Test procedure for testing the disinfection performance of ultraviolet sterilizers by bacterial aerosol chamber
Ultraviolet sterilizer refers to the equipment that uses ultraviolet mercury lamp as the light source and uses the 253.7nm ultraviolet rays radiated by the mercury vapor in the lamp tube as the main spectral line to sterilize drinking water. Its disinfection performance can be tested with a bacterial aerosol chamber. Let's learn how to do the disinfection test.
1. The installation of the UV air sterilizer to be tested cannot be opened until the end of the test.
2. Setting of test environment conditions: Turn on the temperature and humidity adjustment device, and adjust the temperature and relative humidity of the two bacterial aerosol chambers to the temperature (20°C~25°C) and relative humidity (50%~70%) required by the test.
3. Aerosol spray contamination: In the bacterial aerosol chambers of the control group and the test group, respectively, spray contamination according to the set pressure, gas flow rate and spray time of different aerosol sprayers. Stir with a fan (stirrer) while spraying the contamination. After spraying and contamination, continue stirring for 5 min and stand still for 5 min.
4. Sampling before disinfection: After spraying and contamination for 5 minutes, the bacterial aerosol chambers of the control group and the experimental group were sampled before disinfection respectively. It was used as a positive control (ie, the amount of infected bacteria) before the start of the experiment in the control group and before the disinfection treatment in the experimental group. The number of positive control bacteria in the aerosol indoor air should reach 5×10^4 CFU/m~5×10^5 CFU/m (the number of positive control bacteria in the control group at the last time of the disinfection test should not be less than 5×10^4 CFU/m
5. Disinfection treatment: Start the operation according to the instructions of the UV air sterilizer to be tested.
6. Sampling after disinfection: the ultraviolet air sterilizer is used for the first predetermined time (0.5 times the time specified in the product manual), and the bacterial aerosol chambers of the test group and the control group are sampled at the same time; Continue to act until the second predetermined disinfection time (the time specified in the product manual), and sample the bacterial aerosol chambers of the test group and the control group at the same time again.
7. Sampling requirements: Fix the six-stage sieve air impact sampler on the sampling vehicle, and make it located in the center of the bacterial aerosol chambers 1.0 m from the ground, the sampling flow is 28.3 L/min, and the sampling time is determined according to the prediction test. (Generally, the control group and the experimental group were sampled for 5 s to 10 s before the disinfection treatment, and the experimental group was taken after disinfection according to the disinfection effect).
8. Cultivation and result observation: after sampling, take out the plate aseptically, place it in a 36 ℃±1 ℃ incubator for 48 hours, and count the viable bacteria. After sampling the test group and the positive control group, the same batch of unused medium was cultured with the above two samples at the same time as a negative control. If there is bacterial growth in the negative control group, it means that the medium used is contaminated and the test is invalid.
9. Disinfection of the bacterial aerosol chambers: After the whole test is completed, after the final disinfection of the surface of the aerosol chamber and the bacteria remaining in the air, turn on the ventilator, filter and sterilize the air, and remove the polluted air remaining in the aerosol chamber.
The above is the disinfection test of the ultraviolet sterilizer in the bacterial aerosol chamber. If you have any doubts about this test, you can visit the official website of "Environmental Instrument" to learn about the relevant test methods.
