GB1389910A - Apparatus for controlling liquid pressure - Google Patents

Abstract

1389910 Liquid level control VIHORLAT NARODNY PODNIK 5 July 1972 [5 July 1971] 31394/72 Heading G1H [Also in Division G3] In an apparatus in which a liquid 4 subject to pressure in a vessel 6, closed to divert communication with atmosphere above an orifice 17, a control valve I is arranged to supply to or release gas from the container 6 from a pressurized gas source 14, in response to the relative magnitude of first and second control signals at 9 and 10, a sensor 8, such as a bellows/float, a probe Fig. 2 (not shown) or a float Fig. 3 (not shown) effects variation of the magnitude of the signal at 9 in order to maintain the liquid pressure at orifice 17 constant and the second control signal at 10 representative of the gas pressure at 2, applied to a pressure responsive drive counteracts pressure variation created by control 1 to the pressure 2 and a time clock 12, operative at predetermined intervals over-rides the control of the first signal at 9 from the sensor 3 to effect a programmed variation. The apparatus may be used for dispensing molten aluminium alloys into a pressure casting machine.