(1) Cause of failure:

1. Poor operation causes the closing part to be stuck or exceed the upper dead point, and the connection is damaged and broken;

2. The sealing parts are not firmly connected, loose and falling off;

3, the connection material selection is wrong, can not withstand medium corrosion and mechanical wear.

(II) Troubleshooting method:

1, the correct operation, close the valve do not force too hard, open the valve do not exceed the upper dead point. After the valve is fully opened, the handwheel should be slightly reversed;

2, the closing part and the valve stem should be firmly connected, threaded connection should have a plug;

3. The fasteners used to connect the closing parts and the valve stem should be able to withstand the corrosion of the medium, and have a certain mechanical strength and wear resistance.