TECHNICAL DATA SHEET

 

Spray applications, which are the most common paint application method, are based on the application of the paint by spraying it to be atomized in small droplets. Due to its diversity and ease of application, it has a wide range of uses.

 

Obtaining surfaces with uniform thickness distribution and well spreading has led to the diversification and widespread use of this method in industrial paint applications. However, the practitioner must use a mask and similar personal protective equipment. In addition, the amount of paint spreading to the environment during the application, in other words, the paint transfer efficiency varies according to each spray application.

 

Conventional (Air) Spray Applications

 

In the conventional spray application method, the liquid paint comes out of the narrow nozzle through the air spray gun, mixes with the compressed air and is sprayed in very small droplets. Paint can be supplied to the gun in one of three different ways. Different gun structures were designed for each method.

 

Pressure (Feed) Coated Gun: The paint in a container is delivered to the gun by passing through the hose with the pushing force created by applying 0.1–0.5 atm pressure. It is generally used for large quantities of dyeing. Better atomization is provided and less paint particles scattered around the environment. Top chamber gun: The paint is fed to the gun by the effect of gravity from a reservoir mounted on the gun. It is very suitable for small and frequent color changes.

 

Bottom chamber gun: The paint is fed to the gun with the effect of suction from a reservoir attached to the bottom of the gun. It is well suited for small-volume jobs with frequent color changes, such as overhead chamber guns.

 

In the pressure vessel, according to the upper chamber; In the upper chamber, smaller diameter nozzle can be used compared to the lower chamber. The paint fed to the air spray gun passes through the channels in the gun and reaches the paint nozzle (nozzle) at the end of the gun.

 

The air that the paint will mix with the paint during its exit from the gun nozzle reaches a pressure in the range of 2.5-5.5 atm with the help of a compressor. The mixing of paint and air can occur in two ways, depending on the air cap of the gun. Paint can be atomized both inside the gun (internal mix) and just outside the air cap (external mix).

 

Inner Mixture: The meeting of air and paint takes place just before the nozzle of the gun. It provides the use of less and lower pressure air in the internal mixture. It creates a wider beam, provides maximum film thickness and less overspray formation is observed.

 

Needle and nozzle must be disassembled and cleaned after each dyeing. Therefore, it is more suitable for the use of slow-drying materials. External Mixture: In such applications, the air is sprayed through the air ducts in the gun head and encounters the paint coming out of the nozzle of the gun and creates a mixture. It is a widely used method. A better atomization can be achieved with external mixing. The beam can be better controlled and can be used in bottom chamber guns because of its high pressure. It can be preferred in applications with fast drying and high quality surface expectations. It is easier to clean.