What Is An Autoclave？

Introduction

High-pressure steam sterilizer is a device that uses saturated pressure steam to quickly and reliably sterilize items. It is suitable for medical, scientific research, agriculture and other units. It can sterilize medical equipment, dressings, glassware, solution culture medium, etc.

It is also suitable for steaming food equipment in plateau areas and enterprises and institutions to produce high-quality drinking water. It can also be used as a high-temperature steam source equipment. It is a commonly used sterilization method in microbiological experiments.

Classification of autoclaves

According to the style and volume size, high-pressure steam sterilizers can be divided into portable high-pressure steam sterilizers, vertical high-pressure steam sterilizers, horizontal high-pressure steam sterilizers, etc.

The volume of portable high-pressure steam sterilizers is usually 18L, 24L, and 30L.

The volume range of vertical high-pressure steam sterilizers is usually 30L-200L, which can be further divided into handwheel type, flip type, and intelligent type. The intelligent type is further divided into standard configuration type, steam internal exhaust type, and vacuum drying type. A printer can also be added according to customer requirements.

Horizontal high-pressure steam sterilizers are usually large horizontal high-pressure steam sterilizers.

Structure and principle of high-pressure sterilizers

High-pressure steam sterilizers consist of a sterilization chamber, a control system, an overpressure protection device, etc. High-temperature saturated water vapor can be used to denature the protein of microorganisms and cause the death of microorganisms within a certain period of time, thereby achieving the purpose of sterilizing moisture-resistant and heat-resistant items.

Since the steam cannot overflow in a closed steamer, the boiling point of water will continue to increase as the pressure continues to rise, and the temperature in the pot will also increase accordingly. The temperature in the pot can reach 121°C at a pressure of 0.1MPa. Various bacteria can be killed quickly at this steam temperature.

Operation steps of high-pressure sterilizer

1. First, take out the inner sterilization barrel, and then add an appropriate amount of water to the outer pot so that the water surface is level with the triangular shelf.

2. Put the sterilization barrel back and put in the items to be sterilized. Be careful not to fill it too crowded to avoid hindering the circulation of steam and affecting the sterilization effect.

3. Cover and insert the exhaust hose on the cover into the exhaust groove of the inner sterilization barrel. Then tighten the two opposite bolts in a symmetrical way at the same time to make the bolts uniformly tight and prevent air leakage.

4. Turn on the power to heat, and open the exhaust valve at the same time to boil the water to remove the cold air in the pot. After the cold air is completely exhausted, close the exhaust valve and let the temperature in the pot gradually rise with the increase of steam pressure. When the pressure in the pot rises to the required pressure, control the heat source and maintain the pressure for the required time.

5. After the required sterilization time is up, cut off the power or turn off the gas to let the temperature in the sterilization pot drop naturally. When the pressure on the pressure gauge drops to 0, open the exhaust valve, loosen the bolts, open the lid, and take out the sterilized items.

Precautions for high pressure sterilizer

1. Preliminary treatment of sterilized items

All medical equipment, sheets, clothing, etc. that have been in contact with pathogenic microorganisms should be disinfected with chemical disinfectants first, and then cleaned as usual. In particular, all kinds of items used in infectious wards must be strictly checked, and they must be strictly disinfected first, and then cleaned and disinfected. During routine cleaning, first soak and scrub with detergent solution to remove oil, blood and other dirt on the items, and then rinse with running water. Instruments and other items with joints, tooth grooves and gaps should be opened or disassembled as much as possible and thoroughly washed. After washing, the items should be wiped dry and packaged according to clinical needs to avoid re-contamination. The containers and transportation tools of the items before and after the contamination should be strictly distinguished to prevent cross infection.

2. The packaging and containers of sterilized items should be appropriate

The packaging uses white cotton double-layer wrapping cloth, and the new wrapping cloth should be washed and de-starched before use. The items are packaged with ropes, which should not be loose or scattered, but should not be too tight. When using containers for storage, choose containers that can block the invasion of external microorganisms and have good steam permeability, such as special syringe sterilization boxes, storage tanks for dressings, etc.

3. The sterilized items should be placed reasonably

The items in the sterilizer should not be overcrowded and should not exceed the capacity of the pot. Try to sterilize similar items in the same pot. If different types of items are placed together, the temperature and time required for sterilizing items that are difficult to reach should be used as the standard. When placing items, they should be staggered up and down, left and right, leaving gaps to allow steam to penetrate easily. Large disinfection packages should be placed upright on the upper layer, and small packages on the lower layer. When cloth and metal items are sterilized at the same time, the metal items should be placed on the lower layer so that the heat is basically the same for both, and to prevent the condensed water generated during the sterilization of metal items from wetting the package cloth.

4. Exhaust the air

When using a high-pressure steam sterilizer, the most important thing is to exhaust the air in the pot. If there is air in the pot, the pressure indicated by the air pressure needle is not the pressure generated by saturated steam. At the same pressure, the temperature of steam mixed with air is lower than the temperature generated by saturated steam. Therefore, the air in the pot must be completely exhausted so that the pot is full of water vapor, so that sterilization can be thorough. The common method is: close the vent valve, after power on, when the pressure rises to 0.05MPa, open the vent valve to release the air, and close the vent valve after the pressure gauge pointer returns to zero. After closing the valve and then turning on the power, when the pressure gauge rises to 0.1MPa, start timing and maintain the pressure for the specified time.

5. Reasonable calculation of sterilization time

Sterilization time includes: penetration time, which is the time required from the sterilization temperature in the pot to the most difficult part of the pot reaching this temperature; maintenance time, which is the time required to kill microorganisms, generally expressed as the time required to kill thermophilic bacillus spores; safety time, which is the additional time required to ensure sterilization, which is generally half of the thermal death time, and its length depends on the sterilized items. For the sterilization of metal equipment that is easy to conduct heat, safety time is not required. During the sterilization time, pay attention to observe the pressure gauge to maintain the specified pressure until the sterilization time. During the sterilization process, if there is a drop in pressure or temperature, the temperature and pressure should be raised again and the timing should be restarted.

6. Opening the lid

When the sterilization time is reached, the power can be cut off. When the pressure drops to 0.05MPa, the steam can be slowly released. Be careful not to reduce the pressure too quickly, which may cause intense decompression boiling and overflow the liquid in the container. The lid can be opened only when the pressure drops to zero. Take out the culture medium and place it on the platform for condensation. Do not release the air for a long time, otherwise it will easily cause the composition of the culture medium to change and make it impossible to make the slant culture medium. If the boiler is negatively pressurized and the lid cannot be opened due to long-term non-release, the vent valve can be opened to let air in. The lid can be opened after the internal and external pressures are balanced.

7. Post-sterilization operation

The indicator is required to be checked after the sterilized items are dried, and they can be taken out of the pot when the sterilization requirements are met. When taking sterile items, strict aseptic operation must be performed. The lid of the opened items must be closed first, and the vent holes of the storage tank must be closed. At the same time, they should be placed in categories and issued and taken in sequence.