Test methodology to determine power ouput of a thermistor under a defined thermal load

Patent metadata

Field	Value
Publication number	US-12326372-B2
Application number	US-202117456234-A
Country	US
Kind code	B2
Filing date	Nov 23, 2021
Priority date	Feb 25, 2021
Publication date	Jun 10, 2025
Grant date	Jun 10, 2025

Abstract

A methodology includes circulating a temperature-controlled and flow-rate-controlled medium through a container at a controlled flow rate and submerging a thermistor with the medium. With the thermistor submerged, a power output of the thermistor is determined and compared to a power criterion, after which classification of the thermistor occurs based on a comparison of the power output to the power criterion. The methodology can include submerging a reference thermistor within the medium and determining a reference power output of the reference thermistor with the reference thermistor submerged within the medium, the power criterion determined based on the reference power output.

First claim

The invention claimed is:

1. A method comprising:
circulating a medium through a container;
controlling a temperature of the medium delivered to the container;
controlling a flow rate of the medium delivered to the container;
submerging a thermistor within the medium; and
determining a power output of the thermistor while the thermistor is submerged within the medium and the medium circulates through the container; and
classifying the thermistor based on a comparison between the power output of the thermistor and a power criterion.

2. The method of claim 1 , wherein the thermistor is a positive temperature coefficient resistor.

3. The method of claim 1 , wherein determining the power output of the thermistor includes attaching a two-wire connection to the thermistor.

4. The method of claim 1 , wherein the temperature of the medium is controlled to a temperature setpoint.

5. The method of claim 4 , wherein the flow rate of the medium is controlled to a flow rate setpoint.

6. The method of claim 1 , wherein the thermistor is one of a plurality of thermistors; and wherein the method further comprises:
submerging each thermistor from the plurality of thermistors within the medium;
determining the power output of each thermistor from the plurality of thermistors while each thermistor is submerged within the medium and the medium circulates through the container; and
selecting a reference thermistor from the plurality of thermistors based on a target power output within a distribution of power outputs of the plurality of thermistors; and
determining the power criterion based on the power output of the reference thermistor.

7. The method of claim 6 , wherein the target power output is indicative of a subset of power outputs within the distribution of power outputs that is less than at least 90% of power outputs within the distribution of power outputs.

8. The method of claim 1 , wherein determining the power output of the thermistor includes applying a constant voltage to the thermistor.

9. The method of claim 8 , wherein determining the power output of the thermistor includes measuring an electrical current at the thermistor while applying the constant voltage to the thermistor.

10. The method of claim 9 , wherein determining the power output of the thermistor includes attaching a four-wire connection to the thermistor in which a first pair of leads measures the constant voltage at the thermistor and a second pair of leads measures the electrical current passing at the thermistor contemporaneously with measuring the voltage at the thermistor via the first pair of leads.

11. A method comprising:
circulating a medium through a container;
controlling a temperature of the medium delivered to the container;
controlling a flow rate of the medium delivered to the container;
submerging a plurality of thermistors within the medium; and
determining a power output of each thermistor of the plurality of thermistors while the plurality of thermistors is submerged within the medium and the medium circulates through the container; and
classifying each thermistor of the plurality of thermistors based on a comparison between the power output and a power criterion.

12. The method of claim 11 , wherein each four-wire connection of the plurality of four-wire connections attaches to one of the plurality of thermistors by inserting the one thermistor into the receiving portion of the fixture.

13. The method of claim 11 , further comprising:
submerging a reference thermistor within the medium;
determining a reference power output of the reference thermistor while the reference thermistor is submerged within the medium and the medium circulates through the container; and
determining the power criterion based on the reference power of the reference thermistor.

14. The method of claim 11 , further comprising:
installing each thermistor of the plurality of thermistors within a receiving portion of a fixture prior to submerging the plurality of thermistors within the medium.

15. The method of claim 14 , further comprising: attaching each four-wire connection of a plurality of four-wire connections to one of the plurality of thermistors, and wherein each four-wire connection of the plurality of four-wire connections includes a first pair of leads measuring a voltage at one of the plurality of thermistors and a second pair of leads measuring an electrical current passing at the one of the plurality of thermistors.

16. A method comprising:
circulating a medium through a container;
controlling a temperature of the medium delivered to the container;
controlling a flow rate of the medium delivered to the container;
submerging a first thermistor within the medium;
determining a reference power output of the first thermistor while the first thermistor is submerged within the medium and the medium circulates through the container;
determining a power criterion based on the reference power output of the first thermistor;
submerging a second thermistor within the medium that is different from the first thermistor;
determining a second power output of the second thermistor while the second thermistor is submerged within the medium and the medium circulates through the container; and
classifying the second thermistor based on a comparison between the second power output and the power criterion.

17. The method of claim 16 ,
wherein the temperature of the medium is controlled to a temperature setpoint; and
wherein the flow rate of the medium is controlled to a flow rate setpoint.

18. The method of claim 16 ,
wherein the first thermistor is one of a plurality of first thermistors; and
wherein the method further comprises:
submerging each first thermistor from the plurality of first thermistors within the medium;
determining a third power output of each first thermistor from the plurality of first thermistors while each first thermistor is submerged within the medium and the medium circulates through the container; and
selecting the first thermistor from the plurality of first thermistors based on a target power output within a distribution of third power outputs of the first thermistors.

19. The method of claim 18 , wherein the target power output is indicative of a subset of third power outputs within the distribution of third power outputs that is less than at least 90% of third power outputs within the distribution of third power outputs.

Assignees

• Rosemount Aerospace Inc

Inventors

• Hanson Daniel
• Schwartz Richard Alan
• Jenkins Alexandra C
• Anderson Luke

Classifications

• G01K7/22

  the element being a non-linear resistance, e.g. thermistor (G01K7/26 takes precedence) · CPC title

• G01K15/007 Primary

  Testing · CPC title

• G01K15/00 Primary

  Testing or calibrating of thermometers · CPC title