In processing of textile products, it is important to be able to determine quickly when the products are sufficiently dry. The surface temperature of a “wet” product will change (rise) very slowly as constant heat is applied to the product.
This occurs because the moisture in the product absorbs much of the heat energy as it evaporates. At the point that the product becomes “dry’, however, the same constant heat supply will quickly raise the temperature until it reaches the same as the surrounding air, or higher if the heat source is radiation.
If temperature vs. time is plotted for a heated drying process, the target “dry” temperature point can clearly be seen as the beginning of a rapid rise in surface temperature.
