Method and apparatus for measuring heat flow

• US 20020173730A1
• Filed: 05/15/2001
• Published: 11/21/2002
• Est. Priority Date: 05/15/2001
• Status: Active Grant

• Current Assignee: Lifechek LLC
• Original Assignee: Lifechek LLC
• Inventors: Szuminsky, Neil J., Pottgen, Paul A.
• Granted Patent: US 6,533,731 B2
• Time in Patent Office: Days
• US Class Current: 600/549
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 2562/0271 Thermal or temperature sensors
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/441 Skin evaluation, e.g. for skin disorder diagnosis
• CPC Class Codes: A61B 5/4866 Evaluating metabolism A61B5/083 takes precedence
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: G01K 17/00 Measuring quantity of heat measuring temperature by calorimetry G01K3/00 - G01K11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion G01N

Abstract

A method and apparatus for determining caloric expenditure of a subject. The apparatus includes a heat flow sensor having an overlay and/or conductive layer for measuring the evaporative heat loss, in addition to substantially total heat loss, for the subject. The sensor also includes a structure to enhance the migration of perspiration from edges or a bottom of the sensor onto an active region of the sensor. One sensor includes electrodes to effectuate electroendosmosis such that positively biased electrodes are formed at an edge or bottom of the sensor and a negatively biased electrode is formed at a center or top of the sensor. Through electroendosmosis the perspiration is migrated from the positively biased electrodes at the edge or bottom of the sensor to the negatively biased electrode in the center or top of the sensor. Another sensor places thermocouples at edges of a sensing portion to reduce a distance that the perspiration has to migrate. Enhancing the migration of perspiration enhances the measurement of evaporative heat loss. The output of the sensor can also be provided to a device such as a personal computer, a personal digital assistant (PDA), etc.

Claims

1. An apparatus for determining caloric expenditure by measuring total heat flow from the skin surface of a wearer of the apparatus comprising:

a) a heat flow sensor configured to measure heat flow, said heat flow sensor including;

a1) an interlayer; and

a2) first and second thermocouple elements formed on a first surface near an edge of said interlayer.

2. An apparatus according to claim 1, further comprising:

(b) an overlay material, at least a portion of which contacts said wearer'"'"'s skin surface and another portion of which covers said heat flow sensor, said overlay material being capable of imbibing a fluid and allowing said fluid to migrate from said skin surface to the portion of said overlay material contacting said heat flow sensor such that said imbibed fluid can evaporate from said portion of said overlay material covering said heat flow sensor.

3. An apparatus according to claim 2, wherein said skin surface and said overlay material have essentially the same evaporation rate.

4. An apparatus according to claim 2, wherein said overlay material is selected from the group consisting of leather, synthetic membranes, and tight-weave fabrics.

5. An apparatus according to claim 2, further comprising:

(b) a thermally conductive material located between said heat flow sensor and said overlay material to create a substantially uniform heat flow across said surface of said heat flow sensor.

6. An apparatus according to claim 5, wherein said thermally conductive material is selected from the group consisting of metal foil, vacuum deposited metal film, and thermally conductive plastics.

7. An apparatus according to claim 6, wherein both said overlay material and said skin have essentially the same evaporation rate.

8. An apparatus according to claim 1, further comprising:

(b) an overlay material, at least a portion of which contacts said weaver'"'"'s skin surface and another portion of which covers said heat flow sensor, said overlay material formed of a membrane including first Nylon™

fibers and second CoolMax™

fibers interwoven with said first Nylon™

fibers.

9. An apparatus according to claim 8, further comprising:

(c) a thermally conductive material located between said heat flow sensor and said overlay material to create a substantially uniform heat flow across said surface of said heat flow sensor.

10. An apparatus according to claim 9, wherein said thermally conductive material is selected from the group consisting of metal foil, vacuum deposited metal film, and thermally conductive plastics.

11. An apparatus according to claim 1, further comprising:

b) an output configured to provide data from said heat flow sensor to a computing device.

13. An apparatus according to claim 12, further comprising:

(b) overlay means for imbibing a fluid and allowing said fluid to migrate from said skin surface to the portion of said overlay material contacting said heat flow sensor such that said imbibed fluid can evaporate from said portion of said overlay material covering said heat flow sensor.

14. An apparatus according to claim 12, further comprising:

(b) thermally conductive means for creating a substantially uniform heat flow across said surface of said heat flow sensor means.

15. An apparatus according to claim 13, further comprising:

(c) thermally conductive means for creating a substantially uniform heat flow across said surface of said heat flow sensor means.

17. An apparatus according to claim 16, wherein said at least one positively biased electrode includes two positively biased electrodes, and said at least one negatively biased electrode is positioned between the two positively biased electrodes.

18. An apparatus according to claim 16, wherein said at least one positively biased electrode is positioned near the skin surface of the wearer and said at least one negatively biased electrode is positioned above said at least one positively biased electrode in a depth direction of said heat flow sensor.

19. An apparatus according to claim 16, further comprising:

(b) an overlay material, at least a portion of which contacts said wearer'"'"'s skin surface and another portion of which covers said heat flow sensor, said overlay material being capable of imbibing a fluid and allowing said fluid to migrate from said skin surface to the portion of said overlay material contacting said heat flow sensor such that said imbibed fluid can evaporate from said portion of said overlay material covering said heat flow sensor.

20. An apparatus according to claim 19, wherein said skin surface and said overlay material have essentially the same evaporation rate.

21. An apparatus according to claim 19, wherein said overlay material is selected from the group consisting of leather, synthetic membranes, and tight-weave fabrics.

22. An apparatus according to claim 19, further comprising:

(b) a thermally conductive material located between said heat flow sensor and said overlay material to create a substantially uniform heat flow across said surface of said heat flow sensor.

23. An apparatus according to claim 22, wherein said thermally conductive material is selected from the group consisting of metal foil, vacuum deposited metal film, and thermally conductive plastics.

24. An apparatus according to claim 23, wherein both said overlay material and said skin have essentially the same evaporation rate.

25. An apparatus according to claim 16, further comprising:

(b) an overlay material, at least a portion of which contacts said weaver'"'"'s skin surface and another portion of which covers said heat flow sensor, said overlay material formed of a membrane including first Nylon™

fibers and second CoolMax™

fibers interwoven with said first Nylon™

fibers.

26. An apparatus according to claim 25, further comprising:

(c) a thermally conductive material located between said heat flow sensor and said overlay material to create a substantially uniform heat flow across said surface of said heat flow sensor.

27. An apparatus according to claim 26, wherein said thermally conductive material is selected from the group consisting of metal foil, vacuum deposited metal film, and thermally conductive plastics.

28. An apparatus according to claim 16, further comprising:

b) an output configured to provide data from said heat flow sensor to a computing device.

30. An apparatus according to claim 29, further comprising:

(b) overlay means for imbibing a fluid and allowing said fluid to migrate from said skin surface to the portion of said overlay material contacting said heat flow sensor such that said imbibed fluid can evaporate from said portion of said overlay material covering said heat flow sensor.

31. An apparatus according to claim 29, further comprising:

(b) thermally conductive means for creating a substantially uniform heat flow across said surface of said heat flow sensor means.

32. An apparatus according to claim 30, further comprising:

(c) thermally conductive means for creating a substantially uniform heat flow across said surface of said heat flow sensor means.

12. An apparatus for determining caloric expenditure by measuring total heat flow from the skin surface of a wearer of the apparatus comprising:

a) heat flow sensor means for measuring heat flow, said heat flow sensor means including;

a1) thermocouple means for forming thermocouple elements at an edge of said heat flow sensor means.

16. An apparatus for determining caloric expenditure by measuring total heat flow from the skin surface of a wearer of the apparatus comprising:

a) a heat flow sensor configured to measure heat flow, said heat flow sensor including;

a1) at least one positively biased electrode; and

a2) at least one negatively biased electrode.

29. An apparatus for determining caloric expenditure by measuring total heat flow from the skin surface of a wearer of the apparatus comprising:

a) heat flow sensor means for measuring heat flow, said heat flow sensor means including;

a1) means for migrating perspiration from an edge of said heat flow sensor means to a most active region of said heat flow sensor means.