Wet & Dry Buld Hygrometers
Consisiting of dry and wet alcohol filled glass thermometers fixed on a panel .
By differential indication between these thermometers , humidity can be read from the table mounted on a panel .
Used to measure the relative humidity in the Cargo hold .
Basically, two mercury thermometers are used in this hygrometer. One thermometer feels the surrounding air temperature.
This thermometer is called a dry bulb thermometer. Another mercury thermometer is used to measure the water temperature at the temperature of a dry bulb thermometer.
This thermometer is called the wet-bulb thermometer. A sleeve of muslin cloth or wicking dip is fitted over the feeling end of the wet-bulb thermometer.
The free end of this muslin sleeve dips in the reservoir or container filled with distilled water. The temperature measuring scale is mounted close to each thermometer.
