by dewi susanti
Autoclaves are mostly used in hospitals, tattoo shops, piercing shops and in dentistry, the medical equipments used in these facilities have to be sterilized against pathogens and bacteria.
Autoclave machines vary depending on size and functionality and also depending on the item to be sterilized. For an autoclave machine to be effective, it must have some dry steam inside it’s chamber.
This is achieved by first removing all the air from its chamber. This process is referred to as vacuum pumping. After all the air is removed from the chamber, the temperature and pressure within the vessel rises until the selected temperature is reached.
To create the required temperature inside the container, steam is injected through a pre-set steam source. This is achieved through various mechanisms for different types of autoclave machines.
Some employ heaters at the base to heat water till boiling and hence producing steam, others however have an input nozzle for steam from an external source such as a steam generator.
Despite anyone’s preferences, the direct steam method has proven to be the most effective method because it allows cycle times to be faster since steam is always readily available. The standard temperature for an autoclave machine is 121 degrees Celsius for a pressure of about 15psi and a period of about 15 minutes.
For instruments that might get corroded by the autoclave machine, dry heat is normally used. A disadvantage that dry heat has over steam sterilization is the fact that it requires a long exposure time since penetration is slow, also because of the high temperature required for dry heat, some objects can easily get destroyed.
There are many different types of autoclave machines but all of them can be categorized into three broad categories; Gravity displacement autoclaves, positive pressure displacement autoclaves and negative pressure displacement autoclaves.
•Gravity displacement autoclaves.
These are the most common and most basic types of autoclave machines. As their name suggests, this category of autoclaves employ the displacement of air and steam through a port located close to the bottom of the sterilization chamber.
•Positive pressure displacement autoclaves.
This type of autoclaves comprise of a separate steam generator that forces steam jets to displace air to enable sterilization to be performed at a higher temperature.
•Negative pressure displacement autoclaves.
This is however the most accurate and efficient type. Also known as a vacuum autoclave, it utilizes a vacuum pump to suck the air inside the sterilizing chamber. After all the air is removed from the chamber, pressurized steam gets injected inside the sterilization chamber similar to the positive pressure displacement autoclave. The problem with these types of autoclaves is that they are normally very large and as such very costly.
Autoclave machines are the most effective and efficient devices to be used for sterilization purposes, they are simple and very easy to use.
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