The invention is in the valve by rotating the valve driving shaft using the first and second piston of the second cylinder in case of more than the valve opening and closing due to the addition of solenoid valve or a pneumatic supply to occur while operation of the valve means malfunction or power failure situations can maintain a stable operating state in the required position, to a valve actuator for opening and closing using air pressure is always made to open and close with a constant torque irrespective of the piston stroke changes.
The present invention relates to a valve actuator for opening and closing using air pressure to open and close by rotating the valve driving shaft formed by the first and second piston of the second cylinder, the first chamber air pressure upstream of the first cylinder, the second cylinder the second being provided indeed large pneumatic volume than the air pressure chamber the primary side, the primary side of the first pneumatic chamber is associated with a pneumatic supply and a first pneumatic tube, a first pneumatic tube is detected the electronic valve and the pressure of the pneumatic supply pneumatic detected and via the open side of the valve connected to the second pneumatic tube, and the second pneumatic pipe is respectively connected to the primary side of the secondary side and the second pneumatic chamber of the first pneumatic chamber, the second side of the second pneumatic chamber through the whole study it characterized the actuator for the valve opening and closing using air pressure comprising a structure that is in communication with the atmosphere.