Shell supported steel

Figure 48-3 Concrete chimney with shell supported steel or FRP liner (shown as tension supported).

Support Plate on Open Shell Unit Steel 1 Thick Reference Print ... 

Since lugs are eccentric supports they induce compressive, tensile, imd shear forces in the shell wall. The forces from the eccentric moments may cause high localized stresses that are c ombined unth stresses from internal or e.xternal pressure. In thin-walled vessels, these high local loads have been kn(rwn to physically deform the vessel wall considerably. Such deformations can cause angular rotation of the lugs, which in turn can caii.se angular rotations of the supporting steel. 

The girder is analyzed as a closed horizontal ring acted upon by the horizontal shear stresses in the tank shell and by the horizontal components of the stresses in the rods and posts in the top panel of the supporting steel framework. 

The shield building roof is a steel and concrete conical shell supporting the PCS water storage tank and air diffuser. Air intakes are located at the top of the cylindrical portion of the shield building. The conical roof is constructed with a stainless steel liner. The air diffuser in the centre of the roof discharges containment cooling air directly upwards. 

The steel shell that encloses the refractory is exposed to significant forces from the expansion of the refractory as well as the load from the refractory and the charge within the furnace. Similarly, the stmctures that support the furnace and the foundations must be designed to assure safe operation. A failure of any component can have serious consequences. 

Fig. 2. Downs cell A, the steel shell, contains the fused bath B is the fire-brick lining C, four cylindrical graphite anodes project upward from the base of the cell, each surrounded by D, a diaphragm of iron gau2e, and E, a steel cathode. The four cathode cylinders are joined to form a single unit supported on cathode arms projecting through the cell walls and connected to F, the cathode bus bar. The diaphragms are suspended from G, the collector assembly, which is supported from steel beams spanning the cell top. For descriptions of H—M, see text.

Furnace Design. Modem carbide furnaces have capacities ranging from 45,000 t/yr (20 MW) to 180,000 t/yr (70 MW). A cross-section of a 40 MW furnace, constmcted in 1981, having a 300 t/d capacity is shown in Figure 2. The shell consists of reinforced steel side walls and bottom. Shell diameter is about 9 m and the height to diameter ratio is shallow at 0.25 1.0. The walls have a refractory lining of 0.7 m and the bottom has a 1-m layer of brick topped by a 1.5-m layer of prebaked carbon blocks. The steel shell is supported on concrete piers and cooling air is blown across the shell bottom. A taphole to withdraw the Hquid carbide is located at the top of the carbon blocks. 

The violent motion of a fluidized bed requires ample foundations and sturdy supporting struc ture for the reactor. Even a relatively small differential movement of the reactor shell with the lining will materially shorten refractoiy life. The lining and shell must be designed as a unit. Struc tural steel should not be supported from a vessel that is sub-jec t to severe vibration. 

The shell may be of metal (steel, alloy, or non-ferrous), plastic, wood or some combination which may require the addition of liners or inner layers of rubber, plastic or brick. The mechanical problems of attaching inner nozzles, supports and brick require considerable attention that is not an integral part of sizing the equipment. Figures 9-2A-C show a typical large steel brick-lined-membrane lined tower with corbeled brick support locations. In these towers, temperature and/or corrosive conditions usually dictate the internal lining, and the selection of the proper acid- (or alkali-) proof cements. 

Care must be taken regarding the method of supporting ceiling panels. Large portal framed steel holdings may provide a cheap outer shell but do have a considerable amount of roof movement. Panels hung from this type of structure can be subjected to movement which cannot be tolerated in cold store construction. A tied portal, however, can be acceptable [38]. The outer shell may also be required to bear the weight of the evaporators and, in the case of stores for carcase meats, the rails and the product itself. 

Further boiler design developments produced various other types of compact, self-supporting, externally fired FT boilers, with the shell mounted over a steel-encased furnace. These designs were loosely called economic boilers and were typically coal- or oil-fired, three-pass boilers with an arched top (the crown sheet) and stayed side-sheets and other flat steel surfaces. 

Make a preliminary mechanical design for the vertical thermosyphon reboiler for which the thermal design was done as Example 12.9 in Chapter 12. The inlet liquid nozzle and the steam connections will be 50 mm inside diameter. Flat plate end closures will be used on both headers. The reboiler will be hung from four bracket supports, positioned 0.5 m down from the top tube plate. The shell and tubes will be of semi-killed carbon steel. 

The shell of a rotary dryer is usually constructed by welding rolled plate, thick enough for the transmission of the torque required to cause rotation, and to support its own weight and the weight of material in the dryer. The shell is usually supported on large tyres which run on wide rollers, as shown in Figure 16.10, and although mild steel is the usual material of construction, alloy steels are used, and if necessary the shell may be coated with a plastics material to avoid contamination of the product. 

The stack was constructed of an inner liner of hrick shrouded hy a concrete outer shell constructed of reinforced steel and concrete. The hrick and mortar liner had no reinforcing steel to support the assembly from side loading. The concrete shroud was primarily for protection against wind. A space of a few feet existed between the wall of the brick liner and the outer concrete shroud. The brick wall was about 3 to 4 feet thick at the bottom, and the wall thickness lessened with height. The concrete portion was of a similar design. 

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