What is a butterfly valve and what are its advantages for large valve applications?

A butterfly valve is a quarter-turn valve with a circular disc that rotates 90 degrees to open or close. The disc is mounted on a shaft passing through the valve body, with the disc positioned in the center of the pipe bore. Butterfly valves offer significant advantages for large sizes (above 24 inches) where gate and globe valves become prohibitively expensive and heavy. For Saudi Arabian water transmission pipelines and UAE district cooling systems, lug-wafer and double-flange butterfly valves provide cost-effective flow control. They require minimal face-to-face dimensions compared to other valve types.

What is the difference between lug-type and wafer-type butterfly valves?

Wafer-type butterfly valves are installed between two flanges using through bolts that pass through the valve body. They require full pipeline support and are not suitable for end-of-line service. Lug-type butterfly valves have threaded inserts on the bolt holes extending beyond the valve body, allowing installation as a standalone end-of-line valve or between two flanges. For Saudi Arabian fire protection systems and water distribution, lug-type valves are preferred for their versatility. Double-flange (concentric) butterfly valves are used for boiler feedwater and cooling water where higher pressure ratings are needed.

What pressure ratings are available for industrial butterfly valves?

Supreme Valves butterfly valves are available in three main pressure ratings: PN10/16 for water distribution and HVAC, PN25/40 for general industrial, and Class 150/300 for oil and gas applications. Soft-seated butterfly valves (EPDM, NBR, PTFE liner) are typically rated to PN16 or Class 150. For high-pressure oil and gas service in Saudi Arabia, metal-seated and fire-safe butterfly valves (API 609) are available up to Class 600. Triple-offset butterfly valves provide bubble-tight shut-off for critical process applications up to Class 600.

What materials are used for butterfly valves in water and wastewater applications?

For municipal water and wastewater in GCC countries, ductile iron (ASTM A395/EN1563) with epoxy coating (minimum 250 microns) provides cost-effective corrosion resistance. The disc can be ductile iron with EPDM/nylon coating or stainless steel (CF8M) for enhanced durability. For seawater cooling towers in UAE and Saudi Arabia, we recommend super austenitic stainless steel (254 SMO) or super duplex disc with EPDM seats. PTFE-lined butterfly valves are ideal for corrosive chemical service in Qatar petrochemical plants.

What is the difference between symmetric and triple-offset butterfly valves?

A symmetric (concentric) butterfly valve has the disc centered on the pipe bore with the seat sealing against the disc at all angles. This design relies on the elastic deformation of the seat material for sealing. A triple-offset butterfly valve (TOV) has three distinct offsets: the stem is offset from the disc center, the disc is offset from the body center, and the seat contact is at an angle. This geometry allows metal-to-metal sealing without seat deformation, providing fire-safe operation, bubble-tight shut-off, and extended service life for critical hydrocarbon applications.

What are the API 609 requirements for butterfly valves in oil and gas service?

API 609 covers butterfly valves for petroleum and natural gas industries, specifying requirements for design, materials, pressure testing, and fugitive emissions. Class VI seat leakage testing per API 598 is required for bubble-tight shut-off applications. Fire-safe testing per API 607/ISO 10497 verifies the valve maintains sealing capability after fire exposure. For Saudi Arabian offshore platforms and ARAMCO projects, valves must meet API 609 Category B requirements with material traceability and PMI verification. We provide complete API 609 documentation including fire test reports and fugitive emissions data.

How do I maintain butterfly valves for long-term reliability?

Regular inspection includes checking for corrosion on external components, verifying stem lubrication, and confirming actuator operation. For actuated butterfly valves, verify torque switch settings and positioner calibration. For EPDM seats, avoid exposure to petroleum-based fluids which cause swelling and premature failure. In dusty environments common to Saudi Arabian industrial areas, protect the stem/seal area from sand infiltration. For critical service, annual internal inspection is recommended to verify seat condition and disc alignment. Never use the actuator to force the valve beyond the open or closed positions.

Butterfly Valves

Double Eccentric Butterfly Valve PN25

Name: Double Eccentric Butterfly Valve PN25
Brand: Supreme Valves
SKU: 756/218-008
Rating: 4.8 (127 reviews)

Model: 756/218-008

Double eccentric butterfly valve with tilted and fixated disc for extended service life. Features integral seat, IP67 gearbox with handwheel, and SS shaft. DVGW/WRAS approved for drinking water and neutral liquids up to 70°C. Bi-directional application.

Approvals

DVGW WRAS KIWA ACS

Available Sizes: DN200 - DN1200

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Materials of Construction (MOC)

Component	Material Specification
Body & Bonnet	Ductile Iron (ASTM A536 / EN-GJS-400-15)
Stem / Spindle	SS 410 / SS 420
Seat / Trim	EPDM / NBR / Bronze

Technical Specifications

Parameter	Specification / Standard
Manufacturing / Design Standard	EN 1171 / AWWA C509 / BS 5163
Testing Standard	API 598 / EN 12266-1
Pressure Rating	PN16 / PN25

Dimension Table - PN25 (EN1092)

DN	D (mm)	L (mm)	H2 (mm)	W1 (mm)	W2 (mm)	Weight (kg)
200	250	152	217	195	287	50
250	400	165	258	228	332	77
300	400	178	303	253	368	108
350	400	190	318	285	392	118
400	400	216	373	320	435	178
450	600	222	411	345	503	238
500	600	229	455	375	564	282
600	700	267	541	430	632	448
700	700	292	566	483	706	609
800	700	318	650	546	789	805
900	700	330	707	593	839	1021
1000	700	410	771	663	909	1341
1200	700	470	899	768	1044	2175

Legend: D = Flange Drilling | L = Face-to-Face | H2 = Height | W1, W2 = Width

Key Features

Double Eccentric Design

Tilted disc releases compression after few degrees of opening for low operating torque.

Drinking Water Approved

EPDM disc seal with DVGW-WRAS-KIWA-ACS approvals for drinking water applications.

Corrosion Protection

Blue epoxy coating to GSK. Bolt holes sealed with O-rings for corrosion protection.

Bi-Directional Flow

Suitable for bi-directional application with reliable sealing in both directions.

Standards & Accessories

Standards Compliance

EN 593 Design EN 558 F2F EN 1092 Flanges IP67 Gearbox

Available Accessories

Extension Spindle
Street Cover
Dismantling Joint
Flange Adaptor

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Purchase Options

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Technical Specifications

Parameter	Specification Standard
Manufacturing Standard	IS 780 / IS 2906 / IS 14846
Testing & Inspection Standard	Hydrostatic Body: 1.5x PN, Seat: 1.0x PN
Face-to-Face Dimensions	ASME B16.10 / Manufacturer Standard
End Connections	Flanged / Screwed / Socket Weld / Butt Weld

Materials of Construction (MOC)

Part Name	Material
Body & Bonnet	Cast Iron (IS 210 Gr. FG 200)
Stem / Spindle	Stainless Steel (AISI 410)
Seat / Trim	Bronze (IS 318 LTB 2) or SS 410
Gland Packing	Graphite / PTFE (Application Dependent)
Handwheel / Actuator	Cast Iron / Steel / SG Iron

Frequently Asked Questions

What is this valve and what are its primary applications?

This industrial valve is manufactured by Supreme Valves India, a leading exporter of quality valves to Saudi Arabia, UAE, Qatar, Kuwait, Bahrain, and Oman since 2005. The valve is designed for specific applications in water treatment, oil and gas, fire protection, HVAC, and chemical process systems. Our export team provides complete technical documentation, material test certificates (MTC), and competitive pricing for Middle Eastern and global industrial buyers with full NFPA, API, ASME, and EN standard compliance.

What pressure and temperature ratings are available for this valve?

Pressure ratings typically range from Class 150 to Class 600 (PN20-PN100) depending on valve type and size. Temperature ratings depend on seat and body materials: standard PTFE seats are rated to 200 deg C, while metal seats extend service to 500+ deg C. Our engineering team can recommend the correct rating for your specific operating conditions, applicable standards (ASME B16.34, API 600/602, EN standards), and any pressure-temperature derating requirements for your application.

What materials are used in this valve's construction?

Valve body materials include Cast Iron (ASTM A126), Ductile Iron (ASTM A395), Carbon Steel (ASTM A216 WCB), Stainless Steel (CF8/CF8M), Bronze (C83600), and specialty alloys. Internal trim materials (SS304, SS316, bronze, Inconel) are selected for fluid compatibility and operating conditions. Material test certificates (MTC) per ASTM/ASME standards are provided with every export shipment, along with pressure test reports and dimensional inspection certificates.

How do I install and maintain this valve?

Installation should follow the valve's flow direction arrow and applicable standard (ASME B16.10 for face-to-face dimensions). All flanged connections require proper gaskets (full-face for cast iron, ring gaskets for steel). Initial inspection should verify stem movement is smooth and the valve seats properly. For maintenance, consult the Installation, Operation, and Maintenance (IOM) manual. Common maintenance includes periodic stem lubrication, packing adjustment or replacement, and seat inspection. Never use the valve handwheel or actuator to force a stuck gate or ball - this can damage seating surfaces.

How do I order this valve and what are the delivery terms?

Contact our export sales team via WhatsApp (+91 97732 78770) or email (supremevalvesindia@gmail.com) with your valve specification: type, size, pressure rating, body and trim materials, connection type, and quantity. We provide estimates on origin Ahmedabad or CIF/CFR to your port. Standard delivery is 3-5 weeks for in-stock items, 6-8 weeks for custom manufacture. We handle export documentation including Form A or CO (Certificate of Origin), commercial invoice, packing list, and pre-shipment inspection certificates (SGS or Bureau Veritas) upon request.