See the below file for instructions to assemble a temperature probe to tube fittings and adapters to monitor the temperature of gas flowing through a tube. This is commonly used to monitor the outlet gas temperature from a rotameter (variable area flow meter) to make a square root density correction.
Note that the pressure fitting should be closer to the outlet of the rotameter than the temperature fitting because there might be some pressure drop over the temperature probe.
The temperature monitoring device in the image is a Fluke Calibration 1524 with a 5665-P thermistor probe.
1523, 1524 Reference Thermometers
5665 Temperature Probe
If tying to determine which type of sensor/probe to use on a 1523/1524 we recommend thermistors as best for fast response, shallow immersion depths, and best accuracy. They are also shorter and thinner probe diameter which might help integrating them into the flow path. The 5610-9 thermistor is a recommended choice.
Contact Fluke Calibration Flow Technical Support at the below link or by calling +1-877-355-3225