Tray dryer is the generally a device that is used to drying the wet products of crude drugs, more like, chemicals, powders or the granules etc. as we provide in its simplest form; the dryer in this category is a cabinet with a heater at the bottom i.e. laboratory oven. The tray dryer is that; of the directed circulation form, in this dryer air is heated therefore it also gets directed through the material in a proper flow. The material which is to be dried is spread on the tiers of the trays. These trays used to have solid ,wire mesh bottoms. This paper might be used as a disposable tray liner to reduce cleaning time as well as to prevent contamination of the product, respectively.
In a modern tray dryer a uniform temperature plus an air system to be maintained by the use of a well insulated cabinet with strategically placed fans and heating coils. There’s an alternate arrangement of the sheleves so that air can flow constantly and with proper speed without any obstructions. Heater is fixed in such way that the air is reheated before passing over each shelf. When the air passes over each shelf, fortunately, certain amount of heat is given up to provide latent heat of vaporisation. In such type of dryers there can be a good control of heat and humidity provided it is designed correctly.
