GB1180254A - Hydraulic Pumps - Google Patents

Abstract

1,180,254. Rotary positive displacement pumps. DANFOSS A.S. Nov. 13, 1967 [Nov. 29, 1966], No. 51524/67. Heading F1F. A rotary positive displacement hydraulic pump of the internally meshing n and n + 1 tooth type includes a circular vortex chamber II, Fig. 2, wherein any air entrained with the liquid e.g. oil, that is to be pumped by a pair of gear-wheels 16, 17 is separated from the liquid by centrifugal action. The vortex chamber is defined by a cap 7 and a plate 31, and contains three radially orientated uniformly disposed ducts 10 having inlet ports 6 at their outermost ends through which the air and liquid aforesaid enters the ducts from a chamber 2 within a cover 3 attached to a housing 33, the liquid being in the lowermost part of the chamber 2 so that mostly air enters the uppermost duct 10. A vortex is formed in the chamber II owing chiefly to the provision of a suction port 36, Fig. 3, and a duct 11 in the plate 31, said port being adjacent the perimeter of the chamber and said duct being substantially tangential to said perimeter. Liquid is drawn off through the port 36 into suction chambers 14, 20 adjacent the gear-wheels while a light mixture of air and liquid collects at the centre of the vortex. Periodically, any surplus air in the vortex is also drawn through the port 36. A filter 4 and a rubber diaphragm 5 are lodged in the chamber 2, which is charged with liquid through two ducts (1, Fig. 1, not shown), in the housing 33, the diaphragm serving to minimize pressure fluctuations. Separation of air and liquid in the vortex chamber is said to reduce noise.