Airless spray gun having tip discharge resistance

摘要

A spray gun (10) for airless atomization and electrostatic deposition of a coating material upon a substrate, including a gun nozzle tip element serving to prevent arcing from the gun nozzle to an adjacent electrical ground. As disclosed, the airless spray gun includes a metallic nozzle tip (26, 27) from which atomized liquid coating material is emitted, and the thus-emitted coating material is charged by an electrode (20) mounted on the nozzle which is electrically isolated from the metallic tip (26, 27). During use of the spray gun (10) the metallic tip (26, 27) becomes charged via electrical charge conduction through the emitted atomized coating material. To prevent arcing from the charged tip (26, 27) to an electrical ground, a pair of resistive threads (46, 47) are secured in bores in the spray gun nozzle, each having a first end electrically connected to the conductive tip (26, 27) and a second end extending slightly beyond the nozzle. If an electrical ground approaches the charge conductive tip (26, 27), the resistive threads (46, 47) are positioned such that electrical energy on the tip (26,27) is coupled to the electrical ground through one or both of the resistive threads (46, 47) in the form of a low energy corona discharge.