►Reasons for Leakage:

1. The casting quality of cast iron parts is not high, and there are defects such as sand holes, loose structure, slag inclusions, etc. on the valve body and valve cover.

2. Cold cracking.

3. Poor welding, with defects such as slag inclusions, unwelded, and stress cracks.

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

►Maintenance Methods:

1. Improve the casting quality, and carry out strength test strictly according to the regulations before installation.

2. Valves with temperatures below 0° and 0° should be insulated or mixed with heat, and valves out of service should be excluded from standing water.

3. The weld of the valve body and valve cover composed of welding, should be carried out in accordance with the relevant welding procedures, welding should also be carried out after the flaw detection and strength test.

4. The valve is prohibited to push and put heavy objects, not allowed to use the hand hammer impact cast iron and non-metallic valves, large diameter valves should be installed with brackets.