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Ductile Iron/WCB Double Offset Butterfly Valve - China Factory Suppliers, 2 to 24 Size Range, Bi-Directional Zero Leakage
Product Details
Our Double Offset Butterfly Valve combines robust engineering with high‑performance sealing technology to deliver superior flow control and reliable shut‑off in demanding industrial applications.
Featuring a dual-offset shaft design, this valve minimizes seat friction during operation, ensuring tight sealing performance, reduced torque, and extended durability compared to concentric butterfly valves.
A double offset butterfly valve incorporates two key design offsets:
1
First Offset – The shaft is positioned behind the centerline of the sealing surface.
2
Second Offset – The shaft is offset from the centerline of the pipe and valve body.
This dual-offset configuration allows the disc to disengage from the seat immediately upon opening, reducing wear and eliminating unnecessary friction. The result is improved sealing integrity, lower operating torque, and longer service life.
Key Features
⚙️
Advanced Double Offset Geometry
The disc shaft is offset from both the seal surface and the pipeline centerline. This double eccentric arrangement eliminates continuous sliding contact between the disc and seat, reducing wear and torque and extending service life.
🔒
Bubble Tight Shutoff & Zero Leakage
With precision engineered sealing surfaces and premium seat materials (e.g., PTFE, EPDM, metal seated options), the valve achieves bubble tight shutoff (Class VI) in standard configurations, ensuring reliable isolation in safety critical systems.
Specification
Materials
| Parts | Materials |
|---|---|
| Body | Cast Iron |
| Bushing | PTFE |
| O Ring | EPDM |
| Shaft | Stainless Steel |
| Disc | Stainless Steel |
| Seat | EPDM |
| Pin | Stainless Steel |
Dimensions
| DN | NPS | A | B | C | L | A | B | C |
|---|---|---|---|---|---|---|---|---|
| 50 | 2'' | 165 | 125 | 99 | 108 | 165 | 125 | 99 |
| 65 | 2-1/2'' | 185 | 145 | 118 | 112 | 185 | 145 | 118 |
| 80 | 3'' | 200 | 160 | 132 | 114 | 200 | 160 | 132 |
| 100 | 4'' | 220 | 180 | 156 | 127 | 220 | 180 | 156 |
| 125 | 5'' | 250 | 210 | 184 | 140 | 250 | 210 | 184 |
| 150 | 6'' | 285 | 240 | 211 | 140 | 285 | 240 | 211 |
| 200 | 8'' | 340 | 295 | 266 | 152 | 340 | 295 | 266 |
| 250 | 10'' | 395 | 350 | 319 | 165 | 405 | 355 | 319 |
| 300 | 12'' | 445 | 400 | 370 | 178 | 460 | 410 | 370 |
| 350 | 14'' | 505 | 460 | 429 | 190 | 520 | 470 | 429 |
| 400 | 16'' | 565 | 515 | 480 | 216 | 580 | 525 | 480 |
| 450 | 18'' | 615 | 565 | 530 | 222 | 640 | 585 | 548 |
| 500 | 20'' | 670 | 620 | 582 | 229 | 715 | 650 | 609 |
| 600 | 24'' | 780 | 725 | 682 | 267 | 840 | 770 | 720 |
| 700 | 28'' | 895 | 840 | 794 | 292 | 910 | 840 | 794 |
| 800 | 32'' | 1015 | 950 | 901 | 318 | 1025 | 950 | 901 |
| 900 | 36'' | 1115 | 1050 | 1001 | 330 | 1125 | 1050 | 1001 |
| 1000 | 40'' | 1230 | 1160 | 1112 | 410 | 1255 | 1170 | 1112 |
| 1200 | 48'' | 1455 | 1380 | 1328 | 470 | 1485 | 1390 | 1328 |
| 1400 | 56'' | 1675 | 1590 | 1530 | 530 | 1685 | 1590 | 1530 |
| 1600 | 64'' | 1915 | 1820 | 1750 | 600 | 1930 | 1820 | 1750 |
| 1800 | 72'' | 2115 | 2020 | 1950 | 670 | 2130 | 2020 | 1950 |
| 2000 | 80'' | 2325 | 2230 | 2150 | 760 | 2345 | 2230 | 2150 |
| 2200 | 88'' | 2550 | 2440 | 2295 | 800 | 2550 | 2440 | 2295 |
| 2400 | 96'' | 2760 | 2650 | 2495 | 850 | 2760 | 2650 | 2495 |
Frequently Asked Questions
Q
What is a double offset butterfly valve and how does it differ from a concentric butterfly valve?
A double offset butterfly valve features two shaft offsets — one behind the sealing surface centerline and one from the pipe centerline — allowing the disc to lift away from the seat immediately upon opening. This eliminates continuous sliding contact, significantly reducing wear and operating torque compared to a standard concentric butterfly valve where the disc remains in constant contact with the seat throughout the full stroke.
Q
What seat materials are available for the double offset butterfly valve?
The valve is available with multiple seat material options including EPDM (standard), PTFE, and metal seated configurations. The choice of seat material depends on the media type, operating temperature, and pressure requirements of your application.
Q
What leakage class does this double offset butterfly valve achieve?
In standard configurations with soft seat materials such as EPDM or PTFE, the double offset butterfly valve achieves bubble-tight shutoff rated at Class VI per ANSI/FCI 70-2. This makes it suitable for safety-critical isolation applications where zero leakage is required.
Q
What size range is the double offset butterfly valve available in?
The double offset butterfly valve is available in a wide size range from DN50 (2 inches NPS) up to DN2400 (96 inches NPS), covering virtually all industrial pipeline requirements from small-bore process lines to large-diameter water and industrial fluid systems.
Q
What are the main body and disc materials used in this valve?
The standard valve body is manufactured from cast iron, offering a cost-effective solution for general industrial applications. The disc, shaft, and pin are made from stainless steel for corrosion resistance and strength. PTFE bushings and EPDM O-rings and seat provide reliable sealing performance across a wide range of media.
Q
What are the typical applications for a double offset butterfly valve?
Double offset butterfly valves are widely used in water treatment and distribution, HVAC systems, fire protection pipelines, industrial process plants, power generation, chemical processing, and oil & gas facilities. Their combination of tight shutoff, low torque operation, and long service life makes them ideal for both on/off isolation and throttling duties.
Product Packaging
01020304