Triple Point of Mercury Maintenance Apparatus

Within the ITS-90, the temperature values of both the water triple point and the mercury triple point are realized using a precision liquid (water or alcohol) bath. These thermostats feature a temperature control stability of ±0.002°C and can achieve low temperatures down to -42 ℃ . The bath is equipped with a color touch screen, input ports for standard platinum resistance thermometers (SPRTs), and a curve display function for easy observation of temperature plateau realization. It has a depth of 520 mm, weighs approximately 40 kg, and features a working chamber diameter of 138 mm. Cooling is provided by a single-stage refrigeration system, which incorporates multiple protection features along with rapid cooling and low-noise operation modes.