Dry And Wet Bulb Psychrometer Pdf

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.

Dry and wet bulb psychrometer pdf.

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. 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. 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. One is a wet bulb and the other is a dry bulb.

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. When the psychrometer is swung around by its attached chain or handle the air causes the water on the wick to evaporate which. Since both the thermometers are placed side by side the mositure from wet wick may affect the readings of dry bulb thermometer to avoid this the wet bulb thermometer is placed at the lower level. Meteorological instrument center japan meteorological agency an operational equilibrium temperature exists for the instrument depending upon.

Water evaporates from the wet cloth which lowers the temperature. Wet bulb dry bulb jma type aspirated psychrometer 1 2 psychrometric method. A psychrometer consists of two thermometers with the bulb of one thermometer covered with a wet cloth. Difference between the dry bulb and wet bulb temperatures related to the ambient humidity.

Astm standard e 337 02 2007 reviews in great detail the wet and dry bulb technique. Is cooling whereas wet bulb temperature represents how much moisture the air can evaporate. 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. The uncovered thermometer measures dry bulb temperature while the one covered with wet cloth measures wet bulb temeprature.

To make a wet bulb thermometer wrap a piece of white porous cloth a hollow white shoelace is ideal which has been. Determine the properties of the air at state point 2 and compare them with those at state point 1. Where a is the psychrometric coefficient which is independent of the evaporating surface area i e. A sling psychrometer consists of two thermometers.