This series of valves are widely used in ventilation and dust removal systems. They are used for flow regulation and closure of dusty gas, gas pipeline, ventilation and purification device, ventilation and purification device, flue gas pipeline, etc. This series of valves are welded with high-quality materials. It has the characteristics of stable and reliable operation, convenient operation, sensitive action, small leakage rate, long service life and convenient installation and maintenance. It is especially suitable for occasions with low pressure difference, large diameter and large flow. It is combined with various actuators to form valves with different performance.