Carbon Steel Flanged Trunnion Ball Valve

The Carbon Steel Flanged Trunnion Ball Valve is engineered for high-pressure, large-diameter, and critical isolation services in oil & gas transmission, petrochemical processing, LNG terminals, and power generation systems.
Unlike floating ball valves, the trunnion-mounted design supports the ball on both upper and lower bearings, significantly reducing operating torque while ensuring stable, bi-directional sealing performance under high differential pressure conditions.
This design is widely selected in global EPC projects and long-distance pipeline systems, where reliability, safety, and lifecycle cost optimization are critical.

Why Trunnion Ball Valve for High-Pressure Service?

Engineering Principle
In floating ball valves, line pressure forces the ball against the downstream seat, leading to:

High operating torque in large sizes
Accelerated seat wear under pressure
Unstable sealing in high differential pressure conditions

Trunnion Solution
The trunnion design resolves these issues through mechanical load distribution:

Ball is fixed by upper and lower trunnions
Line pressure is transferred to bearings instead of seats
Spring-loaded seats ensure continuous sealing contact

Engineering Outcome

40–70% lower operating torque vs floating ball valves
Smaller actuator requirement → reduced automation cost
Stable sealing under Class 150–2500 pressure range
Extended service life in continuous operation pipelines

Key Technical Advantages

01/

Heavy-Duty Carbon Steel Construction (WCB / A105 / LCB / LCC)
Manufactured from ASTM A216 WCB cast steel or forged A105 steel:

High mechanical strength and pressure resistance
Excellent weldability for pipeline integration
Stable thermal cycling performance
Optional low-temperature and cryogenic materials for LNG service

02/

Double Block and Bleed (DBB) Function
Designed for critical isolation systems:

Upstream and downstream seats seal independently
Body cavity can be vented via bleed valve
Enables safe verification of sealing integrity

Engineering benefit:
Supports maintenance safety without line disassembly.

03/

Cavity Pressure Self-Relief Design
When cavity pressure exceeds spring preload:

Seat automatically relieves excess pressure
Prevents over-pressurization of valve body
Enhances operational safety in thermal expansion conditions

04/

Flanged End Connection

ASME B16.5 (≤24") / B16.47 (≥26")
RF or RTJ flange options
Bolt-up installation (no welding required during maintenance)
Reduced shutdown time in EPC turnaround projects

Sealing System Options

Soft Seated (Bubble-Tight Service)

PTFE / RPTFE / Nylon / Devlon

Low leakage performance (ISO 5208 Rate A)
Suitable for gas, water, and general hydrocarbons

Metal Seated (Severe Service)

Stellite / Tungsten Carbide (HVOF) / Chromium Carbide

Resistant to erosion and high temperature
Suitable for slurry, abrasive, and high-temperature media

Fire-Safe & Anti-Static Design

API 607 / API 6FA fire-tested
Secondary metal sealing under fire conditions
Anti-static grounding between stem, ball, and body

Blowout-Proof Stem Design

Integrated T-type stem shoulder
Prevents stem ejection under internal pressure
Suitable for high-pressure and hazardous systems

Typical EPC Applications

This valve is widely used in:

Oil & Gas Transmission Pipelines
Refineries & Petrochemical Plants
LNG Liquefaction & Regasification Terminals
Power Plants (Steam & Cooling Systems)
Offshore Platforms & Subsea Manifolds

Engineering Problems Solved

Engineering Challenge	Trunnion Valve Solution
High actuator cost	Low torque reduces actuator size
Seat wear in high pressure	Spring-loaded independent seats
Frequent shutdown maintenance	Reduced friction and longer service life
EPC approval complexity	API 6D / ASME compliant design
Automation instability	Predictable torque curve for ESD systems

Quality Assurance & Factory Testing

Each valve is 100% tested before shipment:
Shell hydrostatic test (API 6D / ASME B16.34)
High-pressure seat leakage test
Low-pressure air test
Operating torque verification
NDT inspection (RT / UT / PT / MT as required)

Documentation Package
EN 10204 3.1 Material Certificate
Hydrostatic & pneumatic test reports
Full material traceability records
API 6D / CE / PED compliance certificates

Technical Specifications

Parameter	Specification
Size Range	2" – 48" (DN50 – DN1200)
Pressure Rating	Class 150 – 2500 (PN16 – PN420)
Body Material	A216 WCB, A105, LCB, LCC, WC6, WC9
Ball & Stem	SS304 / SS316 / F51 / F53 / ENP coated
Seat Materials	PTFE / RPTFE / Metal seated (Stellite / TCC)
End Connection	RF / RTJ Flanged (ASME B16.5 / B16.47)
Design Standards	API 6D / ASME B16.34 / ISO 17292
Fire Safety	API 607 / API 6FA
Operation	Manual / Gear / Pneumatic / Electric / Hydraulic
Certification	ISO 9001 / CE / PED / SIL 3 capable

Project Supply Capability

We support global EPC contractors, distributors, and industrial stockists with:

Large-scale production capacity for project packages
OEM/ODM customization (extended stem, coatings, bypass, special flanges)
Full submittal documentation (GA drawings, ITP, datasheets)
Export-ready seaworthy packaging with anti-corrosion protection

Typical Delivery Capability

Standard configuration: 3–5 weeks lead time
Project orders: Scheduled production planning available
Export packaging: Seaworthy wooden cases with moisture protection

Proven Application Experience

Our trunnion ball valves have been supplied to:

LNG terminal projects in Middle East & Asia

Refinery expansion projects in Southeast Asia

Cross-country pipeline systems in Europe and Africa

Offshore platform isolation systems

Frequently Asked Questions

Q: Why choose trunnion ball valves over floating types?

A: Trunnion design significantly reduces torque by mechanically supporting the ball, making it ideal for high-pressure and large-diameter pipelines where floating valves become inefficient and high-maintenance.

Q: Can these valves be used in automated systems?

A: Yes. With ISO 5211 mounting pads and low torque design, they are fully compatible with pneumatic, electric, and hydraulic actuators for ESD and remote control systems.

Q: Are these valves suitable for severe service?

A: Yes. Metal-seated configurations with Stellite or carbide coatings are designed for abrasive, high-temperature, and high-pressure applications.

Q: What certifications are available?

A: API 6D, API 607, CE/PED, ISO 9001, and SIL 3 capability depending on configuration.

Q: How do you ensure international shipping reliability?

A: All valves are:
Fully corrosion-protected
Vacuum sealed and moisture-controlled
Crated in export-grade seaworthy packaging
Accompanied by full inspection and certification dossiers

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