If the water vapour content of the air exceeds the maximum possible value of the absolute humidity at a given temperature, water will separate out in liquid form. This temperature is known as the dew point. For drying it is just as necessary for the air to be warm as to be dry. The amount of water vapour evaporated in a given time doubles, when the temperature is raised from 40oc to 60oc.
A reduction of relative humidity from 80 to 60 per cent can reduce the drying time by nearly half. As drying proceeds the drying speeds falls, since temperature and air movement can influence drying only in so far as the water inside the clay is able to reach the surface.
To be contd…………….
