Double Block & Bleed Valves

Product Overview

The Alphex Engineers Double Block & Bleed (DBB) valve range represents the pinnacle of isolation technology. By integrating two isolation points and a bleed function into a single valve body, Alphex Engineers provides a solution that replaces traditional multi-valve manifolds. This significantly reduces weight, space requirements, and potential leak paths, providing maximum safety during downstream maintenance in critical Oil & Gas applications.

DBB & DIB Design Configurations :

Alphex Engineers manufactures DBB valves in multiple specialized configurations to meet API 6D requirements:

• DBB Type A : Features two independent isolation valves (balls) with a bleed valve in between.
• DBB Type B : A single ball valve with two independent seating surfaces and a central bleed port.
• DIB-1 (Double Isolation & Bleed) : Equipped with two Double Piston Effect (DPE) seats, providing bi-directional sealing from both sides.
• DIB-2 : Equipped with one DPE seat and one Self-Relieving (SR) seat, allowing for internal cavity pressure management.

Design & Construction Features

Engineered for zero-compromise safety, the Alphex Engineers DBB range includes:

• Construction : One, Two, or Three-piece forged or cast bodies.
• Entry : Side Entry or Top Entry designs for process flexibility.
• Isolation Integrity : Double Isolation Function with integrated Cavity Vent and Drain ports.
• Sealing : Bubble-tight shut-off in both liquid and gas services.
• Advanced Metallurgy : Optional CRA (Corrosion Resistant Alloy) Overlay in Inconel or Stainless Steel for wetted parts.
• Wear Resistance : Tungsten Carbide or Chrome Carbide coatings for high-cycle and abrasive applications.
• Compliance : Full adherence to NACE MR0175, API 6D, and ISO 5211 for actuator mounting.

Material of Construction (MOC)

Alphex Engineers ensures the highest material integrity for DBB units :

• Body/Bonnet : Carbon Steel (A105/LF2), Stainless Steel (F316/CF8M), Duplex (F51), and Super Duplex (F53/F55).
• Trim : High-strength alloys with optional Hard Facing (Stellite or Tungsten Carbide).
• Seats : Soft inserts (Devlon/PEEK/PTFE/RPTFE) or Metal-to-Metal sealing for extreme conditions.

Operation & Range

• Operation : Lever, Gear, Pneumatic, or Electric Actuation.
• Size Range : ½” to 4” (Standard) and larger upon project request.
• Pressure Class : Up to ASME 2500#.