Lolain4238
Industrial
- Nov 7, 2023
- 5
Hello,
I'm reaching out regarding an issue we’ve encountered with DN40 straight-way check valves (lift type check valves) and would greatly appreciate your input, as we’re running out of hypotheses to explain the phenomenon.
I reported a sealing issue with two check valves installed in an NH3 system. Check valves are mounted in a discharge pump circuit. I observed that the metal sealing surface on the check valve body was severely damaged after only a couple of months, while the PTFE sealing seat remained in excellent condition—a situation I could not explain.
Upon inspection, we confirmed that the metal sealing surface of the valve body was indeed heavily damaged, whereas the PTFE seat was nearly intact. The damage patterns on the sealing surface matched the diameter of the metal piston, suggesting direct metal-to-metal contact. This seemed incompatible with the pristine condition of the PTFE seat.
The check valves have been replaced (body + bonnet top) twice and the same problem keeps occuring.
Informations :
The fluid velocity is near the maximum allowable limit for the pump.
No vibrations nor shattering.
There are no fluctuations in pump speed or pressure
Check valves are compatible with the operating pressure and temperature.
Let me know if you have any idea, it would be much appreciated.
Lolain4238
I'm reaching out regarding an issue we’ve encountered with DN40 straight-way check valves (lift type check valves) and would greatly appreciate your input, as we’re running out of hypotheses to explain the phenomenon.
I reported a sealing issue with two check valves installed in an NH3 system. Check valves are mounted in a discharge pump circuit. I observed that the metal sealing surface on the check valve body was severely damaged after only a couple of months, while the PTFE sealing seat remained in excellent condition—a situation I could not explain.
Upon inspection, we confirmed that the metal sealing surface of the valve body was indeed heavily damaged, whereas the PTFE seat was nearly intact. The damage patterns on the sealing surface matched the diameter of the metal piston, suggesting direct metal-to-metal contact. This seemed incompatible with the pristine condition of the PTFE seat.
The check valves have been replaced (body + bonnet top) twice and the same problem keeps occuring.
Informations :
The fluid velocity is near the maximum allowable limit for the pump.
No vibrations nor shattering.
There are no fluctuations in pump speed or pressure
Check valves are compatible with the operating pressure and temperature.
Let me know if you have any idea, it would be much appreciated.
Lolain4238
