4. Experience summary Although it is impossible to determine whether the hidden danger is caused by the process conditions or not, it gives us experience and lessons. During the maintenance, we should focus on the inspection of the upper and lower guide sleeves and connecting pins. However, analyzing the cause of the failure from the structure of the control valve is also a key item of our maintenance work. We should not only repair the existing failure but also judge the cause of the failure, feedback the information to the user, and avoid unreasonable structure in the selection of the control valve during the expansion and transformation of the device in the future.

Fourth, it can better cut off or limit the pipeline flow. As we all know, the advantage of butterfly valve lies in its opening and closing speed. For the first time, it has the advantages of simple structure and low production cost, but its pressure bearing capacity is somewhat lacking. But in the enterprises that control the flow line, they want to be widely used, such as oil, steel making, metallurgy and other industries in Kazakhstan. Its structural feature is that it allows the valve to be pressurized on both sides, and can use up and down rams.