What’s the Difference Between Double Flange and Single Flange Butterfly Valves?

In industrial pipeline systems, butterfly valves are widely used in applications such as water supply and drainage, HVAC, fire protection, metallurgy, and chemical industries due to their compact structure, quick operation, and low flow resistance.

 

Among the various connection types, Double Flange Butterfly Valves and Single Flange Butterfly Valves are two common structural designs.

 

Many buyers are often confused during selection:

 

What’s the real difference between them?

 

Which one is better for my project?

 

What are their pros and cons?

 

This article gives you a comprehensive comparison of the two, helping you make a scientific choice and avoid engineering risks.

 

Basic Structure Overview

 

Double Flange Butterfly Valve

 

A double flange butterfly valve features standard flanges on both ends of the valve body, connected to the pipeline with bolts. It offers excellent stability and reliable sealing, commonly used in critical pipeline systems or where stringent installation conditions apply.

 

Key Features:

 

* Flanges on both sides of the valve body

 

* Disc rotates at the center to open/close the flow

 

* Ideal for large-diameter, high-pressure, or high-vibration systems

Single Flange Butterfly Valve

 

Single flange butterfly valves have only one flanged end, with the other end in wafer (lug) type design. They rely on bolts to clamp between the flanges of the pipeline. They are more compact and lighter, suitable for space-restricted or cost-sensitive installations.

 

Key Features:

 

* One flange, one wafer/lug-type end

 

* Suitable for small to medium diameter systems

 

* Often used in low-pressure or non-critical systems

Double Flange vs Single Flange – Performance Comparison

 

Comparison Item	Double Flange Butterfly Valve	Single Flange Butterfly Valve
Connection Method	Both ends have standard flanges	One end flange, one end clamped
Installation Strength	High, strong anti-vibration	Weaker, relies on clamping force
Maintenance	Easy to disassemble/replace	More complex, depends on pipe loosening
Sealing Performance	Excellent, larger sealing surface	Moderate, smaller sealing area
Applicable Size	Medium to large (DN200 and above)	Small to medium (DN50–DN300)
Weight & Cost	Heavier, slightly higher cost	Lighter, more cost-effective
Pressure Level	Suitable for PN10–PN40	Suitable for PN6–PN16

 

✅ Pros & Recommended Applications

 

Double Flange Butterfly Valve Advantages:

 

High Structural Stability: Ideal for pump outlets or main pipelines exposed to vibration

 

Superior Sealing: Suited for systems requiring high sealing integrity such as fire pipelines and industrial water supply

 

Easy Maintenance: Flanged connections make replacement and maintenance convenient

 

Resistant to Harsh Conditions: Performs well in abrasive, high-temp, or corrosive media

 

Recommended Use Cases:

 

* Municipal water supply systems

 

* Large-scale industrial cooling

 

* Main fire protection lines

 

* Chemical pipeline systems

 

* High-frequency operation systems

Single Flange Butterfly Valve Advantages:

 

Lightweight & Compact: Great for limited space installations

 

Lower Installation Cost: Simple design reduces labor cost

 

Lower Shipping Cost: Lightweight for bulk long-distance delivery

 

Fits Lightweight Piping: Like PVC or PE piping

 

Recommended Use Cases:

 

* Industrial water treatment systems

 

* HVAC networks

 

* Underground or confined spaces

 

* Agricultural irrigation

 

* OEM equipment assemblies

 

Selection Guide: How to Choose?

 

When selecting the right butterfly valve, consider the following factors:

 

Pipeline pressure & flow rate: Choose double flange for higher pressure

 

Frequency of maintenance: Double flange is easier to remove and service

 

Space constraints: Single flange suits narrow spaces

 

Budget and lead time: Single flange is quicker and cheaper

 

Vibration or pressure conditions: Use double flange under such conditions

 

Final Thoughts

 

Choosing the right type of butterfly valve is crucial for system performance and safety.

 

Misselection may lead to sealing failures or operational hazards. The core difference lies in their structural robustness and suitable applications. Make informed decisions based on pressure, installation space, maintenance needs, and system stability.

 

Still unsure? Our WEIZIDOM engineering team is here to help with professional selection support and customized product services.

 

FAQ – Frequently Asked Questions

 

1. What’s the difference between a double flange and single flange butterfly valve?

 

They differ in connection design, installation strength, sealing ability, and application range. Double flange is more robust, single flange is lighter.

 

2. Which valve is better for systems with vibration?

 

Double flange butterfly valve is recommended due to stronger structure.

 

3. Where can I use single flange butterfly valves?

 

Best for low-pressure, lightweight, or limited-space systems like HVAC and water treatment.

 

4. Which one has better sealing?

 

Double flange valves generally offer better sealing due to larger and more stable contact surfaces.

 

5. Is single flange easier to install?

 

Yes. Its lighter body and simple structure make it quicker and easier to install.

 

6. Does WEIZIDOM offer custom butterfly valve solutions?

 

Absolutely. We support customization by material, size, drive type, and provide full project selection services.