GB1374524A - Piston pumps - Google Patents

Abstract

1374524 Reciprocating pumps ROBERT BOSCH GmbH 21 Jan 1972 [27 Jan 1971] 2994/72 Heading F1A A reciprocating pump, e.g. a radial piston pump, in which fluid from duct 23 is drawn, via a recess 15 and orifices 17-17"' in a stationary flow control member 12 into the bores 5 of a rotating cylinder block 6 to be discharged via orfices 18-18''' past non-return ball valves 20-20''' and a recess 16 also all in member 12, to a discharge duct 26 as the spring-loaded pistons 7 which contact a ball race 4 reciprocate on rotation of the block 6, is provided in the supply duct 23 with a spring-loaded slide valve 24 responsive to the pump delivery pressure. When the pressure in duct 26 becomes too great, valve 29 opens to admit fluid from duct 26 via duct 28 to chamber 25" to move valve 24 to the right against spring 30 to throttle the flow through duct 23. After the consequent fall in pressure in duct 26 valve 29 closes, and spring 30 restores valve 24 to its original position, the fluid displaced from chamber 25" passing through bore 33, chamber 25' and duct 23' to the supply duct. If the pressure in duct 26 and so chamber 25" is very large valve 24 moves so far to the right that chamber 25" directly communicates with supply duct 23 through groove 32 to act as a relief valve. In modifications (not shown) the pump may comprise an axial or a radial piston pump in which the flow control member comprises a planar or part-spherical valve plate provided on its outlet side with a plurality of orifices each containing a non-return valve and leading to a common recess and discharge duct.