It is reported that the square butterfly valve was finally produced under the auspices of the Ministry of Technology and with the concerted efforts of all comrades of the company. It has the characteristics of light weight, small leakage, small flow resistance, simple structure and flexible start-up. It can be used as ventilation and adjustment equipment in ventilation and dust collection pipeline. It is mainly suitable for ventilation and dust removal and environmental protection in metallurgy, mining, cement, chemical industry, power generation and other industries.