What are the reasons for frequent leakage after replacing the mechanical seal of a high-speed pump? Seek analysis help
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Our company has two high-speed pumps manufactured by Beijing Aerospace Petrochemical Technology Equipment Engineering Company, and they experience frequent leakage issues after new seal replacements； Seeking help from tech experts to resolve this issue ； Now we can be sure that there are no issues with the assembly, and the mechanical seal is in good condition – it’s an original factory-made seal ； There are doubts: I suspect that the low expansion coefficient of the static ring PTFE seal ring prevents it from meeting the sealing requirements; however, the problem persists even after replacing it with a fluororubber O-ring.
It’s also the 11th Aerospace Institute. We have also had multiple leaks; we investigated numerous possible causes, and in the end it was found that the installation was problematic and the positioning was incorrect.
In which aspect does the actual installation take place? Could you share your experience with us? Actually, there’s nothing much inside this pump; it just has many sealing O-rings, and it’s difficult to control the assembly clearance ； We also suspected there might be a problem with our assembly, so we checked carefully, but so far we haven’t found any specific issue at any particular step.
Do you need pictures of the mechanical seals, those produced by Sichuan Ri Ji Research Institute?； The complete on-site assembly diagram can only be provided to you after we disassemble the device next time ；
I also recommend checking the original seal to see its dimensions, especially the inner diameter of the moving ring.
The configuration is the same as ours; is a dry gas seal being used? Ours uses dry gas seals and multiple pumps, and the performance is quite good.
Most of the high-speed pumps used by Beijing Aerospace employ mechanical seals manufactured by Sichuan Niki; it is necessary to adjust the compression amount properly during assembly, and attention should be paid to details such as the installation of the rubber ring behind the stationary ring. Furthermore, the rubber rings supplied by the manufacturer may not be thick enough; the rubber ring on the pump cover in our case is thin and cannot provide a proper seal. We used a makeshift solution by wrapping Teflon tape around the rubber ring and using 704 glue as well, and the result was very good.
Thank you for your detailed reply; next time I disassemble it, I’ll go to the site to take a look
If fluororubber fails due to corrosion and high temperatures, trying to replace it with FFKM seals might be an option