AU2007237278B1 - Gas monitoring system - Google Patents
Gas monitoring system Download PDFInfo
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- AU2007237278B1 AU2007237278B1 AU2007237278A AU2007237278A AU2007237278B1 AU 2007237278 B1 AU2007237278 B1 AU 2007237278B1 AU 2007237278 A AU2007237278 A AU 2007237278A AU 2007237278 A AU2007237278 A AU 2007237278A AU 2007237278 B1 AU2007237278 B1 AU 2007237278B1
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- Prior art keywords
- gas
- laser
- measurement
- processing unit
- control unit
- Prior art date
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- 238000012544 monitoring process Methods 0.000 title claims description 17
- 239000007789 gas Substances 0.000 claims description 46
- 238000005259 measurement Methods 0.000 claims description 33
- 238000012545 processing Methods 0.000 claims description 28
- 239000000835 fiber Substances 0.000 claims description 23
- 238000004458 analytical method Methods 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 7
- 230000000694 effects Effects 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims description 7
- 238000010304 firing Methods 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 4
- 230000003993 interaction Effects 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 230000005855 radiation Effects 0.000 claims description 3
- 238000013500 data storage Methods 0.000 claims description 2
- 230000007257 malfunction Effects 0.000 claims description 2
- 238000004148 unit process Methods 0.000 claims description 2
- 230000000007 visual effect Effects 0.000 claims description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- 231100001261 hazardous Toxicity 0.000 description 5
- 239000003921 oil Substances 0.000 description 5
- 238000004880 explosion Methods 0.000 description 3
- 239000002360 explosive Substances 0.000 description 3
- 239000000969 carrier Substances 0.000 description 2
- 239000012190 activator Substances 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000004868 gas analysis Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/268—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light using optical fibres
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/342—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells the sensed object being the obturating part
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/08—Optical fibres; light guides
- G01N2201/0826—Fibre array at source, distributing
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/08—Optical fibres; light guides
- G01N2201/084—Fibres for remote transmission
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Description
AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Gas monitoring system The following statement is a full description of this invention, including the best method of performing known to me/us: 2 Field of the Invention This invention relates to a gas monitoring system for the detection and measurement, at multi or single point sites, of the concentration of one or more potentially hazardous target gases. This system can be used in various sectors 5 of industry, typically for marine use e.g. with oil tankers: LNG and LPG carriers, for use in the petrochemical industry e.g. at oil refinery sites, for use in the monitoring at landfill sites, for use on oil or gas production platforms, drilling rigs, and for use in oil and gas storage sites. 1o Background of the Invention [Mere reference to background art herein should not be construed as an admission that such art constitutes common general knowledge in relation to the invention.] A standard safety requirement in marine crude oil tankers, or LPG or LNG 15 carriers, is the provision of a methane monitoring system to provide information as to a potentially hazardous methane concentration. Currently piping is provided up to 36 location points on a vessel e.g. at ballast spaces, where information as to a methane presence and/or concentration is required. The piping extends to analytical equipment located remotely, often in an explosion 20 proof housing, with individual pipes interrogated on a routine basis e.g. by connection to a pump; whereby a gas sample may be drawn from a selected remote location along the piping to the analytical equipment. Apart from the cost of installing such piping, time delays are encountered in providing a sample from a remote location on a tanker sequentially, while piping inspection and 25 maintenance add further costs, as any leakage produces unreliable results and causes potential safety problems.
3 The above described system operates basically on the pumping of a sample back to a remote, safe location. An alternative system is to provide a sensor at the location where monitoring is required, at the end of a wire extending back to data processing 5 equipment at a remote safe location. The sensor may be placed in a dirty atmosphere that may be explosive; it will consist of electronic circuitry and a sensor head. The electronics requires power to operate and has to transmit that signal back to the processing equipment. The presence of this circuitry within the explosive atmosphere is itself a hazard. For this to be present in such an 10 explosive atmosphere a safety certificate is necessary and suitable equipment has limited availability. The other potential problem is the breakage of the wire from the sensor and total loss of signal from the sensor and whatever potential explosion effect it may bring. There are numerous types of gas sensors for flammable gas including the 15 use of light at or near the infra-red frequency, being based on the principle that different gasses absorb 1.R. light at different frequencies. Object of the Invention A basic object of the invention is the provision of an improved multi or 20 single point monitoring system that will operate safely and reliably in all areas including zone 0 or 1. Summary of the Invention According to the present invention, there is provided a multi or single 25 point gas monitoring system utilizing the I.R absorbing properties of the target 4 gas, comprising of a control unit, provided at a remote, safe location, and measurement cells, the system further comprising: (a) at least one laser tuned to emit radiation appropriate to the target gas and at a wavelength not susceptible to effects due to changing temperatures at the 5 measurement cells; (b) control means for firing the laser to emit light within a selected range of frequencies around the appropriate IR frequency; (c) fibre optic cabling extending from the laser to an optical beam splitter; (d) a plurality of measurement cells each located at a point where monitoring 10 is required, and adapted to be subjected to a gas sample potentially including the target gas; (e) a corresponding plurality of fibre optic cables extending from the beam splitter to each measurement cell; (f) one photo detector for each measurement cell; 15 (g) fibre optic cabling, extending from each measurement/reference cell to the photo detector(s) to calculate the light levels from the measuring, cells; (h) a fibre optic cable from the optical beam splitter to a photo detector to provide 20 a light reference point; (i) means to process an output signal from the photo detectors, converting the signal into a gas concentration after removing any effects of temperature and background signal noise; and (j) general functionality control means; 5 whereby the system indicates the concentration of gas detected at each measurement cell and initiates an alarm signal in the event of detection of a target gas concentration outside a predetermined acceptable range. 5 Advantages of the Invention Considering any installation of the gas monitoring system in accordance with the invention the advantages are five fold: (i) the need for a piping system or electrical cables or associated attendant costs are avoided; 10 (ii) the delay in analysing a sample is also eliminated, for the use of fibre optic cabling, results in virtually instantaneous monitoring; (iii) any damage to, or severing of, the fibre optics cables provides no safety risk; (iv) the use of fibre optic cable eliminates electro-mechanical interference 15 associated with electrical cables; (v) the problem of explosions is avoided because at the measuring point the only signal being utilised is that of light. The system is therefore electrically safe and can be used in a zone 0 hazardous area. 20 Preferred Features of the Invention The optical splitter splits an output from the laser into all of the multi/single point site(s) at which monitoring is required. The control unit incorporates a laser reference photodiode connected by a fibre optic cable to the splitter. 25 The light levels are monitored using photo detectors.
6 The photo detectors are, together with basic signal processing circuitry, on one electronic board. Each measurement cell consists of an integral collimator allowing interaction between the gas being monitored and the light from the laser. 5 The control unit incorporates a gas reference cell, for wavelength checking, connected by a fibre optic cable to the splitter and to its respective photodiode. The control unit incorporates multiple lasers, being either identically tuned lasers, with the second laser simply being a backup to obviate the effect of any 1o malfunction of the first laser, or the other differently tuned lasers, if the detection of different target gases is a requirement. The control unit incorporates a processing unit that performs light level value processing and information analysis processing. The processing unit processes the light levels from the laser reference 15 and measurement point and these values are plotted, a curve fitted and the fitting parameters used to calculate the gas concentration, and the gas concentration will be compared with pre-set alarm concentration levels and used to energise/de-energise relays as appropriate. The processing unit controls functions that interrogate the measurement 20 cells in a programmed sequence. A keypad and a visual display are connected to processing unit. The following parameters are changeable in the field, using the keypad and the display: 1. Alarm set points. 25 2. Skip of one-or a group of measurement cells, including calibration check. 3. Monitor a particular location continuously.
7 4. Go to a particular analysis location. 5. Perform a calibration check. 6. Establish data storage frequency on the processing unit. 7. Calibrate each 4-20 mA output. 5 The control unit incorporates a measurement cell for calibration check purposes connected by a fibre optic cable to the splitter and to its respective photodiode. The processing unit is set up from parameters downloaded from a computer e.g. a laptop. 10 The laptop will also allow a history of gas concentrations to be downloaded from processing unit for further analysis. The general functionality control means also comprises basically a proprietary microprocessor running software to control firing of the lasers, to analyse the gas concentration figures, to raise an alarm etc. 15 The system allows actions to be taken from these alarms by way of an internal relay or for the alarms to be cancelled or acknowledged. The system also allows for these alarms and concentrations to be transmitted to an external third party processing unit which can then process or display the information as required. 20 The control unit is housing in an industrial enclosures. Brief Description of the Drawings Figure 1 illustrates diagrammatically one example of multi-point target gas analysis/detection system in accordance with the invention; and 25 Figure 2 details a measurement cell of Figure 1.
8 Detailed Description of an Embodiment of the Invention A multi- or single-point gas monitoring system 1 utilizes the I.R. absorbing properties of the target gas, and comprises a control unit 2 provided at a remote, non-hazardous safe location 3, and a plurality of measurement cells 4A, 4B, 4C 5 etc located in, or at, a potentially hazardous measurement zone 5, typically a tank of an oil tanker. The control unit 1 comprises a first laser 6A tuned to emit radiation appropriate to the target gas, typically methane, and second and third option lasers 6B, 6C, each laser being provided with a control means 7A, 7B, 7C for io firing the associated laser 6A, 6B, 6C to emit light within a selected range of frequencies around the appropriate l.R. frequency. Fibre optic cabling 8A, 8B, 8C extends from the lasers 6A, 6B, 6C to an optical beam splitter 9, which splits and output from the or each laser 6A, 6B, 6C for delivery, via fibre optic cables 1 1A, 11 B, 11C to whatever number of individual measurement cells are required, 15 three only being illustrated at 4A, 4B, 4C, each measurement cell incorporating a photo detector. Further fibre optic cables 11, 12 and 13 extend from the beam splitter 9 respectively to a photo detector 14, a calibration measurement cell 15 and a gas reference measurement cell 16 for wave length checking. The photo detector 14 is mounted on an electronic light processing board 17, which also 20 carries a calibration photo detector 18 connected via a fibre optic cable 12A to the cell 15, a gas reference photo detector 19 connected via a fibre optic cable 13A to the cell 16. Fibre optic cables 20A, 20B, 20C from the cells 4A, 4B, 4C respectively convey outputs to photo detectors 21A, 21B, 21C respectively also mounted on 25 the board 17, whilst communication between the six photo detectors of the board 17 and a processing unit 22 using electronic signals along wire 23, the 9 processing unit 22 processing output signals from the six photo detectors of the board 17 and simply comprises a proprietary microprocessor running appropriate software, whereby the system 1 is capable of indicating the concentration of a target gas detected at each measurement point and to initiate an alarm signal in 5 the even of detection of a concentration outside a predetermined acceptable range. As shown in Figure 2, each measurement cell 4A, 4B, 4C consists of an integral collimator 23 and 24, allowing interaction between the target gas being monitored and the light from the laser. The collimators 23 and 24 are aligned lo using an alignment groove 25. Field outputs from the processing unit 22 are not only to activators and audible alarm signals, but also to a laptop, a printer etc, whilst the general functionality control means consists of industry-standard components organized within the competence of any instrumentation engineer. 15 The foregoing embodiment is intended to be illustrative of the invention, without limiting the scope thereof. The invention is capable of being practised with various modifications and additions as will readily occur to those skilled in the art. Accordingly, it is to be understood that the scope of the invention is not to be limited to the exact construction and operation described and illustrated, but 20 only by the following claims. Throughout this specification, including the claims, where the context permits, the term "comprise" and variants thereof such as "comprises" or "comprising" are to be interpreted as including the stated integer or integers without necessarily excluding any other integers. 25
Claims (18)
1. A multi or single point gas monitoring system utilizing the L.R absorbing properties of the target gas, comprising of a control unit, provided at a remote, safe location, the system further comprising: 5 (a) at least one laser tuned to emit radiation appropriate to the target gas and at a wavelength not susceptible to effects due to changing temperatures at the measurement cells; (b) control means for firing the laser(s) to emit light within a selected range of frequencies around the appropriate IR frequency; 10 (c) fibre optic cabling extending from the laser(s) to an optical beam splitter; (d) a plurality of measurement cells each located at a point where monitoring is required, and adapted to be subjected to a gas sample potentially including the target gas; (e) a corresponding plurality of fibre optic cables extending from the beam 15 splitter to each measurement cell; (f) one photo detector for each measurement cell; (g) fibre optic cabling, extending from each measurement/reference cell to the photo detector(s) to calculate the light levels from the measuring, cells; 20 (h) a fibre optic cable from the optical beam splitter to a photo detector to provide a light reference point; (i) means to process an output signal from the photo detectors, converting the signal into a gas concentration after removing any effects of temperature and 25 background signal noise; and (j) general functionality control means; ll whereby the system indicates the concentration of gas detected at each measurement point and initiates an alarm signal in the event of detection of a target gas concentration outside a predetermined acceptable range. 5
2. A system as claimed in Claim 1, wherein the optical splitter splits an output from the laser into all of the multi/single point site(s) at which monitoring is required.
3. A system as claimed in Claim 1 or Claim 2, wherein the control unit 10 incorporates a laser reference photodiode connected by a fibre optic cable to the splitter.
4. A system as claimed in any preceding claim, wherein the light levels are monitored using photo detectors. 15
5. A system as claimed in Claim 4, wherein the photo detectors are, together with basic signal processing circuitry, on one electronic board.
6. A system as claimed in any preceding claim, wherein each measurement 20 cell consists of an integral collimator allowing interaction between the gas being monitored and the light from the laser.
7. A system as claimed in any preceding claim, wherein the control unit incorporates a gas reference cell, for wavelength checking, connected by a fibre 25 optic cable to the splitter and to its respective photodiode. 12
8. A system as claimed in any preceding claim, wherein the control unit incorporates multiple lasers, being either identically tuned lasers, with the second laser simply being a backup to obviate the effect of any malfunction of the first laser, or the other differently tuned lasers, if the detection of different 5 target gases is a requirement.
9. A system as claimed in any preceding claim, wherein the control unit incorporates a processing unit that performs light level value processing and information analysis processing. 10
10. A system as claimed in Claim 9, wherein the processing unit processes the light levels from the laser reference and measurement point and these values are plotted, a curve fitted and the fitting parameters used to calculate the gas concentration, and the gas concentration will be compared with pre-set 15 alarm concentration levels and used to energise/de-energise relays as appropriate.
11. A system as claimed in Claim 9 or Claim 10, wherein the processing unit controls functions that interrogate the measurement cells in a programmed 20 sequence.
12 A system as claimed in any preceding claim, wherein a keypad and a visual display are connected to processing unit. 25
13. A system as claimed in Claim 12, wherein the following parameters are changeable in the field, using the keypad and the display:- 13 1. Alarm set points. 2. Skip of one-or a group of measurement cells, including calibration check. 3. Monitor a particular location continuously. 4. Go to a particular analysis location. 5 5. Perform a calibration check. 6. Establish data storage frequency on the processing unit. 7. Calibrate each 4-20 mA output.
14. A system as claimed in any preceding claim, wherein the control unit 1o incorporates a measurement cell for calibration check purposes connected by a fibre optic cable to the splitter and to its respective photodiode.
15. A system as claimed in Claim 9, and any claim appended thereto, wherein the processing unit is set up from parameters downloaded from a 15 computer e.g. a laptop.
16. A system as claimed in Claim 15, wherein the laptop will also allow a history of gas concentrations to be downloaded from processing unit for further analysis. 20
17. A system as claimed in any preceding claim, wherein the control unit is housing in an industrial enclosures.
18. A multi or single point gas monitoring system substantially as herein 25 before described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2007237278A AU2007237278B1 (en) | 2007-11-30 | 2007-11-30 | Gas monitoring system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2007237278A AU2007237278B1 (en) | 2007-11-30 | 2007-11-30 | Gas monitoring system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2007237278B1 true AU2007237278B1 (en) | 2009-05-21 |
Family
ID=40671601
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2007237278A Ceased AU2007237278B1 (en) | 2007-11-30 | 2007-11-30 | Gas monitoring system |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU2007237278B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107884363A (en) * | 2017-10-17 | 2018-04-06 | 中国矿业大学(北京) | A kind of laser mine gas method of telemetering based on machine vision technique |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5026991A (en) * | 1989-09-20 | 1991-06-25 | Spectral Sciences, Inc. | Gaseous species absorption monitor |
| US5748325A (en) * | 1995-09-11 | 1998-05-05 | Tulip; John | Gas detector for plural target zones |
| US6150661A (en) * | 1993-04-16 | 2000-11-21 | Bruce W. McCaul | Gas spectroscopy |
-
2007
- 2007-11-30 AU AU2007237278A patent/AU2007237278B1/en not_active Ceased
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5026991A (en) * | 1989-09-20 | 1991-06-25 | Spectral Sciences, Inc. | Gaseous species absorption monitor |
| US6150661A (en) * | 1993-04-16 | 2000-11-21 | Bruce W. McCaul | Gas spectroscopy |
| US5748325A (en) * | 1995-09-11 | 1998-05-05 | Tulip; John | Gas detector for plural target zones |
Non-Patent Citations (2)
| Title |
|---|
| Gerald R. Beaudoin, 'Fiber optic based tunable diode laser gas detector', Master of Science Thesis, University of Alberta, Retrieved from the Internet: URL: http://www.collectionscanada.gc.ca/obj/s4/f2/dsk1/tape4/PQDD0013/MQ60101.pdf * |
| Richter et al. 'Development of an automated diode laser based multi-component gas sensor', Applied Optics, Vol 39, No 24, 20 August 2000, Pages 4444 - 4450 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107884363A (en) * | 2017-10-17 | 2018-04-06 | 中国矿业大学(北京) | A kind of laser mine gas method of telemetering based on machine vision technique |
| CN107884363B (en) * | 2017-10-17 | 2023-10-24 | 中国矿业大学(北京) | Laser mine gas telemetry method based on machine vision technology |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FGA | Letters patent sealed or granted (standard patent) | ||
| MK14 | Patent ceased section 143(a) (annual fees not paid) or expired |