DBB – Double Block & Bleed Valve System – Pyramid Technical Services

Double Block & Bleed Valves (DBB Series)

High Precision Isolation & Safe Venting for Sampling and Chemical Injection

The Double Block and Bleed (DBB) Valve Series is designed to provide positive isolation and controlled venting in high-pressure pipelines and process vessels. Combining two independent isolation valves with a central bleed/vent valve, this assembly ensures safe, complete isolation between the process fluid and downstream instrumentation or sampling equipment.

Compact, modular, and engineered for severe service, the DBB valve is ideal for chemical injection, sampling points, instrumentation, and any other application that requires positive and dual-barrier isolation.

The DBB assembly integrates:

Two Independent Block Valves
High-integrity ball valves providing primary and secondary isolation.
Central Bleed/Vent Valve
Heavy-duty needle valve for depressurization, venting, or safe sampling.
Modular or One-Piece Body Designs
Available in bolted modular form or a compact, forged one-piece body for reduced leak paths.
Multiple Connection Types
- NPT threaded
- Raised Face (RF) flange
- Ring Joint (RJ) flange
- API flanged connections
- Sizes: ½” to 2″ standard
Injection & Sampling Ports
Dedicated connections for quills, nozzles, or sampling probes as required.

Functional Layout :

Upper Connection
Used for sampling probes, injection quills, transmitters, or instrumentation take-off points.
Bottom Connection
Used for main process line isolation or chemical injection inlet.
Central Bleed Valve
Used to vent trapped pressure between the two block valves before removal of downstream equipment.

Connection Standards :

Inlet/Outlet Options
- NPT female threaded (ANSI B1.20.1)
- RF flange (ANSI B16.5)
- RJ flange (API spec)
- API RJ flanges for high-pressure requirements
Vent/Bleed Ports
- ¼” NPT
- ½” NPT
- ¾” NPT
- 1″ NPT

Benefits :

High-integrity dual isolation improves safety for operators
Eliminates need for multiple valves and fittings
Reduces installation footprint and leak paths
Simplifies maintenance and improves system reliability
Fully compatible with intrusive corrosion monitoring equipment
Ensures controlled depressurization before equipment removal
Suitable for severe service, corrosive fluids, and high-pressure conditions

Key Features :

Double block isolation for maximum operator safety.
Integrated bleed/vent function for safe depressurization.
Compatible with chemical injection and fluid sampling devices.
Available in flanged or NPT threaded configurations.
Complies with ANSI B16.34 material thickness and design standards.
Fully tested to API 598 / API 6D.
Fire-safe design meeting API 607 / API 6FA.
Fugitive emission compliant per ISO 15848.
Sour service compatible to NACE MR0175 / ISO 15156.
Suitable for high-pressure service, including API flange classes.
Modular design enables easy maintenance and seal replacement.
Smooth operation with low torque requirement.

Applications :

Chemical Injection Points
Complete integration with injection quills, check valves, and shut-off valves
Safe Sampling
Safe, depressurized sampling from live process lines
Instrumentation Isolation
Manifolds, transmitters, and gauges requiring reliable dual-valve isolation
Pipeline & Vessel Isolation
High-pressure isolation where single-valve protection is not adequate

Design Variants :

The following DBB Valve types are available :

Modular Bolted Design
Flexible maintenance, replaceable modules,and suitable for multiple service conditions
One-Piece Forged Body
Optimized sealing integrity with minimal leak paths and compact footprint
Integral Check Valve Designs
Built-in non-return valve for chemical injection applications, thereby preventing backflow
Ball Bleed Valve Variants
For applications requiring fast bleed-off and minimal pressure drop

All variants support the same connection standards and isolation principles.

Accessories (Sampling & Injection) :

The DBB valve supports a complete range of accessories:

Injection quills and nozzles
Chemical injection check valves
Shut-off valves and nipples
Sampling probes
Blanking plugs
Seal/repair kits (packing, O-rings, gaskets)

These accessories allow full integration into chemical dosing or sampling programs without additional fittings
or tees.

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