The amount of paint required to complete the painting job determines the type of spray equipment used. Generally, according to the amount of paint, it can be divided into three situations: small-scale coating, medium-scale coating and large-scale coating.
1. Small-scale painting
Generally, the spraying amount of paint per day is within the range of 1ga1 (3.9L), which is called small-scale painting, such as spraying a car, a single piece of furniture, or performing daily repair painting. At this time, the spraying equipment generally uses an air atomizing Spray Gun, and it is a small Spray Gun for light repairs, usually a suction or gravity Spray Gun. These two types of Spray Guns are light and handy, easy to operate by hand, and are suitable for spraying objects with less paint consumption and frequent color changes. There are two types of atomization methods: outdoor hybrid atomization and internal hybrid atomization.
The internal mixing type has low air consumption, produces less scattered paint mist, and has a larger spray pattern diameter, but the paint has a greater wear on the nozzle, so it is rarely used at present, and the external mixing type nozzle is mostly used to meet production requirements. You can also use a pressure-feed Spray Gun to supply paint with a small pressure tank with a volume of 7-8L. A small electric portable Air Compressor with a power of 0.25~1.0hp (183.75~735W) can be used as the compressed air source to provide pressure for the paint tank and air Spray Gun. To ensure the cleanness of the compressed air, air filtering equipment and pressure adjustment should be equipped equipment. To connect the paint hose between the pressure tank and the Spray Gun, use a thin tube with an inner diameter of 1/4~3/8in (5~7.5mm). In order to prevent paint spray from harming workers' bodies, self-priming filter respirators should be cut off during operation.
2. Medium-scale painting
Generally, the amount of paint sprayed per day is 5ga1 (about 20L), which is called medium-scale painting, such as the painting of buildings such as warehouse workshops, and the painting of batches of products in small painting workshops or large-scale painting of automobiles. The workpiece is divided into pieces for single coating, which belongs to medium-scale coating. This kind of painting should generally be carried out in the spraying room of the painting workshop. The spraying equipment used can be various air atomizing Spray Guns, but the pressure-fed air Spray Gun with a large amount of paint delivery is more suitable. Paint booster tanks can be used to transport paint, and electric or pneumatic fixed or movable Air Compressors with a power of 1.5~10hp (1.1~7.35kW) can be used to supply compressed air. In order to purify the compressed air, equipment such as gas cylinders, air pressure regulators, oil-water separators and air filters should be equipped. When the spraying workload is large and the spraying atomization effect is not very high, you can also use a high-pressure airless atomizing Spray Gun. In order to better reduce the viscosity of the paint and reduce the amount of solvent used, you can consider using a heating device. High pressure airless spraying equipment. In order to improve the atomization effect of the paint, air-assisted high-pressure spraying equipment can also be used. In order to prevent the paint from settling, it is better to equip the agitator and filter in the delivery pipeline. In order to reduce the pressure drop caused by conveying paint, a paint hose with a larger diameter should be selected, generally with an inner diameter of 5/16~1/2in (8~12.7mm). In order to facilitate the disassembly and assembly of pipelines, joints that can be quickly assembled and disassembled are generally selected. When using high-pressure airless spraying, in order to ensure safety, it is necessary to choose a high-pressure resistant paint hose and a joint with a threaded interface. The Spray Guns used can be selected from standard production Spray Guns, repair Spray Guns or other special Spray Guns according to actual needs. Due to the increased spraying workload, in order to prevent paint mist from harming workers, operators should wear protective masks or gas masks.
3. Large-scale painting
When the amount of paint consumed by spraying operations exceeds 55ga1 (about 215L) per day, it is called large-scale painting, such as painting automobiles, electrical appliances and other products in batches or painting large-scale equipment in large-scale painting vehicles. pretend to wait. For small batch or repair painting, manual spraying can be used. When coating a large number of workpieces with the same shape, in order to improve productivity and reduce labor intensity, automatic assembly lines should be used for spraying.
Large-scale coating can use external mixing air atomization Spray Gun, high-pressure airless Spray Gun, and electrostatic atmosphere Spray Gun can also be considered, because it has less flying paint, high paint rate, high construction efficiency, continuous automatic production, and equipment Advantages of small footprint. At present, electrostatic spraying equipment has been used in the automatic production lines of automobiles, refrigerators, household appliances, etc. The compressed air source matched with the spraying equipment also needs stronger working capacity, and the power of the fixed or mobile electric and pneumatic Air Compressors used should be above 10hp (7·35kW). To purify the compressed air, equipment such as air dryer, aftercooler, pressure regulator and filter should be equipped. In order to transport paint, it is necessary to equip related equipment such as pressure vessel or booster pump. The Spray Guns used should consider the use of heavy-duty production Spray Guns with higher structural strength, heated airless Spray Guns, and electrostatic spray special Spray Guns.
