GB710095A - Improvements in mechanism for controlling the speed of a fluid-actuated prime mover, e.g. an air-driven turbine - Google Patents

Abstract

710,095. Air turbines. GARRET CORPORATION. March 5, 1951 [March 20, 1950], No. 5279/51. Class 110(3) [Also in Group XXIX] A speed governor for a turbine 10 driving an alternator 12 and fed with motive fluid e.g. compressed air, through a conduit 14, comprises a valve 22 in the conduit and actuated by a diaphragm 28 controlled by a pilot valve 37 movable by flyballs 41 driven by the turbine through gearing 19, 44. The chamber 26 beneath the diaphragm is connected to a pipe 33 at one end joined through a restrictor 34 to the conduit 14 and at the other end forming a seat 35 for the pilot valve which allows air to bleed from the pipe 33 when the turbine is at the desired speed. Thus should the turbine speed exceed the desired value, the valve 37 will move to permit a larger bleed thus reducing the pressure in the chamber 26 and permitting a spring 30 to move the valve 22 in a closing direction to reduce the speed. Similarly a decrease in speed below the desired value causes the pilot valve to decrease the bleed, thus increasing the pressure in the chamber 26 to move the valve 22 towards open position. The pipe 33 has another outlet 36 forming a seat for a solenoid-actuated valve 38 which may be opened by closing a switch 47 to cause complete closure of the valve 22. In a modification. the valve 38 is movable manually or by an electric motor to permit a constant bleed from the pipe 33 thereby setting the desired speed of the turbine. An electrically-operated stop-valve 48 may be provided upstream of the valve 22. In another arrangement. the valve 37 is arranged to control the supply of air to the chamber 26.