Paint spraying equipment and method of cleaning the same

• US 6,037,010 A
• Filed: 06/26/1998
• Issued: 03/14/2000
• Est. Priority Date: 07/03/1997
• Status: Expired due to Term

• Current Assignee: Lactec Gesellschaft Fuer Moderne Lackiertechnik Mbh
• Original Assignee: Lactec Gesellschaft Fuer Moderne Lackiertechnik Mbh
• Inventors: Kahmann, Ralf, Klein, Udo, Weiss, Volker, Ott, Winfried
• Primary Examiner(s): Beck, Shrive
• Assistant Examiner(s): CALCAGNI, JENNIFER A
• Application Number:
  US09/105,505
• Time in Patent Office: 627 Days
• Field of Search: 118/302, 427/421, 222/148, 222/334, 239/112, 239/113, 239/116
• US Class Current: 427/426
• CPC Class Codes: B05B 12/1481 comprising pigs, i.e. movable elements sealingly received in supply pipes, for separating different fluids, e.g. liquid coating materials from solvent or air cleaning pipes with pigs B08B9/0557, pigs per se F16L55/26

Abstract

In a method of cleaning a paint application system when switching between two different types or colors of paint, at least a predominant portion of the first paint (35) remaining in a paint line (3) is caused to flow back into its paint supply container (5). Then the entire paint line is flushed out using a flushing medium, before supplying the second paint through the paint line. In this manner, the paint remaining in the painting system at the end of a painting cycle is not wasted, but rather is saved to later be reused. A paint application apparatus includes a paint supply switching device (4), at least two paint supply containers (5 to 8), a paint spray nozzle (2), and a paint line (3) connecting the color switching device (4) to the spray nozzle (2). Two receiver stations (28) and (31) are interposed in the paint line (3), and a shuttle element in the form of a pipe cleaner swab (29) is arranged in the paint line (3) so as to be able to shuttle back and forth between the two receiver stations. A pressure medium or flushing medium can be introduced into the paint line (3) between the first receiver station (28) and the spraying nozzle (2), so as to push the pipe cleaner swab (29) through the paint line (3) to the second receiver station (31). Thereby, the paint remaining in the paint line (3) is pushed back into the paint supply container.

Claims

1. A paint application system comprising:

a paint supply switching device including at least one paint supply line;

a paint applicator;

a paint line connecting said paint supply switching device to said paint applicator;

first and second receiver stations interposed in said paint line between said paint supply switching device and said paint applicator, with said first receiver station adjacent said paint applicator and said second receiver station adjacent said paint supply switching device;

a shuttle element that is arranged in and movable back and forth through said paint line between said first and second receiver stations, wherein said shuttle element and said first receiver station are so configured that paint can flow past said shuttle element through said first receiver station when said shuttle element is located in said first receiver station during a paint application stage; and

a connector arrangement connected to said paint line at a location selected from said first receiver station, said paint applicator, and between said first receiver station and said paint applicator, wherein said connector arrangement is adapted to supply an auxiliary medium into said paint line at said location so as to push said shuttle element from said first receiver station through said paint line into said second receiver station during a paint recovery stage.

2. The paint application system according to claim 1, wherein said paint supply switching device further comprises a respective controllable valve arranged in each said at least one paint supply line, and a controller unit connected to each said respective controllable valve.

3. The paint application system according to claim 2, wherein said at least one paint supply line includes at least first and second paint supply lines, and further comprising at least first and second paint supply containers that are respectively connected with said first and second paint supply lines and that are respectively adapted for containing first and second different paints therein.

4. The paint application system according to claim 2, wherein said paint supply switching device further comprises a flushing medium supply line adapted to be connected to a source of a flushing medium, a pressurized air supply line adapted to be connected to a source of pressurized air, a drain line, and a common supply line connected in flow sequence order to said pressurized air supply line, said flushing medium supply line, said drain line, said at least one paint supply line, and then to said paint line.

5. The paint application system according to claim 1, wherein said paint applicator comprises a spraying nozzle.

6. The paint application system according to claim 1, wherein at least one of said receiver stations comprises a removal station associated therewith and adapted to allow said shuttle element to be removed through said removal station.

7. The paint application system according to claim 1, further comprising a sensor arranged in or at said second receiver station and adapted to sense the presence of said shuttle element.

8. The paint application system according to claim 1, further comprising a paint dosing device connected to said paint supply switching device.

9. The paint application system according to claim 1,

wherein each one of said receiver stations respectively comprises a housing wall with a chamber therein, and a passage opening and a fluid flow opening extending through said housing wall and into said chamber at opposite ends thereof,

wherein said chamber has a lateral dimension greater than a diameter of said shuttle element so that said shuttle element can be received in said chamber with a flow space between said shuttle element and said housing wall allowing fluid flow from said passage opening past said shuttle element to said fluid flow opening,

wherein said passage opening of each said receiver station has a diameter equal to or greater than said diameter of said shuttle element and is respectively connected to a portion of said paint line extending between said first and second receiver stations, and

wherein said fluid flow opening of said first receiver station is connected to a portion of said paint line extending between said first receiver station and said paint applicator, and said fluid flow opening of said second receiver station is connected to a portion of said paint line extending between said second receiver station and said paint supply switching device.

10. The paint application system according to claim 9, wherein each said receiver station further comprises a stop member connected to said housing wall and protruding into said chamber adjacent said fluid flow opening so as to stop travel of said shuttle element toward said fluid flow opening at a spacing away from said fluid flow opening.

11. The paint application system according to claim 10, wherein said stop member comprises a pin extending coaxially in said fluid flow opening and protruding coaxially into said chamber.

12. The paint application system according to claim 1, wherein said shuttle element comprises a cleaner swab having a maximum outer diameter substantially matching an inner diameter of a portion of said paint line extending between said first and second receiver stations.

13. The paint application system according to claim 12, wherein said cleaner swab has a substantially cylindrical body with two circular rims protruding radially outwardly from said body around a circumference thereof respectively at two opposite ends thereof, and wherein said maximum outer diameter is an outer diameter of said circular rims.

14. The paint application system according to claim 13, wherein said cleaner swab comprises a metal core and a plastic outer casing around said metal core, wherein at least said circular rims are formed in said plastic outer casing.

15. The paint application system according to claim 12, wherein said cleaner swab comprises a metal core and a plastic outer casing around said metal core.

16. The paint application system according to claim 12, wherein said cleaner swab at least partly consists of a polyoxymethylene plastic material.

17. The paint application system according to claim 1, wherein said connector arrangement is incorporated into said first receiver station.

18. The paint application system according to claim 1, further comprising an auxiliary medium line connected to said connector arrangement and adapted to supply said auxiliary medium.

19. The paint application system according to claim 18, wherein said auxiliary medium line is further connected to a source of pressurized air and to a source of flushing liquid, and wherein said auxiliary medium selectively comprises at least one of said pressurized air and said flushing liquid.

20. A method of using a paint application system including a paint switching device connected to a first paint container containing a first paint and to a second paint container containing a second paint different from said first paint, a paint applicator, a paint line connecting said paint switching device and said paint applicator, and a shuttle element arranged to be movable back and forth in said paint line, said method comprising the following steps:

a) flowing said first paint from said first paint container through said paint line to said paint applicator in a forward flow direction, and then ceasing said flowing of said first paint;

b) moving said shuttle element through said paint line in a return direction from said paint applicator toward said paint switching device and thereby pushing at least a predominant portion of said first paint remaining in said paint line after said step a) back into said first paint container; and

c) flowing said second paint from said second paint container through said paint line to said paint applicator in said forward flow direction.

21. The method according to claim 20, wherein said step b) comprises forcefully causing said moving of said shuttle element and said pushing of at least a predominant portion of said first paint back into said first paint container by introducing an auxiliary medium selected from a flushing liquid and pressurized air into said paint line and pushing said shuttle element using said auxiliary medium.

22. The method according to claim 20, further comprising using said shuttle element to trigger the release of a signal indicating the arrival of said shuttle element at a particular location.

23. The method according to claim 21, further comprising, between said steps b) and c),

a first additional step of causing a residual amount of said first paint still present in said paint line after said step b) to flow in said return direction through a drain line and into a drain container, using said auxiliary medium, and then

a second additional step of flushing out said paint line completely through to said paint applicator in said forward flow direction using a flushing medium and pulsed pressurized air, and then blowing out said paint line using only pressurized air.

24. The method according to claim 20, wherein said paint application system further includes a receiver station interposed in said paint line adjacent said paint applicator, wherein said step a) of flowing said first paint in said forward flow direction comprises supplying said first paint under pressure so as to flow said first paint around and past said shuttle element to said paint applicator with said shuttle element located and remaining in said receiver station, and wherein said step c) of flowing said second paint in said forward flow direction comprises supplying said second paint under pressure so as to flow said second paint around and past said shuttle element to said paint applicator with said shuttle element located and remaining in said receiver station.

25. The method according to claim 20, wherein said step a) further comprises continuing to supply said first paint from said first paint container an entire time while emitting said first paint from said paint applicator, and wherein said ceasing of said flowing of said first paint comprises stopping said emitting of said first paint from said paint applicator.

26. A paint application system comprising:

a paint supply switching device including at least one paint supply line;

a paint applicator;

a paint line connecting said paint supply switching device to said paint applicator;

first and second receiver stations interposed in said paint line, with said first receiver station adjacent said paint applicator and said second receiver station adjacent said paint supply switching device;

a shuttle element arranged to be received in and movable through said paint line between said first and second receiver stations; and

a connector arrangement that is incorporated into said first receiver station, connected to said paint line at said first receiver station, and adapted to supply an auxiliary medium into said paint line at said first receiver station.