CN209117068U - A kind of particulate matter on-Line Monitor Device - Google Patents
A kind of particulate matter on-Line Monitor Device Download PDFInfo
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- CN209117068U CN209117068U CN201822133531.4U CN201822133531U CN209117068U CN 209117068 U CN209117068 U CN 209117068U CN 201822133531 U CN201822133531 U CN 201822133531U CN 209117068 U CN209117068 U CN 209117068U
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Abstract
The utility model relates to one kind to be used for particulate matter on-Line Monitor Device, including light source, photodetector array, signal conditioning circuit and computer including multiple photodetectors are incident in the flue gas containing dust or discharge gas using coherent laser as light source；The associated laser device is narrow linewidth laser；The forward scattering light that photodetector array reception by being placed in light source opposite side obtains after being scattered by dust；Each photodetector of photodetector array is before equipped with collecting lens respectively, and is distributed on different scattering directions；Forward scattering light generates interference on the photodetector array faces in difference scattering directions, is formed at any time and the coherent light signal of spatial variations after dust particle scatters；Photoelectric detector detects the coherent light signal changed over time, and computer is admitted to after signal conditioning circuit.The utility model can realize that low concentration particulate matter is continuously monitored on-line.
Description
Technical field
The utility model belongs to environment supervision instrument and online monitoring instruments field, relates generally to a kind of low concentration particulate matter
On-Line Monitor Device.
Background technique
Fine particle is China's urban air pollution main component in atmosphere, and especially particle size range is between 2.5-10um
Fine particle residence time in an atmosphere is long, propagation distance is remote, it is larger for people's health and national economy harm.Beijing-Tianjin
The lasting continuous haze weather of large area in area has also caused each side for the pass of fine particle monitoring and administering method
Note.The particulate matter of industrial pollution source emission is one of main source of Brownish haze, dust monitoring and improvement in industrial production
It is of increasing concern.
Particulate matter on-line monitoring is the foundation for controlling industrial pollution source emission and being administered, dense to the dust of Work places
Degree timely and effectively detects, and can better grasp dust concentration situation, provide important foundation for effectively dedusting and depositing dust.Mesh
Preceding common dust measurement method is mainly by capacitance method, piezo-electric crystal actinobolia, β ray method, oscillating balance method etc., these methods
It generally requires to carry out sampling pretreatment, including filtering and blow device, is difficult to realize on-line continuous measurement.
Light scattering method is that particle concentration and particle diameter distribution measurement can be achieved at the same time in one kind, and has in real time, is connected online
Continuous advantage.Its principle is that scattering of the fine particle to light in medium is utilized, and the light that light source issues is readily scattered by particulates, and directive is each
A direction, the size and particle size and optical wavelength of scattered light intensity are closely related, carry out photometric measurement at this time, so that it may obtain
Grain object measurement of concetration.Using optical principle, fast response time is convenient and efficient, it can be achieved that live portable monitoring, continuous online prison
It surveys, meets the needs of particulate matter inorganization control, to improve the efficiency and validity of environmental management.
At present in particle concentration on-line monitoring, frequently with the laser signal that back scattering principle, light source issue, irradiation
To after the gas containing particulate matter, rear orientation light is generated, according to scattering theory it is found that the intensity and flue dust of backscatter signal
Concentration is at positive variation.It is strong by backscatter signal using this principle instrument but since particulate matter back scattering is relatively weak
Degree limitation, sensitivity is low, and the discharge of some low concentration flue dust can not be detected, secondly, factors such as particulate matter flow velocity are uneven
Also measurement can be had some impact on.In addition, the backscatter intensity calculating that most methods can only often measure at present
Grain object concentration, can not accurately obtain particle size, the on-line checking of the parameters such as flow velocity, therefore cannot achieve granular material discharged
Comprehensive monitoring.
Utility model content
The utility model is needed for particle concentration on-line monitoring in industrial production and other occasions, especially low concentration
It is needed with discontinuous dust on-line monitoring is discharged, a kind of base particulate matter on-Line Monitor Device is provided.Technical solution is as follows:
One kind is used for particulate matter on-Line Monitor Device, including light source, photodetector array including multiple photodetectors,
Signal conditioning circuit and computer, which is characterized in that using coherent laser as light source, be incident on the flue gas containing dust or
In person's discharge gas；The associated laser device is narrow linewidth laser, is realized using laser diode current driving and temperature control circuit
Laser output power meter is Wavelength stabilized, laser emitting light through expanding and face incidence shaping after, uniformly divide on the plane of incidence
Cloth realizes biggish area of detection；
The forward scattering light that photodetector array reception by being placed in light source opposite side obtains after being scattered by dust；Photoelectricity
Each photodetector of detection array is before equipped with collecting lens respectively, and is distributed on different scattering directions；Forward scattering
Light generates interference on the photodetector array face in difference scattering direction, is formed at any time and empty after dust particle scatters
Between the coherent light signal that changes；Photoelectric detector detects the coherent light signal changed over time, is converted into voltage signal, passes through
Computer is admitted to after signal conditioning circuit.
Because the utility model adopts the above technical scheme, it has the following advantages:
1, the utility model disturbs coherent signal caused by particulate matter scattering using the relevant testing principle of forward scattering
Sensitivity with higher, and the influence of the factors for light intensity such as air-flow variation in environment can be reduced.In addition, forward scattering
Detection mode can reduce influence of the tube wall reflection for scattered light signal,
2, the laser used in the utility model has preferable coherence, utilizes laser for narrow linewidth laser
It is Wavelength stabilized that laser output power meter may be implemented in the driving of device electric current and temperature control circuit.Laser emitting light process expands and face
It after incident shaping, is uniformly distributed on the plane of incidence, to realize biggish area of detection, guarantees signal stabilization, not by particle
Logistics speed disturbing influence.
3, forward scattering coherent optical detection device is set to laser light incident opposite side, wherein filtering containing signal and improving single filter
Except other frequency noise ingredients in signal, signal-to-noise ratio is improved, A/D acquisition device converts analog signals into digital signal, and send
Enter computer to be further processed.
Detailed description of the invention
Fig. 1 is the particle analyte detection measuring system schematic diagram being concerned in the utility model embodiment based on forward scattering
Fig. 2 is signal for measure Forward scattering signal angular distribution calculating particle size in the utility model embodiment
Figure
Fig. 3 is that detection unit is arranged on different location in gas flow direction containing particulate matter in the utility model embodiment
Measure the schematic diagram of particulate matter flow velocity
Fig. 4 is power Spectral Estimation and particle concentration calculation flow chart
Fig. 5 is the flow chart that particle size calculating is carried out according to forward scattering angular distribution
Different location detects that relevant time varying signal calculates particle logistics in gas flow direction containing particulate matter according to Fig. 6
The algorithm flow chart of speed
Specific embodiment
The utility model main contents include:
The utility model provides a kind of particulate matter on-Line Monitor Device based on laser Forward scattering signal, including light
Source, photodetector array, signal conditioning circuit and computer including multiple photodetectors, which is characterized in that using relevant
Laser is incident in the flue gas containing dust or discharge gas as light source；The associated laser device swashs for narrow linewidth
Light device realizes that laser output power meter is Wavelength stabilized using laser diode current driving and temperature control circuit, laser emitting light warp
Cross expand and face incidence shaping after, be uniformly distributed on the plane of incidence, realize biggish area of detection；
The forward scattering light that photodetector array reception by being placed in light source opposite side obtains after being scattered by dust；Photoelectricity
Each photodetector of detection array is before equipped with collecting lens respectively, and is distributed on different scattering directions；Forward scattering
Light generates interference on the photodetector array face in difference scattering direction, is formed at any time and empty after dust particle scatters
Between the coherent light signal that changes；Photoelectric detector detects the coherent light signal changed over time, is converted into voltage signal, and pass through
Computer is admitted to after crossing signal conditioning circuit.
Measurement process includes: with method
1. the measurement of forward scattering angular distribution and particle size calculation method.Each photoelectricity of photodetector array is visited
It surveys device and is before equipped with collecting lens respectively, and be distributed on different scattering directions, can measure to obtain different angle light intensity
Distribution is expressed as function I (α).In order to according to I (α) calculate particle size distribution C (r), calculation process as shown in figure 5,
The corresponding I of C (r) (α) is calculated by the method for analog simulation first, using Mie scattering theory and the side Carlo Monte
The algorithm that method combines calculates different particle size distribution C (r) corresponding scattering coefficient first with Mie scattering model and items is different
Sex factor further obtains different angle forward scattering light distribution using Monte Carlo simulation method and is expressed as I ' (α),
The corresponding distribution array of different particle size distribution can indicate are as follows: [I1’(α),I2’(α),…In-1’(α),In' (α)], then it will survey
Amount result I (α) is compared with the numerical value in matrix, using look-up interpolations, closest value is selected, to obtain corresponding grain
Diameter is distributed C (r).
2. measuring concentration of granules in certain and algorithm, be arranged according to fig. 2 the detection unit measurement of forward scattering different angle with
The forward scattering coherent signal I (t) of time change.In order to calculate particle concentration according to I (t), different are calculated first
The corresponding forward scattering light path distribution of grain object concentration C, is expressed as L (c), then according to L (c) be calculated coherent signal frequency and
Amplitude distribution, calculation formula are as follows:
Then it is sent out using auto-correlation function power Spectral Estimation, seeks I ' (t) corresponding power spectrum, P ' (w) is expressed as, in difference
Under particle concentration C assumes, the frequency and amplitude of power spectrum function P ' (w) of obtained simulation coherent signal are different, can be with table
It is shown as matrix form: [P1’(w),P2’(w),…Pn-1’(w),Pn’(w)] power that, then measurement result I (t) is calculated
Spectral function P (w) is compared with the numerical value in matrix, using look-up interpolations, closest value is selected, to obtain corresponding
Grain object concentration.
3. being arranged containing the measurement of particulate matter air-flow velocity and calculation method containing particulate matter flow of air direction different location
Detection unit detects that scattering particles passes sequentially through the coherent signal changed over time caused by two positions, respectively indicates
For I1(t) and I2(t).Cross-correlation function calculating is carried out to two time-varying coherent signals, is prolonged relatively between available two signals
The slow time, that is, containing particulate matter air-flow by the time of two positions, the relative position being then arranged according to detector can
Particle flow rate is calculated.
Claims (1)
1. a kind of particulate matter on-Line Monitor Device, including light source, photodetector array, signal tune including multiple photodetectors
Manage circuit and computer, which is characterized in that using coherent laser as light source, be incident on the flue gas containing dust or discharge
In gas；The coherent laser is narrow linewidth laser, realizes laser using laser diode current driving and temperature control circuit
Output power meter is Wavelength stabilized, laser emitting light through expanding and face incidence shaping after, be uniformly distributed on the plane of incidence, realize
Biggish area of detection；
The forward scattering light that photodetector array reception by being placed in light source opposite side obtains after being scattered by dust；Photoelectric Detection
Each photodetector of array is before equipped with collecting lens respectively, and is distributed on different scattering directions；Forward scattering light warp
After crossing dust particle scattering, interference is generated on the photodetector array face in difference scattering direction, is formed at any time and space becomes
The coherent light signal of change；Photoelectric detector detects the coherent light signal changed over time, is converted into voltage signal, by signal
Computer is admitted to after conditioning circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201822133531.4U CN209117068U (en) | 2018-12-18 | 2018-12-18 | A kind of particulate matter on-Line Monitor Device |
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| CN201822133531.4U CN209117068U (en) | 2018-12-18 | 2018-12-18 | A kind of particulate matter on-Line Monitor Device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109443445A (en) * | 2018-12-18 | 2019-03-08 | 苏州同阳科技发展有限公司 | A kind of particulate matter on-Line Monitor Device and method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109443445A (en) * | 2018-12-18 | 2019-03-08 | 苏州同阳科技发展有限公司 | A kind of particulate matter on-Line Monitor Device and method |
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