Quick change powder coating spray system

• US 20020078883A1
• Filed: 06/25/2001
• Published: 06/27/2002
• Est. Priority Date: 10/05/2000
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Schroeder, Joseph G., Turner, Herman E., Shutic, Jeffrey R., Peddie, Andrew M., Fenik, Larry R., Mancuso, David, Selic, Erich W.
• Granted Patent: US 7,325,750 B2
• Time in Patent Office: Days
• US Class Current: 118/50
• CPC Class Codes: B01D 45/14 generated by rotating vanes, discs, drums or brushes
• CPC Class Codes: B05B 14/41 by cleaning the walls of the booth
• CPC Class Codes: B05B 14/45 using cyclone separators
• CPC Class Codes: B05B 14/48 specially adapted for particulate material
• CPC Class Codes: B05B 16/25 for both automatic and manual spraying
• CPC Class Codes: B05B 16/40 Construction elements specially adapted therefor, e.g. floors, walls or ceilings ceiling elements filtering inflow of air into the booth B05B16/60; walls specially adapted for promoting separation of excess material B05B14/44
• CPC Class Codes: B05B 16/405 Partly or totally cylindrical walls; Round floors
• CPC Class Codes: B05B 16/60 Ventilation arrangements specially adapted therefor
• CPC Class Codes: B05B 7/1454 comprising means for supplying collected oversprayed particulate material spray booth with arrangements for collecting oversprayed material B05B14/40
• CPC Class Codes: B05B 7/1472 Powder extracted from a powder container in a direction substantially opposite to gravity by a suction device dipped into the powder
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Abstract

Powder overspray that is extracted from a spray booth is recovered back to a powder supply that is used to supply powder to the spray guns inside the spray booth. The powder overspray extracted from the booth is separated from the high flow air stream by a separator such as a cyclone separator. The powder falls into a transfer pan and a vacuum is used to convey the powder from the transfer pan to a vacuum receiver. The powder is then discharged to the feed hopper in the feed center. The use of a vacuum to convey powder from the cyclone to the feed center in effect permits substantially all of the powder overspray to be recovered from the spray booth directly to the feed hopper with minimal dwell or residence time within the cyclone or vacuum receiver subsystems during a spraying operation. The receiver can be rotated for easy cleaning, and the vacuum line cleaned by one or more cleaning elements drawn through the vacuum line.

Claims

1. A powder coating spray system comprising:

a spray booth that at least partially encloses a spray area in which powder overspray is produced during a spraying operation;

a powder feed apparatus that supplies powder to spray guns in said booth;

a powder extraction apparatus that removes said powder overspray from said booth and transfers said powder overspray to a first collection device; and

a vacuum source connected to said first collection device to transfer powder overspray from said first collection device to a second powder collection device, wherein said first powder collection device comprises a cyclone separator.

2. The system of claim 1 wherein said first collection device comprises a dual cyclone separator.

3. The system of claim 1 wherein said second collection device comprises a powder feed hopper in a feed center.

4. The system of claim 3 wherein said vacuum source is connected to a vacuum receiver and filter assembly that receives powder from said cyclone and supplies said cyclone-received powder to said powder feed hopper.

5. The system of claim 4 wherein said vacuum receiver is connected to said cyclone by rigid tubing;

and a cleaning device that is drawn through said tubing by said vacuum source to clean powder from said tubing.

6. The system of claim 5 wherein said cleaning device is a foam-like mass.

7. The system of claim 4 comprising a sieve and vibrator assembly disposed between said vacuum receiver and said powder feed hopper.

8. The system of claim 1 wherein said powder extraction apparatus comprises a vacuum duct disposed within said spray booth to remove powder overspray therefrom.

9. The system of claim 8 wherein said powder spray booth comprises a floor that rotates about an axis;

said vacuum duct being suspended above said floor and stationary with respect thereto to remove powder overspray from said floor as said floor rotates during a spraying operation.

10. The system of claim 8 wherein said first collection device comprises a cyclone separator;

and wherein said vacuum duct is connected to an inlet of said cyclone.

11. The system of claim 1 wherein said first collection device comprises a cyclone separator having a powder outlet opening;

and a cyclone outlet interface that receives powder from said cyclone outlet;

said interface having at least one port connected to said vacuum source to remove powder from said interface as said powder enters said interface from said cyclone.

12. The system of claim 11 wherein said vacuum source draws powder from said interface at a rate at least as fast as a rate at which powder enters said interface from said cyclone.

13. The system of claim 11 wherein said interface comprises a second port connected to a second vacuum source so that powder from said cyclone outlet bypasses said feed center.

14. The system of claim 1 wherein powder is supplied to spray guns in said booth from a hopper in said powder feed apparatus;

at least a portion of said powder being powder overspray from a spraying operation;

said powder overspray being extracted from said booth during a spraying operation, transferred to said first collection device and then back to said hopper, to produce a substantially continuous closed loop flow of powder during a spraying operation.

16. The system of claim 15 wherein said vacuum source draws powder from said interface at a rate that is at least as fast as powder enters said interface from said cyclone outlet.

17. The system of claim 15 wherein said interface is connected to outlets of two cyclones operating side by side.

18. The system of claim 15 wherein said vacuum source is connected to a vacuum receiver having an inlet, a filter and an outlet;

said receiver inlet being connected to an outlet port of said interface;

wherein powder from said interface is separated in said receiver and transferred through said receiver outlet to said collection device.

19. The system of claim 18 wherein said collection device comprises a powder feed hopper.

20. The system of claim 15 wherein said interface comprises a transfer pan in which swirling powder is received from said cyclone outlet.

21. The system of claim 20 wherein said transfer pan comprises a tubular port for connection to a vacuum line, said tubular port opening to said pan interior with a lengthened opening to facilitate powder passing into said tubular port.

22. The system of claim 21 wherein said lengthened opening has a cross-sectional area that is about the same as the cross-sectional area of said tubular port.

23. The apparatus of claim 15 wherein said collection device comprises a vacuum receiver, said receiver being rotatable about an axis to facilitate cleaning operations.

24. The apparatus of claim 15 wherein said interface is connected to said vacuum receiver by a seamless rigid tube.

26. The receiver of claim 25 wherein said canister comprises a removable cover that carries a color-specific filter thereon.

27. The receiver of claim 25 wherein said support frame comprises part of a powder feed center for a powder spraying apparatus.

29. The system of claim 28 wherein said collection device comprises a cyclone separator.

30. The system of claim 29 wherein said cyclone separator comprises two cyclones.

31. The system of claim 28 wherein said powder extraction device comprises a duct that extends over a floor of the booth and draws powder off the floor during a spraying operation.

32. The system of claim 31 wherein said floor rotates about a longitudinal axis of the booth and relative to said duct.

33. The system of claim 32 wherein the booth is generally cylindrical and the booth floor is circular.

34. The system of claim 32 wherein the booth and floor comprises very low conductivity composite material.

35. The system of claim 34 wherein the booth is self-supporting and is suspended in a cantilever manner over said floor.

36. The system of claim 34 wherein said floor is supported in a cantilever manner on a central hub.

37. The system of claim 28 wherein said vacuum device conveys powder from said collection device to a feed hopper.

38. The system of claim 37 wherein said vacuum device conveys powder from said collection device to said feed hopper via a sieve.

39. The system of claim 28 wherein said vacuum device is connected to a vacuum source;

the vacuum in said vacuum receiver being periodically interrupted to permit powder discharge from said vacuum device.

40. The system of claim 39 wherein said vacuum device comprises a discharge valve at the bottom of said vacuum device that opens under the force of gravity when said vacuum device is not under vacuum.

41. The system of claim 40 comprising an actuator that closes said discharge valve.

42. The system of claim 28 wherein said feed device comprises a powder feed hopper.

43. The system of claim 42 wherein said feed hopper is installed in a powder feed center as part of an application system.

15. A powder recovery system for a powder coating system, comprising:

a cyclone separator having a powder outlet;

a vacuum source; and

a powder extraction interface between said cyclone outlet and said vacuum source;

said interface receiving powder from said cyclone outlet;

said vacuum source transferring powder in said interface to a collection device.

25. A vacuum receiver for a powder recovery system, comprising:

a receiver canister; and

a support frame for said canister;

said canister being mounted for selected rotation about an axis to facilitate cleaning the canister.

28. A powder spraying system of the type having a spray booth and a powder feed hopper for supplying powder to a spray hopper, comprising:

a powder extraction device in said booth that conveys powder overspray from the booth to a collection device outside the booth; and

a vacuum device that conveys powder from said collection device to the feed hopper.

44. A quick change powder coating spraying system comprising:

a generally cylindrical powder spray booth comprising a canopy;

a generally circular booth floor that rotates relative to said canopy;

said canopy being suspended over said floor;

a powder overspray extraction duct disposed in said booth to draw powder from said rotating floor during a spraying operation;

a cyclone separator that receives powder from said extraction duct; and

a vacuum conveyance system for vacuum conveying powder from said cyclone separator to a powder feed hopper.

45. The system of claim 44 wherein said feed hopper is part of a powder application system for powder spraying objects inside said booth.

46. The system of claim 44 wherein powder overspray is continuously scavenged from said floor into said duct during a spraying operation.

47. The system of claim 44 wherein powder is continuously scavenged from said cyclone to a vacuum receiver during a spraying operation.

49. The method of claim 48 comprising the step of drawing powder from the booth floor into a duct using low pressure air flow into the duct.

50. The method of claim 48 comprising the step of continuously conveying powder from said collection device to a second collection device.

51. The method of claim 50 comprising the step of periodically discharging powder from said second collection device to said application system.

48. A method for quick color change in a powder spraying system of the type having a spray booth and a powder spray application system, comprising the steps of:

continuously drawing powder from said spray booth during a spraying operation;

transferring powder from said booth to a first collection device;

conveying powder from said first collection device to said application system under vacuum.

52. A powder coating application system, comprising:

a powder spray booth;

said booth comprising a canopy wall structure and a floor that is rotatable relative to said canopy wall structure;

a powder overspray extraction device for extracting powder overspray from said floor to a first collection device; and

a vacuum recovery system that conveys powder overspray from said first collection device to a powder supply.

53. The system of claim 52 wherein said first collection device comprises a cyclone separator.

54. The system of claim 52 wherein said extraction device produces a low pressure region near said floor to draw powder overspray from said floor and transfer said powder overspray outside said canopy wall structure.

55. A method for cleaning a vacuum line for a powder recovery system, comprising:

producing a vacuum in a vacuum line connected between a first powder collection device and a second powder collection device;

using said vacuum to convey powder from said first powder collection device to said second powder collection device; and

cleaning said vacuum line by passing at least one wiping element through said line under force of said vacuum.

57. The system of claim 56 wherein said spray gun comprises a powder flow path that extends in a single direction from said spray gun powder inlet to said nozzle.

58. The system of claim 57 comprising at least one pressurized air source positioned proximate said spray gun to remove powder from said spray gun housing.

59. The system of claim 56 comprising a spray booth, said spray gun being at least partly disposed in said booth during a spraying operation, and a powder overspray extraction system that extracts powder overspray from said spray booth during a spraying operation.

60. The system of claim 59 wherein said extraction system comprises a spray booth floor that rotates and an extraction device that removes powder overspray from said rotating floor.

61. The system of claim 60 wherein said extraction device produces a low pressure air flow that draws powder overspray from said floor.

56. A powder coating application system, comprising:

a powder pump having a powder inlet and a powder outlet;

a powder spray gun having a powder inlet and a nozzle; and

a powder feed hose that connects said pump powder outlet with said spray gun powder inlet;

said powder pump having a powder flow path that extends in a single direction from said powder inlet to said powder outlet.

62. In a powder coating application system, a powder overspray sieve comprising a screen for filtering powder therethrough;

said screen being removeable for a color change operation and powder color specific.

63. A powder overspray collection system, comprising:

a powder spray booth;

at least one powder spray gun disposed in said booth for spraying an object;

a powder supply for supplying powder to said spray gun;

said spray booth comprising a canopy and a floor that rotates relative to said canopy; and

a powder overspray collection system that transfers powder overspray from said spray booth to said powder supply;

said collection system comprising;

a powder overspray extraction duct that draws powder overspray from said rotating floor and transfers said powder overspray to a powder separation device; and

a vacuum source that conveys powder overspray from said separation device to said powder supply.

64. A powder coating spray system comprising:

a spray booth that at least partially encloses a spray area in which powder overspray is produced during a spraying operation;

a powder feed apparatus that supplies powder to spray guns in said booth;

a powder extraction apparatus that removes said powder overspray from said booth and transfers said powder overspray to a first collection device; and

a vacuum source connected to said first collection device to transfer continuously powder overspray from said first collection device to a second powder collection device.