Stop valve pipeline purging
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Question: In a pipe equipped with a globe valve, where the liquid flows from the left side through the globe valve (in the correct direction) to the right side, could cleaning the pipe by blowing from the right side to the left side result in incomplete cleaning due to the structure of the globe valve? Thank you
There’s no major issue with this; if the stop valve is fully open, there’s no pressure problem downstream of the valve
Keep the valve fully open; ensure a sufficient purging volume – this has nothing to do with the structure of the stop valve
This purging issue is not serious, but care should be taken to ensure that no solid impurities remain at the valve seal, otherwise it will affect the sealing
It’s important to purge it completely in one go; don’t stop before it’s fully purged!
If the pressure is high enough, it will have no effect on the valve; however, if the pressure is low, it is better to first remove the valve, then purge it, and reinstall it after it is clean.
Backblowing is definitely not good for the globe valve stem; since you insist on blowing, it must be done quickly and accurately. You need to take into account the medium used for purging ； Is it wind or steam? What about its temperature and pressure? Should a filter be installed before the shut-off valve, etc.?
Some types of stop valves cannot be backflushed.
Yes, it’s important to pay attention to the sealing of the stop valve – no foreign objects should be present, as this can affect the sealing performance. Therefore, sufficient pressure is necessary; it’s best to avoid backflow, I think.
Since it is a liquid purge valve, I think this liquid should be quite clean. The function of the blow-off valve is to periodically remove accumulated liquid from the pipes, so the concerns upstairs are unfounded