Concentric Resilient-Seated Butterfly Valve
Wafer
Lug
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The disc rotates around the central shaft axis. The resilient seat seals against the disc through elastic interference.
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Commonly PN 6–PN 16 or Class 150, depending on size, design, and applicable standard.
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EPDM, NBR, FKM, PTFE, or other qualified elastomers selected according to the medium.
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Often used from approximately −20°C to 120°C, but the actual limit depends on the seat compound, pressure, and medium.
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Potable and process water, HVAC, irrigation, fire-water systems, air handling, and general utility pipelines.
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Compact design, low weight, low purchase cost, simple maintenance, and good shut-off performance for clean fluids.
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Elastomer limitations may restrict high-temperature, abrasive, aggressive, or hydrocarbon service. Seat wear can increase with frequent cycling.
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API 609, EN 593, ISO 10631, ISO 5208, API 598, ISO 5752, and the applicable flange standard.
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Confirm seat compatibility, potable-water approvals where required, shaft and disc materials, leakage class, face-to-face dimension, actuator interface, and pressure rating at operating temperature.
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Standard choice for cost-sensitive utility service |
High-Performance Double-Offset Butterfly Valve
Wafer
Lug
Flanged
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The shaft is offset from the disc centerline and the seat centerline, reducing rubbing between the disc and seat during opening.
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Commonly PN 10–PN 40 or Class 150–Class 300, subject to design and size.
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Laminated metal-graphite seats, PTFE-based seats, reinforced polymer seats, or other engineered sealing systems.
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Commonly suitable for higher temperatures than resilient-seated designs; actual limits may range from approximately −40°C to 300°C or more depending on construction.
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District energy, cooling water, compressed air, industrial water, low-pressure steam, and selected process services.
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Lower operating torque than a concentric design at comparable size, improved cycle life, and broader pressure-temperature capability.
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Higher cost and more complex specification. Metal or laminated seats may require careful installation and may not provide the same soft-seat tightness in every service.
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API 609, EN 593, ISO 10631, ISO 5208, API 598, ISO 5752, ASME B16.34, and applicable flange standards.
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Verify offset geometry, seat construction, bidirectional or unidirectional shut-off, torque curve, fire-safe requirements, fugitive-emission requirements, and actuator sizing.
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Preferred for demanding industrial duty |
Triple-Offset Metal-Seated Butterfly Valve
Flanged
High Temperature
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Three geometric offsets create a cam-like, non-rubbing movement between the sealing surfaces. The sealing contact is typically metal-to-metal.
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Commonly PN 16–PN 100 or Class 150–Class 600, depending on size and design qualification.
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Stainless steel, nickel-based alloys, hardfacing alloys, graphite, or other qualified metallic and fire-resistant sealing systems.
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Frequently selected for high-temperature service, with some designs rated above 500°C. The rating must be confirmed from the manufacturer’s pressure-temperature chart.
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Steam, hot gas, thermal oil, refinery and chemical process lines, high-temperature utilities, and critical isolation duties.
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Excellent high-temperature capability, low seat wear, fire-safe potential, low emissions when properly engineered, and long service life.
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Higher acquisition cost, higher actuation torque, stricter installation requirements, and greater sensitivity to incorrect sizing or alignment.
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API 609, EN 593, ISO 10631, ISO 5208, API 598, API 607 or ISO 10497 where fire testing is required, and ISO 15848 where fugitive emissions apply.
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Request fire-test certificates, emission test data, material certificates, torque calculations, thermal-cycle data, disc clearance details, and complete pressure-temperature ratings.
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Best for high-temperature and critical isolation |
Soft-Seated Lug-Style Butterfly Valve
Dead-End Service
Section Isolation
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The valve is secured with threaded lugs or tapped holes around the body, allowing one pipeline side to be removed in many applications.
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Commonly PN 6–PN 16 or Class 150, with higher ratings available for specific designs.
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EPDM, NBR, FKM, PTFE, or other elastomers and polymers.
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Usually limited by the selected seat material; many water-service designs operate within approximately −20°C to 120°C.
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Water treatment, pump isolation, HVAC equipment, tank farms, fire-water systems, and compact plant layouts requiring sectional maintenance.
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Supports convenient line-section isolation, compact installation, and relatively simple replacement or maintenance.
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Not every lug design is rated for dead-end service at full pressure. Bolt loading, flange alignment, and allowable end-of-line pressure require confirmation.
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API 609, EN 593, ISO 10631, ISO 5208, API 598, ISO 5752, and the relevant flange and bolting standards.
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Confirm dead-end rating, flange drilling, lug-hole dimensions, bolt length, body pressure rating, seat material, and whether downstream removal is permitted.
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Useful where maintenance isolation is important |
Wafer Butterfly Valve
Lightweight
Low Cost
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The valve body is clamped between mating pipe flanges. It normally does not provide independent flange-to-flange connection capability.
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Commonly PN 6–PN 16 or Class 150, depending on the design and nominal size.
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Commonly EPDM, NBR, FKM, PTFE, or metal-laminated seat systems.
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Determined by the seat and body materials; water-service versions are often suitable for moderate temperatures.
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HVAC, water distribution, compressed air, ventilation, irrigation, and general process utility systems.
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Short face-to-face length, low mass, reduced material consumption, and economical installation in space-constrained systems.
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Pipeline alignment is critical. It may be unsuitable for dead-end service unless specifically designed and rated for that condition.
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API 609, EN 593, ISO 10631, ISO 5208, API 598, ISO 5752, and the applicable flange drilling standard.
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Check flange compatibility, minimum pipe bore, disc clearance, bolt pattern, line pressure, dead-end limitations, and required installation orientation.
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Economical option for standard pipeline systems |
Eccentric Butterfly Valve for Slurry or Abrasive Service
Abrasion Control
Process Duty
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An offset disc and reinforced sealing arrangement reduce continuous rubbing and can be combined with abrasion-resistant wetted materials.
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Rating varies widely; common selections include PN 10–PN 40 or Class 150–Class 300.
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Reinforced elastomers, polyurethane, PTFE compounds, metal seats, hardfaced alloys, or replaceable wear components.
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Highly service-dependent. Abrasive concentration, particle size, velocity, and temperature must be evaluated together.
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Mining slurry, mineral processing, wastewater with solids, ash handling, pulp-related duties, and selected bulk-material processes.
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Can provide improved wear resistance and lower maintenance frequency when the seat and disc materials match the slurry conditions.
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Incorrect material selection can cause rapid erosion, leakage, torque growth, or disc damage. Standard water-service valves are often unsuitable.
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API 609 or EN 593 where applicable, ISO 5208, API 598, relevant material standards, and project-specific abrasion or slurry test requirements.
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Provide solids concentration, particle size, pH, chloride content, temperature, flow velocity, pressure differential, cycling frequency, and expected service life.
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Specialist selection for abrasive media |
Actuated Butterfly Valve for Automated Process Control
Electric
Pneumatic
Modulating
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A quarter-turn electric or pneumatic actuator rotates the disc. Positioners, limit switches, solenoid valves, and control interfaces may be added.
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Based on the underlying valve design; actuator selection depends on differential pressure, breakaway torque, and safety factor.
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Seat and disc materials are chosen for the medium; actuator enclosure and electrical components are selected for the installation environment.
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Valve and actuator temperature limits must be checked separately, especially in outdoor, high-temperature, hazardous, or washdown locations.
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Water networks, building automation, energy systems, industrial utilities, renewable-energy balance-of-plant systems, and process automation.
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Enables remote operation, repeatable positioning, integration with control systems, and automated fail-safe functions when properly configured.
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Total cost and commissioning complexity are higher. Incorrect torque, duty cycle, control signal, or fail position can cause poor performance.
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ISO 5211 for actuator mounting, IEC 60529 for enclosure protection where applicable, API 609, EN 593, ISO 5208, and project control standards.
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Confirm operating torque, actuator safety factor, power supply, IP rating, hazardous-area certification if needed, duty cycle, fail position, feedback signal, and manual override.
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Required for remote and process automation |
