THERMOMETER CALIBRATION BY IMMERSION IN NON-ELECTRICALLY CONDUCTIVE LIQUID
A method for calibrating a thermometer is disclosed. The thermometer comprises a primary temperature sensor for determining the temperature of a target. The thermometer also comprises a reference temperature sensor positioned proximate to the primary temperature sensor and being responsive to an extraneous temperature affecting the primary temperature sensor. One calibration method calibrates the reference temperature sensor. This calibration can utilize a non-electrically conductive liquid bath for temperature control. Another calibration method calibrates the reference temperature sensor and the primary temperature sensor.
1 . A method of calibrating an electronic temperature sensor of an electronic temperature device comprising:
forming a bath of non-electrically conductive liquid;
maintaining the bath at a predetermined temperature;
placing the electronic temperature sensor in contact with the bath;
reading an output characteristic of the temperature sensor in the bath; and
using the output characteristic to calibrate the temperature sensor.
2 . A method as set forth in claim 1 wherein placing the temperature sensor comprises positioning the temperature sensor within the non-electrically conductive liquid free of liquid barriers between the temperature sensor and the non-electrically conductive liquid.
3 . A method as set forth in claim 2 wherein during the step of positioning the temperature sensor within the non-electrically conductive liquid, the non-electrically conductive liquid makes contact with an electrically conducting component of the temperature sensor.
4 . A method as set forth in claim 1 further comprising repeating the forming, maintaining, and placing, for a second predetermined temperature different than the predetermined temperature;
reading a second output characteristic of the temperature sensor in the bath maintained at the second predetermined temperature; and
using the output characteristics to calibrate the temperature sensor.
5 . A method as set forth in claim 1 wherein said forming a bath of non-electrically conductive liquid comprises forming a bath of low molecular weight perfluoropolyether (PFPE) liquid.
6 . A method as set forth in claim 1 wherein said maintaining the bath at a predetermined temperature comprises maintaining the predetermined temperature of the bath to within a range from about ±0.005 degrees C. (±0.009 degrees F.) to about ±0.01 degrees C. (±0.018 degrees F.).
7 . A method as set forth in claim 1 wherein said placing the electronic temperature sensor in contact with the bath comprises placing the electronic temperature sensor in contact with the bath for a period of between about 15 minutes and about 30 minutes before reading said output characteristic.
8 . A method as set forth in claim 1 wherein said reading an electrical output characteristic comprises monitoring the output characteristic until it changes less than about 0.1 percent in at least about one minute and then performing said reading operation.
9 . A calibration apparatus for calibrating electronic devices, said calibration apparatus comprising:
a container adapted for receiving at least a portion of an electronic device;
a non-electrically conductive liquid received within said container, whereby the container and the non-electrically conductive liquid cooperate to form a non-electrically conductive bath adapted for immersion of the electronic device in the non-electrically conductive liquid for maintaining the electronic device at the same temperature as the non-electrically conductive liquid; and
a communication link adapted for establishing communication with the electronic device when the electronic device is immersed in the non-electrically conductive liquid.
10 . A calibration apparatus as set forth in claim 9 wherein said non-electrically conductive liquid is a low molecular weight perfluoropolyether (PFPE) liquid.
11 . A calibration apparatus as set forth in claim 10 wherein said non-electrically conductive liquid is an oxidized, polymerized, 1,1,2,3,3,3-hexafluoro propene.
12 . A calibration apparatus as set forth in claim 9 wherein said container is adapted for receiving two or more electronic devices.
13 . A calibration apparatus as set forth in claim 9 further comprising a fixture adapted for loading and unloading the electronic device to and from the non-electrically conductive liquid.
14 . A calibration apparatus as set forth in claim 9 wherein said communication link comprises at least one of a wire lead and a wireless communication link.