초록 ▼

A pneumatic-hydraulic proportional valve actuator system is provided having a relatively simple and adjustable means of achieving two stroking speeds by the hydraulic actuator, high speed in normal operation and low speed for small position adjustments and for the final part of any large position ad

A pneumatic-hydraulic proportional valve actuator system is provided having a relatively simple and adjustable means of achieving two stroking speeds by the hydraulic actuator, high speed in normal operation and low speed for small position adjustments and for the final part of any large position adjustments. This prevents overshoot and instability of the actuator.

대표청구항 ▼

A valve actuator system comprising: pressure source means including an accumulator charged to a predetermined pressure; piston means connectable to a valve control member for providing linear motion in response to pressure applied from said pressure source means; positioner means for establishing co

A valve actuator system comprising: pressure source means including an accumulator charged to a predetermined pressure; piston means connectable to a valve control member for providing linear motion in response to pressure applied from said pressure source means; positioner means for establishing control signals in response to differences between input signals to said positioner means indicative of desired valve positions and feedback signals to said positioner means indicative of actual valve positions; and means for moving said piston means at one of two speeds in response to the magnitude of the control signals from said positioner means including a restrictor and by-pass assembly connected between said accumulator and said piston means to provide two different fluid flow volumes depending on the magnitude of the control signals from said positioner means.