Powder coating spray booth with a powder extraction system

• US 20030019425A1
• Filed: 05/15/2002
• Published: 01/30/2003
• Est. Priority Date: 10/05/2000
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Miller, Scott, Shutic, Jeffrey R., Bark, Brean, Fenik, Larry
• Granted Patent: US 6,866,717 B2
• Time in Patent Office: Days
• US Class Current: 118/309
• 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 7/1404 Arrangements for supplying particulate material
• 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

A powder spray booth includes a booth canopy wall arrangement to contain powder during a spraying operation; and a booth floor that is rotatable relative to the booth wall during a spraying operation. The floor can be rotated about an axis that is also the longitudinal axis of the spray booth. The booth may be generally cylindrical in shape with a round floor. The booth canopy and top are supported on a base frame separately from the floor. By this arrangement, the floor can be rotated relative to the booth canopy. A powder extraction apparatus in the form of a low pressure duct suspended off the floor draws up powder that has collected on the floor. The extraction duct is stationary with respect to the rotating floor during a spraying operation. The floor may also be translated along the axis of rotation between a first position in which the floor can rotate and a second position in which the floor is sealed against a lower edge of the booth canopy wall. The booth canopy and floor are made of composite materials that are very low in conductivity to minimize powder adhering to the floor and booth walls. The booth is thus easy to clean with a substantially shorter time period required for color change.

Claims

1. A powder spray booth comprising:

a booth wall arrangement to contain powder during a spraying operation; and

a booth floor that is rotatable relative to the booth wall during a spraying operation.

2. The booth of claim 1 comprising a floor rotation control for selectively starting and stopping said floor rotation.

3. The booth of claim 1 wherein said floor rotates about a floor rotation axis that is generally parallel with a longitudinal axis of said booth wall arrangement.

4. The booth of claim 3 wherein said booth wall arrangement is a generally cylindrical structure and said booth floor is generally circular.

5. The booth of claim 4 wherein said floor rotation axis is substantially collinear with a central longitudinal axis of said booth wall arrangement.

6. The booth of claim 3 wherein said booth floor is axially moveable along said floor rotation axis.

7. The booth of claim 6 wherein said floor translates between a first floor position at which said floor is rotatable about said floor rotation axis, and a second floor position at which said floor is sealed against one end of said booth wall arrangement.

8. The booth of claim 7 comprising a lifter mechanism that raises said floor to seal against a lower end of said booth wall arrangement.

9. The booth of claim 3 comprising a powder extraction apparatus disposed in said booth for removing overspray powder that accumulates on said booth floor during a spraying operation.

10. The booth of claim 9 wherein said powder extraction apparatus is mounted stationary with respect to said rotating floor.

11. The booth of claim 9 wherein said powder extraction apparatus produces an air flow that removes overspray powder from said booth floor and transfers said overspray powder to a location outside the spray booth.

12. The booth of claim 9 wherein said powder extraction apparatus uses a negative pressure induced air flow to remove powder from said booth floor.

13. The booth of claim 12 wherein said powder extraction apparatus directs pressurized air at said booth floor to remove powder from said booth floor and into said negative pressure induced air flow.

14. The booth of claim 9 wherein said powder extraction apparatus comprises an air flow duct that at one end is coupled to a low pressure source, said duct being mounted above said booth floor to create a vacuuming effect for removing powder from said booth floor when said low pressure source is operating.

15. The booth of claim 14 wherein said duct comprises side walls have air passageways therein that direct pressurized air at said booth floor.

16. The booth of claim 1 wherein said booth comprises low conductivity composite materials.

17. The booth of claim 9 wherein said powder extraction apparatus transfers powder overspray to a powder recovery system outside said powder booth.

18. The booth of claim 17 wherein said powder recovery system comprises a cyclone that generates a negative air pressure within said powder extraction apparatus to remove powder overspray from said booth floor.

19. The booth of claim 7 comprising an annular seal that seals a joint between said booth floor and said booth wall structure when said booth floor is in said second floor position.

20. The booth of claim 19 comprising a pressurized air source that blows powder from said seal and into the spray booth.

21. A powder spray booth comprising:

.

a booth wall structure that at least partially encloses a powder containment area;

a booth floor that is rotatable about an axis; and

a powder extraction apparatus mounted in the spray booth and stationary with respect to said rotating floor.

22. The apparatus of claim 21 comprising a floor lifter mechanism that translates said floor between first and second positions along said axis.

23. A powder spray booth comprising:

a partially enclosed booth having a wall structure and a floor; and

a powder extraction apparatus that removes powder overspray from said floor during a spraying or cleaning operation;

said floor and said powder extraction apparatus being rotatable relative to each other.

24. The booth of claim 23 wherein said floor rotates about an axis relative to said powder extraction apparatus that is stationary.

25. The booth of claim 23 wherein said powder extraction apparatus removes powder from said floor by a negative pressure induced air flow.

26. The booth of claim 25 wherein said powder extraction apparatus comprises a duct that is supported above said floor diametrically across said booth.

27. The booth of claim 26 wherein said duct lies on an axis that is non-parallel with a primary air flow path into said booth.

28. The booth of claim 23 wherein said booth wall structure is supported on a base frame separately from said floor.

29. The booth of claim 28 comprising a lifter mechanism that raises and lowers said floor relative to a lower end of said booth.

30. The booth of claim 23 wherein said powder extraction apparatus is connected to a powder collection system located outside the booth.

31. The booth of claim 30 comprising a powder feed apparatus for supplying powder to spray guns that are positioned in said booth, wherein said powder collection system comprises a powder reclaim system that returns powder overspray to said powder feed apparatus.

32. The booth of claim 31 comprising a bypass device for causing powder overspray from said extraction apparatus to bypass said reclaim system and be transferred to another powder disposal device.

33. The booth of claim 30 wherein said powder collection system comprises a powder disposal apparatus that receives powder overspray from said powder extraction apparatus.

34. A powder spraying system comprising:

a spray booth with a powder overspray collection apparatus;

a cyclone separator that receives powder overspray from the collection apparatus in a reclaim mode of operation; and

a bypass valve that operates to connect the cyclone to the powder overspray collection apparatus in a reclaim mode of operation;

said valve operating to isolate the cyclone in a non-reclaim mode of operation so that powder overspray from said collection apparatus bypasses the cyclone.

35. A bypass valve for a cyclone separator comprising:

a plenum having at least one opening in fluid communication with an outlet of the cyclone and also having an outlet opening;

and a valve element that in a first position closes said cyclone outlet and when in a second position said cyclone outlet is open to said plenum outlet.

36. A method for extracting powder from a powder spray booth, comprising the steps of:

rotating a floor of the booth about a longitudinal axis of the booth during a spraying operation; and

using a low pressure induced air flow to draw powder overspray off of the floor and extract the powder to a location outside the spray booth.

37. The method of claim 36 comprising the step of axially moving the floor along said axis of rotation to seal the floor against a booth side wall structure.

38. The method of claim 37 comprising the step of air blowing powder from the floor and walls of the booth while the floor is in its sealed position against the booth wall structure.

39. The method of claim 36 wherein said induced air flow is also used as powder containment air within the booth.

40. The method of claim 36 wherein powder overspray is drawn into a duct by said air flow, said duct being stationary with respect to said rotating floor.

41. The method of claim 40 comprising the step of using said duct as an ion collector.

42. A spray booth comprising:

a non-conductive floor and canopy structure;

a powder overspray extraction duct disposed near said floor and comprising material that collect ions from electrostatic spray guns in the booth during a spraying operation.

43. The booth of claim 42 wherein said duct is stationary relative to said canopy and said floor is rotatable relative to said canopy about a longitudinal axis of the booth.

44. A powder spray booth comprising:

a canopy having a vertically extending wall portion, a floor and a ceiling;

said canopy defining a partially enclosed powder spraying area;

said wall arrangement having at least one substantial opening therein for containment air flow into an upper region of said spraying area; and

a low pressure source near said floor and extending across said floor at a non-parallel angle to a primary flow direction of said containment air;

wherein containment air flows into said booth and at least partially turns to an outer region of said spraying area and descends down to said low pressure source.

45. The booth of claim 44 wherein said canopy is generally cylindrical and said low pressure source comprises a duct that extends diametrically across said floor.

46. The booth of claim 45 wherein containment air flows down and around said outer region of said spraying area to contain powder overspray within said canopy with a central portion of said spraying area having relatively low air flow.

48. The spray booth of claim 46 wherein said floor is rotatable relative to said canopy.

47. A spray booth comprising:

a canopy and a floor;

said canopy being supported above said floor and separate therefrom.

49. The spray booth of claim 47 wherein said canopy comprises non-conductive self-supporting composite material.

50. The spray booth of claim 49 comprising a frame;

said floor and said canopy being independently supported on said frame.

51. The spray booth of claim 50 wherein a hanging knee structure supports said canopy above said floor.

52. The spray booth of claim 47 wherein said floor is translatable from a lowered to a raised position;

said floor being in contact with said canopy when in said raised position, and spaced from said canopy when in said lowered position.

53. A powder spray booth, comprising:

a floor;

said floor having a central hub;

a drive shaft; and

a connection between said drive shaft and said hub to rotate said floor about said hub during a spraying operation.

54. The booth of claim 53 wherein said floor is substantially round.

55. The booth of claim 54 wherein said connection permits translational and rotational movement of said floor.

56. The booth of claim 55 wherein said connection comprises a ball spline.

57. The booth of claim 53 comprising a motor that turns said drive shaft to rotate said floor;

and a lifter mechanism that raises and lowers said floor.

58. A powder spray booth comprising:

a canopy and a floor; and

a powder extraction duct that extends across said floor;

said extraction duct being supported above said floor at first and second ends of said duct;

said duct and floor having a gap therebetween along a length of said duct.

59. The booth of claim 58 wherein said gap tapers at an angle such that said gap is greater at one end of said duct than at an opposite end of said duct.

60. The booth of claim 59 wherein said duct is connected at said one end to a low pressure source to draw air into said duct near said floor.

61. The booth of claim 58 wherein said duct comprises electrically conductive and non-conductive portions.

62. The booth of claim 61 wherein said duct comprises a cover portion and a skirt portion;

said cover portion being non-conductive.

63. The booth of claim 62 wherein said skirt portion comprises a plurality of air holes that direct pressurized air against said floor to dislodge material that has alighted on said floor.

64. A powder spray booth comprising:

a non-conductive floor and canopy structure;

a powder overspray extraction duct disposed near said floor and comprising material that collect ions from electrostatic spray guns in the booth during a spraying operation;

said duct comprising composite non-conductive materials, wherein said non-conductive portion is a rounded cover for said duct.

65. The booth of claim 64 wherein said cover is formed in two pieces lengthwise along said duct, with each cover piece being hinged at an end thereof.

66. The booth of claim 64 wherein said cover is formed in two pieces lengthwise along said duct, with each cover piece being hinged at a lengthwise edged thereof.

67. An extraction duct for a powder spray booth, comprising:

an inner layer comprising a conductive material;

an outer layer comprising a non-conductive material;

said inner and outer layers having conforming contours and supported to form a structure having a space between said inner and outer layers.

68. The duct of claim 67 wherein comprising a non-conductive low density filler material disposed within said space.

69. The duct of claim 68 wherein said filler material comprises low density, closed cell structural foam.

70. The duct of claim 67 wherein said structure comprises two complementary longitudinal halves forming a cover.

71. The duct of claim 70 wherein said cover is hinged to a lower skirt structure.

72. The duct of claim 67 comprising a number of support ribs disposed between said inner and outer layers.

73. A powder spray booth comprising:

a canopy and a floor; and

a powder extraction duct that extends partially across said floor.

74. The booth of claim 73 wherein said duct extends about halfway across said floor.

75. The booth of claim 74 wherein said duct is supported at one end in a cantilever manner.

76. The booth of claim 73 wherein said extraction duct being supported above said floor at one end of said duct;

said duct and floor having a gap therebetween along a length of said duct.

77. The booth of claim 76 wherein said duct is hinged to said cyclone inlet duct.

78. The booth of claim 76 wherein said gap varies in size along said duct length.

79. The booth of claim 76 wherein said duct has a first end open to said booth interior and an opposite end coupled to a powder cyclone system.

80. The booth of claim 79 wherein said powder extraction system comprises a cyclone.

81. A powder spray booth comprising:

a canopy including a ceiling and a floor;

said ceiling including a conveyor slot that extends through at least a portion thereof; and

an air manifold disposed with respect to said conveyor slot to direct a flow of air downward through said conveyor slot to prevent powder from escaping through said conveyor slot.

82. The booth of claim 81 wherein said air manifold comprises a pair of elongated passageways each disposed on a respective side of said conveyor slot, with air jets formed therein to direct air towards said booth interior.

83. The booth of claim 81 comprising a source of pressurized air coupled to said air manifold.

84. A method for preventing powder from escaping through a conveyor slot in a spray booth canopy roof, comprising:

directing pressurized air towards the booth interior proximate the conveyor slot to draw air into said booth through said conveyor slot.

85. A powder spray booth comprising:

a canopy including a ceiling and a floor; and

an air manifold disposed with respect to said floor to direct a flow of air across said floor.

86. The booth of claim 85 wherein said air manifold comprises at least one elongated passageway disposed on a side of said floor, with air jets formed therein to direct air across said floor.

87. The booth of claim 85 comprising a source of pressurized air coupled to said air manifold.

88. The booth of claim 85 wherein said air jets produce a laminar air flow across said floor.