Design Of Dust Concentration Detecting System Based On β-Radiation-Absorption-Method

Dust concentration detecting has developed more and more promptly and played a significant part in many conditions, such as the application of powder in industry-product-line and the identification of environmental quality. At present, there are a lot of different kinds of measuring methods at home and abroad, which have various features and application ranges.The thesis aims at providing a practical and novel dust concentration detecting instrument, which can automatically realize dust sampling, radiation intensity measuring, data processing, results feedback and parameters setting, etc. Besides, the system will be able to run continuously on-line. The working principle is based onβ-radiation-absorption-method: The intensity ofβradiation is weakened by the transmission through matter and the relationship between the two intensities is a measure of the thickness of matter.The following four aspects are what this paper has studied on:1. basing on comparing the advantages and disadvantages of different dust concentration detecting methods as well as combing the development situation in our country, design the dust concentration detecting system employed ARM processor S3C44B0X as the core component andβ-radiation-absorption-method as the measuring principle;2. discuss the theory ofβ-radiation-absorption-method in detail; on the basis of analyzing the mathematical module, put forward three critical parameters: n 0,n and Q; according to the measuring requirements and the characteristic of ARM processor, select appropriate sensor, power source, motor and other devices so as to build the whole system framework, including the mechanical structure, actuating mechanism and so on; analyze the factors which can influence the measuring accuracy as well as the relevant solutions;3. complete the hardware design of each modules based on the ARM processor, mainly including: the human-machine interface using LCD and TSP, the filter transfer controlling unit, the radiation intensity detecting unit, the constant air flow sampling system, the adapter motion controlling unit and so on; make the maximum effort to optimize the system structure and reduce the cost on condition that all the measurement indexes are realized; 4. fulfill the software development according to the hardware design of each modules; using relevant algorithm to realize the sampling, processing of signal and the feedback of results; by solving lots of specific problems occurring in the controlling process, improve the working accuracy and reliability of the system.