GB724652A - Aircraft fuel systems and booster pumps therefor - Google Patents

Abstract

724,652. Centrifugal pumps. NASH ENGINEERING CO. Jan. 14, 1953 [Feb. 8, 1952], No. 1101/53. Class 110(1). [Also in Group XXIX] A fuel booster pump comprises a centrifugal impeller having two separate sets of blades separated by a central partition, a pump body divided into two pumping chambers by the partition, vacuum pumping means having separate connections for drawing off vapour and gas from the two chambers, an intake connection adjacent to and connected to the entry eye of one chamber, and an intake extension in communication with the entry eye of the other chamber and extending away from the pump body with its intake end at a substantial distance from the body, the pump being adapted to operate with one or both intakes submerged. The pump 12 is mounted within an opening 11 in the bottom wall 10 of an aircraft fuel tank. Fuel flows through a strainer 25 and inlet chamber 26 to blades 44 carried on one side of an impeller disc 43. Fuel flows to the blades 45 on the other side of the disc 43 by way of a strainer 27 and an inlet stack 15. The pumped fuel is discharged by way of a volute 24 to a discharge connection 18. Vapour and gas in the fuel are collected in annular grooves 34, 35 and conveyed by ducts 36, 37 and 40 respectively to separate lobes 39, 42 respectively of a liquid-ring vacuum pump 30, from which they are discharged through a pipe 53. The impeller 19, which is similar to that described in Specification 654,871, has an entrance area which is large compared with the discharge, so that each side of the impeller can handle 1¢ to 2 times the total discharge capacity. Consequently, a ring of liquid is built up around the impeller periphery and extending into the blade passages. If one inlet becomes uncovered because of a fall in the level of fuel in the tank or as the result of an acceleration or a change of attitude of the aircraft, so that one side of the impeller 19 becomes exposed to air, the ring of liquid seals that side from the other side of the impeller and allows the latter side to remain in operation. The driving motor 14, which may be an electric motor or an air turbine, may be located at the opposite side of the impeller to that shown, and may be mounted outside the tank. Specifications 648,546 and 654,853 also are referred to.