Type of shells

The heart of a slell and tube cKchanger is ihe shell and the tube bundle inside it. Hast transfer between tube and shell side Duid happens inside the shell at tube s surface. Shell is a cylindrical barrel to house the tube bundle. The iiiost conunod TEMA shell type is E type. 

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Figure 11-36 shows details of the construction of the TEMA types of shell-and-tube heat exchangers. These and other types are discussed in the following paragraphs. 

The simplest type of shell-and-tube heat exchanger is shown in Eigure 3-1. The essential parts are a shell (1), equipped with two nozzles and having tube sheets (2) at both ends, which also serve as flanges for the attachment of the two channels or beads ( 3) and their respective channel covers (4). The tubes are expanded into both tube sheets and are equipped w nil transverse baffles (5) on the shell side for support. The calculation of the effective heat transfer surface is based on the distance between the inside faces of the tube sheets instead of the overall tube length. 

In. sclcciing an exchanger, one must know the advantages and disadvantages td each type. The three basic types of shell-and-tube exchangers are fixed tube sheet, floating head, and U-tube, Table 3-1 summarizes the comparison between these three exchangers. 

The type of shell of an exchanger should often be established before thermal rating of the unit takes place. The shell is always a function of its relationship to the tubesheet and the internal baffles, figures 10-1, 10-2, and 10-3 summarize the usual types of shells however, remember that other arrangements may satisfy a particular situation. 

The actual number of tubes to be installed in the unit. Manufacturing tolerances may require elimination of some tubes that preliminary design layouts and tables indicated might be installed in the unit. Figures 10-25A-Kand Table 10-9 have considered known fabrication tolerances. Sometimes extra tie rods for baffles must be added, or in some cases, eliminated. The outer tube circle limit for each exchanger is determined by the type of shell to be used. That is, (1) if commercial pipe, greater out-of-round tolerances might be required or (2) if formed on shop rolls, the out-of-round tolerance will be known, but not necessarily the same for each diameter shell. 

A type of shell and tube heat exchanger that condenses exhaust steam and creates a vacuum, improving the efficiency of a turbine. 

The principal types of shell and tube exchanger are shown in Figures 12.3 to 12.8. Diagrams of other types and full details of their construction can be found in the heat-exchanger standards (see Section 12.5.1.). The standard nomenclature used for shell and tube exchangers is given below the numbers refer to the features shown in Figures 12.3 to 12.8. 

The simplest and cheapest type of shell and tube exchanger is the fixed tube sheet design shown in Figure 12.3. The main disadvantages of this type are that the tube bundle cannot be removed for cleaning and there is no provision for differential expansion of the shell and tubes. As the shell and tubes will be at different temperatures, and may be of different materials, the differential expansion can be considerable and the use of this type is limited to temperature differences up to about 80°C. Some provision for expansion can be made by including an expansion loop in the shell (shown dotted on Figure 12.3) but their use is limited to low shell pressure up to about 8 bar. In the other types, only one end of the tubes is fixed and the bundle can expand freely. 

Basic Principles. Egerton (47-50) has given admirable summaries of the background theory and the equations required for quantitative application of EELS to the determination of specimen composition suffice it to note that ionization energies depend upon the type of shell (K, L, etc.) and upon the atomic number (Z) of the atom involved. Their values have been accurately... 

The Russians also used during WWII several types of shells with shaped charges. See Figs shown on p Rus 15 of Ref 43... 

Chemical mortar is a weapon(see under CANNONS) designed to fire shells contg toxic or harassing chemicals, substances producing screening smokes, or incendiaries. These shells are called chemical mortar shells. The term "chemical mortar is somewhat obsolete, because current US mortars are capable of firing, besides expl types of shells, also chem types(Refs 1,2 4)... 

FIGURE 4 Standard notation system for major types of shell-and-tube heat exchangers. [From Tubular Exchanger Manufacturers Association Standards. (1988). 7th ed. TEMA, New York. 1985 by Tubular Exchange Manufacturers Association.]... 

Figure B.l Type of shell-and-tubes heat exchangers following TEMA standards [1].

Fig 21b Line drawing of a standard type of shell and tube heat exchanger (courtesy of Patterson-Kelley Co.)... 

A second factor involves the usage of the term Tyrian purple. We have restricted it here to a particular type of shell purple that is... 

In Africa almost any type of shell - including those of land snails -has been used as jewellery, and strung like beads to make necklaces, bracelets or anklets. Shells are still a popular form of adornment, and are often combined with other organic materials such as feathers, or with brightly coloured glass beads. 

As a building block for simulating more complex and practical membrane reactors, various membrane reactor models with simple geometries available from the literature have been reviewed. Four types of shell-and-tube membrane reactor models are presented packed-bed catalytic membrane reactors (a special case of which is catalytic membrane reactors), fluidized-bed catalytic membrane reactors, catalytic non-permselecdve membrane reactors with an opposing reactants geometry and catalytic non-permselective membrane multiphase reactors. Both dense and porous inorganic membranes have been considered. 

British System — The three classes of British chemical shell were distinguished from each other and from all other types of shell by distinctive body colors, as follows gas shell were painted gray smoke shell, light green and incendiary shell, red. In addition, for gas shell, the kind of gas filling was indicated by a system of colored stripes encircling the body of the shell as follows ... 

With this type of shell construction. It Is essential that the shell case be quite full, for It Is the contents of the shell that provide, to a large extent, the strength and rigidity of the shell The case really just defines the shape - It does not supply the strength The case Is filled to the top of the Inner tube A disc Is then pressed down upon the Inner cardboard tube, and the paper extending above the disc Is pleated down uoon It Another disc Is positioned over the folded paper ... 

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