High-Performance Butterfly Valves | EATHU Industrial Valve Supplier
What Is a Butterfly Valve and How Does It Work?
A butterfly valve is a type of quarter-turn valve that uses a rotating disc (valve plate) to regulate flow. The disc rotates around a shaft within the valve seat, and the angle of rotation determines the degree of valve opening or closing.
Butterfly Valve Structure
A standard butterfly valve consists of the valve body, disc, valve stem, bearings, sealing elements, actuator, and auxiliary components. This compact design ensures quick opening/closing and minimal space requirements.
Working Principle of Butterfly Valves
Butterfly valves function by turning the valve stem, which drives the disc to rotate. Inside the cylindrical passage of the valve body, the disc rotates 90 degrees to control flow. When fully opened at 90°, the disc is parallel to the flow, offering minimal resistance. Intermediate positions allow flow regulation. A gearbox or worm gear operator can be added for precise control and self-locking capability, improving both flow regulation and operational performance.
Key Features of Butterfly Valves
Low Flow Resistance when fully open. Between 15°–70° opening, butterfly valves offer sensitive flow control, ideal for large-diameter pipelines. The disc's wiping motion makes it suitable for media containing suspended solids, and, depending on sealing materials, for powdered or granular media as well.
Ideal for Flow Regulation. Due to higher pressure loss (approx. 3 times more than gate valves), careful consideration of pressure drop and sealing pressure strength is necessary when selecting butterfly valves. Also, note the temperature limits of soft seats in high-temperature applications.
Compact Dimensions and fast operation speed. The design is ideal for large-diameter applications. Proper sizing and type selection are crucial for achieving efficient flow control.
Types of Butterfly Valves
1. Concentric Butterfly Valve (Lined Type)
The stem, disc center, and body centerline are all aligned.
Simple structure and easy manufacturing.
Commonly used with rubber-lined or PTFE-lined seats, making it ideal for corrosive media.
Drawback: constant scraping between disc and seat causes higher wear; not suitable for high temperatures due to soft sealing materials.
2. Single Offset Butterfly Valve
The stem is offset from the disc center, reducing direct compression between disc and seat.
Minimizes wear compared to concentric designs.
Still experiences scraping during operation, making it less commonly used.
Key Features:
Suitable for soft sealing applications.
Sealing is unidirectional and based on interference fit.
Less suitable for metal-to-metal sealing due to potential seal damage.
3. Double Offset Butterfly Valve
Most widely used design in industrial applications.
The disc shaft is offset from both the disc center and the body centerline.
When opened, the disc quickly disengages from the seat, significantly reducing friction and wear.
Enables the use of metal seats for high-temperature applications.
Seal Mechanism:
Relies on position sealing, where line contact and elastic deformation provide sealing.
Requires precise closing alignment.
Pressure resistance is generally lower than other valve types.
4. Triple Offset Butterfly Valve
Designed for zero leakage and high-temperature, high-pressure service.
Uses a torque-sealing mechanism, where sealing is achieved by the contact surface pressure, not elastic deformation.
The disc seal surface is conical and eccentrically aligned, ensuring non-frictional closing.
Key Advantages:
Suitable for critical applications like natural gas pipelines, steam systems, and high-demand process control.
Combines metal seat durability with excellent sealing performance.
Butterfly Valve Maintenance Tips
Check sealing performance regularly. Leakage can affect media transport and pose safety risks.
For soft-seal butterfly valves, monitor seal aging and replace as needed.
Keep the valve stem lubricated to reduce friction and wear, ensuring smooth operation.
Inspect the disc for erosion or corrosion, especially in systems handling abrasive or corrosive media.
Installation Guidelines for Butterfly Valves
Ensure the installation direction matches the media flow.
Maintain appropriate height for easy access and maintenance.
For large or heavy butterfly valves, a solid base is required to avoid operational misalignment or damage.
Perform a pre-installation inspection for damage or missing parts.
Clean internal pipelines to prevent debris from affecting valve function.
During installation, whether flanged or wafer type, tighten bolts evenly to prevent leakage.
Recommended Butterfly Valves by EATHU
As a trusted name in the industrial valve manufacturing industry, EATHU offers a full range of high-performance butterfly valves tailored for various industrial applications:
✔ Concentric Butterfly Valves
Precision-engineered with high-quality materials.
Lined with durable rubber for excellent sealing and abrasion resistance.
Ideal for chemical, food-grade, and corrosion-sensitive applications.
✔ Single Offset Butterfly Valves
Smart design to reduce excess compression on the seat.
Extended lifespan in demanding environments like power plant cooling water systems.
✔ Double Offset Butterfly Valves
EATHU's flagship product.
Delivers superior performance with minimal wear and leakage.
Handles high-pressure, high-temperature conditions reliably in petrochemical and refinery operations.
✔ Triple Offset Butterfly Valves
Advanced metal-seated valves designed for zero leakage.
Torque-based sealing mechanism ensures exceptional sealing at extreme temperatures and pressures.
Perfect for natural gas, steam lines, and high-stakes industrial systems.