GBTs

GBTs, or Gas Bulb Thermometers, are a type of temperature-measuring device that utilizes the principle of thermal expansion of a gas. Typically, a sealed glass bulb containing a gas such as nitrogen or air is connected to a capillary tube. As the temperature of the bulb changes, the gas inside expands or contracts. This change in volume causes the gas to move up or down the capillary tube. A scale, calibrated to known temperature points, is placed alongside the capillary tube, allowing for a direct reading of the temperature. The accuracy of a GBT depends on factors like the amount of gas, the volume of the bulb, and the quality of the calibration. They are often used in applications where a relatively simple and robust temperature measurement is required, such as in laboratory settings, industrial processes, and some meteorological instruments. GBTs are generally not as precise as some other thermometer types but offer advantages in terms of durability and cost-effectiveness for certain applications. Their operation is based on the ideal gas law, where pressure, volume, and temperature are directly related.