China Double Flanged Triple Offset Butterfly Valve Manufacturer, Factories
Product Description
Technical Specifications & Standards
| Size, Pressure Rating & Standard | |
|---|---|
| Size | DN40 - DN1600 |
| Pressure Rating | PN10, PN16, CL150, JIS 5K, JIS 10K |
| Face to Face STD | API609, BS5155, DIN3202, ISO5752 |
| Connection STD | PN6, PN10, PN16, PN25, 150LB, JIS 5K, 10K, 16K, GOST33259 |
| Upper Flange STD | ISO 5211 |
| Material Specifications | |
| Body | Cast Iron (GG25), Ductile Iron (GGG40/50), Carbon Steel (WCB A216), Stainless Steel (SS304 / SS316 / SS304L / SS316L), Duplex Stainless Steel (2507 / 1.4529), Bronze, Aluminium Alloy |
| Disc | DI+Ni, Carbon Steel (WCB A216), Stainless Steel (SS304 / SS316 / SS304L / SS316L), Duplex Stainless Steel (2507 / 1.4529), Bronze, DI/WCB/SS coated with Epoxy Painting / Nylon / EPDM / NBR / PTFE / PFA |
| Stem / Shaft | SS416, SS431, SS304, SS316, Duplex Stainless Steel, Monel |
| Seat | NBR, EPDM / REPDM, PTFE / RPTFE, Viton, Neoprene, Hypalon, Silicon, PFA |
| Bushing | PTFE, Bronze |
| O-Ring | NBR, EPDM, FKM |
| Actuator Options | Hand Lever, Gear Box, Electric Actuator, Pneumatic Actuator |
Key Design Features & Engineering Advantages
Tangential Disc Pin Design: The disc cone pin is positioned tangentially, half in the disc and half in the shaft, placing it in compression rather than shear, which completely eliminates the possibility of failure.
Self-Compensating Gland Bridge: The rocker-shaped gland bridge compensates for uneven adjustment of the gland nut, significantly reducing packing wear and preventing stem leakage.
Integral Cast Disc Stops: Integral cast disc position stops perfectly align the disc inside the seat, providing precise closing geometry and maximizing both seat and seal life.
Double Eccentric Sealing: The double eccentric configuration ensures that the disc detaches instantly from the seat during startup, eliminating uneven load, extending longevity, and providing superior resistance to high temperature, wear, and corrosion.
Industry Applications: Double eccentric butterfly valves (also recognized as high performance butterfly valves) are widely utilized in drainage systems for water plants, power plants, steel mills, chemical facilities, water source projects, and environmental protection infrastructure. They are particularly well-suited for water supply pipelines serving as reliable adjustment and shut-off equipment.
Operational Efficiency: Engineered with a compact profile and lightweight build for effortless installation and maintenance. Compared with centerline butterfly valves, double eccentric butterfly valves withstand higher pressure ratings, deliver extended service life, and ensure superior operational stability. For large diameters, they utilize lighter materials and reduce overall capital expenditure. (Note: Due to the presence of the central butterfly plate generating flow resistance, butterfly valves smaller than DN200 provide limited operational advantage.)
Frequently Asked Questions (FAQ)
1. What is a double eccentric butterfly valve and where is it applied?
Also known as a high performance butterfly valve, it is engineered primarily for water supply and drainage networks across water plants, power plants, steel mills, chemical facilities, environmental engineering, and water source projects as an effective regulation and shut-off solution.
2. How does the double eccentric structure improve valve sealing and service life?
The double offset geometry ensures that the valve disc rapidly disengages from the seat immediately upon opening. This design eliminates friction and uneven load on the sealing seat, prevents premature wear, enhances high-temperature and corrosion resistance, and significantly extends operational life.
3. What mechanical advantage does the tangential disc cone pin offer?
The cone pin is positioned tangentially, half embedded in the disc and half in the shaft. This configuration subjects the pin to compressive force rather than shear stress, eliminating pin shearing and the resulting risk of valve failure.
4. How does the rocker-shaped gland bridge prevent packing leakage?
The rocker-shaped gland bridge dynamically compensates for uneven tightening or adjustment of the gland nuts, maintaining uniform compression on the packing set and minimizing the risk of stem packing leakage.
5. How does a double eccentric butterfly valve compare to a concentric (centerline) valve?
Compared to concentric butterfly valves, double eccentric valves deliver superior pressure capabilities, enhanced stability, and longer working life. In larger pipe sizes, they provide a much lighter construction and lower investment cost compared to other industrial valve types.
6. Why are double eccentric butterfly valves not recommended for diameters below DN200?
Because the butterfly disc resides centrally within the flow passageway, it induces noticeable fluid resistance. In small pipe sizes under DN200, this flow resistance outweighs the operational benefits, making smaller sizes less practical compared to other valve designs.
