The valve electric device is an indispensable device to realize valve program control, automatic control and remote control. Its movement process can be controlled by stroke, torque or axial thrust. Since the working characteristics and utilization 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 can prevent overloading (the working torque is higher than the control Torque) is very important. Generally, the correct selection of valve electric devices is based on the following:
Operating torque: The operating torque is the most important parameter for selecting the valve electric device. The output torque of the electric device should be 1.2 to 1.5 times the maximum valve operating torque.
Operating thrust: There are two main structures of the valve electric device: one is not equipped with a thrust plate, and the torque is directly output; the other is with a thrust plate, and the output torque is converted into output thrust through the stem nut in the thrust plate.
Number of rotations of the output shaft: The number of rotations of the output shaft of the valve electric device is related to the nominal diameter of the valve, the pitch of the stem, and the number of thread heads. It should be calculated according to M=H/ZS (M is the total rotation that the electric device should meet The number of turns, H is the opening height of the valve, S is the thread pitch of the valve stem driving thread, and Z is the number of stem thread heads).
Stem diameter: For multi-turn open-stem valves, if the maximum stem diameter allowed by the electric device cannot pass through the stem of the matched valve, it cannot be assembled into an electric valve. Therefore, the inner diameter of the hollow output shaft of the electric device must be larger than the outer diameter of the stem of the rising stem valve. For part-turn valves and dark-stem valves in multi-turn valves, although the passage of the stem diameter does not need to be considered, the stem diameter and the size of the keyway should be fully considered when selecting and matching, so that it can work normally after assembly.
Different valve devices are used in different types, with different price and quality, and different fields of use. The valve devices selected by many companies will be more or less overloaded after they are used. In fact, you must explain where to use them before purchasing. Do not buy blindly and choose the inappropriate ones.
