Principle on Which Autoclave Works
Autoclaves function on the principles of physics and thermodynamics to effectively kill microorganisms on instruments. Autoclaves use moist heat (steam) to apply heat and pressure to achieve sterilization by applying these principles and by doing so; autoclaves can destroy the most resistant microorganisms like bacterial spores that may otherwise survive under normal environmental conditions. Microorganisms that can be effectively eliminated include bacteria, viruses, fungi and fungal spores.
Procurement professionals, distributors and dealers can utilize this article to gain better knowledge of the autoclave sterilization process and some aspects of selection before purchasing these life-saving machines.
Autoclaves rely on a few fundamental principles to operate in a sterilization cycle. Autoclaves use water to generate steam, a process where the temperature and pressure are closely related. The pressure applied inside the autoclave chamber and the temperature at which the heat is applied are essential for the efficient operation of the sterilization process. The autoclave sterilization process also employs specific heat transfer methods and the sterilization process comprises various essential phases, which are key for effective sterilization. Monitoring and controlling these phases is done by control panels and systems that come with most autoclaves. This article will explain each of these principles that an autoclave relies on.
Principles on Which Autoclaves Work
はじめに
Sterilization of contaminated instruments or materials in healthcare, laboratory and other research is often done using an autoclave.
Autoclaves work on the principles of steam and the scientific laws associated with these states of matter. The understanding of the application of this steam in terms of pressure and temperature needed for sterilization is very vital. In this article, we will be looking at the principles behind autoclave function and how the autoclave sterilization process works.
Autoclaves are considered the most effective sterilization method in healthcare, the sterilization process occurs through the use of hot, pressurized air or steam. The sterilization is effective on all types of microorganisms, such as viruses, bacteria, spores and fungi. There are three stages to the autoclave sterilization cycle.
Physics plays a crucial role in the sterilization process by controlling the functioning of the autoclave machine. Factors such as changes in physical state of materials in the autoclave chamber, heat transfer, pressure and temperature are all critical to the functioning of the machine. Autoclaves use the changes in physical states and heat transfer principles to achieve the right conditions for a successful sterilization.
Sterilization occurs in the autoclave chamber where the steam achieves a controlled pressure that is not easily exceeded and therefore, for sterilization to occur, heat and pressure should be at a certain point.
The phases of the autoclave sterilization process
Autoclaves operate by going through several phases which are essential for the whole sterilization process to be successful. The phases in an autoclave sterilization process include the pre-heating phase, sterilization phase and the cooling and drying phase. Pre-heating is done as the chamber is heated up to produce steam that will be used for the sterilization phase. The sterilization phase is the phase where sterilization is done. The last phase of autoclaving is the cooling and drying process, where the materials inside the autoclave are vented, and the moisture is removed.
Physics behind the autoclave process
Physics and physical properties of materials like air and water play an important role in autoclaving, which is the basis of understanding the functionality and use of autoclaves.
Autoclaves work according to the laws of physics and in the following ways;
- Changes in physical states: This change occurs as steam at a specific temperature with pressure that is not easily exceeded. Sterilization occurs in the autoclave chamber during this phase.
- Heat transfer: Temperature inside the autoclave chamber is increased by heat transfer, which is in the process of sterilization.
Physical laws
Autoclaves function based on the following principles that are essential for autoclave sterilization;
- Ideal gas law: Pressure and temperature are highly proportional when volume is not considered. This law states that the mass of gas contained by a certain volume is directly proportional to its temperature and pressure.
- Boyle¡¯s law: This states that the pressure and volume of gas are inversely proportional when temperature is not considered. This law can be applied in sterilization through autoclaving to sterilize because pressure is directly affected when temperature is high.
Mechanism of Sterilization
The autoclave process also involves various other principles and mechanisms by which sterilization is done and this includes;
- Principle of moist heat sterilization: This is where wet steam is used to transfer high heat through convection, conduction or both to the medium which has a high temperature of saturated steam. Microorganisms are inactivated by dry heat through oxidation at a high temperature.
- Sterilization by high temperature: Microorganisms are inactivated by heat, which inactivates enzymes and causes denaturation. The growth of bacteria can be achieved at different temperature ranges, which inactivates bacteria at higher temperatures
- Pressure control: In an autoclave, the sterilization process is based on the control of temperature and pressure. Temperature and pressure should be at a certain point, and both are directly proportional.
Physics of steam
Steam, which is generated using autoclaves and is essential for the sterilization process of autoclaves, has the following physics;
- Temperature: The phase change of steam requires a certain temperature. The steam point temperature is higher than 100 degrees Celsius. Temperatures are also used to identify and classify organisms. Different microorganisms have different thermal death points and thermal death times and can be killed at a particular temperature in a stipulated time
- Volume: In the steam-generating vessel used to produce steam, the volume is inversely related to pressure. Pressure should not exceed that at the top of the standard atmosphere.
Pressure, temperature, humidity
Autoclaves can be used to achieve different levels of pressure and temperature to meet different needs and therefore the following is essential for the application of autoclaves;
- Heat and pressure: For sterilization to be effective with an autoclave machine, there is a requirement of heat and pressure. The heat can be in the form of steam.
- Controlled temperature: The temperature to be reached should be at a particular level so that a specific microorganism can be killed.
Microorganisms¡¯ sensitivity to moisture
Microorganisms¡¯ sensitivity to humidity is how humidity at a certain level can increase or decrease the likelihood of microorganisms¡¯ destruction in the application of autoclaves;
- Steam: Sterilization using dry heat can be achieved using steam, and sterilization is achieved with absolute humidity.
Factors to Consider When Selecting the Best Autoclave
There are factors that are considered by procurement professionals, distributors and dealers when selecting the best autoclave and these include;
- Type of material: the material type, which is to be sterilized is considered, because;
- If autoclaving is required, an autoclave will be considered and purchased.
- Heat-sensitive items: If the items are heat-sensitive, then alternative forms of sterilization are considered. The material should be autoclavable.
- Sterilization volume: It is also considered how many materials have to be sterilized on daily basis and;
- High requirement: an autoclave with a capacity to match the needs is selected when the requirement is high.
- If the volume is low, a small autoclave is sufficient.
- Standards for regulatory compliance: Compliance with regulatory bodies standards and requirements such as:
- Sterilization standards in Healthcare should be met by selecting an autoclave.
- Standards for validation.
- Local Health Authority standards
- Operational ease: Procurement professionals, distributors and dealers consider ease of operation and these considerations include:
- Controls and indication: If the autoclave is easy to operate by someone with the knowledge to operate.
- Maintenance: They also consider if the machine requires maintenance and the level of maintenance complexity.
- Costs: There are also considerations to be made for costs and these may include:
- The capital cost of the autoclave.
- Operating costs such as electricity and maintenance.
- The accessories for operation.
- The reputation of the manufacturer and support: Considerations are made for;
- The brand reputation through feedback from previous customers.
- Warranties: This is what is offered by different brands
- Support: Support from the manufacturers is also an aspect to be considered.
Advantages of Using an Autoclave
Autoclaves are applied in the sterilization process because of the following advantages;
- High efficacy: Autoclaves can be used on a wide range of microorganisms.
- Rapid Sterilization Cycles: Cycles last only a few minutes, which means that the entire process may take about 15 to 30 minutes
- Environmentally friendly: Autoclaves do not produce toxic residues.
- Versatile: Autoclaves can be used on different media
Best Practices for Use of Autoclaves
Best practices include pre-cleaning of instruments before sterilization by autoclaving to be used effectively. Autoclaves are filled with instruments without overcrowding and where the temperature is stable. Autoclaves can be applied with the following practices;
- Pre-Cleaning of Instruments
- Proper loading
- Regular maintenance and calibration
- Correct post-sterilization handling
結論
Autoclaves use the application of thermodynamics and physics principles to function in their sterilization process. Physics, steam and its principles play a crucial role in autoclaves. The three laws that are involved in the autoclave process include the ideal gas law, Boyle¡¯s law and the combined gas law. The sterilization process of autoclaves is achieved through several essential phases. Autoclaves are considered to be one of the most effective methods of sterilization because of its advantages, which are also considered for the application of this method of sterilization. For this method of sterilization to be used effectively, some practices are used, which are also considered for their application.
よくあるご質問
- What is the main principle of autoclave operation?
Ans. The main principle of autoclave operation is to use high-pressure steam that is moist and hot to combine the heat and pressure in the application of autoclaves.
- How does steam generation work in an autoclave?
Ans. In autoclaves, steam generation involves heating water in a sealed chamber to produce saturated steam, which will in turn raise temperature and pressure in the chamber.
- Why is the pressure-temperature relationship important in autoclaves?
Ans. The pressure-temperature relationship is important in autoclaves because increasing pressure will in turn increase the boiling point of water. As a result, temperature achieved for sterilization will be increased, and this is important for the destruction of resistant microorganisms.
- What are the phases of the sterilization cycle in an autoclave?
Ans. The phases of the sterilization cycle in an autoclave include the pre-heating phase, sterilization phase and the cooling and drying phase. Each of these is important for effective sterilization
- How can I ensure effective sterilization with an autoclave?
Ans. The best practice for the effective application of autoclaves includes the pre-cleaning of the instruments to be sterilized. This should be rinsed to remove residual blood or other substances and washed before loading for sterilization. The autoclave must be loaded without overcrowding to allow for free circulation of steam or gas. The performance of the autoclave can also be monitored regularly to ensure it is functioning correctly.