The autoclave is a metal wall sterilizer / device that is resistant to high pressure. The autoclaves, which can be of different shapes (square, rectangular), have a faucet to put water inside the boiler, a faucet, a manometer and a safety valve that allow air and steam to escape. It also has a tap that allows steam to escape. Autoclaves work with electrical energy. Steam is produced in the boiler. Air passes through the open valve until the boiler is filled with saturated steam. It is defined as small or large depending on the size of the material that can be placed in autoclaves.

Small autoclaves; They are autoclaves that can not fit in a box of 30x30x60 cm and are under 60 liters. Three different cycles can be made in these sterilizers:

o N-type (Non-wrapped) sterilization cycle: Works on the principle of gravity. It can be used only for the sterilization of unpackaged and lumen-free materials. It is not preferred as a routine sterilization program.
S Type (Specified) sterilization cycle: It works with pre-vacuum. Sterilizers, which are generally used in dentistry, are of this type.
o Type B (Big) sterilization cycle: Fractionated pre-vacuum works. It can be used for sterilization of all kinds of medical devices, with or without lumens, with or without packaging.

Large autoclaves; are autoclaves with a boiler that a box of at least 30x30x60 cm can enter. Depending on the working principle, it is defined as gravity, vacuum, pre-vacuum or fractional pre-vacuum steam autoclaves.


Gravity Autoclaves
The steam is replaced by air entering the sterilizer. This sterilizer is mostly used for the sterilization of liquids. Autoclaves used in microbiology laboratories, equipment and medium sterilization are of this type. For liquid sterilization in gravity sterilizers:
 1. Temperature resistant borosilicate glass bottles should be preferred.
 2. The bottles should be ventilated or the caps should not be closed too tightly.
 3. Only liquid program should be used.
 4. The time of equilibration between the liquid to be sterilized and the internal temperature of the autoclave is directly proportional to the total amount of liquid.
 5. The sterilization time should begin after the temperature has stabilized. For this, a temperature sensor must be placed in the largest liquid container in the cycle, and the sterilization period must be started after the temperature in this container reaches 121 ° C. In autoclaves without temperature sensors, attention should be paid to the amount of liquid and the times in the table.
 6. There are systems that use air or water for cooling after sterilization. Cooling should be done very slowly. In autoclaves that do not have a cooling system, liquids must be allowed to cool on their own before opening the lid. Otherwise, the bottles may burst or break.
Pre Vacuum Autoclaves
After preheating, the air in the sterilizer is evacuated by vacuum and then the steam fills the sterilizer in series waves. The autoclave is loaded according to the principles stated below.
* Large packages are placed on the bottom shelf and small packages on the top shelf.
* Containers can be loaded on the same side.
* Materials packed with non-woven fabric can be loaded on the same side.
* For loading, racks that will allow the steam to circulate between the packages should be used.
* It should never be loaded on a container with non-woven fabric sets or a container on a non-woven fabric-packed set, as this will result in a wet package.
* The bundles should be in a vertical / inclined position, the tool trays should be loaded horizontally on the bottom shelf.
* There should be a gap between the packs and a 5-10 cm gap between the wall of the sterilizer.
* In materials packed with sterilization bags, close to twice the package during sterilization.
Considering that it will expand, loading should be made and these packages should never be compressed.
* Maximum 70% of the boiler volume must be filled.
* Patient drape sets and hollow bowls should be placed side by side facing slightly.
The relationship between pressurized saturated steam and heat-time in sterilization is as follows:

* 5 minutes at 134 ° C. (in pre-vacuum autoclaves)
* 15 minutes at 121 ° C. (in pre-vacuum autoclaves)
* 30 minutes at 121 ° C. (in vacuum-free autoclaves)
* 20 minutes at 126 ° C. (in vacuum-free autoclaves)
* 15 minutes at 134 ° C. (in vacuum-free autoclaves)

Operation of Autoclave
 The packaged tools are properly sterilized by autoclave loading. This is done as follows:
* Physical control of the chart recorder, pressure, humidity control etc. indicators of the autoclave device is done.
* Required control tests are placed in the device chamber in accordance with the technique.
* The device cover is closed.
* Device operation program is entered.
* The operation of the device is followed.
* At the end of the procedure, the load is discharged from the cover that opens to the sterilized area of the autoclave.