If a tight closure is needed after service, a CBIPL PBR valve for discontinuous service is the proper and best solution.

BLB applications:
operate in open position
control continuous flow of steam and/or water under high pressure

BLB features:
Bonnet less
non-rotating stem (for continuous blow down)
minimizes the effects of a fluid containing abrasive particles
operates with very high Δ pressure
any actuator can be easy assembled