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Diaphragm and Piston Pneumatic Actuators

Diaphragm Pneumatic Actuator

Introduction and Operation


The actuator design is simple in concept. The operating principle and fewer components make this actuator long lasting and trouble free. It is rugged, easily adaptable, light weight, and easy to maintain.

Our Diaphragm Pneumatic Actuator can be used on land or offshore installations. This actuator delivers reliable fail safe performance. It is ideally suited for wellhead secondary master valves, wing valves, on flow lines, header valves, gathering lines and for casing relief valves. The maximum control pressure is 170psi (12 bar). A heavy duty spring insures complete valve stroke closure when gate valve pressure is at 0 psi.

Our Diaphragm Pneumatic Actuator can be prepared as a complete assembly with gate valve or as an actuated bonnet assembly.

The actuator is designed to operate any of the industry manufacturer’s gate valves. It is sized to provide optimal safety.  The utilization of materials, seals and coating application will provide years of service in the harshest environmental conditions



The Tiger Valve Pneumatic Diaphragm Actuator is operated by applying an adequate amount of compressed air, nitrogen or gas to the side pressure port on the diaphragm head. Pneumatic pressure acting on the internal diaphragm will force the actuator downward, overcoming opposing bonnet stem and gate friction forces.

Our Diaphragm Pneumatic Actuator will open reverse or direct acting gate valves. Reverse acting gates are labeled “Fail Closed” and direct acting gate valves are labeled “Fail Open”.  When actuator control pressure is removed the force/thrust upon the bonnet stem will close the gate to the “Fail Closed” position or “Fail Open” for direct acting gates.

When a reverse acting gate valve is closed with a pressure differential across the gate, the initial opening of the gate or “cracking” action will be quick and sudden. This is a normal action and does no damage to the gate valve. The function of the gate valve and actuator will not be impeded. The remainder of the stroke can be expected to be smooth and normal.

Upon loss of control supply pressure in the actuator, the closing motion should be smooth for the entire stroke. No hesitation or bumping should occur. As a rule of motion, the larger the exhaust port, the quicker the actuator will close.

 It is equipped with a large helical spring. This spring is required to overcome the basic seal friction and total weight of all moving components when no valve body pressure exists.