Wet And Dry Bulb Hygrometer Principle

As the water around the wet bulb evaporates the bulb cools down because the water absorbs heat from its surroundings as it changes phase.

Wet and dry bulb hygrometer principle.

Moreover it is the most common hygrometer and easily usable. Dry and wet bulb hygrometer. Hygrometer contains two thermometers one is called dry bulb and second as wet bulb. As our testing lab is not air conditioned so the dry bulb hygrometer is of course need for the accurate of all expects.

Dry bulb reading wet bulb reading difference r h. At a lower humidity water evaporates more actively so that the wet bulb temperature lowerssharply. The wet bulb thermometer has it s bulb wrapped in a tight fitting muslin cloth material wicking which is soaked in. The principle behind a psychrometer is fairly simple.

Bulb as the water evaporates and the wet bulb temperature becomes lower than the air dry bulb temperature. In order to measure the dry bulb and wet bulb temperature the psychrometer frame glass covering thermometer arrangement is rotated at 5 m s to 10 m s to get the necessary air motion. This type of hygrometer uses two basic mercury thermometers one with a wet bulb one with a dry bulb. One is dry and the other is kept moist by wrapping the bulb in a wet piece of cloth.

The aspirated psychrometer measures humidity by measuring the difference between the dry bulb temperature and wet bulb temperature. Evaporation from the water on the wet bulb causes its temperature reading to drop causing it to show a lower temperature than the dry bulb. Masons wet dry bulb hygrometer is used to calculate the water vapour content relative humidity of air at a given temperature. A hygrometer is an instrument used to measure the amount of water vapor in air in soil or in confined spaces.

An important condition is that correct accurate measurement of wet bulb temperature is obtained only if air moves with velocity around the wet wick. Wet and dry bulb psychrometers are the most simple and common way of measuring humidity. 76 70 65 70 76 70 76 70 70 76 10 71 9. Get it thu sep 24 tue sep 29.

The instrument is made up of two indentical thermometers one a wet bulb and the other a dry bulb. From table mean r h. 4 0 out of 5 stars 1. The device contains two thermometers.

According to their names dry bulb remains dry in the air and the et bulb is surrounded by a cotton wick that is dipped in the water. Humidity measurement instruments usually rely on measurements of some other quantities such as temperature pressure mass a mechanical or electrical change in a substance as moisture is absorbed.