| 摘要 |
PROBLEM TO BE SOLVED: To provide an electropneumatic negative pressure control valve capable of preventing the residual pressure minutely left in an output port in the instruction of setting the control pressure of the output port to the atmospheric pressure, and suitably controlling an actuator or the like operated by control pressure. SOLUTION: A vacuum electropneumatic regulator 1 comprises a booster 20 controlled to be opened and closed by pilot pressures outputted from two solenoid valves. The booster 20 is of diaphragm type, and is selectively opened an air intake valve 26 and an air supply valve 27 according to the direction of motion of a valve bar 25 from the neutral position in response to the differential pressure between a pilot chamber and a feedback chamber located on both sides with the diaphragm inbetween. Since the valve element 31 of the air supply valve 27 is energized in the closing direction by a spring 32, the air supply valve 27 is closed before the control pressure becomes the atmospheric pressure when an input signal has a signal value 0% for setting the control pressure to the atmospheric pressure, but an output passage 37 is allowed to communicate with an atmospheric pressure passage 36 by a bleed port 44 formed in the valve element 31.
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