Thermal processing equipment uses several types of thermocouples to measure temperatures. These are broken into two main categories Base Metal types and Noble Metal types. The base metal category includes types K, N, J & E thermocouples these are typically used at lower temperatures and are very economical. The Noble metal category includes types B, R & S thermocouples these are used at higher temperatures and are more expensive but are more accurate and are available with “special limits” to provide the highest accuracy.
To satisfy many of today’s manufacturing standards (CQI-9, CQI-29, AMS-2750 and others) there is often a replacement or recalibration requirement, and these typically require base metal types to be replaced annually at a minimum and noble metal types every two years. Noble metal types can also be recalibrated by the manufacturer while the base metal types must be replaced. Just as these standards require replacement or recalibration of the thermocouple, they also require calibration of the temperature instruments that control your process. This service is often outsourced to an ISO 17025 accredited company that can provide the traceability that these standards require.
One very important note when using an outside calibration service is that the calibration that is being performed is an accuracy check between the installed temperature instrument and a calibrated instrument that can simulate the millivolt signal from the thermocouple that is brought in by the company providing the service. There is no check of the actual thermocouple itself or its accuracy in the calibration process therefore the replacement or recalibration requirement is there. Be sure that either your calibration provider or your maintenance department is replacing your thermocouples at the required frequency to avoid issues with controlling your process or meeting today’s standards.
If you have any questions or are looking for a service provider that understands these requirements, give us a call today 814-781-6355 or email [email protected].
