For determination of relative air humidity learn the actual pressure or density of steam at this temperature, divide into value of pressure of saturated steam at this temperature which can be found in the table and increase by 100%. Also relative air humidity can be found depending on a difference of indications of dry and damp thermometers or change of length of a hair depending on humidity.
It is required to you
- two identical thermometers, gauze piece, hair psychrometer, psikhrometrichesky table and table of definition of a dew point.
Instruction
1. Determination of relative humidity through a point to a rosyizmerta air temperature and determine pressure of saturated steam by the table at this temperature. After that select test of air and cool it, constantly controlling temperature until water vapor in it begins to be condensed, forming dew. Take temperature in this point and determine pressure of saturated steam by the table. It will be to equally actual vapor pressure at an initial temperature. After that divide pressure of the saturated steam received when cooling into pressure of saturated steam at this temperature, and increase result by 100%. Relative humidity as a percentage will be result.
2. Determination of relative humidity by two you termometramivozmit two identical thermometers. Better liquid mercury thermometers will approach. Reel up a gauze on a vial of working liquid of one of them then plentifully moisten it with water. Having waited some time, take readings from thermometers in degrees Celsius. Then find the difference of temperatures on the damp and dry thermometer, indications of the damp thermometer will be or same, or below, than dry. Find a column of indications of the dry thermometer in the psikhrometrichesky table and find the closest to what showed measurement. Then on a line find value which corresponds to the calculated difference of indications of dry and damp thermometers, in a cell there will be a relative air humidity as a percentage.
3. Determination of relative humidity hair a horsehair changes a gigrometromposkolk the length depending on humidity of air, pull it and attach to a sensitive dynamometer. It is possible to determine relative air humidity by force of a tension. This measurement will be the least exact.