Baffle type
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Spiral baffle heat exchanger: The spiral baffle heat exchanger (Figure 2) is a type of shell-and-tube heat exchanger that has been developed recently; it was proposed by the American company ABB. In shell-and-tube heat exchangers, the shell side is usually the weak link. The American company ABB has proposed a completely new solution that uses spiral baffle plates. The basic principle is as follows: specially designed plates with a circular cross-section are installed in a \"pseudo-spiral baffle system\", with each baffle occupying 1/4 of the cross-sectional area in the shell side of the heat exchanger; their inclination is directed toward the axis of the heat exchanger, that is, they form a certain angle with respect to the heat exchanger’s axis. The perimeters of adjacent baffle plates meet, forming a continuous spiral shape at the outer circumference. Each baffle is positioned at an angle to the flow direction of the fluid in the shell side, causing the fluid there to move in a spiral pattern. This reduces the dead zones where scaling is likely to occur between the tube sheet and the shell, thereby improving heat exchange efficiency. Due to the spiral flow of the medium, a velocity gradient is generated in the radial direction, resulting in radial turbulence. This completely changes the fluid flow pattern and flow field distribution in the arc-shaped baffle heat exchanger, reduces the thickness of the stagnant layer on the surface of the heat transfer tubes, increases the heat transfer coefficient, eliminates the heat transfer dead zones caused by the arc-shaped baffles, and significantly improves the heat transfer conditions in the shell side. Furthermore, the spiral baffle structure can accommodate a wide range of process conditions, offering great design flexibility; the optimal helix angle can be selected for various specific process conditions. Is there any difficulty in manufacturing spiral baffle heat exchangers? Are there any disadvantages?
The manufacturer said it doesn’t seem difficult to manufacture
Processing baffle plates must be somewhat difficult; special molds are required
Upon careful thought, it’s true; either it has to be enlarged to a circular shape, or holes should be drilled at an angle and then the excess material removed
This baffle is not circular but elliptical, and the holes through which the heat exchange tubes pass are also not perfectly round but have an angle; as a result, the manufacturing precision required and the associated costs are very high
The road ahead is long and arduous; I’ve learned something from this
It’s no longer a difficult issue in China these days!
The heat exchange efficiency might be better, but aligning the tube holes would likely become much more difficult, increasing the manufacturing complexity. Generally, baffle plates are manufactured using CNC or templates to precisely position the layers of baffles and their holes relative to the tube sheet. After helixing, the hole positions are in three-dimensional space, making it difficult to align them accurately during machining.