Concentric Double Flange Butterfly Valve AEA Resilient Seated Butterfly Valves are widely used in various industries for both on-off and regulating service. Compare with traditional Globe & Ball valve, butterfly valve is less weight and cost-effective. Followed by the rapid development on various elastomer materials, resilient seated butterfly valve are now used not only for water system but also for various chemical industries. AEA resilient seated butterfly valves are designed in accordance with API609 with axes of body,stem and disc concentric.