Dry wet bulb how to calculate the relative humidity?

The dry wet bulb also called psychrometer. To heat through water evaporation cooling and evaporation speed ( That is, how much cool) And when the relative humidity of the air on this principle. Its structure is to use two thermometers, one of the ball wrapped in white gauze, gauze to the other end in the sink, namely by capillary action that keeps in wet gauze, this is known as wet bulb. Another not with gauze bag and thermometer dew in the air, of dry bulb ( Dry bulb temperature temperature) of 。 If air water steam saturation, wet the surface of the ball constantly evaporates water vapor, and absorbs the heat of vaporization, therefore, indicated by the wet bulb temperature is lower than the dry bulb. The air is dry, The lower the humidity) , the faster evaporation, unceasingly absorbs the heat of vaporization, as shown in the wet bulb temperature is reduced, and the difference between dry bulb. When the water steam in the air, on the other hand, the saturated state, water is no longer evaporation, nor absorbs the heat of vaporization, wet bulb and dry bulb temperature, which will be equal. When using, should be dry and wet place apart from the ground 1 meter. 2 to 1. 5 meters high. Read the temperature difference, indicated by the dry, wet two goals by the thermometer attached table can be detected when the relative humidity of the air. Because the evaporation of water of gauze of wet ball package by fast, and not only when the relative humidity of the air, and air velocity are concerned. So dry wet bulb attached table only applies to the specified wind speed, not any application. 【 For example: 】 Soaking temperature is 22 ℃ dry, wet soaking temperature is 16 ℃ & ndash; — Can reading meter first shown in a column to find dry bulb temperature 22 ℃; — — Reading meter again in another column of dry and wet dip 6 ℃ temperature difference; — — 2 columns intersect values for 54, is the relative humidity is 54%.