Fault Analysis Of Fluorine-lined Check Valve: Check Valve Cannot Stop Water

Lined Check Valve is one of the commonly used valves in the pipeline system. Recently, the editor met a customer who said that some fluorine-lined check valves in the pipeline system sometimes cannot stop water, and even all check valves cannot stop water. After disassembling the pipeline for inspection, it was found that there was no foreign matter inside the check valve, but the equipment still had backflow after installation, and the check valve could not stop water. These check valves were newly purchased, and the water outlet pressure was also above 0.4MPa. The check valve is located at the outlet of the water pump. When the water pump stops running, the pipe network pressure will flow back into the tank behind the water pump, and the water inlet pressure of the tank is about 0.3MPa.

So, what causes the failure of the fluorine-lined check valve to stop water?
In fact, the check valve will leak more or less, as long as the leakage is within the specified value, it is qualified. The problem of the above-mentioned check valve not being able to stop water may be caused by the following reasons:
1. Insufficient pressure difference: The pressure difference before and after the check valve is not enough, which may cause leakage.
2. The valve seat is stuck: The valve seat may sometimes get stuck, and the spring does not work, resulting in poor sealing.
3. Wrong installation direction: When installing vertically, if the installation direction is wrong, the valve disc may open by gravity.
4. Seal mismatch: The sealing surface and rubber do not match, resulting in leakage.
5. Pipeline impurities: The water contains fine sand and gravel, which affects the reset of the fluorine-lined check valve, resulting in poor sealing at the contact position between the valve core and the valve body, and poor sealing when there is a pressure difference.