CN204613109U - A kind of Multi-channel optical dissolved oxygen measuring device - Google Patents

Abstract

The utility model discloses a kind of Multi-channel optical dissolved oxygen measuring device, this device comprises can, and be arranged at the excitation source module of can inside, fluorescence generation module, hyperchannel fluorescence reception module, signal processing unit, data acquisition and control module, be arranged at the computer processing unit of can outside, hyperchannel fluorescence reception module comprises three identical fluorescence reception passages, the fluorescence reception angle of three fluorescence reception passages is respectively and becomes 45 degree with fluorescence generation module place plane, 60 degree, 90 degree, and three fluorescence reception passages are positioned at same plane, mutually isolated.The utility model adopts multiple fluorescence reception passage, improve the receiving efficiency of fluorescence, in addition, utilize the fluorescence intensity ratio of every two passages, realize the corresponding relation between this ratio and oxygen concentration, overcome existing based on fluorescence intensity detection method be subject to flashing bring the inferior position of measuring error, make dissolved oxygen sensing result more accurate.

Description

A kind of Multi-channel optical dissolved oxygen measuring device

Technical field

The utility model relates to a kind of Multi-channel optical dissolved oxygen measuring device, belongs to dissolved oxygen sensing technical field.

Background technology

Along with the development of optical sensor, fluorescence analysis and measuring technique have been widely used in the detection of dissolved oxygen concentration in water body, optic dissolution oxygen measuring method based on Fluorescence quenching mechanism instead of traditional iodimetric titration and oxygen electrode method gradually, all has great importance in industrial or agricultural, medical science and environmental monitoring field etc. to the detection of oxygen in water concentration.

But, in many existing technology, as one section of invention (publication number: CN 1731154A), one section of utility model (publication number: CN 2014788947 U) of China, the two measuring method that all have employed based on fluorescence intensity measures dissolved oxygen concentration in water body, this will bring the error produced due to factors such as light source fluctuations, reduces the accuracy of system sensitivity and measurement result.Although and in measuring accuracy, had raising based on the method for the measurement of fluorescence lifetime, measuring process relative complex, Measuring Time is longer.

In addition, measuring method majority based on fluorescence intensity adopts single pass receive optical structure, be fluorescence intensity and dissolved oxygen concentration by producing be that corresponding linear relationship directly realizes dissolved oxygen sensing, due to the change of the intensity of light source, can measuring error be increased undoubtedly, cause the measuring precision not high.And excite the fluorescence of generation to be a kind of scattered light, single pass receive optical structure itself also can reduce the receiving efficiency of fluorescence, thus brings the inferior position that dissolved oxygen concentration measurement range is less, is also unfavorable for the practical development of dissolved oxygen sensing system.

Further, measurement for dissolved oxygen DO also have use optical fiber using realize exciting light transmission and fluorescence reception according to laser as exciting light, because energy is higher, this will shorten the life-span of sensitive fluorescent membrane greatly, and adopt light emitting diode (LED), need consider how exciting light source and fluorescence are coupled into optical fiber efficiently, even if the LED light source using band tail optical fiber to export, also can bring the increase on cost undoubtedly.Meanwhile, optical fiber type dissolved oxygen measuring device majority is a kind of structure of discrete detection, causes the integrated level of whole measuring system not high.

Finally, in many existing technology, when adopting the method measurement dissolved oxygen DO based on fluorescence intensity, at collection fluorescence signal in data analysis, process and linear fitting procedure, the method precision adopted is not very high, as least square method, the detection for dissolved oxygen concentration not only needs high-precision data processing circuit, and needs good data processing, linear fit method.

Utility model content

Technical problem to be solved in the utility model is: provide a kind of Multi-channel optical dissolved oxygen measuring device, improve the receiving efficiency of fluorescence, overcome the existing measuring error brought because of flashing based on fluorescence intensity detection method, make dissolved oxygen sensing result more accurate, improve the long-term reliability of measurement mechanism.

The utility model is for solving the problems of the technologies described above by the following technical solutions:

A kind of Multi-channel optical dissolved oxygen measuring device, comprise can, and be arranged at the excitation source module of can inside, fluorescence generation module, hyperchannel fluorescence reception module, signal processing unit, data acquisition and control module, also comprise the computer processing unit being arranged at can outside, described hyperchannel fluorescence reception module comprises three identical fluorescence reception passages, penetrate along fluorescence the direction come in each fluorescence reception passage and be disposed with band pass filter, light condenser lens, photodetector, the fluorescence reception angle of three fluorescence reception passages is respectively and becomes 45 degree with fluorescence generation module place plane, 60 degree, 90 degree, and three fluorescence reception passages are positioned at same plane, mutually isolated,

Described excitation source module produces excitation light to fluorescence generation module, fluorescence generation module receives exciting light and produces fluorescence, this fluorescence is directive three fluorescence reception passages respectively, and in each fluorescence reception passage successively after band pass filter, light condenser lens by photoelectric detector, photodetector, signal processing unit, data acquisition are connected successively with control module, computer processing unit.

Preferably, described excitation source module comprises light source generator, modulation of source circuit, light source driving circuit, described modulation of source circuit, light source driving circuit are connected with light source generator respectively, and modulation of source circuit, light source driving circuit are also connected with control module with data acquisition respectively.

Preferably, described fluorescence generation module comprises watertight glass sheet, oxygen-sensitive fluorescent membrane, fluorescence sensitivity agent, described watertight glass sheet is embedded in the bottom of can, one of them surface is positioned at the inside of can, another surface and extraneous contact, and be coated with oxygen-sensitive fluorescent membrane and fluorescence sensitivity agent successively with the surface of extraneous contact.

Preferably, described signal processing unit comprises prime amplifier, filtering shaping circuit and accurate RMS-DC converter circuit, the input end of described prime amplifier is connected with the output terminal of each multi-channel photodetector, output terminal connects the input end of accurate RMS-DC converter circuit through filtering shaping circuit, and the output terminal of accurate RMS-DC converter circuit is connected with control module with data acquisition.

Preferably, the material of described can is stainless steel or waterproof high polymer material.

The utility model adopts above technical scheme compared with prior art, has following technique effect:

1, the utility model Multi-channel optical dissolved oxygen measuring device, construct three fluorescence reception passages, accurately measuring dissolved oxygen concentration is realized by the ratio measuring the fluorescence intensity level between two between passage, effectively reduce the impact of intensity of light source change on dissolved oxygen sensing result, reduce measuring error.

2, the utility model Multi-channel optical dissolved oxygen measuring device, have employed effective algorithm, as neural network algorithm realizes, to the fusion treatment of three ratio data between two between passage, reducing the uncertainty of oxygen concentration testing.

3, the utility model Multi-channel optical dissolved oxygen measuring device, adopts multi-channel data integration technology, makes dissolved oxygen sensing result more accurate, improves the long-term reliability of dissolved oxygen measuring device.

Accompanying drawing explanation

Fig. 1 is the structural representation of the utility model Multi-channel optical dissolved oxygen measuring device.

Fig. 2 is the workflow diagram of the utility model Multi-channel optical dissolved oxygen measuring device.

Fig. 3 is the test result figure of the utility model three output characteristic curves.

Fig. 4 is the RBF three layer feedforward neural networks structural drawing that the utility model adopts.

Fig. 5 is the calibration graph obtained after the utility model three output characteristic curve data fusion.

Wherein: 1 is light source generator; 2 is light source driving circuit; 3 is modulation of source circuit; 4 is exciting light; 5 is watertight glass sheet; 6 is oxygen-sensitive fluorescent membrane; 7 is fluorescence sensitivity agent; 8 is fluorescence; 9 is light division board; 10 is bandpass filter; 11 is light condenser lens; 12 is photodetector; 13 is signal processing unit; 14 is data acquisition and control module; 15, computer processing unit; 16, can.

Embodiment

Be described below in detail embodiment of the present utility model, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Being exemplary below by the embodiment be described with reference to the drawings, only for explaining the utility model, and can not being interpreted as restriction of the present utility model.

As shown in Figure 1, be a preferred embodiment of a kind of Multi-channel optical dissolved oxygen measuring device of the utility model.This measurement mechanism mainly comprises following components: for generation of exciting light 4 excitation source module, for receiving exciting light and producing the fluorescence generation module of fluorescence 8, hyperchannel fluorescence reception module, signal processing unit, data acquisition and control module, computer processing unit, also have a can in addition.

Excitation source module in the present embodiment, comprises light source generator 1, light source driving circuit 2, modulation of source circuit 3.Preferably, light source generator is that high-brightness blue is emitting led, and wavelength coverage is 455-468nm, and making to export the wavelength of light by modulation of source circuit 3 is 460nm, and light source driving circuit 2 provides stable power stage for light source.Light source driving circuit 2, modulation of source circuit 3 are electrically connected with control module 14 with data acquisition.

Fluorescence generation module in the present embodiment, comprise the oxygen-sensitive fluorescent membrane 6 being coated on a watertight glass sheet 5 wherein surface, and be evenly coated on the fluorescence sensitivity agent 7 on oxygen-sensitive fluorescent membrane surface, watertight glass sheet 5 surface and an extraneous contact wherein, another side is encapsulated in housing lower inner wall, and realizes sealing arrangement well.Preferably, watertight glass sheet 5 adopts quartzy material to form, and Mohs value is 9.0, compressive strength 20Mpa, and transmittance reaches 95%.Preferably, oxygen-sensitive fluorescent membrane 6 in the present embodiment take ruthenium complex as Fluorescence sensitized material, prepared by sol-gel technique, Fluorescence sensitized material can be selected from the various Fluorescence sensitized materials of existing discovery, is preferably Ru (dpp) in the present embodiment ₃cl ₂, described fluorescence sensitivity agent 7 also can be selected from the various fluorescence sensitivity agent of existing discovery, is preferably beta-schardinger dextrin-or derivatives thereof in the present embodiment.

Hyperchannel fluorescence reception module in the present embodiment has three independently fluorescence reception passages, each independently light-receiving passage be all be made up of light division board 9, bandpass filter 10, light condenser lens 11, photodetector 12 is mounted with successively in passage, and bandpass filter, light condenser lens be centrally located on same straight line, photodetector is positioned at the focus place of light condenser lens.Bandpass filter 10 in the present embodiment is the bandpass filter of a centre wavelength 610 ± 5nm, bandwidth ± 30nm.Photodetector can be selected from existing photo-detector, and be preferably PIN type photodiode in the present embodiment, wavelength detection scope is 200-1100nm.

Signal processing unit 13 correspondence three independently fluorescence reception channel output end in the present embodiment, comprises prime amplifier, filtering shaping circuit, accurate RMS-DC converter circuit etc.Data acquisition is electrically connected with Photoelectric Signal Processing unit with control module 14, is also electrically connected with modulation of source circuit, light source driving circuit, computer processing unit simultaneously.

In addition, the material of the can 16 in embodiment is preferably the macromolecular material of stainless steel or waterproof, as PVC, ABS high polymer material.

As shown in Figure 2, for the course of work of the utility model Multi-channel optical dissolved oxygen measuring device, first the master controller in data acquisition and control module sends pulse train, and control modulation of source circuit and modulate light source, light source driving circuit provides stably power stage for it.Then, exciting light incides on oxygen-sensitive fluorescent membrane through watertight glass sheet, oxygen-sensitive fluorescent membrane is excited to produce fluorescence, respectively become with same watertight glass sheet place plane 90 degree, 60 degree, 45 degree three directions adopt three independently passage realize the reception of fluorescence signal, in this process, fluorescence is by being received by PIN type photodiode after bandpass filter, light condenser lens.Finally, realize opto-electronic conversion by signal processing unit, the d. c. voltage signal size after conversion is directly proportional to fluorescence intensity signals size, then delivers to computer processing unit process through data acquisition and control module, obtains dissolved oxygen concentration value.

For the ease of understanding technical solutions of the utility model further, below the measuring principle of above-mentioned a kind of Multi-channel optical dissolved oxygen measuring device and method are briefly described.

Multi-channel optical dissolved oxygen sensing principle of the present utility model is based on Fluorescence quenching mechanism, three fluorescence reception channel architectures are adopted to realize the efficient reception of fluorescence, by the fluorescence signal value of channel reception is between two made division operation, realize the ratio of fluorescence signal value and the fluorescence signal value of wide-angle becoming low-angle autonomous channel to receive with watertight glass sheet place plane, i.e. 45 ° of direction signal value F ₁with 60 ° of direction signal value F ₂ratio, 60 ° of direction signal value F ₂with 90 ° of direction signal value F ₃ratio, 45 ° of direction signal value F ₁with the ratio F of 90 ° of direction signal values ₃, this ratio is defined as output characteristics parameter A, namely

$\begin{array}{ccc}{A}_1=\frac{F_1}{F_2}& A_2=\frac{F_2}{F_3}& A_3=\frac{F_1}{F_3}\end{array}---\left(1\right)$

By measuring lower three the photosignal values of different dissolved oxygen concentration simultaneously, obtain the size of output characteristics parameter A, obtain three output characteristic curves by formula (1), then with RBF neural algorithm, data fusion is carried out to these three output characteristic curves, obtain calibration curve.

Further checking is done to the utility model measurement mechanism accuracy below, with RSS-5100 type dissolved oxygen instrument, in advance process is demarcated every 0.5mg/L respectively to the oxygen concentration within the scope of 0-18mg/L, measure the photosignal value of three passages simultaneously, obtain 3 × 37 output characteristics parameters, every 37 output characteristics parameters determine an output characteristic curve, obtain three output characteristic curves altogether, as shown in Figure 3, curve 1 is 37 A ₁the curve be linked to be, curve 2 is 37 A ₂the curve be linked to be, curve 3 is 37 A ₃the curve be linked to be.Slope of a curve reflects the sensitivity of measuring system, when dissolved oxygen concentration scope is at 0-7mg/L, chooses curve 1 for data sample, and when 7-11mg/L, choosing curve 2 is data sample, and when 11-18mg/L, choosing curve 3 is data sample.

As shown in Figure 4, be a kind of RBF three layer feedforward neural networks structural drawing.Ground floor and input layer are made up of signal source node; The second layer is hidden layer, and by the needs of implicit unit number depending on described problem, the transforming function transformation function of implicit unit is Gaussian function, namely

${\mathrm{\ψ}}_i\left(\right|\left|{X-c}_i\right|\left|\right)=\exp [-\frac{{\left|\right|{X-c}_i\left|\right|}^2}{{{2\mathrm{\σ}}_i}^2}],(i=\mathrm{1,2},...m)---\left(2\right)$

Wherein, ψ _i(|| x-c _i||) be the output of i-th implicit node, X=(x ₁, x ₂, x ₃x _p) ^tfor input amendment vector; c _ibe the center of the Gaussian function of i-th hidden layer node and have identical dimension with x; σ _ibe the variable of i-th hidden layer node, claim generalized constant, or sound stage width degree; M is the number of hidden layer node.It is symcenter radial symmetry and the nonlinear function of decay; Third layer is output layer, and it makes response to the effect of input pattern, and adopt linear function as activation function, output layer i-th neuron is

${\mathrm{\γ}}_i=\underset{i}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\ω}}_{\mathrm{ik}}{\mathrm{\ψ}}_i\left(\right|\left|{X-c}_i\right|\left|\right)+\mathrm{\β},(i=\mathrm{1,2},...,m)---\left(3\right)$

In formula, ω _ikfor output layer neural network weight, β is deviation.

The characteristic parameters got in 0-7mg/L, 7-11mg/L, 11-18mg/L tri-sections of oxygen ranges inputs as network, and the demarcation oxygen concentration of corresponding RSS-5100 type oxygen analyser is network desired output, and namely the input layer of network and output layer nodes are all 1.Adopt KM algorithm to carry out cluster to training sample, using the classification number divided as node in hidden layer, the center being radial basis function with all kinds of centers, all kinds of variances is transformed to width parameter.Initialized network weight, learning rate and deviation, train in the data sample input RBF algorithm in these three sections of oxygen ranges respectively, result as shown in Figure 5, horizontal ordinate represents actual dissolved oxygen concentration, ordinate represents the output oxygen concentration value of this measuring system after matching, Fig. 5 is equal to calibration curve, shows to adopt hyperchannel dissolved oxygen sensing method and Data fusion technique, and test value is close to true value.As long as the fluorescence intensity level recording three passages during real work, carry out data acquisition by signal processing unit processes, again and be input to computer processing unit, corresponding dissolved oxygen concentration value can be obtained according to formula (1), (2), (3).

Above embodiment is only and technological thought of the present utility model is described; protection domain of the present utility model can not be limited with this; every technological thought according to the utility model proposes, any change that technical scheme basis is done, all falls within the utility model protection domain.

Claims (5)

1. a Multi-channel optical dissolved oxygen measuring device, it is characterized in that: comprise can, and be arranged at the excitation source module of can inside, fluorescence generation module, hyperchannel fluorescence reception module, signal processing unit, data acquisition and control module, also comprise the computer processing unit being arranged at can outside, described hyperchannel fluorescence reception module comprises three identical fluorescence reception passages, penetrate along fluorescence the direction come in each fluorescence reception passage and be disposed with band pass filter, light condenser lens, photodetector, the fluorescence reception angle of three fluorescence reception passages is respectively and becomes 45 degree with fluorescence generation module place plane, 60 degree, 90 degree, and three fluorescence reception passages are positioned at same plane, mutually isolated,

Described excitation source module produces excitation light to fluorescence generation module, fluorescence generation module receives exciting light and produces fluorescence, this fluorescence is directive three fluorescence reception passages respectively, and in each fluorescence reception passage successively after band pass filter, light condenser lens by photoelectric detector, photodetector, signal processing unit, data acquisition are connected successively with control module, computer processing unit.

2. Multi-channel optical dissolved oxygen measuring device as claimed in claim 1, it is characterized in that: described excitation source module comprises light source generator, modulation of source circuit, light source driving circuit, described modulation of source circuit, light source driving circuit are connected with light source generator respectively, and modulation of source circuit, light source driving circuit are also connected with control module with data acquisition respectively.

3. Multi-channel optical dissolved oxygen measuring device as claimed in claim 1, it is characterized in that: described fluorescence generation module comprises watertight glass sheet, oxygen-sensitive fluorescent membrane, fluorescence sensitivity agent, described watertight glass sheet is embedded in the bottom of can, one of them surface is positioned at the inside of can, another surface and extraneous contact, and be coated with oxygen-sensitive fluorescent membrane and fluorescence sensitivity agent successively with the surface of extraneous contact.

4. Multi-channel optical dissolved oxygen measuring device as claimed in claim 1, it is characterized in that: described signal processing unit comprises prime amplifier, filtering shaping circuit and accurate RMS-DC converter circuit, the input end of described prime amplifier is connected with the output terminal of each multi-channel photodetector, output terminal connects the input end of accurate RMS-DC converter circuit through filtering shaping circuit, and the output terminal of accurate RMS-DC converter circuit is connected with control module with data acquisition.

5. Multi-channel optical dissolved oxygen measuring device as claimed in claim 1, is characterized in that: the material of described can is stainless steel or waterproof high polymer material.