Metal high-pressure airless spraying
High-pressure airless metal spraying is a coating technology that uses a high-pressure pump to pressurize the paint to 15-30 MPa, atomizes the paint through a special nozzle, and sprays it onto the metal surface to form a coating. Unlike traditional air spraying, this technology does not require compressed air to assist in atomization. Instead, it relies on high pressure to release the pressure of the paint at the nozzle, forming a high-speed spray stream, thereby achieving uniform coating. This spraying method effectively reduces paint atomization losses and improves paint utilization. It also avoids coating defects caused by moisture and oil contamination in compressed air during air spraying. It is particularly suitable for coating large metal structures such as bridges, storage tanks, and ships.
The core equipment for high-pressure airless metal spraying includes high-pressure plunger pumps, spray guns, paint containers, feed hoses and nozzles. The high-pressure plunger pump is a key component that provides power. It drives the plunger to reciprocate through a motor to pressurize the paint to the set pressure. The pressure adjustment range is usually 5-30MPa, which can be flexibly adjusted according to the viscosity of the paint and the spraying requirements. The spray gun is equipped with a pressure control switch and a nozzle. The aperture and shape of the nozzle determine the atomization effect and spraying range of the paint. The commonly used nozzle aperture is 0.2-2.0 mm, and the fan-shaped nozzle has a spraying range of up to 10-60 cm, which can meet the spraying needs of workpieces of different sizes. The feed hose is made of high-strength and wear-resistant materials that can withstand the transportation of high-pressure paint. The length is usually 5-50 meters, which is convenient for operators to move around in a larger range.
The process advantages of metal high-pressure airless spraying are very significant. First of all, the paint utilization rate is high, reaching 80%-90%, which is much higher than the 30%-50% of air spray. This is because the paint atomization particles of high-pressure airless spray are larger and the splash loss is less. It is especially suitable for thick film coating and can reduce paint waste and environmental pollution. Secondly, the spraying efficiency is high. The spraying speed of a single gun can reach 10-30 square meters per hour, which is 2-5 times that of air spraying. For the coating of large metal components (such as 10,000-ton storage tanks), the construction period can be greatly shortened. In addition, this technology can achieve a thicker dry film thickness. The dry film thickness of a single spray can reach 30-150 microns, which reduces the number of coating passes and is particularly suitable for the construction of heavy anti-corrosion coatings.
