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Double Offset Butterfly Valve – High Performance (HPBV)
The double offset (double eccentric) butterfly valve features two geometric offsets that create a cam-action seating mechanism. This reduces friction and wear, enabling higher pressure ratings and longer service life compared to concentric designs.
What is Double Offset?
1st Offset: Stem is positioned behind the disc centerline.
2nd Offset: Stem is offset from the pipe/body centerline.
This creates a cam effect that lifts the disc off the seat during opening, reducing wear.
Key Standards
Size Range: DN50 to DN1200 (2" to 48") | Pressure: PN16 to PN40, Class 150-300
Technical Specifications
Valve Type
Double Offset (Double Eccentric)
Design Standard
API 609 Cat B, BS EN 593
Face to Face
API 609, EN 558-1 Series 13/14
Testing Standard
API 598, BS EN 12266
Pressure Rating
PN16, PN25, PN40, Class 150-300
Size Range
DN50 - DN1200 (2" - 48")
End Connection
Wafer, Lug, Double Flanged
Flange Standard
ASME B16.5, EN 1092-1
Operation
Lever, Gear, Pneumatic, Electric
Seat Type
Soft Seated / Metal Seated
Temperature Range
-46°C to +400°C
Leakage Class
Class VI (Bi-directional)
Material of Construction Options
Dimension Table (Double Flanged)
Key Advantages
Reduced Seat Wear
Cam-action seating lifts disc off seat during rotation, minimizing friction and extending seat life.
Higher Pressure Ratings
Suitable for PN25, PN40, and Class 300 applications where concentric valves cannot be used.
Throttling Capability
Excellent flow control characteristics for modulating service applications.
Lower Maintenance
Reduced wear means less frequent maintenance and lower total cost of ownership.
Applications
Oil & Gas
Pipelines, refineries, terminals
Power Generation
Steam, cooling water, condensate
Chemical Processing
Acids, alkalis, solvents
Marine & Offshore
Ballast, seawater, cargo
Frequently Asked Questions
What is a double offset butterfly valve?
A double offset butterfly valve has two offsets: the stem is offset from the disc center (1st offset) and from the pipe/body center (2nd offset). This design reduces friction between disc and seat, minimizing wear and extending service life.
What is the difference between single and double offset butterfly valve?
A single offset valve has only one offset (stem behind disc center), while a double offset has two offsets. Double offset provides cam-action seating, reducing seat wear and allowing higher pressure ratings up to PN40/Class 300.
What is API 609 Category B?
API 609 Category B covers high-performance butterfly valves designed for more demanding applications. These valves have offset disc design, can handle higher pressures (Class 150-600), and are suitable for throttling service.
When should I use a double offset butterfly valve?
Use double offset butterfly valves when you need: higher pressure ratings (above PN16), longer service life, reduced maintenance, throttling applications, or when handling abrasive or particulate media.
What is the maximum pressure for double offset butterfly valve?
Double offset butterfly valves can handle pressures up to PN40 (40 bar/580 PSI) or ANSI Class 300 (50 bar/720 PSI) depending on size and material. For higher pressures, triple offset butterfly valves are recommended.
Compare Butterfly Valve Types
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