GB291764A - Improvements in and relating to regulators actuated by fluid pressure - Google Patents

Abstract

291,764. Canada Sugar Refining Co., Ltd., (Assignees of Wettstein, F. A.). June 8, 1927, [Convention date]. Regulation, automatic.-Relates to fluid pressure actuated regulators, primarily intended for automatic fluid pressure regulating valves, but applicable also for regulating other physical conditions, such as electrical voltage by means of a rheostat, these regulators being of the type provided with two fluid-pressure relays arranged in series, the first relay acting as the impulse receiver which, in the case of voltage regulation is operated by a solenoid, and the second relay as an amplifier which may react backwards on the first relay. Fig. 1 shows a pressure-reducing valve in which the pressure in the main beyond the valve 1 communicates through a conduit 4 with the first relay comprising a corrugated diaphragm 5 controlling a valve 11 controlling escape of the control fluid (e.g. oil) along conduits 8, 10 from the upper side of the differential piston 17 of the second relay which includes a pilot valve 18. The pressure fluid for actuation of the reducing valve (e.g. oil) is supplied by the conduit 20, through the pilot valve 18, and by the conduit 21 to the operating piston 25 of the main valve; a bye-pass from the conduit 21 leads to the differential chamber 22 from which fluid can escape through recesses 27 which are cut through the circumferential ribs 28 and are arranged alternately on opposite sides of the piston. A reduction of pressure in the outlet 3 causes movement of the diaphragm and throttling at the first relay valve 11, so that the pressure in the chamber 19 increases and forces down the piston 17 and opens the pilot valve 18, allowing an increased supply of the control fluid from the conduit 20 to pass to the piston 25 to open the main valve; the increased control pressure supply also passes to the differential chamber 22 and moves back the piston 17 and the valve 18 to throttle the passage thereby providing a fluid-pressure return-motion arrangement which prevents over-regulation or hunting. The pre-determined reduced pressure in the outlet 3 can be adjusted by operating the hand wheel 15, which alters the position of the sleeve 14 and the valve seating 13 in relation to the first-relay valve 11. The second relay can be operated manually in an emergency by the handle 31 and screwed spindle. The main valve is also operable manually by a bevel gearing and screw arrangement, as shown. A modification is described in which an electric motor running at constant speed operates a pump to supply the control pressure fluid.