Concentric vs Eccentric Butterfly Valve: Key Differences 

Butterfly valves form an integral component of fluid control systems, very much sought after for taking up less space, requiring less maintenance, and having rapid operation. But then, not all butterfly valves are created equal. Among the numerous kinds, concentric and eccentric butterfly valves stand out due to their unique designs and advantages depending on application. 

Understanding the concentric and eccentric butterfly valves is crucial when deciding on the ideal valve for your system. Valvesonly Europe elaborates in detail on both types—describing their design, function, advantage, and favourable applications. 

What is a Concentric Butterfly Valve? 

The simplest of them all is a concentric butterfly valve, or a zero-offset butterfly valve. Stem and disc are on the same axis in such a valve and seat completely envelopes the disc. 

• Same centreline as disc and stem. 

• Disc is rotated in a flexible seat. 

• Used commonly in low-temperature and low-pressure systems. 

Disk in a concentric valve rotates 90 degrees to allow or shut off flow. Because of its centre-to-centre design, the valve is constantly in contact with the seat when closing and opening and therefore useful in use with water, air, and other non-abrasive liquids. 

What is a Eccentric Butterfly Valve? 

An offset eccentric butterfly valve is offset between the disc and stem. This minimizes the friction of the disc on the seat during operation. There are two general types of eccentric valves: double-offset (double eccentric) and triple-offset (triple eccentric). 

Main Features: 

• Disc offset from body centreline and stem centreline. 

• Minimizes wear by minimizing seat contact during rotation. 

• Best suited for high-pressure, high-temperature, and critical processes. 

• The triple-offset valve has a secondary seal with a metal seat as well, making it steam, chemical, and gas-proof. 

Functions of Butterfly Valve: 

Concentric and eccentric butterfly valves have fundamental functions in common: 

• Start and stop flow 

• Regulate flow (throttling) 

• Function as a check valve in certain designs 

• Isolate fluid in pipelines 

• Work under high or low pressure and temperature 

Important Differences Between Concentric and Eccentric Butterfly Valves 

Let us learn about the technical and functional differences that distinguish these two valves from one another. 

1. Design and Construction 

Concentric Valve: 

• Single-axis positioning of the stem and disc. 

• Rubber or elastomeric seat completely surrounds the disc. 

• Fewer components and simpler design. 

Eccentric Valve: 

• Disc is eccentric to the stem (single, double, or triple eccentric). 

• Seat can be composite or metal for longer service life. 

• More complex design to obtain good seal. 

Conclusion: Eccentric valves are more complex in design, thus improved performance at harsh environments. 

2. Disc-to-Seat Contact 

Concentric Valve: 

• Disc is in continuous contact with seat while operating. 

• This is accountable for long-term wear, especially with fluid abrasives. 

Eccentric Valve: 

• Disc recedes from seat while operating, reducing friction. 

• Less wear, better performance. 

Conclusion: Eccentric valves are more durable and withstand longer life under lesser contact. 

3. Pressure and Temperature Control 

Concentric Valve: 

• Limited to low-pressure, low-temperature duties. 

• Well-fitted to low-temperature process, ventilation, and chilled water. 

Eccentric Valve 

• Built for a medium to higher pressure and temperature. 

• Triple offset types can survive harsh service conditions. 

Conclusion: Eccentric valves give greater performance in worse and harsh services. 

4. Sealing Type and Tightness 

Concentric Valve: 

• Uses soft seats (EPDM, PTFE) for tight sealing. 

• Prone to seat deformation with time. 

Eccentric Valve: 

• Can use metal seats for fire-safe and high-pressure sealing. 

• Triple-offset types offer bubble-tight, bidirectional sealing. 

Conclusion: Eccentric valves offer stronger, tighter, and fire-safe sealing. 

5. Cost and Maintenance 

Concentric Valve: 

• Low cost and easy installation. 

• Lower initial cost and maintenance. 

Eccentric Valve: 

• Higher initial cost due to precision components. 

• Needs expert installation and regular seat replacement (especially in triple-offset). 

Conclusion: Concentric valves are economical for regular use, while eccentric valves are long-term beneficial in high-demand systems. 

6. Applications 

Concentric Butterfly Valve – Applied on: 

1. HVAC systems 

2. Portable water distribution 

3. General pipeline isolation 

Eccentric Butterfly Valve – Applied on: 

1. Oil and gas pipelines 

2. Chemical processing 

3. High-pressure steam systems 

4. Fire-safe and emergency shut-off 

Advantages: 

Concentric Butterfly Valve Advantages: 

• Simple design 

• Low cost 

• Easy to install 

• Successful in low-pressure application 

Eccentric Butterfly Valve Benefits: 

• Minimum seat wear 

• Good sealing in harsh conditions 

• Suited for fire-safe and high-performance systems 

Why Choose Valvesonly Europe? 

At Valvesonly Europe, we offer premium industrial valves with international performance standards. Our concentric and eccentric butterfly valves are precision-made and tested for endurance, leak-tightness, and efficiency. 

What Sets Us Apart: 

• Valves manufactured in Europe with solid certifications 

• Tailor-made solutions according to your project requirements 

• Global shipping with effective logistics support 

• After-sales technical support for each product 

• Competitive prices without compromising quality 

It will depend on what your system demands. If you work in low-pressure applications and wish to save money, concentric valves are for you. If you work in heavy-duty applications, requiring strength, accuracy, and high performance, eccentric valves are for you. 

We manufacture a wide variety of concentric and eccentric butterfly valves to international standards at Valvesonly Europe. Our valves are rigorously quality tested, efficient, and dependable for smooth operation across industries. 

Having trouble choosing the right type of valve? Call our valve specialists today for a tailored recommendation to meet your system’s performance and budget. 

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