Hot air oven

• Introduction
• Principle
• Component
• Procedure for use
• Care and maintenance
• Uses
• Specification

Introduction:-

Hot air ovens use extremely high temperatures over several hours to destroy microorganisms and bacterial spores.

Principle:-

When electricity is passed through the heating coils, electrical energy is converted to heat energy. The temperature is controlled by a thermostat.

Component:-

1. Double walled heavy gauge aluminium chamber.
2. Continuous heat elements externally wound on all sizes of the working chamber (these enable efficient heat transfer by conduction and radiation).
3. Thermal insulation by thick glass-wool between the working chamber and the outer mild steel casting.
4. Thermostat
5. Adjustable ventilator
6. Pilot lamp
7. Temperature controller
8. Perforated metal shelves
9. Thermometer (Temperature range: 40°C to 300°C).

Procedure for use :-

1. Place dry articles on the shelves. (In the case of glassware, the excess water should be drained completely).
2. Close doors firmly.
3. Put on the main switch.
4. Control temperature by adjusting the control knob.
5. Keep it on for the required time period.
6. Put off the main switch.
7. Remove the articles.

Care and maintenance:-

1 Do not forget to put off the main switch when the heating period is over.
2 Clean the hot air oven after use.

Uses:-

Hot air oven is mainly used for the following various purposes.
1. Dry sterilization
2. Preparation of anticoagulated bulbs
3. Drying of glassware .
4. Heating of chemicals used for the preparation of Primary standard.

Specification:-

Following are the important specifications preferred for the selection of A) Incubator B) Hot air oven & C) Water- bath
1. Inner dimensions
2. Outer dimension
3. Number of shelves ( in the case of A and B)
4.Temperature Range
5.Efficiency of thermostats giving accuracy +-1⁰ c