In the dust-laden cold air or hot air gas pipeline used in hard seal butterfly valve, chemical industry, building materials, power station, glass industry and other industries, this valve is generally installed horizontally as a gas medium to adjust the flow or cut off. The electric clip-on hard seal butterfly valve is used in the sulfur burning, conversion and dry absorption sections of the sulfur-based sulphuric acid plant, and is the first choice brand of valves for sulfur-based sulphuric acid plants.