Double Eccentric Butterfly Valve

Double Eccentric Butterfly Valve

A double eccentric butterfly valve is a type of valve used to control the flow of a fluid in a pipeline. It consists of a circular disc with a shaft running through the center of the disc. The disc is positioned perpendicular to the pipeline and rotates around the shaft to regulate the flow of the fluid.

The double eccentric design of this valve means that the disc is offset from the centerline of the pipeline, and the shaft is also offset from the centerline of the disc. This configuration allows the disc to move away from the seat without rubbing against it, which reduces wear and tear on the valve and improves its sealing capabilities.

Double eccentric butterfly valves are commonly used in applications where tight shut-off is required, such as in the oil and gas industry, water treatment, and power generation. They are also used in HVAC systems and other applications where precise flow control is necessary.

What is double eccentric butterfly valve?

Double eccentric butterfly valves are most often used in water supply applications below ground as an alternative to gate valves. When installing butterfly valves below ground a lower bury depth is required and typically, they are more cost-effective, especially in the large dimensions, compared to gate valves.

Operational Principle:

The double eccentric butterfly valve operates on the principle of a disc rotating around an axis that is offset from the center of the valve's body. The valve has a disc or plate that is positioned in the center of the pipe or duct and is connected to a stem that passes through the valve's body. When the stem is turned, the disc rotates around its axis, which allows for the control of the fluid or gas flow through the valve.

The double eccentric design of the valve means that the disc is positioned off-center from the valve's body and the stem's axis. This design creates an offset angle between the stem's axis and the disc's rotation axis. As the disc rotates, it moves away from the valve's body and opens the valve, allowing the fluid or gas to pass through. As the disc rotates back towards the valve's body, it moves towards the closed position and reduces the flow.

The double eccentric design also allows for the disc to lift off the valve's seat before it begins to rotate, reducing friction and wear on the valve's sealing components. This design feature helps to improve the valve's reliability and extend its service life. Additionally, the valve can be designed with a soft-seated or metal-seated option, depending on the specific application requirements.

Advantage:

Reasonable design, compact structure, easy assembly and disassembly, and easy maintenance.

2. The eccentric structure is adopted to reduce the friction of the sealing ring and prolong the service life of the valve.

3. Completely sealed, zero leakage. Can be used in ultra-high vacuum conditions

4. Replace the valve plate sealing ring, butterfly plate, shaft and other materials, which can be applied to a variety of media and different temperature.

5. Suitable for high flow rate applications

6. Blowout-proof shaft design with replaceable O-ring shaft seal and self-lubricating bronze/Teflon radial bearings

7. Flap seals are made of potable water approved EPDM rubber that has excellent compression permanent deformation so it can recover its original shape

8. Low operating torque.

Where are double eccentric butterfly valves used?

Double eccentric butterfly valves are most often used in water supply applications below ground as an alternative to gate valves. When installing butterfly valves below ground a lower bury depth is required and typically, they are more cost-effective, especially in the large dimensions, compared to gate valves. They can of course also be used above ground.

Specification