Large Caliber Hydraulic Double Eccentric Double Flange Butterfly Valve Overview
The large caliber hydraulic double eccentric double flange butterfly valve is an isolation and flow-control valve engineered for high-flow water supply, hydropower, municipal distribution and industrial pipeline headers where nominal sizes exceed standard wafer patterns and stable double-flange retention is required. Manufactured by Trekre & Fouten Valve, this double eccentric butterfly valve combines a offset disc geometry with multi-layer metal hard sealing or resilient seat options, double-flange end connections on both sides, and actuator choices including hydraulic cylinder packages, worm gear handwheel, electric motor or pneumatic actuator. The double-flange body carries independent bolt sets upstream and downstream, making it suitable for large-bore trunk mains, pump station isolation, reservoir outlet lines and hydropower penstock branches where pipeline loads and dead-end thrust must not transfer through a clamped wafer body.
Construction and design features
- Connection type: double flange (RF or FF per ANSI, DIN, JIS or GB; bolted to pipeline flanges on both ends)
- Structure: double eccentric (double offset) disc with stem axis offset from disc center and seat centerline
- Size range: DN300 to DN3600 (12″ to 144″) for large caliber hydraulic service; confirm face-to-face per GB/T 12238, API 609 or project drawing
- Pressure rating: PN10, PN16, PN25 and PN40; Class 150 and Class 300 on ANSI flange pairs (size and material dependent)
- Body material: carbon steel WCB, stainless steel CF8/CF8M, duplex steel or ductile iron selected for medium and external environment
- Seat and seal: multi-layer metal hard seal, resilient EPDM/NBR or metal-to-metal with STL overlay per service temperature
- Actuation: hydraulic cylinder with manual override, worm gear reduction, electric actuator or pneumatic actuator with ISO 5211 mounting pad
- Temperature range: -29°C to 650°C depending on seat material, body alloy and continuous exposure conditions
- Standards: GB/T 12238, API 609 Category B, MSS SP-67, ASME B16.34, ASME B16.5 flange dimensions
Double eccentric disc geometry and sealing performance
Double eccentric butterfly valves position the stem axis behind the disc center plane and offset from the seat centerline. During the opening stroke the disc lifts away from the seat before rotation, reducing friction and wear compared with concentric designs. Near the closed position the disc engages the seat with a cam-like motion that compresses the seal ring without unnecessary sliding contact across the full 90-degree travel. This geometry delivers lower operating torque at large nominal sizes, extended seat life in frequent cycling service and reliable shut-off performance documented per project leakage criteria in the factory test report.
The sealing system can be configured as multi-layer metal hard seal with flexible graphite or PTFE interlayers for high-temperature steam and process gas, or as resilient bonded seat for potable water and raw water where bubble-tight closure at low differential pressure is the primary requirement. Trekre & Fouten Valve selects seat hardware, disc overlay and gasket materials based on the confirmed medium, design temperature and required leakage class rather than applying a single seal configuration across all large-bore sizes.
Double flange connection for large bore pipeline integration
Large caliber trunk mains and hydropower penstocks impose significant flange bolt loads, bending moments and axial thrust that wafer-type butterfly valves cannot safely carry without additional pipeline support. The double-flange body on this hydraulic double eccentric butterfly valve includes independent bolt holes on the upstream and downstream faces, allowing the valve to remain in the line when one flange is removed for pump or strainer maintenance. Face-to-face dimensions are confirmed against the specified flange standard before shipment from our Wuxi manufacturing facility.
Install the valve with the disc slightly open during flange bolt-up to protect seat edges and gasket lands. Use gaskets compatible with the service — rubber bonded for water, spiral wound for steam or high-temperature process fluids, or PTFE envelope for corrosive condensate. Tighten flange bolts in a star pattern to equalize gasket compression. For vertical installations on reservoir outlets or tower risers, confirm stem orientation and actuator weight support with the project structural engineer.
Hydraulic actuation for large bore operation
Manual handwheel operation becomes impractical above DN600 on metal-seated double flange butterfly valves where breakaway torque at rated differential pressure can exceed several thousand newton-metres. Hydraulic cylinder actuation converts fluid pressure from a dedicated power unit or plant hydraulic header into the linear force needed to rotate the disc through a scotch-yoke, rack-and-pinion or lever mechanism mounted on the valve stem extension. Hydraulic packages suit dam outlet gates, hydropower plant isolation, flood-control pump headers and remote trunk main valves where electric power is limited but a central hydraulic station is available.
Each hydraulic actuator is sized for the valve nominal size, rated differential pressure, required opening and closing time, and safety factor for aged gaskets and sediment buildup on the seat line. Manual hydraulic pump override, accumulator emergency close and position feedback switches can be integrated per project specification. Where hydraulic infrastructure is not present, worm gear handwheel, electric multi-turn actuator or pneumatic rack-and-pinion actuator alternatives mount on the same ISO 5211 top flange without body modification.
Multi-layer metal hard seal for high temperature service
Large caliber double eccentric butterfly valves in metallurgy, petrochemical and hydropower applications frequently handle steam, hot process water, compressed air and mixed gas streams above the temperature limit of standard resilient seats. The multi-layer metal hard seal configuration stacks flexible graphite, PTFE or stainless foil layers between rigid metal seat components, maintaining contact pressure across thermal cycles while accommodating minor seat distortion at flange bolt-up. Fire-safe design options with secondary metal seat backup are available where project specifications reference API 607 or equivalent fire test requirements.
Hard-sealed large bore butterfly valves are intended primarily for on-off isolation. Throttling beyond the partial-open limits defined on the data sheet can cause cavitation, erosion and accelerated seat wear at high velocity across the disc edge. Confirm flow direction marking on the body and install with the preferred pressure side per the submittal drawing.
Typical applications and industry sectors
Water conservancy and municipal agencies deploy large caliber hydraulic double eccentric double flange butterfly valves on raw water intake lines, treated water trunk mains, reservoir outlet isolation and pump station suction and discharge headers where DN600 and above sizes require double-flange retention and hydraulic or gear-assisted operation. Hydropower stations use these valves on penstock branches, spiral case inlets, draft tube isolation and cooling water circulation where rapid closure under emergency conditions may be specified.
Metallurgical plants specify double eccentric metal-sealed double flange butterfly valves on blast furnace gas mains, converter off-gas headers and high-temperature process water lines up to 650°C with appropriate body and seat alloys. Petrochemical and power generation facilities install large bore butterfly valves on cooling water headers, fire water mains and general utility isolation where space savings relative to gate valves and shorter face-to-face dimensions simplify plant layout. Air separation, gas transmission and district energy networks also use double-flange double eccentric patterns when pipeline diameter and operating pressure demand a compact rotary isolation valve with proven API 609 construction.
Installation, commissioning and maintenance
After installation, cycle the valve fully open and closed under no-flow conditions to verify smooth actuator operation, correct disc orientation and limit switch or position indicator function if fitted. Introduce process fluid gradually and inspect flange joints, stem packing and hydraulic line connections for leakage. For hydraulic actuators, confirm power unit pressure, accumulator pre-charge and manual override operation before placing the valve in automatic service.
Periodic maintenance includes actuator lubrication per site procedure, stem packing adjustment, hydraulic fluid filter replacement and visual inspection of external coatings in outdoor installations. Inspect seat contact and disc edge condition during scheduled shutdowns; large bore butterfly valves in sediment-laden raw water service may require periodic seat cleaning to maintain shut-off performance per the test report criteria. Store spare valves with the disc in the slightly open position to avoid permanent seat compression during extended warehouse periods.
Selection and ordering information
When specifying this large caliber hydraulic double eccentric double flange butterfly valve, provide medium name, design temperature and pressure, nominal size, flange standard and facing type, body and seat material preferences, actuator type (hydraulic, worm gear, electric or pneumatic), required opening and closing time, leakage class and any extension stem, buried service or position feedback requirements. Confirm whether the installation requires dead-end service rating on one flange side and whether the valve must meet API 609 Category B or project-specific hydrostatic test pressures. Trekre & Fouten Valve factory tests each large bore butterfly valve for seat leakage, actuator function and flange dimensional compliance prior to shipment.
Product parameters summary
- Valve type: large caliber hydraulic double eccentric double flange butterfly valve
- End connection: double flange (RF/FF per standard)
- Structure: double eccentric (double offset) disc
- Body: WCB, CF8/CF8M, duplex steel or ductile iron
- Seat: multi-layer metal hard seal or resilient EPDM/NBR
- Actuator: hydraulic cylinder, worm gear, electric or pneumatic
- Size: DN300–DN3600 (12″–144″)
- Pressure: PN10 / PN16 / PN25 / PN40; Class 150 / Class 300
- Temperature: -29°C to +650°C (seat and body dependent)
- Applicable media: water, steam, air, gas, slurry and industrial process fluids
- Manufacturing: Trekre & Fouten Valve, Wuxi, China