POWDER GUN CONFIGURABLE FOR SUPPLY FROM VENTURI OR DENSE PHASE PUMP

• US 20150053797A1
• Filed: 03/07/2013
• Published: 02/26/2015
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Fulkerson, Terrence M., Mather, Brian D., Becker, Benjamin J.
• Granted Patent: US 10,040,081 B2
• Time in Patent Office: Days
• US Class Current: 239/704
• CPC Class Codes: B05B 5/032 for spraying particulate materials
• CPC Class Codes: B05B 7/1404 Arrangements for supplying particulate material
• CPC Class Codes: B05B 7/1463 the means for supplying particulate material comprising a gas inlet for pressurising or avoiding depressurisation of a powder container

Abstract

A powder spray gun includes a powder flow path inlet and a powder flow path outlet, the powder flow path inlet being connectable in a first configuration to a dilute phase powder pump and in a second configuration to a dense phase powder pump, wherein the powder spray gun comprises a spray nozzle that is the same for the first and second configurations. The powder flow path is provided by a powder tube that extends through the gun, with the powder tube having a first diameter at an inlet portion of the spray gun and a second diameter at an outlet portion of the spray gun, with the second diameter being greater than the first diameter. The powder flow path may also include a conical transition portion, and a member for adding air to the powder flow.

Claims

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

a gun body comprising a forward section and a selectable rearward section,

said forward section comprising a spray nozzle,

a 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 spray nozzle,

said forward section being joinable with either of two selectable rearward sections,

said first selectable rearward section comprising a portion of said powder flow path and wherein said powder flow path has a constant cross-sectional area from said powder flow path inlet end to said powder flow path outlet end,

said second selectable rearward section comprising a portion of said powder flow path and wherein said portion of said powder flow path comprises a first cross-sectional area and a second cross-sectional area with a transition portion of said powder flow path joining said first cross-sectional area and said 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 second housing supports a powder tube that is adapted to receive powder coating material from a dense phase pump.

4. The spray gun of claim 3 wherein said transition portion comprises a member for adding air to powder coating material flowing into said second cross-sectional area.

5. The spray gun of claim 1 wherein said constant cross-sectional area is defined by a single piece powder tube that extends from said powder flow path inlet end to said powder flow path outlet end.

6-16. -16. (canceled)

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

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

a powder flow path extending through said gun from said rearward end to said forward end, said powder flow path having a first internal diameter; and

a transition member enclosing a conical expansion chamber, said expansion chamber having a front end and a back end, said front end having an internal diameter and said back end having an internal diameter, said front end internal diameter being larger than said back end internal diameter, said back end receiving powder from a powder supply conduit, said powder supply conduit having a second internal diameter, said second internal diameter being smaller than said first internal diameter, said front end of said expansion chamber supplying powder to said powder flow path, wherein powder coating material flows from said powder supply conduit through said expansion chamber into said powder flow path and from said powder flow path trough said spray orifice.

18. The spray gun of claim 17 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.

19. The spray gun of claim 17 wherein said powder supply conduit 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.

20. The spray gun of claim 17 wherein further comprising a diffuser member, said diffuser member adding air to powder coating material before said powder coating material flows through said powder flow path.

21. The spray gun of claim 20 wherein said diffuser member supplies powder to said expansion chamber and receives powder from said powder supply conduit.

22. A powder coating system, comprising:

an automatic powder coating material spray gun, having;

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

a powder flow path extending through said gun from said rearward end to said forward end, said powder flow path having a first internal diameter; and

a transition member enclosing a conical expansion chamber, said expansion chamber having a front end and a back end, said front end having an internal diameter and said back end having an internal diameter, said front end internal diameter being larger than said back end internal diameter, said back end receiving powder from a powder supply conduit, said powder supply conduit having a second internal diameter, said second internal diameter being smaller than said first internal diameter, said front end of said expansion chamber supplying powder to said powder flow path, wherein powder coating material flows from said powder supply conduit through said expansion chamber into said powder flow path and from said powder flow path through said spray orifice; and

a 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, wherein said powder supply conduit receives powder from a dense phase powder pump.

23. The system of claim 22 wherein said spray gun further comprises 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.

24. The system of claim 22 wherein said spray gun further comprises a diffuser member, said diffuser member adding air to powder coating material before said powder coating material flows through said powder flow path.

25. The spray gun of claim 24 wherein said diffuser member supplies powder to said expansion chamber and receives powder from said powder supply conduit.

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

a gun body having handle and a barrel;

a spray nozzle attached to a front end of said barrel of said gun body, said spray nozzle having a spray orifice;

a powder flow path within said gun body, said powder flow path extending along said barrel and having an inlet; and

a transition member enclosing a conical expansion chamber, said expansion chamber having an outlet end and an inlet end, said outlet end having an internal diameter and said inlet end having an internal diameter, said outlet end internal diameter being larger than said inlet end internal diameter, said inlet end receiving powder from a powder supply conduit, said powder supply conduit having a second internal diameter, said second internal diameter being smaller than said first internal diameter, said outlet end of said expansion chamber supplying powder to said powder flow path, wherein powder coating material flows from said powder supply conduit through said expansion chamber into said powder flow path and through said powder flow path along said barrel and through said spray orifice.

27. The spray gun of claim 26 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.

28. The spray gun of claim 26 wherein said powder supply conduit 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.

29. The spray gun of claim 26 wherein further comprising a diffuser member, said diffuser member adding air to powder coating material before said powder coating material flows through said powder flow path.

30. The spray gun of claim 26 wherein said handle of said spray gun has a bottom, and said transition member is attached to the bottom of said handle.

31. The spray gun of claim 29 wherein said handle of said spray gun has a bottom, and said diffuser member is attached to the bottom of said handle.

32. The spray gun of claim 26 wherein said powder flow path extends up through said handle and along said barrel.

33-45. -45. (canceled)