There are several types of air duct:
Flanged flange wall pipe, Common plate flange pipe, Angle steel flange pipe, Spiral duct, Welded pipe, Shaped pipe fittings
Flanged flange wall pipe
High air volume, high wind pressure, high sealing requirements of supply air, return air, exhaust air, fresh air and other craft ventilation system
Common plate flange pipe
Comfort ventilation system for supply air, return air, exhaust air and fresh air
Angle steel flange pipe
Comfort ventilation system for supply air, return air, exhaust air and fresh air
Spiral duct
Comfort ventilation system for supply air, return air, exhaust air and fresh air
Welded pipe
Comfort ventilation system for supply air, return air, exhaust air and fresh air
Shaped pipe fittings