Linear Thermocouple Research Articles

The Gas Fire Temperature Measurement for Detection of an Object’s Presence on Top of the Burner

This article covers the topic of temperature measurement on top of a gas burner fire in order to recognize pot removal from a gas burner and subsequently, to cut off the gas supply. The possibility of applying a factory-mounted thermocouple was investigated with the assumption that its output signal could be used to detect the presence of a pot on a gas burner. However, the characteristic of such a thermocouple is not fully linear and as the research has shown that such a thermocouple would not fit enough for the assumed purpose, thus another sensor needs to be used. Therefore, in this paper, the linear thermocouple and IR diode are used. The best localizations of theses sensors were investigated in order to obtain a signal suitable for the pot presence recognition over the burner. These investigations are supported by the use of an infrared camera. In the investigations, the temperature changes also caused by casual air blast or caused by increasing and decreasing the valve opening are recorded and analyzed. Finally, the changes of the thermocouple’s signals are used as an input signal to propose an algorithm for pot absence recognition over the burner. The microprocessor-based circuit with a control unit for detection of the pot absence is designed, built and investigated.

The Use of Thin Film Thermocouples to Determine the Thermal Conductivity and Young's Modulus of Coatings and Interfaces

Abstract Linear and differential thin film thermocouples, typically 500-1000Å thick, were fabricated on flexible polymer and paper substrates by thermal evaporation. Both types of thermocouples had thermal sensitivities of approximately 4 μ V/°C, for temperatures between 20°C and 40°C, on the paper and polymer-coated paper substrates. The transverse thermal conductivity (kt), i.e., thermal conductivity in the direction perpendicular to the plane of the films, of polyimide (Kapton-H®) films, of a clay-coated paper, and of a polystyrene coating on paper were determined by depositing linear thermocouples on both sides of the films and raising the temperature of one junction and measuring the heat flux and, at equilibrium, the temperature of the other junction. Shear and Young's moduli of the polymer films were estimated from the measured thermal conductivity values, assuming the Debye model of thermal conductivity.

A three-wire iron/copper/constantan linear thermocouple

A simple method is described for combining two thermocouple EMFs such that over any chosen range, the quadratic temperature-dependence term is eliminated. The resulting 'linear' output is suitable for many applications, such as thermoluminescence, differential thermal analysis (DTA) and ionic thermocurrents (ITC), where a virtually constant heating rate can be produced using this thermoelectric monitor and a voltage ramp feedback control. The characteristics are given over the range -100 to 0 degrees C for a combination of iron/constantan with 0.885 potentially divided copper/constantan, and a circuit is demonstrated whereby the sensor junctions of the combination are reduced to a single three-wire electrical contact.