Dry And Wet Bulb Psychrometer Pdf

A psychrometer measures humidity by taking both a wet bulb and a dry bulb temperature reading.

Dry and wet bulb psychrometer pdf.

Astm standard e 337 02 2007 reviews in great detail the wet and dry bulb technique. Difference between the dry bulb and wet bulb temperatures related to the ambient humidity. Determine the properties of the air at state point 2 and compare them with those at state point 1. Relative humidity is measured using a device called a sling psychrometer this consists of 2 side by side conventional thermometers one of which the wet bulb thermometer has a wetted wick placed at the bottom the other the dry bulb thermometer has no wetted wick.

Where a is the psychrometric coefficient which is independent of the evaporating surface area i e. Is cooling whereas wet bulb temperature represents how much moisture the air can evaporate. Relative humidity can be found by subtracting the temperature on the wet bulb thermometer from the temperature on the dry bulb thermometer and using a relative humidity chart. Dry bulb temperature and 57 c wet bulb temperature experiences a temperature drop of 3 c as it passes through the 1 2 m wide stack of lumber.

When the psychrometer is swung around by its attached chain or handle the air causes the water on the wick to evaporate which. With those two values known the other properties of the air including its moisture content can be determined by computation or by reading a psychrometric chart. A psychrometer consists of two thermometers with the bulb of one thermometer covered with a wet cloth. The uncovered thermometer measures dry bulb temperature while the one covered with wet cloth measures wet bulb temeprature.

One is a wet bulb and the other is a dry bulb. The wet bulb dry bulb technology psychrometer introduction wet and dry bulb temperature measurement is a commonly used and widely accepted technique for controlling relative humidity in environmental chambers. To make a wet bulb thermometer wrap a piece of white porous cloth a hollow white shoelace is ideal which has been. Mengshen digital psychrometer handheld backlight temperature humidity meter gauge with dew point and wet bulb temperature battery included m350 4 0 out of 5 stars 148 32 99 32.

Water evaporates from the wet cloth which lowers the temperature. The size of the wet bulb wick covering but is slightly dependent on ventilation rate and to an even minor degree on psychrometer design size and dimension of the dry and wet bulb ambient temperature and rh however when ventilation is in excess of 2 5 m s 1 and particularly in the. A sling psychrometer consists of two thermometers. Wet bulb dry bulb jma type aspirated psychrometer 1 2 psychrometric method.