Filled System, or just filled thermometers are those that work on pressure or volume change of a gas or changes in vapor pressure of a liquid.
The gas or gas and liquid are contained usually in a sealed metal tubing and bulb system.
If you have an electric or gas oven in the USA, chances are the temperature sensor in the oven looks like a metal tube with a fat bump on the end. That’s a filled system thermometer.
The gas type were used in many industrial applications and for establishing portions of the thermodynamic temperature scale. They can be very simple, non-powered devices with great reliability and repeatability.
The vapor pressure types have a bulb, the sensing portion, filled with a volitile liquid, instead of a gas.
Since they are more sensitive to temperature changes than a gas type, they can be physically smaller, however their relative temperature measurement span is quite a bit smaller.
- Filled system Thermometer, Types, Construction
- Recommended Use Limits and Tolerances
- How filled system Thermometers Work, Lose Calibration and Fail
- Filled System Thermometer Vendors
- Miscellaneous Information
- Thermometer Applications
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