GB769763A - Improvements in or relating to gear pumps - Google Patents

Abstract

769,763. Gear pumps. AIR-EQUIPEMENT. May 18, 1955 [May 20, 1954; Feb. 8, 1955], No. 14331/55. Class 110 (2). The gears 101, 102, Fig. 2, of a gear pump are driven by a splined shaft 103, 104 and disposed between flexible gaskets 114, 115 which have orifices 119 formed opposite each of the cylindrical cavities 116, 117 in the covers 106, 107, gaskets 118 being provided as shown. When the pump is operating the cavities 116, 117 are fed with fluid at a pressure slightly higher than the average pressure in the adjacent space between two successive teeth. The inlet and outlet conduits are formed in the cover 106 and the oil leaking from the needle roller bearings 109, 110 is fed to a space 123 behind the gasket 115. In a modification, Fig. 4, sealing is effected by slidably mounted bearings 124 housing pistons 127 which abut the pump cover, each bearing being provided with a cavity 126 in communication with the fluid being pumped. In a second modification, Figs. 6, 7 and 11, channels 27, 27<SP>1</SP>, 27<SP>2</SP>, 27<SP>3</SP> are provided in the plate 22 so as to obtain back pressures which progressively fall from the discharge pressure in the case of channel 27 down to the suction pressure in the channel 273. Rubber gaskets 24, 241 are arranged in the covers 6, 7 respectively in contact with the plates 21, 22 and are perforated at 29, 29<SP>1</SP> . . . 30. The plates 21, 22 are perforated so that the cavities 29 ... 29<SP>8</SP> can be fed with pressure fluid, the cavity 30 being at the suction pressure. Plates such as 32 are pinned to the casing in order to limit the distortion of the gasket 24. In a third modification, Fig. 13, the bearings 39, 40 are fixed whilst the movable bearings 41, 42 are provided with openings 47, 48, whereby pressure fluid may be fed to the cavities 49, 50 of a gasket 51 which is held in position by a plate 54, 55. In a final modification, Fig. 17, applied to a pump of the internally-meshing gear type, the gasket 69 is provided with cavities which are fed with pressure fluid through holes 71 in a plate 66, the gasket being positioned by plates located in the cavities and pinned to the casing 67. If desired the locating plates for the gasket may be formed integral with the casing of the pump.