Blow Off Valves - Carbon Steel And Chrome Molybdenum Alloy Steel | Multistage Pressure Drop Design, Rising Non-rotating Stem, Optimized For Critical Flow

These valves are usually used when tight seal is needed after a blowoff operation. This utilization could be required by process necessity and/or economical reasons.
In the past the two functions were mostly performed by two different valves, fitted in series and operated in accordance with a definite sequence.

Our valve type PBR carries out both functions in sequence and namely: blowoff with valve suitably open and tight sealing with valve closed.
It is a multistage valve splitting the pressure drop along the whole disk that is along the different stages of the disk. The design of the disk, of the fluid path inside the valve as well the materials are suitable to operation with high Ap, therefore usually with critical flow.

The consequences of these critical flows of water/steam must not affect geometry and finish of the contact surfaces between main disk and main seat in order to ensure tight sealing with the passing of time. The pressure seal bonnet enables easy dismantling, inspection and maintenance . The stem is rising, non-rotating.
The materials used for these valves are shown on page 3 for the most requested Material Schedules, namely: Material Schedule 71 with carbon steel body; Material Schedule 22 with chromemolybdenum alloy steel body. The satisfactory results obtained on all installations confirm the suitability of our design to the most severe operating conditions.