Reverse buckling disc

There are two basic types of rupture discs the conventional type, which has its concave surface towards the process pressure, and the so-called reverse buckling type, which has its convex surface towards the process pressure... 

Pipefitters have occasionally installed reverse buckling rupture discs upside down. Depending on the rupture disc manufacturer specifications, this usually means that the bursting pressure of the disc will be 50 percent higher than the manufacturer guaranteed as the relieving pressure. Such incidents must have happened at numerous plants and have been whispered about, but seldom documented. 

Figure 6-14 Proper installations of a pre-bulged rupture disc and reverse buckling rupture disc installation. Courtesy of Jim C. Burns, Oklahoma Safety Equipment Company.

Figure 11.25 also shows pressure relief on the column. The normal design pressure for vessels containing liquid chlorine is 15-20 atmospheres. The suction chiller, however, is connected directly to the compressor suction, where the pressure rating is much lower. The relief system on the suction chiller must also protect the compressor. Standard construction is a reverse-buckling Monel rupture disc in combination with a safety valve having Monel internals and a PTFE O-ring seal. 

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