Tube for the electrostatic coating of workpieces

• US 20050098223A1
• Filed: 08/27/2003
• Published: 05/12/2005
• Est. Priority Date: 08/28/2002
• Status: Active Grant

• Current Assignee: Durr Systems Incorporated (Durr AG)
• Original Assignee: Durr Systems Incorporated (Durr AG)
• Inventors: Martin, Herbert, Stiegler, Martin
• Granted Patent: US 6,986,366 B2
• Time in Patent Office: Days
• US Class Current: 138/98
• CPC Class Codes: B05B 12/14 for supplying a selected one of a plurality of liquids or other fluent materials or several in selected proportions to a spray apparatus, e.g. to a single spray outlet
• CPC Class Codes: B05B 12/1481 comprising pigs, i.e. movable elements sealingly received in supply pipes, for separating different fluids, e.g. liquid coating materials from solvent or air cleaning pipes with pigs B08B9/0557, pigs per se F16L55/26
• CPC Class Codes: B05B 5/1608 the liquid or other fluent material being electrically conductive
• CPC Class Codes: B05B 5/1616 and the arrangement comprising means for insulating a grounded material source from high voltage applied to the material
• CPC Class Codes: F16L 11/12 with arrangements for particular purposes, e.g. specially profiled, with protecting layer, heated, electrically conducting F16L11/11 takes precedence
• CPC Class Codes: Y10T 428/1393 Multilayer [continuous layer]

Abstract

For the pig delivery of the coating material at high voltage in a system for electrostatic mass-production coating of workpieces in the vicinity of grounded parts of the system, a multi-layer tube is provided, whose innermost layer forms the piggable inner wall, while a second layer consists of a high-voltage-resistant isolation material and is surrounded by a protective outer layer.

Claims

1. (canceled).

12. The tube according to claim 1, wherein said second layer is surrounded by a protective layer positioned adjacent said second layer thereby protecting said second layer from damage.

13. The tube according to claim 1, wherein said second layer comprises two sub-layers.

14. The tube according to claim 1, wherein said second layer provides electrical resistance of at least about 30 kV/mm.

15. The tube according to claim 1, wherein said first layer comprises perfluoroalkoxy polymers.

16. The tube according to claim 1, comprising an isolation layer formed from low-density polyethylene.

17. The tube according to claim 1, wherein said protective layer comprises polyurethane.

2. (canceled).

3. (canceled).

4. (canceled).

5. (canceled).

6. (canceled).

7. (canceled).

8. (canceled).

19. A method according to claim 8, comprising the step of extruding a protective layer over said isolation layer thereby protecting said isolation layer from damage.

9. (canceled).

10. (canceled).

11. A tube for the transport of a flowable material, comprising a first layer having an inner wall with piggable properties for facilitating the transfer of a pig through said tube thereby moving the flowable material through said tube and a second layer providing at least one of isolation material for hihg-voltage resistance and material providing additional functionality to said tube.

18. A method for producing a piggable tube having at least one isolation layer surrounding a piggable inner layer comprising producing said piggable inner layer and extruding an isolation layer over said piggable inner layer.