Views: 0 Author: J-VALVES Publish Time: 2025-03-21 Origin: Site
Understanding Butterfly Valves
Butterfly valves are quarter-turn valves that use a circular disc to control fluid flow. The disc rotates around a central shaft, allowing for quick and efficient control of fluid flow. Butterfly valves are known for their compact size, lightweight design, and ability to provide tight sealing with minimal pressure drop.
• Valve Body: The main structure that houses the disc and other components.
• Disc: The circular component that controls fluid flow by rotating around the shaft.• Shaft: The central component around which the disc rotates.
• Seat: The sealing surface that ensures a tight seal when the valve is closed.
• Actuator: The mechanism used to rotate the disc, which can be manual, electric, pneumatic, or hydraulic.
Midline butterfly valves, also known as concentric butterfly valves, have a simple and straightforward design. The disc is mounted concentrically on the shaft, which means the disc and shaft share the same center. This design allows for a relatively simple and cost-effective construction.
• Concentric Disc and Shaft: The disc is mounted concentrically on the shaft, ensuring a uniform sealing surface.
• Rubber or PTFE Seat: The seat is typically made of rubber or PTFE, providing good sealing properties.
• Quarter-Turn Operation: The valve operates with a quarter-turn, allowing for quick opening and closing.
• Compact Design: Midline butterfly valves are compact and lightweight, making them suitable for space-constrained applications.
Midline butterfly valves are ideal for applications where cost-effectiveness and simplicity are priorities. They are commonly used in:
• Water Treatment: For controlling water flow in municipal water supply systems and wastewater treatment plants.
• HVAC Systems: In heating, ventilation, and air conditioning systems for controlling air and water flow.
• Food and Beverage Industry: For controlling the flow of food-grade liquids and gases.
Double Eccentric Butterfly Valves
Double eccentric butterfly valves, also known as double offset butterfly valves, have a more complex design compared to midline butterfly valves. The disc is offset from the shaft in two directions: laterally and axially. This design reduces the contact area between the disc and the seat, resulting in lower operating torque and improved sealing performance.
• Double Offset Design: The disc is offset from the shaft in two directions, reducing the contact area and improving sealing.
• Metal Seat: The seat is typically made of metal, providing enhanced durability and resistance to wear.
• Quarter-Turn Operation: Like midline butterfly valves, double eccentric butterfly valves operate with a quarter-turn.
• High-Performance Sealing: The design allows for better sealing performance, even under high-pressure conditions.
Double eccentric butterfly valves are suitable for applications requiring higher performance and reliability. They are commonly used in:
• Oil and Gas Industry: For controlling the flow of hydrocarbons in pipelines and processing plants.
• Chemical Processing: In chemical plants where high-pressure and high-temperature fluids need to be controlled.
• Power Generation: For controlling steam and cooling water in power plants.
| Feature | Midline Butterfly Valves | Double Eccentric Butterfly Valves |
| Sealing Material | Rubber or PTFE | Metal |
| Sealing Performance | Good, suitable for lower pressure applications | Excellent, suitable for high-pressure applications |
| Leakage Rate | Higher leakage rate compared to double eccentric valves | Lower leakage rate, providing better sealing |
| Feature | Midline Butterfly Valves | Double Eccentric Butterfly Valves |
| Torque Requirement | Higher torque required, especially in larger sizes | Lower torque required due to the double offset design |
| Ease of Operation | May require more effort to operate | Easier to operate, especially in larger sizes |
Pressure and Temperature Range
| Feature | Midline Butterfly Valves | Double Eccentric Butterfly Valves |
| Pressure Range | Lower pressure applications | Higher pressure applications |
| Temperature Range | Lower temperature applications | Higher temperature applications |
