There are many materials used for ventilation ducts, but the two most commonly used are as follows:
(1) sheet metal
Sheet metal is the main material for making air ducts and components. Commonly used are ordinary sheet steel, galvanized sheet steel, stainless steel sheet, aluminum sheet and plastic composite steel sheet. Their advantages are that they are easy to industrialize, easy to install, and can withstand higher temperatures. Anti-static air ducts should be made of metal materials.
◆Ordinary thin steel plate
It has good processing performance and structural strength, but its surface is easy to rust, so it should be painted for anti-corrosion treatment during production.
◆Galvanized sheet steel
It is made of galvanized ordinary thin steel plate. Due to the galvanized surface, it can play a role of rust prevention. It is generally used to make air ducts in humid environments without acid mist.
◆Aluminum and aluminum alloy plate
Good processing performance and corrosion resistance. It is not easy to generate sparks during friction and is often used in ventilation systems with explosion-proof requirements.
◆Stainless steel plate
With rust and acid resistance, it is often used in the production of moisture and acid-containing exhaust ducts and ventilation systems that require corrosion resistance in chemical environments.
◆Plastic composite steel plate.
Spray a layer of 0.2~0.4mm thick plastic layer on the surface of an ordinary thin steel plate. It is often used in air-conditioning systems with high dust-proof requirements and air ducts for corrosion-resistant systems at a temperature of 10~70°C.
The thickness of steel plate commonly used in ventilation engineering is 0.5~4mm.
(2) Non-metallic materials
◆Rigid PVC plastic board It is suitable for the ventilation system with an acid corrosion effect and has the advantages of a smooth surface and convenient production. However, it is not resistant to high temperature and cold and is only suitable for the air environment of 0~60°C. Under the action of solar radiation, it is easily brittle.
The inorganic FRP air duct is made of medium-alkali glass fiber as the reinforcing material, scientifically formulated with more than ten kinds of inorganic materials as the binder as the matrix, and is made by a certain molding process. It has the characteristics of lightweight, high strength, non-combustibility, corrosion resistance, high-temperature resistance and cold melting resistance. When selecting, you should know whether the oxygen index of FRP meets the fire protection requirements. The thermal insulation glass fiber reinforced plastic air duct can be made into an interlayer, and the thickness of the interlayer is determined according to the design. The sandwich material can be polystyrene, polyurethane foam, honeycomb paper and the like.
◆Phenolic aluminum foil composite air duct. It is made of phenolic aluminum foil composite sandwich panel, and the inner and outer surfaces are all aluminum foil. The phenolic aluminum foil composite air duct has good rigidity and air tightness, has thermal insulation performance, is lightweight and long service life. It has strong temperature adaptability and a wide application range.
◆Polyurethane aluminum foil composite air duct. It is made of polyurethane aluminum foil composite sandwich panel, and the inner and outer surfaces are all aluminum foil. Polyurethane aluminum foil composite air duct has good rigidity and air tightness, has thermal insulation performance, lightweight and long service life. Wide range of applications.
◆Glass fiber composite board air duct. The centrifugal glass fiber sheet is used, the outer wall is covered with aluminum foil, and the inner wall is covered with flame-retardant alkali-free or medium-alkali glass fiber cloth. It has the functions of heat preservation, noise reduction, fire prevention, moisture-proof and anti-corrosion. Lightweight and long service life.
◆Polyester fiber fabric duct. The cross-sectional shape is circular or semicircular. Longitudinal slits or circular orifices can be provided on the surface of the air duct to supply air. Lightweight, no noise, no condensation on the surface, easy installation and disassembly, easy cleaning and maintenance. Applicable to some production workshops and public building air-conditioning systems that allow air ducts to be installed.
◆Glass magnesium duct. According to the structure, the air duct is divided into the overall ordinary air duct, the overall thermal insulation type air duct, and the combined thermal insulation type air duct. The structural layer is composed of glass fiber cloth and magnesium oxychloride cement, and the thermal insulation material is polystyrene foamed plastic or lightweight thermal insulation sandwich panel. duct. The surface of the tube sheet is smooth and flat, and the air leakage rate is low. It has good sound insulation and sound absorption performance, non-combustibility, bending resistance, pressure resistance, low water absorption, no moisture absorption deformation, and long service life