What Are The Different Types of Flanged Butterfly Valves?

There are three main types of flanged butterfly valves: concentric, double eccentric, and triple eccentric designs. These valves use a rotating disc to control fluid flow, plus feature flanged ends that connect directly to industrial pipe flanges. You’ll also find them as either soft seal or hard seal valves depending on how they create a tight closure.

Let’s take a closer look at each type to help you understand which might work best in your case.

Main Types of Butterfly Valve

Concentric Butterfly Valves

With concentric butterfly valves, you’ll notice the stem sits right at the disc’s center, and they both rotate on the same axis.

This straightforward design means you can get an economical solution for everyday applications where you don’t need extreme pressure handling.

They typically use rubber or similar resilient seats that create a good seal when you close the valve.

Double Eccentric Butterfly Valves

When you need something more robust, double eccentric valves offer two important offsets: the stem sits behind the disc centerline and away from the pipe’s centerline.

This clever design means you’ll see much less wear on sealing components and get better shutoff performance in demanding conditions.

For instance, if you check out Youfumi’s lined butterfly valves, you can see this advanced design with their removable dual-body structure and integrated valve stem and disc that prevents blowout during operation.

Triple Eccentric Butterfly Valves

If you’re handling truly demanding applications, triple eccentric valves add a third offset with conical sealing surfaces for exceptional performance.

This sophisticated engineering means you’ll experience virtually no friction during operation and get bubble-tight shutoff even in extreme environments.

Butterfly Valve Types by Connection

Beyond the disc design, flanged butterfly valves are also classified by their connection method. Here are the main types:

Wafer-Style Butterfly Valves 

These valves fit between pipe flanges and use the same bolts that connect the flanges. 

You’ll appreciate their economical design and space-saving profile, perfect for standard applications. 

They’re lightweight and easy to install but aren’t suitable for end-of-line service without additional support.

Lug-Type Butterfly Valves 

Featuring threaded inserts for direct bolting to pipe flanges, these valves allow removal of one side of piping while maintaining pressure. 

This design is ideal when you need to perform maintenance without shutting down your entire system. 

Youfumi’s lined butterfly valves are available in lug configuration, combining their advanced sealing technology with this practical connection type.

Double-Flanged Butterfly Valves 

With raised faces on both sides that bolt directly to pipe flanges, these valves provide maximum stability. 

They’re the preferred choice for high-pressure applications where performance reliability is non-negotiable. 

Youfumi offers these robust double-flanged options with their integrated valve stem and disc design that prevents blowout even in demanding conditions.

Additional Connection Options

Depending on your application, you might also consider clamp connections for sanitary environments or welded connections for permanent installation. 

Youfumi provides various connection options including clamp and U-shaped configurations, all complying with ISO5211 standards for perfect integration with your existing systems.

Sealing Classifications of Flanged Butterfly Valves

Soft Seal Butterfly Valves

When you use soft seal valves, you’re getting resilient materials like rubber, PTFE, or other elastomers that create tight seals against the disc.

You can achieve exceptional leakage prevention (up to Class VI per FCI 70-2:2006 standards), but you’ll find they have limitations in high-temperature applications.

If you’re looking for quality options, Youfumi offers lined butterfly valves with multiple safety seals that won’t pollute the environment and meet FDA standards

Hard Seal Butterfly Valves

On the other hand, if you choose hard seal designs, you’ll get metal-to-metal, metal-to-fluoroplastic, or multi-layer composite plates for sealing.

While you can use these in higher temperatures and pressures than soft seal valves, you won’t get quite the same level of tight shutoff performance.

These valves make sense when you need durability in extreme conditions more than perfect sealing, such as in high-temperature industrial processes.

Selection Criteria

When choosing a flanged butterfly valve, matching your application needs with the right valve features ensures optimal performance. The selection matrix below will help guide your decision:

Your specific operating conditions will determine which combination of features will provide the optimal performance and value for your system.

Conclusion

Those are the main butterfly valve types to help you choose the right one for your industrial needs.

When selecting a valve, consider pressure requirements, temperature range, media type, and installation space.

Youfumi has manufactured quality lined valves since 1989. Our butterfly valves feature FDA-compliant materials and ISO5211 platforms, serving customers in over 60 countries.Need help choosing? Contact our team for expert assistance with your specific requirements