How does a suction feed spray gun function?

A suction feed spray gun functions by creating a vacuum at the nozzle, which draws paint from the cup into the airstream where it is atomized and sprayed onto the surface being painted. This vacuum is generated as air flows through the nozzle, where the pressure drops and causes the paint to be pulled up from the paint cup. This type of spray gun is popular for its ability to handle a variety of paint viscosities and allows for a consistent supply of paint as long as the cup remains filled.

The other methods presented in the choices do not accurately describe the operation of a suction feed spray gun. For instance, using a positive airflow to push paint is characteristic of pressure feed spray guns, not suction feed. Gravity feed mechanisms rely on the downward flow of paint and are utilized in different spray gun designs. Lastly, while atomization and fan pattern are important aspects of spray guns, a suction feed gun employs a vacuum mechanism specifically for drawing paint, making the focus on the fan pattern insufficient to explain its operation.