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The butterfly valve commonly divided in to these two general types, Concentric is sealed by the rubber, according to the rubber type it can be suitable for many substances, like water, or some chemical. But it usually used in below PN 16. Eccentric butterfly valve include the double or triple eccentric/offsets, the disc achieves a “cam-like rotation” during opening and closing, completely eliminating frictional wear. Taking the triple offset structure as an example, the valve stem axis forms a compound angle with the sealing surface, ensuring zero leakage even under high temperature and high pressure conditions.
So according to the working pressure and temp. The concentric Widely used in municipal water plants and building HVAC systems under low pressure (≤1.6 MPa) and ambient temperature conditions, they offer significant cost advantages and dominate over 80% of the basic market.
The double-offset design, utilizing rubber seals, is well-suited for handling corrosive media, making it a standard in the chemical industry. and The triple-offset metal-seated variant pushes performance to the extreme, temperatures up to 550°C, and is indispensable in applications such as power plant steam systems and LNG storage and transportation.
Industry experts recommend: For budget-constrained, standard conditions, concentric valves are the first choice. However, for applications involving particulate media, pressure surges, or those requiring 10 years of maintenance-free operation, although eccentric valves have an initial cost 30%–50% higher, their three times longer lifespan and near-zero failure rate can reduce lifecycle costs by 42% (calculated based on ISO 5208). Currently, the 316L stainless steel valve body combined with multi-layer metal sealing in three-eccentric butterfly valves is becoming the preferred solution in high-end sectors such as refining and nuclear power.
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