Second, the advantage of pneumatic plug valve is that the valve can be opened and closed by rotating the cutting rod through pressure. The operation of air pressure as power can save a lot of resources, which can save a lot of costs for enterprises. The traditional plug valve has small fluid resistance, but poor sealing. The improved pneumatic plug valve has a strong sealing performance, because the improved pneumatic plug valve is completely operated by air pressure, which improves the sealing performance on the basis of keeping the original advantages of low flow resistance. 　　

2. Non metallic materials General non-metallic materials cannot accept high temperatures (above 300 ° C), but flexible graphite can accept high temperatures above 700 ° C. Therefore, under high temperature conditions, whether static or dynamic seals, flexible graphite or composite materials can generally be selected, but it should be noted that the friction coefficient will increase.