Filled Systems

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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