GB1225108A - - Google Patents

Abstract

1,225,108. Hydrodynamic couplings. EATON YALE & TOWNE Inc. 22 Sept., 1969 [20 Sept., 1968], No. 46630/69. Headings F2C, F2D, F2E and F2L. A hydrodynamic coupling or brake for use with a gas turbine engine comprises axially spaced impeller and turbine elements 66, 46 having an annular discharge gap 73 therebetween which discharges into a low pressure zone. Hydrodynamic coupling.-In Fig. 6 bladed impeller and turbine elements 66c, 46c form a working circuit 67c therebetween and have an annular discharge gap 73c which discharges into a fixed casing 33c. The liquid in the casing 33c returns to a reservoir 76c through a port 44c having a greater cross-sectional area than the area of the annular discharge gap 73c. A pump 77c draws liquid from the reservoir 76c and delivers the liquid through a cooler 78c and control valve 79c to the working circuit 67c. The degree of coupling may be controlled by the valve 79c or may be controlled by a lever 126 which acts through a screw to move the turbine shaft axially and thus vary the size of the discharge gap 73c. Hydrodynamic brake.-In Fig. 2 (not shown) and Fig. 3 bladed rotor and stator elements 66A, 46A form a working circuit 67A, having a discharge gap 73A which in Fig. 2 discharges into a fixed casing (33) whilst in Fig. 3 the gap 73A discharges into an annular low pressure chamber 86 fast with the stator element 46A. In Fig. 3 liquid from the low pressure chamber 86 is returned to the working circuit through a port (96), a check valve 101, cooler 99 and control valve 79A. Leakage liquid is returned from the casing 33A to a reservoir 76A. The cross-sectional area of the discharge port 96 is greater than the area of the annular discharge gap 73A to ensure that the chamber 86 remains at a low pressure. The degree of braking is controlled by the valve 79A which regulates the supply of liquid to the working circuit.