Patent ID: 6032919
Filing Date: 2000-03-07
Classification: F16K,G05D,Y10T

Abstract:
A valve system for proportioning and controlling gas flow, said valve system comprising:(a) a source of pressurized air flow;(b) a flow control valve capable of pneumatic actuation between fully opened and closed positions corresponding permitting and preventing gas flow therethrough and to selected intermediate positions progressively increasing and decreasing between fully closed and opened positions to provide proportionately greater and lesser opening of said flow control valve and magnitude of the pressure and velocity of gas flow therethrough;(c) a first latching valve connected to said source of pressurized air flow, to said flow control valve and to a vent line and being switchable between an opened condition in which communication of pressurized air flow is only provided therethrough from said source of pressurized air flow to said flow control valve and a closed condition in which communication of pressurized air flow is only provided therethrough from said flow control valve to the vent line;(d) a second latching valve connected to the vent line from said first latching valve and to atmosphere and being switchable between an opened condition in which communication of pressurized air flow is only provided therethrough from the vent line to atmosphere and a closed condition wherein no communication of pressurized air flow is provided therethrough; and(e) a control mechanism operable to cause selective and separate switching of said first and second latching valves between said respective opened and closed conditions in a coordinated manner which causes pneumatic actuation of said flow control valve to any of said selected intermediate positions between said fully opened and closed positions.