Different valves affect the fluid flow, air flow, and spray pattern of a dispensing unit. Installed at the inlet of the gun, the air valve affects pressure coming into the gun. Also known as pressure regulators, these valves may contain gauges for precise control over pressure levels. Replaceable air adjustment valves are available with and without gauges. Digital, battery-powered gauges feature an LCD display for accurate psi levels.
Fluid control knobs affect the inline valve. Normally located near the liquid tubing nozzle, fluid control knobs affect the position of the trigger. Tightening the springs allows the trigger to potentially open the valve completely. When the trigger is pulled, maximum fluid flow results in ideal atomization and spray control.
Pattern control knobs determine the orientation of the spray pattern. An internal valve may have two or more stops that lock into designated positions. Most spray guns achieve horizontal and vertical spray patterns through the pattern control knob. The valve position controls the flow of fluid to spray accordingly.