Fault analysis of fluorine lined check valve: check valve cannot stop water

    check valve It is one of the commonly used valves in pipeline systems. Recently, I encountered a customer who said that some fluorine lined check valves in pipeline systems sometimes cannot stop water, and even all check valves cannot stop water. Upon disassembling the pipeline for inspection, it was found that there were no foreign objects inside the check valve. However, after installation, the equipment still experienced backflow, and the check valve was unable to stop the water flow. His check valves are newly purchased, and the outlet pressure is also above 0.4MPa. The check valve is located at the outlet of the water pump. When the water pump stops running, the pressure in the pipeline will flow back into the tank behind the pump, and the inlet pressure of the tank is about 0.3 MPa.

So, what is the reason for the failure of the fluorine lined check valve to stop water?
In fact, check valves will have some leakage to some extent, as long as the leakage is within the specified value, it is qualified. The problem of the check valve not being able to stop water mentioned above may be caused by the following reasons:
1. Insufficient pressure difference: Insufficient pressure difference before and after the check valve may cause leakage.
2. Stuck valve seat: The valve seat may sometimes get stuck, causing the spring to malfunction and resulting in poor sealing.
3. Incorrect installation direction: When installing vertically, if the installation direction is incorrect, the valve disc may open by gravity.
4. Mismatch in sealing: The sealing surface does not match the rubber, 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 inadequate sealing when there is a pressure difference.