Abstract: A dual component pumping system comprised of a double-acting air motor alternately driving reciprocal pumps. Mechanically operated pilot valves activate a spool valve which reverses the air motor operation. Each pump has an inlet connected to a separate fluid component supply tank and an outlet connected to a spray gun through flexible hoses. A valve switching arrangement permits switching from one fluid to the other. The valve switching allows spraying of a fluid received from one pump while the other pump is in a bypass mode and recirculates fluid from its supply tank.

Abstract: A color change system for spray coating apparatus is characterized by two pumps, each of which is connectable with a selected color of coating material for providing the same to spray coating apparatus. The arrangement is such that the pumps alternately supply different colors of coating material to the coating apparatus, and when one of the pumps is supplying material the other is being cleansed of previously supplied material. In this manner, one pump is always clean and ready for supplying a newly selected color of material, so that any number of different colors of coating material may be provided to the coating apparatus with minimum numbers of pumps, e.g., two pumps. In one embodiment the color change system is used with automatic spray coating apparatus, and in another with manual or hand held coating apparatus.