This series is designed for lightweight ventilation valve dust ventilation duct design. Structure of short, light weight, easy maintenance. This series of butterfly shape with its diverse shapes and structures can be adapted to a variety of pipes and different requirements. The valve is widely used in industrial and mining enterprises, urban construction and civil defense facilities smoke, dust, ventilation and heating series do regulate and control air flow purposes. This series of lightweight ventilation butterfly valve round, rectangular single blade, multi-blade rectangular form. Users may also be required to design and manufacture of other forms of light ventilation valve.