For butterfly valve with metal seat, both sealing surfaces of valve are metal material or other hard material, which has not so good sealing performance, but has good mechanical properties, such as being high temperature resistant and anti-wear. While, for butterfly valve with resilient seat,one sealing surface is made of metal material and the other sealing surface is made of non-metal resilient material. Resilient seat has good sealing performance, but poor mechanical properties, such as not being high temperature resistant and easy to wear.
Resilient seated butterfly valve has good sealing performance and can reach zero leakage, but it has poor thermal adaptability and serves a short life. The hard seated butterfly valve has not good so sealing performance and can’t reach zero leakage, though some manufacturers declare that their products can do. Metal seated butterfly valve can be used in part corrosive medium, but Resilient seated butterfly valve can’t. The two different seats can complement each other in different working conditions.
Generally speaking, there are the following differences for butterfly valves of two different seats.
<1> Different Structure
Resilient seated butterfly valve is of central line design and Metal seated butterfly valve is of single , double or triple eccentric design.
<2> Different suitable temperature
Resilient seated butterfly valve is used in normal temperature,while Metal seated butterfly valve is used in low,normal and high temperature.
<3> Different pressure
Resilient seated butterfly valve is used in low and normal pressure and Metal seated butterfly valve can also be used in middle-high pressure.
<4> Different sealing performance
Resilient seated butterfly valve and Metal seated butterfly valve have comparative good sealing performance. The later can seal well in high pressure and temperature.