| 摘要 |
A plural component airless spray gun for reactive liquid materials has a mix chamber (68) into which coreactive liquid component are introduced and mixed, an airless tip at a forward outlet from the chamber from which the mixed components are emitted in a fan-shaped spray, and a mechanically operated purge rod (78) for cleaning residual reactants from the mix chamber (68) and airless tip (70). The purge rod (78) has a main body of a diameter slightly less than that of the mix chamber (68) and a probe at its forward end that geometrically conforms to and is adapted to enter into and clean the inside of the spray tip. During spraying the purge rod (78) is retracted in the mix chamber (68) rearwardly of liquid reactant inlets to the chamber. Upon completion of spraying or periodically as desired, the purge rod (78) is moved forwardly to clean the mix chamber (68) and the inside of the airless tip of residual reactive components. To prevent damage to the airless tip should the probe of the purge rod encounter cured material within the tip or the tip itself as the purge rod is moved forward, the purge rod (78) is moved forward by a piston assembly that is structured to decrease the forward driving force exerted on the purge rod when its probe is in the airless tip. |
