Performance Characteristics of Custom Thermocouples for Specialized Applications

Abstract

This work reports the performance characteristics of custom thermocouples developed for use in elevated temperatures such as metal casting operations. The scope of this research is limited to thermocouples designed using pyrolytic graphite (PG) as the primary thermoelement in connection with aluminum, copper, steel, and tungsten. The Seebeck coefficients of the sensors were determined from experimental data after heating to ~500 °C. Cooling from ~500 °C to room temperature enabled us to compare the characteristic behaviors of the sensors from the obtained near-linear responses in the voltage-temperature plots. Tungsten being a refractory metal produced the highest sensitivity of the sensors. The sensitivity of the PG-tungsten thermocouple upon heating measured up to 26 μV/°C and a slightly lower value of 24.2 μV/°C was obtained upon cooling. Conversely, the PG-steel thermocouple rather produced the lowest Seebeck coefficients of 13.8 μV/°C during heating and 14.0 μV/°C for the cooling experiments though steel has a high melting temperature than most of the other thermoelements.

Structural Design of Dual-Type Thin-Film Thermopiles and Their Heat Flow Sensitivity Performance

“…When the heat flow is applied vertically to the sensor, due to the difference in thermal conductivity between the SiO 2 and Al 2 O 3 thermal resistive layers, the Al 2 O 3 thermal resistive layer with high thermal conductivity transfers the excess heat from the cold end to the Al 2 O 3 ceramic substrate to form the cold end, while the SiO 2 thermal resistive layer with low thermal conductivity restricts the heat transfer from the hot end to the substrate to form the hot end, which creates a temperature gradient between the hot end and the cold end. The underlying temperature distribution of the bottom layer is also different, so we detect the temperature distribution of the bottom layer by adding a thermopile layer [ 26 , 27 , 28 ]. Therefore, it is possible to infer the heat flow in the top layer or the power of the laser by observing the output voltage.…”

“…tween the hot end and the cold end. The underlying temperature distribution of the bottom layer is also different, so we detect the temperature distribution of the bottom layer by adding a thermopile layer [26][27][28]. Therefore, it is possible to infer the heat flow in the top layer or the power of the laser by observing the output voltage.…”

Examination of Morphological and Chemical Properties of Ni-BZY Anodes and their Influence upon Methane Reactivity and Electrochemical Performance of Protonic-Ceramic Fuel Cells

“…The approximate steam content in the anode gas supply was verified by condensing and weighing the liquid. K-type thermocouples were used for temperature monitoring within the reactor and steamer lines due to their sensitivity and ability to function in high temperature conditions (17). A schematic of the setup for testing the fuel cells is depicted in Figure 1.…”