Magnetic element temperature sensors

• US 8,251,581 B2
• Filed: 06/22/2010
• Issued: 08/28/2012
• Est. Priority Date: 05/09/2006
• Status: Active Grant

• Current Assignee: TSI Technolocies, LLC
• Original Assignee: TSI Technolocies, LLC
• Inventors: Clothier, Brian L., Abbett, Edwin T.
• Primary Examiner(s): Verbitsky, Gail
• Application Number:
  US12/821,078
• Publication Number:
  US 20100322283A1
• Time in Patent Office: 798 Days
• Field of Search: 374/120, 374/100, 374/176, 374/166, 374/183, 374/137, 374/29, 374117-119, 374/177, 219/600, 219/635.9, 219/494, 324/219, 324224-226, 324/228, 324/244, 324/260, 324/263, 148566-568, 422/119, 422/121, 422/125, 116/216
• US Class Current: 374/163
• CPC Class Codes: G01K 7/36 using magnetic elements, e.g. magnets, coils magnetic elements per se H01F
• CPC Class Codes: H05B 2213/06 Cook-top or cookware capable of communicating with each other
• CPC Class Codes: H05B 6/062 for cooking plates or the like

Abstract

The temperature sensors (26,64,96) preferably include a plurality of individual, magnetically susceptible temperature sensor elements (28-34,66,92), as well as optional magnetic field-responsive data elements (38,40,20) adapted for attachment to object (44) or to a substrate (82) in turn attached to object (44). The temperature sensor elements (28-34,66,92) preferably have magnetic bodies (22,70) exhibiting a re-magnetization response under the influence of an applied alternating magnetic field, which is different below and above a set point temperature, normally the Curie temperature of the magnetic body (22) or an adjacent sheath (74,94). The temperature sensors (26,64,96) are used in conjunction with a detector (46) operable to generate a magnetic field of magnitude sufficient to cause re-magnetization responses of the temperature sensor elements (28-34,66,92) and optional data elements (38,40,20), to detect such responses, and to use the detected responses to determine the temperature of object (44) by means of a decoding algorithm. The temperature sensors (26,64,96) can be used in closed-loop heating systems (98) capable of controlling the heating of an object (114).

Claims

1. A temperature sensor configured to be placed in thermal contact with an object in order sense the temperature of the object, said sensor comprising a plurality of magnetically susceptible sensor elements each in the form of an elongated, metallic wire or thin strip, each of said sensor elements having a different set point temperature below about 400°

C. and each being operable to individually generate a different temperature-sensitive re-magnetization response under the influence of an applied alternating magnetic field, one of said sensor elements having a higher set point temperature than another of said sensor elements, the re-magnetization response of said other sensor element at the lower set point temperature thereof being used to measure the temperature of said one sensor element.

2. The sensor of claim 1, each of said sensor element set point temperatures being the respective Curie temperature of each sensor element.

3. The sensor of claim 1, each of said sensor elements being amorphous.

4. The sensor of claim 1, each of said sensor elements being nanocrystalline.

5. The sensor of claim 1, each of said sensor elements having a maximum cross-sectional dimension of up to about 100 micrometers.

6. The sensor of claim 1, said each of said sensor elements formed of an alloy selected from the group consisting from Fe-based alloys, Co-based alloys, and mixtures thereof.

7. The sensor of claim 6, said alloy having chromium therein.

8. The sensor of claim 1, each of said sensor elements having a surrounding glass coating.

9. The sensor of claim 1, there being a ferromagnetic sheath adjacent said sensor elements.

10. The sensor of claim 9, said sheath surrounding said sensor elements.

11. The sensor of claim 9, said sheath disposed at least partially about said sensor elements and in spaced relationship thereto.

12. The sensor of claim 1, each of said sensor elements having a coercivity less than 10 A/m, a relative magnetic permeability above 20,000, a magnetostriction substantially 0 or of slightly positive value, and a large Barkhausen discontinuity.

13. The sensor of claim 1, said sensor elements being located in side-by-side juxtaposition.

14. The sensor of claim 1, each of said plurality of sensor elements having a temperature-sensitive re-magnetization response which is:

(1) correlated with the temperature of said object;

(2) defined by at least one short, detectible pulse of magnetic field perturbation of defined duration;

(3) and different below and above at least one set point temperature below about 400°

C.