Is it necessary to add support plates at the bends of the U-tube bundle in a U-tube heat exchanger?
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Recently, a U-tube heat exchanger with a diameter of DN700 was designed, featuring baffle spacing of 167 mm, which is already quite small. The sum of the structural dimensions A+B+C at the rear part of the U-tubes, near the elbow section, is less than the maximum support span. The client requested that support plates be added at the elbows of the U-tube bundle; these plates are to have a large circular hole in their center to allow fluid to pass through. As a result, the supporting function of these plates becomes very limited. Dear sailors, do you think it’s necessary?
According to standard 6.8.2.3.4: If the sum of A+B+C is not greater than the maximum unsupported span specified in Table 6-31, the baffle can be installed as shown in Figure 6-25. However, the sum of A+B+C is greater than the maximum unsupported span listed in Table 6-31; in such cases, it is necessary to use supports or reinforce the structure. Of course, if the user requests that the final baffle be equipped with a support structure, that can also be done. The user may be considering not only the maximum unsupported span specified by the standards but also tube bundle vibrations caused by other process conditions. For safety reasons, it is best to follow the user’s requirements, as the standards represent recommendations and merely the minimum requirements.
In fact, it is very difficult to reinforce the end portion of such U-tubes, as the gap between the tubes is quite small, and it is necessary to machine individual sections in the U-shaped part that can be inserted there. It’s too complicated. I wonder if anyone has any better engineering experience regarding this situation? I hope to be able to share it.
Are there any connectors on the back of the support plate? If not, there’s really no need for it; it’s a waste. But just a reminder: a small spacing doesn’t necessarily mean no vibration
Which expert designed this type of tail support? Please share it The U-shaped heat exchanger I designed last time exceeded it. No settings have been set, so I’m not sure what the impact will be.
How could it not be designed according to standards? ? ?
We have encountered the issue of tail support before; calculations showed that A+B+C exceeded the limit, so we designed it following the approach used for support plates without considering it in detail. As a result, the machinery factory found that it was simply impossible to fit it in during the manufacturing process. After much thought, there was really no other solution; I had to make the tail supports into short rods that could be inserted between the gaps in the tube. Because I didn’t make that one, so I don’t know either if it will work well after being used in a vehicle. I think the standard sets a requirement for the maximum value of A+B+C, simply to prevent vibration at the tail end of the U-tube. If there are other ways to prevent vibration, there is no need to make things so complicated. I wonder if any of you sailors have better methods?
Generally, a solid block design is used more often at the tail, and it is in a reinforced version, which is usually also referred to as a support plate. What structure is the other one you mentioned?
I have encountered this situation before; it was suggested by the process team in order to make use of the heat transfer area of the curved section at the back. However, since the maximum unsupported span of that heat exchanger exceeded the specified limits, we informed the process team that it did not meet the standard requirements, and it was modified accordingly. Personally, I think it’s possible to do as you said, as long as the heat exchange tubes do not exceed the maximum unsupported span.