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[September 2000]
Michell Launches HG1 for Portable, Traceable Humidity Calibration
Michell Instruments (Cambridge, England) is launching a new, portable humidity calibrator, designated the HG1, to monitor the accuracy and performance of relative humidity probes, cooled mirror and capacitance dewpoint sensors. The HG1 is traceable to NPL and NIST and enables dewpoint instruments to be calibrated quickly, says Michell, either on site or in a calibration laboratory, to ensure that existing equipment continues to meet increasingly stringent quality regulations.
Incorporating an integral gas dryer, humidification system, sample chamber and air pump, the HG1 measures dewpoint within the range -30°C to +20°C and relative humidity between 2% and 95%, at operating temperatures between 10°C and 35°C.
In practice, the HG1 splits a source of dry air into two streams, one of which is humidified by bubbling it through a water saturator while the other is passed through a gas dryer to remove any remaining moisture. The two streams are then mixed volumetrically to produce an air sample with a specific dewpoint within the humidity chamber.
A Michell Dewmet TDH cooled mirror hygrometer is used as a reference instrument, confirming the precise dewpoint, relative humidity and temperature within the chamber, for comparison with the measurement data produced by the instrument under test.
The HG1 is supplied as a complete, ready to operate system, which requires only electric power and an occasional top-up of the saturator with distilled water to operate. The calibrator can be supplied with a wide range of optional facilities, including internal and external dry air feed and pressure control to meet the requirements of each application.
Website: www.michell.co.uk
ENDS