Have your pipes frozen like this before?
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A few months ago, we stopped the operation, flushed the external pipes thoroughly with large amounts of industrial water, and blew them with compressed air to prevent freezing. We also removed the flanges at several low points on the external pipes to drain water – indeed, many measures were taken. But recently, the pipes still get frozen when in use. The most annoying thing is that there are two areas where freezing is particularly severe: 1) A section of pipe with a recessed shape – the areas below the elbows on both sides are not frozen, but the horizontal part of the pipe is frozen! We made a far-fetched explanation: the horizontal pipe at the high point is too long and not level. . . The ice above the elbow has come up from the rising water. . . 2. There is another similar case: the horizontal pipes and vertical pipes at a higher elevation, as well as some of the horizontal pipes, froze up. A flange near one of the sides that was frozen was removed, and there is a DN50 drain valve there; it’s impossible for water to remain in the frozen sections. . . I really can’t figure it out. Who can I turn to and trust? It’s so frustrating! Who can explain this? Does anyone have a better solution? It seems that all the flanges will need to be removed next time. .
It depends on what material is flowing through your pipeline; some materials cannot be cleaned thoroughly by blowing
Usually, when the pipes freeze, I heat them with steam; I haven’t really paid attention to exactly where the blockage is. I’ll figure it out next winter – I need to learn more first
For the first point, a drain valve should be added at the lowest point of the recessed area to facilitate the drainage of all water. For the second point, it seems that area is a dead corner; as a result, water doesn’t get drained from there. Suggestion: In fact, as long as there is a drain valve at the lowest point to reduce the number of dead corners in the piping, or a drain valve should be added at those dead corners as well
When using wind to blow, if the pressure is not sufficient, it may not clean thoroughly
Regarding the first phenomenon, I’m not sure if there is any pressure release point in the horizontal direction of your concave section. For the second phenomenon, check whether there are blockages in your pipelines that prevent proper cleaning, or whether the pipelines are not level. It is recommended to install connecting valves on the inlet and outlet pipelines; this reduces the risk of freezing. The downside is that it leads to some water waste.
Agree with the views from the 5th and 7th floors. In the first case, it’s possible that a vacuum is created at the horizontal pipe in your area; the condensate water then stays there, forming a column of water that cannot flow to lower areas. In the second case, it’s possible that there is just a dead corner there that curves upward. Personally, I think there is a third possibility: it could be due to the operators. 1. The air purging was not carried out in a timely manner, resulting in some areas freezing over. 2、Failing to disconnect the flange in a timely manner may result in water not being drained promptly.
I think the reason is that the pipeline is too long and has too many bends, making it difficult to clean thoroughly. It should be disconnected more often, and blown on section by section. Ensure wind pressure. Ensure the purging time.
I think it was because proper inspection wasn’t done during drying; for very long pipelines, steam should be used for drying
For longer pipelines like this, we usually fill them with diesel. If the wire is not suitable for oil filling, blow on it vigorously with air, then remove the sections along the way and blow on them as well. It’s quite common to experience frost lines like yours; horizontal pipes tend to hold water, and it’s hard to ensure that there’s no water in the wind as well
What is mentioned here is a result, with too many causes at play. It’s hard to put into words. It’s troublesome when the pipelines freeze. If it affects the system startup, you’ll face consequences. The condition of the system often changes, requiring a thorough understanding of it. When handling it, don’t be afraid of trouble and be careful at every step to avoid such frustrating situations.
Perhaps the location where freezing occurred was misidentified; last year, our water pipelines also froze, so we installed temporary pipelines.
The permission to add points is unavailable today; some people were not able to add points. Thank you all for your concern! It was finally completed today; thankfully, it didn’t delay my driving. Thank you to our section leader and fellow workers who worked tirelessly for two days and one night in temperatures near minus 20 degrees! It’s so strange due to the cold – who can I turn to and ask for belief? Especially with leaders – it’s a bit easier to deal with managers, as preventive measures can be taken in advance; such problems often arise when starting the car after it has been parked over winter. . . . In the future, it’s better to go to the extra trouble of finding more drainage points. Reasons: 1. At the higher locations, there is a dead corner with a tee connection where glue has accumulated; this caused the water to back up when drainage occurred. 2. The freezing near the drain valve might be as the HuYang moderator suggested. Additionally, there could be impurities inside the pipes, which accumulated in those dead corners during water back-up and air flushing, and these impurities ended up blocking the inlet of the drain valve during drainage. Once this period is over, open it up and check it
It is likely that the process was stopped before the pipes were completely purged; the water remaining in the pipes gradually flowed back to lower areas where it froze. Therefore, it’s best to install more drain valves in longer pipes.