Double Block & Bleed Saver
Safe working behind leaking valves by installing a vacuum lock
The working principle of the DBB-SAVER is based on active evacuation of the bleed volume, thereby creating a vacuum lock between two sealing surfaces preventing leakage towards the safe work area.
The DBB Saver can be deployed on systems containing hazardous media such as:
- Gasses, e.g. flammable and/or toxic, like natural gas, H2S, hydrogen, etc.
- Liquids becoming gaseous under atmospheric conditions, e.g. LNG, LPG, etc.
- Regular liquids like crude oil, naphta, etc.
The bleed volume can either be the section between:
- Both block valves in a classical DB&B configuration, or
- Both seats in the body of a single valve, e.g. most ball, plug or gate valves, or
- Any other combination of two valves in series, e.g. a block valve and (under conditions) a control valve without traditional isolation credits
The vacuum creates a negative pressure difference towards the safe work area and reverses the flow direction over the second barrier. The guaranteed continuous presence of the vacuum in the bleed section makes leakage to the safe working area physically impossible.