GB801951A - A fluid-pressure control system for remotely controlling fluid control valves - Google Patents

Abstract

801,951. Fluid-pressure servomotor-control systems. JAROCO ENGINEERING CO. Sept. 24, 1956 [May 23, 1956], No. 29154/56. Class 135. A fluid-pressure servomotor-control system for remotely controlling and indicating the operational position of a valve, e.g. a valve in the loading and discharge line in the hold of an oil-tanker, comprises a piston 32 slidable in a cylinder 34 and operatively connected to a valve 20 controlling a line 14 in the ship's hold. The upper end of the cylinder 34 is connected by a line 36 to a chamber 38 mounted on the upper deck and surmounted by a pressure gauge 40 whilst the lower end is connected by a line 62 to a manually-operable piston control valve 42 controlling a port 52 connected to an accumulator 92 supplied with pressure liquid by a motor-driven pump 100 and a port 54 connected to a reservoir 106. The space above the piston 32 and the chamber 38 are filled with gas at a predetermined pressure, e.g. nitrogen, as also is the accumulator space 96. Hydraulic pressure in the cylinder 34 is transmitted through the line 62 and a branch line 64 to act on the piston 46 of the valve 42 in opposition to a spring 84 acted upon by a camoperated plunger 88. The cam 70 mounted on a lever 66 movable over a graduated quadrant 78 adjusts the loading of the spring 84 and hence the hydraulic pressure in the cylinder 34 to position the piston 32 and the valve 20 in accordance with the position of the lever; the gas in the cylinder 34 and the chamber 38 being compressed to a greater or lesser extent and its pressure recorded on the gauge 40 to indicate the amount of opening of the valve 20. The accumulator 92 may be connected to any number of similar control valves 42 each operating through a piston 32 a valve 20. The chambers 38 with their gauges 40 are conveniently grouped together at a central location to permit of supervision of the loading and discharge operations.