- - mercury thermometer;
- - sealed container;
- - table depending on the saturated steam temperature;
- - psychrometer.
for direct measurement of moisture, take a sample air in a sealed vessel and begin to cool it.At a certain temperature in the vessel will be mildew (vapor condenses), write down the value of the temperature at which this occurs.On special table for the density of saturated stea
m at the temperature that it is condensed.This is the absolute humidity air , which selects the sample.
Take a sensitive mercury thermometer, mercury bubble wrap cloth.Remove it from the evidence after it comes into thermal equilibrium with the ambient air.According to the table to determine the density of saturated steam at a temperature that the thermometer shows.This is the absolute humidity , but the value is not very accurate.
Calculate absolute humidity at a known relative humidity.This value is measured in percentage and indicates how many times the actual density of the water vapor in the air is less saturated at this temperature.To determine the absolute humidity measure the temperature of the air .Then, the density of saturated steam table get this value for the measured temperature.To find the absolute humidity , relative humidity φ multiply by the density of the saturated vapor at a given temperature ρn and divide by 100% (ρ = φ ∙ ρn / 100%).
Example Relative humidity at 20 ° C is 45%.To get the absolute humidity , find the density of saturated steam at a temperature of 20 ° C, which is air.This value of 17.3 g / m³.After that apply the formula for the calculation of absolute humidity ρ = 45 ∙ 17,3 / 100 = 7.785 g / m³.This is the absolute humidity air .
If the relative humidity is unknown, measure it with a special device called a psychrometer.
- absolute humidity