CN1038614C - In-line monitoring method of gas turbidity and dusty concentration and its monitor - Google Patents

Abstract

The present invention relates to an on-line monitoring method of gas turbidity and dusty concentration and a monitoring device, which is mainly characterized in that (1) the present invention combines advanced technology, such as laser, optical fibers, phase locking, microcomputers, etc., into a whole; (2) a double-end system structure of a single optical path, double optical beams and transmitting-receiving split; optical cables are bridged between the receiving end and the transmitting end; coupling transmission is carried out to reference light; relevant measurement is realized; (3) the front part of the optical fiber coupling head is additionally provided with a semi-closed dust-proof sleeve barrel; the accuracy of the relevant measurement is ensured; (4) an optical disc is additionally arranged in the light path, and accordingly, the measurement light and the reference light successively output; the two light beams realize to commonly use a detector and a signal processing system; (5) semiconductor laser with small volume and long service life is adopted as the light source; (6) phase locking technique is adopted for analogue signal processing; an 8098 single-chip microcomputer is adopted to carry out data processing, and accordingly, the long time operation of the device is stable and reliable under bad working environment; the measuring accuracy is high, and the installation and the maintenance are convenient.

Description

The on-line monitoring method and the monitor thereof of gas turbidity and dust content

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 operate numerous institute, measuring error is big, far the requirement of incompatibility current environment pollution Monitoring.Non-sedimentation monitoring means, development in recent years be than piece, utilizes the non-contact on-line monitor of manufacturing of optical principle widely-used abroad in non-sedimentation.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 error 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 the DURAG company of Germany produces though added fan blower in measuring system, carries out air blast to the window face and isolates, and the casual dust stratification of not stopping the window face pollutes, and still has the measuring error that causes thus in the use.As M400 type produced in USA and DYNATRON1100 type turbidimeter,,, also can not realize effectively measuring error is compensated automatically because the pollution of detector photosurface does not take measures to overcome though increased window surface state detector.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 flue gas end stream 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.

The on-line monitoring method of this gas turbidity and dust content is the both sides that transmitting terminal and receiving end place tested gas respectively, to become the alternation light of required frequency from the single beam modulation of laser instrument at transmitting terminal, this alternation light is divided into two-beam by first beam divider, this two-beam alternately incides second beam divider under the effect of cutting CD, be divided into four bundle light i.e. two bundle reflected light and two bundle transmitted lights, wherein two bundle reflected light are assembled through convergent lens, alternately incide on the same photoelectric commutator of transmitting terminal, remember respectively as reference light and to make I0 and I0 ', two bundles a branch of in the transmitted lights passes tested gas as measuring light, another bundle transmits conduct with reference to light through fiber coupler, measuring light and reference light alternately incide on the same photoelectric commutator of receiving end respectively note through the convergent lens of receiving end makes Ir and Ir ', make the light intensity that is transmitted on the photoelectric commutator ascending and descending variation occur by same period, after analog signal processing, form the square wave of certain width, by data handling system according to lambert---Beer law calculates transmitance T=(Ir/I0) (I0 '/Ir ') K=e of tested gas ^{-α cL}And then the turbidity that calculates tested gas is Q=1-T, the dust content of tested gas is C=Ln (1/T)/α L (in the formula: α---the attenuation coefficient of tested gas, the light path that L---measuring light is passed through in tested gas, the coupling coefficient of K---Transmission Fibers).

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, wiring closes 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 alternately 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 analogue signal processor 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 photoelectric commutator 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 reflected light Io '; 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 as system source.

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, twin-beam measuring 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 5 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 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 ^{-β 1 ' L1 '}E ^{-β 2 ' L2 '}E ^{-β 3 ' L3 '}(2) two sections decay that light path caused are from dust stratification on window and the window and lens 35,39 to two-beam through L1, L3.And window is a uniform thickness, dust stratification on the window is to be caused by casual pollution of the flying dust of random brush, dust stratification distributes can regard uniform as, two-beam is transferred to the uniform thickness position at the incidence point of lens, on these two sections light paths except that window is exposed to, remainder all 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 that a constant is represented with K, be called the coupling coefficient of Transmission Fibers, that is:

The turbidity of flue gas is the Q=1-T cigarette $=1-\frac{\mathrm{Ir}3\·I{O}^{\′}}{\mathrm{Ir}{3}^{\′}\·\mathrm{IO}}\·K----\left(4\right)$ β 2=α C in the formula (3), the flue gas of α-unit concentration on unit length to the attenuation coefficient of light

The mass concentration of C-flue gas is promptly: $e^{-\mathrm{\&alpha;}\&CenterDot;C\&CenterDot;\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="C9410803600151.png,C9410803600221.png"\; state="\{\{state\}\}">L</figure-callout>}2}=\frac{\mathrm{Ir}3\&CenterDot;I{O}^{\&prime;}}{\mathrm{IO}\&CenterDot;\mathrm{Ir}{3}^{\&prime;}}\&CenterDot;K$ These formula both sides mass concentration expression formula that conversion draws flue gas of taking the logarithm is: (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 optical fiber coupling head 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 optical fiber coupling head 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 that full reception improves monitoring accuracy, and is lower to the output power and the divergence requirement of light source simultaneously, is convenient to install, adjusts, keeps in repair.

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 flue gas end stream 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 and sweep the district, 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 go the rounds measurement according to requiring to make portable with protecting.Therefore, this instrument is pollution source on-line monitoring or the touring desirable instrument that detects, and also is to connect the formation closed-loop control system with CPU (central processing unit), 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 twin-beam measuring system synoptic diagram

Fig. 6 is the analogy signal processing unit structured flowchart

Fig. 7 is the analogy signal processing unit 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 processor structured flowchart

Among the figure:

1--light device 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--wiring is closed

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

--phase shifter

--the ac voltage measurement signal

--the 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-/IO interface (1)

74--power amplifier 75--storer

76--I/O interface (2) 77--photoisolator

Frame of broken lines I is the transmitting terminal of monitor among Fig. 1; frame of broken lines II is the receiving end of monitor; 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-filtering gas, 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 twin-beam measuring 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 ACI, 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.AC amplifier AC, phase sensitive amplifier 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, Vo, Vr ', Vo ' 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 Peset, 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 dipped beam spot diameter is the directional light of 5; be modulated into the alternation light of 1KHZ through total reflective mirror 27 directive chopper wheels 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 to cut CD 32 directive splitting ratios be 9: 1 beam divider 36; light intensity with 10% incides on the detector (silicon photocell) 4 through convergent lens 35; another part light intensity is penetrated tested flue gas through transmitting terminal protection window 37 enter receiving end, incide on the detector 8 through receiving end protection window 38 and convergent lens 39.From a branch of reflected light of beam divider 29 through cutting CD 32, total reflective mirror 34,33 directive beam dividers 36; reflected light with 10% incides on the detector 4 through convergent lens 35; and another part transmitted light enters 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 convergent lens 39 through receiving end incides 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 demodulation 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 value 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 gas turbidity and dust content, it is characterized in that transmitting terminal and receiving end place the both sides of tested gas respectively, to become the alternation light of required frequency from the single beam modulation of laser instrument at transmitting terminal, this alternation light is divided into two-beam by first beam divider, this two-beam alternately incides second beam divider under the effect of cutting CD, be divided into four bundle light i.e. two bundle reflected light and two bundle transmitted lights, wherein two bundle reflected light are assembled through convergent lens, alternately incide on the same photoelectric commutator of transmitting terminal, remember respectively as reference light and to make I0 and I0 ', two bundles a branch of in the transmitted lights passes tested gas as measuring light, another bundle transmits conduct with reference to light through fiber coupler, measuring light and reference light alternately incide on the same photoelectric commutator of receiving end respectively note through the convergent lens of receiving end makes Ir and Ir ', make the light intensity that is transmitted on the photoelectric commutator ascending and descending variation occur by same period, after analog signal processing, form the square wave of certain width, by data handling system according to lambert---Beer law calculates transmitance T=(Ir/I0) (I0 '/Ir ') K=e of tested gas ^{-α cL}And then the turbidity that calculates tested gas is Q=1-T, the dust content of tested gas is C=Ln (1/T)/α .L (in the formula: α---the attenuation coefficient of tested gas, the light path that L---measuring light is passed through in tested gas, the coupling coefficient of K---Transmission Fibers).

2. the on-line monitoring instrument 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, the light path and the photo-translating system that it is characterized in that it comprise laser instrument (1), the transmitting terminal of light path (2), the receiving end of light path (7), 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), (15) are closed in wiring, 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 (10,11) symmetry be placed on tested gas both sides 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 of light path system (2) sends is through the decontamination chamber (10), tested gas, the receiving end (7) of decontamination chamber (11) directive light path system, a part is through fiber coupler (5), optical fiber (25), the receiving end (7) with the light path system is penetrated in fiber coupler (6) transmission, its light signal alternately enters photoelectric commutator (8), the ac signal of photoelectric commutator (8) output enters prime amplifier (9), a part is directly exported through photoelectric commutator (4), its electric signal enters prime amplifier (3), prime amplifier (3,9) Shu Chu signal 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 (2 7); 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) directive 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 is protected window (37) to penetrate tested gas through transmitting terminal and is entered receiving end; incide on the photoelectric commutator (8) through receiving end protection window (38) and convergence light microscopic (39); reflected light incides on the photoelectric commutator (4) through convergent lens (35); from the reflected light of first beam divider (29) through cutting CD (32); total reflective mirror (34; 33) directive 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 the receiving end fiber coupler (6) through receiving again through optical cable (25); protection window (38) and convergence light microscopic (39) incide on the photoelectric commutator (8); reflected light incides on the photoelectric commutator (4) through assembling light microscopic (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, AC amplifier AC2, phase sensitive amplifier PSD2, low-pass filter LPF2, direct current amplifier DC2 by AC amplifier AC1, phase-sensitive detector (PSD) PSD1, low-pass filter LPF1, direct current amplifier DC1 and is formed 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, it 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 as system source.

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