Calibrated assembly for IR thermometer apparatus

• US 8,186,876 B2
• Filed: 04/20/2009
• Issued: 05/29/2012
• Est. Priority Date: 04/20/2009
• Status: Active Grant

• Current Assignee: Welch Allyn Incorporated
• Original Assignee: Welch Allyn Incorporated
• Inventors: Mullin, Matthew D., Anson, Michael J., Lane, John A., Quinn, David E., Smith, Henry J. III, Stone, Ray D.
• Primary Examiner(s): VERBITSKY, GAIL KAPLAN
• Application Number:
  US12/426,556
• Publication Number:
  US 20100265986A1
• Time in Patent Office: 1,135 Days
• Field of Search: 374/1, 374/120, 374/121, 374/129, 374/132, 374/163, 374/164, 374170-172, 374/208, 374/2, 374/158, 374/209, 600/549, 600/474, 600/184, 702130-136, 702/99, 250/338.1
• US Class Current: 374/121
• CPC Class Codes: G01J 5/0003 for sensing the radiant heat transfer of samples, e.g. emittance meter
• CPC Class Codes: G01J 5/0011 Ear thermometers G01J5/021 and G01J5/049 take precedence
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/021 Probe covers for thermometers, e.g. tympanic thermometers; Containers for probe covers; Disposable probes
• CPC Class Codes: G01J 5/025 Interfacing a pyrometer to an external device or network; User interface
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/049 Casings for tympanic thermometers
• CPC Class Codes: G01J 5/061 by controlling the temperature of the apparatus or parts thereof, e.g. using cooling means or thermostats

Abstract

A tip assembly for an IR thermometer apparatus includes a heat sink having a heat sink cavity and a tip section and a fluid path and at least one hydraulic port. The tip assembly also includes an IR sensor mechanically seated in the tip section and thermally coupled to the heat sink. The tip assembly also includes an electrical connector configured to provide an electrical connection to the tip assembly. A fluid having a fluid temperature is introduced into the fluid path via the hydraulic port. The fluid causes the heat sink and the IR sensor to substantially reach one or more pre-determined temperatures by thermal conduction during calibration of the tip assembly. Another tip assembly having an internal heat source is described. Another tip assembly having an internal heat pump is described. A method to calibrate a tip assembly is also described.

Claims

1. An IR thermometer apparatus having a tip assembly, said tip assembly comprising:

a tip section defined by a heat sink having a cavity, a fluid path defined within said tip section, and at least one hydraulic port;

an IR sensor disposed within said tip section and thermally coupled to said heat sink;

a shroud overlaying at least said tip section;

an electrical connector configured to provide electrical coupling to an electronic circuit disposed within said tip assembly, wherein a fluid having a fluid temperature is introduced into said fluid path via said at least one hydraulic port, and wherein said fluid causes said heat sink and said IR sensor to substantially reach one or more pre-determined temperatures by thermal conduction during calibration of said tip assembly and wherein said fluid is substantially removed after calibration;

a cover detection mechanism to detect attachment of a calibration cover, said calibration cover comprising a reflective surface over a window of said IR sensor; and

a heating element electrically configured to be heated to a predetermined temperature on detection of placement of said calibration cover on said tip assembly, and wherein the reflective surface over the window of the IR sensor reflects IR radiation from said heating element, said received IR radiation being used as a calibration check of said tip assembly.

2. The tip assembly of claim 1, wherein said fluid path comprises a hydraulic channel extending through heat sink.

3. The tip assembly of claim 1, wherein said fluid path comprises an air gap.

4. The tip assembly of claim 3, wherein said air gap is disposed between said heat sink and said shroud.

5. The tip assembly of claim 1, wherein said at least one hydraulic port includes both an inflow connection and an outflow connection configured to allow a fluid flow through said fluid path.

6. The tip assembly of claim 1, wherein said tip section includes two hydraulic ports, wherein a first hydraulic port is configured for fluid inflow and a second hydraulic port is configured for fluid outflow to create a fluid flow through said fluid path and said first hydraulic port and said second hydraulic port are interchangeable for fluid inflow or outflow.

7. The tip assembly of claim 1, wherein said heat sink is thermally isolated from said shroud by at least one air gap.

8. The tip assembly of claim 1, further comprising a memory communicatively coupled to said electrical connector.

9. The tip assembly of claim 8, wherein said memory comprises an EEPROM.

10. The tip assembly of claim 1, wherein said IR thermometer apparatus is configured such that at least once before a temperature measurement is made by said IR thermometer apparatus said calibration coefficients are read from said memory of said tip assembly via said electrical connector by an algorithm running on a microcomputer circuit disposed within said IR thermometer apparatus.

11. The tip assembly of claim 1, further comprising an electronics circuit electrically coupled to said IR sensor, said electronics circuit including an amplifier to amplify an IR sensor signal from said IR sensor, an analog to digital converter (ADC) electrically coupled to said amplifier and configured to digitize an amplified IR sensor signal and to provide an output via said electrical connector.

12. The tip assembly of claim 11, wherein said amplifier and said ADC are both disposed on a common integrated circuit.

13. The tip assembly of claim 11, further including microcomputer resident within said tip assembly wherein said tip assembly is configured such that at least once, said calibration coefficients are read from said memory of said tip assembly by an algorithm running on said tip assembly microcomputer circuit during a measurement and said tip assembly outputs a digital value corrected by said calibration coefficients via said electrical connector.

14. The tip assembly of claim 11, wherein said electronic circuit includes a voltage reference configured to be electrically coupled to said ADC via an electronic switch to calibrate said ADC in response to a control signal sent to said tip assembly via said electrical connector.

15. The tip assembly of claim 14, wherein said microcomputer and said ADC are both disposed on a common integrated circuit.

16. The tip assembly of claim 1, wherein said IR sensor comprises a thermopile.

17. The tip assembly of claim 1, further including an exteriorly disposed threaded portion on said heat sink enabling attachment to attach to said IR thermometer apparatus.

18. The tip assembly of claim 1, further including a slide and latch mechanism enabling attachment of said tip assembly to said IR thermometer apparatus.

19. The tip assembly of claim 1, wherein said tip assembly includes at least one flange enabling mechanical attachment is to said IR thermometer apparatus.

20. The tip assembly of claim 1, wherein said tip assembly comprises a liquid tight housing.

21. The tip assembly of claim 1, wherein if said calibration check is out of pre-determined limits, said calibration coefficients are updated and stored in a memory disposed within said tip assembly.

22. The tip assembly of claim 1, wherein said heating element comprises a thermistor.

23. The tip assembly of claim 22, wherein said thermistor is configured to be used for measuring a heat sink temperature of said IR sensor during a normal operation of said tip assembly, and as a heating element used for calibration during a calibration check of said tip assembly.

24. The tip assembly of claim 1, wherein said cover detection mechanism to detect attachment of said calibration cover comprises at least one of electro-mechanical switch, electro-optical cover detection, and capacitive cover detection.

25. The tip assembly of claim 1, wherein said calibration coefficients are calculated by an external test fixture and written into said memory of said tip assembly during a calibration process.

26. The tip assembly of claim 1, further including an embedded microcomputer.

27. The tip assembly of claim 26, wherein said calibration coefficients are calculated by said embedded microcomputer and written into a memory during a calibration process.

28. An IR thermometer comprising:

a calibrated tip assembly according to claim 1;

a microcomputer circuit communicatively coupled to said calibrated tip assembly via said electrical connector, said microcomputer circuit running an algorithm configured to receive a digital signal representing a measured temperature and to communicate with said memory to read one or more calibration coefficients and to output a measured temperature; and

an IR thermometer housing, said calibrated tip assembly being releasably attached to said IR thermometer housing, and wherein

said IR thermometer is in a calibrated state following attachment of said calibrated tip assembly to said thermometer housing.

29. The IR thermometer of claim 28, wherein said microcomputer circuit is configured to output said measured temperature via at least one of a human readable display, a wired data connection, and a wireless data connection.

30. The IR thermometer apparatus of claim 1, further comprising:

a heat pump thermally coupled to said heat sink;

wherein a temperature of said

heat sink and said IR sensor is set to one or more pre-determined temperatures by heating or cooling as caused by said heat pump during calibration of said tip assembly.

31. A tip assembly for an IR thermometer apparatus comprising:

a tip section;

a heat sink disposed in said tip section and having a heat sink cavity;

a heating element thermally coupled to said heat sink;

an IR sensor mechanically seated in said tip section of said tip assembly and thermally coupled to said heat sink;

a shroud mechanically covering at least a portion of said tip section;

a cover detection mechanism to detect attachment of a calibration cover, said calibration cover comprising a reflective surface over a window of said IR sensor; and

an electrical connector configured to provide electrical coupling to an

electronic circuit disposed within said tip assembly, wherein a temperature of said heat sink and said IR sensor is set to one or more pre-determined temperatures by heating caused by said heating element during calibration of said tip assembly, said heating element being electrically configured to be heated to a pre-determined temperature upon detection of placement of said calibration cover on said tip assembly, and wherein said reflective surface reflects IR radiation from said heating element and said received IR radiation is used as a calibration check of said tip assembly.

32. A method to calibrate a tip assembly, said method comprising the steps of:

providing a tip assembly to be calibrated, said tip assembly including an IR sensor, a heat sink thermally coupled to said IR sensor, and at least one fluid path disposed within said tip assembly;

flowing a fluid at a pre-determined temperature though said at least one fluid path while said IR sensor is viewing a calibrated temperature target at a pre-determined target temperature to obtain a calibration data point;

repeating said flowing step one or more times;

calculating a set of calibration coefficients from two or more data points to calibrate said tip assembly; and

storing said set of calibration coefficients on a recordable media wherein said tip assembly is liquid-tight and wherein during said flowing step(s), said tip assembly is submerged within a liquid bath.

33. The method of claim 32, wherein said providing step comprises providing a tip assembly wherein said at least one fluid path disposed within said tip assembly comprises a fluid channel.

34. The method of claim 32, wherein said providing step comprises providing a tip assembly wherein said at least one fluid path disposed within said tip assembly comprises an air gap channel disposed between said heat sink and a tip shroud.

35. The method of claim 32, wherein said step of storing said calibration coefficients comprises storing said calibration coefficients on a memory.

36. A method to releasably attach a tip assembly to an apparatus, said method comprising the steps of:

providing a tip assembly to be releasably attached to an apparatus, said tip assembly including an IR sensor, a heat sink thermally coupled to said IR sensor, and at least one fluid path disposed within said tip assembly;

attaching said tip assembly to said apparatus; and

releasing said tip assembly from said apparatus for a selected one of cleaning said tip assembly, replacing said tip assembly, and calibrating said tip assembly, wherein said calibrating step further comprises the step of attaching a calibration cover onto a tip section of said tip assembly, detecting the attachment of said calibration cover, said calibration cover including a reflective surface over a window of said IR sensor, and heating a heating element to a predetermined temperature upon detection of attaching of said calibration cover to said tip assembly such that the reflective surface of said calibration cover reflects IR radiation from said heating element, the IR radiation received being used as a calibration check of said tip assembly.

37. The method of claim 36, wherein said attaching step further comprises attaching a disposable cover to a tip section of said tip assembly.