US Patent 9901945 Spray system pump wash sequence

A method for a system having a plurality of primary fluid sources and a fluid output with a common pump includes halting pumping of a first fluid, isolating the common pump from the fluid output and the primary fluid sources, connecting an inlet of the common pump to a solvent source and an outlet of the common pump to a waste fluid dump, actuating the common pump first in a pumping mode, then in a recirculation mode, and then in a flush mode, connecting an inlet of the common pump to a second primary fluid source, and an outlet of the common pump to the output line, and starting pumping mode pumping of a second fluid from the second primary fluid source through the output line.