Design Of Submerged Variable Optical Path Spectral Probe For Water Quality Monitoring Based On UV-VIS Spectroscopy

Water resource shortage and serious water environment pollution put forward higher requirements on water quality detection technology. Spectroscopy water quality testing technique as a simple, rapid, and no secondary pollution new water quality measurement method, is becoming a modern quality detection(monitoring) technology research hotspot.In spectroscopy water quality measurement system, spectral probe composed of light source, optical path, sample pool, is not only an important part of the system, but also plays an irreplaceable role on the accurate measurement of water quality parameters. In particular, in-situ measurement method is often used in order to ensure real-time and accuracy of measurement. Thus, the design and manufacturing technology of submerged spectral probe has become one of the key technologies of spectroscopy water quality measurement.At present, the spectral probe is monopolized mainly by foreign companies, such as America Ocean Optics, Hach, Austria S::CAN and Netherlands Avantes, etc. Domestic probe research is still in the exploratory stage, there are many problems in the spectral probe design. For example, low coupling efficiency between light source and the optical fiber, serious stray light interference, low ultraviolet light transmittance and large structure size of spectral probe, result in that water quality monitoring equipment spectral probe is purchased heavily from abroad whose price is greatly expensive, so it is hard to promote application range of spectral probe.This paper studied research status at home and abroad and development trend of spectroscopy water quality detection technology systematically, faced with the existing problems of spectral probe playing a crucial role on accuracy, repeatability, stability of water quality measurement, proposed a structure scheme of submerged variable optical path spectral probe integrating light source, optical system, photoelectric detection system. Based on this, applied optical basic theoretical knowledge, utilized ZEMAX and TracePro optical simulation software to complete system design, optimization and performance analysis research work. Research results showed that condensing efficiency of the light source was up to 82.69%, the transmission efficiency of the optical system was 44.20%, the system had 2nm resolution ratio, the size of the entire system was 630mm×100mm×100mm, which could meet the water quality monitoring system's demands of real-time, fast, multi-parameter detection After completed the system design, made use of ZEMAX to analyze tolerance, results showed that the design of the spectral probe meet the production process and assembly requirements. Finally, completed optical drawings of spectral probe using AutoCAD. Therefore, this thesis breaks through key technologies such as miniaturization design, light concentrator design, fiber-coupled design, photoelectric detection system wide spectrum application design and so on, has important practical significance to the development of optical probe and the on-line, real-time measurement application of water quality monitoring instrument.