Dense phase powder coating system for containers

Patent metadata

Field	Value
Publication number	US-9027506-B2
Application number	US-201113098640-A
Country	US
Kind code	B2
Filing date	May 2, 2011
Priority date	May 2, 2011
Publication date	May 12, 2015
Grant date	May 12, 2015

Abstract

A dense phase powder coating system includes a powder supply, dense phase pump, a spray gun and a diverter valve that can be used to select between conveying powder to the spray gun or circulating the powder back to the powder supply. The diverter valve may include two pneumatically actuate valve members. In one embodiment, the powder spray gun applies powder coating material to inside surfaces of a tubular container. A spray nozzle concept also is presented having a nozzle body with a conical deflector. The spray nozzle provides an uninterrupted flow between spray nozzle outlet holes and a deflector surface. The deflector may be integrally machined with the nozzle body to provide a one piece spray nozzle.

First claim

We claim:

1. Powder coating system, comprising:
a supply of powder coating material,
a powder spray gun comprising a gun housing and a spray nozzle that can be mounted on said powder spray gun housing,
a pump, said pump comprising a pump chamber comprising an interior volume, a pump inlet valve and a pump outlet valve to control flow of powder coating material into and out of said pump chamber, said pump drawing powder coating material from said supply into said pump chamber when said pump inlet valve is open and said pump outlet valve is closed, and pushing powder coating material out of said pump chamber to said spray gun when said pump outlet valve is open and said pump inlet valve is closed, and
a diverter valve disposed between said pump outlet valve and a powder inlet of said spray gun, said diverter valve comprising a diverter valve powder inlet for receiving powder coating material from said pump outlet valve, a first selectable diverter valve outlet that forms part of a first powder flow path from said diverter valve powder inlet to said powder inlet of said spray gun, and a second selectable diverter valve outlet that forms part of a second powder flow path,
said second powder flow path being in fluid communication with said supply of powder coating material such that said second powder flow path forms a closed circulating loop from said pump to said supply of powder coating material when said second selectable diverter valve outlet is selected,
an air inlet between said diverter valve powder inlet and an outlet of said spray nozzle to add air to said powder coating material before said powder coating material exits said spray nozzle,
said diverter valve comprising an expandable member that blocks at least one of said first powder flow path and said second powder flow path in response to applied air pressure.

2. The powder coating system of claim 1 wherein said air inlet is an inlet to said diverter valve.

3. The powder coating system of claim 2 wherein said air inlet is disposed in said diverter valve to add air to said first powder flow path before powder coating material exits said diverter valve.

4. The powder coating system of claim 1 wherein said diverter valve comprises a second expandable member that in response to applied air pressure blocks the other of said at least one of said first powder flow path and said second powder flow path.

5. The powder coating system of claim 4 wherein said first expandable member and said second expandable member operate mutually exclusively of each other.

6. The powder coating system of claim 1 wherein said spray nozzle comprises a partially hollow cylindrical body, a first open end of said body for receiving a flow of powder coating material and an opposite end of said body comprising an end surface having a plurality of openings through which powder coating material flows from said first end and exits said body, and a deflector surface outside of said cylindrical body and joined with said end surface.

7. The powder coating system of claim 6 wherein said end surface is spaced from said deflector surface by a continuous groove.

8. The powder coating system of claim 6 wherein said deflector surface comprises a frusto-conical surface that tapers outwardly to deflect powder coating material flowing from said openings.

9. The powder coating system of claim 8 wherein said frusto-conical surface joins said end surface with lands between adjacent pairs of said openings.

10. The powder coating system of claim 6 wherein said deflector surface and said end surface are integral with each other.

11. The powder coating system of claim 1 wherein said pump chamber is defined by an interior volume of a gas permeable filter member.

12. The powder coating system of claim 1 wherein selection of said second selectable diverter valve outlet blocks said first powder flow path.

13. The powder coating system of claim 1 wherein said powder spray gun applies powder coating material to inside surfaces of a tubular container.

14. The powder coating system of claim 13 comprising an overspray collection hood and a powder overspray recovery system.

Assignees

• Fulkerson Terrence M
• Mather Brian D
• Nordson Corp

Inventors

• Fulkerson Terrence M
• Mather Brian D

Classifications

• B05B1/14 Primary

  with multiple outlet openings (B05B1/02, B05B1/26 take precedence); with strainers in or outside the outlet opening · CPC title

• B05B5/1683

  specially adapted for particulate materials · CPC title

• B05B1/3093 Primary

  Recirculation valves, i.e. the valve element opens a passage to the nozzle and simultaneously closes at least partially a return passage the feeding means · CPC title

• B05B15/0412

  Operations & Transport · mapped topic

• B05B5/032

  for spraying particulate materials · CPC title