The change in temperature can cause a change in the resistance value of metals. Some metal components have a good linear relationship between the resistance value and temperature change, such as platinum thermistors and copper thermistors, which are often used as temperature measuring components. By only measuring the resistance value of metal components, the temperature value of the metal components can be obtained. This type of thermal resistance temperature sensor outputs a resistance signal, the most common being a Pt100 platinum thermal resistance signal. The secondary instrument or central control room only needs to display the temperature corresponding to this resistance value based on the resistance signal transmitted by the temperature sensor.
Thermocouples use electromotive force signals to determine temperature. Two different metals are welded together at both ends to form a circuit, and one end is used as the measuring end. When the temperatures at both ends are different, thermoelectric electromotive force is generated in the circuit. Conversely, changes in thermoelectric electromotive force also indicate changes in temperature at one end, such as platinum rhodium 10 platinum. By connecting a secondary instrument, the corresponding temperature value can be displayed.
According to different usage scenarios, thermistors or thermocouples may have different protections and appearances. For example, temperature sensors commonly used for motor temperature measurement differ between stator thermistors and bearing thermistors. The stator thermal resistance is used to measure the temperature of the stator. The commonly used temperature sensor style for Huaye explosion-proof instruments is an embedded thermal resistance. The protection of the thermal resistance is a long plate, buried in the temperature measurement position, and the lead wire is connected to the thermal resistance signal and connected to the secondary instrument. The thermal resistance of bearings is used for temperature measurement bearings. The commonly used temperature sensor style for Huaye explosion-proof instruments is a face type platinum resistance. The motor temperature measurement position has a hole, and the temperature sensor is fixed by inserting a platinum resistance probe protected by a stainless steel protective tube into the temperature measurement hole and fixing it with screws or flanges. Lead out the thermistor signal and connect it to the secondary instrument.
Usually, temperature sensors include optional components such as temperature measuring elements, protective tubes, wiring terminals, junction boxes, and insulation sleeves, and installation fixing devices are also included. This is not only the classification of temperature sensors, but also extends to explosion-proof temperature sensors and ordinary temperature sensors based on whether the junction box is explosion-proof; And temperature sensors with protective tubes, junction boxes, and terminals are also called armored temperature sensors, such as armored platinum thermistor temperature sensors and armored thermocouple temperature sensors; There is even a habit of referring to temperature sensors with temperature transmitters as temperature sensors, and those with instrument displays as temperature sensors (nowadays, industrial temperature measuring instruments are mostly integrated with on-site display and remote transmission of temperature signals).
There is also an integrated temperature sensor, which consists of temperature measuring elements, protective tubes, junction boxes, and other complete structures, roughly the same.
These terms only vary depending on the classification or usage habits of different manufacturers and users. Essentially, temperature sensors convert on-site temperature signals into easily transmitted resistance signals, electromotive force signals, or current signals converted by temperature transmitters. They are usually composed of temperature sensing elements, temperature sensing element protection parts, junction boxes, terminals, and installation fixing devices. For some other needs, Insulation sleeves, temperature transmitters, leads, etc. will be added.