Stcoch Yoke type pneumatic actuator is a kind of angular stroke piston actuator, which is suitable for switching off or metering control of 90 ° angle valves (such as ball valve, butterfly valve and plug valve).
Stcoch Yoke type pneumatic actuator, It usually refers to the structure of “single cylinder double piston variable torque Stcoch Yoke type” “Pneumatic actuator. Today’s fluid control equipment should be economical and have the characteristics of high performance, long life, safety and reliability, energy conservation and environmental protection. It can significantly reduce the total cost of ownership of the plant with less downtime and lower energy consumption. Stcoch Yoke type pneumatic actuator is produced according to the high requirements of working conditions and the development needs of the industry. In the future, Stcoch Yoke type will be the dominant era.

working principle
The compressed air enters the cylinder and pushes the Stcoch Yoke piston to move. Through the Stcoch Yoke, the linear motion of the piston is transformed into the rotary motion of the disc, and the disc drives the output shaft to rotate, so as to realize the control of the valve.

Structural features
When the Stcoch Yoke type pneumatic actuator works, during the movement of the piston, there is rolling friction between the Stcoch Yoke plate and the self-lubricating rotating pin, and there is no wear between the Stcoch Yoke plate and the rotating pin. The transmission is that the friction and assistance of the two are small.

Torque characteristics
1. Small volume, large torque
The disc of the Stcoch Yoke type pneumatic actuator is connected with the Stcoch Yoke, and the rotating pin is connected with the disc through the pin. The size of the disc can approach the cylinder diameter, and the pin connected between the Stcoch Yoke and the disc is close to the edge of the disc, so it can obtain a larger output torque with a smaller size.
When the air supply pressure f is the same and the piston diameter is the same, the Stcoch Yoke actuator can produce a longer force arm l than the rack and pinion actuator, according to the torque M = F × 50. It can be seen that the Stcoch Yoke type can produce greater torque than the rack and pinion actuator under the condition of the same volume.
2. The output torque changes with the angle change, which meets the torque change characteristics when the valve is opened and closed
The disc structure of the Stcoch Yoke pneumatic actuator is unique, and its connection with the pin has a special curve design. During operation, the output torque can change with the change of angle, and reach the maximum at the opening and closing points. The characteristics of output torque are consistent with the characteristics of the maximum torque required for the opening and closing of butterfly valve and ball valve. It is an actuator that can really give full play to the performance of the valve and prolong the average service life of the valve.

Product classification
According to different types of functions, it can be divided into single acting Stcoch Yoke pneumatic actuator and double acting Stcoch Yoke pneumatic actuator. The switching action of the actuator is driven by the air source, which is a double acting Stcoch Yoke pneumatic actuator; Only the opening action is driven by the air source, and the closing action as spring return is the single acting Stcoch Yoke pneumatic actuator.
According to different structures, it can be divided into single cylinder piston type and double cylinder piston type.
According to different main materials, it can be divided into aluminum alloy type, stainless steel type, carbon steel type, etc.

Product introduction
1. Standard Stcoch Yoke type pneumatic actuator
Torque: 8nm ~ 8000nm (double acting) 15nm ~ 4000nm (single acting)
Angle: 90 ° (0 ~ 10 ° or 80 ~ 90 ° adjustable)
Air source: 5.6bar under normal conditions, 8.4bar at most
Temperature: 0 ℃ to + 80 ℃ (optional: low temperature type – 40 ℃, high temperature type 150 ℃)
2. Adjustable Stcoch Yoke type pneumatic actuator
The rotation stroke of the actuator is divided into two sections, and the valve is closed or opened in sections, which can make the same ball valve or butterfly valve realize two different opening values, so as to have different flow values. It can replace the flowmeter for accurate measurement. It is used for quantitative filling ball valve, butterfly valve or segmented filling ball valve and butterfly valve in food and beverage, medicine, paint, cosmetics, petrochemical and other industries.
Torque: 30nm ~ 480nm
Adjustment angle: 0 ° ~ 90 °
Air source: 5.6bar under normal conditions, 8.4bar at most
Temperature: 0 ℃ to + 80 ℃
3. Integrated handwheel pneumatic actuator
The emergency operation handwheel mechanism is cleverly integrated into the actuator to save installation space. Through the movement of the screw, it acts on the actuator piston to achieve the effect of manual control in case of emergency.
Torque: 60NM ~ 960nm (double acting) 60NM ~ 480nm (single acting)
Angle: 90 ° (0 ~ 10 ° or 80 ~ 90 ° adjustable)
4. Steel Stcoch Yoke pneumatic actuator
There is a growing market demand for steel actuators (rather than aluminum actuators), especially in the oil and gas field, where aluminum actuators are not suitable for many occasions.
Steel Stcoch Yoke pneumatic actuators can be divided into stainless steel pneumatic actuators and carbon steel pneumatic actuators. The casting cost of stainless steel actuator (especially small size) has a certain competitive advantage compared with carbon steel actuator, and there is no need for surface treatment.
5. High torque Stcoch Yoke pneumatic actuator
Rack and pinion actuators are often not cost-effective when the torque requirement is higher than 7000nm. For this reason, when selecting pneumatic actuator, it is generally recommended to select high-power Stcoch Yoke pneumatic actuator, which can provide higher torque output.

The inclined steel Stcoch Yoke mechanism has very high starting torque and low operating torque, which is suitable for the control of butterfly valve; The symmetrical steel shift Stcoch Yoke mechanism has a more balanced torque curve, which is mainly suitable for the control of ball valve and plug valve.