Some gate valves pass the pressure test but leak as soon as they go into service. The problem is often not the valve quality, but incorrect installation or operation.The main gate valves product names of China gate Valve Network include:Manual Knife-shaped Gate Valve,Manual Slurry ValveManual Wedge Copper Gate Valve,Manual Vacuum Isolated Wedge Gate Valve,Manual Welding Vacuum Wedge Gate Valve,Manual Wedge Gate Valve ,With Purge HoleNon-rising Stem Resilient Seat Seal Gate Valve,Non-rising Stem Wedge Cast Iron Gate Valve

1. Poor pipeline cleaning

Weld slag and rust particles hit the sealing surface at high speed, leaving scratches. The standard requires a purge velocity of at least 20 m/s, but this is often ignored. A new valve is damaged before it even runs.

2. Excessive closing force

A gate valve seals by wedging the gate against the seats, not by brute force. Using a cheater bar or long wrench deforms the sealing surfaces or strips the stem threads. When the handwheel stops turning, the valve is fully closed – more force only causes harm.

3. Wrong hot‑bolting sequence

At high temperature, flange bolts elongate and need retightening while hot. If the valve is closed when hot‑bolting, the body distorts and misaligns the gate with the seats. Correct procedure: open the valve a few turns to release stress before tightening flanges.

Quick diagnosis – remove the valve and look at the sealing surfaces. Fine scratches can be lapped; local dents or deformation mean the body is warped and must be replaced.

Prevention – purge lines thoroughly, close the valve by hand without extra levers, and always open the valve slightly before hot‑bolting on high‑temperature systems. Follow these three steps and seat life will double.

Do you still need to know or purchase the following gate valve products:

• Manual Knife-shaped Gate Valve
• Manual Slurry Valve
• Manual Wedge Copper Gate Valve
• Manual Vacuum Isolated Wedge Gate Valve
• Manual Welding Vacuum Wedge Gate Valve
• Manual Wedge Gate Valve With Purge Hole