GB1320841A - Motor driven pump - Google Patents

Abstract

1320841 Centrifugal pumps MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 4 Jan 1971 [9 Jan 1970 19 Feb 1970(8) 20 Feb 1970] 327/71 Heading F1C [Also in Division H2] A motor-driven pump comprises a cylindrical sleeve 7 sealed at one end to the motor casing 1 and surrounded by the motor stator 9, the interior of the sleeve supporting bearing blocks 11, 12 for a hollow rotor shaft 13 forming a main liquid flow passage and carrying a pump impeller 22 at one end which projects into a pump casing 2, the other end of the sleeve 7 being sealed to an annular end plate 3 held captive at its outer periphery between the motor and pump casings. As shown in Fig.1, the bearing blocks have passages 15, 16 through which some of the liquid drawn through the shaft 13 recirculates to lubricate the bearings before being entrained back into the main flow by a plate 25 with a flanged bore 25a projecting into the intake end of the shaft. An insulating layer 29 is provided between the sleeve 7 and the stator 9. Alternatively the space between the sleeve 7 and the motor casing may be filled with insulating resin. To prevent electrolytic corrosion of the unit a consumable electrode (31) of, for example, magnesium may be secured to the sleeve 7 or end-plate 3, Fig. 5 (not shown). In another embodiment Fig.10 (not shown) foreign material in the liquid is prevented from entering the rotor chamber by filters (39, 39<SP>1</SP>) located adjacent the bearing blocks. Alternatively, Fig.6 (not shown) foreign material is excluded from the rotor chamber by a disc (32) secured to the shaft 13 adjacent the bearing blocks 12 a hole (33) being provided in the shaft between the disc and the impeller to allow liquid circulation in the pump chamber and prevent any foreign material being trapped therein. A filter may be connected to the inlet opening in the casing 1 and the pump chamber may have a radial outlet in addition to the axial are shown. Fig. 8 shows a further modification in which the passages in the bearing blocks are omitted and sealing discs 35, 36 are provided between the blocks and shaft 13, the rotor chamber in this case being filled with lubricating liquid for the bearings. Resilient sealing rings may be provided at the ends of the rotor, Fig. 9 (not shown). In addition to the axial discharge port 2a, a radial discharge port (34), Fig. 7 (not shown) may be provided.