Construction of Plates

In two-dimensional solids theory, the size of the solid in a fixed direction is assumed to be small as compared to the other ones. Therefore, all characteristics of the thin solid are referred to a so-called mid-surface, and one obtains the two-dimensional model. Let us give the construction of plate and shell models (Donnell, 1976 Vol mir, 1972 Lukasiewicz, 1979 Mikhailov, 1980). 

Bioautography of developed chromatograms is carried out by similar methods in most laboratories. The authors use Pyrex baking dishes approximately 8.5 in. wide by 13.5 in. long by 1.75 in. deep (21.6X34.3X4.4 cm) with stainless-steel covers. Similar types of flat dishes constructed of plate glass or plastic have also been used by numerous investigators. 

Figure 7.5 is a general survey of the different plate types and their combination in cells of both systems. In Figure 7.6 and Figure 7.7 the most usual plate construction for lead-acid batteries are shown, in Figure 7.8 today s construction of plates for nickel/cadmium cells. 

Aside from road and off-road cars, agricultural vehicles require a much higher effort for the construction of plates and plate packages if a reduced service life... 

FIG. 11-44 Typical construction of a tube bundle with plug headers (1) tube sheet (2) plug sheet (3) top and bottom plates (4) end plate (5) tube (6) pass partition (7) stiffener (8) plug (9) nozzle (10) side frame (11) tube spacer (12) tube-support cross member (13) tube keeper (14) vent (15) drain (16) instrument connection. (API Standard 661.)... 

Vacuum-Shelf Dryers Vacuum-shelf diyers are indirec t-heated batch diyers consisting of avacuumtight chamber usually constructed of cast iron or steel plate, heated, supporting shelves within the chamber, a vacuum source, and usually a condenser. One or two doors are provided, depending on the size of the chamber. The doors are sealed with resihent gaskets of rubber or similar material (Fig. 12-49). 

The Karr column is particularly well suited for systems which tend to emulsify since its uniform shear characteristics tend to minimize emulsion formation. It is also particularly well suited for corrosive systems (since the plates can be constructed of non-metals) or for systems containing significant solids (due to its large open area and hole size on the plates). Slurries containing up to 30 percent solids have been successfully processed in Karr columns. 

Because PVC evolves corrosive hydrochloric acid on heating, care should be taken in the choice of metals for machine construction and the use of plating and/ or special steels is widely practised. 

The filter structure consists of a stack of plates attached to a hollow shaft which are mounted inside a pressure vessel with each plate covered with a suitable filter medium. The slurry is fed under pressure into the vessel and the cake, which is retained by the filter medium, forms on the top of each plate whilst the filtrate passes through the hollow shaft further to the process. Filter sizes may vary but generally the maximum is 60 m area and designed for a 6 bar operating pressure. Each circular plate in the stack is constructed with radial ribs that are welded to the bottom and support a horizontal coarse mesh screen which is covered with a finer woven metal screen or filter cloth to retain the cake. The bottom of the plate slopes towards the hollow central shaft which lets the filtrate flow freely through circumferential holes and further down the shaft to the filtrate outlet. The clearance between the plates is maintained by special spacers with "o" rings to positively seal between the slurry that surrounds the plates and the shaft that collects the filtrate. The height of the spacers determine the clearance for cake build-up and may be replaced to meet various process conditions. 

The vessel is a 15 ft high cylinder with a diameter of 16.25 ft constructed of half-in thick, type 304 stainless steel plate. Six outlet nozzles are uniformly spaced around the circumterence at the bottom, and six tapered inlet nozzles are uniformly spaced around the circumference of the water plenum at the top of the vessel. The primary water system PWS contains 40,000 gal of DjO 24,000 gal in the re tank and 16,000 gal in the piping system. Each of the six primary loi ted... 

Fig. 21 Pnnciple of construction of a photoelement [1]. — 1 light-transmitting metal layer, 2 semiconductor layer, 3 metal plate.

A laminate is a bonded stack of laminae with various orientations of principal material directions in the laminae as in Figure 1-9. Note that the fiber orientation of the layers in Figure 1-9 is not symmetric about the middle surface of the laminate. The layers of a laminate are usually bonded together by the same matrix material that is used in the individual laminae. That is, some of the matrix material in a lamina coats the surfaces of a lamina and is used to bond the lamina to its adjacent laminae without the addition of more matrix material. Laminates can be composed of plates of different materials or, in the present context, layers of fiber-reinforced laminae. A laminated circular cylindrical shell can be constructed by winding resin-coated fibers on a removable core structure called a mandrel first with one orientation to the shell axis, then another, and so on until the desired thickness is achieved. 

Figure 10-180. Typical construction of tube bundles with plug and cover plate headers. (Used by permission Bui. M92-3003MC 10/94. Hudson Products Corporation.)...

Cowan, C. T, Choosing Materials of Construction for Plate Heat Exchangers, Chem. ng ,June 9 (1975) p. 100. 

Manifolds are usually one of three types sandwich, cast, or drilled. The sandwich type is constructed of three or more flat plates. The center plate, or plates, is machined for passages and the required inlet and outlet ports are drilled into the outer plates. The plates are then bonded together to provide a leak-proof assembly. The cast type of manifold is designed with cast passages and drilled ports. The casting may be iron, steel, bronze or aluminum, depending on the type of system and fluid medium. In the... 

The construction of multicylinder machines gives the opportunity to change the working swept volume by taking cylinders out of service with valve-lifting mechanisms. The ring plate suction valve which is located at the crown of a loose liner can be lifted by various... 

Today boiler vessels are usually fabricated from special boiler plate and firebox steels of varying thickness, while their auxiliaries (supplementary equipment) and appurtenances (boiler accessories and instruments, especially those employed for safety reasons) may be produced from any of several different constructional metals, alloys, and other materials, including cast iron, copper alloys, stainless steels, and so forth. Tubes and tube plates may be variously constructed of carbon steel, low-alloy steels, or special alloy steels, with each design providing for particular required levels of thermal and mechanical stress and corrosion resistance. The overall boiler plant system may have a life expectancy in excess of 50 to 60 years, although individual components may need to be replaced periodically during this period. 

The periodic development and use of new steel alloys can improve ferrous corrosion resistance however, where economizer units are constructed of copper alloys, under certain conditions serious copper corrosion problems may result. This occurs when FW having a pH over 8.3 also contains small amounts of ammonia and dissolved oxygen (DO). The ammonia may be present, for example, as a result of the overuse or inappropriate application of certain amines. Further damage may occur from the plating-out of the copper-ammonia ion then created as a cathode on boiler tubes. This promotes anodic corrosion of the immediate surrounding anodic areas. 

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