GB768240A - Improvements in or relating to liquid pumps in gas-turbine engines - Google Patents

Abstract

768,240. Centrifugal pumps. ROLLS ROYCE, Ltd. Nov. 15, 1954 [Dec. 21, 1953; Feb. 16, 1954], Nos. 35548/53 and 4586/54. Class 110 (1). [Also in Group XXXIV] A pump arranged to scavenge oil from a bearing of a gas turbine engine and to deliver it against a resistance comprises a vaneless impeller in the form of a circular disc, collar or radial flange, the impeller rotating within an encircling structure having a groove which receives the periphery of the impeller with a small clearance relative to the bottom of the groove, and at least one outlet passage extending from the bottom of the groove. A sleeve-like member 42 is interposed between a bearing 41 and the nut 43 which clamps the inner race of the bearing against a shoulder 40a on the vertical shaft 40 of an aircraft gas turbine engine of the type having a substantially vertical axis. An upper labyrinth seal 47 and the outer race of the bearing are attached to stationary structure 45 by studs 46. A lower labyrinth seal 50 is carried by a bearing housing 48. The member 42 has a radial flange 51, the periphery of which has a small clearance from the wall of the housing 48, and a cylindrical extension 52 of the flange depends into an annular recess 53. The member 42 acts as a centrifugal oil thrower to assist in scavenging the oil from the bearing 41, the oil draining on to the upper surface of the flange 51 being flung outwards on to the wall of the housing 48, which forms the bottom surface of a radial groove, and discharged through one or more passages 54. The latter, which are preferably tangentially disposed, lead to one or more pipes 55 which may lead to a scavenge pump 56. If, however, the oil flow is insufficient to fill the clearance between the flanges 51, 52 and the wall of the housing 48, the oil tends to fill the recess 53. Before it can reach the level of a side wall 50a of the recess 53, the oil is rotated by the axial flange 52 and, as before, discharged through the passages 54. In a modification, applied to an aircraft gas turbine engine having a horizontal shaft, the axial flange is omitted from the oil thrower.