Spray system pump wash sequence
AssigneeGraco Minnesota Inc.
InventorsDavid L. Fehr, Dennis J. Van Keulen
Life of this patent
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Abstract
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 a compressed air source, and an outlet of the common pump to a waste fluid dump, filling the common pump with a first purge volume of solvent, cycling the common pump in a flush mode, operating the common pump in a timed flow mode, and 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 of a second fluid from the second primary fluid source through the output line.
Claims15
A fluid change method for a multi-fluid spray system having a plurality of primary fluid sources with an output line and a common pump, the method comprising:
- halting pumping of a first fluid from a first primary fluid source through the output line;
- isolating the common pump from the output line and the primary fluid sources;
- connecting an inlet of the common pump to a solvent source and a compressed air source, and an outlet of the common pump to a waste fluid dump;
- filling the common pump with a first purge volume of washing solvent from the solvent source;
- cycling the common pump in a flush mode to flush dirty solvent from the common pump;
- operating the common pump in a timed flow mode to fill the common pump with an air stream from the compressed air source and washing solvent in an alternating fashion;
- connecting an inlet of the common pump to a second primary fluid source, and actuating the pump in the pumping mode;
- connecting an outlet of the common pump to the output line;
- and
- starting pumping of a second fluid from the second primary fluid source through the output line.
A spray system comprising:
- a first fluid source and a first sprayer for a spraying first spray fluid;
- a second fluid source and a second sprayer for spraying a second spray fluid;
- a solvent source for providing a washing solvent;
- a compressed air source for providing an air stream;
- a waste fluid dump;
- a pump comprising:
- a metered double-action pumping cylinder with a reciprocating plunger;
- first and second inlet valves;
- and
- first and second outlet valves;
- a valved inlet manifold configured to selectively couple the pump to the first and second fluid sources, the solvent source, and the compressed air source;
- a valved outlet manifold configured to selectively couple the pump to the first and second sprayers and the waste fluid dump;
- and
- a controller configured to control the pump to spray the first fluid during a first operational state and the second fluid in a second operational state;
- and to transition from the first operational state to the second operational state via an intermediate washing process wherein during the intermediate washing process the valved inlet manifold connects the pump to the solvent source and the compressed air source, the valved outlet manifold connects the pump to the waste fluid dump, and the pump is actuated first in a pumping mode to flush the first fluid from the pump, then in a timed flow mode mode to direct washing solvent and compressed air through the pump, and then a flush mode to flush waste air and solvent from the pump.
Dependencies are inferred from the claim text.