KH20 Krypton Hygrometer
10
However, the scaling over a typical flux averaging period is small. Thus, water
vapour fluctuation measurements can still be made with the hygrometer.
To see if the source tube window has been scaled, get a clean, dry cotton swab
and slide it across the source tube window. The scale is not visible to the naked
eye, but if the window is scaled, you will feel a slight but noticeable resistance
while you slide the swab across the window. There will be little resistance if the
window is not scaled. If you determine the window is scaled, you can clean it
with a wet cotton swab.
Use distilled water and a clean cotton swab to clean the scaled window. After
cleaning the window, slide a clean, dry swab across the window to confirm the
scale has been removed.
You can use the water vapour absorption coefficient for scaled
window from the calibration sheet if the window will be allowed to
scale during measurements.
6.5 Older KH20
The older version of the KH20 used to suffer permanent damage when exposed to
water, due to corrosion and loss of vacuum within the tubes. The new version of
the KH20 has employed a new sealing around the window to prevent this type of
damage.
6.6 Calibration
For quality assurance of the measured data, Campbell Scientific, Inc. recommends
the KH20 be recalibrated every two years. Please contact Campbell Scientific,
Inc. to obtain an RMA number for recalibration.
For more information on the calibration process, refer to Appendix A of this
manual.
NOTE
