Double eccentric butterfly valves, also known as high-performance butterfly valves, are designed with two offsets to enhance performance and improve sealing capabilities. These valves are widely used in various industries for applications that require reliable shut-off, control, and versatility. Here are key features and characteristics of double eccentric butterfly valves:
- Double Eccentric Design:
- First Offset (Eccentricity): The shaft is positioned off-center from the center of the valve body, creating the first offset. This offset allows the disc to move away from the valve seat with minimal friction during operation, reducing wear and improving sealing.
- Second Offset (Concentricity): The center of the disc is offset from the centerline of the valve body, creating the second eccentricity. This offset helps achieve a more precise sealing contact during closure, reducing the wear on the valve seat.
- Metal or Soft Seated Options:
- Double eccentric butterfly valves can be equipped with either metal or soft seats. Metal seats are suitable for high-temperature and high-pressure applications, while soft seats made of materials like PTFE or elastomers provide tight shut-off.
- High-Performance Sealing:
- The double eccentric design significantly improves the valve’s sealing capabilities compared to a concentric butterfly valve. This feature is particularly beneficial for applications where a tight shut-off is crucial.
- Bi-Directional Sealing:
- Double eccentric butterfly valves are designed for bi-directional sealing, meaning they can provide a tight seal regardless of the flow direction.
- Low Friction Operation:
- The double eccentric design reduces friction during valve operation, resulting in lower torque requirements and extended service life.
- High-Pressure and High-Temperature Applications:
- These valves are suitable for applications with high-pressure and high-temperature requirements, making them versatile for use in industries such as oil and gas, chemical processing, water treatment, and more.
- Wafer, Lug, or Flanged End Connections:
- Double eccentric butterfly valves are available with various end connections, including wafer, lug, and flanged designs, allowing for easy integration into different piping systems.
- Fire-Safe Design:
- Some double eccentric butterfly valves are designed to meet fire-safe requirements, ensuring they maintain their integrity in the presence of fire.
- Actuation:
- Double eccentric butterfly valves can be operated manually or automated with electric or pneumatic actuators for remote control and precise flow regulation.
- Versatility:
- These valves are versatile and find application in various fluid-handling systems, including those involving water, air, gas, and a range of process fluids.
- Ease of Installation and Maintenance:
- Double eccentric butterfly valves are generally easy to install and maintain due to their simple design and fewer components compared to other types of valves.
Double eccentric butterfly valves are selected for applications where high-performance sealing, low friction, and reliability are essential. The specific choice of materials, end connections, and actuation methods depends on the requirements of the application and the characteristics of the fluid being handled. Proper installation and regular maintenance contribute to the efficient and reliable performance of double eccentric butterfly valves in industrial processes.