In industrial applications involving the use and measurement of liquids, accurate temperature sensing is of crucial importance. Accurate maintenance of liquid temperatures is vital for everything from the proper brewing of beer to the prevention of meltdowns in nuclear power plants. Because of the complex nature of these industrial applications and the need for extreme precision, simple thermometers like those you might buy in a pharmacy won’t suffice – more sophisticated implements are required. But how do these industrial temperature sensors work? Let’s take a look at two of the most popular kinds: thermocouples and resistance temperature detectors (RTDs).
How Thermocouples Work
Thermocouples are devices that use two conductors or semiconductors which contact each other at one or several points. A voltage is produced when the temperature of one of these points differs from that of another. This voltage can then be measured and used to determine the surrounding temperature.
Thermocouples are not as accurate as some other forms of industrial temperature sensors, but they are capable of measuring a wide range of temperatures, from hundreds of degrees below zero to as much as 3000°C.
How Resistance Temperature Detectors (RTDs) Work
Most often made from narrow wires of conductive metals like platinum, nickel, and copper, RTDs measure temperature by maintaining a constant electrical current and measuring the resulting voltage against the temperature. RTDs are far more accurate than thermocouples, but are best suited for measuring temperatures no greater than about 600°C.
Custom
Temperature Sensors from SMD Fluid Controls
SMD Fluid Controls offers both custom and off-the-shelf temperature sensing solutions including both thermocouples and RTDs. SMD’s FT20 custom temperature switches are ideally suited for engines, pumps, compressors, and more, boasting both the accuracy and durability required for such applications. For a more versatile single unit, the FM22 is a combination liquid level and temperature sensor perfect for combining uses to minimize tank intrusion.