Spray system pump wash sequence

Patent metadata

Field	Value
Publication number	US-9901945-B2
Application number	US-201414904655-A
Country	US
Kind code	B2
Filing date	Jul 18, 2014
Priority date	Jul 19, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

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 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.

First claim

The invention claimed is:

1. 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 that is a double-action linear pump with a reciprocating plunger and up and down inlet and outlet valves, 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 an outlet of the common pump to a waste fluid dump;
actuating the common pump in a pumping mode to flush the first fluid from the common pump, and fill the common pump with washing solvent from the solvent source;
actuating the common pump in a recirculation mode by alternatingly executing down- and up-strokes of the reciprocating plunger with all of the inlet and outlet valves open to turbulently circulate the washing solvent within the common pump;
actuating the common pump in a flush mode to flush dirty solvent from the common pump;
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.

2. The method of claim 1 , wherein actuating the common pump in a pumping mode comprises alternatingly executing a down-stroke of the reciprocating plunger with the down inlet and outlet valves open and the up inlet and outlet valves closed, and an up-stroke of the reciprocating plunger with the up inlet and outlet valves open and the down inlet and outlet valves closed.

3. The method of claim 1 , wherein isolating the common pump from the output line and the primary fluid sources comprises closing valves connecting the output line and the solvent source.

4. The method of claim 3 , wherein a valved inlet manifold selectively couples the inlet of the common pump to the first and the second fluid sources and the solvent source, individually.

5. The method of claim 1 , wherein connecting an outlet of the common pump to a waste fluid dump comprises closing valves connecting the common pump to the output line and opening valves connecting the common pump the waste fluid dump.

6. The method of claim 5 , wherein a valved outlet manifold selectively couples the outlet of the common pump to the outlet line and the waste fluid dump, individually.

7. The method of claim 1 , wherein the washing solvent is an alcohol, ester, ketone, aliphatic petroleum naphtha, or aromatic hydrocarbon.

8. A spray system comprising:
a first fluid source and a first sprayer for spraying a 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 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 and the solvent 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, 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 recirculation mode that alternatingly executes down- and up-strokes of the reciprocating plunger with the first and second inlet valves and the first and second outlet valves open to turbulently circulate the washing solvent within the pump, and then a purge mode to flush waste solvent from the pump.

9. The spray system of claim 8 , wherein the first operational state comprises:
the valved inlet manifold connecting the pump to the first fluid source;
the valved outlet manifold connecting the pump to the first sprayer; and
the pump actuating in the pumping mode to pump the first fluid through the sprayer.

10. The spray system of claim 8 , wherein actuating the common pump in a pumping mode comprises:
alternatingly executing a down-stroke of the reciprocating plunger with the first inlet and outlet valves open and the second inlet and outlet valves closed and an up-stroke of the reciprocating plunger with the second inlet and outlet valves open and the first inlet and outlet valves closed.

11. The spray system of claim 8 , wherein the solvent is an alcohol, ester, ketone, aliphatic petroleum naphtha, or aromatic hydrocarbon.

12. The spray system of claim 8 , wherein valving of the pump, the valved inlet manifold, and the valved outlet manifold are all controlled by the controller.

Assignees

• Graco Minnesota Inc

Inventors

• Fehr David L
• Van Keulen Dennis J

Classifications

• F04B39/0292

  Lubrication of pistons or cylinders · CPC title

• F04B49/22

  by means of valves (F04B49/03 takes precedence) · CPC title

• B05B7/2497

  several liquids from different sources being supplied to the discharge device · CPC title

• F04B39/10

  Adaptations or arrangements of distribution members · CPC title

• F04B13/00

  Pumps specially modified to deliver fixed or variable measured quantities · CPC title