The sealing forms of stainless steel lug butterfly valves are mainly as follows
Elastic seal (soft seal) :
This sealing form uses elastic materials (such as rubber, polytetrafluoroethylene PTFE, etc.) as sealing elements, and fills the small gap between the sealing surface through elastic deformation, so as to achieve sealing. The elastic seal butterfly valve usually has good sealing performance and low opening and closing torque, and is suitable for occasions where the temperature is not high and the medium is not strong corrosive.
Metal seal (hard seal) :
The metal sealing butterfly valve uses metal materials (such as stainless steel, alloy steel, etc.) as the sealing surface, which is sealed by contact and extrusion between metals. The metal sealed butterfly valve has high temperature resistance, high pressure resistance and corrosion resistance, and is suitable for harsh working conditions such as high temperature, high pressure and strong corrosive media. However, the opening and closing torque of the metal sealed butterfly valve is usually large, and the sealing performance is greatly affected by medium pressure fluctuations and temperature changes.
Composite seal:
The composite seal butterfly valve combines the advantages of elastic seal and metal seal, and adopts the design of metal sealing surface and elastic sealing element. This sealing form can not only ensure the sealing performance under high temperature, high pressure and strong corrosive media, but also reduce the opening and closing torque and improve the operation convenience of the valve. The composite seal butterfly valve is usually suitable for occasions with high sealing performance requirements.
Multi-layer seal:
The multi-layer sealing butterfly valve adopts a multi-layer sealing structure to improve the sealing performance by increasing the number of sealing layers and the contact area of the sealing surface. This sealing form is suitable for applications with very high sealing requirements, such as the control of ultra-high temperature, ultra-high pressure or highly corrosive media.