Wet Bulb Dry Bulb Thermometer
Wet bulb temperature can be measured by using a thermometer with the bulb wrapped in wet muslin.
Wet bulb dry bulb thermometer. The concept behind a wet bulb thermometer is simple but keep in mind that to measure relative humidity it has to be used in conjunction with a dry bulb thermometer. Wet bulb temperature t wb can be measured with a standard thermometer with some wet clothing cotton or similar around the bulb. The temperature of the air measured by the ordinary thermometer is called as the dry bulb temperature of air commonly referred as dbt. The wet bulb temperature wbt is the temperature read by a thermometer covered in water soaked cloth wet bulb thermometer over which air is passed.
Dry bulb temperature and. Temperature of the ordinary air measured by the thermometer when it is covered by wet cloth or wick is called as the wet bulb temperature commonly referred to as wbt. It includes a dry bulb thermometer a wet bulb thermometer and a psychrometric chart a graph that plots the relationships between the dry and wet bulb temperature relative humidity and dew point at constant pressure. By definition wet bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only.
Air humidity can be estimated by measuring. Dry bulb temperature t db can be measured with a simple thermometer as shown above. At lower humidity the wet bulb temperature is lower than dry bulb temperature because of evaporative cooling. At 100 relative humidity the wet bulb temperature is equal to the air temperature dry bulb temperature.
The wet bulb temperature is the adiabatic saturation temperature. Combining the dry bulb and wet bulb temperature in a psychrometric diagram or mollier chart gives the state of the humid air. The dbt and wbt of the air are measured by a special thermometer called sling thermometer. The wet bulb temperature is always lower than the dry bulb temperature but will be identical with 100 relative humidity the air is at the saturation line.