DENSE PHASE OR DILUTE PHASE DELIVERY THROUGH A POWDER GUN

• US 20150190823A1
• Filed: 03/11/2013
• Published: 07/09/2015
• Est. Priority Date: 07/16/2012
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Mather, Brian D., Fulkerson, Terrence M., Becker, Benjamin J., Loparo, Thomas, Riley, Michael F.
• Granted Patent: US 9,849,474 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B05B 5/032 for spraying particulate materials
• CPC Class Codes: B05B 5/1683 specially adapted for particulate materials
• CPC Class Codes: B05B 7/1413 Apparatus to be carried on or by a person, e.g. by hand; Apparatus comprising a container fixed to the discharge device
• 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: B05B 7/1486 for spraying particulate material in dry state

Abstract

A selectively configurable spray gun may include a gun body comprising a selectable forward section and a rearward section. The rearward section may be connected with either of two or more selectable forward sections so as to selectively configure the spray gun to operate either with a dense phase powder supply configuration or a with dilute phase powder supply configuration. The rearward section may include a selectable powder flow path that is connectable at an inlet end to a source of dense phase powder and at an outlet end to a selectable spray nozzle in the selectable forward section that may optionally include a diffuser. An adapter may be used to connect the rearward section with a selectable spray nozzle or air cap. A manual spray gun embodiment is also presented. A selectively configurable spray gun for use with a dense phase powder supply may include a smaller diameter powder tube that extends through a larger diameter powder tube.

Claims

1. A spray gun that can be selectively configured to operate with a Venturi pump or a dense phase powder pump, comprising:

a gun body comprising a selectable forward section and a rearward section, said selectable forward section comprising a selectable spray nozzle,

a selectable powder flow path comprising an inlet end and an outlet end, wherein powder coating material can flow from said inlet end to said outlet end and from said outlet end to said selectable spray nozzle, said selectable powder flow path comprising a constant cross-sectional area from said powder flow path inlet end to said powder flow path outlet end,

said rearward section being joinable with either of two selectable forward sections so as to form either of two selectable spray gun configurations,

said first selectable spray gun configuration comprising a first selectable spray nozzle and a first selectable powder flow path, said first selectable powder flow path comprises a first cross-sectional area,

said second selectable spray gun configuration comprising a second selectable spray nozzle and a second selectable powder flow path, said second selectable powder flow path comprises a second cross-sectional area.

said first cross-sectional area being different from said second cross-sectional area.

2. The spray gun of claim 1 wherein said first cross-sectional area is smaller than said second cross-sectional area.

3. The spray gun of claim 2 wherein said first selectable powder flow path comprises a first selectable powder tube that is adapted to receive powder coating material from a dense phase pump when the spray gun is configured in said first selectable spray gun configuration.

4. The spray gun of claim 1 wherein said first selectable spray nozzle comprises a member for adding air to powder coating material flowing into said first selectable spray nozzle.

5. The spray gun of claim 3 wherein said second selectable powder flow path comprises a second selectable powder tube that is adapted to receive powder coating material from a dilute phase pump when the spray gun is configured in said second selectable spray gun configuration.

6. The spray gun of claim 5 wherein said first selectable powder tube extends through said second selectable powder tube when the spray gun is configured in said first selectable spray gun configuration.

7. The spray gun of claim 1 wherein said first selectable spray nozzle supports an electrode having an electrode tip that can be positioned outside said first selectable spray nozzle.

8. The spray gun of claim 1 wherein said second selectable spray nozzle supports an electrode having an electrode tip that can be positioned inside said second selectable spray nozzle.

9. The spray gun of claim 4 wherein said member comprises an expansion chamber wherein air can flow through a wall of said expansion chamber to mix with powder coating material that enters said expansion chamber from said first selectable powder flow path.

10. The spray nozzle of claim 9 wherein said expansion chamber comprises a frusto-conical air diffuser.

11. The spray nozzle of claim 10 wherein said air diffuser comprises an inlet end having a cross-sectional area that is the same as said first cross-sectional area.

12. The spray gun of claim 1 wherein said gun body comprises a handle that is manually held during a coating operation.

13. The spray gun of claim 1 in combination with a dense phase pump comprising a pump chamber disposed in a pressure chamber, first and second valves for controlling the application of suction and pressure to said pressure chamber to draw powder coating material into said pump chamber and push powder coating material out of said pump chamber, and third and fourth valves to control inlet and outlet of powder coating material to the pump chamber;

said dense phase pump supplying powder coating material to said spray gun through a first selectable powder hose having said first cross-sectional area when the spray gun is configured for said first selectable spray gun configuration.

14. The spray gun of claim 1 wherein said second selectable powder flow path comprises a powder tube that is adapted to receive powder from a Venturi pump.

15. A spray gun that can be selectively configured to operate with a Venturi pump or a dense phase powder pump, comprising:

a gun body comprising a forward section and a rearward section, said forward section comprising a selectable spray nozzle,

said rearward section comprising a powder flow path that is connectable at an inlet end to a powder coating material pump and at an outlet end to said selectable spray nozzle,

a selectable powder flow path comprising a constant cross-sectional area from said powder flow path inlet end to said powder flow path outlet end,

said rearward section being joinable with either of two selectable spray nozzles so as to form either of two selectable spray gun configurations,

said first selectable spray gun configuration comprising a first selectable spray nozzle and a first selectable powder flow path, said first selectable powder flow path comprises a first cross-sectional area, and an adapter assembly to connect said rearward section and said first selectable spray nozzle,

said second selectable spray gun configuration comprising a second selectable spray nozzle and a second selectable powder flow path, said second selectable powder flow path comprises a second cross-sectional area,

said first cross-sectional area being different from said second cross-sectional area.

16. The spray gun of claim 15 wherein when the spray gun is in said first spray gun configuration, said first selectable spray nozzle comprises a diffuser for adding air to powder coating material when powder coating material is flowing through said first selectable nozzle.

17. (canceled)

18. An automatic powder coating material spray gun, comprising:

a gun body having a forward end and a rearward end, said forward end comprising a spray nozzle;

said spray nozzle comprising an air diffuser for adding air to powder coating material when powder coating material is flowing through said spray nozzle,

a powder flow path extending through said spray gun from said rearward end to said forward end,

said powder flow path comprising a first powder tube that is adapted to receive powder from a dense phase pump,

said gun body comprising a second powder tube of larger cross-sectional area than said first powder tube, said first powder tube extending through said second powder tube.

19. The spray gun of claim 18 further comprising an electrode connectable to a source of electrical energy, said electrode being adapted to apply an electrostatic charge to powder coating material during a coating operation, said electrode comprising an electrode tip that can be positioned outside of said spray nozzle.

20. The spray gun of claim 18 wherein said powder tube receives powder from a dense phase powder pump, said dense phase powder pump having a pump chamber, said pump chamber having an inlet valve and an outlet valve, said inlet valve having an open condition and a closed condition and said outlet valve having an open condition and a closed condition.

21-22. -22. (canceled)

23. A manual powder coating material spray gun, comprising:

a gun body comprising handle and a barrel;

said gun body comprising a forward end and a handle end, said forward end comprising a spray nozzle;

said spray nozzle comprising an air diffuser for adding air to powder coating material when powder coating material is flowing through said spray nozzle,

a powder flow path extending through said spray gun from said handle end to said forward end,

said powder flow path comprising a first powder tube that is adapted to receive powder from a dense phase pump,

said gun body comprising a second powder tube of larger cross-sectional area than said first powder tube, said first powder tube extending through said second powder tube.

24. The manual powder coating material spray gun of claim 23 further comprising an electrode connectable to a source of electrical energy, said electrode being adapted to apply an electrostatic charge to powder coating material during a coating operation, said electrode comprising an electrode tip that can be positioned outside of said spray nozzle.

25. A spray gun for use with a dense phase powder supply, comprising:

a forward section that is adapted to spray a diluted powder flow, and a rearward section having a powder inlet that is connectable to a dense phase powder supply,

a first powder tube having a first cross-sectional area that extends through a second powder tube having a second cross-sectional area that is larger than the first cross-sectional area.

26. The spray gun of claim 25 wherein when said smaller diameter powder tube is connectable to the dense phase powder supply, a dense phase powder flow passes through said smaller cross-sectional area powder tube to a spray nozzle or an air cap.

27. The spray gun of claim 25 wherein the spray gun comprises a manual spray gun.

28. The spray gun of claim 25 wherein said forward section includes a diffuser for adding dilution air to a dense phase powder flow through said forward section.

29. The spray gun of claim 26 wherein when said smaller diameter powder tube is removed from the spray gun, said larger diameter powder tube is connectable to a dilute phase powder supply and a different forward section is installed in place of said forward section, with said second forward section being adapted to spray a diluted powder flow from a dilute phase powder supply.