What are the main considerations for spraying air duct vibrating screen

Source：www.dqig.cn Release date： 2024年12月03日

Information summary：When spraying the air duct vibrating screen, the following aspects should be noted: 1. Surface pretreatment Clean the surface Firstly, it is necessary to remove impurities such as dirt, grease, dust, and rust from the surface of the air duct vibrating screen. Special cleaning agents and tools such as organic solvents can be used to clean oil stains, and steel wire brushes or sandpaper ca

When spraying the air duct vibrating screen, the following aspects should be noted:
1. Surface pretreatment
Clean the surface
Firstly, it is necessary to remove impurities such as dirt, grease, dust, and rust from the surface of the air duct vibrating screen. Special cleaning agents and tools such as organic solvents can be used to clean oil stains, and steel wire brushes or sandpaper can be used to remove rust. For example, for areas with heavy oil stains, acetone or industrial alcohol can be used to wipe the surface clean, as these impurities can affect the adhesion of the coating.
After cleaning, the surface should be dried and wiped clean with clean compressed air or a dry cloth to avoid residual moisture and prevent coating bubbles or peeling after spraying.
Surface roughness treatment
Properly increasing surface roughness can improve the adhesion of coatings. Surface treatment methods such as sandblasting and shot blasting can be used, but attention should be paid to controlling the strength and depth of the treatment. For example, during sandblasting treatment, the size of sand particles, the pressure and time of sandblasting should be determined according to the material and coating requirements of the air duct vibrating screen to avoid surface damage or deformation caused by excessive treatment.
2. Coating selection
Select based on operating conditions
Consider the working environment of the vibrating screen, such as temperature, humidity, and whether it comes into contact with corrosive media. If the working environment has high humidity or comes into contact with corrosive materials, coatings with good moisture-proof and anti-corrosion properties should be selected. For example, the air duct vibrating screen used in the food processing industry may require the selection of non-toxic coatings that meet food safety standards; In the chemical industry, it may be necessary to choose coatings that are resistant to chemical corrosion such as acid and alkali.
For parts with wear resistance requirements, such as the vibrating screen mesh and areas with frequent material contact, coatings with good wear resistance should be selected. For example, coatings containing wear-resistant materials such as ceramic particles can be chosen to extend the service life of the equipment.
Coating compatibility
Ensure that the selected coating is compatible with the material of the air duct vibrating screen. Different metal materials (such as carbon steel and stainless steel) have different adsorption and chemical reactivity towards coatings. For example, for stainless steel vibrating screens, certain coatings containing heavy metal components may cause corrosion on the stainless steel surface, so it is necessary to choose suitable stainless steel specific coatings or coatings that have been verified to be compatible with stainless steel.
3. Spraying process
Spray environment control
The temperature and humidity of the spraying environment have a significant impact on the quality of the coating. Generally speaking, the temperature should be controlled within the recommended range in the coating product manual, usually between 5-35 ℃. The humidity should not be too high, and the ideal relative humidity should be below 80%, as excessive humidity may cause the coating to dry slowly, resulting in phenomena such as sagging and whitening.
The spraying site should be kept clean and well ventilated to avoid dust and impurities from entering the coating. At the same time, ventilation helps to evaporate solvents in the coating and reduce safety hazards.
Spray equipment and parameter adjustment
Select appropriate spraying equipment, such as spray guns, paint cans, etc., based on the type and requirements of the coating. For large-area duct vibrating screens, spray guns are generally used. Adjust the nozzle size, spraying pressure, and spraying distance of the spray gun. For example, the spraying distance of the spray gun is generally kept between 15-30cm, which can evenly distribute the coating on the surface and avoid uneven spraying or coating accumulation.
Use the correct spraying technique, such as moving the spray gun evenly, to avoid staying in one place for too long and causing the coating to become too thick. Generally, the cross cross method can be used for spraying, which means spraying a layer in one direction first, and then spraying a layer vertically to ensure the integrity and uniformity of the coating.
4. Coating quality control
Coating thickness detection
During the spraying process, attention should be paid to controlling the thickness of the coating. Magnetic thickness gauges or eddy current thickness gauges can be used for testing. The coating thickness should comply with the requirements of the coating product manual. Generally, the thickness of the primer may be between 20-50 μ m, and the thickness of the topcoat may be between 30-80 μ m. If the coating is too thin, it may not achieve the expected protective and decorative effects; If it is too thick, quality problems such as cracking and peeling are prone to occur.
Coating drying and curing
According to the instructions for using the coating, ensure that the coating has sufficient time for drying and curing. Some coatings require natural drying at room temperature, while others may require baking and curing at a certain temperature. For example, some thermosetting coatings require baking at 80-120 ℃ for 1-2 hours to achieve good performance. Do not use a vibrating screen until the coating is completely dry and cured to avoid damaging the coating.

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