A Complete Buyer’s Guide to Double Eccentric Butterfly Valves

Double Eccentric Butterfly Valve: What It Is, How It Works, and Where to Use It

When it comes to efficient and reliable flow control, butterfly valves are among the most widely used solutions in water treatment, oil & gas, and industrial applications. Among them, the double eccentric butterfly valve (also known as the double offset butterfly valve) has gained popularity due to its unique design and superior sealing performance compared to conventional butterfly valves.

 

This article explains what a double eccentric butterfly valve is, how it works, its advantages, and the industries where it is most commonly used. If you are searching for a valve that balances performance, cost, and durability, this guide will help you understand whether a double eccentric butterfly valve is the right choice for your project.

 

What is a Double Eccentric Butterfly Valve?

 

A double eccentric butterfly valve is a type of butterfly valve designed with two offsets (eccentricities) between the disc and the valve body/shaft.

 

The Two Offsets Explained:

First Offset: The shaft is placed slightly behind the centerline of the sealing surface.

Second Offset: The shaft is positioned slightly off the centerline of the pipe.

 

This design minimizes friction between the disc and the seat during opening and closing, extending the valve’s lifespan and improving sealing.

 

Key Characteristics:

Available in ductile iron, carbon steel, and stainless steel

 

Suitable for medium to high-pressure applications

 

Provides bi-directional sealing

 

Compact design with lightweight structure compared to gate valves

 

How Does a Double Eccentric Butterfly Valve Work?

 

Unlike a concentric (zero offset) butterfly valve, the double eccentric design allows the disc to move away from the seat quickly as the valve opens.

 

Working Mechanism:

 

When the valve closes, the disc moves into the seat at a slight angle, creating a tight and uniform seal.

 

When it opens, the disc immediately disengages from the seat, reducing wear and operating torque.

 

This makes the valve particularly effective for applications requiring frequent operation and long-term reliability.

 

Advantages of Double Eccentric Butterfly Valves

 

✅ Extended Service Life

 

Reduced friction during operation prevents seat wear, increasing valve longevity.

 

✅ Superior Sealing

 

Provides tight shut-off even under high pressure, making it reliable in critical water systems.

 

✅ Cost-Effective Alternative

 

Compared to gate valves or ball valves, it offers a balance of lower cost and reliable performance.

 

✅ Wide Size Range

 

Available in large diameters, making it suitable for municipal water supply networks and industrial pipelines.

 

✅  Lightweight and Space-Saving

 

Requires less installation space and is lighter than most gate valves, reducing construction and maintenance costs.

 

Where Are Double Eccentric Butterfly Valves Used?

 

✅ Water Supply and Distribution

 

Municipal drinking water pipelines

 

Irrigation systems

 

Pumping stations

 

✅ Wastewater Treatment

 

Effluent pipelines

 

Sludge and slurry management

 

Sewage treatment plants

 

✅ Industrial Applications

 

Power plants (cooling water systems)

 

Chemical and petrochemical industries

 

Oil & gas distribution pipelines
  

✅ Fire Protection Systems

 

Used in large-diameter fire main lines

 

Ensures quick shut-off in emergency conditions

 

Double Eccentric vs Triple Eccentric Butterfly Valves

 

Many buyers often compare double eccentric with triple eccentric butterfly valves.

 

Double Eccentric: Best for general water and industrial applications, cost-effective, reliable.

 

Triple Eccentric: Designed for very high pressure and temperature applications, with a conical sealing system, but generally more expensive.

 

✅ If your project requires tight sealing for water or wastewater systems, a double eccentric valve is the practical and economical choice.

 

Common Standards and Materials

 

Standards: AWWA C504, EN 593, API 609

 

Materials:

 

Body: Ductile iron, cast steel, stainless steel

 

Disc: Stainless steel, ductile iron with epoxy coating

  

Seat: EPDM, NBR, or metal seated options

  

Cost and Maintenance Considerations

 

Lower Operating Costs: Less torque required, smaller actuators can be used

 

Reduced Maintenance: Minimal seat wear and easy replacement when required

 

Total Lifecycle Cost Advantage: Compared to gate valves, double eccentric butterfly valves offer significant savings in large-diameter projects

 

Buyer’s Checklist: Is a Double Eccentric Butterfly Valve Right for You?

 

✅ Choose a double eccentric butterfly valve if:

 

You need reliable shut-off in water distribution or treatment plants

 

Your pipeline requires large-diameter valves

 

You want a cost-effective solution compared to gate or ball valves

 

You prefer low maintenance and long service life

 

❌ Avoid if:

 

Your system requires operation in extremely high temperature or pressure (consider triple eccentric valves instead).

 

The double eccentric butterfly valve is a versatile, cost-effective, and reliable solution for a wide range of water, wastewater, and industrial applications. Its unique design reduces wear, improves sealing, and extends service life, making it a preferred choice for engineers and project owners worldwide.

 

At WEIZIDOM, we manufacture and supply high-quality double eccentric butterfly valves in ductile iron, carbon steel, and stainless steel. With over 100+ export countries, 1000+ project experiences, and 5+ factories, we provide solutions that ensure performance, durability, and value.

 

✅ Contact us today at eileen@wsdsolution.com for product catalogs and quotations.

 

✅ Visit: www.wsdsolution.com