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2 English ReferenceDry Heat Sterilization
Hotair Sterilization
Dry heat sterilization is a physical sterilization method that utilizes flame, dry heat or infrared oven. Dry heat sterilization is the use of flame, dry heat air electric heat or infrared oven high heat baking sterilization method, belongs to the physical sterilization method. Including flame sterilization, dry hot air sterilization and high-speed hot air sterilization. In addition to a very small number of drugs using dry hot air sterilization, mostly used in glass, ceramics and other appliances, as well as should not be sterilized by pressure steam gelatin sponge, petroleum jelly, grease, wax, paraffin and a variety of powders and other items of sterilization. Intolerance of high heat items, such as cotton fabrics, plastics, synthetic fibers and rubber products, etc., can not be sterilized with this method.
3 dry heat sterilization method includedDry heat sterilization requires a higher temperature and longer time than moist heat sterilization.
(1) dry baking: the use of dry oven, heating 160 ~ 180 ℃ for 2 hours, can kill all microorganisms, including germs. Mainly used for glassware, porcelain and other sterilization.
(2) cauterization and incineration: cauterization is a direct flame to kill microorganisms, applicable to microbiology laboratories, inoculation needles and other metal equipment is not afraid of heat sterilization. Incineration is a thorough sterilization method, but is limited to the treatment of discarded contaminated items, such as useless clothing, paper, garbage, etc.. Incineration should be carried out in a special incinerator.
(3) infrared: infrared radiation is a 0.77 ~ 1000 micron wavelength electromagnetic waves, has a good thermal effect, especially 1 ~ 10 micron wavelength of the strongest thermal effect. Also considered a dry heat sterilization. Infrared light generated by infrared bulbs, do not need air conduction, so the heating rate is fast, but the thermal effect can only be generated on the surface of the irradiation, so it can not make an object before and after the left and right uniform heating. Infrared sterilization and dry heat similar to the use of infrared oven sterilization of the required temperature and time is the same as dry baking. Mostly used for sterilization of medical equipment.
People exposed to infrared radiation for a long time will feel fatigue and headache; long-term exposure will cause intraocular damage. Therefore, workers should at least wear protective glasses against infrared damage.
(4) microwave: microwave is a wavelength of 1 millimeter to 1 meter or so of electromagnetic waves, high frequency, can penetrate glass, plastic film and ceramics and other substances, but can not penetrate the metal surface. Microwave can make the medium messy polar molecules in the microwave field under the action of the frequency of the wave back and forth movement, mutual collision and friction and generate heat, the temperature of the medium can be increased, and thus at lower temperatures can play a role in sterilization. It is generally believed that its sterilization mechanism in addition to the thermal effect, there are electromagnetic **** vibration effect, the role of field effect. Sterilization in the commonly used microwave 2450MHZ and 915MHZ two kinds. Microwave irradiation is used for food processing. In the hospital can be used for laboratory supplies, non-metallic instruments, sterile sick room food utensils, medicine cups and other supplies disinfection.
Microwave long-term irradiation can cause eye clouding, testicular damage and neurological disorders and other systemic reactions, so the door must be closed before the start of the operation.
4 dry heat sterilization method of operation1. Sterilized items should be contained in appropriate containers, placed in the oven, closed and heated to the specified time (the following table). Gelatin sponge heating temperature should be lower, can be heated to 120 ℃ lasted to 180 ~ 240min.
Various temperatures of dry heat sterilization required action time
Temperature (℃) action time (min) 160 120 ~ 150 170 60 ~ 90 180 30 ~ 40 ? Note: Start calculating the action time after reaching this temperature.