Measuring Dew Points Below -40°C (-40°F) - Michell Instruments Easidew Portable HP User Manual

Easidew Portable HP User's Manual
3.2 Measuring Dew Points Below -40°C (-40°F)
Due to the significantly lower levels of moisture present at dew points of this level, the
response times of the sensor will be significantly increased. The table below offers an
approximate guide to the times taken for the instrument to stabilize at a given dew
point (from a starting point of 10°Cdp (50°Fdp) ambient):
The Easidew sensor fitted to the Easidew Portable is designed and calibrated to measure
dew points as low as -100°C (-148°F). However, due to the large internal volume of
the sample block, the hygroscopic nature of the built-in filter, and the potential of the
gas fittings to trap moisture at very low dew points, we recommend that the Easidew
Portable is not used to measure dew points below -60°C (-76°F). Suitable alternative
solutions in our range would be the Easidew Online, Pura fixed installations, MDM300
Portable, or our cooled mirror range of instruments.
Michell Instruments
Target Dew Point
°C °F
-30 -22
-40 -40
-50 -58
-60 -76
OPERATION
T100 Response Time
(mins)
15
30
60
180
5