Double Eccentric Design: Engineering the "Double Offset"
The Double Eccentric Butterfly Valve is defined by two distinct offsets in its design that significantly improve performance over standard concentric valves:
- First Offset: The shaft is located behind the centerline of the sealing surface.
- Second Offset: The shaft is located slightly to one side of the pipe's vertical centerline.
The "Camming" Effect
This dual-offset geometry creates a "cam-like" motion. As the valve begins to open, the disc lifts immediately off the seat rather than rubbing against it. This minimizes friction, reduces operating torque, and dramatically extends the service life of the seal.
Why Choose Double Eccentric over Gate Valves?
In large-diameter pipelines, especially in Mumbai, Gujarat, and international projects, the Double Offset Butterfly Valve is often preferred over gate valves for several strategic reasons:
- Cost-Effectiveness: Especially in sizes above 300mm, butterfly valves are significantly lighter and more economical to manufacture and install.
- Space Efficiency: They have a much shorter "face-to-face" dimension, requiring less space in valve pits and allowing for shallower burial depths in underground applications.
- Low Torque: The eccentric design allows for smaller, more affordable actuators (pneumatic, electric, or manual gear).
- Durability: Because the disc only contacts the seat at the final point of closure, seat wear is minimized, ensuring a reliable seal even after thousands of cycles.
Technical Specifications (2026 Range)
Feature | Details |
Body Material | Ductile Iron (DI), Cast Steel (WCB), Stainless Steel (CF8M) |
Disc Material | Ductile Iron (Epoxy Coated), SS304, SS316, Duplex Steel |
Shaft Material | SS410, SS316, or 17-4 PH Stainless Steel |
Seat Material | EPDM, Nitrile (NBR), or Reinforced PTFE |
Pressure Rating | PN10, PN16, PN25, Class 150# |
Operation | Handwheel with Gearbox, Pneumatic, or Electric Actuator |
Strategic Industrial Applications
1. Water Supply & Distribution
Commonly used in municipal water mains and underground networks. Their compact profile allows for smaller valve chambers, reducing civil construction costs.
2. Power Generation
Ideal for circulating water systems and cooling tower isolation where large volumes of water must be managed with minimal pressure drop.
3. Wastewater Treatment
Used in secondary treatment processes and effluent discharge lines where a robust, high-cycle valve is required.
4. Desalination Plants
When manufactured with Duplex Steel or high-grade Stainless Steel, these valves excel in handling corrosive seawater.
FlowBiz Exports: A Legacy of Quality
As a leading Butterfly Valve manufacturer in India, FlowBiz Exports delivers precision-engineered solutions to the most critical sectors. Our products are trusted across Dubai, Turkey, Africa, and Southeast Asia, as well as major Indian industrial hubs like Vapi, Dahej, Ahmedabad, and Pune.
Is your large-scale water project requiring a space-saving, low-maintenance isolation solution?
The FlowBiz Double Eccentric Butterfly Valve is the modern engineering choice. Contact our technical team today at +91 9016 989898 for a formal quote, technical data sheets, and assistance with selecting the right material for your specific environment.
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