| Online near-infrared spectroscopy (NIRS) system is a kind of analytical instruments with advanced technology. The system is based on the technology of NIRS and Industrial Automation, which can be widely used at pharmaceutical industry,food industry and petrochemical industry, because of its benefits on high-speed,clean and real-time measurement of multi-component. However, with one problem appeared and become more and more popular in domestic analytical instruments, that is, the maintenance costs is unbearable for many equipment manufacturers because of poor reliability. Therefore, how to improve the reliability of the Field Analytical Instrument produced by national manufacturers becomes a question which was difficult but necessary to improve. This article was written to study on reliability of online near-infrared spectroscopy system. The chief content of this article are listed as follows:First, The phylogeny of technique in near-infrared spectroscopy and the problem we encountered in online apparatus were introduced briefly, also the development of reliability and its' application in the area of apparatus were summarized. Due to the development of near infrared analytical instrument and the characteristics of its'application, the necessity of improving the reliability of NIRS system was presented.Second, the correlative theory of reliability project is expatiated, and the importance of invalidation analysis in dependability work was point out. The author gave the definition and common mode of invalidation in analytic apparatus. According to the characters of analytical method in invalidation and analytic apparatus, the author put forward a common analytical process in invalidation diagnosis.Third, Measurement principle of infrared spectrometer system was expatiated. The author narrated its' source information, measure technique. Structure and buildup of online near-infrared spectroscopy system was described briefly. Systemic performance was analyzed, and such questions were researched how parameters effects measuring veracities, which is valuable for next invalidation analysis.Fourth, the author participated in research and development, testing, and production of NIR system in-depth. Since the physical structure of online NIR spectrometer includes subsystems of lamp-house, spectrometer, multiplexer and sample pretreatment, every subsystem can be analyzed for invalidation respectively. The author ascertained main mode and mechanism subsystem invalidation, and established fault tree structure based on its' characters respectively. The author also analyzed and simulated how to affect systemic performance by damaging of key components, and took some measure to mend the invalidation. It has been validated by rational experimentation. Systemic test has been carrying out based on reliability requirement of the system, and taking some national standards into account, which includes test for the whole system, reliability surrounding. After observing testing results, we can kwon that key performance parameter of the system could suffice reliability requirement. However, there is a fearful problem of apparatus's temperature sensitivity in the system, which debased reliability obviously. Consequently, we will equip analytical house to keep temperature steady when using NIRS system in special environment.The main mode and mechanism of invalidation is ascertained in this paper, using fault tree analysis theory. There are preventable measures which has been taken in order to improve dependability of the system. |
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