GB880637A - Improvements relating to speed governors - Google Patents

Abstract

880,637. Centrifugal governors. FAIRCHILD ENGINE & AIRPLANE CORPORATION. June 9, 1959 [Sept. 17, 1958], No. 19738/59. Class 57. [Also in Group XXIX] A fluid-pressure governor operating, e.g. through an actuator 5 on the throttle 4 of a turbine 2, comprises a housing 10 which is rotated at a speed dependent on the turbine speed, the housing containing a movable valve member 16 which moves outwards centrifugally against the force exerted by a spring 19 which is connected between the valve member and a movable anchorage 20 within the housing, this anchorage being movable by fluid-pressure controlled means, such as a pressure-responsive diaphragm 21, within the housing in order to vary the setting of the governor, the pressure of the fluid transmitted to the diaphragm 21 being controlled by a regulator 32 outside the housing, the valve member controlling the flow of a second fluid through the housing which is arranged to operate the actuator 5. A port 44 in the hollow open-ended piston valve 16 controls the inlet of the second fluid to a control chamber beneath the piston, this fluid being supplied from a point upstream of the throttle 4 through a restriction 41. The lower edge of the piston controls a vent port 48, a control pressure from the chamber being led to the actuator 5 through a restriction 46. The control chamber is connected to the opposite side of the piston through a pair of restrictions 51, 52 and a volumetric passage 50 between them, the restriction 51 at the upper end of the piston being smaller than the restriction 52. Thus a space 15 above the piston functions as a dashpot chamber to prevent response to transient conditions arising, e.g. from torsional oscillation. Volumetric passage 50 between the restriction causes the pressure above the piston to lead or lag the pressure in the control chamber beneath it so that a temporary speed droop may be provided which has a stabilizing effect on the control system.