GB621612A - Improvements in gear-wheel pumps - Google Patents

Abstract

621,612. Gear pumps. PESCO PRODUCTS CO. Sept. 6, 1944, No. 17042. Convention date. Aug. 16, 1943. Addition to 572,967. [Class 110(ii)] A movable bushing forms a side wall bearing against each gear-wheel and has a piston portion against which fluid pressure is exerted. Passages 16 and 17, Fig. 3, act as inlet and outlet conduits respectively or vice-versa, depending on the direction of rotation. Fluid passes by way of one of two ball valves 88 to a chamber 72 and thence through the restricted annular space between a collar 68 and the stem of a metering valve 60 to a chamber 70. The fluid then passes by way of passages 78 to chambers 23, 56 where it exerts pressure on a flange 22 and a piston portion 27 so as to urge the bushing bearing 20 into sealing engagement with a gear-wheel 15. Excess pressure in the chambers 23, 56 is relieved by way of the valve 60, a passage 80 and a ball valve 82 to the inlet conduit 16 or 17. The valve 60 may be of such length that the adjusting screw 74, when screwed fully home, touches it and holds it against its seat 58. Fluid leaking between the gearwheel 15 and the bearing bushing 20 is relieved through a passage 90 into the passages 80. In an alternative construction, Fig. 6, separate spring-loaded pistons 112, 113, in fluid connection with the passages 17, 16 respectively, apply assymetrical loading between a bushing bearing 100 and the gear-wheel 15, the maximum loading pressure occurring approximately over the region of maximum fiuid pressure. A separate metering valve (not shown) for each piston 112, 113, similar to that shown in Fig. 3, is provided. Modified forms of these constructions, in which the metering valves: are omitted, are described.