Operation specifications and precautions for autoclave

Autoclaves, also known as autoclaves, are important equipment often used in experiments. As special equipment with high temperature and high pressure, improper use may cause serious safety accidents. This paper comprehensively introduces the working principle and functions, safety hazards and standardized use methods of autoclave.

The autoclave is mainly composed of a sealable barrel body, pressure gauge, exhaust valve, safety valve and heating wire. It uses pressurized saturated steam to reach a temperature higher than boiling water. High-temperature steam is used to eliminate and kill microorganisms on high-temperature resistant items such as culture medium, metal instruments, and filter residue glass to ensure sterile conditions for the experiment.

In daily experiments, the sterilization conditions of the autoclave are usually that the temperature reaches 121.3 ° C, the pressure is maintained at 0.1MPa (103.4kPa or 1.05kg/cm²), and the time is maintained for 15 to 30 minutes. These conditions ensure that all microorganisms, including spores, are killed. They are a rapid and effective sterilization method and one of the most commonly used sterilization methods in the laboratory.

Usage specifications and precautions

At present, the autoclaves on the market are roughly divided into two types, semi-automatic and fully automatic. The semi-automatic autoclave requires manual operation of the programmable control system and the pressure relief system, which requires manual monitoring of the entire sterilization process so that adjustments can be made in a timely manner. The fully automatic autoclave can automatically complete the entire sterilization process. It only needs to set the processing mode and the operation is relatively simple.

1. Fully automatic autoclave

1) Preparations:

Equipment inspection: When using special equipment, attention should be paid to whether the sterilization pot passes the inspection, whether the safety valve is within the verification validity period, and whether the pressure gauge passes the inspection.

Check the water level: Before use, check the water level line of the external kettle. It is advisable to keep it lower between the highest line and the lowest line to prevent overheated water and steam from overflowing during the sterilization process, causing danger. Before use, inject proper amount of sterilization water (water injection amount shall be selected according to the requirements of different models of sterilization pot), RO water or single distilled water shall be used to prevent accumulated scale in sterilization pot.

Preparation for pot loading: Put the items to be sterilized into the basket, pay attention to the items not exceeding two-thirds of the basket volume, and keep a certain gap between the items to facilitate steam penetration.

Liquid sterilization preparation: The liquid should be filled in a hard heat-resistant glass bottle, the volume should not exceed three-quarters, and the bottle cap should be loosened to ensure the pressure balance inside and outside the bottle to prevent explosion.

2) Operation steps:

Close and lock the high-pressure pot lid: Gently press the pot lid, pull the handle to the locked position, and confirm that the sterilization pot is sealed and closed.

Select program and set parameters: Select the corresponding program according to different needs of sterilizers.

Start sterilization: Press the START button, the work indicator light will light up to indicate the start of sterilization operation, and the control panel will display the remaining sterilization time. Do not open the lid during use or when the pressure and temperature in the pot are too high. Emergency measures shall be taken in a timely manner for abnormal problems in operation and reported.

3) End of sterilization:

After the sterilization is completed, the machine will automatically sound a prompt. Only when the pressure in the sterilization pot is 0 and the temperature is lower than the safe temperature (80℃) can the lid of the sterilization pot be opened to prevent high-temperature steam burns.

After completing the sterilization work of the day, turn off the power switch and drain the water from the sterilization chamber.

2. Semi-automatic autoclave

1) Preparations:

The same as the fully automatic preparation work precautions.

2) Operation steps:

Close and lock the high-pressure lid: Hold the handle of the high-pressure lid with both hands and tighten it clockwise.

Close the exhaust valve: Turn the EXHAUST handle clockwise until it stops, and further tighten it to ensure safety.

Setting parameters: Manually set the required sterilization temperature and sterilization time. Correctly understand the corresponding relationship between pressure and temperature, and pay attention to the constancy of pressure and temperature during sterilizer operation.

Start the sterilization procedure: the entire sterilization process needs to be manually monitored to ensure normal operation of the equipment and deal with any abnormalities in a timely manner. Preheat before sterilization and remove cold air. Pay attention to observing the temperature under saturated steam pressure during sterilization to prevent overheating.

3) End of sterilization:

After sterilization is completed, the lid of the sterilization pot can be opened only after the pressure in the sterilization pot is 0 and the temperature is lower than the safe temperature (80℃) to prevent high-temperature steam burns.

If deflation and pressure reduction operations are needed, the bleeder valve should be gradually opened from small to large to ensure slow and stable release of gas and avoid opening the valve to the maximum position at one time. At the same time, it is important to keep in mind that steam cannot be released immediately after the sterilization process is over. You must wait until the pointer of the pressure gauge returns to a safe area before you can safely discharge the remaining gas.

After completing the sterilization work of the day, turn off the power switch and drain the water from the sterilization chamber.