A New Mercury Gas-Controlled Heat Pipe for Temperature Amplifier and as Calibration Facility

At the Italian National Research Institute of Metrology the activities and studies on the Gas Controlled Heat Pipes are constantly increasing in terms of involved personnel, instrumentations and devices available. In last two years, among the other activities, a totally new Gas-Controlled Heat Pipe operating with mercury as working fluid has been designed, manufactured and completely characterised. This Heat Pipe is made in stainless steel and provided with three thermometers wells. A dedicated furnace has been constructed too and specific software algorithms have been implemented for the temperature and pressure control. This device will be used as low temperature reference for the new “Temperature Amplifier” and, at the same time, as calibration facility for thermometers calibrations by comparison in the field between 220 °C and 450 °C. All details regarding this Heat Pipe, including assembly, filling and testing procedures, and the complete characterisation campaign are here summarised. Results in terms of temperature stability, uniformity, time response are reported, and demonstrate the capabilities of this Gas Controlled Heat Pipe to be a useful device for researches and applications in contact thermometry. A further Gas Controlled Heat Pipe operating with mercury has been manufactured, provided with six thermometer wells and will be characterised for the contact thermometry calibration laboratory on INRiM and for other calibration groups; this device is presented too.