GB628279A - Turbine driven fluid circulating unit - Google Patents

Abstract

628,279. Centrifugal and axial-flow fans, etc.; turbines. GARRETT CORPORATION. Jan. 29, 1947, No. 2754. Convention date, July 26, 1946. [Classes 110(i) and 110(iii)] 'Direct-drive axial-flow fans; casings; centrifugal fans in parallel; combinations of fans; radial-flow turbines; nozzles; bearings; lubrication. In a turbine-fan unit the turbine and fan are arranged at opposite ends of a housing containing an oil reservoir and a tubular support for the bearings of the shaft, and means are provided for conducting oil to the shaft and for circulating through the bearings oil mist formed by the shaft; the latter means comprise small centrifugal fans on the shaft at the ends of the bearing support. Passages are formed through the bearing support to equalise the pressure on the outer sides of the two bearings. In the form shown an inward-flow turbine rotor 12 and an axial-flow fan 13 are used, and the housing comprises a casing 10 having an outer wall, an inner wall 47, and an end wall 51, forming an inlet chamber 50 for the axial-flow fan rotor 13, and a lubricating chamber 49; the walls 47 and 51 are connected by upper and lower members 35, and are formed with rings supporting the ends of a bearing support 21. The casing carries an extension 82 forming an outlet passage for the fan 13 and having an inner fairing 85<1> covering the hub and securing means of the fan rotor. The bearing support 21 is of tubular form, enclosing a space round the enlarged central portion 14 of the shaft and receiving ballbearings at its ends, the left-hand bearing being inserted against a compression spring. The fan inlet chamber has its entrance opening at the bottom, and is divided into two halves by a vertical partition 76, 77; it has a number of vanes adjacent to the fan rotor. The turbine casing 60 provides an inlet chamber 62 (with lateral entry) and an axial outlet passage 65 and has an end wall 66 facing the blades of the rotor 12 and constituting one side of a nozzle ring, the other side of this ring being constituted by a plate 67 bearing the blades which form the nozzles; the plate 67 is seated on a gasket 59 on the end wall 51 of the casing 10 and located by a flange extending into a recess in the wall 51, and is secured by the pressure of the casing 60, which is also seated on the gasket 59 and fixed by screws to the casing 10. The chamber 49, of which the lower part forms an oil reservoir and has a lateral extension with filling and drain plugs, communicates with the interior of the bearing support 21 by radial passages 43 therein, and a doubled wick passes from the oil reservoir through two of these passages and rests against the shaft; oil passing on to the shaft is thrown off to produce a mist, which is circulated through the bearings by means of small centrifugal fans 25 at the ends thereof, being returned to the chamber 49 by way of longitudinal bores 42 in the wall of the bearing support 21 and lateral openings 45 into these bores. The ends of the bearing assembly are closed by plates 37, 38, surrounding the hubs of the turbine and fan rotors respectively, and leakage of oil past these plates is minimised by the pressure created outside the plate 38 by the fan rotor, which pressure is communicated to the centre of the plate 37 by way of bores 90, in the casing members 35, and 91. The construction of the turbine casing is claimed in Specification 628,313.