Scotch Yoke Pneumatic Actuator: An industrial tool for precise control and efficient driving

Scotch Yoke Pneumatic Actuator, also known as Scotch Yoke Pneumatic Actuator in Chinese, is an angular stroke piston pneumatic actuator widely used in industrial automation control systems. It is driven by compressed air to realize the switch-off or metering control of 90° angle valves (such as ball valves, butterfly valves, and plug valves), providing strong support for the efficient operation of modern industry.

The working principle of the Scotch Yoke Pneumatic Actuator is not complicated, but the design is very sophisticated. When compressed air enters the cylinder, it pushes the piston to move linearly. The piston cleverly converts the linear motion into the rotational motion of the fork through the design of the piston pin and the U-shaped groove of the fork. The rotation of the fork then drives the rotation of the output shaft, thereby achieving precise control of the valve. This design not only improves the reliability and durability of the actuator, but also makes the Scotch Yoke Pneumatic Actuator perform well in large-caliber and high-torque situations.

Depending on the type of action, Scotch Yoke Pneumatic Actuators can be divided into single-acting and double-acting. The switching action of the double-acting scotch yoke pneumatic actuator is driven by the air source, while the single-acting scotch yoke pneumatic actuator only has the opening action driven by the air source, and the closing action is reset by the spring. This design enables the single-acting actuator to automatically reset in the event of power failure or gas failure, which improves the safety of the system.

The structure of the scotch yoke pneumatic actuator is also diverse, including single-cylinder piston type and double-cylinder piston type. Actuators of different structures are suitable for different working conditions, and users can choose according to actual conditions. There are also many choices for the main materials of the scotch yoke pneumatic actuator, such as aluminum alloy type, stainless steel type, carbon steel type, etc., to meet the requirements of corrosion resistance, wear resistance, and rust resistance in different environments.

The advantage of the scotch yoke pneumatic actuator is that it can provide high torque output, especially for occasions with high torque requirements. When the torque requirement is higher than 7000Nm, the rack and pinion actuator is often not cost-effective, while the scotch yoke pneumatic actuator can meet the demand with its higher torque output and more economical cost. The scotch yoke pneumatic actuator also has the advantages of large opening and closing torque, long service life, small size, light weight, easy installation, low gas consumption, energy saving and environmental protection, and fast working speed.

It is particularly worth mentioning that the scotch yoke mechanism of the scotch yoke pneumatic actuator is uniquely designed and is divided into two types: inclined and symmetrical. The inclined steel scotch yoke mechanism has a very high starting torque and a low operating torque, which is very suitable for the control of butterfly valves; while the symmetrical steel scotch yoke mechanism has a more balanced torque curve, which is mainly suitable for the control of ball valves and plug valves. This design not only improves the control accuracy of the actuator, but also makes the scotch yoke pneumatic actuator perform well under complex working conditions.