two parts, joined together in a plane of junction between the pump and motor, and when the casing parts are separated, the pump impeller, the rotor and stator of the motor and the shaft and bearings come away as a unit with one of the casing parts, and means are provided between the pump and the plane of junction to keep the latter relatively cool. In the centrifugal pump shown, the pump casing 4 is extended at 22 and 23 to house the driving motor and the driving shaft 2. The motor stator 5 is carried by a shell 8 to which is attached bearing housings 11, 12 which support journal bearings 9, 10 and a thrust bearing 13, all of the tilting-pad type. The shell 8 is attached to the casing part 23 by bolts 25 which also pass through the bearing housing 11. The latter carries a thick disc 18 which conducts heat from the shaft 2 to the casing part 22, where it is carried away by cooling water circulated, by way of pipes 49, 50, through an annular jacket 60. The lower part of the shaft 2 is made hollow to reduce the flow of heat through it. A sleeve 17 which closely surrounds the shaft 2 is welded to the disc 18 and has a flange 19 which engages the inner wall of the casing. Corrugated baffle discs 20 supported by the flange 19 and flat baffle discs 21 secured to the sleeve 17 help to retard the flow of heat towards the motor from the hot liquid being pumped. A disc 16 forming part of the thrust bearing 13 has an axial bore 37 and radial bores 38 to form a centrifugal impeller which pumps cooling liquid which flows to it from an inlet pipe 35 by way of ports 39 in a stationary skirt 33. The cooling liquid expelled through the bores 38 flows to the space above the motor, partly through the bearings 13, 10 and partly through ports 40. After passing through the motor, the cooling liquid flows to an outlet pipe 36 partly through ports 42, 43 and partly through bearing 9, the clearance space between the shaft 2 and sleeve 17, and ports 44. Ports 41 permit some of the cooling liquid which has passed through the motor to flow to the outside of the shell 8. A filter 45, which may be of asbestos, prevents sediment in the pumped liquid from reaching the bearings. After removal of bolts 24, the casing part 23 can be lifted away from the part 22, carrying with it all the inner mechanism. The lower part of the casing may be permanently welded to the associated piping. The discs 20, 21 may be replaced by an annular metal case filled with heat-resisting cement or ceramic material. According to the Provisional Specification, the stationary sleeve is increased in diameter at its top to accommodate part of the lower journal bearing, and the flange at the bottom of the sleeve has a circumferential groove in its periphery to take a sealing element such as a snap ring. The flange is thickened at its periphery to provide a clearance between the major portion of the flange and the lowermost one of the stack of discs. Communication between this clearance and the inside of the sleeve is provided by radial holes through the sleeve. All the baffle discs are of heat-insulating material, and there is one such disc above the thick heat-conducting metal disc. Specification 621,042 is referred to.