The correct choice of valve electric device should be based on:
1. Operating torque: 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 torque of the valve.
2. Operational thrust: The main structure of the valve electric device has two kinds. One is that no thrust plate is disposed, and the direct torque is output at this time; the other is configured with a thrust plate. At this time, the output torque passes through the stem nut in the thrust plate. Convert to output thrust.
3. Rotation number of output shaft: The number of revolutions 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 is calculated according to M=H/ZS (where: M is the electrical device should satisfy The total number of turns; H is the opening height of the valve, mm; S is the thread pitch of the stem transmission thread, mm; Z is the number of stem threads.)
4. Stem diameter: For multi-turn type stem valves, electric valves cannot be assembled if the maximum stem diameter allowed by the motorized device cannot pass through the stem of the valve with which it is fitted. 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 stem valve. For the partial rotary valve and the multi-rotary valve, although the stem diameter does not have to be taken into account, the diameter of the stem and the size of the key groove should be fully taken into account in the selection so that the assembly can work normally.
5. Output speed: The valve's opening and closing speed is quick, easy to produce water hammer phenomenon. Therefore, appropriate opening and closing speeds should be selected according to different conditions of use.
6. Installation and connection methods: The installation methods of the electric device include vertical installation, horizontal installation, and floor installation; the connection mode is: thrust plate; the valve stem passes (many-rod multi-turn valve); the dark bar multi-rotation; no thrust plate; the valve stem is not Through; the use of a part of the rotary electric device is very wide, is an indispensable device to achieve valve program control, automatic control and remote control, which is mainly used in closed-circuit valves. However, the special requirements of valve actuators cannot be ignored—it must be possible to limit the torque or axial force. Usually the valve electric device uses a torque limiting coupling.