Safety valve leakage issue
Thread Content
A safety valve is installed on the outlet pipeline of the positive displacement pump, with its discharge port connected to the pump’s inlet pipeline. However, when the pump’s inlet valve is opened, there is leakage of fluid at both the connection surface of the safety valve body and at the position of the top adjustment screw (the pump was not started; the safety valve has been tested). What could be the reasons for this? Is it due to an incorrect installation method, or is there a problem with the safety valve itself? (The same issue occurs with all 4 safety valves installed in this manner.)
Is there any opening in the return line of the positive displacement pump? This causes the inlet pressure of the pump to increase slightly.
Although the poster emphasized that the safety valve had been inspected, I still think the safety valve is defective. As I understand it, the pipeline arrangement mentioned by the poster is a pressure-limiting backflow mechanism designed to prevent overpressure on the outlet side of the positive displacement pump. Under normal conditions, the pipeline on the inlet side of the pump also does not have very high pressure. The fluid enters the outlet side of the safety valve through the return pipe; if low-pressure fluid leaks, it is either because the safety valve was not selected appropriately or because its quality is poor
First of all, there is no problem with the installation of your safety valve. The key is whether the safety valve you choose is suitable for this medium, in terms of temperature, pressure, and the type of medium it can handle. Impurity content in the medium. If the requirements are met, it is best to consult the inspection department to determine whether inspection will be granted after the valve is repaired and the fault is resolved. If possible, before sending it for inspection, disassemble the valve and conduct a thorough examination, with a focus on the sealing of the valve stem (or replacing it with a gland seal). Another issue is that there may be pressure in the backflow stream behind the safety valve, which can cause leakage in the valve stem. It might be possible to alter the path of this backflow in order to reduce the pressure in the backflow pipe behind the safety valve, thereby preventing or minimizing leaks.
If only the flange connection surface is leaking, it might be due to a poor connection. But if there is a leak at the top of the safety valve, then there is a problem with the valve itself
The discharge pipeline behind the safety valve must not be under pressure; if there is pressure, leaks may occur at the position of the upper adjustment screw.
1. The safety valve is installed properly. Was there a wrong selection? 2. Were there too many impurities during the equipment manufacturing process? 3. Was the safety valve truly tested by a qualified testing agency, or did impurities get stuck when the valve activated during testing, resulting in minor leaks?
There is a problem with the safety valve. Also, is your positive-displacement pump a gear pump, which can have a safety valve built in?
The discharge port of the safety valve should not be connected to a pipeline under high pressure
I’ve encountered similar problems as well; if there is pressure at the outlet of the safety valve, leakage can easily occur, but the reason for this hasn’t been identified