Bolt the flanges

The conventional bolt size for this size flange is however the W bolts just fit in the holes and maintain the alignment of the flanges to each other much better. Either 3A bolts or % bolts will work. 

For either size bolts, be sure that the flanges are aligned properly, and continue with the final tightening of nuts and bolts in a crisscross fashion. 

Do not tighten one bolt completely and then proceed to the next. Just tighten each bolt a little and proceed to the next bolt in sequence. Continue the cycle of bolt tightening until the bolts cannot be tightened any further. 

When tightening bolts, use the correct size wrenches. Use two wrenches to tighten the bolts, one to hold the bolt head and the other to tighten. 

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The gasket, which is really the focal point of the bolted flange connection, is subjected to compressive force by the bolts. The flange... 

Relaxation is an important example of a creep phenomenon encountered in practice. Bolts, studs, flanges, and springs of all kinds are subject to relaxation when used at high temperatures. These members are loaded to a stress that must be maintained for proper functioning. If relaxation occurs, the stress decreases. Thus bolts can become loose so that bolted joints develop leaks after operation at elevated temperatures. 

Figure 7 shows nozzle locations and support arrangements for a typical horizontal vessel (7). The saddles used for support are sustained by concrete pedestals or steel stmctures. Sufficient clearance between the bottom nozzles and the support saddles needs to be provided for access to the nozzle flange bolts. The manway can be located on the end head of the vessel, the topside of the vessel, or the side of the vessel. The preference is for an end manway wherever possible for accessibiHty, except when it is limited by the level gauges and controls that are commonly mounted off the heads. 

Don t use flange bolts to unite misaligned piping to the pump. This damages the flange faces and stresses the pump easing (Figure 17-18). 

Flanged Bolted flange connectors. Figure 40.35, are suitable for most pressures now in use. The flanges are attached to the piping by welding, brazing, tapered threads... 

Full-faced flanges, Figure 13.34a where the face contact area extends outside the circle of bolts over the full face of the flange. 

The forces and moments on the flange must also be checked under the bolting-up conditions. 

A 4 in. ID fire hose discharges water at a rate of 1500 gpm through a nozzle that has a 2 in. ID exit. The nozzle is conical and converges through a total included angle of 30°. What is the total force transmitted to the bolts in the flange where the nozzle is attached to the hose Assume the loss coefficient in the nozzle is 3.0 based on the velocity in the hose. 

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