Continuing my discussion of the psychrometric chart and how to use it, in my last column, I showed a psychrometric chart, plotting four points. Allow me to proceed with the topic by picking up our ongoing example and taking it further, by putting that air inside a piece of process equipment such as a dryer or oven.

Now that we are somewhat familiar with all of the data ranges and curves on the psychrometric chart, let's figure how to use it.

For each and every product, there is a representative curve that describes the drying characteristics for that product at specific temperature, velocity and pressure conditions. This curve is referred to as the drying curve for a specific product. Variations in the curve will occur principally in rate relative to carrier velocity and temperature.