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China Suppliers Factory Flanged NPT/BSP Lockable 2500LB Reduced Bore DBB Double Ball Valve for Safe Isolation
True Double Block & Bleed Isolation
Two independent ball valves with a central bleed cavity provide positive upstream and downstream isolation with safe pressure release and verification.
Fixed Trunnion-Mounted Ball Design
Trunnion-mounted structure reduces operating torque and ensures stable sealing performance under high pressure conditions.
Asymmetric Flanged × Threaded Configuration
Flanged inlet combined with high-pressure threaded outlet enables compact and flexible installation in complex pipeline layouts.
Optimized for Sampling & Instrument Applications
Reduced bore design is ideal for sampling points, injection lines, and instrumentation branches without compromising isolation safety.
Dual Independent Lockable Stems
Independent stem bases with locking devices prevent accidental or unauthorized operation in hazardous environments.
Forged Steel Construction for Severe Service
Forged body materials with Class 2500 pressure rating ensure long-term reliability in Oil & Gas, offshore, and high-pressure chemical services.
What is the function of the central bleed cavity in a Double Block & Bleed valve?
The central bleed cavity sits between the two independent ball valves and allows operators to safely vent or verify that pressure has been fully released between the upstream and downstream isolation points. This ensures there is no trapped pressure before maintenance or inspection work begins.
Why is a trunnion-mounted ball design preferred over a floating ball design at high pressure?
In a trunnion-mounted design, the ball is mechanically anchored at the top and bottom, preventing it from shifting under high pipeline pressure. This significantly reduces the operating torque required to turn the valve and maintains consistent, reliable sealing even in high-pressure or high-temperature service conditions.
What are the advantages of an asymmetric flanged × threaded end configuration?
The combination of a flanged inlet with a high-pressure threaded outlet gives engineers flexibility when integrating the valve into complex piping systems. The flanged side provides a secure, gasket-sealed connection for the main line, while the threaded outlet allows for compact, space-saving connections to instruments or sample points.
Is this valve suitable for use in sampling and instrumentation applications?
Yes. The reduced bore design minimizes dead volume, making it especially well-suited for sampling points, chemical injection lines, and instrumentation branches. It maintains full double block and bleed isolation safety regardless of the smaller bore size, ensuring accurate sampling results and safe operation.
How do the dual lockable stems improve operational safety?
Each of the two ball valves has an independent stem with a dedicated locking device. This prevents unauthorized or accidental actuation of either valve, which is critical in hazardous or classified environments such as offshore platforms, refineries, and chemical processing plants where unintended valve movement could lead to serious safety incidents.
What pressure rating and material standards does this valve meet for Oil & Gas service?
The valve is constructed from forged steel to achieve a Class 2500 pressure rating, which corresponds to extremely high-pressure service requirements. This forged construction meets the demands of upstream Oil & Gas production, offshore subsea systems, and high-pressure chemical processing, providing long service life and resistance to fatigue, corrosion, and thermal cycling.