Description

Product Brief Introduction

The EMT double block and bleed valve isolates pressure from both pipeline sides in one API 6D body and reads pig passage live. It vents the cavity for safe maintenance. ASME U-Stamp and NACE MR0175 compliant.

A legacy isolation stack needs three valves and a bleed point, so a tie-in takes space and adds leak paths. A refinery turnaround waits for verified zero-energy isolation.

Q: How do I isolate a pipeline safely without three valves?
A: A double block and bleed valve blocks upstream and downstream in one body, then vents the cavity between the seats. EMT’s design also reads pig passage live, so you verify isolation and track pigs without extra valves.

Technical Parameters

EMT builds every DBB valve to API 6D with full material traceability. Custom sizes and classes are available on request.

Parameter	Value
Product Type	DBB pipeline isolation valve with integrated pig signaller
Size Range	2″–24″ (DN50–DN600)
Pressure Class	Class 150–2500 (PN20–PN420)
Temperature	-46°C to +200°C (-50°F to +392°F)
Body Material	A105, A350 LF2, F304 / F316 (NACE MR0175 option)
Connection	RF / RTJ flange, butt-weld
Sealing	Double block and bleed, bidirectional
Flange Standard	ASME B16.5 (DIN / JIS / GB on request)
Pig Signaller	Magnetic / mechanical, live local indicator
Design Standards	API 6D, ASME B16.34
Sour Service	NACE MR0175 / ISO 15156 compliant
Certification	ASME U-Stamp, API 6D, NACE MR0175

Product Advantages

• One-Body Isolation — Two seats block pressure both directions at once, so you isolate faster than a three-valve stack.
• Live Pig Signaller — A magnetic or mechanical indicator reads pig passage without breaking containment or stopping flow.
• Ventable Cavity — The bleed port vents trapped fluid, which confirms a safe zero-energy state before entry.
• Online Service — You remove the detector core under full pressure, avoiding costly shutdowns.
• ASME U-Stamp Body — Pressure-retaining parts are built, hydrotested, and stamped in EMT’s own shop.

Where Is a Double Block and Bleed Valve Used?

• Transmission pipelines — Isolate and bleed at tie-ins on oil and gas trunk lines.
• Refinery turnarounds — Verify zero-energy isolation before opening the line for maintenance.
• Wellhead manifolds — Hold pressure on sour-gas gathering systems with NACE material.
• Tank-farm transfer — Block both sides on product transfer lines without shutdown.
• Pig stations — Combine isolation with live pig detection at launch and receive sites.
• LNG terminals — Low-temperature grades serve LNG and LPG duty to -46°C.

About EMT

EMT Pipe is a Shenyang-based manufacturer of oil and gas pipeline integrity equipment, serving 30+ countries since the 1990s.

Capabilities:
– In-house forging, CNC machining, and hydrostatic testing to 69 MPa (10,000 psi)
– ASME Section IX qualified welding and NDT: UT, PT, RT, MT
– 25+ years of valve and closure engineering
– Integrated pig-signaller assembly in one workshop

Certifications: ASME U-Stamp, API 6D, NACE MR0175 / ISO 15156, ISO 9001.

Service: English, Arabic, Spanish, and Chinese support; standard valves ship in 4–6 weeks, custom in 6–10 weeks.

Frequently Asked Questions

Q: What is the difference between double block and bleed and double isolation and bleed?

A: A double block and bleed (DBB) valve uses two seats to block both flow directions; a double isolation and bleed (DIB) valve adds a second independent seal on each seat. Choose DIB for critical double-seal duty; DBB covers most isolation and pig-tracking jobs.

Q: Can the DBB valve be serviced without shutting down the pipeline?

A: Yes. The integrated pig signaller core is removable under full pipeline pressure. You vent the cavity through the bleed port, then unbolt the core. Flow continues, which avoids shutdown cost.

Q: Does your DBB valve suit sour service?

A: Yes. Wetted parts use NACE MR0175 / ISO 15156 compliant material for H2S and CO2. Low-temperature grades serve LNG and LPG duty. EMT reviews each order for material compatibility.

Q: What standards and certifications does the valve meet?

A: Design follows API 6D and ASME B16.34; flanges follow ASME B16.5. Pressure-retaining parts carry ASME U-Stamp and meet NACE MR0175. Each unit is hydrotested and ships with test reports.

Q: What size range do you offer for a double block and bleed valve?

A: EMT builds DBB valves from 2″ to 24″ (DN50–DN600) in Class 150–2500. Connections include RF, RTJ flange, and butt-weld. We confirm final size and class against your line data.

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• Chemical Injection Quill(/chemical-injection-quill)
• API 6D Pipeline Valves