What is a butterfly valve and how does it work?

A butterfly valve is a quarter-turn valve with a circular disc mounted on a shaft (stem) in the center of the pipe. When the handle or actuator rotates 90 degrees, the disc turns from parallel to the flow (fully open) to perpendicular to the flow (fully closed). Butterfly valves are compact, lightweight, and cost-effective – especially for large diameter pipelines. They can be used for both isolation (on/off) and throttling (flow control).

What is the difference between concentric, double offset, and triple offset butterfly valve?

Concentric (zero offset): Stem centered in disc, rubber seat (EPDM/NBR), PN10-PN16, for water and HVAC, most economical. Double offset (high performance): Stem offset from disc center and body center, reduces seat friction, PTFE or metal seat, PN25-PN40 / Class 150-300, for oil and gas and chemical. Triple offset (metal seated): Three offsets create cam action, metal-to-metal seat (Stellite/SS), zero leakage, Class 150-600, for high temperature, high pressure, and critical service. Cost increases with offset number but so does performance and pressure rating.

What is the difference between wafer and lug butterfly valve?

Wafer butterfly valve: Sandwiched between two flanges using through-bolts. Cannot be used as end-of-line valve. Lighter and cheaper. Most common for general service. Lug butterfly valve: Has threaded inserts (lugs) in the body. Each flange is bolted independently. Can be used as end-of-line valve (one flange can be removed while the other holds the valve). Used where downstream piping may need to be disconnected for maintenance. Double flanged: Has integral flanges on both sides. Heaviest and most expensive. Used for large sizes and high-pressure applications.

What is API 609 butterfly valve?

API 609 is the American Petroleum Institute standard for butterfly valves used in petroleum and natural gas industries. It covers two categories: Category A – concentric design, resilient seated, wafer or lug, for general service. Category B – double or triple offset, high performance, metal or soft seated, for critical service. API 609 specifies design, materials, dimensions, testing (per API 598), and marking. It is the primary standard for butterfly valves in oil and gas applications.

What seat materials are used in butterfly valves?

Butterfly valve seat materials: EPDM – best for water, wastewater, and HVAC (-40°C to +120°C). NBR (Nitrile) – for oil and petroleum products (-20°C to +80°C). Viton (FKM) – for chemicals, acids, and high temperature (-20°C to +200°C). PTFE – for aggressive chemicals, food grade, wide temperature range (-200°C to +260°C). Metal seat (Stellite/SS) – for high temperature, high pressure, and fire-safe applications (up to 400°C+). Choose seat material based on media compatibility and temperature.

What is the difference between butterfly valve and ball valve?

Both are quarter-turn valves but: Butterfly valve – disc always remains in the flow path (even when open), lower cost for large sizes, lighter weight, better for large diameters (6 inch to 72 inch), good for throttling, moderate pressure drop. Ball valve – ball retracts completely from flow path when open, bubble-tight shut-off, higher cost for large sizes, better for small to medium sizes (1/2 to 12 inch), minimal pressure drop when fully open. Use butterfly for large diameter and cost-sensitive applications. Use ball valve for tight shut-off and small to medium sizes.

What sizes are butterfly valves available in?

Supreme Valves supplies butterfly valves from 2 inch (DN50) to 72 inch (DN1800). Concentric (resilient seated): 2 to 48 inch, PN10/PN16, wafer and lug. Double offset (high performance): 3 to 60 inch, PN25/Class 150-300, wafer, lug, and flanged. Triple offset (metal seated): 3 to 72 inch, Class 150-600, flanged and butt weld. Body materials: Cast Iron (GG25), Ductile Iron (GGG40/50), Carbon Steel (WCB), Stainless Steel (CF8M). Contact +91 97732 78770 for pricing.

Can butterfly valves be used for throttling?

Yes, butterfly valves can be used for throttling, but with limitations. Concentric butterfly valves provide basic throttling for water and HVAC applications. Double offset butterfly valves provide better throttling with reduced seat wear. Triple offset butterfly valves provide precise throttling with linear flow characteristics. For critical flow control, use butterfly valves with positioners and actuators. Note: butterfly valves have a non-linear flow characteristic – most flow change occurs in the first 60 degrees of opening. For precise throttling, globe valves or V-port ball valves may be better choices.

Quarter-Turn Valves

Butterfly Valves – Concentric, Double & Triple Offset

Name: Butterfly Valve
Brand: Supreme Valves
SKU: SV-BUTTERFLYVALVE
Price: 500 INR
Availability: InStock
Rating: 4.8 (127 reviews)

Industrial butterfly valves from Supreme Valves India. Concentric (resilient seated), double offset (high performance), and triple offset (metal seated) designs. Wafer, lug, and double flanged. API 609, BS EN 593 certified. CI, DI, WCB, SS316. Sizes 2" to 72". PN10 to Class 600.

Key Applications

HVACWater DistributionFood Processing

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Quick Summary – What is a Butterfly Valve?

Butterfly valve = quarter-turn valve with a circular disc on a shaft. Rotate 90° → disc turns from parallel (open) to perpendicular (closed) to flow. Compact, lightweight, cost-effective for large diameters. Three offset designs: Concentric (zero offset, rubber seat, PN10-16, water/HVAC), Double offset (high performance, PTFE/metal seat, PN25-40, oil & gas), Triple offset (metal-to-metal, Class 150-600, critical service). Body styles: wafer, lug, double flanged. Standards: API 609, BS EN 593. Sizes: 2" to 72".

Butterfly Valve Types by Offset Design

Butterfly valves are classified by their offset geometry. The offset design determines pressure rating, temperature capability, and service life. Choose the right type for your application:

Concentric (Zero Offset)

Stem centered in disc. Most economical design with resilient rubber seat. Ideal for low-pressure water, HVAC, and general industrial applications.

Pressure: PN10-PN16, Class 150
Temperature: -20°C to +120°C
Seat: EPDM, NBR, Viton, PTFE

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Double Offset (High Performance)

Two offsets create cam-action seating, reducing friction and wear. Suitable for higher pressures and throttling service in oil & gas and power plants.

Pressure: PN16-PN40, Class 150-300
Temperature: -46°C to +400°C
Seat: PTFE, RPTFE, Metal

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Triple Offset (Metal Seated)

Three offsets with conical seat geometry for zero-friction metal-to-metal sealing. Fire-safe, suitable for highest pressures and extreme temperatures.

Pressure: PN10-PN420, Class 150-2500
Temperature: -196°C to +815°C
Seat: Stellite, Inconel, Hastelloy

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Technical Specifications

Product Type	Butterfly Valve
Category	Quarter-Turn Valves
Size Range	1/2" to 48" (DN15 to DN1200)
Pressure Class	150# to 2500# (PN10 to PN420)
End Connections	Flanged, Threaded, Socket Weld, Butt Weld
Operation	Manual, Gear Operated, Electric Actuated, Pneumatic Actuated
Standards	ASME B16.34, API 600, API 602, BS 1873, DIN 3352

Material Options

Carbon Steel

ASTM A216 WCB, A105, A350 LF2

Stainless Steel

SS304, SS316, SS316L, SS321, SS347

Alloy Steel

ASTM A217 WC6, WC9, C5, C12

Duplex Steel

F51, F53, F55, Super Duplex

Exotic Alloys

Monel, Hastelloy, Inconel, Titanium

Bronze & Brass

Gunmetal, Aluminum Bronze, Naval Brass

Features & Benefits

High Performance

Designed for reliable operation under demanding conditions with minimal maintenance requirements.

Quality Assurance

Complete material traceability, mill test certificates, and compliance with international standards.

Wide Application Range

Suitable for HVAC, Water Distribution, Food Processing and many other industrial applications.

Expert Support

Technical assistance for valve selection, sizing, and application engineering from our experienced team.

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Test Type	Pressure	Standard
Hydrostatic Body Test	425 PSI (Class 150)	API 598
Seat Test	300 PSI (Class 150)	API 598
Air Test	80 PSI	API 598

Part Name	Material Specification
Body	ASTM A351 Gr. CF8/CF8M/CF3/CF3M, ASTM A216 WCB, Cast Iron
Ball/Disc	AISI 304/316/304L/316L Stainless Steel
Stem	AISI 304/316/304L/316L, AISI 410
Seat/Seal	PTFE, Reinforced PTFE, Graphite
Gaskets	Spiral Wound Metallic, PTFE, Graphite
Bolting	ASTM A193 Gr. B7/B8, Carbon Steel

Butterfly Valves – Concentric, Double & Triple Offset

Key Applications

Quick Summary – What is a Butterfly Valve?

Butterfly Valve Types by Offset Design

Concentric (Zero Offset)

Double Offset (High Performance)

Triple Offset (Metal Seated)

Technical Specifications

Material Options

Carbon Steel

Stainless Steel

Alloy Steel

Duplex Steel

Exotic Alloys

Bronze & Brass

Features & Benefits

High Performance

Quality Assurance

Wide Application Range

Expert Support

Request a Quote

Related Products

Technical Specifications

Design & Exporting

Testing & Inspection

Pressure Rating

Temperature Rating

Test Pressure Requirements

Materials of Construction

Size Range & End Connections

Technical Notes

Standards Compliance