Flanges closure

Varying the steam-to-condensate interface level to control the reboiler duty will promote steam leaks in the channel head-to-shell flanged closure. This is caused by the thermal cycling and stresses that result from constantly varying the level of condensate in the channel head. However, when low-pressure steam (<60 psig) is used, this becomes a minor problem, which may be safely ignored. 

Fig. 10.11. Metal gasket sealed bolted flange closures. A soft metal gasket, generally made of aluminum or copper, is clamped between knife edges (ci) or stepped flanges (b).

Fig. 10.10. O-Ring sealed bolted flange closure. This type of joint is used for large diameter openings. The groove to receive an O-ring seal is machined so that the depth E is 0% of the O-ring width and Fis 135% of the O-ring width. The extra clearance is on the inside of the groove for applications in which the apparatus is to be pressurized and on the outside of the groove when the apparatus is to be evacuated.

Double Cone/Fluor Double Cone 20,000 12-36 Gasket Matl Depends on configuration Lapping of groove required Use with either threaded or flanged closure... 

Delta Ring 50,000 2-36 Gasket Matl Depends on configuration Tight tolerances and fine finishes required on groove Use with flanged closure only... 

Figure 8.10 Flanged closure 1, screwbolt 2, extensometer 3, nut 4, washer 5, flange 6, doubled cone gasket 7, closure.

Openings in closures over 50 percent in diameter are designed as flanges in flat closures and as reducers in other closures. Openings of not over one-half of the diameter are to be reinforced as branch connections. 

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 hairpin heat exchanger, unhke the removable bundle TEMA styles, is designed for bundle insertion and removal from the return end rather than the tubesheet end. This is accomplished by means of removable spht rings which shde into grooves machined around the outside of each tubesheet and lock the tubesheets to the external closure flanges. This provides a distinct advantage in maintenance since bundle removal... 

Figure 2. Diagram of laboratory reactor (1) glass reactor vessel (2) inlet port (3) outlet port (4) thermocouple port (5) propeller impeller (6) turbine impeller (7) impeller shaft (8) stainless steel center plug (9) Teflon center plug (10) center bolt (11) interface plate (12) flange assembly (13) Chemco reactor support (14) Chemco reactor top closure plate (15) Chemco reactor impeller shaft bearing housing (16) reactor blead port...

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

Figure 26.30 shows details of a gas vent pipe system. The two details at the top left of the illustration show close-ups of the boot seal and flange seals located directly at the interface of the SWCR system with the FMC. To keep the vent operating properly, the slope of the closure system should... 

Flanged openings shall be provided with metal closures at least 5 mm (0.19 in.) thick, with elastomer gaskets and at least four full diameter bolts. For studded openings, all nuts needed for the intended service shall be used to secure closures. 

---