Fixed-Tube-Sheet Heat Exchangers

Construction Codes Rules for Construction of Pressure Vessels, Division 1, which is part of Section T11 of the ASME Boiler and Pressure Vessel Code (American Society of Mechanical Engineers), sei ves as a construction code by providing minimum standards. New editions of the code are usually issued every 3 years. Interim revisions are made semiannually in the form of addenda. Compliance with ASME Code requirements is mandatoiy in much of the United States and Canada. Originally these rules were not prepared for heat exchangers. However, the welded joint between tube sheet and shell of the fixed-tube-sheet heat exchanger is now included. A nonmandatoi y... 

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 U-tube bundle has the advantage of providing minimum clearance between the outer tube hmit and the inside of the shell for any of the removable-tube-bundle constructions. Clearances are of the same magnitude as for fixed-tube-sheet heat exchangers. 

Type Fixed-tube sheet heat exchanger Condensing surface 41.3 ft ... 

Cost as a fixed tube sheet heat exchanger. Section 3.3. 

Condenser shell and tube heat exchanger, fixed tube sheets, heat transfer area 25 m2, design pressure 2 bar, materials stainless steel. 

Figure 8.4. Example of tubular heat exchangers (see also Fig. 8.14). (a) Double-pipe exchanger, (b) Scraped inner surface of a double-pipe exchanger, (c) Shell-and-tube exchanger with fixed tube sheets, (d) Kettle-type reboiler, (e) Horizontal shell side thermosiphon reboiler, (f) Vertical tube side thermosiphon reboiler, (g) Internal reboiler in a tower, (h) Air cooler with induced draft fan above the tube bank, (i) Air cooler with forced draft fan below the tube bank.

Heat exchanger with fixed tube sheets, two tube passes, and one shell pass. (Struihers-WeUs Corporation.)... 

FIG. 11-36 Heat-exchanger-component nomenclature, (a) Intemal-floating-head exchanger (with floating-head backing device). Type AES. (h) Fixed-tube-sheet exchanger. Type BEM. (Standards of the Tubular Exchanger Manufacturers Association, 6tK ed., 1978.)... 

The simplest type of construction for a shell and tube heat exchanger is known as the fixed tube sheet type (Figures 2-1 and 2-2). In this type of unit the distance between the tube bundle and the inside circumference of the shell is at a minimum. The construction is simple, because the tube bundle is welded to the shell. 

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