Have you given much thought to how Surgeons are able to use the same surgical tools many times without passing the germs from one person to the next person they do surgery on? Or maybe you wonder how nail salons keep from passing fungal infections between clients. You probably figured that it has something to do with cleaning the instruments that they use. Yet, you know that simply cleaning these items would not be enough to keep them from passing germs or infections. Something must be done in order to sterilize, or kill all living organisms on these tools.
The autoclave carries out that exact function of sterilizing materials. It is a machine that uses pressure and steam to reach and maintain a temperature that is too high for any microorganisms or their spores to live. Microorganisms are what most people commonly refer to as germs. These are the bacteria, viruses, fungi, parasites, etc. that are able to cause infections in our bodies. Spores are the environment-resistant form of the microorganisms. Even though they are able to withstand harsher conditions, they still can be killed if extreme conditions are maintained for an extended period of time
The basic parts of an autoclave include a reservoir for the water, a heating element, a drain and a vacuum-pressurized door.
The outside of the autoclave has indicators so the user can ensure the equipment is working properly. Indicators include a pressure gauge, a temperature indicator, a low water light, a timer, and an on/off switch, light or button. The outside door and latch are designed to withstand the high pressure created inside the autoclave to achieve sterilization. Inside the door is a compartment. Equipment that needs to be sterilized is placed inside this compartment on the shelf. Larger autoclaves may have multiple shelves.
The outside of the compartment has a liner, or jacket, with holes to allow the steam to enter the compartment. The steam comes from the water reservoir, which is filled with distilled water. Outside that jacket is a heating element that creates the steam. This is covered by another jacket or metal liner. A drain pipe and valve are located at the bottom of the unit to allow water and steam to escape when the sterilization process is complete.
The Basic Autoclave Parts
Autoclave parts are basically four in number, namely:
1. Water intake – this provides the water used to produce the steam that is used in sterilization process. Large models have their water intake connected to a continuous water supply whereas smaller models usually have a reservoir that is filled with water periodically.
2. The chamber – refers to the space that accommodates the load to be sterilized. This chamber contains wire racks that hold items to be sterilized so that steam can penetrate them. The chamber is accessible via an air-tight door which automatically closes and can only open when sterilization process is finished. This ensures safety for the operator and also perfect disinfection.
3. The control panel – allows for users’ customized settings. The control panel controls temperature, pressure and time for the autoclave process. Some loads will require higher temperatures than others. Other items will require more time inside the autoclave so as to achieve their maximum sterility. The user can vary these parameters straight from the control panel.
4. Air pump system – this system pumps out air from the chamber so as to create a vacuum which will then be filled with steam. It is important to remove the air so as to avoid any chemical reactions between the steam and the loads to be sterilized.
The chamber in which all the sterilization is done should be an air-free and air-tight zone. The air in the chamber should be removed either through vacuum pumping, steam pulsing and pumping, or upward displacement of air by steam.
Once the zone has been made a vacuum, air should be prevented from entering again during the cleansing process. Hence, the door is the most important of all the autoclave parts.
The door usually contains an insulation pad, which can wear and lose its air-tight properties with time. This pad gets thinner, folds in and loses its insulating properties. This then calls for a quick response to its replacement so as to keep the autoclave fully operational without faults.
It is easy to do it yourself without the help of a technician though it is recommended you call for assistance from autoclave technicians.
How its works
Autoclaves are pressure cookers, they are very similar to the ones that you see in the stores. If you have used, or are familiar with pressure cookers, then you know that foods cook a lot faster in a pressure cooker than they do in a regular pot or in the oven. This is due to the intense heat and pressure that is applied to the food. The same mechanism works against living microorganisms.
Once an autoclave is started, steam is pushed into the chamber that contains the items that are being sterilized. As the steam goes in, the pressure and temperature within the chamber is increased. Most autoclaves are set to increase steam pressure until a temperature of at least 121 degrees Celsius is reached (about 250 degrees Fahrenheit). This temperature and pressure will remain at this level for at least 15 minutes. This is a high enough temperature for a long enough period of time to kill any and all microorganisms and their spores.
The high temperatures cause the internal parts of the microorganisms to essentially cook. Once the internal parts cannot function in the microorganisms, they will die. The steam and pressure are released and brought down to normal room temperature and pressure after the 15 or more minutes of running. The items that were autoclaved will remain sterile until they are contaminated by new microorganisms.
An autoclave is a sterilizer instrument which is very essential in many applications such as hospitals, tattoo and body art studios, as well as in medical and research laboratories
1. Microbiology, Jacquelyn Black, Prentice Hall,1993 pg 334
2. “Chronological reference marks – Charles Chamberland (1851–1908)”. Pasteur Institute. Archived from the original on 19 December 2006. Retrieved 2007-01-19.
3. Hugo WB (July 1991). “A brief history of heat and chemical preservation and disinfection”. J. Appl. Bacteriol. 71 (1): 9–18. doi:10.1111/j.1365-2672.1991.tb04657.x. PMID 1894581.
4. “Online Etymology Dictionary”. Etymonline.com. Retrieved 2012-06-04.
5. “Sterilization Cycles”. Consolidated Machine Corporation. Retrieved 2009-06-30.
6. Seymour Stanton Block (2001). Disinfection, Sterilization, and Preservation. Lippincott Williams & Wilkins. ISBN 978-0-683-30740-5. Retrieved 19 January 2013.
7. R. B. Simpson (28 February 2002). Rubber Basics. iSmithers Rapra Publishing. p. 161. ISBN 978-1-85957-307-5. Retrieved 19 January 2013.
8. AS NZS 4815-2006 P33&P35
9. Health Technical Memorandum 01-05. Retrieved 24 September 2014. “These instruments are suitable for storage for up to 12 months in their original packaging as long as their packaging is intact. Practices will need to have systems in place to be able to demonstrate that the 12-month storage time is not being exceeded.”
By: Oluwaseun Adeogun; a Business Support Executive at Applied Analytical Systems Litd., 8, Atunwa Street, Ikeja, Lagos, Nigeria. Phone (234) 8037396888, email: [email protected] website www.aasnig.com