On the inspection and testing of check valves
Thread Content
Dear colleagues, the Jiujiang petrochemical accident has dealt a severe blow to our equipment management. In my opinion, we should consider our equipment management from two aspects: 1. If the lubricating oil pressure of the compressors suddenly drops, what preparations should we make to prevent this? 2. At present, we rely on check valves to prevent the backflow of materials; when the pressure changes from low to high, it is still the check valves that help prevent backflow. However, the reliability of these check valves is currently considered unreliable. How can we assess the reliability of check valves, and what methods can be used to verify it? Does anyone have any good suggestions?
To determine the reliability of a valve, does it have to be tested separately? Sealing test, strength test
In situations where high pressure is connected to low pressure, an emergency shut-off valve should be installed to ensure that the medium can be quickly cut off in the event of a sudden pump shutdown, thereby preventing pressure crossover. Furthermore, the occurrence of the Jiujiang series voltage accident is also closely related to the operations performed by the operators on site. When the flow control at the pump outlet is working properly, the system operates in automatic mode; after the pump stops, it should immediately switch to manual mode and the valve should be closed. I guess the system remains in automatic mode even after the pump stops, which causes the valve to stay fully open. Coupled with leakage from the check valve, that’s… In fact, check valves generally don’t seal properly, but the leakage shouldn’t be that severe.
In situations where high pressure is connected to low pressure, an emergency shut-off valve should be installed to ensure that the medium can be quickly cut off in the event of a sudden pump shutdown, thereby preventing pressure crossover. Furthermore, the occurrence of the Jiujiang series voltage accident is also closely related to the operations performed by the operators on site. When the flow control at the pump outlet is working properly, the system operates in automatic mode; after the pump stops, it should immediately switch to manual mode and the valve should be closed. I guess the system remains in automatic mode even after the pump stops, which causes the valve to stay fully open. Coupled with leakage from the check valve, that’s… In fact, check valves generally don’t seal properly, but the leakage shouldn’t be that severe.
Check valves rarely provide a sealing function, and there are currently no effective methods for testing them; regular disassembly and inspection are the only options.
I also want to figure out how to test a check valve and how to set the pressure ?
Chemical production encounters this issue, especially with large pumps of importance. Objectively speaking, it is easy for high pressure to leak into the low pressure side during pump reversal.
An emergency shut-off valve should be installed; it is not sufficient to rely solely on check valves
Check valves rarely function as seals