There are Sanitary Diaphragm Valve valves with the same specifications, and they are used under the same working conditions. After installation, the air source was connected, and the pressure was 4.5 kg. One of the pneumatic sanitary diaphragm valves did not move. Later, the air source pressure was increased to 8 kg, but the valve still did not move. The on-site technicians were puzzled.

The sanitary diaphragm valve manufacturer found that when the air source was input, no gas was discharged from the exhaust hole. The preliminary analysis showed that the exhaust hole was blocked. Later, the cylinder cover was opened and it was found that there was foreign matter in the cylinder of the sanitary diaphragm. It turned out that the on-site personnel accidentally pushed the dust cover into the cylinder piston cavity during installation, sealing the exhaust hole, resulting in the inability to discharge gas, the piston was blocked, and the valve did not move. Finally, the foreign matter was removed and the valve worked normally. Therefore, when installing a pneumatic sanitary diaphragm valve, it is necessary to strictly follow the requirements of the instruction manual to avoid unnecessary failures.