Flanged Butterfly Valve – Custom Valve by Leading Foundry

1. Panimula

A Flanged butterfly valve (FBV) is a quarter-turn valve widely recognized as the workhorse of high-pressure and permanent fluid control systems.

Characterized by their integral flanges that bolt directly to pipeline flanges, they provide a rigid, leak-proof, and structurally stable connection,

a critical advantage over wafer-style valves (space-saving but suited for low-pressure duties) and lug-style valves (moderate pressure, often for non-critical service).

Engineered for medium to large-diameter pipelines, flanged butterfly valves combine tight shutoff, structural reliability, at kadalian ng pagpapanatili.

Kasabay nito, their versatility makes them indispensable in paggamot ng tubig, HVAC networks, and general industrial processing, where their compact na disenyo, kahusayan sa gastos, and adaptability across pressure and temperature ranges deliver long-term operational value.

2. What is a Flanged Butterfly Valve?

Core Definition and Working Principle

A flanged butterfly valve (FBV) ay isang quarter-turn rotary balbula designed for regulating or isolating flow in pipelines.

Its defining feature is the integral flanges, which bolt directly to pipe flanges (per ANSI B16.5 or ISO 7005), creating a rigid, leak-tight, and permanent connection suitable for high-pressure service.

The valve operates on a simple principle:

• Ganap na Buksan (0°): The disc lies parallel to flow, minimizing pressure loss (typically 1–3 psi for a 6-inch valve at nominal flow).
• Throttling (10–80°): Partial rotation restricts flow; eccentric disc designs provide more linear flow control than concentric types.
• Ganap na Sarado (90°): The disc presses firmly against the seat, achieving tight shutoff. FBVs are bidirectional, handling forward and reverse flows effectively.

Anatomy of a Flanged Butterfly Valve

A flanged butterfly valve is engineered for durability and precision control, typically comprising six core components:

Flanged vs. Wafer vs. Lug Butterfly Valves

Ang integral flange design sets FBVs apart from wafer and lug types, offering unique advantages for high-demand applications:

3. Design Variations: Concentric vs. Eccentric Flanged Butterfly Valves

Flanged butterfly valves are classified primarily by disc and stem alignment, a critical factor influencing pressure rating, Pagganap ng pagbubuklod, torque requirements, at angkop na aplikasyon.

Concentric Flanged Butterfly Valves (Standard Design)

Geometry: The disc and stem axes align with the valve’s bore center, making the design concentric. During operation, the seat maintains contact across the entire disc surface.

Mga Sukatan ng Pagganap:

• Rating ng Presyon: ANSI Class 150–300 (28–70 bar at 20°C)
• Leakage Class: API 609 Class IV (≤0.01% of nominal flow for liquids)
• Torque Requirement: 60–100 N·m (6-inch valve, EPDM seat)
• Cycle Life: 10,000–20,000 cycles (resilient seat limits lifespan)

Mga kalamangan:

• Simple lang, cost-effective design
• Easy maintenance and seat replacement
• Suitable for moderate temperature and pressure fluids

Mga Limitasyon:

• High disc-seat friction reduces efficiency
• Not suitable for gas service or high-pressure applications
• Limited durability under abrasive or high-temperature fluids

Mga Karaniwang Aplikasyon:

• HVAC chilled water systems
• Municipal water distribution
• Low-pressure, non-critical industrial services

Eccentric Flanged Butterfly Valves (High-Performance Design)

Pangkalahatang ideya: Eccentric designs offset the disc or stem, reducing disc-to-seat friction and enhancing sealing performance.

These designs are ideal for mataas na presyon, mataas na temperatura, and gas applications.

Single Eccentric (Offset Disc) Flanged Butterfly Valve

Disenyo: The disc center is offset from the stem axis, which minimizes contact with the seat during rotation, pagbabawas ng alitan.

Mga Sukatan ng Pagganap:

• Rating ng Presyon: ANSI Class 300–600 (70–140 bar)
• Leakage Class: API 609 Class V (≤0.001% of nominal flow)
• Torque Requirement: 40–70 N·m (6-inch valve, PTFE seat)—~30% lower than concentric valves

Mga Aplikasyon:

• Industrial water treatment
• Low-pressure oil lines
• Applications requiring moderate flow control with improved efficiency

Double Eccentric (Offset Disc + halamang singaw sa paa) Flanged Butterfly Valve

Disenyo: Both the disc center and stem axis are offset from the bore center. This eliminates disc-seat contact until 80–85% of closure, significantly reducing friction and wear.

Mga Sukatan ng Pagganap:

• Rating ng Presyon: Klase ng ANSI 600 (140 bar at 20°C); up to Class 900 with metal seats
• Leakage Class: API 609 Class VI (≤0.00001% of nominal flow) — suitable for gas service, including natural gas pipelines
• Saklaw ng Temperatura: -29°C to 482°C (metal seats)

Mga Aplikasyon:

• Pagproseso ng kemikal
• Langis & gas pipelines
• Steam systems
• High-pressure industrial fluids requiring tight shutoff

Triple Eccentric (Offset + Tapered Disc) Flanged Butterfly Valve

Disenyo: Adds a third offset by introducing a conical/tapered disc geometry, achieving a metal-to-metal seal without the need for an elastic seat.

This design enables operation under extreme temperatures and pressures.

Mga Sukatan ng Pagganap:

• Rating ng Presyon: Klase ng ANSI 900 (210 bar at 20°C)
• Saklaw ng Temperatura: -29°C sa 650°C (Stellite® or hard metal seats)
• Cycle Life: 50,000–100,000 cycles (metal seat durability)

Mga Aplikasyon:

• Hypersonic vehicle cooling systems
• Power plant superheated steam lines
• Refinery catalytic crackers and petrochemical processing
• Extreme industrial environments requiring zero-leakage and long life

Buod:

4. Mga Materyal & Seals of Flanged Butterfly Valve

The performance, pagiging maaasahan, and longevity of double flanged butterfly valves (FBVs) are strongly influenced by pagpili ng materyal for the body, disc, stem, and sealing elements.

Proper materials ensure compatibility with the fluid, paglaban sa kaagnasan, high-pressure handling, and suitability for temperature extremes.

Body Materials

The valve body is the primary pressure boundary and must withstand mekanikal na stress, panloob na presyon, and environmental corrosion. Common body materials include:

Disc Materials

The disc is directly exposed to flow and often handles abrasive, erosive, or corrosive fluids. Selection is based on mekanikal na lakas, paglaban sa kaagnasan, and sealing compatibility:

• 316 Hindi kinakalawang na asero: Widely used for general-purpose chemical, tubig, and steam applications.
• Hastelloy C276: Resistant to oxidizing and reducing chemicals; suitable for aggressive acids.
• Ductile Iron with PTFE Coating: Mababang alitan, corrosion-resistant option for water and mild chemicals.
• Stellite®-Clad Discs: High-temperature and high-wear applications, including superheated steam and petrochemicals.

Design Note: The disc may be concentric, eccentric, or triple-offset, with metal or resilient coating to improve sealing and reduce wear.

Stem Materials

The stem transmits torque from the actuator or handwheel to the disc and is exposed to mekanikal na stress, presyon, and fluid contact. Common materials:

Seat Materials and Seal Types

Ang seat forms the critical sealing interface with the disc, determining leakage class, torque requirement, at buhay ng serbisyo. Selection depends on fluid type, presyon, at temperatura.

Gaskets and Actuator Interfaces

• Flange Gaskets: Graphite, PTFE, or nitrile gaskets ensure leak-proof flange connections between the valve and pipeline.
• Actuator Seals: O-rings or PTFE bushings prevent fluid leakage along the stem while enabling smooth torque transfer.

5. Paggawa & Foundry Methods of Flanged Butterfly Valves

Ang produksyon ng flanged butterfly valves (FBVs) requires high precision, robust materials, and strict adherence to international standards such as API 609, ISO 5752, at ANSI B16.5.

Valves designed for high-pressure and high-performance applications—like oil & gas pipelines, mga halaman ng kemikal, and power generation—must exhibit katumpakan ng sukat, integridad ng istruktura, and leak-tight performance.

Casting Butterfly Valve Components

Casting is the primary method for shaping valve bodies and discs, allowing complex geometries and cost-effective production. For large valves (typically over 12 pulgada), buhangin paghahagis is widely used.

Sa prosesong ito, molten metal (1450–1550°C) is poured into resin-bonded sand molds.

Sand casting offers tolerances around ±0.5 mm, making it suitable for carbon steel or ductile iron valves used in municipal water or low-pressure industrial pipelines.

For small-to-medium valves (2–12 inches) requiring high dimensional precision and corrosion resistance, pamumuhunan paghahagis (lost wax method) is employed. Wax patterns are coated with ceramic shells, melted out, and replaced with molten metal.

This method achieves tight tolerances (±0.1 mm) and smooth surfaces, enabling precise features such as double eccentric disc hubs.
Investment casting is ideal for 316L stainless steel, Bilisan mo na, or other corrosion-resistant alloys.

Pagbubuo ng mga: High-Strength Components

Forging is the preferred method for critical, high-pressure components such as bodies, mga flanges, and stems, because it produces superior grain structure and higher tensile strength.

Heated metal (1100-1200 ° C) is shaped under hydraulic presses or dies, resulting in 20–30% stronger parts than equivalent castings.

Forged components are typically used in ANSI Class 600 or higher valves for oil & gas pipelines, mga planta ng kuryente, and other demanding industrial applications.

Forging methods include open-die forging for large custom parts, closed-die forging for medium-sized components with precise dimensions, and upset forging to reinforce critical junctions like disc hubs.

Machining: Precision Finishing

After casting or forging, CNC machining ensures high dimensional accuracy, tapos sa ibabaw, and proper alignment:

• Flange faces are milled to achieve flatness within 0.1 mm and bolt hole alignment per ANSI B16.5 standards, ensuring leak-free connections.
• Seat bores are honed or machined to Ra 1.6–3.2 μm to allow proper seat bonding and effective sealing.
• Discs and hubs, especially eccentric designs, are finished with 5-axis CNC milling to maintain flatness within 0.05 mm for tight shutoff.
• Stems and bearings are turned and milled with precision to guarantee smooth rotation and correct torque transfer.

Paggamot ng Heat: Mechanical and Corrosion Properties

Heat treatment improves strength, tigas na tigas, and corrosion resistance depending on the material used:

• Carbon bakal (WCB): Quenched at 850°C and tempered at 650°C to achieve tensile strength ≥485 MPa.
• 316L hindi kinakalawang na asero: Solution-annealed at 1050–1100°C followed by water quenching to restore corrosion resistance and homogenize microstructure.
• Duplex 2205: Solution-annealed at 1020–1080°C to achieve a balanced austenite/ferrite ratio (50:50), optimizing both strength and corrosion resistance.

Paggamot sa ibabaw: Mahabang buhay & Paglaban sa kaagnasan

Surface finishing ensures durability in harsh environments:

• Passivation for 316L stainless steel enhances the natural chromium oxide layer, improving corrosion resistance by up to 20%.
• Epoxy coatings of 100–150 μm protect carbon steel bodies in oil & gas pipelines from soil and atmospheric corrosion.
• Electropolishing is used in sanitary applications (pagkain, inumin, mga parmasyutiko) to achieve Ra ≤0.8 μm, eliminating microscopic crevices and bacterial dead zones.

Assembly & Pagtiyak ng Kalidad

After machining and surface treatment, valves undergo assembly and rigorous quality control:

• Seat and disc integration: Seats are bonded or pressed, and eccentric discs are carefully aligned for precise shutoff.
• Stem installation: Mga bearing, packing, and O-rings are fitted, and torque is verified.
• Hydrostatic or pneumatic testing: Confirms leak-tight performance under design pressure.
• Pagsusuri na hindi nakakasira (NDT): Methods such as X-ray, ultrasonic na, or dye penetrant inspections detect internal defects.
• Actuator calibration: Manwal, mga elektriko, niyumatik, or hydraulic actuators are tested for torque and stroke accuracy.

6. Pressure Ratings, Sizes & Mga Pamantayan

Flanged butterfly valves (FBVs) are designed for reliability across a wide range of pressures, mga sukat, and industrial standards.

Proper selection ensures safety, long-term performance, and compatibility with pipeline systems.

Pressure Ratings

Standard Sizes

Face-to-Face Dimensions: Usually conform to ISO 5752 Serye 10 or API 609 for easy interchangeability.

Key Standards & Mga Sertipikasyon

7. Actuation & Mga Sistema ng Kontrol

Flanged butterfly valves are quarter-turn devices requiring actuators capable of 90° rotation.

Actuator selection depends on valve size, torque requirement, fluid type, and control sophistication.

Common Actuator Types and Specifications

Key Accessories for Enhanced Control

• Positioners: Provide precise modulating control (±0.5% accuracy), crucial for applications like HVAC chilled water, chemical dosing, or industrial process lines.
• Torque Switches: Protect the disc and seat from over-torquing, preventing premature wear or damage.
• Limit Switches: Deliver open/closed position feedback to SCADA or DCS systems for remote monitoring and automated safety protocols.
• Solenoid Valves & Air Filters (for pneumatic actuators): Ensure rapid, reliable actuation while protecting internal actuator components from contaminants.

8. Flanged End Geometry & Interface

Ang flanged end design is the defining characteristic of butterfly flange valves, pagtiyak ng isang rigid, secure, and leak-tight connection to pipeline systems.

The geometry is standardized globally to allow full interchangeability across manufacturers.

Flange Standards & Compatibility

Flanged butterfly valves are machined to match pipeline flanges in mga sukat, bolt-hole patterns, and pressure ratings. The most common standards include:

Dimensional Geometry

The flanged end geometry typically includes:

• Raised Face (RF): Standard sealing surface, 2–6 mm raised area around the bore, ensures even gasket compression.
• Flat Face (FF): Used with cast iron pipelines to avoid overstressing flanges.
• Ring-Type Joint (RTJ): Machined grooves for metal gaskets, suited for high-pressure/high-temperature services (hanggang sa 210 bar, 650°C).

9. Industrial Applications of Flanged Butterfly Valves

Flanged butterfly valves are maraming nalalaman, high-performance quarter-turn valves widely used across industrial sectors due to their reliability, compact na disenyo, and adaptability to a broad range of pressures, mga temperatura, and fluids.

Paggamot ng Tubig at Wastewater

• Paglalapat: Flow isolation, chemical dosing, and backwashing systems.
• Mga kalamangan: Tight shutoff, low-pressure drop, corrosion-resistant seats for treated water or chemical additives.
• Halimbawa: Municipal water distribution networks employ butterfly flange valves for diameters exceeding 12 pulgada, ensuring maintenance-friendly operation.

Industriya ng Langis at Gas

• Paglalapat: Crude oil pipelines, refined products, gas distribution, at mga platform sa malayo sa pampang.
• Mga kalamangan: High-pressure tolerance (Klase ng ANSI 600 and above), bidirectional flow capability, compatibility with hydrocarbons and corrosive fluids.
• Halimbawa: Double or triple eccentric flanged butterfly valves control oil and gas pipelines where minimal leakage and high reliability are mandatory.

Pagbuo ng Kapangyarihan

• Paglalapat: Steam, cooling water, and feedwater systems in thermal and nuclear plants.
• Mga kalamangan: Mataas na temperatura tolerance, tight sealing for steam lines, rapid quarter-turn actuation for safety.
• Halimbawa: Triple eccentric butterfly flange valves handle superheated steam at 482°C in power plant feedwater lines.

Pagproseso ng Kemikal at Petrochemical

• Paglalapat: Aggressive chemicals, mga asido, and high-temperature processes.
• Mga kalamangan: Material versatility (316L, Bilisan mo na, Duplex 2205), precise throttling, minimal friction for controlled flow.
• Halimbawa: Eccentric flanged butterfly valves with metal seats prevent leakage in sulfuric acid or caustic soda lines.

Pag init ng katawan, Bentilasyon, at Air Conditioning (HVAC) and Industrial Chilled/Hot Water Systems

• Paglalapat: Flow regulation in chilled water loops, cooling towers, and heating systems.
• Mga kalamangan: Epektibo ang gastos, magaan ang timbang, low-pressure rating suitable for non-critical applications, easy maintenance.
• Halimbawa: Concentric butterfly flange valves regulate building-wide chilled water distribution efficiently.

Pagkain, Beverage, and Pharmaceutical Industries

• Paglalapat: Sanitary processing lines, CIP (Malinis na Lugar) mga sistema.
• Mga kalamangan: Electropolished stainless steel, FDA-approved seats, smooth surfaces eliminate bacterial growth zones.
• Halimbawa: Flanged butterfly valves with EPDM or PTFE seals ensure hygienic flow control in beverage bottling plants.

Mining and Slurry Handling

• Paglalapat: Tailings pipelines, slurry transport, and water control.
• Mga kalamangan: Robust construction, abrasion-resistant discs and seats, compatibility with viscous or particle-laden fluids.
• Halimbawa: Carbon steel double flanged butterfly valve with hardened seats handle mineral slurries without rapid wear.

10. Comparison with Other Valves

11. Pangwakas na Salita

Ang flanged butterfly valve is a versatile and cost-efficient solution for fluid control, offering a balance of compact design, high flow capacity, and reliable sealing.

Its adaptability to different materials, Mga klase ng presyon, and actuation methods makes it indispensable across industries ranging from municipal water to petrochemicals.

For engineers and procurement teams, selecting the right FBV involves evaluating media compatibility, mga kondisyon ng pagpapatakbo, performance metrics, and lifecycle costs.

With ongoing advances in materials and automation, flanged butterfly valves will remain a cornerstone of industrial flow control.

Custom Valves from DEZE Foundry

From water treatment plants and HVAC systems to oil & gas pipelines, mga reaktor ng kemikal, and power generation networks, flanged butterfly valves deliver precise flow regulation and tight shutoff under demanding conditions.

Their quarter-turn operation, compact structure, and wide material options enable customization for specific fluids, mga pressure, and temperatures.

As a professional valve foundry and supplier, nagbibigay kami ng custom-engineered flanged butterfly valves and precision-cast components, meeting international standards (API, ISO, ANSI) while ensuring cost-effective performance.

Whether your project requires large-diameter high-pressure service, Mga haluang metal na lumalaban sa kaagnasan, or optimized designs for maintenance efficiency, our manufacturing expertise ensures reliable solutions tailored to your industry.

Makipag ugnay sa Amin now！

Mga FAQ

Can flanged butterfly valves handle high-pressure gas service?

Yes—double/triple eccentric flanged valves with metal seats (API 609 Class VI leakage) and ANSI Class 300–900 ratings are suitable for high-pressure gas (hal., natural na gas, nitrogen).

Ensure compliance with ISO 15848-1 Class AH for low fugitive emissions.

What is the maximum size of a flanged butterfly valve?

Most manufacturers offer flanged butterfly valves up to 48 pulgada (1200 mm) sa diameter, suitable for large water treatment plants and oil & gas pipelines.

Custom designs can reach 60 pulgada (1500 mm) for specialized applications.

How do I prevent flange gasket leakage?

Use gaskets compatible with fluid/temperature (hal., graphite for steam, PTFE for chemicals); tighten bolts in a crisscross pattern (per ASME PCC-1) to uniform torque (hal., 70 N·m for 6-inch ANSI 300 mga flanges); replace gaskets annually.

Are flanged butterfly valves suitable for sanitary service?

Yes—select 316L bodies with electropolished surfaces (Ra ≤0.8 μm), PTFE seats, and tri-clamp flanges (3-A/EHEDG compliant).

These valves are used in dairy, inumin, and pharmaceutical manufacturing.

What is the difference between ANSI Class 300 at 600 flanged valves?

Klase ng ANSI 300 valves handle up to 70 bar (20°C), habang Klase 600 handles up to 140 bar (20°C).

Klase 600 valves have thicker bodies (20–30 mm vs. 15–20 mm for Class 300) and stronger flanges, making them suitable for high-pressure applications like refineries and offshore pipelines.