The electric device of the electric valve is an indispensable device for realizing valve program control, automatic control and remote control, and the movement process can be controlled by the stroke, torque or axial thrust. Since the working characteristics and utilization rate of the valve electric device depend on the type of valve, the working specifications of the device and the position of the valve on the pipeline or equipment, the correct selection of the valve electric device prevents overloading (the working torque is higher than the control). Torque) is crucial.
In general, the basis for the correct selection of valve electric devices is as follows:
The operating torque is the most important parameter for selecting the electric device of the valve. The output torque of the electric device should be 1.2 to 1.5 times the maximum torque of the valve operation.
There are two types of main structures of the valve electric device: one is that the thrust plate is not arranged to directly output the torque; the other is to configure the thrust plate, and the output torque is converted into the output thrust through the stem nut in the thrust plate.
Output shaft rotation number:
The number of turns of the output shaft of the valve electric device is related to the nominal diameter of the valve, the pitch of the valve stem and the number of threads. It should be calculated according to M=H/ZS (M is the total number of revolutions that the electric device should meet, and H is the valve. Open height, S is the stem drive thread pitch, Z is the stem thread number).
For multi-turn type open-end valves, if the maximum stem diameter allowed by the electric device cannot pass through the valve stem of the valve, it cannot be assembled into an electric valve. Therefore, the inner diameter of the hollow shaft of the electric device must be larger than the outer diameter of the stem of the open rod valve. For the partial rotary valve and the dark rod valve in the multi-turn valve, although the problem of the diameter of the stem is not considered, the diameter of the stem and the size of the keyway should be fully considered in the selection, so that the assembly can work normally.