Double Offset Butterfly Valve
Series 2000
A double offset butterfly valve is a high-performance, quarter-turn valve with two stem offsets, creating a cam-action that minimizes seat/disc contact, reducing wear and operating torque for reliable, bubble-tight shutoff in demanding applications like water, oil, gas, and steam
Design, Manufacturing and Testing – Technology at a Glance
Allsen eccentric butterfly valves are engineered for minimal seat wear, zero-leakage shut-off, andlong service life. Suitable for uni- and bi-directional flow with low maintenance. Two-piece stem & eccentric disc design reduce seat deformation and torque.Offset geometry creates cam action that lifts the disc off the seat during opening – extending seat life.
1st offset: stems placed downstream of centerline for 360° sealing.
2nd offset: stems off vertical axis for camming effect.
Integrated mounting pad allows direct actuator or gearbox mounting.
Sealing & Seat Features
- Low torque operation with drop-tight, bi-directional sealing.
- Stainless steel wire reinforced U-shape seat for flexibility and durability.
- True interference fit — sealing without line pressure.
- Serrated retainer ring ensures seat stability under all conditions.
- Self-adjusting seat compensates for wear and temperature.
- Easy seat replacement without removing disc or stem.
Applications :
• Pharma • Military • Sour Gas • Food • Vacuum & Oxygen • Steam • Dead-End • Fire Safety
• Chemicals (e.g., Chlorine–Ammonia) • RO • Slurry • Modulating / Special Fluids.
Models: Wafer (AFV-W) • Lug (AFV-L) • Flanged (AFV-F)
Standards & Certifications
- Design standard as per EN 593 or API 609 (cat. B) as standard. Another applicable standard on
- request.
- Testing standard as per API 598 for on-off Valves and FCI 70-2 for Control Valves.
- Certificate EN10204 Type 3.1 as standard & Manufacturing under Quality system ISO 9001:
- 2015.
- Casting inspection as per MSS-SP-55 as standard. Another applicable standard on request.
- Trims available with combination of various Casting material like WCB/ CF8/ CF8M/ CF3M/ GR.
- 4A-5A/ NAB/
- Aluminum Alloys etc. and Seat Material like RTEF/ PTFE/ UHMWPE/ METAL/ FIRE SAFE.
- 100% factory tested (Hydro, Pneumatic) and Inspected valves as per standard.
Materials & Customization :
Trim: WCB, CF8, CF8M, CF3M, GR 4A-SA, NAB, Al-Alloys,etc
Seat: RTEF, PTFE, UHMWPE, Metal, Fire-Safe.
Coating & Automation as per customer needs.
Actuator/Gear Mounting: ISO 5211 standardized.
Design Highlights:
Lugged body with ANSI 150# / 300# drilling.
Two-piece shaft for higher Cv and efficient operation.
Low torque, long service life.
Lever, Gear, Pneumatic, or Electric actuation options.
Sizes & Models
AFV-W (Wafer): 2″ (DN 50) – 36″ (DN 900)
AFV-L (Lug): 2″ (DN 50) – 36″ (DN 900)
AFV-F (Flanged): 2″ (DN 50) – 24″ (DN 600)
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