Laboratory Autoclave. An autoclave is a thick-walled metal pressure vessel with a hermetic seal that allows high-pressure work to be carried out for industrial reaction, cooking or steam sterilization. Its construction must be such that it resists the pressure and temperature developed inside it. The high pressure allows the water to reach temperatures above 100 ° C. The joint action of temperature and steam produces the coagulation of the proteins of the microorganisms, including those essential for their life and reproduction, a fact that leads to their destruction.
The word autoclave is not limited to equipment that works with steam since the equipment used to sterilize with ethylene oxide is named the same way. The autoclave was invented by Charles Chamberland in 1879 .
Summary
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- 1 Objective
- 2 Types of Autoclave
- 3 Composition
- 4 Stages of Autoclave Operation
- 5 Considerations
- 6 Sources
objective
The autoclave inactivates all viruses and bacteria , although it has been known that some microorganisms can withstand autoclave temperatures. Autoclaves are used in mainly sterilization applications and in the chemical industry . • It is responsible for eliminating all microbial life including spores in materials, surgical equipment, textiles and glass except plastic . • Provide patient safety. • Absence of toxic residue in sterilized material and equipment.
For the effectiveness of steam sterilization (Autoclave) it must have three parameters that must be controlled, they are:
- Temperature : Temperature at which the chamber is maintained during the sterilization phase.
- Pressure : The steam will be saturated and free of impurities using treated water . The
Steam purity, saturation, and steam availability are important process variables, depending on the quality of the steam whether or not sterilization is effective. These impurities can oxidize the instruments.
- Time : Exposure time of the product or the camera to the temperature of
sterilization. It is the duration of the sterilization phase.
Autoclave Types
- By gravity: The air is removed by gravity, when the steam enters the chamber, the cold air that is in it tends to exit through the duct that is at the bottom of the chamber. This process is very slow and favors the permanence of residual air in the chamber.
- Prevalence: They have a vacuum pump that quickly removes all the air from the chamber, so that the steam is introduced at a higher speed inside the chamber, improving the efficiency of the autoclave by eliminating air pockets and increasing the speed of the process . It is a much more efficient system than others.
Composition
An autoclave is made up of these parts: 6 • Safety valve: Its function is to prevent steam or water from escaping before the sterilization process ends. • Drain valve : which is where the steam produced by the water heated in the heater comes out, when the ideal temperature for sterilization is reached. • Resistance: which is used to heat the water that will go into the kettle, which will be worked at certain temperatures depending on the degree of sterilization that you want to reach. • Tray: where the material to be sterilized will be placed. • Calderin: where it was treated at the necessary temperatures that must be produced to eliminate bacteriaand the microorganisms that you want to eliminate. • Lid: which is nothing more than the closing of the machinery.
Autoclave Operation Stages
- Commissioning: The doors are hermetically closed so that the chamber is sealed.
- Air Expulsion : In this phase the air contained in the chamber will be eliminated and the subsequent elimination of air inside the packages and containers will be favored. For this, steam is injected into the chamber and the vacuum system is activated.
- Preparation: For the extraction of air from the products and the chamber, a series of phases (up to four) of steam injection (chamber to chamber) are carried out, followed by phases of vacuum (pre-vacuum), using the vacuum system, to completely remove the remaining air.
- Heating: Steam is introduced into the chamber and inside the containers, until the sterilization temperature and pressure are reached.
- Sterilization: The temperature and pressure in the chamber are kept constant during the corresponding sterilization time.
- Devaluation: Vapor from the chamber is removed by the vacuum system and a drop in pressure occurs.
- Drying: A final, deep and lasting vacuum begins. Steam is kept in the chamber to keep the chamber warm and to help dry the product to avoid all kinds of bacterial recontamination during transport and storage.
- Equalization: Inlet of atmospheric air to the chamber, through a sterile air filter, to compensate the pressure of the chamber (which was in depression) with the atmospheric one. The steam used condenses and turns into water, transporting it to a tank.
- Completion of the Process: The doors are released so that they can be opened.
Considerations
Autoclaves use high pressure, high temperature steam for sterilization. The risks are potential and therefore it is necessary to follow certain considerations. Possible Hazards: • Skin burns can be caused by handling the walls and door of the autoclave chamber. • The residual steam that leaves the autoclave and the materials at the end of the cycle of use. • Hand and arm injuries when closing the door. • Bodily injury if there is an explosion.
To ensure the health and safety of personnel who use the autoclave, it is important to: • Train personnel regarding the proper use of the autoclave. • The name of the person responsible for the autoclave must be placed near the autoclave. • It is the supervisor’s responsibility to ensure that employees are trained before operating any autoclave unit. • The procedural and instructional documents provided by the manufacturer must be followed. • Personal protective clothing and equipment must be worn when loading and unloading the autoclave. • Autoclaves must be inspected at least once a year. • The spore strips can be used to validate the efficiency of the autoclave operation.
The equipment to protect against burns includes: • Thermal insulation gloves that provide complete coverage of the hands and forearm. •Lab coat. • Eye protection. • Footwear with closed feet.
It is very important for sterilization that the steam is: • Clean: That is, a steam formed from clean water, that is, filtered water and free of contaminating substances such as cadmium , magnesium , lead or chlorine, among others. • Pure: This means that the presence of water in liquid form is very low, this is considered when it is less than 3%. For sterilization to be effective: • The steam must be in direct contact with the material to be sterilized (so the load of the elements is very important). • Create the effective vacuum in order to displace all the air initially present in the autoclave and replace it with steam.
