ফ্ল্যাঞ্জড প্রজাপতি ভালভ – শীর্ষস্থানীয় ফাউন্ড্রি দ্বারা কাস্টম ভালভ

1. ভূমিকা

A Flanged butterfly valve (এফবিভি) 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 টাইট শাটফ, structural reliability, and ease of maintenance.

একই সময়ে, their versatility makes them indispensable in জল চিকিত্সা, HVAC networks, and general industrial processing, where their compact design, cost-efficiency, and adaptability across pressure and temperature ranges deliver long-term operational value.

2. What is a Flanged Butterfly Valve?

Core Definition and Working Principle

ক flanged butterfly valve (এফবিভি) একটি quarter-turn rotary valve 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:

• Fully Open (0°): The disc lies parallel to flow, minimizing pressure loss (typically 1–3 psi for a 6-inch valve at nominal flow).
• থ্রোটলিং (10–80°): Partial rotation restricts flow; eccentric disc designs provide more linear flow control than concentric types.
• Fully Closed (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

দ্য 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, sealing কর্মক্ষমতা, torque requirements, এবং অ্যাপ্লিকেশন উপযুক্ততা.

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.

কর্মক্ষমতা মেট্রিক্স:

• Pressure Rating: ANSI Class 150–300 (28–70 bar at 20°C)
• Leakage Class: এপিআই 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)

সুবিধা:

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

সীমাবদ্ধতা:

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

সাধারণ অ্যাপ্লিকেশন:

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

Eccentric Flanged Butterfly Valves (High-Performance Design)

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

These designs are ideal for উচ্চ চাপ, high-temperature, and gas applications.

Single Eccentric (Offset Disc) ফ্ল্যাঞ্জড প্রজাপতি ভালভ

Design: The disc center is offset from the stem axis, which minimizes contact with the seat during rotation, reducing friction.

কর্মক্ষমতা মেট্রিক্স:

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

অ্যাপ্লিকেশন:

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

Double Eccentric (Offset Disc + স্টেম) ফ্ল্যাঞ্জড প্রজাপতি ভালভ

Design: 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.

কর্মক্ষমতা মেট্রিক্স:

• Pressure Rating: ANSI Class 600 (140 bar at 20°C); up to Class 900 with metal seats
• Leakage Class: এপিআই 609 ষষ্ঠ শ্রেণি (≤0.00001% of nominal flow) — suitable for gas service, including natural gas pipelines
• তাপমাত্রা ব্যাপ্তি: -29°C to 482°C (metal seats)

অ্যাপ্লিকেশন:

• রাসায়নিক প্রক্রিয়াজাতকরণ
• তেল & gas pipelines
• Steam systems
• High-pressure industrial fluids requiring tight shutoff

Triple Eccentric (অফসেট + Tapered Disc) ফ্ল্যাঞ্জড প্রজাপতি ভালভ

Design: 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.

কর্মক্ষমতা মেট্রিক্স:

• Pressure Rating: ANSI Class 900 (210 bar at 20°C)
• তাপমাত্রা ব্যাপ্তি: -29°C to 650°C (Stellite® or hard metal seats)
• Cycle Life: 50,000-100,000 চক্র (metal seat durability)

অ্যাপ্লিকেশন:

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

সারাংশ:

4. উপকরণ & Seals of Flanged Butterfly Valve

পারফরম্যান্স, নির্ভরযোগ্যতা, and longevity of double flanged butterfly valves (FBVs) are strongly influenced by উপাদান নির্বাচন for the body, ডিস্ক, স্টেম, and sealing elements.

Proper materials ensure compatibility with the fluid, resistance to corrosion, high-pressure handling, and suitability for temperature extremes.

Body Materials

The valve body is the primary pressure boundary and must withstand mechanical stress, internal pressure, 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 যান্ত্রিক শক্তি, জারা প্রতিরোধের, and sealing compatibility:

• 316 স্টেইনলেস স্টিল: Widely used for general-purpose chemical, জল, and steam applications.
• হেসটেলয় সি 276: Resistant to oxidizing and reducing chemicals; suitable for aggressive acids.
• Ductile Iron with PTFE Coating: Low-friction, corrosion-resistant option for water and mild chemicals.
• স্টেলাইট®-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 mechanical stress, চাপ, and fluid contact. Common materials:

Seat Materials and Seal Types

দ্য seat forms the critical sealing interface with the disc, determining leakage class, torque requirement, and service life. Selection depends on তরল প্রকার, চাপ, and temperature.

Gaskets and Actuator Interfaces

• Flange Gaskets: গ্রাফাইট, 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. উত্পাদন & Foundry Methods of Flanged Butterfly Valves

এর উৎপাদন flanged butterfly valves (FBVs) requires high precision, robust materials, and strict adherence to international standards such as API 609, আইএসও 5752, and ANSI B16.5.

Valves designed for high-pressure and high-performance applications—like oil & gas pipelines, রাসায়নিক উদ্ভিদ, and power generation—must exhibit মাত্রিক নির্ভুলতা, কাঠামোগত অখণ্ডতা, 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 ইঞ্চি), বালি ing ালাই is widely used.

এই প্রক্রিয়ায়, 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, বিনিয়োগ কাস্টিং (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 মিমি) এবং মসৃণ পৃষ্ঠতল, enabling precise features such as double eccentric disc hubs.
Investment casting is ideal for 316L stainless steel, তাড়াতাড়ি, or other corrosion-resistant alloys.

ফরজিং: High-Strength Components

Forging is the preferred method for critical, high-pressure components such as bodies, 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, power plants, 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.

মেশিনিং: Precision Finishing

After casting or forging, সিএনসি মেশিনিং ensures high dimensional accuracy, পৃষ্ঠ সমাপ্তি, 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.

তাপ চিকিত্সা: Mechanical and Corrosion Properties

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

• কার্বন ইস্পাত (WCB): Quenched at 850°C and tempered at 650°C to achieve tensile strength ≥485 MPa.
• 316এল স্টেইনলেস স্টিল: Solution-annealed at 1050–1100°C followed by water quenching to restore corrosion resistance and homogenize microstructure.
• দ্বৈত 2205: Solution-annealed at 1020–1080°C to achieve a balanced austenite/ferrite ratio (50:50), optimizing both strength and corrosion resistance.

সারফেস ট্রিটমেন্ট: Longevity & জারা প্রতিরোধের

Surface finishing ensures durability in harsh environments:

• প্যাসিভেশন 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.
• ইলেক্ট্রোপোলিশিং is used in sanitary applications (খাদ্য, পানীয়, ফার্মাসিউটিক্যালস) to achieve Ra ≤0.8 μm, eliminating microscopic crevices and bacterial dead zones.

সমাবেশ & গুণগত নিশ্চয়তা

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: বিয়ারিংস, প্যাকিং, and O-rings are fitted, and torque is verified.
• Hydrostatic or pneumatic testing: Confirms leak-tight performance under design pressure.
• অ-ধ্বংসাত্মক পরীক্ষা (এনডিটি): Methods such as X-ray, ultrasonic, or dye penetrant inspections detect internal defects.
• Actuator calibration: ম্যানুয়াল, বৈদ্যুতিক, বায়ুসংক্রান্ত, or hydraulic actuators are tested for torque and stroke accuracy.

6. Pressure Ratings, Sizes & মান

Flanged butterfly valves (FBVs) are designed for reliability across a wide range of pressures, sizes, 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 Series 10 or API 609 for easy interchangeability.

Key Standards & Certifications

7. Actuation & Control Systems

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

Actuator selection depends on valve size, torque requirement, তরল প্রকার, 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, রাসায়নিক ডোজ, 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

দ্য flanged end design is the defining characteristic of butterfly flange valves, ensuring a 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 dimensions, bolt-hole patterns, and pressure ratings. The most common standards include:

Dimensional Geometry

The flanged end geometry typically includes:

• Raised Face (আরএফ): 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 (আপ 210 বার, 650° সে).

9. Industrial Applications of Flanged Butterfly Valves

Flanged butterfly valves are বহুমুখী, high-performance quarter-turn valves widely used across industrial sectors due to their reliability, compact design, and adaptability to a broad range of pressures, তাপমাত্রা, and fluids.

Water and Wastewater Treatment

• আবেদন: Flow isolation, রাসায়নিক ডোজ, and backwashing systems.
• সুবিধা: Tight shutoff, low-pressure drop, corrosion-resistant seats for treated water or chemical additives.
• উদাহরণ: Municipal water distribution networks employ butterfly flange valves for diameters exceeding 12 ইঞ্চি, ensuring maintenance-friendly operation.

তেল ও গ্যাস শিল্প

• আবেদন: Crude oil pipelines, refined products, gas distribution, and offshore platforms.
• সুবিধা: High-pressure tolerance (ANSI Class 600 and above), bidirectional flow capability, compatibility with hydrocarbons and corrosive fluids.
• উদাহরণ: Double or triple eccentric flanged butterfly valves control oil and gas pipelines where minimal leakage and high reliability are mandatory.

বিদ্যুৎ উত্পাদন

• আবেদন: বাষ্প, শীতল জল, and feedwater systems in thermal and nuclear plants.
• সুবিধা: High-temperature tolerance, tight sealing for steam lines, rapid quarter-turn actuation for safety.
• উদাহরণ: Triple eccentric butterfly flange valves handle superheated steam at 482°C in power plant feedwater lines.

রাসায়নিক

• আবেদন: Aggressive chemicals, অ্যাসিড, and high-temperature processes.
• সুবিধা: উপাদান বহুমুখিতা (316এল, তাড়াতাড়ি, দ্বৈত 2205), precise throttling, minimal friction for controlled flow.
• উদাহরণ: Eccentric flanged butterfly valves with metal seats prevent leakage in sulfuric acid or caustic soda lines.

গরম করা, বায়ুচলাচল, and Air Conditioning (এইচভিএসি) and Industrial Chilled/Hot Water Systems

• আবেদন: Flow regulation in chilled water loops, cooling towers, and heating systems.
• সুবিধা: ব্যয়বহুল, লাইটওয়েট, low-pressure rating suitable for non-critical applications, easy maintenance.
• উদাহরণ: Concentric butterfly flange valves regulate building-wide chilled water distribution efficiently.

খাবার, Beverage, and Pharmaceutical Industries

• আবেদন: Sanitary processing lines, CIP (Clean-in-Place) সিস্টেম.
• সুবিধা: Electropolished stainless steel, FDA-approved seats, smooth surfaces eliminate bacterial growth zones.
• উদাহরণ: Flanged butterfly valves with EPDM or PTFE seals ensure hygienic flow control in beverage bottling plants.

Mining and Slurry Handling

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

10. Comparison with Other Valves

11. উপসংহার

দ্য 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, pressure classes, 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, operating conditions, 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, রাসায়নিক চুল্লি, 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, pressures, and temperatures.

As a professional valve foundry and supplier, we provide custom-engineered flanged butterfly valves and precision-cast components, meeting international standards (এপিআই, আইএসও, ANSI) while ensuring cost-effective performance.

Whether your project requires large-diameter high-pressure service, corrosion-resistant alloys, or optimized designs for maintenance efficiency, our manufacturing expertise ensures reliable solutions tailored to your industry.

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FAQS

Can flanged butterfly valves handle high-pressure gas service?

Yes—double/triple eccentric flanged valves with metal seats (এপিআই 609 Class VI leakage) and ANSI Class 300–900 ratings are suitable for high-pressure gas (যেমন, natural 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 ইঞ্চি (1200 মিমি) in diameter, suitable for large water treatment plants and oil & gas pipelines.

Custom designs can reach 60 ইঞ্চি (1500 মিমি) for specialized applications.

How do I prevent flange gasket leakage?

Use gaskets compatible with fluid/temperature (যেমন, graphite for steam, PTFE for chemicals); tighten bolts in a crisscross pattern (per ASME PCC-1) to uniform torque (যেমন, 70 N·m for 6-inch ANSI 300 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, পানীয়, and pharmaceutical manufacturing.

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

ANSI Class 300 valves handle up to 70 বার (20° সে), while Class 600 handles up to 140 বার (20° সে).

ক্লাস 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.