Autoclave works like a pressure cooker or microwave oven. The difference from the previous instruments is the heat of autoclave. This instrument uses extreme heat to kill germs and other microorganisms. The extra steam pressure in autoclave means that the boiling point is 20 Celsius hotter than the normal boiling point. It can effectively kill hazardous germs and microorganisms.
This instrument is commonly used in hospitals for medical instruments sterilization. It is usually in form of steel vessel that produces steam to sterilize many things. Aside of being used as a medical instrument, it can be used as a scientific instrument, industrial instrument, and many more. Commonly the chamber is cylindrical because it is a lot better in handle extreme pressure. The use of box chamber is uncommon because the edges are very easy to break. The edges are the weak points that cannot stand extreme pressure.
The air is removed once the chamber is sealed. It can be done by a vacuum pump or by pumping in the steam so the air is forced out by the steam. When the temperature of 121-140C is reached, thermostat starts the timer. The steam is pumped for about 3 minutes for minimum and 15 to 20 minutes for maximum. There is no exact sterilizing time because it always depends on the things that we are going to sterilize. The contamination levels may affect too. If you do not pay attention to these factors, the items that you sterilize are not sterile enough.