AUTOCLAVE

An autoclave is an apparatus which provides physical means for sterilization: killing bacteria and viruses, even spores in the material kept inside the vessel, by using steam under pressure.

The autoclave sterilizes materials by heating them to an upward temperature for a specific amount of time. Autoclave is also known as steam sterilizer, which is generally used in health care departments and industries for several reasons. Autoclave is more efficient in sterilization because it operates on moist heat sterilization.

A scientist named Chamberland in 1884 developed autoclave.



PARTS


An autoclave is a metallic vessel made of stainless steel or copper. It is a double walled cylinder in which one end is closed and another end is open. The open end is provided with a lid. The lid of an autoclave is equipped with pressure gauge, exhaust valve and safety valve. The closed end is provided with heating coil and a rusting plate. 


PROCEDURE
  • Water is filled below the level of resting plate. Current is passed and the water is allowed to boil.
  •  The lid is closed airtight. The water is boiled to produce steam which is released into the autoclave chamber. The air initially present in the chamber is forced out until the chamber is filled with saturated steam and the outlets are closed. 
  • Hot saturated steam continues to enter until the chamber reaches the desired temperature and pressure i.e. the temperature 1210 C at 15 lbs pressure for 15-30 mins. This temperature is sufficient to kill all microorganisms. 
  • At the temperature of 1210 C steam readily condenses on the surface of cooler objects and in doing so tremendous amount of heat energy are transferred from steam to the object. 
  • Saturated steam heats an object about 2500 times more efficiently than hot air at the same temperature.
  • Powders, water insoluble materials such as mineral oils should not be autoclaved because steam can't penetrate these materials.
  • Bacterial endospores will be killed only if they are kept at 1210 C for 30 mins.





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