CN101825564A - Optical detection method for continuously monitoring liquid concentration for a long time - Google Patents

Abstract

The invention discloses an optical detection method for continuously monitoring liquid concentration for a long time. The method comprises the following steps of: (1) selecting two different wavelengths lambda' and lambda'' according to the absorbency index standard curves of solution to be tested and reference solution, wherein the two types of solution have different absorbency indexes on the same wavelength; (2) partitioning a chamber of fixed optical path into a solution to be tested chamber and a reference solution chamber through a light-transmitting device and injecting the solution to be tested and reference solution into the solution to be tested chamber and the reference solution chamber respectively; (3) making parallel rays incident from one end of the chamber of the fixed optical path, pass through the solution to be tested, the light-transmitting device and the reference solution and emergent from the other end of the chamber and recording the light intensities of emergent light at the positions of wavelengths lambda' and lambda'' at the moment; (4) in the state of keeping the light rays pass through the solution to be tested, the light-transmitting device and the reference solution, moving the light-transmitting device to change the optical paths of the solution to be tested and the reference solution, keeping the pressure intensities of the solution to be tested and the reference solution invariable and recording the light intensities of the emergent light at the positions of wavelengths lambda' and lambda'' at the moment; and (5) obtaining a current concentration value of the solution to be tested through a formula shown in the specifications.

Description

A kind of optical detecting method of long-term continuously monitoring liquid concentration

Technical field

The present invention relates to a kind of optical detecting method, be specifically related to a kind of optical detecting method that is applied to long-term continuously monitoring liquid concentration.

Background technology

Detection technique is to obtain the direct approach of data message, and is most important with informationization to the robotization of process, along with the raising of environmental protection consciousness, strict day by day to the requirement of " three wastes " discharging.Developing rapidly of application demand had higher requirement to detection technique, is mainly reflected in two aspects: (1) continuous monitoring for a long time; (2) testing result accuracy and reliability.

Traditional optical detection principle is according to the Lambert-Beer law, by detecting emission light light intensity and receiving the light light intensity, according to parameters such as extinction constant, light paths to determine solution concentration to be measured.Yet in the process of long-term continuous monitoring, because the timeliness effect of light source will cause the slow drift of emission light light intensity inevitably, reasons such as aging, the corrosion of transmitting terminal and receiving terminal camera lens will cause to receive light light intensity detection error.So the spectrophotometric method checkout equipment must carry out periodic calibrating, to ensure the accuracy and the reliability of testing result.But periodic calibrating exists some following limitations: (1) demarcates the continuity that certainly will interrupt detecting, causes the omission of certain time period solution to be measured, if the demarcation cycle is short, then demarcates frequently, and the probability of omission is just big more; If the demarcation cycle is long, then demarcates and just do not reach intended purposes.(2) for the chemical plant of operation under production equipment that embeds detecting instrument (as plug-in type light transmitting fiber probe) and the high-temperature and high-pressure conditions, the general difficulty of the demarcation of detecting instrument is all bigger, even is difficult to carry out.

Summary of the invention

Technical matters to be solved by this invention provides a kind of optical detecting method of long-term continuously monitoring liquid concentration.

The present invention solves the technical scheme that its technical matters takes: the optical detecting method of this long-term continuously monitoring liquid concentration mainly may further comprise the steps:

(1), choose two different wave length λ ' and λ according to the absorptivity typical curve of solution to be measured and reference solution ", described wavelength X ' and λ " meet the following conditions:

If respectively with ε ₁', ε ₂' expression solution to be measured and reference solution are in the absorptivity of wavelength X ' locate, respectively with ε ₁", ε ₂The absorptivity of " representing that solution to be measured and reference solution are in wavelength X " and locating, then ε ₁' ≠ ε ₂' and ε ₁' ≠ ε ₂";

(2) with light transmission device fixedly the cavity volume of light path be separated into solution cavity to be measured and reference solution chamber, solution cavity to be measured and reference solution chamber are respectively equipped with inlet and outlet, and solution to be measured is injected solution cavity to be measured, and reference solution is injected the reference solution chamber;

(3) make the end incident of parallel rays, and pass solution to be measured, light transmission device and reference solution from the cavity volume of described fixedly light path, again from the other end outgoing of the cavity volume of described fixedly light path, record emergent light this moment wavelength X ' and λ " light intensity of locating is respectively with I ₁' and I ₁" expression;

(4) keeping described light to pass under the state of solution to be measured, light transmission device and reference solution, mobile light transmission device is to change the light path of solution to be measured and reference solution, keep the pressure of solution to be measured and reference solution constant simultaneously, record this moment emergent light wavelength X ' and λ " light intensity of locating is respectively with I ₂' and I ₂" expression;

(5) obtain the current concentration value of solution to be measured by following formula

${\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=\frac{\mathrm{<figure-callout\; id="1"\; label="ln\; I"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">ln</figure-callout>}{I_{}}^{}{{}_1}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;}-{{\mathrm{<figure-callout\; id="2"\; label="ln\; I"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">ln</figure-callout>}I}_2}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;}-{{\mathrm{<figure-callout\; id="1"\; label="ln\; I"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">ln</figure-callout>}I}_1}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;\&prime;}+{{\mathrm{<figure-callout\; id="2"\; label="ln\; I"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">ln</figure-callout>}I}_2}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;\&prime;}}{\mathrm{<figure-callout\; id="2"\; label="ln\; I"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">ln</figure-callout>}{I_{}}^{}{{}_2}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;\&prime;}-{{\mathrm{<figure-callout\; id="1"\; label="ln\; I"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">ln</figure-callout>}I}_1}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;\&prime;}+{{\ln I}_1}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;}-\mathrm{<figure-callout\; id="2"\; label="ln\; I"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">ln</figure-callout>}{I_{}}^{}{{}_2}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">C</figure-callout>}}_2$

In the following formula, C ₁Be the current concentration value of solution to be measured, C ₂Concentration known value for reference solution.

Further, the present invention does following improvement:

(a) concentration by changing solution to be measured and correspondingly repeating said steps (3)～(5) are set up the relation curve of solution absorbency variable quantity to be measured and concentration;

(b) repeating said steps (3)～(4) obtain the current absorbance variable quantity of solution to be measured, and the relation curve of solution absorbency variable quantity to be measured that is obtained by step (a) and concentration obtains the current concentration of solution to be measured again.

Further, the present invention is in step (4), and solution cavity to be measured is communicated with by the solution to be measured of its inlet and outlet with the external world, and the reference solution chamber is communicated with by the reference solution of its inlet and outlet with the external world.

Compared with prior art, the invention has the beneficial effects as follows:

(1) the present invention has solved the stability problem of optical detection apparatus long-time running by to the innovation of optical detection principle and the corresponding techniques scheme is provided, and has promptly solved the environmental interference problem in the testing process.

(2) the stable disturbance quantity A during the present invention can detect traditional optical factors such as (effect of light source timeliness, sensor base) wafing, stable disturbance quantity B disturbing factors such as (factors such as wearing and tearing of camera lens burn into and biological attachment) are eliminated as invariant, make testing result interference-free.

(3) use detection method of the present invention to utilize

Obtain solution concentration to be measured, and by this formula as can be known, solution concentration to be measured is only relevant with reference solution concentration, irrelevant with other disturbing factors, as long as reference solution concentration is accurate, solution concentration then to be measured is just accurate, thereby can demarcate solution concentration to be measured by real-time online, realizes the long-term continuous monitoring to solution concentration to be measured.

(4) the present invention can be applicable to the accurate detection of chemical process, the pollution continuous monitoring of " three wastes ", the tracking and monitoring of marine environment ecological factor.

Description of drawings

Fig. 1 is the fundamental diagram of optical detecting method of the present invention;

Fig. 2 is the structural representation that is used for a kind of pick-up unit of optical detecting method of the present invention.

Wherein, 1. quill, 2. first plunger, 2 '. second plunger, 3. collimating mirror, 4. plunger camera lens, fluid chamber 5. to be measured, liquid inlet and outlet 6. to be measured, 7. printing opacity camera lens, 8. reference liquid inlet and outlet, 9. reference fluid chamber, 10. stepper motor, 11. screw mandrel, 12. hold-down supports, 13. web members, 14. press nut, 15. fixing cavity volume, 16. solution cavity inlet and outlets to be measured, 17. reference solution chamber inlet and outlets, 18. solution cavity to be measured, 19. reference solution chambeies, 20. light transmission devices.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

According to the Lambert-Beer law, under certain condition, a branch of monochromatic collimated beam because of absorbing medium absorption portion luminous energy, causes that the intensity of this single beam reduces by behind the solution of absorbing medium.The relation of the thickness of absorbing medium and the concentration of extinction material and light intensity can be used formula (1) expression:

I _c＝I ₀·e ^-εcL (1)

Wherein, I _CBe the light intensity of emergent light, I ₀Be radiative light intensity, ε is the extinction constant of extinction material, and c is the concentration of extinction material, and L is the light path that detects light.

When implementing optical detecting method of the present invention, as shown in Figure 1, in the fixing fixedly cavity volume 15 of a light path, by light transmission device 20 fixedly cavity volume 15 be separated into solution cavity 18 to be measured and reference solution chamber 19.Solution cavity 18 to be measured is in communication with the outside by solution cavity inlet and outlet 16 to be measured, and reference solution chamber 19 is in communication with the outside by reference solution chamber inlet and outlet 17.When needs when solution are injected in solution cavity 18 to be measured and reference solution chamber 19, extraneous solution can be correspondingly injects from separately inlet and outlet, same, when needs when solution are discharged in solution cavity 18 to be measured and reference solution chamber 19, then can correspondingly discharge to the external world from inlet and outlet separately.Because solution cavity 18 to be measured is in communication with the outside by solution cavity inlet and outlet 16 to be measured, therefore when mobile light transmission device changes the light path of solution to be measured and reference solution, can keep the pressure of solution to be measured and reference solution constant simultaneously.

Solution to be measured is injected solution cavity 18 to be measured, reference solution is injected reference solution chamber 19, make the end incident of parallel rays from whole fixedly cavity volume 15, and pass solution to be measured, light transmission device 20 and reference solution, from the fixedly other end outgoing of the fixedly cavity volume 15 of light path, then formula (1) develops into formula (2) again:

$I_c=I_0\&CenterDot;e^{-{\mathrm{\&epsiv;}}_1{C}_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\&CenterDot;e^{-{\mathrm{\&epsiv;}}_2{C}_2{L}_2}---\left(2\right)$

Wherein, ε ₁, C ₁, L ₁Extinction constant, concentration, the extinction light path of representing solution to be measured respectively, ε ₂, C ₂, L ₂Extinction constant, concentration, the extinction light path of representing reference solution respectively.

If consider the disturbing effect of stable disturbance quantity A factors such as (effect of light source timeliness, sensor base) floating and stable disturbance quantity B (factors such as wearing and tearing of camera lens burn into and biological attachment), then formula (2) can be modified to formula (3):

$I_1=I_0{\&CenterDot;e}^{-{\mathrm{\&epsiv;}}_1{C}_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\&CenterDot;e^{-{\mathrm{\&epsiv;}}_2{C}_2{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}\&CenterDot;e^{-{\mathrm{\&epsiv;}}_A{c}_A{L}_A}\&CenterDot;e^{-{\mathrm{\&epsiv;}}_B{c}_B{L}_B}---\left(3\right)$

Wherein, ε _A, c _A, L _ABe respectively extinction constant, concentration or density, the interference light path of stable disturbance quantity A, ε _B, c _B, L _BBe respectively extinction constant, concentration or density, the interference light path of stable disturbance quantity B, I ₁For absorbing light intensity.

Keeping light to pass under the state of solution to be measured, light transmission device 20 and reference solution, by mobile light transmission device 20 to change the light path of solution to be measured and reference solution, keep the pressure of solution to be measured and reference solution constant simultaneously, that is: when solution cavity to be measured or reference solution chamber become cause its pressure to diminish greatly or light can not be all from solution when needing injection solution, inject solution to be measured or reference solution from corresponding inlet and outlet; Same, when diminishing, solution cavity to be measured or reference solution chamber cause its pressure to become big and needs when discharging solution, can discharge survey solution or reference solution from corresponding inlet and outlet.Stability disturbance quantity A and stable disturbance quantity B all be one for a long time, change procedure slowly, can be considered invariant in front and back in the adjacent detection moment.The light path of supposing solution to be measured has increased step delta L, and the reference solution light path has reduced identical step delta L, and then back one detection side's formula constantly can use formula (4) to indicate.

$I_2=I_0\&CenterDot;e^{-{\mathrm{\&epsiv;}}_1{C}_1({\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+\mathrm{\&Delta;L})}\&CenterDot;e^{-{\mathrm{\&epsiv;}}_2{C}_2(L_2-\mathrm{\&Delta;L})}\&CenterDot;e^{-{\mathrm{\&epsiv;}}_A{c}_A{L}_A}\&CenterDot;e^{-{\mathrm{\&epsiv;}}_B{c}_B{L}_B}---\left(4\right)$

Wherein, I ₂Be detected emergent light intensity after the change in optical path length., carry out conversion again and can obtain formula (5) divided by formula (3) with formula (4):

$\ln \frac{I_1}{I_2}=({\mathrm{\&epsiv;}}_2\&CenterDot;C_2-{\mathrm{\&epsiv;}}_1{C}_1)\&CenterDot;\mathrm{\&Delta;L}---\left(5\right)$

If according to the absorptivity typical curve of solution to be measured and reference solution, choose two different wave length λ ' and λ ", make described wavelength X ' and λ " meet the following conditions:

Suppose respectively with ε ₁', ε ₂' expression solution to be measured and reference solution are in the absorptivity of wavelength X ' locate, respectively with ε ₁", ε ₂The absorptivity of " representing that solution to be measured and reference solution are in wavelength X " and locating, then ε ₁' ≠ ε ₂' and ε ₁" ≠ ε ₂".

Then can obtain following formula (6), thus cancellation unknown quantity Δ L:

$\frac{{{\ln I}_1}^{\&prime;}-{{\ln I}_2}^{\&prime;}}{{{\ln I}_1}^{\&prime;\&prime;}-{{\ln I}_2}^{\&prime;\&prime;}}=\frac{{{\mathrm{\&epsiv;}}_2}^{\&prime;}{C}_2-{{\mathrm{\&epsiv;}}_1}^{\&prime;}{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">C</figure-callout>}}_1}{{{\mathrm{\&epsiv;}}_2}^{\&prime;\&prime;}{C}_2-{{\mathrm{\&epsiv;}}_1}^{\&prime;\&prime;}{C}_1}---\left(6\right)$

Wherein, I ₁', I ₂' be respectively wavelength and be detected light intensity before and after the emission light variable step of λ ', ε ₂' for reference solution is extinction constant under the emission light of λ ' at wavelength, C ₂Be the concentration of reference solution, ε ₁' for solution to be measured is extinction constant under the emission light of λ ' at wavelength, C ₁Concentration for solution to be measured; I ₁", I ₂The light intensity that detects before and after the emission light variable step of " being respectively wavelength is λ ", ε ₂Extinction constant under the emission light of " for reference solution is λ at wavelength ", ε ₁Extinction constant under the emission light of " for solution to be measured is λ at wavelength "; I ₁', I ₂', I ₁" and I ₂" can obtain ε by detection ₂', ε ₁', ε ₂" and ε ₁" these constants can obtain by time domain or frequency domain spectral analysis.Formula (6) is transformed, then obtains concentration formula as the formula (7) about solution to be measured:

${\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=\frac{\ln {I_1}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;}-{{\ln I}_2}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;}-{{\ln I}_1}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;\&prime;}+{{\ln I}_2}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;\&prime;}}{\ln {I_2}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;\&prime;}-{{\ln I}_1}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;\&prime;}+{{\ln I}_1}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;}-\ln {I_2}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;}}\&CenterDot;C_2---\left(7\right)$

By formula (7) as can be known, the current concentration C of solution to be measured ₁Only and I ₁', I ₂', I ₁", I ₂", ε ₂', ε ₁', ε ₂", ε ₁", C ₂This Several Parameters is relevant, and with stable disturbance quantity ε _A, c _A, L _A, ε _B, c _B, L _BAnd with emission light light intensity I ₀Deng irrelevant,, realize long-term, continuous detecting to strength of fluid so the optical detecting method of monitoring liquid concentration of the present invention can successfully be eliminated the influence of stable disturbance quantity to detecting.As long as obtain I ₁', I ₂', I ₁", I ₂", ε ₂', ε ₁', ε ₂", ε ₁", C ₂, then can calculate the current concentration C of solution to be measured according to formula (7) ₁

Further, be that example specifies the course of work of the present invention with pick-up unit shown in Figure 2.

As shown in Figure 2, quill 1 is a tubular structure, and first plunger 2 and second plunger, 2 ' part place in the quill 1.The external diameter of the internal diameter of quill 1 and first plunger 2 and second plunger 2 ' is complementary, so that first plunger 2 and second plunger 2 ' can form motive seal with quill 1 respectively by zero RunddichtringO, and between quill 1 and first plunger 2 and second plunger 2 ', surround a fixedly cavity volume.

Sealing and fixing has printing opacity camera lens 7 in the quill 1, and make first plunger 2 and second plunger 2 ' lay respectively at the both sides of printing opacity camera lens 7, thereby the fixedly cavity volume that surrounds between quill 1 and first plunger 2 and second plunger 2 ' is divided into two independent cavity volumes of isolating mutually, solution cavity 5 promptly to be measured and reference solution chamber 9.The goggles that printing opacity camera lens 7 can adopt organic glass, general industry glass or tempered glass material etc. to make.

First plunger 2 and second plunger 2 ' are the non-movable piston of two same structures, are inner column hollow-core construction.Each sealing and fixing has a plunger camera lens 4 in the cavity of an end of first plunger 2 and second plunger 2 '.Form solution cavity 9 to be measured between the inner face of the plunger camera lens of formation reference solution chamber 5, the second plungers 2 ' and the printing opacity camera lens 7 between the inner face of the plunger camera lens 4 of first plunger 2 and the printing opacity camera lens 7; Be provided with liquid inlet and outlet 6 to be measured and reference solution inlet and outlet 8 on the wall of quill 1, solution inlet and outlet 6 to be measured is communicated with solution cavity 5 to be measured, and reference solution inlet and outlet 8 is communicated with reference solution chamber 9.

The central axes of two plunger camera lenses in first plunger 2 and second plunger 2 ' can be all by another plunger camera lens outgoing after one of them plunger camera lens incident to guarantee directional light.

The goggles that plunger camera lens 4 can adopt light transmissive materials such as organic glass, general industry glass or tempered glass material to make is so that it is parallel by plunger camera lens 4 to detect the parallel luminous energy of usefulness.As shown in Figure 1, plunger camera lens 4 can use and press nut 14 to be fixed on the inwall of first plunger 2 and second plunger 2 '.Press nut 14 to be shaped on external thread so that its inner thread with first plunger 2 and second plunger 2 ' is linked together, make plunger camera lens 4 simple installation, operate easily.Press nut 14 plunger camera lens 4 can be fixedly mounted on the end of the inner (i.e. an end of close printing opacity camera lens 7) of first plunger 2 and second plunger 2 ' by using, thereby the minimum light path possibility that makes solution to be measured and reference solution is near zero, increase the detection dirigibility of this pick-up unit of the present invention thus, increase the measurable range of solution concentration to be measured.Certainly, if the plunger camera lens of this pick-up unit is in the end of an end of the close printing opacity camera lens 7 of first plunger 2 and second plunger 2 ', and the continuous monitoring to the concentration of solution to be measured also can be realized in other positions that are positioned at first plunger 2 and second plunger 2 '.It is pointed out that to guaranteeing that the plunger camera lens can printing opacity press nut 14 that a central through hole 15 is arranged, this central through hole should be enough greatly to guarantee that light path is unimpeded between two plunger camera lenses 4.

The outer end of first plunger 2 and second plunger 2 ' (promptly away from that end of the printing opacity camera lens 7) is fixedly connected with hold-down support 12 respectively, and the light path between the plunger camera lens 4 of the plunger camera lens 4 of first plunger 2 and second plunger 2 ' is fixed.Quill 1, first plunger, 2 second plungers 2 ' and printing opacity camera lens 7 are formed synchronous backward with amplitude variable light path mechanism.

The length of quill 1 is more than the twice of the distance between the plunger camera lens of the plunger camera lens of first plunger 2 and second plunger 2 ', with the inner of guaranteeing first plunger 2 and second plunger 2 ' when quill 1 moves all the time some in quill 1 inside, thereby avoid first plunger 2, second plunger 2 ' and quill 1 disengaging.

As a kind of embodiment of solutions employed concentration detection apparatus of the present invention, can in the cavity of first plunger 2, be provided with directional light generator 3, the outer face of the plunger camera lens in this directional light generator 3 and first plunger 2 is relative; Be provided with optical receiver 3 ' in the cavity of second plunger 2 ', the outer face of the plunger camera lens in optical receiver 3 ' and second plunger 2 ' is relative.As the another kind of embodiment of solutions employed concentration detection apparatus of the present invention, also directional light generator 3 can be arranged in the cavity of second plunger 2 ', make the outer face of the plunger camera lens in directional light generator 3 and second plunger 2 ' relative; Simultaneously, optical receiver 3 ' is placed in the cavity of first plunger 2, and make the outer face of the plunger camera lens in optical receiver 3 ' and first plunger 2 relative.The effect of directional light generator 3 is to satisfy the detection to solution concentration to solution cavity 5 to be measured or reference solution chamber 9 emitting parallel lights, and make light pass solution to be measured, printing opacity camera lens 7 and reference solution, thereby being detected by solution to be measured and reference solution, optical receiver 3 ' absorbs light intensity afterwards.

Certainly, above-mentioned solution concentration pick-up unit can carry directional light generator 3 and optical receiver 3 ', as long as when using apparatus of the present invention, directional light generator 3 and optical receiver 3 ' are respectively installed in the cavity of first plunger 2 of apparatus of the present invention and second plunger 2 ', and make relative the getting final product in outer face of the plunger camera lens in directional light generator 3 and optical receiver 3 ' and the corresponding plunger.

Directional light generator 3 shown in Figure 2 is a collimating mirror, and collimating mirror is connected with the optical generator (not shown) by optical fiber can produce directional light.Optical receiver 3 ' also can be collimating mirror, and this collimating mirror is connected the light intensity that can be used for detecting emergent light by optical fiber with the optical receiver (not shown).This concentration detection apparatus is introduced detection light source and is derived ease for maintenance and the reusability that emergent light can improve device by optical fiber.

As the preferred implementation of the used concentration detection apparatus of the present invention, this device also is equipped with stepper motor 10, and the output shaft of stepper motor 10 is connected with and drives screw mandrel 11.In addition, the middle part of quill 1 web member 13 that has been fixedly connected, driving screw mandrel 11 and web member 13 moves by screw thread and cooperates, drive when making stepper motor 10 work and drive screw mandrel 11 rotations, and then by driving screw mandrel 11 by thread belt part 13 motions that are dynamically connected, drive quill 1 by web member 13 again and move vertically, thereby make printing opacity camera lens 7 move the volume size that changes solution cavity 5 to be measured and reference solution chamber 9.Because the total measurement (volume) in solution cavity 5 to be measured and reference solution chamber 9 is constant, therefore the volume-variation in solution cavity 5 to be measured and reference solution chamber 9 has the feature of synchronous backward with amplitude.

When using the inventive method that the concentration of solution to be measured is detected, concrete steps are as follows:

(1) according to the absorptivity typical curve of solution to be measured and reference solution, select two different wave length λ ', λ ", described wavelength X ' and λ " meet the following conditions:

If respectively with ε ₁', ε ₂' expression solution to be measured and reference solution are in the absorptivity of wavelength X ' locate, respectively with ε ₁", ε ₂The absorptivity of " representing that solution to be measured and reference solution are in wavelength X " and locating, then ε ₁' ≠ ε ₂' and ε ₁" ≠ ε ₂".

(2) solution to be measured is injected solution cavity 5 to be measured, reference solution is injected reference solution chamber 9.

(3) light source and the pick-up unit of correct joint detection device, make to detect and enter collimating mirror in first plunger by optical fiber with light, through plunger camera lens and collimating mirror in the plunger camera lens in first plunger, solution to be measured, printing opacity camera lens 7, reference solution, second plunger, arrive photodetector through optical fiber more successively.

(4) selecting the wavelength of light source incident light is λ ', is recorded under this incident light the transmitted light intensity I of solution to be measured and reference solution ₁'.

(5) light source incident light wavelength is switched to λ ", be recorded in λ " under the wavelength incident light, the transmitted light intensity I of solution to be measured and reference solution ₁".

(6) control step motor 10 makes and drives quill 1 motion, thereby makes the light path of solution to be measured and reference solution produce a percent ripple, and total optical path is constant, waits for that solution to be measured and reference solution are steady.

(7) be recorded in λ " under the wavelength incident light, the transmitted light intensity I of pulsation back solution to be measured and reference solution ₂".

(8) the light source lambda1-wavelength is switched to λ ', be recorded under the λ ' wavelength incident light, the transmitted light intensity I of pulsation back solution to be measured and reference solution ₂'.

(9), therefore can obtain the current concentration value of solution to be measured by following formula because the volume-variation in solution cavity 5 to be measured and reference solution chamber 9 has the feature of synchronous backward with amplitude:

${\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=\frac{\ln {I_1}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;}-{{\ln I}_2}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;}-{{\ln I}_1}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;\&prime;}+{{\ln I}_2}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_2}^{\&prime;\&prime;}}{\ln {I_2}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;\&prime;}-{{\ln I}_1}^{\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;\&prime;}+{{\ln I}_1}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;}-\ln {I_2}^{\&prime;\&prime;}\&CenterDot;{{\mathrm{\&epsiv;}}_1}^{\&prime;}}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HSA00000093020100021.png"\; state="\{\{state\}\}">C</figure-callout>}}_2$

In the following formula, C ₁Be the concentration value of current solution to be measured, C ₂Concentration known value for reference solution.

By following formula as can be known, solution concentration to be measured is only relevant with reference solution concentration, and is irrelevant with other disturbing factors, as long as reference solution concentration is accurate, solution concentration then to be measured is just accurate, thereby can demarcate solution concentration to be measured by real-time online, realizes the long-term continuous monitoring to solution concentration to be measured.

Claims (3)

1. the optical detecting method of a long-term continuously monitoring liquid concentration is characterized in that may further comprise the steps:

(1), choose two different wave length λ ' and λ according to the absorptivity typical curve of solution to be measured and reference solution ", described wavelength X ' and λ " meet the following conditions:

If respectively with ε ₁', ε ₂' expression solution to be measured and reference solution are in the absorptivity of wavelength X ' locate, respectively with ε ₁", ε ₂The absorptivity of " representing that solution to be measured and reference solution are in wavelength X " and locating, then ε ₁' ≠ ε ₂' and ε ₁" ≠ ε ₂";

(2) with light transmission device fixedly the cavity volume of light path be separated into solution cavity to be measured and reference solution chamber, solution cavity to be measured and reference solution chamber are respectively equipped with inlet and outlet, and solution to be measured is injected solution cavity to be measured, and reference solution is injected the reference solution chamber;

(3) make the end incident of parallel rays, and pass solution to be measured, light transmission device and reference solution from the cavity volume of described fixedly light path, again from the other end outgoing of the cavity volume of described fixedly light path, record emergent light this moment wavelength X ' and λ " light intensity of locating is respectively with I ₁' and I ₁" expression;

(4) keeping described light to pass under the state of solution to be measured, light transmission device and reference solution, mobile light transmission device is to change the light path of solution to be measured and reference solution, keep the pressure of solution to be measured and reference solution constant simultaneously, record this moment emergent light wavelength X ' and λ " light intensity of locating is respectively with I ₂' and I ₂" expression;

(5) obtain the current concentration value of solution to be measured by following formula

$C_1=\frac{\ln I_1^{\&prime;\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_2^{\&prime;}-\ln I_2^{\&prime;\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_2^{\&prime;}-\ln I_1^{\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_2^{\&prime;\&prime;}+\ln I_2^{\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_2^{\&prime;\&prime;}}{\ln I_2^{\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_1^{\&prime;\&prime;}-\ln I_1^{\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_1^{\&prime;\&prime;}+\ln I_1^{\&prime;\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_1^{\&prime;}-\ln I_2^{\&prime;\&prime;}\&CenterDot;{\mathrm{\&epsiv;}}_1^{\&prime;}}\&CenterDot;C_2$

In the following formula, C ₁Be the current concentration value of solution to be measured, C ₂Concentration known value for reference solution.

2. the optical detecting method of long-term continuously monitoring liquid concentration according to claim 1 is characterized in that:

(a) concentration by changing solution to be measured and correspondingly repeating said steps (3)～(5) are set up the relation curve of solution absorbency variable quantity to be measured and concentration;

(b) repeating said steps (3)～(4) obtain the current absorbance variable quantity of solution to be measured, and the relation curve of solution absorbency variable quantity to be measured that is obtained by step (a) and concentration obtains the current concentration of solution to be measured again.

3. the optical detecting method of long-term continuously monitoring liquid concentration according to claim 1 and 2, it is characterized in that: in step (4), solution cavity to be measured is communicated with by the solution to be measured of its inlet and outlet with the external world, and the reference solution chamber is communicated with by the reference solution of its inlet and outlet with the external world.

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