GB792354A - An improved valve for automatically controlling the water level in troughs and the like - Google Patents

Abstract

792,354. Fluid-pressure servomotor-control systems. WYLIE, J. Jan. 20, 1956, No. 2038/56. Class 135. The valve is secured in a vertical position to the edge of a water trough and water from the supply flows into a pipe 4 from which it exhausts into the trough via a filter 8, an orifice 9, an inlet chamber 5, a passage 23a, an outlet chamber 27 and an outlet 24a. As the trough fills, the water first covers a hole 25b in the bottom of a depending pipe 25a and then rises up the inside and outside of the latter causing increasing compression of the air trapped in the pipe 25a; as the water approaches the desired level 33 the air pressure is sufficient to lift a secondary diaphragm 26 so that a rubber or like valve closure 31 bears against a seat 23b at the extremity of the passage 23a and resists flow into the outlet chamber 27, whereupon the resulting pressure rise in the inlet chamber 5 elevates a spring-loaded main diaphragm 10 and partially seats a rubber or like main valve closure 21 in the orifice 9. When the water reaches the level 33 the secondary diaphragm 26 causes the closure 31 to completely shut-off the passage 23a so that the pressure in the inlet chamber 5 acts on the diaphragm 10 and forces the main closure 21 completely into the orifice 9 to prevent any further flow through the apparatus. Removable plugs 32 in the pipe 25a are provided to compensate for lower supply pressures whilst a pipe of increased length is used if the supply pressure is very high.