Electric actuator selection for electric butterfly valves

Since the electric butterfly valve is composed of a butterfly valve and an electric device, how to correctly select the electric device after the electric butterfly valve is determined is an important factor related to whether it can meet the engineering needs in actual use. When selecting an electric device, not only the aforementioned working environment, electrical control and general technical performance should be considered, but also the comprehensive technical performance of the electric butterfly valve device should be fully considered.

1. Allowable value of valve stem diameter

When selecting an electric device for a lifting rod valve, attention should be paid to the diameter of the valve stem that is allowed to pass through, and the diameter of the valve stem must be smaller than this value. In addition, for multi-turn electric devices, requirements for the height of the valve stem cover should also be put forward when selecting them (related to the valve pain diameter). Rotary stem valves are available without stem cover.

2. Connection of valve and electric device
The connection type and size of the valve and the electric device should comply with the national standards: GB/T12222-1989 Connection of multi-turn valve driving devices, GB/T12223-1989 Connection of partial-turn valve driving devices.

3. Output torque and speed of electric device
The output torque value is one of the important technical parameters of the electric device, and it is also an important parameter that needs to be selected during use. If the output torque of the electric device selected when assembling an electric butterfly valve is too large or insufficient, it is not advisable. Because in general, electric device manufacturers need to test and adjust the output torque value before the product leaves the factory, which is relatively accurate. If an excessively large output torque margin is selected, the electric valve will be potentially dangerous. Once control and protection failure occurs, it will easily cause valve damage (valve stem bending, valve body rupture), and easily cause pipeline system accidents. Therefore, it is not advisable to choose an output torque margin that is too large. If the valve cannot be opened in actual work, it is an unreasonable choice.