Humidity Calibration Solutions - Michell Instruments

Calibration InstrumentsHumidity Calibration SolutionsThe Importance of Regular CalibrationThe reliable operation of a hygrometer and indeed anymeasuring instrument, can only be verified by periodiccalibration against a dependable reference system. Allhygrometers from Michell Instruments are delivered with acalibration certificate, but this alone will not guarantee themeasurement performance throughout their life. Exposureto contaminants within the measurement of gas can causemeasurement performance errors. To have confidence inthe performance of a sensor it must be verified by periodiccalibration.Michell Instruments Calibration ServicesMichell’s UKAS (United Kingdom Accreditation Service)laboratory was established back in 1986 and was the firstlaboratory in the UK to be accredited for the dew pointcalibration of hygrometers. The capability of the Calibrationlaboratory has been maintained and developed over the yearsand Michell can now offer calibrations over the range –90°Cto +90°C dew point with a best measurement capability of±0.15°C dew point. In addition to this Michell can providetraceable calibrations to NIST (National Institute for Standardsand Technology – USA).Calibration StandardsEach country will hold its own National Standard for dewpoint and humidity. This may be a primary standard. Othercalibration facilities will have reference instrumentationcalibrated against the Primary Standard and use this as theirstandard. In this approach a pyramid structure is generated.This structure gives confidence in the calibration process astraceability of calibrations is visible.Calibration PyramidNationalStandardPrimaryStandardNational HumidityStandard @ NPLBackground to Michell InstrumentsMichell Instruments is the international leader in the field ofmoisture and humidity measurement solutions. With over30 years experience, Michell designs and manufactures awide range of transmitters, instruments and system solutionscapable of measuring trace moisture, humidity and dewpoint in a vast range of applications and industries rangingfrom compressed air, power generation, process, oil and gas,pharmaceutical and many more.With a fast growing international subsidiary and distributionnetwork, the Michell Group provides solutions in moisture andhumidity for the most demanding applications worldwide.Michell uses three key dew point measurement technologies intheir products:• Impedance method using a ceramic tile which deliversunrivalled speed of response and robustness.• Chilled Mirror method which has been incorporatedinto advanced, precision instruments for industrial andlaboratory use.• Quartz crystal technology for a high precision, fastresponding moisture measurement with self-calibration.Applications for calibration instruments• Metrology Laboratories• Meteorology Laboratories• Calibration Laboratories• Industrial Gas Producers• Pharmaceutical Companies• Humidity Sensor / Instrument Manufacturers• ... and many moreReferenceStandardWorkingStandardMeasuringInstrumentSecondaryCalibrationAccreditedCalibrationTraceableCalibrationNPL CalibratedhygrometerS4000Dew-pointGeneratorDG-2Hygrometerunder testEasidew TX© 2010 Michell Instruments