Accuracy and stability in the monitoring and reporting of machine and process temperatures is critical in many industrial environments. Special temperature monitoring equipment is needed in situations where such devices are exposed to harsh and sometimes extreme conditions on a continual basis.
The wrong temperature sensors in the wrong locations can negatively impact operations and lead to circumstances that threaten both the efficacy of equipment and safety of surrounding personnel. Therefore, temperature measuring probes and sensors must be carefully selected for their level of endurance and ability to perform consistently within a given setting.
The “Big Three”
There are a number of different temperature probes as well as measuring and monitoring devices specifically built for hard-working industrial machinery and processes that generate intense heat. But the industry-wide “mainstays” are the thermistor, thermocouple and the resistance temperature detector (RTD).
Thermocouples are rugged and accurate. They are constructed of various metal alloys and contain two contact points made from disparate metals. Temperature readings are generated from the difference between the measurements of the two contact points and then delivered to a temperature indicator. Thermocouples can measure temperatures at a wider range than thermistors or RTDs, but are less accurate and more prone to noise interference.
Thermistors are very accurate at limited temperature ranges, but are not as sturdy as thermocouples. RTDs also offer a high degree of precision and durability. But like thermistors, they are incapable of withstanding the exceedingly high temperatures and mechanical strains under which thermocouples are able to perform.
Each of the smart sensors mentioned above can be customized for increased durability, accuracy and a wider temperature-measuring range. This can be accomplished through the use of protective sheathing and “signal conditioning” among other techniques.
With each type of sensor having its own set of advantages and disadvantages, operations managers and engineers must be discerning in their choice of which device to use in a particular situation.