Patent GB-839182-A (GB)
Title: Improvements in or relating to gas-turbine engines
Inventor: HAWORTH LIONEL
IPC: F01D21/02
Filed: 1956-05-25
Abstract: 839,182. Centrifugal governors. ROLLS-ROYCE Ltd. May 20, 1957 [May 25, 1956], No. 16331/56. Class 57. [Also in Group XXIX] A top speed governor arrangement of a gas-turbine engine comprises speed - responsive means accommodated within a hollow shaft portion of the turbine rotor structure so that in the event of failure of the drive shaft from the turbine to its load, the speed responsive means is still responsive to the rotational speed of the turbine rotor. The swash plate 24, Fig. 2, of the turbine fuel pump 14 is controlled by the spring- loaded servo - piston 25 the chamber 27 of which is connected by a bleed pipe 31 to a control mechanism, e.g. a barometric pressure control mechanism 32. A V-shaped conduit 44 connected to the bleed pipe 31 has an orifice 43 leading to the chamber 37 of a pressure - sensing mechanism 23 the housing 33 of which is divided into four chambers 34, 35, 36, 37 by three diaphragms 38, 39, 40, interconnected by a tie member 41 which carries the closure member 42 which controls the orifice 43. The diaphragm assembly 38, 39, 40 is loaded by oppositely acting springs 47 in the chambers 34, 37 which are interconnected by a duct 46. The chamber 37 is connected by a pipe 45 to the fuel pump inlet. The chambers 35, 36 are connected respectively to pipes 20, 49 in the turbine lubricating system which includes. Fig. 1, a pump 15, a filter 16, a reducing valve 18, a relief valve 19 and the tail part 12 of the turbine rotor disc 10. The pressure in the pipe 20 and chamber 35 is normally a constant amount above that in the pipe 49 and the chamber 36 so that the valve 42 is normally closed. Located within the tail part 12 of the rotor 10 is a speed-sensitive mechanism to be described later, which controls a pilot valve which interconnects the flow pipes 17, 20 and is normally closed. If the turbine rotor speed exceeds a selected value the speed-responsive means allows the pilot valve to be opened and the resulting flow in the pipe 20 causes a decrease of pressure in the chamber 35 so that the valve 42 is opened and the bleed from chamber 27 is increased causing the piston 25 to move the swash plate 24 to reduce the pump output. The speed-sensitive means, Fig. 3, which controls the control valve 61 of the servo-system comprises a pair of inclined flexible diaphragms 58 clamped to a housing 59 fitted within a easing 51 in the tail part 12 of the turbine rotor 10. The central boss members of the diaphragms are rigidly connected by arms 55 to a centrifugal mass 54. The diaphragm assembly 54, 55, 58 is loaded by a spring 62 so that an extension 60 of the arm 55 keeps the closure member 61 on its seat against the pressure of a spring 77. The pipe 49, Fig. 1, is connected to the pipe 17 which leads into the stator 13 of the tail portion 12, Fig. 3. Pressure oil flows from the pipe 17 through pipe 82, parts 85, sleeve 80 into the space containing the diaphragms from which the oil passes via a pipe 66 to bearings of the turbine plant. Oil pipe 20 is connected by a duct 91, the bore of a plug 88, a tube 92 to the tube 75 normally closed by the closure member 61 which is moved as described above to connect the two flow paths. Specification 839,181 is referred to.