ELECTROMAGNETIC CONVEYOR

• US 20170252784A1
• Filed: 10/01/2015
• Published: 09/07/2017
• Est. Priority Date: 10/29/2014
• Status: Active Application

• Current Assignee: Laitram LLC
• Original Assignee: Laitram LLC
• Inventors: Ragan, Bryant G.
• Granted Patent: US 10,273,095 B2
• Time in Patent Office: Days
• CPC Class Codes: B08B 2203/0229 Suction chambers for aspirating the sprayed liquid
• CPC Class Codes: B08B 3/022 Cleaning travelling work B08B3/042 takes precedence
• CPC Class Codes: B08B 9/0813 by the force of jets or sprays
• CPC Class Codes: B08B 9/205 Conveying containers to or from the cleaning machines
• CPC Class Codes: B08B 9/36 the apparatus cleaning by using brushes
• CPC Class Codes: B08B 9/42 the apparatus being characterised by means for conveying or carrying containers therethrough
• CPC Class Codes: B60L 13/03 Electric propulsion by linear motors
• CPC Class Codes: B60L 13/10 Combination of electric propulsion and magnetic suspension or levitation
• CPC Class Codes: B65G 54/02 electrostatic, electric, or magnetic
• CPC Class Codes: H05B 6/101 for local heating of metal pieces

Abstract

An electromagnetic propulsion system for electrically conductive articles, such as aluminum beverage cans. Currents in coils disposed along a passageway induce currents in aluminum cans in the passageway. The electromagnetic fields produced by the coil currents and the eddy currents in the cans interact to produce forces that propel the cans along the passageway. A coil drive supplies the coils with a low-frequency current to propel the cans and a high-frequency current to heat the cans. The coils are arranged as solenoids encircling the passageway or as planar arrays bracketing the passageway. Besides being used to propel aluminum cans, the coils can be used to spin cans. The electromagnetic propulsion systems are shown in can washers and dryers.

Claims

1. A propulsion system for electrically conductive articles comprising:

a passageway extending in length from a first end to an opposite second end and having an entrance at the first end for admitting electrically conductive articles into the passageway and an exit at the second end though which the electrically conductive articles leave the passageway;

primary coils adjacent to the passageway along its length;

a coil drive providing currents in the primary coils that produce a primary electromagnetic field that induces currents in the electrically conductive articles in the passageway that create secondary electromagnetic fields in the electrically conductive articles that interact with the primary electromagnetic field to produce a drive force directed against the electrically conductive articles to propel them from the entrance and through the exit of the passageway.

2. A propulsion system as in claim 1 wherein the primary coils are arranged as a solenoid surrounding the passageway along its length.

3. A propulsion system as in claim 1 further comprising a hollow, elongated, nonmetallic coil form around which the primary coils are wound, the coil form having an inner wall made of a low-friction material bounding the passageway.

4. A propulsion system as in claim 3 wherein the coil form is circular in cross section.

5. A propulsion system as in claim 3 wherein the coil form is rectangular in cross section.

6. A propulsion system as in claim 5 wherein the passageway has a 180°

bend.

7. A propulsion system as in claim 5 wherein the passageway has a 180°

twist.

8. A propulsion system as in claim 1 wherein the coil drive provides the current with a first current at a first frequency primarily to propel the electrically conductive articles and a second current at a higher second frequency primarily to inductively heat the electrically conductive articles.

9. A propulsion system as in claim 1 further comprising fluid ports and wherein the passageway has openings through which the fluid ports supply fluid to wash the electrically conductive articles being propelled through the passageway.

10. A propulsion system as in claim 1 wherein the primary electromagnetic field produced by the coil drive and the primary coils is an electromagnetic flux wave traveling along the length of the passageway, the propulsion system further comprising a second set of coils arranged around the passageway to carry currents perpendicular to the currents in the primary coils that produce an electromagnetic flux wave that travels circumferentially around the passageway to cause the electrically conductive articles to rotate as they are propelled along the length of the passageway.

11. A propulsion system as in claim 1 further comprising scrubbing elements bounding the passageway to scrub the electrically conductive articles as they pass.

12. A propulsion system as in claim 1 further comprising a magnetically permeable backing surrounding the primary coils.

13. A propulsion system as in claim 1 wherein the cross-sectional area of the passageway increases monotonically from the first end to the second end.

14. A propulsion system as in claim 1 wherein the passageway has a circular cross section in a first portion extending from the first end toward the second end, a rectangular cross section in a second portion extending from the second toward the first end, and a cross section transitioning from square to rectangular in a transition portion separating the first portion from the second portion.

15. A propulsion system as in claim 14 further comprising a permanent magnet disposed outside the passageway close to one end of the longer side of the cross section of the transition portion nearer to the second portion than to the first portion.

16. A propulsion system as in claim 1 wherein the primary coils extend in length along a first side of the passageway, the propulsion system further comprising an array of permanent magnets extending in length along an opposite second side of the passageway.

17. A propulsion system as in claim 1 wherein the primary coils include a first set of coils extending in length along a first side of the passageway and a second set of coils extending in length along an opposite second side of the passageway.

18. A propulsion system as in claim 17 comprising a first coil form supporting the first set of coils and a second coil form supporting the second set of coils, wherein the first and second coils forms bound the passageway, the propulsion system further comprising a hinge joining the first coil form to the second coil form.

19. A propulsion system as in claim 17 wherein the first set of coils produces a first electromagnetic flux wave traveling along the passageway from the first end to the second end and the second set of coils produces a second electromagnetic flux wave traveling along the passageway in the opposite direction, and wherein the first and the second electromagnetic flux waves have different magnitudes to cause the electrically conductive articles to rotate as they are propelled along the passageway.

20. A propulsion system as in claim 1 wherein the electrically conductive articles are aluminum cans.

21. A propulsion system as in claim 1 wherein the coil drive is a three-phase current source and the primary coils include three-phase windings.