High pressure closures flanged

Cracking flanges can be particularly hazardous when the upstream isolation valve is plugged. Deposits trapped in the valve seat may inhibit valve closure. The deposits may loosen and break free once the flange is cracked. In one accident (7), this sequence of events was followed by a release of high-pressure liquid butane, after bolts in the housing of the bottom pump suction screen were loosened (without blinding). The release fired and exploded. 

Case 1 High pressure at outlet of well High pressure mainly due to closure of the main S/D valve at the inlet to the main separator. The closure of this valve will result in all lines from the wells and the manifold to over pressuring. This will likely result in a flange rupture at the main manifold assembly leading to a fire and equipment damage PSHL-01 2 FLV-01 Closes None... 

Lens Ring Normally used on small flanges. As the internal pressure increases, it acts on the inside surface of the ring, and forces it to the edge of the cone. Pressures as high as 45,000 psi have been obtained for very small sizes. Often considered one of the fastest opening closures. 

---