GB757608A - Improved fluid pump, particularly for fire fighting vehicles - Google Patents

Abstract

757,608. Centrifugal and axial-flow pumps. HATHAWAY, Ltd., L. Oct. 21, 1954 [Oct. 21, 1953], No. 29023/53. Class 110(1) In a two-stage pump, the high-pressure stage is adapted to be optionally driven, through gearing, from the driving shaft of the lowpressure stage. The shaft 15 of the low-pressure pump im. peller 14 of a fire-fighting pump is driven through a shaft extension 15a and a coupling flange 38 by, say, a power take-off of a motor vehicle. The high-pressure pump impeller 26 is driven from the shaft extension 15a through step-up gearing 41, 47, 50, 51 and a clutch comprising a driven member 4C connected to gear wheel 41 and freely rotatable on shaft extension 15a and a driving member 39 which is splined to the shaft extension 15a. Member 39 is moved axially into engagement with member 40 against the pressure of coil springs 45 by means of oil or other fluid under pressure, supplied to chamber 44 by way of a duct 43. The oil is supplied by a pump (not shown), driven by a gear wheel 46, the supply being controlled, for the purpose of actuating the clutch, by a manually actuated valve (not shown). The pump has a main inlet 12 connectible to an external supply of water and closable by a cap and a branch inlet 13 which is connected by way of a closable valve to a storage tank on the vehicle. Water can be taken off at low pressure from the outlet chamber 21 of the low-pressure stage and at high pressure from the outlet 34 of the high-pressure stage. The two stages are connected in series through a duct 23. When high-pressure water is not required, the clutch can be disengaged. The pump may be of the axial-flow type instead of centrifugal. The Provisional Specification refers to Specification 730,459.