CN2859515Y

CN2859515Y - Ultraviolet multi-spectrum on-line water quality COD rapid survey instrument

Info

Publication number: CN2859515Y
Application number: CN 200520102594
Authority: CN
Inventors: 王晓萍; 林帧
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2005-06-01
Filing date: 2005-06-01
Publication date: 2007-01-17
Anticipated expiration: 2015-06-01

Abstract

This utility model discloses a ultraviolet multi-spectrum online water quality COD rapid measuring instruments. Embedded microcomputer system is linked with network communication interface, LCD liquid crystal display and touch-screen respectively, the control signal of embedded microcomputer system is connected with spectrum scanning step motor,measure valve and clearing valve respectively, circulation measures groove is connected with automatic washing equipment,water sample outlet, clearing valve and measure valve respectively, measure valve is connected with inlet of water sample to be measured, ultraviolet light emitted by deuterium lamp passes through the measuring groove after gathering together, the ultraviolet light after being absorbed by water sample is forcused and irradiate plane grating optical splitting system. After being splited, it irradiate silicon photodiode which is connected with embedded microcomputer system. This utility model has improved the applicability and measures accuracy of COD measuring instrument based on ultraviolet absorption; It has achieved the goal of picking up water sample, cleansing measure groove and measuring full automatically, improving the speed of online measure and suited for CODs analysis test on environmental water and various waste water in the way of online,rapid and accurate.

Description

The multispectral online water-quality COD instrument for quick measuring of ultraviolet

Technical field

The utility model relates to the multispectral online water-quality COD instrument for quick measuring of a kind of ultraviolet, relates in particular to the technological improvement of multispectral absorbance of full ultraviolet light wave band and self-adaptation, the online instrument for quick measuring of BP neural network realization water-quality COD.

Background technology

Chemical oxygen demand (COD) (Chemical Oxygen Demand, be called for short COD) is the representative index of water quality organic pollutants, at water environment protection with in administering, all must survey project with this parameter as what characterize the water pollution degree both at home and abroad.The domestic and international at present measuring method to the COD parameter mainly contains: adopt potassium dichromate method (CODcr method) for waste water, adopt permanganimetric method (CODMn) for surface water, ultraviolet absorptivity method (UV method) can be measured waste water and surface water simultaneously.Because the UV method has non-secondary pollution and the fast advantage of measuring speed, having presented in the current measurement at the scene has the trend that replaces the CODcr method.The existing abroad ripe product of UV method has obtained general application in Europe and Japan, and domestic also have introduction, but still do not have the ultraviolet all band UV method COD surveying instrument of oneself developing.

External UV method COD measuring instrument mostly adopts the absorbance of the single wavelength of ultraviolet light 254 (253.7) nm, by setting up 254nm absorbance A ₂₅₄With the linear dependence relation between the different water sample COD, converting obtains the numerical value of COD.Why select 254nm, this is because it just is the main radiation wavelength of low pressure mercury lamp.Converting with the absorbance of single ultraviolet wavelength obtains the COD value, is feasible theoretically, and the water sample single and stable at some component also can obtain certain effect in practicality.But its maximum absorbing wavelength of the waste water of in fact different factories and different surface water is not to be fixed on 254nm, and changes with the difference of the contained organic contaminant of water sample, is subjected to the influence of many factors such as suspension and grain size thereof in the water body.With single absorbance and COD set up linear dependence relation do not meet can not reflect water body have different wave length ultraviolet absorption peak and and the COD value between exist the actual conditions of nonlinear relationship, use existing UV method measuring instrument in applicability and accuracy thereof to different water bodys, aspects such as the networking of data communication all have been subjected to very big restriction.

Summary of the invention

The purpose of this utility model provides the multispectral online water-quality COD instrument for quick measuring of a kind of ultraviolet.

Embedded pc system respectively with network communication interface, LCD liquid crystal display and touch-screen join, the control signal of embedded pc system is connected to the spectral scan stepper motor successively, measure valve, cleaning valve, the circulation measuring flume respectively with automatic flushing device, the water sample outlet, cleaning valve, the measurement valve joins, cleaning valve and rinse water import are joined, measuring valve and detected water sample import joins, the ultraviolet light that the deuterium lamp light source sends passes through measuring flume after assembling, incided the plane grating beam splitting system by the ultraviolet light after the water sample absorption through overconvergence, incide silicon photoelectric diode after the beam split, silicon photoelectric diode and embedded pc system join.

The utility model has improved the applicability and the measurement accuracy of this COD measuring instrument owing to adopt the online COD measuring technique of UV method of the multispectral automatic scanning system of ultraviolet, embedded pc system and neural network composition; Realized that based on the monitoring software of embedded real-time operating system water sample extraction, measuring flume clean and the full-automation of whole measuring process; Needed only 3 minutes the measuring period of the multispectral online water-quality COD measuring instrument of ultraviolet, improved the COD measuring speed greatly; Multispectral absorbance of setting up by the BP neural network of ultraviolet and the mathematical model between the water sample COD more meet water sample and have the actual conditions that have nonlinear relationship between multiple pollutant and absorbance and the COD value.Therefore enlarge the scope of application of instrument, can be suitable for online, the analytical test fast and accurately of Environmental Water and all kinds of waste water CODs.

Description of drawings

Fig. 1 is the multispectral online water-quality COD instrument for quick measuring block diagram of ultraviolet;

Fig. 2 is a ultraviolet spectrometry spectral scan system schematic;

Fig. 3 is the multispectral online water-quality COD instrument for quick measuring software flow pattern of ultraviolet;

Fig. 4 is a BP neural network synoptic diagram of setting up mathematical model between multispectral absorbance of ultraviolet and the water-quality COD.

Embodiment:

As shown in Figure 1: the online water-quality COD measuring instrument of the multispectral autoscan formula of ultraviolet of the present utility model is connected with several parts such as pipeline, automatic flushing device, ultraviolet spectrometry spectral scan system, IntelStrong ARM embedded pc system, network communication interface, LCD LCD and touch-screens and is formed by circulation measuring flume, solenoid valve.Embedded pc system is finished the collection of each wavelength absorbance signal in the ultraviolet light all band, and the spectrum numerical value of demarcating according to blank, obtain 8 bigger absorbances of detected water sample and absorbance and each the absorbance sum of 400nm through data processing, import the BP neural network model of having finished through similar water quality sample training again, calculate the COD data that obtain this measurement; Measurement data can be preserved for a long time, shows on LCD and local, remote transmission.The soft machine realization of the monitoring of described embedded pc system is cleaned pump valve to detected water sample water inlet pump valve, plane grating beam splitting system stepper motor and the accurate control of cleaning stepper motor and the realization of measuring instrument repertoire automatically.

As shown in Figure 2: the ultraviolet multispectral scanning system, be to be made of deuterium lamp light source 1, first convergent lens 2, second convergent lens 4, plane grating beam splitting system, silicon photoelectric diode 11, wherein the plane grating beam splitting system is joined with entrance slit 5, collimator objective 6, plane grating 8, collecting objective 7, plane grating 8, stepper motor 9, exit slit 10 successively.The light that deuterium lamp 1 is sent becomes directional light after by convergent lens 2, in silica glass window circulates measuring flume 3, entered entrance slit 5 by the light after the water sample absorption through convergent lens 4, after collimator objective 6 reflections, become directional light and put into plane grating 8 surfaces, grating resolves into spectrum as dispersion element with the complex light diffraction that receives, line focus object lens 7 are assembled the back to exit slit 10, form a series of monochromatic slit images that wavelength is arranged of pressing.By the motion of embedded system 12 control step motors 9, can scan and obtain the absorption light intensity of 200nm to the whole wave band intrinsic resolution of 400nm each wavelength that is 1nm, enter silicon photoelectric diode 11.Photodiode converts received light intensity signal to corresponding electric signal, therefore can obtain the light intensity signal of all band ultraviolet light after detected water sample absorbs, the spectrum numerical value of the pure water that obtains according to blank timing signal again calculates the absorbance of each wavelength.

The light path of plane grating beam splitting system adopts the Czerney-Turne pattern, imports and exports the wide selection 0.5mm of slit seam, and light-splitting device adopts the plane blazed grating of 1200g/mm.The focal length of collimator objective and focusing objective len is 200nm, relative aperture D/F=1/4.5, and the wavelength resolution ability is less than 0.5nm.The scanning that the control step motor just changes, counter-rotating and speed change realize ultraviolet band, the resolution of scanning wavelength is 1nm.

Fig. 3 is the main flow chart of the online water-quality COD measuring instrument of the multispectral autoscan formula of ultraviolet monitoring software.Carry out initialization after instrument powers on earlier, open pump and water intaking valve then, make the detected water sample formula measuring flume that circulates; After treating waterflow stabilization, the control optical system is carried out the ultra-violet absorption spectrum that ultraviolet band scanning obtains water sample, according to the spectrum numerical value that blank is demarcated, calculates the absorbance of each wavelength; Therefrom obtain absorbance and the absorbance sum of 8 bigger absorbances, 400nm; Use the BP-LM fast algorithm of neural network model to extrapolate the COD value of water sample again; At last to measurement data show, processing such as alarm decision and preservation.Except that this main flow, the operation that program can respond button realizes the functions such as setting of blank demarcation, data query, running parameter; And can regularly clean automatically.

As shown in Figure 4: according to the full wave a plurality of absorbance datas of ultraviolet, adopt the BP artificial neural network to set up the mathematical model of spectroscopic data and organic contamination substrate concentration (COD), and, extrapolate the COD data of this water sample by a plurality of ultraviolet light absorption degrees of data of detected water sample by the extrapolability of this model.The BP artificial neural network layer structure that native system is set up is 10-20-1.Input layer is 10 nodes, imports resulting 8 big absorbance datas in the ultraviolet light wave band respectively, and the 9th is the absorbance data (as the reference signal of influence factors such as light source, particle) of visible light 400nm wavelength, and the 10th is the absorbance sum.Hidden layer adopts 20 nodes, and output layer is 1 node, promptly is to calculate the COD data that obtain through this artificial neural network.

Claims

1, the online water-quality COD measuring instrument of the multispectral autoscan formula of a kind of ultraviolet, it is characterized in that, embedded pc system respectively with network communication interface, LCD liquid crystal display and touch-screen join, the control signal of embedded pc system is connected to the spectral scan stepper motor successively, measure valve, cleaning valve, the circulation measuring flume respectively with automatic flushing device, the water sample outlet, cleaning valve, the measurement valve joins, cleaning valve and rinse water import are joined, measuring valve and detected water sample import joins, the ultraviolet light that the deuterium lamp light source sends passes through measuring flume after assembling, incided the plane grating beam splitting system by the ultraviolet light after the water sample absorption through overconvergence, incide silicon photoelectric diode after the beam split, silicon photoelectric diode and embedded pc system join.

2, the online water-quality COD measuring instrument of the multispectral autoscan formula of a kind of ultraviolet according to claim 1, it is characterized in that, described ultraviolet multispectral scanning system is made of deuterium lamp light source 1, first convergent lens 2, second convergent lens 4, plane grating beam splitting system, silicon photoelectric diode 11, and wherein the plane grating beam splitting system is joined with entrance slit 5, collimator objective 6, plane grating 8, collecting objective 7, plane grating 8, stepper motor 9, exit slit 10 successively.