Equipment used for moisture testing includes various types of hygrometers, each designed for specific applications. One widely used instrument is the aspirated psychrometer, which provides accurate and reliable measurements of humidity.
An aspirated psychrometer consists of two thermometers: a wet-bulb thermometer and a dry-bulb thermometer. The wet-bulb thermometer’s bulb is covered with a wick saturated with water, while the dry-bulb thermometer remains dry. As air is passed over the thermometers using a fan or aspirator, evaporation occurs from the wet-bulb, cooling it. The difference between the wet- and dry-bulb temperatures is known as the wet-bulb depression and is directly related to the moisture content of the air.
Aspirated psychrometers are commonly used in various industries and applications, including: