3 Treatment method and result Take out the upper valve cover guide sleeve and rework it to make the gap between the guide sleeve and the valve core guide within 0.1mm, and the coaxiality is 0.02mm. When machining the inner hole, increase the rotating speed of the lathe to reduce the cutting amount, so that the surface roughness reaches Ra1.6, improve the smoothness, and reduce the friction force of the valve stem during operation. After the maintenance, the concentricity of the valve core and valve seat is improved and the vibration of the valve core is reduced. However, such treatment method still cannot fundamentally solve the problem. It is only to ensure the use to the next maintenance cycle. However, such damage to the control valve is caused by the unreasonable structure of the control valve. When the pressure difference is large, we should choose sleeve valve or ball valve. If the medium temperature is high, soft sealing is not suitable. Then we should give priority to sleeve valve.

The electric butterfly valve is characterized by simple structure, small volume, light weight, low material consumption, small installation size, rapid switch, 90 ° reciprocating rotation, small driving torque, etc. It is widely used in the industrial process automatic control system of food, environmental protection, light industry, petroleum, chemical industry, teaching equipment, paper making, power and other industries.