Temperature Sensor Calibration

Temperature Sensor Calibration

Have a look: "Boiling Water - Periodic Table of Videos"

 

(At YouTube: https://www.youtube.com/watch?v=sCh2T9axLyY)  

THE INTERNATIONAL TEMPERATURE SCALE OF 1990 (ITS-90)

Yes, there is an "official" temperature scale. It's based on the true, thermodynamic temperature scale, but the real, working temperature scale is something practical which can be repeatably produced anywhere in the world given the correct practices and equipment. 

It's a lot like the freezing and boiling points of water but developed and refined to a higher degree (pardon the pun). It is revised periodically as our technical abilities improve and as those who specialize in the field of metrology (measurement science) are able to come to some consensus. 

 The link above provide detailed information about the newest revision of the temperature scale used in calibration and measurement. This is the scale that the National Measurement Institutes (NMIs) or "labs", or those affiliated with them, refer to in the calibration certificates of reference devices. 

 This could be for sensors used in corporate or university or other measurement laboratories which provide a more local service such as to working instruments in a process plant or experimental apparatus. The International Temperature Scale of 1990 (ITS-90 "A Guide to the Realization of the ITS-90 at BIPM". 

The official publication of the International Temperature Scale of 1990 (ITS-90) gives a concise definition of temperatures T90 and is highly prescriptive. To accompany the text, supplementary information concerning the practical realization of the scale was published in 1990 by the BIPM in a monograph entitled Supplementary Information for the ITS-90; this monograph provided the non-prescriptive details in a comprehensive form. 

 It is interesting that most of the fixed reference points on the ITS-90 are melting and triple point temperatures of pure materials. 

One example used to be the Ice Point, 0 Degrees Celsius. But it was replaced in 1967 by an even more precise temperature called the Triple Point of water. The name of the Centigrade temperature scale was officially changed to Celsius at the same time.

 In the early days of thermometry, the Boiling Point of water was also used as a key reference temperature for the Celsius Scale. It is nominally 100 Degrees Celsius (hence 100 degrees or the Centigrade temperature scale). However, it was found that the boiling reference point was not as stable as either the freezing or triple points; it is quite sensitive to the pressure on it from its surroundings. 

 An excellent video on the subject was created by the folks in responsible for the Periodic table of Videos at the School of Chemistry at The University of Nottingham in the UK, It is shown at the top of this page along with a YouTube link.   https://www.nottingham.ac.uk/periodicnottingham/elements.aspx.

Some (by no means all) Suppliers of Temperature Calibration Equipment, Services and/or Training in Sensor Calibration

NIST Thermometry Calibration Services

Some Commercial Temperature Sensor Calibration Services & Calibration Products

1. Advanced Sensing Products (USA) A secondary standard PRT and precision RTD probe manufacturer. They make own RTD elements to completely control product quality. Provide NIST traceable calibration services with temperature ranging from -189 to 850 °C. Customers are in metrology, instrumentation, power industry, turbine manufacturers, and the military.
2. AMETEK Sensors, Test & Calibration A comprehensive range of pressure, temperature, and process calibrators, pressure gauges, deadweight testers, temperature sensors & more
3. AMETEK-Land  A world leading manufacturer of monitors and analysers for industrial infrared non-contact temperature measurement, combustion efficiency and environmental pollutant emissions
4. ASL (Automatic Systems Laboratories) is the global market leader in the manufacture and supply of temperature instruments from high accuracy hand-held thermometers to metrological level temperature bridges and has been part of the WIKA family of Calibration Technology products since 2013.
5. BurnsEngineering, Inc. Burns Engineering offers the best in Secondary Standard Platinum Resistance Thermometers, precision comparison RTD's and calibration services.
6. Cole Parmer Instruments (USA) InnoCal®, a division of Cole-Parmer, specializes in instrument calibration. Their accredited metrology laboratory has helped thousands of customers meet ISO, FDA, USDA, EPA, GLPs/cGMPs and other quality standards..
7. GEC Instruments (USA) Precision thermocouple instruments connect to a PC via RS232 serial port or USB. A unique internal reference junction system provides CJC (Cold Junction Compensation) of 0.003 °C or better on all channels. Windows software with built in calibration wizard enables user calibration of individual thermocouples to attain overall system measurement accuracy of better than ± 0.05°C, including thermocouple wire error. GEC Instruments also provides custom thermocouples and custom multiple point thermocouple calibrations to attain measurement accuracies of ± 0.02 °C (± 0.01 °C at temperatures near ambient) on all channels.
8. Hart Scientific(USA) - Hart Scientific temperature calibration is part of Fluke Calibration
9. Insco Metrology (USA) INSCO has 45 years of EXPERIENCE in process control, instrumentation, electric engineering, maintenance, and installation and calibration services. INSCO laboratories are located in Miami (USA), Puerto Rico and Mexico (DF).
10. Isotech (USA & UK) Isotech is a world leader in temperature metrology. With over 30 years experience in the design, manufacture and practical use of precision temperature calibration standards,
11. Pond Engineering Laboratories (USA) Pond Engineering manufactures cells and maintenance systems to realize every Defining Fixed Point on the ITS-90 - from Argon through Silver.
12. Process Instruments, Pittsburgh, PA (USA) Supplier of equipment and services to industry for many years, traceable to NIST for all types of temperature sensor calibrations.
13. Spectrodyne (USA) Spectrodyne's full service infrared standards laboratory specializes in the repair and calibration of most brands of optical pyrometers and infrared thermometers.
14. Tempsens Instruments India Accredited Calibration services are provided for all kind of temperature sensors and furnaces including pyrometers for temperature range -196 °C to 2900 °C.
15. Thermo Gauge Instruments Inc.(USA) Precision Blackbodies are used worldwide by those who know thermal radiation sensors and their calibration requirements.