Application Notes
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Hydromette BL Compact TF-IR
device may only be exposed to temperatures above 50 °C for short
periods. False measurements can arise from shielding with body
parts (e.g. hand) as well as blowing or speaking/breathing in the
direction of the sensor.
The setting time of the air temperature sensor in moving air is
approx. 3 minutes for 90 % of the temperature difference.
The air temperature sensor adapts to the surrounding temperature
even when stored (not switched on).
4.2.1
Dew Point Temperature
The dew point is the temperature at which the air is saturated with
water vapour. Condensation occurs below this temperature. The
dew point generally lies below the air temperature, except with 100
% r.h, where both temperatures are the same.
The dew point is dependent on the air temperature and water
vapour partial pressure and equal to the temperature whose
saturation pressure is equal to the water vapour partial pressure
present. The water vapour partial pressure is calculated as follows:
𝑊𝑎𝑡𝑒𝑟 𝑣𝑎𝑝𝑜𝑢𝑟 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 =
𝑟𝑒𝑙. ℎ𝑢𝑚𝑖𝑑𝑖𝑡𝑦 𝑥 𝑤𝑎𝑡𝑒𝑟 𝑣𝑎𝑝𝑜𝑢𝑟 𝑠𝑎𝑡. 𝑝𝑟𝑒𝑠𝑠.
100
Further information can be found on the Internet.