Fluid handling – Ambient condition change responsive – For controlling soil irrigation
Patent
1987-01-21
1988-04-26
Chambers, A. Michael
Fluid handling
Ambient condition change responsive
For controlling soil irrigation
137 783, 137 785, 13762414, 47 485, 251 45, A01G 2500
Patent
active
047397896
DESCRIPTION:
BRIEF SUMMARY
This invention concerns a liquid flow control valve and particularly to a liquid flow control valve without the need for manual actuation.
Flow control valves are known in which servo control of the valve is possible using electrical or electronic means responding to a signal generated in response to a variable condition, for example a condition varied by the flow of 1iquid through the valve.
It is also known in a water cistern to control the level of water by a ball-cock having a ball floating on the water in the cistern and opening and closing the ball-cock according to variations in water level, the ball-cock controlling the flow of liquid into the cistern.
It is known from GB-845014 to provide a water responsive actuator for automatically inflatable lifesaving equipment in which a spring loaded plunger is held in a cocked position by a latch held in position by a thrust rod displaceable out of latching position by a stack of washer-like members disposed on the thrust rod and expansible on immersion to drive the rod out of a latching condition. This allows release of the plunger under spring force to operate a gas bottle to release gas.
It is known from U.S. Pat. No. 3,874,590 to provide a flow control valve operatively coupled to a moisture sensing element comprising a stack of moisture sensitive material operating a plunger against a spring loaded ball valve such that on drying of the material the plunger drives the ball against the spring and on moistening of the material the ball is driven by the spring. Under spring action the ball closes a by-pass when the material is wet, and the control valve is closed under supply water pressure. When the material is dry the ball is displaced to open the by-pass and a pressure signal from the water supply through the by-pass augments a spring pressure on a valve member to exceed supply pressure on an opposite side of the valve member to move the valve member to an open condition.
It is known from DE-A-2 513 600 to provide a flow control valve with a moisture sensitive control comprising a moisture expansible tubular member arranged on expansion to release a valve member which allows supply pressure to a closure diaphragm arranged to close a discharge outlet from the control valve. On drying of the expansible member it shrinks and drives the valve member to a closed condition whereby water pressure on an underside of the diaphragm opens the discharge of the control valve.
It is an object to provide an improved flow control valve embodying a moisture expansible control member.
A control valve according to the invention comprises a valve body having a liquid inlet leading to an inlet chamber and a liquid outlet leading from an outlet chamber, the inlet and outlet chambers communicating by a flow passageway closeable by a valve plate having one side facing the inlet chamber and the other arranged sealing to engage a valve seat to close the passageway, a thrust member extends from the valve plate away from the inlet chamber and being supported for opening and closing movement of the valve plate. Distal from the valve plate the thrust member is provided with a thrust plate disposed in a chamber adapted to receive fluid at pressure on a side of the thrust plate opposite the valve plate to drive the valve plate to an open condition. The inlet chamber communicates with by-pass means via a valved passage comprising a valve member moveable under liquid pressure in the inlet chamber to an open condition to allow flow of liquid through the bypass, and closeable from outside the inlet chamber, the by-pass leading to the liquid chamber to operate the thrust plate to open the valve plate, and means for closing the valve member comprising a control member including a thrust rod and a moisture expansible body arranged on ex pansion to drive the thrust rod to drive the valve member to a closed condition and on shrinking to release the valve member
In one arrangement the thrust plate and the liquid receiving chamber are separated by a resilient or flexible diaphragm sealing a liqu
REFERENCES:
patent: 2577337 (1951-12-01), Lancaster
patent: 2907347 (1959-10-01), Parks
patent: 2965117 (1960-12-01), Gallacher
patent: 3244372 (1966-04-01), Hanner
patent: 3465771 (1969-09-01), Tishler
patent: 3517684 (1970-06-01), Mitchell
patent: 3874590 (1975-04-01), Gibson
patent: 3972344 (1976-08-01), Chauvigne 137624.14
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