CN113324911A - Glass bottle applied to gas concentration detection and concentration detection method and system thereof - Google Patents
Glass bottle applied to gas concentration detection and concentration detection method and system thereof Download PDFInfo
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- 239000011521 glass Substances 0.000 title claims abstract description 150
- 238000001514 detection method Methods 0.000 title claims abstract description 42
- 230000003287 optical effect Effects 0.000 claims abstract description 83
- 238000010521 absorption reaction Methods 0.000 claims abstract description 66
- 238000000034 method Methods 0.000 claims abstract description 17
- 239000003814 drug Substances 0.000 claims abstract description 13
- 238000004364 calculation method Methods 0.000 claims description 12
- 239000007888 film coating Substances 0.000 claims description 2
- 238000009501 film coating Methods 0.000 claims description 2
- 239000011248 coating agent Substances 0.000 abstract description 8
- 238000000576 coating method Methods 0.000 abstract description 8
- 239000007789 gas Substances 0.000 description 50
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 9
- 229910052760 oxygen Inorganic materials 0.000 description 9
- 239000001301 oxygen Substances 0.000 description 9
- 238000010586 diagram Methods 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 3
- 230000009365 direct transmission Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
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- 238000011160 research Methods 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000000862 absorption spectrum Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 229930182555 Penicillin Natural products 0.000 description 1
- JGSARLDLIJGVTE-MBNYWOFBSA-N Penicillin G Chemical compound N([C@H]1[C@H]2SC([C@@H](N2C1=O)C(O)=O)(C)C)C(=O)CC1=CC=CC=C1 JGSARLDLIJGVTE-MBNYWOFBSA-N 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 238000012886 linear function Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229940049954 penicillin Drugs 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 229940126589 solid medicine Drugs 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 238000000041 tunable diode laser absorption spectroscopy Methods 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N21/03—Cuvette constructions
- G01N21/0303—Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment
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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
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Abstract
The invention discloses a glass bottle applied to gas concentration detection and a concentration detection method and a concentration detection system thereof, wherein gas to be detected is packaged in the glass bottle, and the glass bottle comprises an incident light channel opening, a cylindrical surface reflection channel and an emergent light channel opening; the incident light road junction is located the cylinder reflection channel upper border department, and cylinder reflection channel is located the glass bottle middle part, and emergent light road junction is located cylinder reflection channel lower border department, and is located the incident light road junction under. The method includes that laser is obliquely downwards emitted into a glass bottle from an incident light port through a laser, and is reflected for multiple times through a cylindrical surface reflection channel and then emitted from an emergent light port. The invention overcomes the problem of extremely short gas absorption optical path under the condition that laser directly transmits the glass medicine bottle through the total reflection coating on the outer wall of the glass bottle, greatly improves the absorption optical path of trace gas in the glass bottle, bypasses the diameter direction of the bottle body causing optical interference, and inhibits optical fluctuation interference to a greater extent, thereby greatly improving the detection precision of the gas concentration in the bottle.
Description
Technical Field
The invention belongs to the technical field of gas concentration detection, and particularly relates to a glass bottle for gas concentration detection, which is optimally designed by surrounding an internal reflection light path through a cylindrical surface of a packaged glass bottle, and a concentration detection method and a concentration detection system of the glass bottle.
Background
In order to realize the high-precision detection of the concentration of the trace gas in the packaged glass medicine bottle, the current general technology mostly adopts methods of shortening the distance of laser exposure in air outside the bottle, filling certain inert gas (such as nitrogen) in the whole detection background to isolate air, or continuously blowing certain gas outside a laser absorption line to reduce the contact of the laser outside the bottle to be detected with the air, and the like, and the requirements of the methods on the production environment are very strict.
The limited absorption optical path in the aseptic preparation packaging medicine bottle is a main obstacle for restricting the TDLAS technology to realize high-sensitivity detection of gas. At present, companies such as Lighthouse, BOSCH, and Brevetti in italy, which are in the leading edge of the technology, all manufacture a closed environment for detection, the optical path of laser actually absorbed in a glass bottle is the diameter length of the glass bottle, and the extremely short absorption length inevitably limits the precision and stability of laser detection. In the conventional method, in the open environment detection, because the process of the embodiment of detecting the concentration of the trace gas in the glass bottle is performed in an open environment, that is, in the total optical path from the laser emitted by the laser to the laser received by the detector, the optical path exposed in the open environment is much larger than the effective light absorption path in the bottle, so that errors often occur in the method for detecting the concentration of the trace gas in the bottle by directly transmitting the glass bottle in the open environment, the geometrical characteristics of the glass medicine bottle are researched, the technical bottleneck that the absorption optical path in the packaged medicine bottle is limited is solved, and the precision and the stability of the laser detection are improved.
Disclosure of Invention
The invention aims to solve the technical bottleneck that the absorption optical path in a packaged medicine bottle is limited, provides a brand-new method for optimally designing a cylindrical surface surrounding internal reflection optical path, effectively increases the absorption optical path of laser in a glass bottle, and further improves the detection precision and stability of the laser.
On one hand, the invention provides a glass bottle applied to gas concentration detection, wherein gas to be detected is packaged in the glass bottle, a laser reflection increasing film is plated on the outer wall of a bottle body of the glass bottle, and the glass bottle and the laser reflection increasing film form a cylindrical surface reflection channel;
the upper edge and the lower edge of the cylindrical surface reflection channel are respectively provided with an incident light channel opening and an emergent light channel opening, and the incident light channel opening and the emergent light channel opening are on the same vertical line;
the incident light passage opening is used for incidence of incident laser, and the laser emitted by the emergent light passage opening is collected and used for calculating the concentration of gas in the glass bottle.
The invention researches the geometric characteristics of the glass medicine bottle, focuses on the parallel transparent cylindrical part below the bottleneck of the glass medicine bottle, researches the geometric rule of multiple reflection and refraction of laser in the bottle by an incident angle, analyzes the optical condition of exciting multiple-beam interference in the bottle, utilizes the laser fluctuation characteristic by adopting a reverse thinking, establishes a mathematical model of key optical factors of a gas absorption optical path in the glass bottle on a laser incident point, an exit point, the internal reflection times, a surrounding mode and the like, develops the laser particle characteristic enhancement method research of gas absorption optical path optimization and multiple-beam interference inhibition in the bottle, greatly increases the absorption optical path of the laser in a packaged glass bottle, and achieves the effect of relatively weakening the influence of an open environment on the concentration precision of the gas in the glass bottle.
Optionally, the effective absorption optical path length of the laser in the cylindrical reflection channel is:
wherein, L is the effective absorption optical path length of the laser in the cylindrical reflection channel, M is the number of the effective absorption optical path sections of the laser in the glass bottle, and L1Is a section of effective absorption optical path in the projection length of X-Y plane, h1A drop height for an effective absorption optical path; the distance between the laser beam and the inner wall of the glass bottle after the laser beam passes through the gas in the bottle is used as an effective absorption optical path.
Alternatively, the calculation formula of the effective absorption optical path number M of the laser in the glass bottle is as follows:
wherein H is the height of the laser reflection increasing film coating on the outer glass bottle, m represents the refractive index of the laser from air to the bottle wall, r1Denotes the radius of the outer wall of the glass bottle, r2Denotes the radius of the inner wall of the glass bottle, alpha1Is the included angle between the projection of the laser incident angle on the X-Z plane and the X axis, and n is the side length number of the projection shape of the effective optical path track of the laser in the bottle on the X-Y plane and is a quasi-regular n-polygon.
Alternatively,projection length l of one section of effective absorption optical path in X-Y plane1And a reduced height h of an effective absorption optical path1The calculation formula of (a) is as follows:
wherein r is1Denotes the radius of the outer wall of the glass bottle, r2Denotes the radius of the inner wall of the glass bottle, alpha2Representing the angle of incidence, alpha, projected on the X-Y plane with respect to the X-axis1Is the included angle between the projection of the laser incident angle on the X-Z plane and the X axis, and n is the side length number of the projection shape of the effective optical path track of the laser in the bottle on the X-Y plane and is a quasi-regular n-polygon.
Alternatively, n and α2The equivalent relationship of (A) is as follows:
where m represents the refractive index of the laser light from air to the bottle wall.
Optionally, the vial is a glass vial.
In a second aspect, the present invention provides a method for detecting a gas concentration, comprising the steps of:
s1: the laser control module emits laser to penetrate into the glass bottle to be detected from a laser incident light port at a preset angle;
the glass bottle to be detected is the glass bottle, and incident laser is refracted and reflected downwards in the cylindrical reflection channel in a reciprocating spiral mode until the incident laser is emitted from the emergent light port;
s2: the laser detector receives the laser transmitted from the laser emergent light port, and obtains the gas concentration in the glass bottle according to the optical path of the laser in the glass bottle and the second harmonic current signal converted from the photoelectric signal received by the photoelectric detector.
Alternatively, the concentration formula of the gas is as follows:
in the formula i2fmaxThe second harmonic current signal is extracted by the laser detector which obtains laser and converts the laser into a current signal, and the current signal is subjected to quadrature demodulation with the high-frequency signal frequency doubling of the signal generator; l is the effective absorption optical path length of the laser in the cylindrical reflection channel, S is the second harmonic term coefficient, and N is the concentration of the gas.
Optionally, the gas is a trace gas, the trace gas being oxygen. In another aspect, the present invention provides a detection system based on the gas concentration detection method, including: the device comprises a laser control module, a laser source, a glass bottle, a laser detector, a signal generator and a data processor;
the laser control module is connected with the laser source and used for controlling the laser source to emit laser towards an incident light channel opening of the glass bottle;
laser is incident through an incident light channel opening on the glass bottle and is refracted and reflected downwards in the cylindrical reflection channel in a reciprocating spiral mode until the laser is emitted from the emergent light channel opening;
the laser detector is arranged at a position corresponding to an emergent light channel opening on the glass bottle and is used for collecting laser emitted from the emergent light channel opening and converting the laser into a current signal;
the signal generator is connected with the laser detector and is used for carrying out orthogonal demodulation on the current signal and the double frequency of the high-frequency signal to extract a second harmonic signal;
and the data processor is used for calculating the concentration of the gas to be detected in the glass bottle by utilizing the second harmonic signal and the effective absorption optical path length of the laser in the cylindrical reflection channel.
Advantageous effects
According to the glass bottle, the laser reflection increasing film is plated on the outer wall of the bottle body of the glass bottle, so that laser enters the glass bottle from the incident light opening at a preset oblique downward incident angle, the laser in the bottle is reflected for multiple times by the total reflection coating on the outer wall of the glass bottle, a longer absorption optical path of a certain gas in the bottle is obtained, and the problem that the gas absorption optical path is extremely short when the laser directly transmits through the glass bottle in the prior art is solved; in a further preferred scheme, the laser bypasses the diameter direction of the bottle body causing optical interference, and fluctuation interference is inhibited to the maximum extent, so that the detection precision and stability of the gas concentration in the bottle are greatly improved.
Drawings
FIG. 1 is a schematic diagram of the principles of the present invention;
FIGS. 2 (a) and (b) are schematic diagrams of a regular triangle-like structure of a bottle light trace projected on an X-Z, X-Y plane according to an embodiment of the present invention;
FIGS. 3 (a) and (b) are schematic sketches of a quasi-regular quadrilateral structure projected on an X-Z, X-Y plane of another light trace in the bottle according to an embodiment of the invention;
FIG. 4 is a graph of the second harmonic current detected by a detector after laser light has been transmitted directly through a glass bottle, wherein the oxygen concentration of a standard bottle is 5%;
FIG. 5 is a diagram of an embodiment of the present invention showing the second harmonic current detected by the detector after the laser passes through the cylindrical reflection channel of the present invention, wherein the optical trace in the bottle is a regular triangle-like shape, and the oxygen concentration of the standard bottle is 5% for two reflection periods;
FIG. 6 is another embodiment of the present invention, wherein the optical trace in the bottle is a quasi-regular quadrilateral, two reflection cycles, and the oxygen concentration in the standard bottle is 5%, after the laser passes through the cylindrical reflection channel of the present invention, the detector detects the second harmonic current.
Detailed Description
For the convenience of understanding of the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the conventional method, in the open environment detection, because the trace gas concentration detection process in the glass bottle 30 is performed in an open environment, the sum of the distance from the laser to the glass bottle entrance light path port 301 and the distance from the glass bottle exit light path port 303 to the laser detector is much larger than the diameter of the glass bottle to be detected, that is, in the total optical path from the laser emitted by the laser to the laser received by the detector, the optical path exposed in the open environment is much larger than the effective light absorption path in the bottle, which results in that if the method of directly transmitting the glass bottle to detect the trace gas concentration in the bottle in the open environment is adopted, errors often occur, that is, when the same glass medicine bottle is detected, the second harmonic obtained by the first and the second detection has a large amplitude fluctuation, as shown in fig. 4, the laser directly transmits the signal of the glass medicine bottle, and the demodulated current second harmonic amplitude jitter peak value is basically located between the intervals 5 and 6, the valley value is basically between 10 and 11, the range threshold of four second harmonic wave fluctuation in the graph occupies a larger ratio in the whole peak value, wherein the difference between the valley value 9 of the first second harmonic and the valley value 8 of the second harmonic is one third of the peak value of the second harmonic, the difference between the valley value 9 and the valley value 7 of the third second harmonic is larger, and the integral one results in that when the peak value is finally used for concentration inversion, the oxygen content in the same bottle at different times is calculated to be greatly changed, so that the detection precision is poor.
In view of the above, the glass bottle for gas concentration detection and the concentration detection method and system thereof provided by the present invention are used to obtain a longer absorption optical path of a certain gas in the bottle, so as to solve the above-mentioned problem of poor detection accuracy caused by too short absorption optical path. That is, it should be understood that the solution of the present invention can be applied to non-trace gases, and trace oxygen in this embodiment is often referred to as a condition where there may be air leakage in the "pharmaceutical packaged sterile preparation" which leads to the entry of oxygen (trace oxygen) into the glass bottle.
Referring to fig. 1, a perspective view of a cylindrical surround internal reflection mode provided in an embodiment of the present invention, and to fig. 2 and 3, a front view and a top view of two different cylindrical surround internal reflection embodiments are shown, in which the angle of the laser entering the glass bottle at the entrance of the incident light, the number of effective absorption optical path segments of the laser in the cylindrical reflection channel, and the projection shape on the X-Y plane are shown. Fig. 1 only shows the light track as being triangular-like in a glass vial and the number of effective absorption optical path segments as 12, it being understood that the invention is not so limited.
The embodiment of the invention provides a cylindrical surrounding internal reflection glass bottle 30, and the glass bottle 30 comprises an incident light channel port 301, a cylindrical reflection channel 302 and an emergent light channel port 303. The incident light channel opening 301 and the exit light channel opening 303 are respectively located at the upper edge and the lower edge of the cylindrical reflection channel 302, and the incident light channel opening 301 and the exit light channel opening 303 are located on the same vertical line. The aim is to have the laser emitter and the laser detector located on the same side. The cylindrical reflecting channel 302 is located in the middle of the glass bottle, and the specific position is determined according to various factors such as the shape and height of the glass bottle, the physical state and height of the medicine in the bottle and the like. Without loss of generality, the diameter of the bottle body of a 10ml penicillin bottle is 22mm, the height of the bottle body is 37mm, and the height of solid medicines at the bottom of the bottle is generally 10mm, so that the lower boundary of the cylindrical reflection channel is 15mm from the bottom of the bottle, the upper edge of the cylindrical reflection channel is 35mm from the bottom of the bottle, and the height of the cylindrical reflection channel is 20 mm.
The cylindrical reflection channel 302 can be realized by plating a layer of total reflection increasing film on the outer wall of the glass bottle, the absorption spectrum range of the cylindrical reflection increasing film is located outside the wavelength range of laser, and the scanning wavelength of the laser covers the absorption spectrum of the trace gas to be detected. The material of the reflection increasing film is not limited in the embodiment of the present invention.
Referring to fig. 1, laser enters the bottle 30 to be tested from the light emitting opening 301 in a downward direction at a predetermined angle, the laser entering the glass bottle is absorbed by trace gas in a frequency spectrum range, when the laser contacts the inner wall of the glass of the cylindrical reflection channel, the laser is refracted and enters the wall of the glass bottle, when the laser in the wall of the glass bottle contacts the outer wall coating of the cylindrical reflection channel, the laser is totally reflected, and finally the laser reflected in the wall of the glass bottle has a refraction value. Namely, the incident light channel opening 301 is a position where laser enters the glass bottle, and the laser can undergo refraction of air and glass wall and re-refraction of the glass bottle wall and the glass bottle when entering the glass bottle from the incident light channel opening; the cylindrical reflection channel 302 is used for expanding the effective absorption optical path of laser in the bottle, the laser in the reflection channel can generate refraction of the inner part of the glass bottle and the wall of the glass bottle, reflection of the wall of the glass bottle and the coating of the outer wall of the glass bottle and refraction of the wall of the glass bottle and the inner part of the glass bottle, the laser is repeatedly screwed downwards until the reflection frequency of the laser reaches the preset frequency, the laser is emitted from an emergent light port 303 below the coating, and therefore the purpose of increasing the effective absorption optical path of the laser in the glass bottle to be detected is achieved. The exit light port 303 is the specific location where the laser light in the bottle is transmitted out of the glass bottle, during which the laser light undergoes refraction from the inside of the glass bottle to the wall of the glass bottle and refraction from the wall of the glass bottle to the outside of the bottle.
Wherein the predetermined angle of incidence can be resolved as an angle α between the projection in the X-Y plane and the X-axis2And an angle alpha between the projection in the X-Z plane and the X axis1(ii) a By controlling the angle of incidence component alpha2The projection of the laser in the bottle on the X-Y plane can be formed into a regular n-polygon; while controlling the incident angle component alpha1The laser can be caused to make a predetermined integral number of turns around the bottle, and the number of effective optical path sections of the laser in the bottle is an integral multiple of n, so that the laser can be emitted from a predetermined laser emitting port 303. For example by controlling the angle alpha2So that the light track of the laser in the bottle is a quasi-regular quadrangle and then passes through the control angle alpha1So that the number of the surrounding cycles is 2, namely the number of the effective optical paths of the laser in the glass bottle is 8, and finally the laser is emitted from the laser emitting port. Therefore, the included angle alpha is adjusted according to the actual requirement and the application effect1And an included angle alpha2So that the application requirements can be met.
The laser passing through the incident light port 301 penetrates through the distance between the gas in the bottle and the inner wall of the glass bottle again from the inner wall of the glass bottle, namely a first section of effective absorption optical path; due to the cylindrical reflective channel 302 characteristics, there will also be a second segment, a third segment … …, where each segment has the same effective absorption optical path length.
Theoretical analysis:
in the conventional method, in the open environment detection, if the direct transmission method is adopted to detect the concentration of trace gas in a bottle, the light intensity signal I (t) detected by a photoelectric detector is as follows:
I(t)＝I0(t)·exp[-S1(T)N1L1P1g(v)]·exp[-S(T)NLPg(v)] (1)
in the embodiment, a cylindrical reflection channel is added in the detection glass bottle, and the emitted light intensity is I0The effective absorption optical path L of the laser in the glass bottle is greatly improved compared with the effective absorption optical path of direct transmission, so the weight of the absorption term exp [ -S (T) NLPg (v) of the laser in the bottle in the formula is increased, and the absorption exp [ -S (v) of the laser outside the bottle is relatively reduced1(T)N1L1P1g(v)]The weight of the term in the total light intensity absorption; when the effective absorption optical path of the laser in the bottle is large enough through the cylindrical reflection channel, the absorption term exp [ -S ] of the laser outside the bottle1(T)N1L1P1g(v)]Can ignore, and relativity greatly weakens the noise interference of the external environment, thereby improving the detection precision and stability of the concentration of trace gas in the glass medicine bottle.
That is, after the laser is reflected for multiple times in the detection bottle through the cylindrical reflection channel, the current signal i (t) of the laser coming out from the light exit port 303 after photoelectric conversion by the photoelectric detector has the calculation formula:
i(t)＝i0(t)exp[-S(T)NLPg(v)] (2)
wherein i0(T) is the injection current of the laser, S (T) is the absorption line intensity at temperature T, which is a function of temperature T only, N is the volume concentration of trace absorption gas in the bottle, L is the effective absorption optical path of the laser in the bottle, P is the static total pressure of the gas, g (v) is the linear function of the absorption lineAnd (4) counting.
Furthermore, laser is emitted from a preset emitting light port, the laser detector obtains the emitting laser, converts the emitting laser into a current signal, and then orthogonal demodulation is carried out on the current signal and the double frequency of a high-frequency signal of the signal generator, so that a second harmonic signal i of the current of the laser detector is extracted2f(t) the calculation formula is as follows:
i2f(t)＝i0(t)NLScos(2wt) (3)
wherein i0(t) is the laser injection current, S is the second harmonic term coefficient, w is the second harmonic current signal angular frequency, and t is time.
And finally, inverting the oxygen concentration information in the glass bottle according to the peak value of the second harmonic, wherein the calculation formula is as follows:
wherein i2fmaxThe second harmonic current signal peak.
Since the concentration inversion has been relatively good in the existing processing method, and is not the key point of the present application, it is not described herein again.
Specifically, the laser light in the bottle 30 to be detected has a first effective light absorption optical path projected on the X-Y plane as follows:
r1denotes the radius of the outer wall of the glass bottle, r2Denotes the radius of the inner wall of the glass bottle, alpha2Representing the angle of incidence projected on the X-Y plane with respect to the X-axis.
Further, by controlling the component α of the laser incidence angle2The shape of the polygon projected by the light trace in the bottle on the X-Y plane can be determined, and the side length and alpha of the quasi-regular n-polygon thereof2The equivalence relation is as follows:
wherein m represents the refractive index of the laser from air to the bottle wall, and n is the length of the side of the projection shape of the effective optical path track of the laser in the bottle in the X-Y plane. The regular-n-polygon-like shape is a regular triangle-like shape, a square-like shape, a regular pentagon-like shape or a polygon-like shape with other values.
Furthermore, the laser effectively absorbs the number of optical path sections in the cylindrical reflection channel according to the laser incidence angle and the Z-axis included angle, and the height h of the laser in each effective absorption optical path section is reduced1The calculation formula is as follows:
wherein alpha is1Is the included angle between the projection of the laser incidence angle on the X-Z plane and the X axis.
Referring to fig. 2, the projection of the light trace on the X-Y plane, the projection of the light trace AB on the horizontal axis of the bottle wall is approximately equal to the glass bottle wall thickness AC, under the premise that the distance the light trace descends in the vertical direction during the passage through the glass bottle wall is calculated as:
wherein beta is1The included angle between the projection of the refraction angle of the laser on the air-glass bottle wall on the X-Z plane and the X axis.
The calculation formula of the number M of the effective absorption optical path sections of the laser in the glass bottle is as follows:
wherein M is also an integral multiple of n, and H is the height of the cylindrical coating.
Further, the calculation formula of the effective absorption optical path length of the laser in the cylindrical reflection channel is as follows:
l, S, i in the above formula0(t)、i2fmaxIs in a linear relation with the concentration N of the gas; detecting the outer radius r of the bottle1Inner radius r2The refractive index m and the coating height H are determined.
The embodiments of the invention are explained in more detail below by way of example, the outer radius r of the vial currently in use111mm, inner radius r210mm, 20mm for the coating height, 1.51 for the refractive index of the glass, see fig. 2, and without loss of generality, the projected pattern of the preset light trace on the X-Y plane is in the shape of a regular triangle, and the included angle α between the laser incident from the incident light port and the X-Y plane can be derived by the above formula (6)228.74 °; at the same time, alpha is2The side length l of the regular triangle is obtained by the calculation of the formula (5)1The two regular triangle-like optical paths can be achieved by presetting the cylindrical reflection channel as 16.97mm, namely, the laser has 6 sections of effective absorption optical paths in the bottle, so that the included angle alpha between the incident angle and the Z axis can be obtained by the formula (9)1The effective absorption optical path drop height h of each segment in the bottle can be calculated according to the formula (7) after the effective absorption optical path drop height h is 11.76 DEG13.06mm, so that the total effective absorption optical path L of the laser in the bottle is 103.46mm under the control of the incident angle of the laser, and finally, the concentration of the trace gas in the bottle is obtained by processing the light intensity signal after the laser penetrates through the glass bottle.
Referring to fig. 5, for an embodiment of the present invention, a schematic diagram of a second harmonic of 4 consecutive cycles measured after the laser passes through the cylindrical reflection channel, where the reflected light trace of the laser in the bottle is a regular triangle-like shape and the operation cycle is two triangular cycles, it can be seen that the peak fluctuation of the second harmonic in the diagram is within 12, 13 thresholds, the valley fluctuation is within 14, 15 thresholds, the fluctuation variance of the amplitude of the second harmonic after passing through the regular triangle-like cylindrical surface is much smaller than the fluctuation variance of the amplitude of the second harmonic of the current after the laser directly transmits in fig. 4, and the amplitude of the second harmonic in fig. 5 has a larger gradient than that of the amplitude of the second harmonic in fig. 4, since the optical path of the laser in the open environment of the whole system is the same, but the effective absorption optical path of the laser in the bottle is increased by nearly 5 times compared with the direct transmission, the ratio of the threshold of the second harmonic at this time in the whole peak of the second harmonic is greatly, and the demodulated current second harmonic waveform is more regular, so that the method has relatively higher precision when the acquired current second harmonic peak value is used for inverting the concentration of trace gas in the bottle.
Referring to fig. 6, as another embodiment of the present invention, a schematic diagram of a second harmonic wave of 4 consecutive periods is obtained after laser passes through a cylindrical reflection channel, wherein a reflection track of the laser in a bottle is a quasi-orthodrome and an operation period is two quasi-tetragon periods, and it can be seen that an upper boundary of a second harmonic wave is within a threshold value of 16, 17 and a lower boundary of the second harmonic wave is within a threshold value of 18, 19.
Therefore, the invention optimizes the cylindrical surface surrounding internal reflection light path, constructs the laser particle characteristic optical amplifier in a narrow space, and relatively inhibits the amplitude fluctuation of the second harmonic, thereby effectively improving the precision of laser detection of trace gas concentration in the glass bottle and the stability of the system.
Based on the glass bottle with the optimized light path, the invention provides a gas concentration detection method using the glass bottle, which comprises the following steps:
s1: the laser control module emits laser to penetrate into the glass bottle to be detected from a laser incident light port at a preset angle, and the scanning wavelength of the laser covers an absorption spectral line of gas to be detected;
the glass bottle to be detected is the glass bottle, incident laser is refracted and reflected downwards in the cylindrical reflection channel in a reciprocating spiral mode until the incident laser is emitted from the emergent light port, and due to the structural characteristics of the glass bottle, an effective gas absorption optical path to be detected with the same length is added in the glass bottle to be detected after each reflection;
s2: the laser detector receives the laser transmitted from the laser emergent light port, and obtains the gas concentration in the glass bottle according to the optical path of the laser in the glass bottle and the second harmonic current signal converted from the photoelectric signal received by the photoelectric detector.
For the formula related to the optical path design, please refer to the corresponding description above, which is not repeated herein. Based on the gas concentration detection method, the invention provides a gas concentration detection system, which comprises: the device comprises a laser control module, a laser source, a glass bottle, a laser detector, a signal generator and a data processor;
the laser control module is connected with the laser source and used for controlling the laser source to emit laser towards an incident light channel opening of the glass bottle. The laser source is a laser, for example, the center wavelength of the laser is 760nm, the laser control module is used for controlling the temperature control and the current control of the normal operation of the laser, and the current control is a combined signal of a high-frequency sine wave and a low-frequency sawtooth wave carried by the laser driving device for the laser emission.
Laser is incident through an incident light channel opening on the glass bottle and is refracted and reflected downwards in the cylindrical reflection channel in a reciprocating spiral mode until the laser is emitted from the emergent light channel opening;
the laser detector is arranged at a position corresponding to an emergent light channel opening on the glass bottle and is used for collecting laser emitted from the emergent light channel opening and converting the laser into a current signal;
the signal generator is connected with the laser detector and is used for carrying out orthogonal demodulation on the current signal and the double frequency of the high-frequency signal to extract a second harmonic signal;
and the data processor is used for calculating the concentration of the gas to be detected in the glass bottle by utilizing the second harmonic signal and the effective absorption optical path length of the laser in the cylindrical reflection channel. The specific calculation formula can be referred to the aforementioned formula (4).
It should be emphasized that the examples described herein are illustrative and not restrictive, and thus the invention is not to be limited to the examples described herein, but rather to other embodiments that may be devised by those skilled in the art based on the teachings herein, and that various modifications, alterations, and substitutions are possible without departing from the spirit and scope of the present invention.
Claims (10)
1. The utility model provides a be applied to glass bottle of gas concentration detection which characterized in that: the glass bottle is internally packaged with gas to be detected, the outer wall of the bottle body of the glass bottle is plated with a layer of laser reflection increasing film, and the glass bottle and the laser reflection increasing film form a cylindrical surface reflection channel;
the upper edge and the lower edge of the cylindrical surface reflection channel are respectively provided with an incident light channel opening and an emergent light channel opening, and the incident light channel opening and the emergent light channel opening are on the same vertical line;
the incident light passage opening is used for incidence of incident laser, and the laser emitted by the emergent light passage opening is collected and used for calculating the concentration of gas in the glass bottle.
2. The glass bottle of claim 1, wherein: the effective absorption optical path length of the laser in the cylindrical reflection channel is as follows:
wherein, L is the effective absorption optical path length of the laser in the cylindrical reflection channel, M is the number of the effective absorption optical path sections of the laser in the glass bottle, and L1Is a section of effective absorption optical path in the projection length of X-Y plane, h1A drop height for an effective absorption optical path;
the distance between the laser beam and the inner wall of the glass bottle after the laser beam passes through the gas in the bottle is used as an effective absorption optical path.
3. The glass bottle of claim 2, wherein: the calculation formula of the effective absorption optical path number M of the laser in the glass bottle is as follows:
wherein H is the height of the laser reflection increasing film coating on the outer glass bottle, m represents the refractive index of the laser from air to the bottle wall, r1Denotes the radius of the outer wall of the glass bottle, r2Denotes the radius of the inner wall of the glass bottle, alpha1Is the included angle between the projection of the laser incident angle on the X-Z plane and the X axis, and n is the side length number of the projection shape of the effective optical path track of the laser in the bottle on the X-Y plane and is a quasi-regular n-polygon.
4. The glass bottle of claim 2, wherein: projection length l of one section of effective absorption optical path in X-Y plane1And a reduced height h of an effective absorption optical path1The calculation formula of (a) is as follows:
wherein alpha is2Representing the angle of incidence projected on the X-Y plane with respect to the X-axis.
5. The glass bottle of claim 4, wherein: n and alpha2The equivalent relationship of (A) is as follows:
where m represents the refractive index of the laser light from air to the bottle wall.
6. The glass bottle of claim 1, wherein: the glass bottle is a glass medicine bottle.
7. A gas concentration detection method is characterized in that: the method comprises the following steps:
s1: the laser control module emits laser to penetrate into the glass bottle to be detected from a laser incident light port at a preset angle;
the glass bottle to be detected is the glass bottle as claimed in any one of claims 1 to 6, and incident laser light is refracted and reflected downwards in a reciprocating spiral manner in the cylindrical reflection channel until the incident laser light is emitted from the light emitting port;
s2: the laser detector receives the laser transmitted from the laser emergent light port, and obtains the gas concentration in the glass bottle according to the optical path of the laser in the glass bottle and the second harmonic current signal converted from the photoelectric signal received by the photoelectric detector.
8. The method of claim 7, wherein: the concentration formula of the gas is as follows:
in the formula i2fmaxThe second harmonic current signal is extracted by the laser detector after acquiring laser and converting the laser into a current signal and performing orthogonal demodulation on the current signal and a high-frequency signal generated by the demodulation board; l is the effective absorption optical path length of the laser in the cylindrical reflection channel, S is the second harmonic term coefficient, and N is the concentration of the gas.
9. The method of claim 7, wherein: no interference of other elements exists near the gas absorption line.
10. A detection system based on the method of claim 7, wherein: the method comprises the following steps: the device comprises a laser control module, a laser source, a glass bottle, a laser detector, a signal generator and a data processor;
the laser control module is connected with the laser source and used for controlling the laser source to emit laser towards an incident light channel opening of the glass bottle;
laser is incident through an incident light channel opening on the glass bottle and is refracted and reflected downwards in the cylindrical reflection channel in a reciprocating spiral mode until the laser is emitted from the emergent light channel opening;
the laser detector is arranged at a position corresponding to an emergent light channel opening on the glass bottle and is used for collecting laser emitted from the emergent light channel opening and converting the laser into a current signal;
the laser detector is connected with the demodulation board and used for carrying out orthogonal demodulation on the current signal and the double frequency of the high-frequency signal to extract a second harmonic signal;
and the data processor is used for calculating the concentration of the gas to be detected in the glass bottle by utilizing the second harmonic signal and the effective absorption optical path length of the laser in the cylindrical reflection channel.
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