Hairpin tubes, heat exchanger exchangers

Haas, D. B. 203, 204, 228 Hagen, G. 78, 139 Hair hygrometer 759 Hairpin tubes, heat exchanger 505 --------exchangers 503... 

U-Tube Heat Exchanger (Fig. 11 -36d) The tube bundle consists of a stationary tube sheet, U tubes (or hairpin tubes), baffles or support plates, and appropriate tie rods and spacers. The tube bundle can be removed from the heat-exchanger shell. A tube-side header (stationary head) and a shell with integral shell cover, which is welded to the shell, are provided. Each tube is free to expand or contract without any limitation being placed upon it by the other tubes. 

Type Pfaudlcr type UB, hairpin tube bundle heat exchanger Heat transfer area 5 ft ... 

The Ballestra group uses a combination of U-tube cooler and a shell-and-tube heat exchanger for the cooling of S02/air with ambient air. MM and Mazzoni supply a vertical double-hairpin heat exchanger (a so-called trombone cooler) with air cooling. 

The hot S02/air gas flows through the stainless steel 316 inner pipe and the ambient cooling air through the mild steel outer pipe. The first part of the hairpin cooler is used to preheat the dried process air before it enters the top of the sulphur burner. The Chemiton SOs/air-ambient cooler is a simple single horizontal hairpin double-tube heat exchanger. 

The best known use of the hairpin is its operation in true counter-current flow which yields the most efficient design for processes that have a close temperature approach or temperature cross. However, maintaining countercurrent flow in a tubular heat exchanger usually implies one tube pass for each shell pass. As recently as 30 years ago, the lack of inexpensive, multiple-tube pass capability often diluted me advantages gained from countercurrent flow. 

Figure 9.64. Heat exchanger with hairpin tubes...

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