CN100504357C - Method and apparatus for measuring gas concentration based on machinery modulation - Google Patents
Method and apparatus for measuring gas concentration based on machinery modulation Download PDFInfo
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- CN100504357C CN100504357C CN 200410028048 CN200410028048A CN100504357C CN 100504357 C CN100504357 C CN 100504357C CN 200410028048 CN200410028048 CN 200410028048 CN 200410028048 A CN200410028048 A CN 200410028048A CN 100504357 C CN100504357 C CN 100504357C
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Abstract
A method for measuring gas concentration based on mechanical modulation includes utilizing stead state light source to form carrier wave signal through chopper with holes, modulating the formed carrier wave signal by specific gas concentration signal in gas chamber, converting it to be modulated voltage or current signal through filter and light detector and sending the signal to processing controller through signal amplifying circuit for calculating out concentration of gas to be measured. The device for realizing the method is also disclosed.
Description
Technical field the present invention relates to the gas concentration detection range, relates in particular to the by-pass flow formula gas concentration measuring method and the device of mechanical modulation mode.
The present gas concentration monitoring instrument of background technology, comprise and be used in field of medical, measuring principle generally all is based on NDIR (Non-Dispersive Infrared) spectral analysis technique (NDIR, Non-Dispersive Infrared), utilize tested gas to a certain waveband infrared absorption characteristic that has, select the infrared light of this specific band, make it to pass through gas sample, because of the relation of tested gas concentration in its light intensity attenuation amount and the sample meets the Beer-Lambert law, thereby can calculate the concentration of corresponding gas by the test light damping capacity. for example, breathe last CO
2Concentration monitor utilizes CO exactly
2Molecule optical absorption characteristics curve is at the remarkable absorption peak at 4.26 μ m places, and the infrared light by detecting this wavelength coverage calculates wherein CO by the damping capacity behind the air chamber
2The concentration of gas.
Usually, the thermoelectric type infrared eye is used for photo measure, can improve temperature resistance and float ability.Because of it is the device of a kind of interchange or transient response, must be modulated into impulse form by photometry and be surveyed.The conventional machinery mode is modulated at present, promptly, on the light path between infrared light supply and the detection air chamber, add a copped wave sheet with the given pace rotation with holes, light becomes light pulse signal behind this copped wave sheet, be used as carrier signal, this signal is modulated by the concentration signal of gas to be measured in the air chamber after passing and detecting air chamber, be converted to modulated voltage or current signal through infrared eye again. in this process, in order further to eliminate light source light-emitting efficiency, factors such as logical light rate of light path and temperature drift are to the influence of measurement result, system also will introduce one road carrier reference signal beyond described measured signal, any gas absorption is a certain waveband infrared in the not detected air chamber of general selection.With CO
2Gas concentration detects and is example, can embed the bandpass filter of two different centre wavelengths on the copped wave sheet, wherein, and logical centre wavelength of band and CO
2The passage of absorption peak 4.26 μ m unanimities is used to introduce CO
2The measurement of concetration signal, inconsistent another passage is introduced reference signal, and the carrier signal for last passage of looking is equal to. can be referring to U.S. Pat 4,522, and 204 and US 4,998,018.
The major defect of above-mentioned prior art is, owing to introduce the carrier wave reference channel, the structure of measuring sonde is comparatively complicated on the one hand, and cost is also higher; Because floating characteristic, the optical filter temperature of the optical filter of reference channel and signalling channel is difficult to be consistent on the other hand, and use the logical light rate variable quantity of latter two passage also different for a long time, cause not being equal to of carrier signal of reference channel signal and tested passage, be difficult to guarantee the measuring accuracy long-term stability.
The summary of the invention the technical problem to be solved in the present invention is to avoid above-mentioned the deficiencies in the prior art part and proposes a kind of method and device based on the mechanical modulation measure gas concentrations, can in the design of measuring sonde, need not consider the introducing problem of reference channel, thereby the structure of simplified measurement probe, reduce manufacturing cost, simultaneously, improve the long-time stability of measuring accuracy again.
The technical scheme that the present invention solve the technical problem employing is, a kind of method based on the mechanical modulation measure gas concentrations is provided, and comprises step
A. sample gas under study is extracted to the detection air chamber;
B. the copped wave motor drives the copped wave sheet and rotates with given pace under the effect of microprocessor unit, on the described copped wave sheet at least one through hole is arranged, make the light via through holes that sends from stable light source after, become light pulse, be used as carrier signal;
C. described carrier signal is passed the detection air chamber, is modulated by the concentration signal of specific gas in the air chamber;
D. the light signal after the modulation is converted into the voltage or the current signal of modulation successively through optical filter and photo-detector;
E. described voltage or current signal are sent to microprocessor unit behind signal processing circuit;
F. described microprocessor unit calculates the concentration of tested gas in the air chamber, or calculates the parameter that other is relevant with tested gas according to the described signal that receives;
Especially, at least one controllable gain amplifier is arranged in the described signal processing circuit, before described step a, also comprise the step of described controllable gain amplifier being carried out gain setting
1) reference gas is extracted to the detection air chamber; To voltage or current signal that d obtains, behind described amplification treatment circuit, be sent to microprocessor unit by above-mentioned steps b;
2) the microprocessor unit output regulation signal is given described controllable gain amplifier, and adjusts this signal magnitude, reaches setting value up to the amplitude that makes described signal processing circuit output signal;
3) microprocessor unit keeps the size of described conditioning signal, until assignment procedure next time.
Compared with prior art, this method when the witness mark gas to the gain control of amplifying circuit, can eliminate error because of the measuring-signal that the logical optical efficiency of light source light-emitting efficiency and light path changes, the difference of sensor responding ability and electronic devices and components is brought after the equipment long-term work, can also eliminate in the measuring process temperature drift to the influence that measurement result causes, be beneficial to the long-time stability that keep measuring accuracy.
The technical scheme that the present invention solve the technical problem employing also comprises, manufacture and design a kind of device based on the mechanical modulation measure gas concentrations, comprise that stable light source, detection air chamber reach the copped wave sheet that has through hole between the two, microprocessor unit connects the copped wave motor by circuit for controlling motor, makes it to drive described copped wave sheet rotation; Described detection air chamber rear end is aligned in sequence with optical filter, photo-detector, and the output of described photo-detector is sent to microprocessor unit through signal processing circuit; Described microprocessor unit comprises the analytical calculation unit, goes out the result according to the data computation that receives, and hands over its processing unit to export with the readable information form result; Described detection air chamber also has through hole to be communicated with draft tube and escape pipe respectively, is used for advancing and going out of sample gas under study; Especially, also comprise
Described signal processing circuit also comprises at least one controllable gain amplifier, and described controllable gain amplifier connects the conditioning signal from microprocessor unit.In addition, described draft tube can be communicated with three-way solenoid valve, and described three-way solenoid valve by under the effect of T-valve control circuit, can make the detection air chamber be communicated with reference gas or gas to be measured respectively at microprocessor unit.
Utilize apparatus of the present invention, can make the sensor probe structural design simple, the requirement of detector is also reduced greatly, and can effectively eliminate the influence that the optical assembly performance degradation brings in the test process, thereby improve the performance of equipment when saving equipment cost.
Description of drawings Fig. 1 is the theory diagram of gas concentration measuring apparatus of the present invention
Fig. 2 is the logical constitution block diagram of signal processing circuit 6 among Fig. 1
Fig. 3 is the physical circuit figure of described signal processing circuit
Fig. 4 is the physical circuit figure of apparatus for measuring concentration controller
Label wherein: 1---stable light source, 2---the copped wave motor, 3---the copped wave sheet, 4---detect air chamber, 5---photo-detector, 6---signal processing circuit, 7---microprocessor unit, 8---optical filter, 9---T-valve, 10---air pump, 11---electromotor control circuit, 12---the T-valve control circuit, 13---the flow rate detection circuit, 14---the air pump control circuit, 15---sampling pipe, 16---flow-limiting valve;
61---the logical amplifying circuit of band, 62---Hi-pass filter, 63---the controllable gain amplifying circuit, 64---low-pass filter, 65---the A/D translation circuit.
Below the embodiment, the most preferred embodiment shown in is described in further detail the present invention in conjunction with the accompanying drawings.
As shown in Figure 1, gas concentration measuring apparatus of the present invention, comprise stable light source 1, detect the copped wave sheet 3 that air chamber 4 reaches between the two and has through hole, described copped wave sheet 3 coaxial binding copped wave motor 2, microprocessor unit 7 is electrically connected described copped wave motor 2 by motor control unit 11, make it to drive described copped wave sheet 3 with the given pace rotation, thereby the light that light source 1 sends becomes the light pulse carrier signal with the corresponding certain frequency of its speed of rotation behind the process copped wave sheet 3; Described detection air chamber 4 rear ends are disposed with optical filter 8, photo-detector 5, the output of described photo-detector 5 is sent to microprocessor unit 7 through signal processing circuit 6, described microprocessor unit 7 comprises the analytical calculation unit, according to voltage that receives or current signal, calculate the concentration of tested gas in the air chamber, or calculate the parameter that other is relevant with tested gas; Described detection air chamber 4 also has through hole to be communicated with draft tube and escape pipe, is used for advancing and going out of tested gas sample.
Among Fig. 1, air-channel system comprises sampling pipe 15 and the T-valve 9, the flow-limiting valve 16 that are attached thereto and the air pump 10 that is attached thereto, described draft tube is communicated with this air-channel system by T-valve 9 and flow-limiting valve 16 respectively with escape pipe, to detecting in the air chamber 4, the exhausr port through flow-limiting valve 16, air pump 10 is discharged away sample gas then by continuous drawing through sampling pipe 15, T-valve 9.Described T-valve 9 can adopt the Electromagnetic Control mode, is electrically connected microprocessor unit 7 by T-valve control circuit 12, can be controlled its gating direction by microprocessor unit 7, makes to detect air chamber 4 or be communicated with reference gas, perhaps is communicated with gas to be measured.When adopting the air inlet source of manual type machinery control detection air chamber 4, described T-valve 9 can be saved, but is unfavorable for the The Automation Design of tester.Described flow-limiting valve 16 and air pump 10 are electrically connected microprocessor unit 7 by flow rate detection circuit 13 gentle pump control circuits 14 respectively; When the extracting gases sample, microprocessor unit 7 detects the real-time speed of exhaust by flow rate detection circuit 13, and passes through the speed of evacuation of air pump control circuit 14 control air pumps 10, reaches the purpose of stable sampling.
Light pulse carrier signal process by 3 outputs of copped wave sheet detects air chamber 4, because the part luminous energy is by certain corresponding gas absorption in the air chamber, the luminous energy passed through is changed with the concentration change of this gas, thereby produce by the light signal of the concentration parameter of described gas modulation, it is further converted to corresponding electrical modulation signal by photo-detector 5 behind bandpass filter 8. and described optical filter 8 can also be the photosensitive window that is embedded in photo-detector 5, forms incorporate photo-sensitive cell with it; Described photo-sensitive cell can also be combined into a probe assembly with described light source 1, copped wave motor 2, copped wave sheet 3, detection air chamber 4, and one realizes the conversion of gas concentration signal to electrical modulation signal.This assembly can also comprise signal processing circuit 6 as figure, with faint simulating signal is amplified, demodulation, even carry out being sent to microprocessor unit 7 after the analog to digital conversion.
When T-valve 9 made detection air chamber 4 select to be communicated with reference gases, entering the gas that detects air chamber 4 was the reference gas that the carrier wave light signal is not had absorption, and what photo-detector 5 was exported is carrier signal; Otherwise, when the air intake opening that detects air chamber 4 selects to be communicated with gas to be measured, photo-detector 5 outputs by the concentration parameter modulated carrier signal of certain specific gas.These two kinds of signals, the former is used for system's adjustment of device, and the latter is the analytic signal that device detected or monitored gas concentration.
For reaching effect of the present invention, make two kinds of signals can adopt same passage to handle, the structure that described signal processing circuit 6 adopts as shown in Figure 2 comprises at least one controllable gain amplifier 63, and this controllable gain amplifier 63 also connects the conditioning signal from microprocessor unit; Comprise that also the passband central frequency band consistent with carrier frequency leads to amplifying circuit 61, connect Hi-pass filter 62 thereafter, in order to eliminate the low frequency signal that temperature drift causes; The output of described Hi-pass filter 62 is sent to low-pass filter 64 again through controllable gain amplifier 63, and one of detection output and the corresponding level signal of gas concentration enter A/D translation circuit 65 again.The output of described controllable gain amplifier 63 also can directly be sent to microprocessor unit 7 through A/D translation circuit 65, by the function of microprocessor unit 7 by the method realization detection of software, detects and the corresponding signal of gas concentration.Described A/D translation circuit 65 can not be the part of signal processing circuit 6 also, but is integrated in a functional block in the microprocessor unit 7, and then described low-pass filter 64 output signals directly are sent to microprocessor unit 7.
Different needs according to the signal processing and amplifying, can also introduce one-level and above fixed gain amplifier between described controllable gain amplifier 63 and the low-pass filter 64, simultaneously in order to reduce the adverse effect that the circuit parameter drift brings, the output of controllable gain amplifier 63 can also be drawn one the tunnel in addition and be sent to microprocessor unit 7, when system introduced the reference channel signal, it act as the reference signal of adjusting amplifier 63 gain institute foundations.
Different gas has different optical absorption characteristics, changes optical source wavelength and adopts the corresponding photosensitive element, selects suitable reference source of the gas, and the method that just can utilize described device is at the different field testing gas concentration.With the end of the breathing in medical treatment CO
2Concentration monitor is an example, and monitoring target is the CO in the patient respiration gas
2Concentration is utilized CO
2To the absorption characteristic of 4.26 mum wavelength infrared lights, make stable light source 1 send 4.26 mum wavelength infrared lights.Generally get atmosphere during measurement and (look CO
2Concentration is zero) for reference gas, then can adopt measuring method of the present invention, comprise step
A. sample gas under study, promptly patient respiration gas is extracted to detecting air chamber 4 by air pump 10 under the control of microprocessor unit 7;
B. copped wave motor 2 drives copped wave sheet 3 with given pace rotation under the control of microprocessor unit 7, on the described copped wave sheet 3 at least one through hole is arranged, make the light via through holes that sends from stable light source 1 after, become light pulse, be used as carrier signal;
C. described carrier signal is passed and is detected air chamber 4, is modulated by the concentration signal of specific gas in the air chamber;
E. described voltage or current signal are sent to microprocessor unit 7 behind signal processing circuit 6;
F. described microprocessor unit 7 calculates CO in the air chamber according to the described signal that receives
2The concentration of gas, or calculate other and relevant parameter, as respiratory rate;
Wherein, the gain setting of controllable gain amplifier 63 carries out according to the following steps in the described signal processing circuit 6:
1) reference gas, promptly atmosphere is extracted to detecting air chamber 4 by air pump 10 under the effect of microprocessor unit 7; Obtain the voltage or the current signal of initial light intensity to d by above-mentioned steps b, behind described signal processing circuit 6, be sent to microprocessor unit 7;
2) microprocessor unit 7 output regulation signals are given described controllable gain amplifier 63, and adjust this signal magnitude, reach setting value up to the reference signal amplitude that makes described signal processing circuit 6 outputs;
3) microprocessor unit 7 keeps the size of described conditioning signal, until assignment procedure next time.
Before concentration monitor carried out surveying work, microprocessor unit 7 was earlier by above-mentioned steps 1) to 3) set the gain of controllable gain amplifier 63, to eliminate the difference of bringing because of the difference of amplifying circuit, the logical optical efficiency of light path and light source light-emitting efficiency; Then test breathing gas by above-mentioned steps a to f.In long-time measuring process, in order to eliminate the influence of amplifying circuit temperature drift to measurement result, described microprocessor unit 7 will be regularly by above-mentioned steps 1) to 3) adjust the gain of controllable gain amplifier 63, so that output signal keeps the long-time stability of measuring accuracy.Wherein, above-mentioned steps 1) and 2) described in the output of signal processing circuit 6 can be the output of same road signal, promptly, carry out different processing by microprocessor unit 7 again by low-pass filter 64 outputs; Also can be the two paths of signals of output separately, step 2) the described reference signal in is, the output of controllable gain amplifier 63 divides one the tunnel to be sent to microprocessor unit 7 through rectification in addition.
CO of the present invention
2Concentration monitor, the physical circuit figure that its signal processing circuit 6 adopts as shown in Figure 3.Wherein the logical amplifying circuit 61 of band comprises amplifier integrated circuit U8A and passive device C27, R39, C29, R40, R38, C28.Hi-pass filter 62 comprises that it is the first order amplifier of core that C32. controllable gain amplifying circuit 63 comprises with amplifier integrated circuit U8B, comprise digital regulation resistance U13 and R41, R44, R45, the part P2 mouth output of microprocessor unit 7 connects the digital end interface of described digital regulation resistance U13, can directly set, thereby change this grade Amplifier Gain by adjusting this resistance to the resistance of digital regulation resistance U13; The signal of amplifier output at the corresponding levels divides two-way, one the tunnel to be sent to amplifier integrated circuit U10B, U11A be the second level fixed gain amplifying circuit of core, the effect of D3, D4, D7, D8 makes this grade amplifier only export the above signal of zero level, it is the rectification circuit of core that another road is sent to amplifier integrated circuit U9A, produces reference signal C and is sent to microprocessor unit 7.In low-pass filter 64, the signal of described second level amplifying circuit output is sent to microprocessor unit 7 through test signal A of U10A detection output again through R54, C44 low-pass filtering filtering carrier wave.When introducing the signal of reference channel, microprocessor unit 7 is adjusted the resistance of digital regulation resistance U13, makes the C signal incoming level that receives reach default judgment value, and the level that writes down a-signal simultaneously is as the calibration basis; Keep the U13 resistance then, make the gain of controllable gain amplifying circuit 63 constant, introduce test signal,, judge the concentration change of test gas according to the variation of A level.In the concrete circuit diagram of apparatus for measuring concentration controller as shown in Figure 4, single-chip microcomputer U2 constitutes the control core of microprocessor unit 7, has comprised unit such as system software, data analysis computing unit, control signal generation.In the periphery of U2, U1 makes A/D conversion usefulness, described level signal A, C, from the Dpress signal of flow rate detection circuit 13,, and all be converted into digital signal from the MPump status signal of air pump control circuit 14 and be sent to U2 from the Mvalve status signal of T-valve control circuit 12; U2 is sent to the Valve control signal and the pwm control signal that is sent to air pump control circuit 14 of T-valve control circuit 12 according to system-computed judgement output simultaneously.
The used main components and parts inventory of the embodiment of the invention is as follows:
Sequence number component symbol model or parameter manufacturer information
1 U1 MAX158 Maxim
2 U2 AT89C51 Atmel
3 U5 NPC-1210 Novasensor
4 U6 TDA5145 PHILIPS
5 U8～U11 LT1013D TI
6 U13 MAX5402 Maxim
7 Q1 VN0605 SILICONIX
8 Q3 2N4403 MOTOROLA
9 Y1 11.0592M
10 D3 1N4148
11 C7 2.2μF
12 C28 1000pF
13 C32 0.47μF
14 E1 10μF?25V
15 R1 10KΩ
16 R2 100KΩ
17 R39 12.1KΩ
The electronic circuit of all Fig. 3, Fig. 4 and above-mentioned components and parts inventory, just an embodiment of this device does not limit to its physical circuit form.In actual use, prior art all has the electronic circuit of other form of employing to do equal the replacement. and as well known to those skilled in the art because of its genus, do not add detailed description at this.
Said method and device through medical clinical verification, have good measuring accuracy and measurement stability.
Claims (16)
1. the method based on the mechanical modulation measure gas concentrations comprises step
A. sample gas under study is extracted to and detects air chamber (4);
B. copped wave motor (2) drives copped wave sheet (3) and rotates with given pace under the effect of microprocessor unit (7), on the described copped wave sheet (3) at least one through hole is arranged, after making the light via through holes that sends from stable light source (1), become light pulse, be used as carrier signal;
C. described carrier signal is passed and is detected air chamber (4), is modulated by the concentration signal of specific gas in the air chamber;
D. the light signal after the modulation is converted into modulation voltage or current signal successively through optical filter (8) and photo-detector (5);
E. described voltage or current signal are sent to microprocessor unit (7) behind signal processing circuit (6);
F. described microprocessor unit (7) calculates the concentration of tested gas in the air chamber, or calculates the parameter that other is relevant with tested gas according to the described signal that receives;
It is characterized in that at least one controllable gain amplifier (63) is arranged in the described signal processing circuit (6), before described step a, also comprise,
Described controllable gain amplifier (63) is carried out the step of gain setting:
A. reference gas is extracted to and detects air chamber (4); Voltage or current signal by above-mentioned steps b obtains to d are sent to microprocessor unit (7) behind described amplification treatment circuit (6);
B. microprocessor unit (7) output regulation signal is given described controllable gain amplifier (63), and adjusts this signal magnitude, reaches setting value up to the amplitude that makes described signal processing circuit (6) output signal;
C. microprocessor unit (7) keeps the size of described conditioning signal, until assignment procedure next time.
2. the method based on the mechanical modulation measure gas concentrations according to claim 1 is characterized in that:
The described steps A that gain is set to controllable gain amplifier (63) is regularly carried out in long-time observation process to C.
3. the method based on the mechanical modulation measure gas concentrations according to claim 1 is characterized in that:
The air intake opening of described detection air chamber (4) is communicated with a three-way solenoid valve (9), microprocessor unit (7) can be controlled the communication direction of described T-valve (9) by T-valve control circuit (12), make among described step a and the A, detecting air chamber (4) can switch between connection gas to be measured and connection reference gas.
4. the method based on the mechanical modulation measure gas concentrations according to claim 1 is characterized in that, described signal processing circuit (6) comprises step to Signal Processing
A. the signal process from photo-detector (5) is the logical amplifying circuit (61) of band of centre frequency with the carrier wave, selects out useful signal;
B. described useful signal is through Hi-pass filter (62), is sent to controllable gain amplifier (63) after eliminating the low frequency signal that causes because of temperature drift.
5. the method based on the mechanical modulation measure gas concentrations according to claim 4 is characterized in that, described signal processing circuit (6) also comprises step to Signal Processing
C. the amplifying signal of controllable gain amplifier (63) output is through low-pass filter (64), and one and the corresponding level signal of gas concentration are exported in detection;
D. described level signal carries out exporting with digital signal form after the analog to digital conversion through A/D translation circuit (65).
6. according to claim 1,2 or 5 described methods, it is characterized in that based on the mechanical modulation measure gas concentrations,
Described controllable gain amplifier (63) is carried out among the step B of gain setting, the signal that the amplitude that act as of described signal processing circuit (6) output is judged, be that output by controllable gain amplifier (63) divides one the tunnel in addition through rectification, be sent to the another road signal of microprocessor unit (7) again.
7. device based on the mechanical modulation measure gas concentrations, comprise that stable light source (1), detection air chamber (4) reach the copped wave sheet (3) that has through hole between the two, microprocessor unit (7) connects copped wave motor (2) by electromotor control circuit (11), makes it to drive described copped wave sheet (3) rotation; Described detection air chamber (4) rear end is aligned in sequence with optical filter (8), photo-detector (5), and the output of described photo-detector (5) is sent to microprocessor unit (7) through signal processing circuit (6); Described microprocessor unit (7) comprises the analytical calculation unit, goes out the result according to the data computation that receives, and hands over its processing unit to export with the readable information form result; Described detection air chamber (4) also has through hole to be communicated with draft tube and escape pipe respectively, is used for advancing and going out of test gas sample; It is characterized in that,
Described signal processing circuit (6) also comprises at least one controllable gain amplifier (63), and described controllable gain amplifier connects the conditioning signal from microprocessor unit (7).
8. the device based on the mechanical modulation measure gas concentrations according to claim 7 is characterized in that:
Described device also comprises an air-channel system, described air-channel system comprises sampling pipe (15), flow-limiting valve (16) and the air pump (10) that is attached thereto, and the draft tube of described detection air chamber (4) is communicated with this air-channel system by sampling pipe (15) and flow-limiting valve (16) respectively with escape pipe; Described microprocessor unit (7) is electrically connected described flow-limiting valve (16) and air pump (10) by the gentle pump control circuit of flow rate detection circuit (13) (14) respectively, can make the velocity-stabilization that extracts test gas.
9. the device based on the mechanical modulation measure gas concentrations according to claim 7 is characterized in that:
Described air-channel system also comprises a three-way solenoid valve (9), be positioned between the draft tube of sampling pipe (15) and detection air chamber (4), microprocessor unit (7) is electrically connected described T-valve (9) by T-valve control circuit (12), can control its gating direction.
10. the device based on the mechanical modulation measure gas concentrations according to claim 7 is characterized in that:
Described optical filter (8) is embedded in the photosensitive window of photo-detector (5), forms incorporate photo-sensitive cell with it.
11. the device based on the mechanical modulation measure gas concentrations according to claim 10 is characterized in that:
Described incorporate photo-sensitive cell and light source (1), copped wave motor (2), copped wave sheet (3), detection air chamber (4) are combined into the probe assembly of an one, can realize that gas concentration signal arrives the conversion of electrical modulation signal.
12. the device based on the mechanical modulation measure gas concentrations according to claim 8 is characterized in that:
Described signal processing circuit (6) comprises that also the passband central frequency band consistent with carrier frequency leads to amplifying circuit (61), connects Hi-pass filter (62) thereafter, in order to eliminate the low frequency signal that temperature drift causes; Controllable gain amplifier (63) is sent in the output of described Hi-pass filter (62).
13. the device based on the mechanical modulation measure gas concentrations according to claim 12 is characterized in that:
Described signal processing circuit (6) also comprises low-pass filter (64), will be sent to microprocessor unit (7) from the signal of controllable gain amplifier (63) through detection output and the corresponding level signal of gas concentration.
14., it is characterized in that according to claim 7,12 or 13 described devices based on the mechanical modulation measure gas concentrations:
Described signal processing circuit (6) also comprises one-level A/D translation circuit (65), converts the simulating signal of desiring to be sent to microprocessor unit (7) to digital signal in advance.
15., it is characterized in that according to claim 7,13 described devices based on the mechanical modulation measure gas concentrations:
Described signal processing circuit (6) comprises that also another road of output is sent to the signal of microprocessor unit (7), is that output by controllable gain amplifier (63) divides one the tunnel to be sent to microprocessor unit (7) through rectification in addition.
16. the device based on the mechanical modulation measure gas concentrations according to claim 7 is characterized in that:
Described microprocessor unit (7) is with single-chip microcomputer design, described single-chip microcomputer or A/D translation circuit (65) placed outside the sheet, or be integrated in the sheet.
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| CN101153840B (en) * | 2006-09-29 | 2011-07-06 | 深圳迈瑞生物医疗电子股份有限公司 | Method and device for improving measurement precision of gas analyzer |
| CN101470075B (en) * | 2007-12-26 | 2012-04-11 | 深圳迈瑞生物医疗电子股份有限公司 | Gas concentration measuring apparatus |
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| CN103800984B (en) * | 2012-11-13 | 2017-04-19 | 深圳迈瑞生物医疗电子股份有限公司 | Valve module for controlling fluid flow |
| CN104697952B (en) * | 2015-03-23 | 2017-09-15 | 山东省科学院海洋仪器仪表研究所 | Device for the multiple gases in seawater to be carried out with Concentration Testing |
| US9945790B2 (en) * | 2015-08-05 | 2018-04-17 | Viavi Solutions Inc. | In-situ spectral process monitoring |
| CN109253982A (en) * | 2017-07-12 | 2019-01-22 | 上海通用检测技术研究所 | infrared leak detector |
| EP3994447A4 (en) * | 2019-08-23 | 2023-04-19 | Siemens Aktiengesellschaft | Gas analyzer |
| CN112649395B (en) * | 2019-10-10 | 2024-03-08 | 漳州英特捷自动化科技有限公司 | Online near-infrared moisture meter |
| CN113029949A (en) * | 2021-03-11 | 2021-06-25 | 南京格术光电技术有限公司 | Medium attenuation coefficient measuring device |
| CN114034660B (en) * | 2021-12-03 | 2024-03-08 | 福建美营自动化科技有限公司 | Gas detection system and method based on TDLAS |
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