PROCEDURE :

A schematic diagram of the experimental setup is given below:

It is a wind tunnel type tray dryer .

The main components are :

- Drying chamber

- Blower

- Heater

- Orifice in the tray duct

- A tray

- Balance

The air flow is controlled by a gate valve in the blower inlet and its flow rate is measured by a pre - calibrated orifice meter. The temperature is controlled by an energy regulator.Wet bulb and dry bulb thermometers are placed at the inlet and outlet of the drying chamber.

Experimental Procedure :

1. Load the pre - weighed tray with solid and place it over the balance in the drying chamber.

2. Record the weight of sand and tray.

3. Start the blower and fix the air flow rate and also its inlet temperature by adjusting the energy regulator.

4. When the desired conditions of temperature and air velocity are reached , remove the sample tray and put known amount of water in it to give a desired initial moisture content.

5. Keep the tray gently in the drying chamber and start the stop watch.Record the balance reading with time at about 3-5 min interval.

6. Drying is assumed to be complete when atleast 3 consecutive readings are unchanged.

7. The same steps are repeated for other runs at different operating conditions.

The animation below describes the process: