1, the valve stem diameter allowable value Lift lever VALVE Select electric device should pay attention to its allowable valve stem diameter value, the stem diameter must be less than this value. In addition, for multi-turn electric device, in the selection should also be put forward to the valve stem height requirements (and valve pain diameter). The rotary lever valve is not equipped with a valve stem cover.
2, the valve and the electric device connection The connection type and size of the valve and the electric device shall conform to the national standard: The connection of the gb/t12222-1989 multi-turn valve drive device, and the connection of the gb/t12223-1989 part slewing Valve drive.
3, the output torque and speed of the electric device The output torque value is one of the important technical parameters of the electric device, and it is also an important parameter to be selected in the use. It is undesirable to have too large or insufficient output torque for an electric device to be used in a group with an electric valve. Because of the general situation, the electric device factory in the factory when the output torque value should be measured and adjusted, is relatively accurate. If the use of excessive output torque margin, will make the electric valve has a great potential danger, once the occurrence of control protection failure situation will easily cause valve damage (stem bending, valve body rupture) phenomenon, very easy to cause pipeline system accidents. So it is undesirable to choose too large output torque margin. If you do not open the valve in the actual work is also an unreasonable choice.