This simple principle is governed by the controlled feedback loop of one or more temperature sensors within the instrument.
A temperature sensor is used to continuously monitor the thermal energy radiating through a heating chamber. The method by which the sensor achieves this is dictated by the device architecture, which generally falls into one of two groups: thermistors and thermocouples. While differing significantly in design, each of these temperature sensors monitors the conditions of thermal processing equipment using electrical signals.
Thermistors measure temperature as a function of changes in resistance. They exploit materials with strong linearity in terms of their temperature coefficients of resistance, which means they exhibit a proportional change in electrical resistance when subjected to temperature changes. They typically utilize high-purity conductive metals like platinum (Pt), which displays a positive temperature coefficient of resistance. This means their electrical resistance increases alongside increasing temperatures.
To develop a measurable output voltage, temperature sensors that operate on the principles of resistance must be supplied with a constant current. Thermal variations in the sensing element will register as changes in the output signal. This is then used to adjust and maintain optimal processing conditions, either manually with in-field temperature controllers, or autonomously using a controlled-loop feedback system. However, thermistors are limited to low-temperature thermal processing given their inferior heat-resistant properties compared to thermocouples – particularly mineral insulated thermocouples.
The humble thermocouple is the tried-and-tested temperature sensor of industrial heat treatment markets worldwide. These devices are made by forming two junctions between two wires of dissimilar metals: a measurement and a reference junction. An electronic controller measures differences in temperature between these two points to accurately gauge the ambient temperature in the heating chamber.
This proven architecture is elevated by the implementation of a high-performance mineral coating, which insulates metal-sheathed thermocouple conductor cables with compacted magnesium oxide.
Among the many benefits of thermocouple temperature sensors are the myriad material combinations available for these temperature-sensitive junctions. This unlocks a plethora of architectural arrangements, with temperature capabilities ranging from -196°C – 1600°C (-320°C – 2912°F).
TT Electronics supplies a choice of mineral insulated thermocouple cables with a selection of both hot-end junctions, cold-end terminations, metal sheath material types, thermocouple alloy types, and cable dimensions. Our thermocouples are subsequently suitable for extremely high-temperature material processing applications, with rugged, heavy-duty designs available for long service lives in industrial thermal processing.
TT Electronics specializes in the development, supply, and fine-tuning of advanced electronic solutions for various industrial applications. Our expertise in the field of temperature sensor technologies encompasses a range of services and a full brochure of high-performance products that can assist in the optimization of thermal processing at industrial scales.
Whether you need a new temperature sensor retrofitting to existing thermal processing equipment, or simply feel that your established sensors require calibrating, contact us today to book a consultation.