Common materials and shapes for ventilation ducts
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In  order to better grasp and use the ventilation pipe, we will come to a  detailed understanding of the ventilation pipe commonly used materials  and shapes. I hope to help you choose to buy.

First, commonly used materials
There are many materials for the ventilation ducts used as spiral  ducts. Commonly used are metal sheet and non-metallic materials.
1, metal sheet
Commonly  used metal sheet has ordinary steel plate, galvanized steel sheet,  stainless steel plate, aluminum plate and plastic composite board. With easy to industrial production, easy installation, can withstand the advantages of higher temperature.
2, non-metallic materials
Commonly used hard polyvinyl chloride plastic sheet and FRP, the  characteristics of various materials duct, specifications and scope of  application see the "ventilation design manual."
Second, the duct shape and specifications
1, wind pipe section shape
Ventilation pipe cross-section shape is round and rectangular two. In  the same cross-sectional area under the conditions of the spiral duct  is short and the most economical, in the same air volume under the air  duct than the spiral duct pressure loss is so large under the  circumstances are used circular duct, and sometimes only for the  convenience and construction Only use the moment section. By  the rectangular duct pressure loss formula can be drawn: the pressure  loss of the rectangular duct increases with the duct width ratio  increases correspondingly. Therefore, when setting the juice, make the aspect ratio close to l. Of course, sometimes depends on the scene.
2, ventilation pipe specifications
Ventilation, air conditioning system duct, should adopt the spiral duct. Length and length of not more than 4 rectangular cross-section, the  maximum length of the short side of the ratio should not exceed 1O, the  size of the duct, should be the current national standard ventilation  and air conditioning construction quality acceptance of the provisions  of the provisions of the implementation.
3, duct insulation
When  the duct in the delivery of air process towel hot and cold loss of  large and requires the air temperature to maintain a constant, or to  prevent the duct through the room when the indoor air parameters affect  or discharge of the gas before the atmosphere may be draped to form a  condensate Clogging or corroding the duct and the surface of the spiral duct may have condensation, the need for duct insulation. Usually the insulation layer has a layer of insulation layer, moisture-proof layer and protective layer.