Causes of valve leakage and maintenance methods:

1、 Causes of body and bonnet leakage:

1: There are some defects such as slag inclusion, no welding, stress crack and so on.

2: The casting quality of iron castings is not high, and there are defects such as sand hole, loose structure and slag inclusion on the valve body and bonnet body.

3. The cast iron valve is damaged after being hit by heavy objects.

4. It is cold and cracked.

2、 Maintenance method of valve body and bonnet:

1. The welds of the valve body and bonnet composed of welding shall be carried out according to the relevant welding operation procedures, and the flaw detection and strength test shall be carried out after welding.

2. Improve the casting quality and conduct the strength test in strict accordance with the regulations before installation.

3. It is prohibited to push or place heavy objects on the valve, and it is not allowed to hit the cast iron and non-metal valve with a hammer. The installation of large-diameter valve shall be equipped with a bracket.

4. Valves with air temperature below 0 ° and 0 ° shall be insulated or mixed with heat, and valves out of service shall be drained of water.