Regarding the issue of cutting heat exchanger support rings
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The factory replaced the heat exchanger tube bundle; during installation, it was found that the support rings were too large and could not be fitted in. So, the construction team was tasked with using gas cutting and grinding to resolve this issue, as shown in the image. What are the potential hazards of doing this? What should be done under normal circumstances?
The cause of this situation is that the center of the holes in the heat exchange tube row is not concentric with the equipment.
Machine tool machining after plasma cutting and blanking.
Could you please explain it in more detail? I’m not in the equipment business{:1_90:}
I think there shouldn’t be too much of a problem; after all, even if the outer diameter of the baffle is on the larger side, it probably won’t differ by much – at most around 3-5 mm. After cutting it with a flame, all that’s needed is to polish it clean, removing any slag or debris.
I’m not sure how large the area you’ve cut out is. The outer diameter of the baffle is related to the inner diameter of the heat exchanger shell; in other words, both have circular shapes. After you make the cut, the outer diameter of the baffle will definitely become irregular, which can cause the heat exchange tubes and the shell to be out of alignment. This may lead to uneven flow or short circuits of the fluid flowing through the shell side, affecting the heat transfer efficiency. However, judging from your photo, it seems like the problem isn’t serious, as the price difference shouldn’t be that significant. The design margin for heat exchange tubes is generally quite large, so it won’t have a substantial impact on the heat transfer performance
Thank you for your reply. Our equipment was fine at that time; considering your response, I think it’s essential to take proper protective measures during cutting to avoid damage caused by hot metal slag touching the tubes, and also to prevent the grinding wheel from coming into contact with the tubes during grinding. This should be sufficient for us to accept it.
The function of the support ring is to hold the tube bundle in place; therefore, its dimensions cannot be made too small, in order to prevent the tube bundle from moving around inside the shell
You are considering things from the perspective of processing techniques; what you mentioned are things that must be done during the modification process. I, on the other hand, am talking about heat transfer processes. If a similar situation arises in the future, you will also need to consider whether the medium in the shell side is water or steam. If it’s steam, the cutting baffle equipment is prone to producing a whistling sound during operation