Processing of arc-shaped baffle plates

First, arrange the elements to find the best combination, then place the sample on the board to cut out an arc-shaped piece

How to ensure the concentricity of the tube holes.

When cutting the material, the straight edges of the arc-shaped plate can be made slightly wider; the missing part of the arc-shaped plate can be welded together using carbon steel plates to form a complete circle. After that, it is overlaid on the tube sheet and drilled. Manufacturers have plenty of carbon steel scrap available. Once the holes in the tube sheet are drilled, the carbon steel parts as well as any excess arc-shaped plate material can be removed. Of course, this method is not recommended, as some people might say that carbon steel and stainless steel could suffer from carburization. But I won’t tell you that our company has used this method :P

For bow-shaped baffle plates, it’s never necessary to use a complete circle of material; instead, a single piece of metal is used, which is spot-welded to the baffle plate. Markings are made on this piece, holes are punched, and then drilling is carried out. Finally, the top part of the piece is cut into a bow shape, and assembly proceeds without any problems.

Now, basically no manufacturers use tube sheet stacking with baffle drilling~~~~~~~~~~~~~~

The heat exchange tubes on the tube sheet are first arranged symmetrically about the X-axis. All baffle plates are cut into a single arc shape. Stack them together and drill them all at once. The precision of the drilling machine and the cutting accuracy need to be higher. This ensures that the positions of the tube holes in the heat exchange tubes at the symmetrically arranged tube rows above and below the partition are identical. It’s fine to install the baffle upside down as well. :Lol, but I’ve never seen it done like that; I’m not sure if it will work

Or several separate pieces cut in the same direction of phase change. Drill in two batches. If there are 20 baffles in total. There are 10 with notches on the top and 10 with notches on the bottom. These two sets of ten baffle plates are delivered separately. Drilling 10 baffle plates individually

The heat exchange tubes on the tube sheet are first arranged symmetrically about the X-axis. All baffle plates are cut into a single arc shape. Stack them together and drill them all at once. The precision of the drilling machine and the cutting accuracy need to be higher. This ensures that the positions of the tube holes in the heat exchange tubes at the symmetrically arranged tube rows above and below the partition are identical. It’s fine to install the baffle upside down as well. But I’ve never seen it done this way; I’m not sure if it will work. It’s difficult to ensure concentricity in this way.

I think good manufacturing standards can ensure proper concentricity. Because I encountered such a situation before. My heat exchanger has 76 baffle plates. 9-meter heat exchange tubes. Of course, it’s impossible for all of them to fit together and pass through. It must have been done in batches. The pipes on-site are very easy to put on. However, due to the piping issue, it appears to be X-symmetrical at first glance. But there is one less in the top row. It becomes asymmetric. The workers on site didn’t pay attention, and as a result, one piece was put on backwards. When the heat exchange tube passed through that baffle, there were no holes; the workers thought that holes hadn’t been drilled (they are rather careless). Just leave it there; put on the rest. So the concentricity can be guaranteed. As long as the size of the circular half-piece does not have large errors during cutting.

Should the outer circle of the baffle be turned after the tube holes are machined, or before they are machined?