Pictures can easily show the difference.
Learn more about pests or mechanical dryers and conquer the confusion over generic terms. Browse through the gallery and see for yourself what you specifically want. The picture of a fluidized-bed dryer for instance, can give you a more concrete information than merely reading a bunch of descriptive paragraphs.
The Bureau of Postharvest Research and Extension (BPRE) now brings you an online photo library where you can view, download and watch a slide show of postharvest and mechanization technologies as well as BPRE-related activities.
For free.
Just rein a mouse with your fingers and click at:
http://www.bpre.gov.ph/photolibrary.html