Double acting actuator

The selection of double acting actuators takes DA series pneumatic actuators as an example. The output torque of the pinion actuator is the piston pressure (provided by the air source pressure) multiplied by the radius of the upper segment circle (moment arm), as shown in FIG. 4. The friction resistance is small and the efficiency is high. As shown in Figure 5, the output torque is linear for both clockwise and counterclockwise rotation. The recommended safety factor for double-acting actuators is 25 to 50% under normal operating conditions.

Single acting actuator

Taking SR series pneumatic actuator as an example in the application of spring return, the output torque is obtained in two different operation processes. According to the stroke position, each operation produces two different torque values. The output torque of the spring return actuator is obtained by multiplying the force (air pressure or spring force) by the moment arm: The output torque is obtained by the air pressure entering the cavity compression spring, which is called the "air stroke output torque". In this case, the air source pressure forces the piston to turn from 0 degrees to 90 degrees. Due to the spring compression reaction force, the torque gradually decreases from the starting point of the large value until the second condition: Cavity of the output torque is loss of gas spring back the force on the piston, known as the "spring travel output torque" in this case, because the spring elongation, output torque decline gradually from 90 degrees to 0 degrees such as described above, single-acting actuator is based on the two conditions to create a balanced torque on the basis of the design. See Figure 11. In each case, by varying the relationship between the number of springs on each side and the air source pressure (e.g., 2 springs on each side and 5.5 bar air source or vice versa), it is possible to obtain an unbalanced moment. Two conditions can be obtained in spring return applications: degout open or deGout closed. The recommended safety factor for spring return actuators is 25-50% under normal operating conditions.