What Is a Concentric Butterfly Valve?

What Is a Concentric Butterfly Valve?

A concentric butterfly valve is a type of quarter-turn valve in which the stem and disc are centered within the valve body. The sealing surface is typically made of a soft elastomer seat, allowing for tight shutoff even under low pressure. Because of its straightforward structure, the valve is lightweight, easy to install, and suitable for large-diameter piping systems.

Key Characteristics

• The stem passes through the center of the disc.
• The disc sits in the center of the flow path.
• The valve utilizes a resilient rubber seat for sealing.
• Ideal for low- to medium-pressure applications.

How Does a Concentric Butterfly Valve Work?

The operation of a concentric butterfly valve is simple and efficient. The valve disc rotates 90 degrees to open or close the flow:

• Open Position: The disc turns parallel to the flow direction, allowing fluid to pass with minimal resistance.
• Closed Position: The disc rotates perpendicular to the flow, pressing tightly against the soft seat to form a bubble-tight seal.

Because only a quarter-turn is required, the valve offers rapid operation and can be easily automated using electric, pneumatic, or hydraulic actuators.

Design Features of Concentric Butterfly Valves

1. Resilient Seat for Bubble-Tight Sealing

The soft elastomer seat—commonly EPDM, NBR, or PTFE—provides excellent sealing performance and resistance to wear, corrosion, and leakage.

2. Lightweight Construction

Compared with gate valves and ball valves, concentric butterfly valves have fewer components, making them lighter and more cost-effective for large diameters.

3. Low Torque Requirement

The central alignment of the disc and stem reduces friction during operation, resulting in lower torque and smaller actuator selection.

4. Versatile Material Options

• Body: Cast iron, ductile iron, stainless steel
• Disc: Stainless steel, nickel-plated, aluminum bronze
• Seat: EPDM, NBR, PTFE, Viton

Material combinations can be customized based on the fluid characteristics and operating conditions.

5. Easy Installation and Maintenance

Its compact design allows for installation in tight spaces, and the replaceable seat design reduces long-term maintenance costs.

Advantages of Concentric Butterfly Valves

• Cost-effective solution for general industrial flow control
• Excellent shutoff capability due to the soft seat
• Quick quarter-turn operation
• Suitable for large pipe diameters
• Low-pressure drop in the fully open position
• Compatible with multiple actuation methods

Common Applications of Concentric Butterfly Valves

1. Water and Wastewater Treatment

For clean water, raw water, and sewage pipelines, concentric butterfly valves provide reliable flow isolation and regulation.

2. HVAC Systems

Used extensively in chilled water, cooling towers, and air-conditioning systems due to their reliability and low operating torque.

3. Chemical and Petrochemical Processing

With corrosion-resistant materials, they can handle a variety of chemical fluids safely.

4. Food and Beverage Industry

PTFE-lined and stainless-steel models ensure hygiene and compatibility with food-grade requirements.

5. Fire Protection Systems

UL/FM-approved concentric butterfly valves are widely used in fire-suppression pipelines, thanks to rapid operation and dependable sealing.

Selection Guide for Concentric Butterfly Valves

When choosing a concentric butterfly valve, consider the following factors:

1. Valve Size and Pressure Rating
   Ensure compatibility with the pipeline and system pressure.
2. Seat and Disc Materials
   Select based on fluid type, temperature, and corrosion resistance.
3. End Connection Type
   • Wafer
   • Lug
   • Flanged
4. Actuation Method
   • Manual (lever or gearbox)
   • Pneumatic actuator
   • Electric actuator
   • Hydraulic actuator
5. Industry Standards and Certifications
   Look for compliance with ISO, API, AWWA, and other industry standards.

Why Choose Concentric Butterfly Valves?

A concentric butterfly valve is an ideal choice for systems requiring reliable shutoff, cost efficiency, and simple operation. Its design provides superior sealing performance and versatility across a wide range of industrial applications. Whether used for water distribution, chemical processing, or HVAC systems, the concentric butterfly valve delivers strong performance with minimal maintenance.