Since the electric butterfly valve is composed of butterfly valve and electric equipment, how to select the electric equipment correctly after the butterfly valve is confirmed is an important factor related to whether the project needs can be satisfied in actual use. When selecting electric equipment, not only the above-mentioned operating environment, electrical control and general skill performance should be considered, but also the comprehensive skill performance of electric equipment should be comprehensively considered.
1. Allowable value of valve rod diameter
When selecting electric equipment for lifting lever valves, pay attention to the allowable valve stem diameter value, and the valve stem diameter must be less than this value. In addition, the requirements for the height of the valve stem cover (related to the valve diameter) should also be put forward when selecting multi reversing electric equipment. Rotary stem valves may not be equipped with valve stem covers.
2. Connection between valve and electric equipment
The connection type and size of valves and electric equipment shall conform to national standards: connection of multi reversing valve driving equipment (GB/T12222-1989), connection of reversing valve driving equipment (GB/T12223-1989).
3. Output torque and speed of electric equipment
Output torque value is one of the important skill parameters of electric equipment, and also an important parameter to be selected in use. If the output torque of electric equipment selected when assembling electric valves is too large or insufficient, it is not advisable. Due to the general situation, the electric equipment manufacturer needs to test and adjust the output torque value when the products leave the factory, which is relatively accurate. If excessive output torque margin is selected, electric valve will have great potential danger. Once control and protection failure occurs, valve damage (valve stem bending, valve body cracking) will be easily caused, which is very easy to cause pipeline system accidents. Therefore, it is not advisable to select excessive output torque margin. If the valve cannot be opened in actual operation, it is also unreasonable to select.
As for the confirmation of the output speed of electric equipment, if there is no strict requirement on the opening and closing time of the valve, a slower speed should be selected as far as possible.
Due to the unnecessary fast speed, the motor power will be increased under the same torque requirements, which will not only waste power and improve the project cost, but also increase the volume of electric equipment and cause waste in many aspects.
For the electric equipment developed and developed domestically, there are not many motor standards (generally 2-3 standards) designed for each frame number, and the speed ratio range of gear pair and worm gear pair in the main transmission is limited, so there are not many torque and speed divisions for each frame number.
4. Allowable maximum thrust of electric equipment
If the axial force of the valve is borne by the electric equipment (that is, the valve stem nut is in the electric equipment), the thrust value shall not exceed the allowable value of the electric equipment.
5. Maximum number of turns of valve stem nut
When selecting multi reversing valve electric equipment, it is necessary to clarify the maximum number of turns of the valve stem nut during valve operation, so that the gear speed ratio related to the orientation indication organization in the electric equipment can be correctly selected, so that the orientation indication has a satisfactory accuracy and satisfies the investigation of valve opening and closing degree during valve operation, otherwise it is easy to cause illusion and affect normal operation.
At present, some electric devices of reversing valves have mechanical limits to avoid the inability to judge the orientation of the valve disc. The corresponding connection between the connecting screw hole and the keyway orientation between such valves and electric devices is strict.
