Air humidity measurement
Calibration in climatic chamber by comparison with a reference
hygrometer: the dew point temperature is measured with a reference hygrometer.
The temperature measurement is performed with a reference thermometer put near
the sensor to be calibrated. The reference relative humidity is calculated from
those two measurements.
Measurement of temperatures
Three methods are used according to the field of temperature:
- Between -30 and +160°C, the calibration is performed
in a climatic chamber by comparison with a 100-ohm platinum
- Between -30 and +215°C, the calibration is performed
in an overflowing thermostatically controlled bath, by comparison with a 25 - ohm reference platinum resistance
thermometer. Depending on the temperature, the liquid used
is either alcohol, water or oil. The thermometer probe
must be at least 60 mm long for a diameter below or equal
to 6 mm,
150 mm long for a diameter over 6 mm.
- Between +200 and +1100°C, the calibration is performed
in a special furnace by comparison with a type S thermocouple.
The diameter of the thermocouple to be calibrated must be below 10 mm
and its length must be over 270 mm.
Measurement of air velocities
The calibration of the anemometers is performed in a wind tunnel,
by direct comparison with a reference.The reference device used by the laboratory over
the whole velocity range is a laser-Doppler anemometer (L.D.A.)
The calibration conditions are the same that for the one-function instruments.
Please refer to the corresponding information.
Measurement of pressures
The calibration of manometers or pressure sensors is performed by direct comparison
with a reference. The generated pressure is measured in parallel on the reference
and on the pressure sensor to be calibrated.
The calibration conditions are the same that for the one-function
instruments. Please refer to the corresponding information.