Double-Flanged Metal-Seated Butterfly Valve

The Double-Flanged Metal-Seated Butterfly Valve incorporates a triple-offset non-rubbing geometry and a solid metal-to-metal seating system, delivering zero-leakage bi-directional shutoff under high-temperature, high-pressure, and severe thermal cycling conditions across critical energy and fluid piping networks.

Triple-Offset Geometry: Frictionless rotation between seal ring and body seat minimizes wear and operational torque.

Bi-Directional Zero Leakage: Tight metal shutoff compliant with API 598 and ISO 5208 Rate A under full pressure differential in both flow directions.

Fire-Safe All-Metal Structure: Maintains seal integrity during and after fire exposure without relying on soft inserts.

Double-Flanged Body Rigidity: Independent bolting to pipe flanges prevents piping stress from binding internal components.

Blowout-Proof Stem Design: Internal stem retention collar built to API 609 requirements prevents stem ejection under operational pressure.

Stellite Hard-Faced Seat: Plasma arc welding overlay protects seating surfaces against particle abrasion, erosion, and cavitation.
 

Primary Offset: Shaft position located behind the seal ring plane enables continuous 360-degree sealing contact.

Secondary Offset: Shaft centerline offset laterally from the pipe centerline lifts the disc off the seat instantly upon rotation.

Tertiary Offset: Inclined conical sealing axis creates a cam action, restricting seal contact solely to the final closure point.

Laminated Metal Disc Seal: Dynamic alternating layers of stainless steel and expanded graphite absorb thermal expansion without binding.

Heavy-Duty Bushings: Hardened stainless steel bushings impregnated with graphite reduce shaft friction and prevent galling.

The valve operates via a 90-degree rotational shaft sequence. Upon closure, the third offset geometry translates rotational torque into axial seating compression. The flexible laminated metal disc ring wedges uniformly into the conical body seat, establishing a mechanical seal that holds full line pressure in both normal and reverse flow conditions.

Double-Flanged Design: Full-thickness flanges with through-bolt holes match line flanges, supporting dead-end service without downstream flange pressure.

Raised Face (RF): Standard serrated finish (Ra 3.2 to 6.3 micrometers) for spiral wound gaskets.

Ring Type Joint (RTJ): Precision metallic ring groove for high-pressure ASME Class 600 and Class 900 installations.

Flat Face (FF): Machined smooth face for cast iron piping and low-pressure municipal connections.

Manual Worm Gearbox: Fully enclosed weather-proof gear unit with mechanical position indicator and handwheel locking device.

Pneumatic Actuator: Double-acting or spring-return scotch-yoke configuration equipped with limit switches, solenoid valve, and air filter regulator.

Electric Actuator: On-off or modulating electric motor drive supporting Fieldbus, HART, and Modbus control protocols.

Hydraulic Actuator: High-torque hydraulic cylinder drive for rapid emergency shutdown applications.

Actuator Mounting: ISO 5211 direct-mount top flange layout for field installation.

Refining & Petrochemical: Hydrocracking units, catalytic reformers, hot gas lines, and crude oil manifold distribution.

Power Generation: Main steam isolation, high-pressure feedwater systems, and turbine extraction piping.

LNG & Cryogenics: Liquefied natural gas receiving terminals, boil-off gas handling, and cryogenic storage systems.

Chemical Processing: Corrosive acid gas lines, high-temperature thermal fluid circuits, and solvent recovery plants.

District Energy: High-pressure steam heating networks and centralized hot water main pipelines.

Operating Pressure & Temperature: Match system maximum operating limits to the ASME pressure class and material thermal boundaries.

Body & Trim Metallurgy: Select carbon steel for non-corrosive steam/oil up to 400°C; select stainless steel or duplex alloy for chloride-bearing or corrosive media.

Sealing Ring Configuration: Specify metal-graphite laminated seal rings for service below 450°C; specify solid metal-to-metal seating for abrasive media or temperatures exceeding 450°C.

Actuator Torque Margin: Calculate required breakout torque incorporating a minimum 25 percent safety factor above dynamic differential pressure requirements.

Certification Requirements: Confirm required test certificates, including API 607 fire-test, ISO 15848-1 emission testing, or NACE MR0175 compliance.

Pressure Testing: Hydrostatic shell test at 1.5 times nominal pressure and gas seat leakage test at 1.1 times nominal pressure per API 598.

Positive Material Identification (PMI): Handheld XRF elemental analysis performed on all pressure-retaining castings, forgings, and shafts.

Non-Destructive Testing (NDT): Radiographic examination (RT) on casting radiographs, Ultrasonic testing (UT) on forged stems, and Liquid Penetrant testing (PT) on Stellite hard-faced seats.

Dimensional Inspection: Coordinate measuring machine (CMM) verification for flange hole alignment, stem concentricity, and face-to-face dimensions.

Fugitive Emission Testing: Helium mass spectrometer leakage measurement to verify stem packing tightness during mechanical cycling.

Special Material Alloys: Cast and forged bodies in Titanium, Monel, Inconel, Hastelloy, and Super Duplex stainless steel.

Cryogenic Neck Extension: Extended bonnet configurations for cryogenic insulation barriers in LNG service.

Steam Jacketing: Welded heating jackets surrounding the body to prevent viscosity loss or fluid crystallization.

Custom Face-to-Face: Tailored laying lengths manufactured to replace legacy gate or globe valves without modifying existing pipe runs.

Paint Systems: Multi-coat epoxy, polyurethane, and zinc-rich primer coating systems tailored to offshore marine environments.