Sealing Principle of Double Offset Butterfly Valve

Sealing Principle of Double Offset Butterfly Valve

Double offset butterfly valve sealing structure, which generally can use PTFE, synthetic rubber to form a composite seat. Its characteristic is that the elasticity of the valve seat is still provided by synthetic rubber and the service life of butterfly valve is improved by using PTFE as sealing surface material because of its low friction coefficient, non-wear and non-ageing characteristics.

On the basis of double offset butterfly valve, the manufacturer of Zhengfeng Valve forms a beta angle offset between the center line of the seat and the center line of the valve body, which makes the sealing surface of the butterfly plate immediately detached from the sealing surface of the valve seat at the opening moment, and contacts and tightens the sealing surface of the valve seat at the closing moment. When fully opened, the clearance between the two sealing surfaces is the same as that of the double eccentric sealing butterfly valve. The design of this kind of butterfly valve completely eliminates the mechanical wear and abrasion between the two sealing surfaces, and greatly improves the sealing performance and service life of the butterfly valve. Because the rotation center of butterfly plate (i.e. the center of valve shaft) and the sealing section of butterfly plate are set eccentrically, the sealing surface of butterfly plate gradually separates from the sealing surface of the valve seat during the opening process. When the butterfly plate rotates to 20~25 degrees, the sealing surface of the butterfly plate completely separates from the sealing surface of the valve seat. When the butterfly plates are fully opened, the gap between the two sealing surfaces forms, which makes the butterfly valve two seals in the opening and closing process. The relative mechanical wear and extrusion between surfaces are greatly reduced, thus ensuring the sealing of butterfly valves.

Zhengfeng is one of the leading manufacturers of double offset butterfly valves in China. Welcome to inquire!

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