Abstract: An air-operated spray gun for spraying two fluid components in proportional amounts has the fluids fed separately from a pair of fluid cylinders each containing a fluid-operated double-acting piston with the volumes of each cylinder being in accord with the desired proportion of the fluids. The fluids are fed from the cylinders through fluid flow control valves which are switchable between a first position for directing fluid from a fluid source into one end of its associated cylinder and out the opposite end of the cylinder to the spray gun and a second position for directing the fluid out of the one end of the cylinder to the spray gun and into the opposite end of the cylinder from the fluid source. Air control valves instantaneously switch the fluid flow control valves from one position to the other. Sensing devices operate the air control valves when the cylinder pistons reach the ends of their strokes.

Abstract: An air-operated fluid spray gun for mixing multiple fluids together almost simultaneously with depositing the mixture on a surface by directing an atomized stream of one fluid out the end of the gun barrel toward the surface and injecting an atomized stream of another fluid generally radially into the first stream so that the streams mix thoroughly and the mixture is almost simultaneously deposited on the surface.

Abstract: To seal against liquid leaking out around a rod which is slidably movable lengthwise axially within a chamber containing the liquid through an opening in the rear wall of the chamber, a ring of thermoplastic material is placed in the chamber around the rod and pressed against the rear wall of the chamber while applying heat to cause the thermoplastic material to flow into the opening around the rod and onto the outside of the wall so that when the heat is removed the material sets and latches itself onto the rear wall to seal off the space around the rod while still allowing the rod to slide easily.