Double Block and Bleed Valve

Double Block and Bleed Valve, also called DBB Valve simply, structured with two ball valves and a Needle Valve inside the valve body. It can provide Dual Isolation without bolting two individual valves. The needle valve can also realize the Pressure Venting trapped in the valve chamber, which can reduce the risks of Leakage hazards.

Double Block and Bleed Valve provides great savings in weight, space and installation time especially in instrument or instrument cage isolation. These savings can be as much as 60% in weight and studies have shown that a 70% installation time saving is also possible. However, the greatest savings are the reduction of leak paths to atmosphere, therefore reducing the risk of the potential hazards.

Dual Isolation is a necessary requirement when maintain  down stream of the first isolation valve. Cavity venting is provided by either a ball or the needle valve so that trapped pressure between the two isolation ball valves can be safely vented. 

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