Pneumatic Actuator

Air actuated ANSI 150 lb. stainless flanged ball valve for on-off control of water, air, oil and other compatible media.  Spring return actuators require a pneumatic pilot signal to change the valve position, springs will return the valve to the normal failsafe position.

Double acting actuators use air pressure to open the valve and air pressure to close the valve.  Advantages of air actuated ball valves over other type valves may include:  Higher flow rates, higher pressures, higher temperatures, wider media compatibility, straight through flow path, reduced water hammer, and use in hazardous environments.


Pneumatic Actuator


Spring return pneumatic actuator directly mounted on a 2-way stainless steel sanitary ball valve
– Specification of the SR pneumatic actuator refers to spring return
– Features of 2-way, 3 piece stainless steel sanitary full port ball valve:
  * Full port sizes
  * ISO 5211 mounting pad
  * Working pressure 1000 psi WOG (1/2″ to 3″) 800 psi WOG (2-1/2″ to 3″)
  * Temperature range -60 to 450 degree Fahrenheit
  * Anti-Static

Principle of operation for Pneumatic Actuator

A Pneumatic actuator mainly consists of a piston or a diaphragm which develops the motive power.  moreover, it keeps the air in the upper portion of the cylinder, allowing air pressure to force the diaphragm or piston to move the valve stem or rotate the valve control element.

Also the valves require little pressure to operate and usually double or triple the input force.  The larger the size of the piston, the larger the output pressure can be.  Having a larger piston can also be good if air supply is low, allowing the same forces with less input.

In addition, these pressures are large enough to crush objects in the pipe.  On 100 kPa input, you could lift a small car (upwards of 1,000 lbs.) easily, and this is only a basic, small pneumatic valve. However, the resulting forces required of the stem would be too great and cause the valve stem to fail.



Valve Stem and Valve Plus for the Pneumatic Actuator


This pressure is transferred to the valve stem, which is connected to either the valve plug (see plug valve), butterfly valve etc.  Also, larger forces are required in high pressure or high flow pipelines to allow the valve to overcome these forces, and allow it to move the valves moving parts to control the material flowing inside.

Finally, the valves input is the “control signal.” This can come from a variety of measuring devices, and each different pressure is a different set point for a valve.  Finally, a typical standard signal is 20–100 kPa.  For example, a valve could be controlling the pressure in a vessel.  It  has a constant out-flow, and a varied in-flow (varied by the actuator and valve).


Transmitters for Pneumatic Actuator


Furthermore, A pressure transmitter will monitor the pressure in the vessel and transmit a signal from 20–100 kPa.  At 20 kPa means there is no pressure.  At 100 kPa means there is full range pressure (can be varied by the transmitters calibration points).

Also, as the pressure rises in the vessel, the output of the transmitter rises.   It is this increase in pressure that is sent to the valve.  In turn, this is what causes the valve to stroke downward, and start closing the valve. 

In addition, this will also decrease flow into the vessel, reducing the pressure in the vessel.  Finally, It is because the excess pressure is evacuated through the out flow.  Also, this is called a direct acting process.


In Conclusion, if this type of Pneumatic Actuator does not meet your requirements, pls contact SRS or see our other products below

Control Valves


Additional information

Weight 5 lbs
Dimensions 12 × 12 × 12 in
Connection end

Flanged, Threaded, Triclamp


1/4, 3/8, 1/2, 3/4, 1, 1-1/2, 2, 3, 4

Materials of Construction

Carbon Steel, Stainless Steel


1, 2, 3








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