Smart susceptor radiant heater

• US 9,635,715 B1
• Filed: 05/08/2013
• Issued: 04/25/2017
• Est. Priority Date: 05/08/2013
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Miller, Robert James, Matsen, Marc R., Rawlings, Diane C.
• Primary Examiner(s): Laflame, Jr., Michael
• Application Number:
  US13/889,657
• Time in Patent Office: 1,448 Days
• Field of Search: 219603, 219618-619, 219634, 219635, 219638, 219660-665, 219671
• CPC Class Codes: H05B 2206/023 using the curie point of the material in which heating current is being generated to control the heating temperature
• CPC Class Codes: H05B 6/105 using a susceptor

Abstract

A radiant heater having a ferromagnetic element includes a high emissivity surface and an induction coil operatively coupled with the ferromagnetic element. The induction coil may be energized to create eddy currents heating the ferromagnetic element until the element reaches its Curie temperature. At the Curie temperature the ferromagnetic element becomes substantially nonmagnetic and the temperature of the element remains relatively constant. The high emissivity surface of the heater provides a substantially uniform radiant heat to an object in close proximity to the high emissivity surface. The object may be thermally coupled with the high emissivity surface of the radiant heater. The radiant heater having a high emissivity surface may be used to heat temperature sensitive objects such as thin films. Multiple radiant heaters having different Curie temperatures may be used to ramp up a temperature, ramp down a temperature, or provide different temperatures required during a process.

Claims

1. A system for heating an object, the system comprising:

a matrix, having a first surface and a second surface opposite the first surface, wherein the first surface is a high emissivity surface;

a ferromagnetic element positioned within the matrix, the ferromagnetic element having a Curie temperature;

an induction coil positioned within the matrix and operatively coupled with the ferromagnetic element;

a power source in electrical communication with the induction coil, wherein application of power to the induction coil heats the ferromagnetic element and wherein the heating of the ferromagnetic element heats the matrix; and

a thermally insulating structure connected to the second surface of the matrix.

2. The system of claim 1, further comprising a sensor configured to monitor heat along the high emissivity surface and a controller connected to the sensor and the power source, wherein the controller is configured to decrease voltage from the power source as the ferromagnetic element approaches the Curie temperature.

3. The system of claim 1, further comprising a controller connected to the power source and connected a sensor configured to monitor a load of the induction coil, wherein when the load stop changing the controller reduces the application of power to the induction coil.

4. The system of claim 1, wherein the high-emissivity surface comprises a coating on the first surface.

5. The system of claim 4, wherein the coating comprises black paint or a film that includes carbon black.

6. The system of claim 1, wherein the high-emissivity surface comprises a micro-textured surface.

7. The system of claim 1, wherein the ferromagnetic element is selected from the group consisting of sheet, film, wire, composite, or combinations thereof.

8. The system of claim 1, wherein the high-emissivity surface has an emissivity higher than 0.8.

9. The system of claim 1, wherein the high-emissivity surface has an emissivity higher than 0.9.

10. The system of claim 1, further comprising at least one aperture through the matrix.

11. The system of claim 10, further comprising at least one fan configured for movement of air through the at least one aperture.

12. The system of claim 1, further comprising a feedback mechanism configured to reduce the application of power to the induction coiled when the ferromagnetic element is heated to a predetermined temperature.

13. The system of claim 12, wherein the predetermined temperature is the Curie temperature of the ferromagnetic element.

14. The system of claim 13, wherein the feedback mechanism monitors trends in electrical power applied to the induction coil.

15. The system of claim 1, wherein the high-emissivity surface is adjacent to an object to be heated.

16. The system of claim 15, wherein a distance separates the object and the high-emissivity surface.

17. The system of claim 16, further comprising a roller, wherein the object is a thin film.

18. The system of claim 1, wherein the matrix comprises a polymeric, ceramic, or non-ferromagnetic material.

19. The system of claim 1, wherein the thermally insulating structure further comprises a reflector.