Spiral duct is called so because the shape of the pipe is spiral. The reason why the pipe of HVAC adopts spiral pipe is that the spiral shape of the pipe wall can block the flow rate of the fluid in the pipe and better carry out the energy transfer. For example, in winter, the spiral pipe is filled with hot water, which can better heat transfer.
Spiral wind pipe is the first to be used in some foreign and joint ventures. Because the spiral duct has a spiral seam, the strength can be increased by 30%, so the thinner material can be used. For example, the thickness of 0.8mm can be changed to 0.6mm. In addition, under the same cross-sectional area, the use of spiral duct can save 20% of the material.
Iron is easy to react with chemicals in various environments, resulting in corrosion and rust of air ducts, while zinc hardly changes in dry air. In humid air, dense basic zinc carbonate film will be formed on the surface of zinc. The spiral air duct is mainly coated with a layer of zinc on the iron of the air duct to protect the iron. After passivation, dyeing or coating, the protective and decorative properties of zinc coating can be significantly improved.