Scotch Yoke Type Pneumatic Actuator

Scotch Yoke Type Pneumatic Actuator ，isthe abbreviation for the "diaphragm single cylinder double piston fork type variable torque" pneumatic actuator. The Scotch Yoke Type Pneumatic Actuator，was independently developed and manufactured by OMAL Fluid Control Valve Company in Italy in 1981. It broke the monopoly of rack and pinion pneumatic actuators in the world at that time and quickly gained an important position in the actuator field with its characteristics of "small size, light weight, and high torque". The so-called Scotch Yoke Type Pneumatic Actuator adopts a "single cylinder, double piston, fork type variable torque" transmission structure, which allows the output torque to change with the angle. In the open or closed position of the valve, the torque value is the highest, consistent with the law of the valve, and there is no torque waste. Therefore, the required cylinder diameter can be smaller; Secondly, the height of the fork and fork arm of the fork type pneumatic actuator coincide, greatly saving space.

Scotch Yoke Type Pneumatic Actuator  is a stroke piston type actuator suitable for shut-off or metering control of 90 ° angle valves (such as ball valves, butterfly valves, and plug valves). Scotch Yoke Type Pneumatic Actuator，usually refers to the structure of a "single cylinder double piston variable torque fork type" pneumatic actuator.

Working principle of Scotch Yoke Type Pneumatic Actuator:

Compressed air enters the cylinder and pushes the piston in a straight line motion. The piston utilizes the U-shaped groove design of the piston pin and shift fork to convert the linear motion of the piston into the rotation of the shift fork. The rotation of the fork drives the output shaft to rotate, thereby achieving control of the valve.

Product Classification of Scotch Yoke Type Pneumatic Actuator:

According to the different types of actions, it can be divided into single acting Scotch Yoke Type Pneumatic Actuator and double acting Scotch Yoke Type Pneumatic Actuator. The opening and closing actions of the actuator are all driven by an air source, which is a double acting Scotch Yoke Type Pneumatic Actuator；The only opening action is driven by the air source, and the closing action is a spring reset which is a single acting Scotch Yoke Type Pneumatic Actuator.

According to different structures, Scotch Yoke type pneumatic actuators can be divided into single cylinder piston type and double cylinder piston type.

According to the different main materials, Scotch Yoke type pneumatic actuators can be divided into aluminum alloy type, stainless steel type, carbon steel type, etc.

When the torque requirement is higher than 7000Nm, rack and pinion actuators are usually not cost-effective. Therefore, when choosing a Scotch Yoke type pneumatic actuator, it is generally recommended to choose a high-power fork type pneumatic actuator, which can provide higher torque output.

The symmetrical and inclined steel fork mechanisms of high-power Scotch Yoke type pneumatic actuators allow for two torque output characteristics. The inclined steel fork mechanism has high starting torque and low operating torque, making it suitable for controlling butterfly valves; The symmetrical steel fork mechanism has a more balanced torque curve and is mainly suitable for valve control of ball valves and cocks.

AD Series（Double action）

AS Series（Single Action）