| Ultraviolet disinfection technology has the advantages such as high disinfection efficiency,no by-products,and disinfection effect on chlorine-resistant Giardia and Cryptosporidium.It is currently widely used in the field of water disinfection.The accurate measurement of UV output of an UV lamp is very important in the design,operation and optimization of UV disinfection reactors.Since temperature has appreciable influence on the UV output of a lamp,the method recommended by the International Ultraviolet Association（IUVA）to measure the UV output of a lamp operated in open air is not suitable for the measurement of an underwater lamp.This work has developed a measurement system for the UV output of the UV lamp,which can not only measure the UV output in the air,but also accurately measure the underwater output.The stability of the KI/KIO3 chemical actinometer,the mathematical model of collimated beam apparatus（CBA）,and the measurement method of UV output of an underwater lamp were studied in this thesis.The main contents are as follows:（1）The influence factors on the stability of the KI/KIO3 chemical actinometer were studied.The influence of room light,time,temperature,solution preparation method,and stirring factors on measurement accuracy were investigated.The results show that a blank sample which the accompanies the actinometer sample in whole process can effectively eliminate the error caused by the instability of the solution.With the passage of time and the increase of temperature,the chemical actinometer caused an increase in absorbance,and the solution itself increased by a dose of 0.03 J?（m2?h）-1 over time.When the solution was prepared,the different dissolution sequence of sodium tetraborate resulted in a difference of one order of magnitude in absorbance at 352 nm.The photochemical reaction mainly occurs on the surface of the liquid,so stirring was required during the experiment.The accompanying blank sample proposed here theoretically can remove all the influences including those from unknown factors.（2）It reveals the fact that in CBA,the“collimated beam”is not really collimated.A mathematical model of CBA was established,and the influencing factors and specifications of CBA were strictly analyzed:the distance between the ultraviolet lamp and the irradiated object should be within the range of 170～530mm,the threshold of the upper hole diameter threshold was 30～65 mm,and the diameter of lower aperture should be enough smaller than the diameter of the container（glass dish or beaker）to prevent the beam from reaching the side wall of the container.The influence of the reflection of the tube inner wall of the tube CBA on the measurement was investigated,and the result showed that the relative error range caused by the reflection from the inner surface of the tube was 4.11%～8.35%.The aperture type of CBA not only has high measurement accuracy,but also is suitable for the calibration of radiometers with chemical actinometer.（3）The measurement errors of UV irradiance caused by the reflective light from the surrounding environment and the method to eliminate such errors were studied.The reflection environment,the position and width of the baffle,and the influence of the slit plate on the reflection measurement were investigated.The results show that the surrounding environment had a great influence on the reflection of light,and the maximum illuminance error caused by reflection is as high as 28.4%.The calculation formulas of the key parameters required by the anti-reflection measurement system were derived.Setting a plate with a slit can avoid the influence of reflection on the measurement,realize small space measurement,and greatly reduce the measurement cost.（4）A method for measuring the UV output of the underwater combination of an UV lamp and the quartz sleeve was established.Two probes are set.One is above the lamp,another is under the lamp.The modification coefficient can be obtained through adjusting the water level.The influences of water level,water temperature,air bubbles on the lower probe,and the measurement distance on the upper probe were investigated.The results show that the water level and air bubbles had no effect on the lower probe.The change in water temperature caused the lower quartz window to fog,so the water mist should be removed during measurement,and then the reading of the lower probe;and when the temperature changed,the modification coefficient（E2/E1）was still maintained at about 1 when the submergence ratio was 71.2%.In order to ensure the accuracy of the measurement,while following the relative measurement distance range of L/2-4L,the absolute distance between the lamp and the probe should also be considered:the upper probe and the UV lamp should maintain a sufficient distance,and the measurement distance should be greater than 300 mm.The measurement method of an underwater UV lamp in this work is accurate and effective.（5）The statistical analysis was performed on the experimental measurement data of water level,air bubbles,stirring,and room light factors with statistical significance,which provided a statistical analysis basis for the analysis and judgment of experimental results. |
