You can select the actuator’s type according to the following parameters:
1. The max. torque and adjust torque for the valve,
The max. torque (if you need you can add the appropriate safety factor) is the rated torque of the actuator that you select. The adjust torque is the required torque when the valve is adjusted normally.
2. Moving speed of the valve
The rotate speed (rpm) of the actuator’s output shaft. If you know the stroke of the valve S (mm) , the stroke time T (s) and the lead of the valve-stem screw thread L (mm), then:Output shaft rotate speed=60S/TL (rpm)
According to the rated torque and output rotate speed, you can confirm the dimension No. of the actuator preliminarilywith <Actuator Date>.If the stroke time is longer (for example more than 10 minutes) ,you must figure the average torque of the valve during the actuator is running and check that if the average torque is more than one third torque of the selected actuator, if it is more , you must select the bigger type actuator. In the most conditions, you only need consider the rated torque.
3. Link mode of the flange
According to the detailed application situation and valve-stem dimension, you can select the appropriate link mode.
4. Parameters of the valve-stem
One important parameters of valve-stem is the external diameter. Each drive bush have a max diameter for valve-stem. You can confirm the actuator preliminarilyaccording to the step1 and 2 parameters, then according to the <Mechanical Interface Dimension >Table , check that if the external diameter is satisfied with the requirement of the valve-stem external diameter or not. If it is not satisfied, you can only select bigger actuator.
5. The required max. thrust of the valve
If this value is more than the rated torque that preliminarily selected actuator above (please check << dimension table of the type ----machine interface>>), you must select bigger actuator.
Notice: here the rated torque of the actuator is determined by not the max. thrust of the drive-nut but the machine intensity of the concerned parts. When you use the drive-nut on the primary valve, you may not need to consider this value.
Multi-Turn Electric Actuator
