Tube-Side Header

Fixed-Tube-Sheet Heat Exchang ers Fixed-tube-sheet exchangers (Fig. 11-36Z ) are used more often than any other type, and the frequency of use has been increasing in recent years. The tube sheets are welded to the shell. Usually these extend beyond the shell and serve as flanges to which the tube-side headers are bolted. This construction requires that the shell and tube-sheet materials be weldable to each other. 

The tube-side header (or channel) may be welded to the tube sheet, as shown in Fig. 11-35 for type C and N heads. This type of construc-... 

Tubes can be replaced. Tube-side headers, channel covers, gaskets, etc., are accessible for maintenance and replacement. Neither the shell-side baffle structure nor the bhnd gasket is accessible. During tube removal, a tube may break within the shell. When this occurs, it is most difficiilt to remove or to replace the tube. The usual procedure is to plug the appropriate holes in the tube sheets. 

U-Tube Heat Excbajiger (Fig. 11-36J) The tube bundle consists of a stationaiy 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 integr 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. 

Tube-Side Header The tube-side header (or stationary head) contains one or more flow nozzles. 

Tube-side headers for water sei vice are made in a wide variety of materials carbon steel, copper alloy, cast iron, and lead-hned or plastic-lined or specially painted carbon steel. 

Proce.s.s-side design pre.s.sure. The high-pressure process fluid is always in the tubes. Tube-side headers are relatively small as... 

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