What are the differences between eight-character blind plates, split blind plates, and ordinary blind plates? ?

It’s a pretty simple question, right? Baidu Baike

Sir, I mainly don’t know in what situations it can be used? Such as separate blind flanges

As discussed before, considering the size specifications, it’s too large and heavy, causing torque on the pipes.

Sir, which one should be chosen for low-temperature pipelines or highly corrosive environments? ?

Can an 8-character blind plate be used to open and close pipes, similar to a valve? Can the blind plate rotate?

I’m not good at this. 8-character blind flanges require bolt removal when switching, but they are more reliable than valves. You can search for relevant posts; it should be helpful.

It mainly depends on the size, I guess

This post was last edited by ylb913 on 2016-6-15 at 12:17. What you’re referring to is the difference in application scenarios between eight-character blind plates and separate blind plates. In the case of low-temperature pipelines or highly corrosive environments, when using eight-shaped blind flanges, the part that is exposed to the outside will suffer from corrosion over time. By the time it’s time to replace the blind flange, that exposed ring or portion has already become too corroded to be used, so separate flanges or rings are required; the half that isn’t in use can then be stored in a warehouse. Then, the difference between standard eight-character blind flanges or split blind flanges and ordinary blind flanges is discussed. This relates first to thickness, as well as to the pressure resistance rating. If a thicker blind flange is required, using an ordinary thinner blind flange means that its pressure resistance capacity is insufficient. The next factor is the size of the gap between the flanges. If you do not use standard dogbone blind plates or split gaskets between the two flanges in advance, and instead simply press the flanges together, adding a blind plate on a temporary basis when needed, then you will face difficulties if a blind plate with a greater thickness has to be used, as it may be impossible to pry such a large gap open. The final point is: blind flanges should be included in the piping design from the start (these should be eight-shaped blind flanges, or split-type flanges or rings, chosen based on the specifications regarding thickness), so that those who don’t know the proper procedures won’t think it’s sufficient to simply cut a piece of plate to block something off. I’ve actually experienced this once: a 4 or 6 mm blind flange on a DN100 liquefied gas pipeline couldn’t be removed because it had been compressed into a spoon shape.

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