Normally for the technology process of the valve seat for soft seated type butterfly valves, it can be classified into two type: Vulcanization seat and the Normal seat.
The butterfly valve with the vulcanized seat refers to the rubber-lined butterfly valve, normally use of high temperature to vulcanize the rubber and the valve body at high temperature. The disadvantage of this kind of vulcanized seat is that the valve is disposable. If the vulcanized seat is damaged, the entire butterfly valve needs to be replaced.
Photos as below for information
2.Normal seat: exchangeable
The valve seat is separately installed in the body cavity of the valve body. This type of butterfly valve is mostly used in the pipelines with good sealing performance. Another advantage is that if only the rubber valve seat is damaged, only the valve seat can be replaced instead of the entire valve, which reduces the cost.
Photos as below for information.