Pneumo Abex Corporation

Pneumo Corporation

Howard J Lambers

Michael D Herder

Robert D Vanderlaan

James N Tootle

Richard P Heintz

Eugene J Martin

Walter Fallows

Actuator control system includes two parallel connected orifices between a pair of fluid passages providing communication between an actuator and a flow control valve. Relief valves in series with the respective orifices block fluid flow through the orifices at low differential pressures between the fluid passages, thereby preserving the original high pressure gain of the control valve in a region about valve null. At higher differential pressures outside the valve null region, the relief valves open to permit restricted flow through the respective orifices to reduce the pressure gain of the control valve in a region outside the valve null region, which effectively reduces the stiffness of the control valve.

Fluid control valve with variable pressure gain

Flow control valve includes angled metering ports in the valve sleeve for directing the momentum of the fluid flow against the respective valve flow metering edges in a direction producing an opening reaction force on the valve upon initial valve opening in opposition to the usual axial flow forces tending to close the valve to reduce the flow force gain acting on the valve. Preferably, the angled metering ports are disposed at an angle of approximately 45.degree. or greater from a line perpendicular to the valve axis. Also, a single set of circumferentially spaced angled metering ports is desirably provided for each return or high pressure flow path for producing the desired opening reaction force on the valve.

Fluid control valves with angled metering ports

Multiple drive paths are provided between the valve plunger and force motor of a direct drive valve and force motor assembly whereby should one of the drive paths fail, the force motor can still be used to drive the valve plunger through another drive path. One of the drive paths consists of a drive shaft having one end drivingly connected to an eccentric on the motor output shaft and the other end connected to the end of the valve plunger remote from the motor output shaft. The drive shaft is desirably provided with an enlarged head portion having a flat annular surface on the axial inner end thereof in close proximity to a corresponding flat end face on the end of the valve plunger closest to the motor output shaft, whereby should the valve plunger break, the drive shaft will hold the valve plunger together and allow for degraded valve performance.

Redundant drive mechanisms for a direct drive valve and force motor

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Kalamazoo, MI, United States of America

Howard J Lambers