CN1106138A - In-line monitoring method of gas turbidity and dusty concentration and its monitor - Google Patents
In-line monitoring method of gas turbidity and dusty concentration and its monitor Download PDFInfo
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- CN1106138A CN1106138A CN 94108036 CN94108036A CN1106138A CN 1106138 A CN1106138 A CN 1106138A CN 94108036 CN94108036 CN 94108036 CN 94108036 A CN94108036 A CN 94108036A CN 1106138 A CN1106138 A CN 1106138A
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Abstract
The method and apparatus for in-line monitoring of gas turbidity and dust concentration mainly features integrating laser, optical fibre, phase locking and microcomputer in a whole, implementing correlative measurement by single-way dual-beam two-terminal system structure with transreceiver separately arranged and coupling transmission of reference light on optical fibre, dust-proof sleeve barrel of optical fibre coupling head for high correctness, use of light-switching disk for measured and reference light beams using a single detector and processing system, use of semiconductor laser for long service life, and using phase-locking and 8098 singl-chip processor for analog and digital signal processing.
Description
The invention belongs to fields of measurement, be specifically related to a kind ofly make light source, method and monitor thereof that the turbidity or the contained dust concentration of all gases are carried out real time on-line monitoring with semiconductor laser diode.
At present, the method for measurement gas dustiness is divided into two big classes: sedimentation and non-sedimentation substantially both at home and abroad.Though sedimentation has the advantage of the mass concentration of dust in the direct measurement gas, but since it can not be automatically, continuous coverage, especially can't realize the on-line monitoring of pollution source and complex operation, measuring error is big, far the requirement of incompatibility current environment pollution Monitoring.Non-sedimentation monitoring means, development in recent years are than piece, and the non-contact on-line monitor that utilizes optical principle to make in non-sedimentation is widely-used abroad.The monitoring method of this quasi-instrument mainly is divided into two kinds of optical transmission method and light scattering methods, the design feature of many this quasi-instruments has nothing in common with each other both at home and abroad, influence all multifactor of measuring accuracy in order to overcome, the level and the effect of the technical measures that the raising monitoring accuracy is taked are different mutually, integrate and see, this type of existing commercialization instrument all remains further perfect, what have exists tangible deficiency or defective, for example, how to eliminate effectively because the measuring error that the window ara ash fouling causes, this is both at home and abroad with the ubiquitous problem of quasi-instrument, also is one of key issue that influences such tester measuring accuracy.D-R216 turbidimeter as German DURAG company produces though added fan blower in measuring system, carries out air blast to the window face and isolates, and the slow dust stratification of not stopping the window face pollutes, and still has the measuring error that causes thus in the use.M400 type produced in USA and DYNATRON1100 type turbidimeter though increased window surface state detector, because the pollution of detector photosurface does not take measures to overcome, also can not be realized measuring error is compensated automatically effectively.JFN-2 type dust concentration meter as The Inst. of Electric Power Testing ﹠ Research, Inner Mongolia, make light source with the He-Ne laser instrument, adopt two light sources, monochromatic light journey to examining system, automatically the error that causes of compensatory light, voltage fluctuation and electronic devices and components performance change, but the error that the window surface pollution causes can't compensate, and be not suitable for vibrating bigger occasion, moreover it is shorter to make light source life with the He-Ne laser instrument.
The purpose of this invention is to provide a kind of laser technology, optical fiber technology, phaselock technique and microcomputer technology that collects the advanced person is one, can compensate automatically because the beam drift that window ara ash, supply voltage and intensity of light source fluctuation, detector and electronic devices and components performance change, flue vibration and distortion and Smoke Turbulent Effect cause and expand the error that multiple factor such as spot causes is monitored the on-line monitoring method and the monitor thereof of gas turbidity and dust content in real time.
This on-line monitoring method will be divided into from the single light beam of laser instrument in a side of tested gas when measuring to be measured and with reference to two-beam, and transmitting terminal and receiving end split the both sides at tested gas, this structure is called twin-beam, monochromatic light journey double-end measurement system, beam modulation is become the alternation light of required frequency by chopper wheel, from the transmitted light of first beam divider and reflected light under the effect of cutting CD that a synchronous motor drives behind second beam divider, its two bundles reflected light is periodically alternately incided on the photoelectric commutator that places tested gas one side, as reference light, note is made I0 and I0 ' respectively, two bundle transmitted lights from second beam divider, a branch ofly pass tested gas as measuring light, a branch of through the optical fiber coupled transfer as reference light, what measuring light and reference light replaced incides on the photoelectric commutator that places tested another survey of gas, note is made Ir and Ir ' respectively, make the light intensity that incides on the photoelectric commutator ascending and descending variation occur by same period, after analog signal processing, form the trapezoidal wave of certain amplitude, by the data handling system collection and calculate the transmitance T=Ir/I0=e of tested gas according to Lambert-Beer's law
-acL, and then the turbidity that calculates tested gas is Q=1-T, the concentration of tested gas is C=Ln(1/T)/(α L) (in formula: the attenuation coefficient of α-tested gas, the concentration of the tested gas of C-, the thickness of the tested gas of L-).
This on-line monitoring instrument comprises light path and photo-translating system, air cleaning system, the analog signal processing system, data handling system, light path and photo-translating system comprise laser instrument 1, the transmitting terminal 2 of light path, the receiving end 7 of light path, photoelectric commutator 4,8, fiber coupler 5,6, Transmission Fibers 25, air cleaning system comprises air purifying room 10,11, air cleaner 12,13, the analog signal processing system comprises prime amplifier 3,9, power supply 14, terminal box 15, analogy signal processing unit 16, data handling system comprises A/D converter 17, data processing unit 18, nixie display 19, mini-printer 20, analog quantity indicator 21, analog quantity output 22, sound, light warning device 23 is formed, its decontamination chamber 10, the both sides that 11 symmetries are placed on tested gas respectively with air cleaner 12,13 connect, the light beam that laser instrument 1 sends enters the transmitting terminal 2 of light path system, the light signal part that the transmitting terminal 2 of light path system sends is through the decontamination chamber 10, tested gas, the receiving end 7 of decontamination chamber's 11 directive light path systems, a part is through fiber coupler 5, optical fiber 25, the receiving end 7 of fiber coupler 6 transmission directive light path systems, its light signal replaces enters photoelectric commutator 8, the ac signal of photoelectric commutator 8 outputs enters prime amplifier 9, a part is directly through photoelectric commutator 4 outputs, its electric signal enters prime amplifier 3, prime amplifier 3, the signal of 9 outputs connects with analogy signal processing unit 16 through terminal box 15 respectively, and the output terminal of simulating signal enters data processing unit through A/D converter 17 to carry out data processing and demonstration and print measurement result.
Light path transmitting terminal 2 comprises plane total reflective mirror 27; 30; 33; 34; first beam divider 29; second beam divider 36; convergent lens 35; chopper wheel 28; cut CD 32; protection window 37; the light path receiving end comprises protection window 38; convergent lens 39; the light of being launched by laser instrument 1 reflects through total reflective mirror 27; reflected light is through chopper wheel 28; first beam divider 29 is divided into transmitted light and reflected light; wherein transmitted light is through catoptron 30 with cut CD 32 directives second beam divider 36; a part is made Ir for the transmitted light note; a part is made Io for the reflected light note; transmitted light penetrates tested gas through transmitting terminal protection window 37 and enters receiving end; incide on the photoelectric commutator 8 through receiving end protection window 38 and convergent lens 39; reflected light incides on the detector 4 through convergent lens 35; from the reflected light of first beam divider 29 through cutting CD 32; total reflective mirror 34; 33 directives, second beam divider 36; a part is made Ir ' for the transmitted light note; a part is made Io ' for the reflected light note; transmitted light enters fiber coupler 5 through protection window 37 and is transferred to receiving end again through the fiber coupler 6 of receiving end through optical cable 25; protection window 38 and convergent lens 39 incide on the photoelectric commutator 8; reflected light incides on the photoelectric commutator 4 through convergent lens 35; photoelectric commutator 4 connects with prime amplifier 3; photoelectric commutator 8 connects with prime amplifier 9; have an aperture on the CD cutting, with the photoelectrical coupler assembling and positioning.
Its analogy signal processing unit is formed phase-locked amplification channel by AC amplifier AC1, phase-sensitive detector (PSD) PSD1, low-pass filter LPF1, direct current amplifier DC1, AC amplifier AC2, phase sensitive amplifier PSD2, low-pass filter LPF2, direct current amplifier DC2 form the synchronous demodulation passage, phase shifter one terminates between AC amplifier AC2 and the phase sensitive amplifier PSD2, and the other end connects with phase sensitive amplifier PSD1.
The head of fiber coupler installs dustproof sleeve 40 additional.Its laser instrument adopts semiconductor laser.
This monitoring method and monitor thereof have the following advantages:
1. owing to optical fiber of cross-over connection between the protection window at sending and receiving two ends; a branch of reference light is carried out coupled transfer, constitute single light source, monochromatic light journey, double-beam system, realized measurement of correlation; effectively overcome the measuring error that the window ara ash is caused, improved measuring accuracy.
Realize that measurement of correlation principle and evaluation formula are as follows:
Light path in the system is divided into as shown in Figure 4 three sections of L1, L2, L3, if the light intensity of measuring light and each segmentation place of reference light is respectively I0, Ir1, Ir2, Ir3 and I0 ', Ir1 ', Ir2 ', Ir3 ', according to Lambert-Beer's law, the transmittance of each light path section is expressed as respectively:
Measure light path: T1=Ir1/I0=e
-β 1L1
T2＝Ir2/Ir1＝e
-β2·L2
T3＝Ir3/Ir2＝e
-β3·L3
Reference path: T1 '=Ir1 '/I0 '=e
-β 1 ' L1 '
T2′＝Ir2′/Ir1′＝e
-β2′·L2′
T3′＝Ir3′/Ir2′＝e
-β3′·L3′
Total transmitance of two light paths is respectively:
T＝T1·T2·T3＝Ir3/I0
＝e
-β1·L1·e
-β2·L2·e
-β3·L3（1）
T′＝T1′·T2′·T3′＝Ir3′/I0′
＝e
-β1′·L1′·e
-β2′·L2′·e
-β3′·L3′（2）
Two sections decay that light path caused are from dust stratification on window and the window and lens 39 to two-beam through L1, L3.And window is a uniform thickness, and the dust stratification on the window is to be overflow to pollute by random flying dust to cause, and dust stratification distributes can regard uniform as, two-beam is transferred to the uniform thickness position at the incidence point of lens, remainder on these two sections light paths is in the seal cavity of instrument, and optical attenuation is not had effect, so:
β1·L1＝β1′·L1′，β3·L3＝β3′·L3′，
Therefore (1)/(2) are:
（Ir3·I0′）/（I0·Ir3′）＝e
-β2·L2/e
-β2′·L2′
β 2 ' L2 ' is a known number in the formula, so e
-β 2 ' L2 'Be a constant, represent, be called the coupling coefficient of Transmission Fibers, that is: with K
T cigarette=T2=Ir2/Ir1=e
-β 2L2=(Ir3I0 ')/(I0Ir3 ') K (3)
The turbidity of flue gas is the Q=1-T cigarette
＝1- (Ir3·I0′)/(Ir3′·I0) ·K（4）
The mass concentration of C-flue gas
That is: e
-α CL2=(Ir3I0 ')/(I0Ir3 ') K
These formula both sides mass concentration expression formula that conversion draws flue gas of taking the logarithm is:
C cigarette=Ln (I0Ir3 ')/(I0 ' Ir3K)/(α L7)
(size of α depends on the characteristic of dust-laden particulate in the formula (5), and its characteristic depends on the operating mode of coal, boiler and fly-ash separator etc.For single coal or the fixing mixing coal of reference, under the basicly stable prerequisite of boiler and fly-ash separator operating mode, α can be considered a constant, its value is obtained by demarcation), the result who is derived by above-mentioned evaluation formula finds out realization double light path measurement of correlation, can eliminate the measuring error that the window surface pollution causes automatically, also significantly reduce the maintenance times of instrument simultaneously.
2. because the lateral surface and the fibre-coupled mirrors of window are in the same space, dusty gas is all exposed, so fibre-coupled mirrors is polluted equally in the time of to the window surface pollution, therefore install half closed dust sleeve additional in the front portion of optical fiber coupling head, tube length and internal diameter design by a certain percentage, overcome the dust stratification pollution problem of fibre-coupled mirrors effectively, guaranteed the effect and the accuracy of measurement of correlation.
3. owing to adopt semiconductor laser, the divergence of light beam is little, and light intensity is concentrated, and help photoelectric commutator and receive entirely, and power consumption is low, and thermal value is little, and the life-span is long.Light path system is designed to the one way structure that sending and receiving split, thereby is easy to guarantee the full raising monitoring accuracy that receives, and is lower to the output power and the divergence requirement of light source simultaneously, is convenient to installation, debugging and maintenance.
4. adopt synchronous motor to drive in the light path and cut CD, make measuring beam and reference beam automatically switch, export in succession, realized that two optical path signals share a photoelectric commutator and same signal processing system, through normalized, effectively overcome because the photoelectric commutator changes of properties, aging, the temperature of electronic component are floated the measuring error that supply voltage and light source fluctuation etc. causes.
5. the convergent lens of receiving end is designed to enough greatly, guarantees that light receives entirely, has overcome effectively because the light beam that flue vibration, deformation and Smoke Turbulent Effect cause expands the measuring error that factors such as spot and drift cause.
6. because entering of replacing of measuring beam and reference beam and throw off the measurement zone and the Resistance of cutting CD, make the light intensity that is transmitted on the photoelectric commutator ascending and descending variation occur by same period, the electric signal of consequent big or small alternate is when lock-in amplifier is handled, because the influence of the time constant of low-pass filter, make output waveform form the edge, front and back of certain width, when avoiding computer data acquisition, sampling causes error on the edge, have a through hole on the certain position of CD cutting, with the photoelectrical coupler assembling and positioning, cutting CD whenever circles and just provides a synchronous acquisition signal, guarantee the accuracy of synchronous data collection, avoided having improved measuring accuracy owing to cut the accumulated error that the cd-rom drive motor rotary speed unstabilization causes.
7. utilize flue negative pressure, saved fan blower in the device, use air cleaner, by the flue inside and outside differential pressure, form the nature air draught and isolate, the protection window is avoided smoke pollution, and the size of intake is regulated by the air door that is contained in air cleaner inflow point.
8. this instrument adopts the single-frequency lock-in amplifier to carry out analog signal processing, has improved the monitoring sensitivity and the resolving power of instrument greatly.
9. adopt 8098 single-chip microcomputers to carry out data processing and control, improved the ratio of performance to price of instrument.
10. this instrument can adapt to abominable on-the-spot working environments such as ash (powder) dirt, vibration, high temperature, can be widely used in the continuous monitoring of flue gas turbidity, concentration or the surrounding air dustiness of industrial sectors such as thermal power plant, metallurgy, chemical industry, cement, weaving.Also can make portablely according to customer requirements, go the rounds to measure.Therefore, this instrument is pollution source on-line monitoring or the touring desirable instrument that detects, and also is to connect with CPU (central processing unit) to constitute closed loop border control system, realizes the key equipment of dedusting energy-saving.In addition, take certain measure, this instrument also can be installed on the walling of flue of various Industrial Boiler fly-ash separators porch, has realized that on the one hand the real-time continuous of efficiency of dust collection is measured, and can realize the continuous monitoring of boiler operatiopn operating mode again and provides boiler combustion self-adjusting feedback signal.
The invention will be further described in conjunction with following accompanying drawing:
Fig. 1 is the structured flowchart of this monitor
Fig. 2 is the light path and the photo-translating system figure of monitor
Fig. 3 is photosignal waveform figure
Fig. 4 is the fiber coupler synoptic diagram
Fig. 5 is a monochromatic light journey double-beam system synoptic diagram
Fig. 6 is the analogue signal processor structured flowchart
Fig. 7 is the analogue signal processor output waveform figure
Fig. 8 is the computing machine main program block diagram
Fig. 9 is the computer sub block diagram
Figure 10 is the front panel synoptic diagram of secondary instrument
Figure 11 is the rear panel synoptic diagram of secondary instrument
Figure 12 is the data handling system structured flowchart
Among the figure:
1-laser instrument 2-light path transmitting terminal
7-light path receiving end 4,8-photoelectric commutator
5,6-fiber coupler 10,11-air purifying room
12,13-air cleaner 3,9-prime amplifier
14-power supply 15-terminal box
16-analogy signal processing unit 17-A/D converter
18-data processing unit 19-nixie display
20-mini-printer 21-analog quantity indicator
The output of 22-analog quantity (0～5V) 23-sound, light warning device
24-connecting flange 25-Transmission Fibers
26-walling of flue 27,30,33,34-plane total reflective mirror
The 29-first beam divider 36-second beam divider
35,39-convergent lens 28-chopper wheel
32-cuts CD 37,38-protects window
The 31-photoelectrical coupler 40-sleeve that prevents dust
41-optical fiber coupling head 42-transmission cable
AC1, AC2-AC amplifier DC1, DC2-direct current amplifier
PSD1, PSD2-phase-sensitive detector (PSD) LPF1, LPF2-low-pass filter
φ-phase shifter
～ ～ ～ ～
Vr, Vr '-ac voltage measurement signal Vo, Vo '-alternating voltage reference signal
- - - -
Vr, Vr '-dc voltage measurement signal Vo, Vo '-DC voltage reference signal
52-turbidity value pilot lamp 53-concentration value pilot lamp
54-voltage table 55-reometer
56-16 figure place keyboard 57-four bit function keys
58-power switch 59-voltage indication switch
60-functional select switch 62-alarm lamp
63-synchronous acquisition pilot lamp 64-supply socket
65-fuse base 67-input interface (connecting primary instrument)
70-synchronous acquisition circuit 71-shaping circuit
72-8098 single-chip microcomputer 73-I/0 interface (1)
74-power amplifier 75-storer
76-I/0 interface (2) 77-photoisolator
The frame of broken lines I is the transmitting terminal of monitor among Fig. 1; the frame of broken lines II is the receiving end of monitor; the frame of broken lines III is the secondary instrument of monitor; an aperture is respectively opened in two pairs of surveys on the straight length of tested exhaust gases passes; the centre at tested exhaust gases passes is opened in this hole; straight length after requiring the preceding straight length of gaging hole greater than gaging hole; be welded on two ring flanges that process in advance on the aperture respectively; transmitting terminal and receiving end with air cleaner and apparatus measures head connects successively then; pad adds the disposable orientation that regulates measuring head of sheet metal on the different azimuth between two flanges; light path is aimed at; the fiber optic loop that to be furnished with metal hose protection around and the vertical gas pass cabling; the optical fiber two ends are connected in respectively on transmitting terminal and the receiving end; size according to negative pressure in the flue; regulate the throttle opening of air cleaner, connect power supply; terminal box; secondary instrument, power supply are alternating current 220V.
Be the transmitting terminal of light path system in the frame of broken lines of the left side among Fig. 2, in the frame of broken lines of the right is the receiving end of light path system, the synchronous motor that adopts per second 1 to change in the light path drives cuts CD, make that measuring beam and reference beam automatically switch, output in succession, realized that two light paths share a detector and same signal processing system.
The photosignal waveform figure of A～H8 point has been shown, wherein I among Fig. 3
AThe photosignal waveform figure of oscillogram for adopting semiconductor laser 1 to send, I
BOscillogram is the photosignal waveform figure after modulating through chopper wheel 28, I
C, I
D, I
E, I
FOscillogram is the oscillogram after process is cut CD, I
GBe the oscillogram of light signal on detector 9, I
HBe the oscillogram of light signal on detector 3.
Fig. 4 shows the fiber coupler synoptic diagram, installs a semiclosed dustproof sleeve additional in the front portion of optical fiber coupling head, and tube length and internal diameter design by a certain percentage.
Fig. 5 shows monochromatic light journey double-beam system synoptic diagram, has derived the relevant evaluation formula of this monitor with reference to this figure.
Fig. 6 forms phase-locked amplification channel by AC amplifier AC1, phase-sensitive detector (PSD) PSD1, low-pass filter LPF1, direct current amplifier DC1, AC amplifier AC2, phase sensitive amplifier PSD2, low-pass filter LPF2, direct current amplifier DC2 form the synchronous demodulation passage, phase shifter one terminates between AC amplifier AC2 and the phase sensitive amplifier PSD2, and the other end connects with phase sensitive amplifier PSDi.AC amplifier AC, phase-sensitive detector (PSD) PSD, low-pass filter LPF, direct current amplifier DC are custom circuit.
Fig. 7 shows the analogue signal processor output waveform figure, produce its amplitude note of a pulse by photoelectrical coupler 1 second by the aperture of cutting CD and make Vs, make computing machine begin synchronous acquisition voltage signal Vr, V0, Vr ', V0 ' and carry out the A/D conversion as the external interrupt signal of computing machine.
57 is 4 function keys among Figure 10, comprises reset key Reset, upturning key Last, downturning key Next, execute key Exec, and 60 is function selecting key, have 0～90 state, the computing of 0 coupling coefficient of optical fiber when being static debugging, 1 is the turbidity computing, 2 is the concentration computing, and other state is standby.
Figure 12 shows the data handling system structured flowchart, produce 1 pulse signal by the photoelectrical coupler in the light path system 1 second by the aperture of cutting CD, be connected with single-chip microcomputer through synchronous acquisition circuit 70, shaping circuit 71, give pulse signal Vs of single-chip microcomputer 1 second, voltage signal VO, VO ', Vr, Vr ' by phase-locked amplification channel, the output of synchronous demodulation passage enters the A/D ALT-CH alternate channel of single-chip microcomputer simultaneously, carries out computing by single-chip microcomputer according to the data of gathering.
After instrument installs; at first opening a branch of wavelength that the power supply of measuring head sends by semiconductor laser (1) is 670nm; the near field of light spot diameter is the directional light of φ 5; be modulated into the alternation light of 1KHZ through total reflective mirror (27) directive chopper wheel (28); this alternation light is through beam divider (29); a branch of light is divided into two bundles (transmitted light and reflected light); splitting ratio is 4: 1; transmitted light is through total reflective mirror (30) and cut the beam divider (36) that CD (32) directive splitting ratio is 9:1; light intensity with 10% incides on the detector (silicon photocell) (4) through poly-lens (35); protect window (37) to penetrate tested flue gas through transmitting terminal another part light intensity and enter receiving end, incide on the detector (8) through receiving end protection window (38) and condenser (39).From a branch of reflected light of beam divider (29) through cutting CD (32), total reflective mirror (34), (33) directive beam divider (36); reflected light with 10% incides on the detector (4) through condenser (35); and another part transmitted light enters optical fiber coupling head (5) through protection window (37); be transferred to the optical fiber coupling head (6) of receiving end through optical cable (25), protection window (38) and the poly-lens (39) through receiving end incide on the detector (8) again.
The light signal note that incides on the detector (4) is made Io and Io ', the light signal note that incides on the detector (8) is made Ir and Ir ', these four signals become corresponding four voltage signals note to make Vo, Vo ', Vr, Vr ' after the detector conversion, amplify after transmission cable is transferred to the synchronous conciliation passage and the phase-locked amplification channel of secondary instrument through prime amplifier (3), (9) respectively.
After the power supply 58 of secondary instrument is opened, at first set the work date by numerical key 56, time-write interval (how long printing once), it is correct to judge that the date is provided with, after setting is finished, display restPoses, 6 figure place sign indicating number tube displays 51 show 00.0000, program loop wait-for-response external interrupt, 1 second left once interruption by computing machine, moves the external interrupt subroutine, the voltage signal that will carry out after the analog signal processing carries out the A/D conversion, carry out corresponding functional operation by 8098 single-chip microcomputers according to different function selecting, the computing of optical fiber coupling coefficient when functional key 60 selections were static the debugging at 0 o'clock, selecting at 1 o'clock is the turbidity computing, turbidity pilot lamp 52 is bright, selecting at 2 o'clock is the concentration computing, and concentration pilot lamp 53 is bright, and continuous coverage is the result shown by charactron, gauge outfit indication and print record.If turbidity or concentration value carry out sound when surpassing setting, light is reported to the police.Regulation voltage indication switch 59 can be checked each operating voltage of secondary instrument.
Claims (6)
1, the on-line monitoring method of a kind of gas turbidity and dust content, to be divided into from the single light beam of laser instrument in a side of tested gas when it is characterized in that measuring and measuring and with reference to two-beam, and transmitting terminal and receiving end split the both sides at tested gas, this structure is called twin-beam, monochromatic light journey double-end measurement system, beam modulation is become the alternation light of required frequency by chopper wheel, from the transmitted light of first beam divider and reflected light under the effect of cutting CD that a synchronous motor drives behind second beam divider, its two bundles reflected light is periodically alternately incided on the photoelectric commutator that places tested gas one side, as reference light, note is made I0 and I0 ' respectively, two bundle transmitted lights from second beam divider, a branch ofly pass tested gas as measuring light, a branch of through the optical fiber coupled transfer as reference light, what measuring light and reference light replaced incides on the photoelectric commutator that places tested another survey of gas, note is made Ir and Ir ' respectively, make the light intensity that incides on the photoelectric commutator ascending and descending variation occur by same period, after analog signal processing, form the trapezoidal wave of certain amplitude, by the data handling system collection and calculate the transmitance T=Ir/I0=e of tested gas according to Lambert-Beer's law
-acL, and then the turbidity that calculates tested gas is Q=1-T, the concentration of tested gas is C=Ln (1/T)/(α L) (in the formula: the attenuation coefficient of α-tested gas, the concentration of the tested gas of C-, the thickness of the tested gas of L-).
2, the on-line monitoring instrument of a kind of gas turbidity and dust content, it comprises light path and photo-translating system, air cleaning system, the analog signal processing system, data handling system, light path and photo-translating system comprise laser instrument 1, the transmitting terminal 2 of light path, the receiving end 7 of light path, photoelectric commutator 4,8, fiber coupler 5,6, Transmission Fibers 25, air cleaning system comprises air purifying room 10,11, air cleaner 12,13, the analog signal processing system comprises prime amplifier 3,9, power supply 14, terminal box 15, analogy signal processing unit 16, data handling system comprises A/D converter 17, data processing unit 18, nixie display 19, mini-printer 20, analog quantity indicator 21, analog quantity output 22, sound, light warning device 23 is formed, its decontamination chamber 10, the both sides that 11 symmetries are placed on tested gas respectively with air cleaner 12,13 connect, the light beam that laser instrument 1 sends enters the transmitting terminal 2 of light path system, the light signal part that the transmitting terminal 2 of light path system sends is through the decontamination chamber 10, tested gas, the receiving end 7 of decontamination chamber's 11 directive light path systems, a part is through fiber coupler 5, optical fiber 25, the receiving end 7 of fiber coupler 6 transmission directive light path systems, its light signal replaces enters photoelectric commutator 8, the ac signal of photoelectric commutator 8 outputs enters prime amplifier 9, a part is directly through photoelectric commutator 4 outputs, its electric signal enters prime amplifier 3, prime amplifier 3, the signal of 9 outputs connects with analogy signal processing unit 16 through terminal box 15 respectively, and the output terminal of simulating signal enters data processing unit through A/D converter 17 to carry out data processing and demonstration and print measurement result.
3; monitor according to claim 2; it is characterized in that light path transmitting terminal 2 comprises plane total reflective mirror 27; 30; 33; 34; first beam divider 29; second beam divider 36; convergent lens 35; chopper wheel 28; cut CD 32; protection window 37; the light path receiving end comprises protection window 38; convergent lens 39; the light of being launched by laser instrument 1 reflects through total reflective mirror 27; reflected light is through chopper wheel 28; first beam divider 29 is divided into transmitted light and reflected light; wherein transmitted light is through catoptron 30 with cut CD 32 directives second beam divider 36; a part is made Ir for the transmitted light note; a part is made Io for the reflected light note; transmitted light penetrates tested gas through transmitting terminal protection window 37 and enters receiving end; incide on the photoelectric commutator 8 through receiving end protection window 38 and convergent lens 39; reflected light incides on the detector 4 through convergent lens 35; from the reflected light of first beam divider 29 through cutting CD 32; total reflective mirror 34; 33 directives, second beam divider 36; a part is made Ir ' for the transmitted light note; a part is made Io ' for the reflected light note; transmitted light enters fiber coupler 5 through protection window 37 and is transferred to receiving end again through the fiber coupler 6 of receiving end through optical cable 25; protection window 38 and convergent lens 39 incide on the photoelectric commutator 8; reflected light incides on the photoelectric commutator 4 through convergent lens 35; photoelectric commutator 4 connects with prime amplifier 3; photoelectric commutator 8 connects with prime amplifier 9; have an aperture on the CD cutting, with the photoelectrical coupler assembling and positioning.
4, monitor according to claim 2, the analogy signal processing unit that it is characterized in that it is formed phase-locked amplification channel by AC amplifier AC1, phase-sensitive detector (PSD) PSD1, low-pass filter LPF1, direct current amplifier DC1, AC amplifier AC2, phase sensitive amplifier PSD2, low-pass filter LPF2, direct current amplifier DC2 form the synchronous demodulation passage, phase shifter one terminates between AC amplifier AC2 and the phase sensitive amplifier PSD2, and the other end connects with phase sensitive amplifier PSD1.
5, monitor according to claim 2 is characterized in that the head of fiber coupler installs dustproof sleeve 40 additional.
6, monitor according to claim 2 is characterized in that adopting semiconductor laser.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94108036A CN1038614C (en) | 1994-08-05 | 1994-08-05 | In-line monitoring method of gas turbidity and dusty concentration and its monitor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN94108036A CN1038614C (en) | 1994-08-05 | 1994-08-05 | In-line monitoring method of gas turbidity and dusty concentration and its monitor |
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| Publication Number | Publication Date |
|---|---|
| CN1106138A true CN1106138A (en) | 1995-08-02 |
| CN1038614C CN1038614C (en) | 1998-06-03 |
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| CN94108036A Expired - Fee Related CN1038614C (en) | 1994-08-05 | 1994-08-05 | In-line monitoring method of gas turbidity and dusty concentration and its monitor |
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| CN (1) | CN1038614C (en) |
Cited By (8)
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| CN1995973B (en) * | 2006-10-11 | 2010-04-07 | 中国科学院上海微系统与信息技术研究所 | Gas measuring method based on semiconductor laser moding characteristics and sensor therefor |
| CN102608010A (en) * | 2012-03-28 | 2012-07-25 | 姚水良 | Particulate matter (PM) detecting method and equipment |
| CN102854109A (en) * | 2012-07-31 | 2013-01-02 | 安徽皖仪科技股份有限公司 | Novel intelligent sensor for measuring dust concentration by using laser backscattering method |
| CN101981432B (en) * | 2008-10-29 | 2013-07-10 | 三菱重工业株式会社 | Method and apparatus for measuring concentration |
| CN103344614A (en) * | 2013-07-02 | 2013-10-09 | 中国科学院合肥物质科学研究院 | Device and method for measuring atmospheric transmissivity at high precision |
| CN104502313A (en) * | 2014-12-10 | 2015-04-08 | 浙江浙大鸣泉科技有限公司 | Novel optical platform for transmission style smoke limit meter |
| CN105259137A (en) * | 2015-11-04 | 2016-01-20 | 安徽中科智泰光电测控科技有限公司 | Automatic absorption spectrum online in-situ measuring device for laser ammonia escape of pipeline |
| CN105651741A (en) * | 2014-12-01 | 2016-06-08 | 横河电机株式会社 | Laser gas analyzer |
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| CN103439233B (en) * | 2013-08-30 | 2015-10-28 | 苏州奥德克光电有限公司 | Flue dust concentration detection system |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU813205A1 (en) * | 1978-11-10 | 1981-03-15 | Особое Конструкторское Бюро Техни-Ческой Кибернетики Ленинградскогоордена Ленина Политехническогоинститута Имени M.И.Калинина | Gas analyzer |
| US4305663A (en) * | 1979-03-02 | 1981-12-15 | Pye (Electronic Products) Limited | Spectrophotometer |
| CN85101725B (en) * | 1985-04-01 | 1987-10-07 | 中国科学院长春光学精密机械研究所 | Dual light beams optical system for monitoring the thickness of optical coating |
| CN85109253B (en) * | 1985-12-20 | 1988-11-23 | 内蒙古电力试验研究所 | Method and device of measuring powder concentration by dual light beams in opposite direction |
| US5095913A (en) * | 1989-09-01 | 1992-03-17 | Critikon, Inc. | Shutterless optically stabilized capnograph |
| RU1825419C (en) * | 1991-05-24 | 1993-06-30 | Научно-производственное объединение "Государственный институт прикладной оптики" | Gas analyzer |
| CN1070266A (en) * | 1992-08-03 | 1993-03-24 | 上海科学技术实业总公司 | Double-beam compensating turbidimeter |
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1994
- 1994-08-05 CN CN94108036A patent/CN1038614C/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1995973B (en) * | 2006-10-11 | 2010-04-07 | 中国科学院上海微系统与信息技术研究所 | Gas measuring method based on semiconductor laser moding characteristics and sensor therefor |
| CN101981432B (en) * | 2008-10-29 | 2013-07-10 | 三菱重工业株式会社 | Method and apparatus for measuring concentration |
| CN102608010A (en) * | 2012-03-28 | 2012-07-25 | 姚水良 | Particulate matter (PM) detecting method and equipment |
| CN102854109A (en) * | 2012-07-31 | 2013-01-02 | 安徽皖仪科技股份有限公司 | Novel intelligent sensor for measuring dust concentration by using laser backscattering method |
| CN103344614A (en) * | 2013-07-02 | 2013-10-09 | 中国科学院合肥物质科学研究院 | Device and method for measuring atmospheric transmissivity at high precision |
| CN105651741A (en) * | 2014-12-01 | 2016-06-08 | 横河电机株式会社 | Laser gas analyzer |
| CN105651741B (en) * | 2014-12-01 | 2018-10-26 | 横河电机株式会社 | Laser gas analysis device |
| CN104502313A (en) * | 2014-12-10 | 2015-04-08 | 浙江浙大鸣泉科技有限公司 | Novel optical platform for transmission style smoke limit meter |
| CN105259137A (en) * | 2015-11-04 | 2016-01-20 | 安徽中科智泰光电测控科技有限公司 | Automatic absorption spectrum online in-situ measuring device for laser ammonia escape of pipeline |
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|---|---|
| CN1038614C (en) | 1998-06-03 |
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