Ball Type Double Block and Bleed (DBB) Valve
Resistant
Sealing
Operation
Long Life
Alis Valves offers high-performance Ball Type Double Block and Bleed (DBB) Valves designed to provide double isolation and safe pressure venting in a single compact unit. These valves eliminate the need for multiple valves, reducing installation space and potential leakage points. Widely used in oil & gas, petrochemical, and high-pressure systems, DBB valves ensure maximum safety during maintenance and operation by isolating both upstream and downstream flow while allowing pressure bleed-off.
Specifications
Ball Type
Floating / Trunnion Mounted
Pressure Rating
Class 150 to 1500
Seat Material
PTFE / RPTFE / PEEK / Metal Seated
Operation
Lever / Gear / Pneumatic / Electric Actuated
Media
Oil, Gas, Chemicals, Hydrocarbons
Size Range
DN 15 to DN 300
Body Material
Carbon Steel / Stainless Steel / Alloy Steel
End Connection
Flanged / Butt Weld / Threaded
Temperature Range
-46°C to 450°C (Depends on Material)
Product Images
Frequently Ask Questions
A Ball Type Double Block and Bleed (DBB) Valve is a valve arrangement that provides two separate isolation barriers and an intermediate bleed/vent point.
This allows the upstream and downstream sections to be isolated while pressure trapped between the two barriers can be released.
Bleeding the cavity between the two isolation barriers helps remove trapped process pressure and can provide an additional indication that the isolation barriers are functioning as intended.
Double isolation refers to providing two isolation barriers.
DBB adds a dedicated bleed/vent point between those barriers, allowing the intermediate cavity to be depressurized or monitored.
The basic sequence is:
Upstream ball closes.
Downstream ball closes.
The intermediate cavity is isolated from the process.
The bleed/vent is opened.
Trapped pressure is released.
The bleed point can be monitored to verify isolation.
For applications requiring double isolation and pressure verification, a DBB arrangement can provide a higher level of isolation assurance than relying on a single isolation valve.
However, the appropriate isolation philosophy should always follow the project's safety requirements and applicable standards.
Alis Valves is a Ball Type Double Block and Bleed Valve manufacturer and supplier in India, offering DBB valve solutions for oil & gas, petrochemical, refinery, chemical, hydrocarbon and high-pressure process applications. The valves are available with floating or trunnion-mounted balls, multiple seat materials and manual or automated operation options.
