Electrical resistance of platinum at a pressure of up to 1 GPa

The Calibration of Data Loggers for the Characterization of Sterilization Autoclaves

“…The data loggers (1,2) are inserted in the cylindrical measurement chamber (3) which in turn is completely immersed in the temperature bath (4). The chamber is connected to a digital pressure gauge with a remote transducer (6), via a heat exchanger (5), constructed in 6.35 mm diameter copper seamless tube that is maintained at 23 • C. The bath temperature is measured in the bath fluid using two SPRTs placed on opposite sides of the chamber and at different depths of immersion (7,8). These are measured using a precision AC resistance bridge (9) and standard resistors maintained in an oil bath.…”

“…It is common practice to calibrate these devices by comparison at complete immersion in liquid baths, at atmospheric pressure, using standard platinum resistance thermometers (SPRTs) as reference standards. However, the electronics and temperature sensors, usually industrial platinum resistance thermometers (IPRTs) [4] exhibit a pressure dependence [5][6][7] that must be accounted for if the conditions of use differ from those of calibration.…”

“…Schematic of the calibration system: (1, 2) data loggers, (3) measurement chamber, (4) temperature bath, (5) heat exchanger at 23 • C, (6) pressure transducer,(7,8) standard platinum resistance thermometers, (9) resistance bridge, (10) heat exchangers in bath, (11, 13) heat exchanger at 23 • C, (12) external volume at 23 • C, (14) pressure controller, (15) regulated air supply, (16) vacuum pump, and (17) vacuum gauge…”