Flange ball valve apply to: Oil/nature gas/coal mine/ore mining, refining and pipeline transport systems; Chemical products, medicinal & pharmaceutical products and food producing; Hydropower/thermoelectricity and nuclear power production system; Drainage/heating/airing system in cities and industrial enterprises; Irrigation and drainage network; metallurgical production system; They are essential mechanical products that closely interrelated with production & construction, national defense construction and people’