CN1122911A - Liquid concentration on-line measuring apparatus - Google Patents
Liquid concentration on-line measuring apparatus Download PDFInfo
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- CN1122911A CN1122911A CN 94117961 CN94117961A CN1122911A CN 1122911 A CN1122911 A CN 1122911A CN 94117961 CN94117961 CN 94117961 CN 94117961 A CN94117961 A CN 94117961A CN 1122911 A CN1122911 A CN 1122911A
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Abstract
The optical property measuring part of a measured liquid is a specially designed optical sensing head which includes a sealed cavity body and liquid prism jointly formed by two optical prisms transversely side by side set up at the central opening of the body bottom, collimated focussing lens group formed by lens, and laser set up in upper side of lens surface, and optical positions ensor fixed on two-dimension adjusting stand set up in upper side of lens surface. This invented on-line measuring appliance has simple structure, low cost, low requirement on light focussing system, large range of concentration measuring, good reliability and wide application.
Description
The invention belongs to a kind of liquid concentration measuring device, is a kind of law of refraction of light and novel optical sensitive device carries out on-line measurement to liquid refractive index and concentration instrument of utilizing.
Strength of fluid is a very important physical quantity., all need the concentration of liquid is measured etc. with each department and scientific research, national defence every field in commercial production such as chemical industry, pharmacy, light industry, food and drink, environmental protection.
To measure strength of fluid be one of method of using always by measuring liquid refractivity, because its measuring accuracy height, applied widely and extensively be used.Utilize in the device of refractometry strength of fluid existing, with few exceptions the (see figure 1) that designs according to the ATR Optical principle:
(glass for example, refractive index is n from optically denser medium when light
1) (liquid for example, refractive index is n to be mapped to optically thinner medium
2) time, refraction angle i
2Always greater than incident angle i
1, according to refraction law:
n
1Sin i
1=n
2Sin i
2Work as i
1Hour, have only the reflection of sub-fraction light intensity and most of anaclasis, and work as i
1Increase to a certain critical value i
1cThe time, refraction angle i
2c=90 °, promptly refracted ray is on the interphase of two media.If at this moment increase i again
1, then at optically thinner medium (n
2) side do not had refract light, all light press the reflection of light rule and are reflected, and promptly total reflection has taken place in light on the interface.At this moment incident angle i
1cBe called the cirtical angle of total reflection.
i
1c=sin
-1(n
2/ n
1Therefore) when a branch of light during with different angles incident, observe in reflected light one side, a tangible bright-dark cut ss will appear on the visual field, and this boundary line is just in time corresponding to cirtical angle of total reflection i
1cReflection ray (reflection angle is i
1c).Need seek this marginal position exactly based on refractometer or concentration meter that total reflection principle is made, so that determine cirtical angle of total reflection i
1c, again by known glass refraction n
1Calculate the refractive index n of testing liquid
2, and then calculate the concentration of liquid.Obviously, the difficult point of existing strength of fluid analyzer is to determine this marginal position, measure the optical characteristics of fluid to be measured thus, CN91209521.0 disclosed " camera method " for example, promptly adopt CCD (charge-coupled device) imageing sensor in reflected light one side " shooting ", obtain comprising the image of " face " of this bright-dark cut, again image transitions is become video pulse, send Computer Processing, calculate the concentration of liquid.But this device needs expensive optical image sensing device and complicated optics and Circuits System, and it is less to measure concentration range, is 0-25% only.
The objective of the invention is to deficiency at above-mentioned camera method strength of fluid instrument, provide a kind of simple in structure, need not image pickup optical system, liquid concentration on-line measuring apparatus that measurement range is bigger.
Liquid concentration on-line measuring apparatus of the present invention, comprise fluid to be measured optical characteristic measurement part, measured signal preamplifier, A/D analog to digital conversion interface, single-chip data is handled and the display part, it is characterized in that described fluid to be measured optical characteristic measurement partly is a custom-designed optical sensing head, this optical sensing head comprises a seal chamber and is arranged on common " liquid prism " that constitutes of horizontal two optical prisms side by side of seal chamber bottom centre opening part, one vertical chute is set on the cavity wall of the surface of a prism, set gradually three lens and semiconductor laser (LD) in this chute from the bottom to top in order to constitute the beam collimation focus lens group, a two-dimentional micropositioning stage is set in the chute that is provided with on the cavity wall above another prism surface, fix an optical sensitive device (PSD) on this micropositioning stage, this optical sensitive device has a sensitive surface, common cathode and two photocurrent output terminals are provided with a temp probe near the liquid prism place in cavity.
With laser instrument, collimation focus lens group and optical sensitive device are separately fixed at the interior appropriate location of vertical chute of two prisms top, by regulating laser instrument, the position of each lens and optical sensitive device, make laser beam be normally incident in the surface of a prism, its focus is fallen on the sensitive surface center line of PSD, when this optical sensing head inserts in the fluid to be measured, the laser scioptics group collimation that laser instrument sends focuses on the back and enters liquid prism by the prism below it, owing to liquid enters another prism to the refraction action of laser beam, and then the light of directive PSD and depart from the geometric center of the sensitive surface of PSD, to be irrelevance x change with the difference of fluid to be measured refractive index in its displacement, PSD converts this change in displacement to current signal, and sort signal is sent into prime amplifier.While is also sent into prime amplifier by the current signal of the reflection fluid to be measured temperature that temp probe detects, prime amplifier becomes voltage signal with photo-signal with the temperature current conversion of signals, and being transformed into digital signal by A/D analog to digital conversion interface, scm managing system just calculates strength of fluid and demonstrates measurement result according to these digital signals.
Laser instrument is selected visible light for use, so that observation is adjusted.Two lens in top in the lens combination are formed colimated light system, so that LD laser-beam divergence angle is reduced.The 3rd lens make collimated light beam focusing that focus is fallen on the PSD sensitive surface again.Laser instrument and three lens all are contained in the chute of prism surface top cavity, all can move up and down so that obtain required collimation focused beam.Optical prism will be selected the glass of refractive index greater than the fluid to be measured refractive index for use.Its drift angle and other size of two jiaos should make laser with on the face that liquid contacts total reflection can not take place in two prisms, so that maximally utilise luminous energy, after the aspect makes light by liquid prism again in addition the maximum angular resolution with variations in refractive index are arranged.Calculating shows that it is that the isosceles triangle prism at right angle just can meet the demands preferably that two prisms all adopt drift angle.Described optical sensitive device PSD is a kind of junction type photoelectric device, and that the present invention uses is one dimension PSD, and it has a sensitive surface, three electrodes, a common cathode and two photocurrent output terminals are when its sensitive surface of rayed, the photocurrent output terminal can be exported photocurrent, and its size is relevant with the illumination position.PSD is installed on the micro two-dimensional adjusting bracket, and this adjusting bracket is fixed in the chute of cavity.Therefore in fact can make three-dimensional regulation to the locus of PSD, this was very important in the debug phase, the center line that can guarantee the PSD sensitive surface simultaneously when calibration, allows the emergent ray of a certain standard solution just in time on how much mid points of directive PSD all the time in the plane that light and normal are formed.After debugging finished, then each movable part all need be fixed.Described prime amplifier is a two-level operating amplifier, all use one integrated for every grade, in the circuit of two fully symmetry, ultralow drift, ultralow offset voltage precision operational-amplifiers is arranged, make the two-way photocurrent suffered because the error that temperature drift etc. causes symmetry fully, cancel each other, improved measuring accuracy greatly.The AD1674 that described A/D analog to digital conversion interface can adopt the band sampling to keep can make two photo-signals and temperature signal think what synchronization recorded, has improved measuring accuracy.Described scm managing system can be 8031 single-chip microcomputers, and remaining circuit adopts existing common circuit.
Be further described below in conjunction with the structure and the effect thereof of accompanying drawing liquid concentration on-line measuring apparatus of the present invention.
Fig. 1 is the ATR Optical schematic diagram of existing concentration meter institute foundation.
Fig. 2 is an optical sensing head structural representation of the present invention.
Fig. 3 is an optical sensitive device PSD structural representation.
As shown in Figure 2, optical sensing head of the present invention, be one by seal chamber 1 with arrange At the horizontal optical prism 6 arranged side by side of seal chamber bottom centre opening part and the 7 common liquid that consist of The body prism, the laser that is sent by semiconductor laser 2 passes through the surface that is arranged on optical prism 6 Be normally incident in the surperficial 6-1 of prism 6 behind the lens 3 of 6-1 top, 4 and 5 collimation focusings, its What transmitted light entered liquid prism after the reflecting surface 6-2 of this prism total reflection advances light face (prism 6 exiting surface) 6-3, the exiting surface by liquid prism after the liquid prism refraction (is prism 7 Advance the light face) 7-3 penetrates and enters optical prism 7, and be all-trans through this prismatic reflection face 7-2 Be mapped to and reach surperficial 7-1, further reflect and enter and be arranged on this prism 7 surperficial 7-1 tops Be fixed on the optical sensitive device 9 on the two-dimensional adjustment frame 10. Enter optical sensitive device PSD when measuring light 8 When shining its sensitive surface 16, two outputs 18 of optical sensitive device PSD9 and 19 will export two Individual light stream I1And I2, its size is relevant with the displacement x between the PSD geometric center 17 with light spot energy center 20: I wherein0For being proportional to the total current of light source intensity.
I
0＝I
1＋I
2L is half of PSD sensitive surface total length. When light source intensity changes, I1、I
2Proportional variation, and displacement Change irrelevant with light intensity.
While I1、I
2Only relevant with the light spot energy center, therefore with the light spot shape relation Not quite, so can greatly reduce requirement to beam collimation and focusing.
By actual measurement I1And I2, can try to achieve displacement x. Structural parameters, PSD 9 at prism The position and after the position 14 of incident light vertical incidence determines, the refractive index n of fluid to be measured is just Set up well-determined relation with displacement x, by interface 6-3,7-3 and 7-1 are used light The law of refraction and the simple geometrical relationship correspondence table that can try to achieve x and n. Allow certain during debugging (pure water for example, to aim at PSD mid point 17 (logical for emergent ray in the time of n=1.3330) for one standard liquid Crossing adjustment micropositioning stage 10 makes single-chip microcomputer show I1＝I
2Obtain, then the secured adjusted frame). Measure The time, by actual measurement I1、I
2Namely can be regarded as to get x:x=(I1-I
2)L/(I
1＋I
2), L is that PSD is subjected to Light face length degree is partly tried to achieve testing liquid refractive index n, again basis according to the correspondence table of x-n again N and temperature t can be calculated the concentration value of liquid.
The present invention has following characteristics with existing CCD camera method concentration meter ratio:
1. owing to adopted optical sensitive device PSD, reduced image pickup optical system, optical texture and electronic circuit have all been simplified greatly, thereby reduced the complete machine cost as light sensor.
Since PSD only to light spot energy center sensitivity, thereby can ignore to the light source intensity variable effect, thereby improved measurement stability greatly, also further reduced the requirement of collimation Focused Optical system simultaneously.
3. because structural parameters and the resolution parameter characteristics of existing PSD can make the concentration range of measurement bigger.
4. adopt prism 6 and prism 7 to constitute liquid prism, constituted the light path catadioptric system again, make compact conformation with cavity 1.
5. use semiconductor laser as light source, it has the big and good characteristics of monochromaticity of light intensity, and the former can make luminous energy pass through liquid, makes existing total reflection method become transmission beam method, so that available PSD is as light sensor.The latter can avoid using optical filtering and achromatic optical system.
Below be example by a strength of fluid on-line determination instrument of concept of the present invention:
Semiconductor laser: the HLG711G type of Japanese HITACHI company, wavelength 0.67 μ m, peak power 5mw.
Lens 3:f=3mm, φ=6mm, plano-convex lens.
Lens 4, f=18mm, φ=6mm, plano-convex lens.
Lens 5, f=80mm, φ=10mm, biconvex lens.
Optical sensitive device PSD: the S3931 of Japanese HAMAMATSU company, resolution can reach 0.2 μ m, 2L=6mm.
Temp probe: AD590, sensitivity is 1 μ A/K.
Prime amplifier: secondary 0P207.
A/D A/D interface: AD1674
Single-chip microcomputer: 8031
The little invar of cavity 1 usefulness expansion coefficient processes.Prism 6 and 7 usefulness fluid sealants are bonded on the cavity 1.
It is 1.3330-1.4205 that present embodiment can get the refractometry scope, precision is 0.0002, sucrose solution concentration range when being equivalent to 20 ℃ is 0-50%, precision is 0.1%, if adopt long optical sensitive device, for example use S3932, measurement range also can improve greatly, can satisfy the on-line measurement requirement in the production runes such as sugaring, beverage, beer and many medicines fully.
Claims (2)
1. liquid concentration on-line measuring apparatus, comprise fluid to be measured optical characteristic measurement part, the prime amplifier of measured signal, A/D analog to digital conversion interface, single-chip data is handled and the display part, it is characterized in that described fluid to be measured optical characteristic measurement partly is a custom-designed optical sensing head, this optical sensing head comprises an annular seal space (1) and is arranged on horizontal two optical prisms (6) and (7) common " liquid prism " that constitutes side by side of seal chamber bottom centre opening part, one hard straight chute (1-1) is set on the top cavity wall of the surperficial 6-1 of prism (6), set gradually from the bottom to top in this chute in order to constitute the lens (5) of beam collimation focus lens group, (4) and (3) and semiconductor laser (LD) (2), one hard straight runner (11) is set on the top cavity wall of the surperficial 7-1 of another prism (7), a two-dimentional micropositioning stage (10) is set in this chute, on this micropositioning stage, fix an optical sensitive device (PSD), described optical sensitive device has a sensitive surface (16), near the liquid prism place one temp probe (13) is set in common cathode (15) and two photocurrent output terminals (18) and (19), cavity.
2. liquid concentration on-line measuring apparatus as claimed in claim 1 is characterized in that described prism (6) and prism (7) are that a drift angle is the isosceles right triangle prism at right angle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94117961 CN1122911A (en) | 1994-11-11 | 1994-11-11 | Liquid concentration on-line measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 94117961 CN1122911A (en) | 1994-11-11 | 1994-11-11 | Liquid concentration on-line measuring apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1122911A true CN1122911A (en) | 1996-05-22 |
Family
ID=5038596
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 94117961 Pending CN1122911A (en) | 1994-11-11 | 1994-11-11 | Liquid concentration on-line measuring apparatus |
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|---|---|
| CN (1) | CN1122911A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1845365A1 (en) * | 2005-02-02 | 2007-10-17 | Matsushita Electric Industrial Co., Ltd. | Optical element and optical measurement device using the same |
| CN100350262C (en) * | 2005-02-06 | 2007-11-21 | 重庆工学院 | On-line testing system for capacity of vehicle lead-acid battery |
| CN100580423C (en) * | 2003-04-28 | 2010-01-13 | 阿尔卑斯电气株式会社 | Concentration measuring optical member and concentraton measuring unit and fuel cell |
| CN101400987B (en) * | 2006-03-16 | 2011-04-13 | 仓敷纺绩株式会社 | Total reflection attenuation optical probe and aqueous solution spectrometric device |
| CN103630514A (en) * | 2013-11-05 | 2014-03-12 | 杭州陆恒生物科技有限公司 | Multifunctional digital display refractometer |
| CN106908388A (en) * | 2017-03-16 | 2017-06-30 | 亿信标准认证集团有限公司 | Strength of fluid standard authentication detecting system on plant chimney stalk discharge |
| CN108489936A (en) * | 2018-04-08 | 2018-09-04 | 吉林省富生医疗器械有限公司 | A kind of domestic type cystatin C concentration Quick testing instrument and its assay method |
| CN108593599A (en) * | 2018-05-29 | 2018-09-28 | 莆田市烛火信息技术有限公司 | A kind of brine for kitchen use, syrup concentration measure Intelligent water cup |
| CN110514624A (en) * | 2018-05-22 | 2019-11-29 | 泰科电子(上海)有限公司 | Concentration detection apparatus, concentration measurement and control device and solar water heater |
| CN112147082A (en) * | 2020-09-24 | 2020-12-29 | 杭州春来科技有限公司 | Vehicle-mounted urea monitoring device and monitoring method |
-
1994
- 1994-11-11 CN CN 94117961 patent/CN1122911A/en active Pending
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100580423C (en) * | 2003-04-28 | 2010-01-13 | 阿尔卑斯电气株式会社 | Concentration measuring optical member and concentraton measuring unit and fuel cell |
| EP1845365A1 (en) * | 2005-02-02 | 2007-10-17 | Matsushita Electric Industrial Co., Ltd. | Optical element and optical measurement device using the same |
| EP1845365A4 (en) * | 2005-02-02 | 2009-07-01 | Panasonic Corp | Optical element and optical measurement device using the same |
| US7598483B2 (en) | 2005-02-02 | 2009-10-06 | Panasonic Corporation | Optical element and optical measurement device using the optical element |
| CN100350262C (en) * | 2005-02-06 | 2007-11-21 | 重庆工学院 | On-line testing system for capacity of vehicle lead-acid battery |
| CN101400987B (en) * | 2006-03-16 | 2011-04-13 | 仓敷纺绩株式会社 | Total reflection attenuation optical probe and aqueous solution spectrometric device |
| CN103630514A (en) * | 2013-11-05 | 2014-03-12 | 杭州陆恒生物科技有限公司 | Multifunctional digital display refractometer |
| CN103630514B (en) * | 2013-11-05 | 2016-09-07 | 杭州陆恒生物科技有限公司 | A kind of Multifunctional digital display refractometer |
| CN106908388A (en) * | 2017-03-16 | 2017-06-30 | 亿信标准认证集团有限公司 | Strength of fluid standard authentication detecting system on plant chimney stalk discharge |
| CN108489936A (en) * | 2018-04-08 | 2018-09-04 | 吉林省富生医疗器械有限公司 | A kind of domestic type cystatin C concentration Quick testing instrument and its assay method |
| CN108489936B (en) * | 2018-04-08 | 2024-03-19 | 吉林省富生医疗器械有限公司 | Household cystatin C concentration rapid tester and testing method thereof |
| CN110514624A (en) * | 2018-05-22 | 2019-11-29 | 泰科电子(上海)有限公司 | Concentration detection apparatus, concentration measurement and control device and solar water heater |
| CN108593599A (en) * | 2018-05-29 | 2018-09-28 | 莆田市烛火信息技术有限公司 | A kind of brine for kitchen use, syrup concentration measure Intelligent water cup |
| CN112147082A (en) * | 2020-09-24 | 2020-12-29 | 杭州春来科技有限公司 | Vehicle-mounted urea monitoring device and monitoring method |
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