GB2233087A - Apparatus for monitoring a gas or a flame - Google Patents
Apparatus for monitoring a gas or a flame Download PDFInfo
- Publication number
- GB2233087A GB2233087A GB9011843A GB9011843A GB2233087A GB 2233087 A GB2233087 A GB 2233087A GB 9011843 A GB9011843 A GB 9011843A GB 9011843 A GB9011843 A GB 9011843A GB 2233087 A GB2233087 A GB 2233087A
- Authority
- GB
- United Kingdom
- Prior art keywords
- gas
- modulator means
- modulator
- light source
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000012544 monitoring process Methods 0.000 title claims abstract description 9
- 239000013307 optical fiber Substances 0.000 claims abstract description 18
- 230000003287 optical effect Effects 0.000 claims abstract description 11
- 239000013074 reference sample Substances 0.000 claims abstract description 5
- 238000010521 absorption reaction Methods 0.000 claims description 30
- 238000004611 spectroscopical analysis Methods 0.000 claims description 13
- 230000005684 electric field Effects 0.000 claims description 12
- 230000003595 spectral effect Effects 0.000 claims description 4
- 230000005699 Stark effect Effects 0.000 claims description 3
- 230000005274 electronic transitions Effects 0.000 claims description 3
- 230000005281 excited state Effects 0.000 claims description 3
- 239000000523 sample Substances 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 67
- 238000000034 method Methods 0.000 description 8
- 239000000835 fiber Substances 0.000 description 6
- 230000001419 dependent effect Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002245 particle Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- 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
- G01N21/1717—Systems in which incident light is modified in accordance with the properties of the material investigated with a modulation of one or more physical properties of the sample during the optical investigation, e.g. electro-reflectance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/58—Radiation pyrometry, e.g. infrared or optical thermometry using absorption; using extinction effect
-
- 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
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
- G01J3/433—Modulation spectrometry; Derivative spectrometry
- G01J2003/4336—Modulation spectrometry; Derivative spectrometry by magnetic modulation, e.g. Zeeman effect
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)
Abstract
Apparatus (12) for monitoring a gas, which apparatus (12) comprises a light source (4), detector means (10) for receiving an optical signal from the light source (4), sensor means (6) which contains a sample of the gas to be monitored, modulator means (8) which contains a reference sample of the gas to be monitored, and an optical fibre light guidance system (16, 20) for guiding light between the light source (4) and the sensor means (6) and between the sensor means (6) and the detector means (10), and the apparatus (12) being such that the optical signal received by the detector means (10) is modulated with respect to the concentration of the gas to be detected by the sensor means (6). In another embodiment an optical fibre guides light from a flame being monitored to a modulator means and thence to a detector means, especially for determining the flame temperature. <IMAGE>
Description
APPARATUS FOR MONITORING A GAS
This invention relates to apparatus for monitoring a gas.
More specifically, the present invention provides apparatus for monitoring a gas, which apparatus comprises a light source, detector means for receiving an optical signal from the light source, sensor means for sensing the gas to be monitored, modulator means which contains a reference sample of the gas to be monitored, and an optical fibre light guidance system for guiding light between the light source and the sensor means and between the sensor means and the detector means, and the apparatus being such that the optical signal received by the detector means is modulated with respect to the concentration of gas to be detected by the sensor means.
The apparatus of the present invention will usually be used for detecting the presence of the gas, or for measuring the concentration of the gas.
The modulator means may be provided at any position in the optical fibre light guidance system between the light source and the detector means. The reference sample of the gas to be monitored will usually be a reference sample of known concentration.
It is already known to perform gas sensing by the use of a technique called pressure modulation spectroscopy. With such a known technique, sensing means and modulation means are employed and light from a light source is partially absorbed in the sensing means, according to the particular absorption lines present and the gas concentration in the modulator means. The modulator means is capable of loss modulation.
In the known gas sensing method, the subsequent absorption of the gas in the modulator means is modified by changing the pressure of the gas in the modulator means. This has the effect of modulating the intensity and spectral absorption of the absorption lines in the modulator means. However, the overall effect on the light intensity at the detector means is dependent on the extent to which the sensor means has already caused absorption of the light within its own absorption bands. Hence the relative modulation of the intensity of the detected signal is dependent on the extent of the absorption in the sensor means, which in turn is dependent on the concentration of gas detected, and of course on the length of the sensor means. This method of gas sensing by pressure modulation spectroscopy has been known for approximately twenty years.
In addition, there has been interest in a number of optical fibre remote gas sensors over a period of approximately ten years. Despite the fact that there are many advantages to be gained in combining the attributes of a modulated sample gas cell method of gas detection such as is afforded by pressure modulation spectroscopy, with optical fibre systems, this has not previously been effected. Since the persons known to have interest in the above mentioned optical fibre remote gas sensors are known to be persons of considerable technical capability, and since the above mentioned known conventional gas sensing by pressure modulation spectroscopy has been known for approximately twenty years, it must be concluded that the combination afforded by the present invention is both significant and inventive.
In the present invention, several different types of modulator means may be employed.
In a first embodiment of the invention, the modulator means is a pressure modulator means which is such that it operates by pressure modulation spectroscopy.
This type of pressure modulator means is advantageous in that pressure modulation spectroscopy enables the easy attainment of a perfect matched filter for gas detection, namely by using a sample of the gas to be detected as a reference. The entire apparatus can be made to be very flexible in that the apparatus can be modified for specific gases to be monitored simply by changing the gas in the modulator means so that it is the same as the gas to be monitored.
Furthermore, the rejection of the apparatus to other gases is high since the gas lines are generally both narrow in band width and numerous, so that a significant overlap of even a single line between lines of an interfering impurity species of gas and lines of the gas to be monitored is highly unlikely, and multiple line overlap is extremely improbable.
The modulator means may also be such that it does not use the above mentioned known gas sensing technique of pressure modulation spectroscopy. Thus, in a second embodiment of the invention, the modulator means is a pressure modulator means which is such that it operates by focusing acoustic waves to produce an increased fractional pressure modulation of the gas in the focused acoustic wave region. The focusing may be substantially complete focusing or it may be partial focusing.
Ih a third embodiment of the invention, the modulator means is a velocity modulator means which operates to cause Doppler shifting of the absorption of the gas in the velocity modulator means with respect to the detector means.
The velocity modulation may be achieved by at least one acoustic transducer coupled to the gas in the velocity modulator means. Usually, there will be at least two of the acoustic transducers.
The velocity modulation may alternatively be achieved by focused acoustic waves for increasing the velocity of the gas molecules and hence the Doppler shift of the absorption lines of gas within the modulator means.
In a fourth embodiment of the invention, the modulator means is a time varying magnetic field modulator means for modulating the absorption of the gas in the modulator means, relative to the absorption of the gas in the sensor means, the time varying magnetic field modulator means being such that it operates by applying a time varying magnetic field to the gas in the modulator means.
The direction of the applied magnetic field may be substantially aligned with the direction of propagation of light through the modulator means.
The modulation using the time varying magnetic field may be via the well known Zeeman spitting of electronic absorption lines. The modulation may involve sideways splitting into two lines of an electronic absorption line.
In a fifth embodiment of the invention, the modulator means is a time varying electric field modulator means for modulating the absorption of the gas in the modulator means, relative to the absorption of the gas in the sensor means, the time varying electric field modulator means being such that it operates by applying a time varying electric field to the gas in the modulator means.
The modulation with the time varying electric field modulator means may operate due to such well known effects as the Stark effect, or due to movement of polar gas molecules to align with the applied electric field.
Other modulation methods for modulating the gas absorption may be employed. In the above mentioned novel methods of gas absorption modulation, it is not essential that the amplitude of the absorption lines is modulated, as a frequency shifting of the absorption lines, away from the frequencies of those of the gas in the sensing means, will also suffice to cause the desired intensity modulation.
Advantageously, the optical fibre light guidance system includes a reference path which is from the light source to the detector means for the light source and which bypasses the sensor means, the apparatus being such that light from the light source is split into two separate optical paths which are directed through the modulator means, in order to reference any attenuation changes due to the modulator means itself against those from the reference path obtained directly from the light source.
The sensor means may be a sensor cell or a gas sensing region, The gas sensing region may just be an air space.
The modulator means will usually be a modulator cell.
The apparatus of the present invention may be such that it monitors a hot gas which emits light. More specifically, the hot gas, for example in a flame, may emit light due to relaxation of excited states, for example vibrational, rotational or electronic transitions.
The modulator means, for example the pressure modulator means, the time varying magnetic field using
Zeeman splitting of electronic absorption lines, or the time varying electric field modulator means using the Stark effect, may be used to detect the intensity of lines from the degree of modulation of the signal, detected from the hot gas, for example in the flame.
The detection may be by detector means, when the light or a portion of the light collected from the hot gas is guided, via a fibre optic cable and via the modulator means, to a detector means.
If desired, the spectral distribution of the lines detected may be monitored, using a frequencyswept optical fibre in front of the detector means, in order to deduce the temperature of the hot gas, for example in the flame.
Embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings in which:
Figure 1 shows apparatus for performing gas sensing by a known conventional technique of pressure modulating spectroscopy;
Figure 2 shows first apparatus of the present invention;
Figure 3 shows second apparatus of the present invention; and
Figure 4 shows third apparatus of the present invention.
Referring to Figure 1, there is shown known apparatus 2 for effecting gas sensing by conventional pressure modulation spectroscopy. The apparatus 2 comprises a light source 4 which directs light to sensor means in the form of a sensor cell 6. The sensor cell 6 contain gas to be detected. Light from the light source 4 further passes to modulator means in the form of a pressure modulator cell 8 which is such that it operates by pressure modulation spectroscopy. The light then passes to detector means 10 for being detected.
Referring now to Figure 2, there is shown first apparatus 12 which is for monitoring a gas and which is in accordance with the present invention. For ease of comparison and understanding, similar parts as in Figure 1 have been given the same reference numerals. The apparatus 12 forms a fibre optic remoted gas modulation gas detector. Light from the light source 4 is shown as passing- through launching optics 14, through an optical fibre waveguide 16 to the sensor cell 6. The sensor cell 6 may alternatively be a sensor region which may just be formed by free space. Thus the sensor cell 6 in Figure 2 has been indicated by broken lines.
The sensor cell 6 is associated with collimation and re-focusing optics 18 as shown. Light from the collimation and re-focusing optics 18 then passes along an optical fibre waveguide 20 to the modulator cell 8 which is a gas absorption modulator cell. The modulator cell 8 is associated with collimation and re-focusing optics 22 as shown. Light from the collimation and re-focusing optics 22 then passes to the detector means 10.
It will be seen that the optic fibre waveguides 16,20 form an optical fibre light guidance system for guiding light between the light source 4 and the sensor means in the form of the sensor cell 6 or the sensing region 6, and between the sensor means and the detector means 10. The apparatus 12 operates such that the optical signal received by the detector means 10 is modulated with respect to the concentration of gas to be detected by the sensor means in the form of the sensor cell 6 or the sensing region 6. The apparatus 12 may be employed for detecting the gas or for measuring the gas.
Referring now to Figure 3, similar parts as in Figure 2 have been given the same reference numerals for ease of comparison and understanding and their precise construction and operation will not again be given. In Figure 3, the apparatus 12 forms a fibre optic remoted gas sensor with a compensation/reference path via a direct route from the light source 4. More specifically, it will be seen that there is provided an optical fibre reference path 24 which is from the light source 4 to the detector means 10 for the light source, and which bypasses the sensor means 6.The apparatus 12 shown in Figure 3 is such that light from the light source 4 is split into two separate optical signals as shown which are directed through the modulator means 8, in order to reference any attenuation changes due to the modulator means 8 itself against those from the reference path 24 obtained directly from the light source 4. Light passing along the reference path 24 is detected by a second detector means 26 as shown.
Referring now to Figure 4, there is shown apparatus 12 which is for monitoring an incandescent gas in the form of a flame 4. Light from the flame 4 passes along an optical fibre waveguide 16 to a modulator cell 8. The modulator cell 8 is associated with collimation and re-forcusing optics 22 as shown.
Light from the collimation and re-focusing optics 22 then passes to a detector means 10.
The flame emits light due to relaxation of excited states, via vibrational, rotational or electronic transitions. This emited light is detected by the modulator cell 8, using pressure modulation spectroscopy which detects the intensity of lines from the degree of modulation of the signal, detected from the flame.
The light source 4 and the sensing means 6 in
Figures 2 and 3 are thus constituted by the hot gases within the flame 4 in Figure 4. The flame 4 may constitute a light source alone which emits light in spectral lines in the same region when a cold gas might absorb in Figures 2 and 3 or, alternatively, incandescent particles such as hot carbon within the flame 4 may act as broadband light sources which are subsequently subject to narrow band absorption lines causing loss of energy at certain parts of the spectrum corresponding to the absorption lines of gases in the path from the hot particles to the collecting optical fibre or fibres.
It is to be appreciated that the embodiments of the invention described above with reference to the accompanying drawings have been given by way of example only and that modifications may be effected.
Thus, for example, the modulator means in the form of the modulator cell 8 may be provided at any position in the optical fibre light guidance system between the light source 4 and the detector means 10 or 10,26.
In addition, with the use of directional couplers in the fibre optic path, a bi-directional link in a single fibre may be made to a cell means which is retroreflective in nature. For example, at the far side of the cell means, a retro-reflective prism or lens/mirror arrangement of well known means may be incorporated.
Further, although the modulator means is preferably a pressure modulator means which operates by pressure modulation spectroscopy, the modulator means may alternatively be a pressure modulator means which operates by focusing acoustic waves, or it may be a velocity modulator means, a time varying magnetic field modulator means or a time varying electric field modulator means a The present invention also extends to the described and/or illustrated features, taken separately or in any combination whatsoever.
Claims (19)
1. Apparatus for monitoring a gas, which apparatus comprises a light source, detector means for receiving an optical signal from the light source, sensor means for sensing the gas to be monitored, modulator means which contains a reference sample of the gas to be monitored, and an optical fibre light guidance system for guiding light between the light source and the sensor means and between the sensor means and the detector means, and the apparatus being such that the optical signal received by the detector means is modulated with respect to the concentration of gas to be detected by the sensor means.
2. Apparatus according to claim 1 in which the modulator means is a pressure modulator means which is such that it operates by pressure modulation spectroscopy.
7. Apparatus according to claim 1 in which the modulator means is a pressure modulator means which is such that it operates by focusing acoustic waves to produce an increased fractional pressure modulation of the gas in the focused acoustic wave region.
4. Apparatus according to claim 1 in which the modulator means is a velocity modulator means which operates to cause Doppler shifting of the absorption of the gas in the velocity modulator means with respect to the detector means.
5. Apparatus according to claim 4 in which the velocity modulation is achieved by at least one acoustic transducer coupled to the gas in the velocity modulator means
6. Apparatus according to claim 5 in which there are at least two of the acoustic transducers.
7. Apparatus according to claim 4 in which the velocity modulation is achieved by focused acoustic waves for increasing the velocity of the gas modules and hence the Doppler shift of the absorption lines of gas within the modulator means.
8. Apparatus according to claim 1 in which the modulator means is a time varying magnetic field modulator means for modulating the absorption of the gas in the modulator means, relative to the absorption of gas in the sensor means, the time varying magnetic field modulator means being such that it operates by applying a time varying magnetic field to the gas in the modulator means.
9. Apparatus according to claim 8 in which the direction of the applied magnetic field is substantially aligned with the direction of propagation of light through the modulator means.
10. Apparatus according to claim 8 in which the modulation using the time varying magnetic field is via
Zeeman splitting of electronic absorption lines.
11. Apparatus according to claim 1 in which the modulator means is a time varying electric field modulator means for modulating the absorption of the gas in the modulator means, relative to the absorption of the gas in the sensor means, the time varying electric field modulator means being such that it operates by applying a time varying electric field to the gas in the modulator means.
12. Apparatus according to claim 11 in which the modulation with the time varying electric field modulator means operates due to the Stark effect, or due to movement of polar gas molecules to align with the applied electric field.
13. Apparatus according to any one of the preceding claims in which the optical fibre light guidance system includes a reference path which is from the light source to the detector means for the light source and which bypasses the sensor means, the apparatus being such that light from the light source is split into two separate optical paths which are directed through the modulator means, in order to reference any attenuation changes due to the modulator means itself against those from the reference path obtained directly from the light source.
14. Apparatus according to any one of the preceding claims in which the sensor means is a sensor cell or a gas sensing region.
15. Apparatus according to any one of the preceding claims in which the modulator means is a modulator cell.
16. Apparatus according to any one of the preceding claims in which the light source is a hot gas which emits light.
17. Apparatus according to claim 16 in which the hot gas emits light due to relaxation of excited states via vibrational, rotational or electronic transitions.
18. Apparatus according to claim 16 or claim 17 in which the spectral distribution of the lines detected is monitored, using a frequency-swept optical filter in front of the detector means, in order to deduce the temperature of the hot gas.
19. Apparatus for monitoring a gas, substantially as herein described with reference to the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB898912446A GB8912446D0 (en) | 1989-05-31 | 1989-05-31 | Apparatus for monitoring a gas |
| GB898916777A GB8916777D0 (en) | 1989-07-21 | 1989-07-21 | Apparatus for monitoring a gas |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9011843D0 GB9011843D0 (en) | 1990-07-18 |
| GB2233087A true GB2233087A (en) | 1991-01-02 |
| GB2233087B GB2233087B (en) | 1993-09-29 |
Family
ID=26295420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9011843A Expired - Fee Related GB2233087B (en) | 1989-05-31 | 1990-05-25 | Apparatus for monitoring a gas |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2233087B (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2237630A (en) * | 1989-11-01 | 1991-05-08 | York Ltd | Apparatus for sensing a gas |
| WO1994009266A1 (en) * | 1992-10-13 | 1994-04-28 | Iris-Gmbh Infrared & Intelligent Sensors | Sensor arrangement and process for monitoring the conversion rate of an exhaust gas catalyst |
| EP1408325A2 (en) * | 2002-09-13 | 2004-04-14 | Delphi Technologies, Inc. | Method of measuring exhaust flow constituents |
| WO2010072578A1 (en) * | 2008-12-22 | 2010-07-01 | Universität Rostock | Method and device for measuring the concentration of substances in gaseous or fluid media through optical spectroscopy using broadband light sources |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4096388A (en) * | 1977-06-10 | 1978-06-20 | Hewlett-Packard Company | Measuring gaseous oxygen with U.V. absorption |
-
1990
- 1990-05-25 GB GB9011843A patent/GB2233087B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4096388A (en) * | 1977-06-10 | 1978-06-20 | Hewlett-Packard Company | Measuring gaseous oxygen with U.V. absorption |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2237630A (en) * | 1989-11-01 | 1991-05-08 | York Ltd | Apparatus for sensing a gas |
| WO1994009266A1 (en) * | 1992-10-13 | 1994-04-28 | Iris-Gmbh Infrared & Intelligent Sensors | Sensor arrangement and process for monitoring the conversion rate of an exhaust gas catalyst |
| EP1408325A2 (en) * | 2002-09-13 | 2004-04-14 | Delphi Technologies, Inc. | Method of measuring exhaust flow constituents |
| EP1408325A3 (en) * | 2002-09-13 | 2004-08-18 | Delphi Technologies, Inc. | Method of measuring exhaust flow constituents |
| WO2010072578A1 (en) * | 2008-12-22 | 2010-07-01 | Universität Rostock | Method and device for measuring the concentration of substances in gaseous or fluid media through optical spectroscopy using broadband light sources |
| GB2478254A (en) * | 2008-12-22 | 2011-08-31 | Univ Rostock | Method and device for measuring the concentration of substances in gaseous or fluid media through optical spectroscopy using broadband light sources |
| EP3009829A1 (en) * | 2008-12-22 | 2016-04-20 | Bluepoint Medical GmbH & Co. KG | Method and device for measuring the concentration of substances in gaseous or fluid media through optical spectroscopy using broadband light sources |
| US10408745B2 (en) | 2008-12-22 | 2019-09-10 | Bluepoint Medical Gmbh & Co. Kg. | Method and device for measuring the concentration of substances in gaseous or fluid media through optical spectroscopy using broadband light sources |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9011843D0 (en) | 1990-07-18 |
| GB2233087B (en) | 1993-09-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19970525 |