Gas concentration measurement system in ultraviolet gas analyzer
Technical field
Gas concentration measurement system in ultraviolet gas analyzer of the present invention, belongs to the technical field of flue gas inspection.
Background technique
Currently, existing gas analyzer mainly utilizes ultraviolet fluorescence method and tunable laser method on the market, it is ultraviolet glimmering
Light method can be used to measure sulfur dioxide, when principle is that the ultraviolet lighting near 190 ~ 230 nm is mapped to tested gas, two
The energy of sulfur oxide molecule absorption ultraviolet light, molecule, which is excited, issues fluorescence when returning to ground state from high level;N2 in atmosphere,
O2 does not cause " fluorescent quenching effect " substantially, and the SO2 of excitation state mainly returns to ground state by fluorescence process, utilizes photomultiplier tube
The fluorescence of hair is received, Ultraluminescence hair is very high to the monitoring sensitivity of SO2, and fluorescent intensity size can reflect sulfur dioxide
Concentration;This method can monitor the low concentration SO 2 of the ppb order of magnitude, while dynamic range and the linearity are fine, therefore multi-purpose
It monitors, but is applied in flue gas monitoring in quality of air environment, need to be equipped with dilution method sampler, system is very multiple
It is miscellaneous.
Tunable laser(Tunable Laser), laser output wavelength can continuously be changed in a certain range by referring to
Laser, this laser it is widely used, can be used for spectroscopy, photochemistry, medicine, biology, integrated optics, pollution prison
Survey, semiconductor material processing, information processing and communication etc.;Due to laser wavelength wide coverage, intensity is big, and spectral line is narrow, can be with
For the detection of multiple gases, general there are two types of working methods:One is the back scattering using tested gas, obtain contamination gas
The distribution of body spatially, is based on differential absorption lidar technology, and another kind is to obtain being averaged on light path direction using reflector
Concentration, transmitted light and transmitting light meet langbobier law, and the advantage of this method is can almost to measure all gas, and response is fast
Precision is high.The disadvantage is that the cost of the tunable laser of middle infrared is too high, gas with various detection need to be equipped with different light sources, and close
The absorption line strengths that the laser of infrared region generates are lower, are unfavorable for measuring.
Summary of the invention
The present invention overcomes the shortcomings of the prior art, and technical problem to be solved is:There is provided a kind of measurement accuracy compared with
Gas concentration measurement system in high ultraviolet gas analyzer.
In order to solve the above-mentioned technical problem, the technical solution adopted by the present invention is:Gas concentration in ultraviolet gas analyzer
Measuring system, including:For storing the sealed gas chamber of gas and for the light source of the emitting parallel light into gas chamber, the closed gas
One end of room is provided with the fibre optical sensor for receiving directional light, and the fibre optical sensor is connected with spectrometer, described closed
Be provided with temperature sensor, oxygen sensor, escape pipe and air inlet pipe on gas chamber, the temperature sensor, oxygen sensor and
Spectrometer is connected with the control circuit board, and the control circuit board also passes through light source driving circuit plate and is connected with light source;Institute
Stating control circuit board includes:Main controller, and the temperature signal regulation and Acquisition Circuit, oxygen signal that are connected respectively with main controller
Conditioning is shown with Acquisition Circuit, control circuit for light source, pipeline control circuit, recognition by pressing keys circuit, communication interface circuit, display screen
Control circuit, spectroscopic acquisition control circuit;The temperature sensor, oxygen sensor, light source driving circuit plate, spectrometer
It is improved and Acquisition Circuit, control circuit for light source, spectral signal with the temperature signal regulation and Acquisition Circuit, oxygen signal respectively
Acquisition control circuit is connected.
Preferably, solenoid valve, the solenoid valve and air intake duct and sample gas air inlet pipe phase are provided in the air inlet pipe
Even, it is provided with sampling pump on the air intake duct, the solenoid valve and sampling pump are connected with the pipeline control circuit.
The system also includes HMI human-computer interaction interface, the HMI human-computer interaction interface is provided with display screen and key,
The display screen is connected with display screen display control circuit, and the key is connected with recognition by pressing keys circuit.
The control circuit board further includes current output circuit and switching signal output circuit, and the control circuit board is also wrapped
Power-switching circuit is included, the power-switching circuit is connected with the main controller, the model of the main controller
The microcontroller of STM32F103ZET6, the communication interface circuit include:RS232 interface circuit and RS485 interface circuit.
The present invention has the advantages that compared with prior art:
1, in the present invention, the environmental data of sealed gas chamber can be acquired in real time by temperature sensor, oxygen sensor, passed through
Spectrometer can acquire the spectral signal that gas is tested in sealed gas chamber, and the temperature sensor, oxygen sensor and spectrometer are equal
It is connected with control circuit board, the control circuit board handles the environmental data of the spectral signal of spectrometer collection, sealed gas chamber, and
The spectral signal received is converted into gas concentration signal;The present invention can eliminate influence of the environmental factor to measuring system, survey
Accuracy of measurement is high, system stability is good.
2, of the invention, by the communication unit of control circuit board, it can be connected with HMI human-computer interaction interface, facilitate work people
Observation and operation of the member to measurement data, it is practical.
Detailed description of the invention
The present invention will be further described in detail with reference to the accompanying drawing.
Fig. 1 is the structural diagram of the present invention;
Fig. 2 is electrical block diagram of the invention;
Fig. 3 is the circuit diagram of oxygen signal conditioning and Acquisition Circuit in the present embodiment;
Fig. 4 is the circuit diagram of temperature signal regulation and Acquisition Circuit in the present embodiment;
In figure:1 is sealed gas chamber, and 2 be light source, and 3 be fibre optical sensor, and 4 be spectrometer, and 5 be temperature sensor, and 6 be oxygen
Gas sensor, 7 be escape pipe, and 8 be air inlet pipe, and 9 be control circuit board, and 10 be main controller, and 11 be temperature signal regulation and acquisition
Circuit, 12 be oxygen signal conditioning and Acquisition Circuit, and 13 be control circuit for light source, and 14 be pipeline control circuit, and 15 know for key
Other circuit, 16 be communication interface circuit, and 17 be display screen display control circuit, and 18 be spectroscopic acquisition control circuit, and 19 are
Light source driving circuit plate, 20 be solenoid valve, and 21 be sampling pump, and 22 be current output circuit, and 23 be switching signal output circuit, 24
It is HMI human-computer interaction interface for power-switching circuit, 25,26 be display screen, and 27 be key.
Specific embodiment
As shown in Figures 1 to 4, gas concentration measurement system in ultraviolet gas analyzer, including:For storing the close of gas
It holds one's breath room 1 and the light source 2 for the emitting parallel light into gas chamber, one end of the sealed gas chamber 1 is provided with parallel for receiving
The fibre optical sensor 3 of light, the fibre optical sensor 3 are connected with spectrometer 4, are provided with temperature sensor on the sealed gas chamber 1
5, oxygen sensor 6, escape pipe 7 and air inlet pipe 8, the temperature sensor 5, oxygen sensor 6 and spectrometer 4 with the control
Circuit board 9 processed is connected, and the control circuit board 9 is also connected by light source driving circuit plate 19 with light source 2;The control circuit board
9 include:Main controller 10, and the temperature signal regulation and Acquisition Circuit 11, the oxygen signal that are connected respectively with main controller 10 improve
With Acquisition Circuit 12, control circuit for light source 13, pipeline control circuit 14, recognition by pressing keys circuit 15, communication interface circuit 16, display
Shield display control circuit 17, spectroscopic acquisition control circuit 18;The temperature sensor 5, oxygen sensor 6, light source driving
Circuit board 19 improves and Acquisition Circuit 12, light source control with the temperature signal regulation and Acquisition Circuit 11, oxygen signal respectively
Circuit 13 is connected.
In the present invention, be provided with solenoid valve 20 in the air inlet pipe 8, the solenoid valve 20 and air intake duct and sample gas into
Tracheae is connected, and is provided with sampling pump 21 on the air intake duct, the solenoid valve 20 and sampling pump 21 with the pipeline control
Circuit 14 processed is connected;The system also includes HMI human-computer interaction interface 25, the HMI human-computer interaction interface 25 is provided with display
Screen 26 and key 27, the display screen 26 are connected with display screen display control circuit 17, the key 27 and recognition by pressing keys circuit
15 are connected;The control circuit board 9 further includes current output circuit 22 and switching signal output circuit 23;The main controller 10
The microcontroller of model STM32F103ZET6.
Specifically, the light source 2, light source driving circuit plate 19, spectrometer 4 and fibre optical sensor 3 constitute spectral measurement
Part, the escape pipe 7, air inlet pipe 8, air intake duct, sample gas air inlet pipe, solenoid valve 20 and sampling pump 21 constitute gas and adopt
Sample part, the air sampling part are responsible for by sample gas and air input gas sealed gas chamber 1, for the measurement point of spectral measurement part
Analysis;Further, when solenoid valve 20 is controlled into air, air is pumped into gas chamber by sampling pump 21, is led under the irradiation of light source 2
It crosses the analysis of spectrometer 4 and obtains zero point absorption spectrum, the then control of solenoid valve 20 enters sample gas, at this point, spectrometer 4 will obtain sample
Data are passed to the operation that main control unit carries out gas concentration by communication interface circuit 16 by the absorption spectrum of gas;Meanwhile temperature
The environmental data of the sealed gas chamber 1 of acquisition is sent to main control unit and carries out data processing by sensor 5 and oxygen sensor 6, main
Environmental data and gas concentration data are transferred to HMI human-computer interaction interface 25 by communication interface circuit 16 and carried out by control unit
Data are shown.
In the present embodiment, the resistance value that the temperature signal regulation exports temperature sensor 5 with Acquisition Circuit 11 is passed through
R/V transformation is converted to voltage signal, then signal is transmitted the signal by the ADC interface of main controller 10 by conditioning amplification
It is handled to main controller 10;The oxygen signal conditioning is believed with the weak voltage that Acquisition Circuit 12 exports oxygen sensor 6
Number by conditioning amplification, main controller 10 is then transmitted the signal to by the ADC interface of main controller 10 and is handled;The light
The closing and unlatching that source control circuit 13 passes through the I/O Interface Controller light source of main controller 10;The pipeline control circuit 14 passes through
The open and close of sampling pump 21 and solenoid valve 20 are realized in the control of 10 switch amount of main controller;The recognition by pressing keys circuit 15 is used
In the identification to key-press status;The communication interface circuit 16 includes RS232 interface and RS485 interface, realization and external equipment
Digital communication;The display screen display control circuit 17 for realizing display screen 26 by RS232 interface and main controller 10 into
Row communication, main controller 10 control the update that display screen shows content by the control circuit;The spectroscopic acquisition control electricity
The data exchange between spectrometer and main controller 10 is realized on road 18 by RS232 interface, and the data of exchange include the control of spectrometer
Information processed, the spectral information etc. of spectrometer;The current output circuit 22 realize the inside DA of main controller 10 by sample information with
The form of analog quantity exports, specific work process:The information such as gas concentration, temperature that 10 sampling processing of main controller is crossed are passed through into electricity
The output of swaging formula exports the current signal that these voltages are converted into 4 ~ 20mA;The switching signal output circuit 23 is used for
It realizes the control output 24V switching value of main controller 10, it is allowed to have external control function;In the present invention, the control circuit board 9
Including further including:Power-switching circuit 24, the power-switching circuit 24 are converted to the 24V voltage signal that Switching Power Supply exports
The various power supply signals used inside control circuit board 9, including 12V, 5V, 3.3V etc..
Specifically, the main controller 10 is to the process for the spectroscopic data progress gas concentration operation that spectrometer 4 transmits:
(1)Input information:4 output spectrum digital quantity signal of spectrometer is to main controller 10;
(2)The selection and filtering of wavelength ranges;
(3)Calculate the absorption cross-section of corresponding wave band;
(4)It is calculated by least square method and becomes part in absorption cross-section slowly;
(5)Removal is slow to become part, and remaining fast become partially absorbs section;
(6)Residual absorption section is tested the concentration of gas using area-method inverting;
(7)Interfering with each other between removal gas with various;
(8)Concentration calibration;
(9)The concentration measurement that inverse obtains is exported and is shown on the screen;
(10)Output gas concentration value information.
In the present embodiment, the circuit structure of the oxygen signal conditioning and Acquisition Circuit 12 is:Including current amplifier
It is connected behind one end of the signal negative terminal-IN and connecting resistance R11 of U11, the current amplifier U11 with one end of resistance R13, it is described
The other end of resistance R11 is grounded, the other end of the resistance R13 and connect after the signal output end OUT of current amplifier U11 with electricity
The one end for hindering R14 is connected, and the other end of the resistance R14 simultaneously connects cathode, oxygen after the cathode of diode D11 with diode D12
Gas signal condition is connected with the output terminals A DC_OXY of Acquisition Circuit 12, anode and the power-switching circuit 24 of the diode D11
3.3V power output end be connected, the plus earth of the diode D12, the signal anode+IN of the current amplifier U11 is logical
It crosses resistance R12 to be connected with the signal of oxygen sensor 6 output list V_OXY, the power supply negative terminal V- of the current amplifier U11 connects
Ground, it is defeated with the 12V power supply of power-switching circuit 24 behind one end of the power positive end shunt-wound capacitance C11 of the current amplifier U11
Outlet is connected, the other end ground connection of the capacitor C11.
The temperature signal regulation and the circuit structure of Acquisition Circuit 11 are:Including current amplifier U22, the electric current is put
It is connected behind one end of the signal negative terminal-IN and connecting resistance R28 of big device U22 with one end of resistance R26, the resistance R26's is another
It holds and is connected behind one end of connecting resistance R24 with the signal output end PT of temperature sensor 5, the other end of the resistance R24 simultaneously connects
It is connected behind one end of resistance R25 with one end of the cathode of controllable source of stable pressure U21, one end of resistance R22, resistance R21, the resistance
The other end of R21 is connected with the 12V power output end of the power-switching circuit 24, and the other end of the resistance R22 simultaneously connects electricity
It is connected after hindering one end of R23 with the reference end of controllable source of stable pressure U21, the other end of the resistance R23 simultaneously meets controllable source of stable pressure U21
Anode after be grounded, be connected behind one end of the other end of the resistance R25 and connecting resistance R27 with one end of resistance R210, it is described
It is connected behind the other end of resistance R27 and one end of connecting resistance R29 with the signal anode+IN of current amplifier U22, the resistance
The other end of R210, the other end of resistance R29, current amplifier U22 power supply negative terminal be grounded;The resistance R28's is another
It holds and is connected behind one end of connecting resistance R211 with the signal output end OUT of the current amplifier U22, the resistance R211's is another
One end simultaneously meets the output end V_ after the cathode of diode D21 with the cathode of diode D22, temperature signal regulation and Acquisition Circuit 11
TEMP is connected, and the anode of the diode D22 is connected with the 3.3V power output end of power-switching circuit 24, the diode
The plus earth of D21, behind one end of the power positive end V+ shunt-wound capacitance C21 of the current amplifier U22 with power-switching circuit
24 12V power output end is connected, the other end ground connection of the capacitor C21.
In the present embodiment, sampling pump 21 can choose that small size, ultra-low noise, wide temperature range, the service life is long, stability is good
Gas samping pump, guarantee falls below sampling pump 21 to gas concentration inverting bring error ultimate attainment, and same solenoid valve 20 is also adopted
With quality product, electromagnetic interference is effectively reduced;Meanwhile 2 part of light source passes through emitting ultraviolet light to sealed gas chamber 1, for gas
The absorption spectrometry of body provides prerequisite, and the performance of light source 2 directly determines analysis precision, stability and service life, this
The deuterium lamp light source of a high stability, long-life has been selected in invention, and operation wavelength can cover multiple gases absorption spectra, and spectrum is flat
Slow, optical noise is small, and the energy of ultraviolet portion is higher, meets very much the absorption characteristic in ultraviolet band of analysis multiple gases, together
When substantially increase measurement accuracy and stability of the invention.
To sum up, the present invention has substantive distinguishing features outstanding and significant progress, above in conjunction with attached drawing to reality of the invention
It applies example to be explained in detail, but the present invention is not limited to above-described embodiments, know what those of ordinary skill in the art had
Know in range, it can be with various changes can be made without departing from the purpose of the present invention.