MAGNETIC ELEMENT TEMPERATURE SENSORS

• US 20100006562A1
• Filed: 05/07/2007
• Published: 01/14/2010
• Est. Priority Date: 05/09/2006
• Status: Active Grant

• Current Assignee: TSI SUB LLC
• Original Assignee: Thermal Solutions Incorporated (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Clothier, Brian L.
• Granted Patent: US 8,258,441 B2
• Time in Patent Office: Days
• US Class Current: 219/494
• CPC Class Codes: G01K 1/024 for remote indication
• CPC Class Codes: G01K 2207/08 with food recipients having temperature sensing capability
• CPC Class Codes: G01K 7/36 using magnetic elements, e.g. magnets, coils magnetic elements per se H01F

Abstract

Small, low-cost wireless temperature sensors (120) are provided for sensing the temperature of servingware (121). Each temperature sensor preferably includes a substrate (124); at least one sensor element (122) positioned on the substrate; and an adhesive (126) for securing the sensor element to the substrate and for securing the temperature sensor to the servingware so that the sensor element may sense a temperature of the servingware. The temperature sensors may be used in conjunction with a reader/detector (136) operable to generate a magnetic field of magnitude sufficient to cause re-magnetization responses of the temperature sensor element and optional data elements to detect such responses, and to use the detected responses to determine the temperature of the servingware by means of a decoding algorithm. The temperature sensors can be used in closed-loop heating systems capable of controlling the heating of the servingware.

Claims

1. A temperature sensor configured to be affixed to an object in order to sense a parameter relating to a temperature of the object, the temperature sensor comprising:

a substrate;

at least one sensor element positioned on the substrate; and

an adhesive operable to secure the sensor element to the substrate and to secure the temperature sensor to the object so that the sensor element may sense the temperature parameter of the object.

2. The temperature sensor of claim 1, wherein the temperature parameter is selected from the group consisting of a temperature of the object, a desired temperature of the object, a temperature range of the object, a desired temperature range of the object, a minimum temperature of the object, a maximum temperature of the object, a heating property of the object, and the temperature of a material supported by the object.

3. The temperature sensor of claim 1, the sensor element comprising a magnetically susceptible sensor element having a re-magnetization response under the influence of an applied alternating magnetic field, the re-magnetization response defined by at least one short, detectible pulse of magnetic field perturbation of defined duration and being different below and above at least one set point temperature below about 400°

C.

4. The temperature sensor of claim 3, there being a plurality of the sensor elements positioned on the substrate, with at least certain of the sensor elements having a different set point temperature than other of the sensor elements.

5. The temperature sensor of claim 3, the set point temperature being a Curie temperature of the sensor element.

6. The temperature sensor of claim 3, the sensor element having different re-magnetization responses above and below a plurality of different set point temperatures.

7. The temperature sensor of claim 6, the plurality of different set point temperatures being below the Curie temperature of the sensor element.

8. The temperature sensor of claim 1, the sensor element comprising a metallic body.

9. The temperature sensor of claim 8, the metallic body being amorphous.

10. The temperature sensor of claim 8, the metallic body being nanocrystalline.

11. The temperature sensor of claim 8, the metallic body being in the form of an elongated wire or thin strip having a maximum cross-sectional dimension of up to about 100 μ

m.

12. The temperature sensor of claim 8, the metallic body formed of an alloy selected from the group consisting from Fe-based alloys, Co-based alloys, and mixtures thereof.

13. The temperature sensor of claim 12, the alloy having chromium therein.

14. The temperature sensor of claim 1, the sensor element comprising a metallic body with a glass coating surrounding the body.

15. The temperature sensor of claim 1, the sensor element comprising a metallic body, there being a ferromagnetic sheath adjacent the metallic body.

16. The temperature sensor of claim 1, the element comprising a metallic body 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.

17. The temperature sensor of claim 15, the element comprising a metallic body producing a characteristic re-magnetization pulse above the Curie temperature of the adjacent ferromagnetic sheath, and producing no re-magnetization pulse, or an altered re-magnetization pulse, at one or more temperatures below the Curie temperature of the adjacent ferromagnetic sheath.

18. The temperature sensor of claim 1, the substrate being formed of a material selected from the group consisting of:

a polymer film, polyethylene terephthalate (PET), polyethylene, polypropylene, cellulose, paper, and pulp-type materials.

19. The temperature sensor of claim 1, wherein the substrate is generally circular with a diameter of approximately 10-30 mm and a thickness of approximately 0.0025-0.01 inches.

20. The temperature sensor of claim 1, wherein the substrate is translucent.

21. The temperature sensor of claim 1, wherein the substrate is formed of a material that dissolves when exposed to water.

22. The temperature sensor of claim 1, wherein the adhesive is an ultraviolet light curable adhesive.

23. The temperature sensor of claim 1, further including a removable release layer positioned over the adhesive which maybe removed to expose one face of the adhesive for seeming the temperature sensor to the object.

24. The temperature sensor of claim 1, said object being servingware.

25. The temperature sensor of claim 24, said sensor oriented to measure the temperature of food placed on said servingware.

26. A temperature sensor configured to be affixed to an object in order to sense a parameter relating to a temperature of the object, the temperature sensor comprising:

at least one sensor element comprising a magnetically susceptible sensor element having a re-magnetization response under the influence of an applied alternating magnetic field, the re-magnetization response defined by at least one short, detectible pulse of magnetic field perturbation of defined duration and being different below and above at least one set point temperature below about 400°

C.; and

an adhesive operable to secure the temperature sensor to the object so that the sensor element may sense the parameter of the object.

27. The temperature sensor of claim 26, wherein the parameter is selected from the group consisting of a temperature of the object, a desired temperature of the object, a temperature range of the object, a desired temperature range of the object, a minimum temperature of the object, a maximum temperature of the object, a heating property of the object, and the temperature of material supported on the object.

28. The temperature sensor of claim 26, there being a plurality of the sensor elements, with at least certain of the sensor elements having a different set point temperature than other of the sensor elements.

29. The temperature sensor of claim 26, the set point temperature being a Curie temperature of the sensor element.

30. The temperature sensor of claim 26, the sensor element having different re-magnetization responses above and below a plurality of different set point temperatures.

31. The temperature sensor of claim 30, the plurality of different set point temperatures being below the Curie temperature of the sensor element.

32. The temperature sensor of claim 26, the sensor element comprising a metallic body.

33. The temperature sensor of claim 32, the metallic body being amorphous.

34. The temperature sensor of claim 32, the metallic body being nanocrystalline.

35. The temperature sensor of claim 32, the metallic body being in the form of an elongated wire or thin strip having a maximum cross-sectional dimension of up to about 100 μ

m.

36. The temperature sensor of claim 32, the metallic body formed of an alloy selected from the group consisting from Fe-based alloys, Co-based alloys, and mixtures thereof.

37. The temperature sensor of claim 36, the alloy having chromium therein.

38. The temperature sensor of claim 26, the sensor element comprising a metallic body with a glass coating surrounding the body.

39. The temperature sensor of claim 26, the sensor element comprising a metallic body, there being a ferromagnetic sheath adjacent the metallic body.

40. The temperature sensor of claim 26, the element comprising a metallic body 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.

41. The temperature sensor of claim 40, the element comprising a metallic body producing a characteristic re-magnetization pulse above the Curie temperature of the adjacent ferromagnetic sheath, and producing no re-magnetization pulse, or an altered re-magnetization pulse, at one or more temperatures below the Curie temperature of the adjacent ferromagnetic sheath.

42. The temperature sensor of claim 26, including a substrate, with said sensor element positioned on said substrate, said substrate being formed of a material selected from the group consisting of:

a polymer film, polyethylene terephthalate (PET), polyethylene, polypropylene, cellulose, paper, and pulp-type materials.

43. The temperature sensor of claim 42, wherein the substrate is generally circular with a diameter of approximately 10-30 mm and a thickness of approximately 0.0025-0.01 inches.

44. The temperature sensor of claim 42, wherein the substrate is translucent.

45. The temperature sensor of claim 42, wherein the substrate is formed of a material that dissolves when exposed to water.

46. The temperature sensor of claim 26, wherein the adhesive is an ultraviolet light curable adhesive.

47. The temperature sensor of claim 26, further including a removable release layer positioned over the adhesive which may be removed to expose one face of the adhesive for securing the temperature sensor to the object.

48. A method of sensing a parameter relating to the temperature of an object, the method comprising the steps of:

adhering a re-magnetizable temperature sensor to the object;

generating an alternating magnetic field in the region of the temperature sensor; and

detecting a re-magnetization response of the sensor element, and using the detected response to at least in part determine whether the temperature parameter of the object is above or below a set point temperature.

49. The temperature sensor of claim 48, the sensor element comprising a magnetically susceptible sensor element having a re-magnetization response under the influence of an applied alternating magnetic field, the re-magnetization response defined by at least one short, detectible pulse of magnetic field perturbation of defined duration and being different below and above at least one set point temperature below about 400°

C.

50. The method of claim 49, the temperature sensor having a plurality of magnetically susceptible sensor elements each having a different re-magnetization response under the influence of an applied alternating magnetic field and each re-magnetization response being different below a different set point temperature, further including the step of using the different re-magnetization responses to determine the temperature parameter of the object.

51. The method of claim 48, the detecting step comprising the steps of using a field receiving coil to detect the re-magnetization response and to generate an output signal corresponding to the detected re-magnetization response.

52. The method of claim 51, further including the step of using a signal processing unit operably coupled with the field receiving coil to receive the output signal and to determine therefrom at least the approximate temperature of the object.

53. The method of claim 52, the step of determining the temperature of the object comprising the step of determining the temperature within a range of temperatures.

54. The method of claim 48, said object being servingware.

55. The temperature sensor of claim 54, said sensor oriented to measure the temperature of food placed on said servingware,.

63. The system of claim 49, said object being servingware.

64. The system of claim 63, said sensor oriented to measure the temperature of food placed on said servingware.

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

a temperature sensor configured to be adhesively affixed to the object and operable for sensing a temperature of the object, the temperature sensor comprising at least one sensor element and an adhesive for securing the sensor element to the object;

a heating unit for heating the object;

a reader/detector operable to generate an alternating magnetic field to detect a re-magnetization response of the sensor element, and generate an output signal correlated with the detected re-magnetization response; and

a controller coupled with the reader/detector and the heating unit and operable to receive the output signal and to control operation of the heating unit in response to the output signal.

57. The system of claim 56, the heating unit being selected from the group consisting of an induction heater, a heat lamp assembly, a steam table, and a microwave oven.

58. The system of claim 56, including a substrate, said sensor element supported on said substrate, said substrate being formed of a material selected from the group consisting of:

a polymer film, polyethylene terephthalate (PET), polyethylene, polypropylene, cellulose, paper, and pulp-type materials.

59. he system of claim 58, wherein the substrate is generally circular with a diameter of approximately 10-30 mm and a thickness of approximately 0.0025-0.01 inches.

60. The system of claim 58, wherein the substrate is formed of a material that dissolves when exposed to water.

61. The system of claim 56, wherein the adhesive is an ultraviolet light curable adhesive.

62. The system of claim 56, further including a removable release layer positioned over the adhesive which may be removed to expose one face of the adhesive for securing the temperature sensor to the object.

65. The combination comprising:

a servingware piece; and

a temperature sensor affixed to said servingware piece and comprising

at least one sensor element; and

an adhesive securing the sensor element to the servingware so that the sensor element may sense a parameter relating to the temperature of the servingware.

66. The combination of claim 65, wherein the parameter is selected from the group consisting of a temperature of the servingware, a desired temperature of the servingware, a temperature range of the servingware, a desired temperature range of the servingware, a minimum temperature of the servingware, a maximum temperature of the servingware, a heating property of the servingware, and the temperature of food on the servingware.

67. The combination of claim 65, the sensor element comprising a magnetically susceptible sensor element having a re-magnetization response under the influence of an applied alternating magnetic field, the re-magnetization response defined by at least one short, detectible pulse of magnetic field perturbation of defined duration and being different below and above at least one set point temperature below about 400°

C.

68. The combination of claim 65, there being a plurality of the sensor elements, with at least certain of the sensor elements having a different set point temperature than other of the sensor elements.

69. The combination of claim 65, the set point temperature being a Curie temperature of the sensor element.