Bolted cover

Figure 13.9. Flat-end closures (a) Flanged plate (b) Welded plate (c) Welded plate (d) Bolted cover...

No open process or chemical sewer drains should be under or in the drainage zone from a fired process heater since the heater could ignite flammable vapors present in the process/chemical sewer. Where pro-cess/chemical sewer drains are required at a fired heater during cleanup and maintenance, the drain openings should be sealed by a gasketed and bolted cover prior to startup of the heater. 

Figure 59 Eberbach container manufactured for liquid culture. Note bolt covering inoculation hole.

Welded manhole covers provided on process vessels instead of bolted covers— cutting and welding required every time for inspection or cleaning of the internals. This may be very difficult or unsafe if the vessels cany inflammable, toxic, corrosive fluids. 

Welded manhole covers instead of bolted covers which may leak at high pressure). 

PVC cabies encased in soiid drawn heavy-gauge screwed steel conduit terminated at approved enclosures having wide flanges and bolted covers. 

The steam generators have two 8-inch handholes in the lower secondary shell just above the top of the tube sheet and two 18-inch manways in the upper secondary shell above the separator support deck, to permit visual inspection of the tube bundle and personnel access for inspection or repair. The separator support deck has an 18-inch hole with a bolted cover, for access to the top of the tube bundle. The diameter of the handholes has been increased by 2 inches over the handhole diameter for the System 80 steam generators (see CESSAR-DC Section 5.4.2). Nitrogen is supplied to displace water and oxygen and maintain a overpressure of 5 psi when the secondary side of a steam generator is drained but not open for maintenance, in order to protect the tube bundle from corrosion (see CESSAR-DC Section 9.5.10.3). 

Gaskets should be CAF/AR/PTFE of minimum 6 mm thiekness. (Bolted cover facilitates easy maintenance/replacement of agitator, baffles, etc.)... 

WWER NPPs are equipped with horizontal steam generators (SG). Two cylindrical collectors (hot leg and cold leg collector) form part of the boundary between the primary and secondary circuit in a SG. Tubes are attached to these collectors. The WWER-440 SG collectors are made of austenitic stainless steel, the WWER-1000 SG collectors are made of clad carbon steel. There is a bolted cover on the top of the collector (primary pressure boundaiy) and on the shell above the collector cover (secondary side). 

Connector tube Support bolt cover Support bolt Main housjng Ring magnet Pole piece Core bearing Magnet core... 

AU top fittings are mounted on a 20-bolt cover plate, inside a protective housing (bonnet)... 

During the optical coat work stress examination method the upper plate of the head of some of the bolts was covered with an optical coat work (Fig. 4). On the head of some other bolts strain gauges were stuck which measured the plain biaxial stress state in the middle of the top surface of the head of the bolt (3.5 x 3 mm). The magnetic probe detected average stresses up to 0.1 mm depth in an area of 14 mm diameter in the middle of the head of the bolt. 

Yokes. The need to couple the end cover to the body of the vessel may be avoided if yokes, external to the vessel, are used to resist the load arising from the internal pressure acting on the closures. However the necessity to move the vessel out of the yoke and remove one of the closures to gain access to the inside of the vessel limits its use for chemical process equipment. Yokes may be pinned, welded, bolted, or wire wound. Both the vessel and yoke maybe wire wound (136). 

The other space-saving approach is to use the Kobe (Kobe Steel) type of channel enclosure, which does not have all the external head bolts of typical TEMA Type B or Type C head enclosures. These exchangers require special tools to remove the tube bundles and trained maintenance personnel to do the work. These exchangers should never be located in stmctures because of the need to be able to access the channel from grade as it is difficult to remove the channel cover plate by using special equipment. 

Fig. 4. Bomb reactor for the reduction of UF with Mg by the Ames process (capacity 144.2 kg uranium metal) A, steel cover flange with lifting eye B, bolt and nut C, top flange of bomb D, graphite cover E, liner of fused dolomitic oxide F, steel bomb, and G, charge, where represents steel, D liner, ...

To complete the assembly of a cell, the interleaved electrode groups are bolted to a cov er and the cover is sealed to a container. Originally, nickel-plated steel was the predominant material for cell containers but, more recently plastic containers have been used for a considerable proportion of pocket nickel-cadmium cells. Polyethylene, high impact polystyrene, and a copolymer of propylene and ethylene have been the most widely used plastics. 

In accordance with hsted standards, blind flanges may be used at their pressure-temperature ratings. The minimum thickness of nonstandard bhnd flanges shall be the same as for a bolted flat cover, in accordance with the rules of the ASME Boiler and Pressure Vessel Code, Sec. T11. 

Fig. UW-13.2. UA-4S to 52. UA-SS. Fig. UA 48. Appendix S Bolted flange. Spherical cover UA-6 Manhole cover plate. UG-11. UG-46 Flued openings. UG-32. UG-38. Fig. UG-38 Yoke. UG-11...

Unstayed flat heads and covers can be designed by very specific rules and formulas given in this subsection. The stresses caused by pressure on these members are bending stresses, and the formulas include an allowance for additional edge moments induced when the head, cover, or blind flange is attached By bolts. Rules are provided for quick-opening closures because of the risk of incomplete attachment or opening while the vessel is pressurized. Rules for braced and stayed surfaces are also provided. 

The floating-head cover is usually a circular disk. With an odd number of tube-side passes, an axial nozzle can be installed in such a floating-head cover. If a side nozzle is required, the circular disk is replaced by either a dished head or a channel barrel (similar to Fig. 11-36/) bolted between floating-head cover and floating-tube-sheet sldrt. 

The second most commonly used header is a cover-plate header. The cover plate is bolted to the top, bottom, and end plates of the header. Removing the cover plate provides direct access to the tubes without the necessity of removing individual threaded plugs. 

Software In some programmable electronic systems (PES), errors are much easier to detect and correct than in others. Using the term software, in the wider sense, to cover all procedures, as distinct from hardware or equipment, some software is much friendlier than others. Training and instructions are obvious examples. As another example, if many types of gaskets or nuts and bolts are stocked, sooner or later the wrong type will be installed. It is better, and cheaper in the long run, to keep the number of types stocked to a minimum, even though more expensive types than are strictly necessaiy are used for some applications. 

Slides Covering pipelines with polymeric films cathodic protection of pipelines, ships, etc.. With zinc bracelets use of inert polymers in chemical plant galvanic corrosion in architecture (e.g. A1 window frames held with Cu bolts) weld decay. 

In the pull-through, floating-head design, the floating-head cover is bolted directly to the floating tubesheet. This allows the bundle to be removed from the shell without removing the shell or floating-head covers, which eases inspection... 

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