CN117330534B - High-precision infrared spectroscopic oil meter - Google Patents
High-precision infrared spectroscopic oil meter Download PDFInfo
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- CN117330534B CN117330534B CN202311616410.4A CN202311616410A CN117330534B CN 117330534 B CN117330534 B CN 117330534B CN 202311616410 A CN202311616410 A CN 202311616410A CN 117330534 B CN117330534 B CN 117330534B
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- reflecting mirror
- slit
- concave reflecting
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- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 67
- 239000010937 tungsten Substances 0.000 claims abstract description 67
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 66
- 230000003287 optical effect Effects 0.000 claims description 12
- 238000003384 imaging method Methods 0.000 claims description 6
- 238000001514 detection method Methods 0.000 abstract description 16
- 230000000694 effects Effects 0.000 abstract description 5
- 238000001228 spectrum Methods 0.000 description 11
- 239000003921 oil Substances 0.000 description 10
- 235000019198 oils Nutrition 0.000 description 10
- 238000000034 method Methods 0.000 description 7
- 239000003208 petroleum Substances 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 239000010775 animal oil Substances 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 235000015112 vegetable and seed oil Nutrition 0.000 description 3
- 239000008158 vegetable oil Substances 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000001678 irradiating effect Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000004566 IR spectroscopy Methods 0.000 description 1
- CYTYCFOTNPOANT-UHFFFAOYSA-N Perchloroethylene Chemical group ClC(Cl)=C(Cl)Cl CYTYCFOTNPOANT-UHFFFAOYSA-N 0.000 description 1
- 238000002835 absorbance Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- 229910052919 magnesium silicate Inorganic materials 0.000 description 1
- 235000019792 magnesium silicate Nutrition 0.000 description 1
- 239000000391 magnesium silicate Substances 0.000 description 1
- 238000011002 quantification Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229950011008 tetrachloroethylene Drugs 0.000 description 1
- 230000009466 transformation Effects 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
- G01N21/25—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
- G01N21/3577—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing liquids, e.g. polluted water
-
- 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
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
-
- 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
- G01N2201/06—Illumination; Optics
- G01N2201/061—Sources
Abstract
The invention discloses a high-precision infrared spectroscopic oil meter, which belongs to the technical field of detection equipment and comprises a light source chamber, a spectroscopic chamber and a sample chamber which are sequentially arranged, wherein an incident slit is arranged at the joint of the light source chamber and the spectroscopic chamber, the incident slit is positioned in a first shading cylinder, an emergent slit is arranged at the joint of the spectroscopic chamber and the sample chamber, and the emergent slit is positioned in a second shading cylinder; the light source chamber is internally provided with a tungsten lamp and a first plano-concave reflecting mirror, the light splitting chamber is internally provided with a second plano-concave reflecting mirror, a grating and a third plano-concave reflecting mirror, the second plano-concave reflecting mirror is arranged on one side of the light splitting chamber away from the light source chamber, the grating is arranged between the incident slit and the emergent slit, and the third plano-concave reflecting mirror and the emergent slit are arranged on two sides of a connecting line between the incident slit and the second plano-concave reflecting mirror. The oil detector provided by the invention can improve the detection light intensity and the light purity by optimizing the light path and the light path fittings, and finally achieves the effect of improving the signal intensity, thereby realizing the accurate detection of the low-concentration sample.
Description
Technical Field
The invention relates to an oil meter, in particular to a high-precision infrared spectroscopic oil meter, and belongs to the technical field of detection equipment.
Background
The infrared spectroscope is to extract with tetrachloroethylene to measure total extract (petroleum and animal and vegetable oil), adsorb the extract with magnesium silicate, remove polar substances such as animal and vegetable oil, and measure petroleum. The total extract and petroleum content are 2930 and cm respectively -1 (stretching vibration of C-H bond in CH2 group), 2960 cm -1 (stretching vibration of C-H bond in CH3 group) and 3030cm -1 Absorbance a at the (stretching vibration of C-H bond in aromatic ring) band 2930 ，A 2960 ，A 3030 And (5) performing calculation. The content of animal and vegetable oil is calculated according to the difference between the total extract and petroleum content. The infrared spectroscopic oil meter is realized byThe full spectrum light is split to separate 2930 and 2930 cm -1 ，2960 cm -1 And 3030cm -1 The light of these 3 points was irradiated to the sample, and the actual concentration was calculated from the values absorbed by the sample.
The conventional implementation method at present is that a light source generates full spectrum, the full spectrum is reflected for multiple times by a reflecting mirror, parallel light is obtained by grating light splitting and enters a cuvette, and a sample to be detected is arranged in A 2930 ，A 2960 ，A 3030 The 3 points have the characteristic of absorbing infrared spectrum, and finally the concentration of the sample to be detected is calculated through the difference value detected by the photocell.
Most of infrared spectroscopic oil meters do not fully consider the problems of ensuring light intensity, light purity, heating and the like when the whole light path design is carried out, so that the light entering into a cuvette is very weak or the signal value change which is not detected enough in purity is too small, and the oil meters on the market are difficult to accurately detect when the detection of low-concentration samples is carried out.
In summary, the prior art obviously has inconvenience and defects in practical use, so it is necessary to provide a high-precision infrared spectroscopic oil meter to solve the bottleneck of the prior art.
Disclosure of Invention
Aiming at the defects in the background technology, the invention provides the high-precision infrared spectroscopic oil meter which can improve the detection light intensity and the light purity under the condition of optimizing the light path and the light path fittings, finally achieve the effect of improving the signal intensity and realize the accurate detection of the low-concentration sample.
In order to solve the technical problems, the invention adopts the following technical scheme:
the high-precision infrared spectroscopic oil meter comprises a light source chamber, a spectroscopic chamber and a sample chamber which are sequentially arranged, wherein an incident slit is arranged at the joint of the light source chamber and the spectroscopic chamber, the incident slit is positioned in a first shading cylinder, an emergent slit is arranged at the joint of the spectroscopic chamber and the sample chamber, and the emergent slit is positioned in a second shading cylinder;
a tungsten lamp and a first plano-concave reflecting mirror are arranged in the light source chamber, the tungsten lamp is arranged close to the entrance slit, and the tungsten lamp is positioned at the side part of a connecting line between the entrance slit and the first plano-concave reflecting mirror;
the light splitting chamber is of a square structure, a second plano-concave reflecting mirror, a grating and a third plano-concave reflecting mirror are arranged in the light splitting chamber, the second plano-concave reflecting mirror is arranged on one side of the light splitting chamber, which is far away from the light source chamber, the grating is arranged between the incident slit and the emergent slit, and the third plano-concave reflecting mirror and the emergent slit are arranged on two sides of a connecting line between the incident slit and the second plano-concave reflecting mirror;
the first plano-concave reflector collects and reflects light irradiated by the tungsten lamp to the incident slit, the light transmitted through the incident slit enters the light splitting chamber to irradiate on the second plano-concave reflector, the second plano-concave reflector reflects the light to the grating to split light, the light with different wavelengths is separated and irradiated on the third plano-concave reflector through rotation of the grating to be focused again, and the focused light enters the sample chamber through the emergent slit.
Further, a collimating objective, a cuvette, an imaging objective, an optical filter and a photocell sensor are sequentially arranged behind the emergent slit, and the center of the photocell sensor and the center of the emergent slit are on the same straight line.
Further, the power of the tungsten lamp is more than or equal to 20W; the cross section area of the filament of the tungsten lamp is in a strip rectangular shape; the tungsten lamp filament is kept in a vertical direction.
Further, the rectangular hole shape and the length-width ratio of the incident slit and the emergent slit are the same as the cross section of the filament of the tungsten lamp; the width of the incident slit is less than or equal to 0.5mm.
Further, the tungsten lamp is located at an intersection of the outer diameter of the tungsten lamp bulb and one focal length of the first plano-concave reflector outward of the entrance slit.
Further, an air inlet fan and an air outlet fan which are arranged side by side are arranged on the side wall, far away from the light splitting chamber, of the light source chamber, an air channel is formed, and air flow is formed in the light source chamber.
Further, the first shading cylinder comprises a large-diameter cylinder and a small-diameter cylinder which are arranged in a collinear manner, the lengths and the diameters of the large-diameter cylinder and the small-diameter cylinder are different, the small-diameter cylinder is positioned in the light source chamber, the large-diameter cylinder is positioned in the light splitting chamber, and the incident slit is positioned in the end part of the small-diameter cylinder, which is close to the large-diameter cylinder.
Further, the small diameter cylinder diameter D of the first shading cylinder, and the distance L from the tangent point A of the connecting line of the incident slit and the outer diameter of the tungsten lamp to the vertical plane where the incident slit is positioned; the distance L1 between the first plano-concave reflecting mirror and the entrance slit, the diameter D1 of the first plano-concave reflecting mirror, the proportional equation is D1/L1=D/L, and the optimal size of the diameter D is calculated as D=LxD1/L1.
Further, the diameter of the large diameter cylinder in the light splitting chamber is D, the length of the large diameter cylinder is L, the distance from the edge of the third plano-concave reflecting mirror to the vertical plane where the incident slit is located is L1, the transverse distance D1 between the third plano-concave reflecting mirror and the incident slit is D1/L1=D/L, and the optimal size of the diameter D is calculated to be D=L×D1/L1.
Further, the distance between the incident slit and the second plano-concave reflecting mirror is equal to the focal length of the second plano-concave reflecting mirror, the second plano-concave reflecting mirror is inclined at a certain angle, the second plano-concave reflecting mirror emits light into the grating in parallel, the grating rotates along the center of the grating, and diffracted light is directed to the third plano-concave reflecting mirror through rotation of the grating.
After the technical scheme is adopted, compared with the prior art, the invention has the following advantages:
according to the invention, the high-power tungsten lamp is used as a light source to emit full spectrum light, so that the problem of the occupation ratio of the infrared part of the light source is well solved, and the light intensity entering a cuvette at the rear can be improved; the cross section area of the tungsten lamp filament is in a strip rectangular shape, so that the phenomenon of light overlapping of adjacent spectrums after light splitting is reduced, the tungsten lamp filament keeps in a vertical direction, light can penetrate through an incident slit and an emergent slit to the greatest extent, and the light loss is reduced;
according to the invention, the incident slit is arranged in the shading cylinder, so that the shading cylinder can just shade interference light directly emitted by the tungsten lamp and can receive light spots reflected by the first plano-concave reflecting mirror to the maximum extent, and thus, a light path can only enter the light splitting chamber through the tungsten lamp, the first plano-concave reflecting mirror and the incident slit in a unique path, the uniqueness of incident light is ensured, the purity of light is improved, and the sensitivity of detecting a low-concentration sample is improved by phase change;
the grating rotates along the center of the grating, so that light irradiates back and forth for 4 times in the same square space, and the original light with the optical path length of 4 times is changed into a square light splitting chamber with the optical path length of one time as the side length through the position design of the second plano-concave reflector, the grating, the third plano-concave reflector and the emergent slit, thereby greatly saving the space of an instrument, ensuring that the instrument is more compact and the space utilization rate is higher;
the cuvette adopts a post-positioned method, only the separated needed wavelength spectrum irradiates the sample, and all light paths are designed in the light source chamber, the light splitting chamber and the sample chamber, so that the cuvette can play a role of a good airtight space, completely separate the environment of the whole cuvette, is not influenced by ambient light, greatly reduces the background value of a detection signal, can well improve the sensitivity of the instrument, and realizes high-precision detection.
The invention will now be described in detail with reference to the drawings and examples.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention;
FIG. 2 is a schematic diagram of the distribution of the components within the light source chamber;
FIG. 3 is a schematic view of the structure of the first shade tube;
fig. 4 is a schematic diagram of the distribution of a third plano-concave mirror in a spectroscopic chamber.
In the figure, a 1-tungsten lamp, a 2-first plano-concave reflecting mirror, a 3-air inlet fan, a 4-air outlet fan, a 5-incident slit, a 6-first shading cylinder, a 7-second plano-concave reflecting mirror, an 8-grating, a 9-third plano-concave reflecting mirror, a 10-emergent slit, a 11-second shading cylinder, a 12-collimating objective lens, a 13-cuvette, a 14-imaging objective lens, a 15-optical filter, a 16-photocell sensor, a 17-light source chamber, a 18-light splitting chamber and a 19-sample chamber.
Detailed Description
For a clearer understanding of technical features, objects, and effects of the present invention, a specific embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in fig. 1-4 together, the invention provides a high-precision infrared spectroscopic oil meter, which comprises a light source chamber 17, a spectroscopic chamber 18 and a sample chamber 19 which are sequentially arranged.
An entrance slit 5 is arranged at the joint of the light source chamber 17 and the light splitting chamber 18, and the entrance slit 5 is positioned in the first shading cylinder 6.
An exit slit 10 is arranged at the joint of the light splitting chamber 18 and the sample chamber 19, and the exit slit 10 is positioned in the second shading barrel 11.
The tungsten lamp 1 and the first plano-concave reflecting mirror 2 are installed in the light source chamber 17, and the first plano-concave reflecting mirror 2 collects light emitted from the tungsten lamp 1 and spherically reflects the light to collect the light into the rear entrance slit 5.
The light splitting chamber 18 is of a square structure, and the second plano-concave reflecting mirror 7, the grating 8 and the third plano-concave reflecting mirror 9 are arranged in the light splitting chamber 18. The grating 8 is located between the entrance slit 5 and the exit slit 10, the second plano-concave reflecting mirror 7 is located at one side of the light splitting chamber 18 away from the light source chamber 17, and the third plano-concave reflecting mirror 9 and the exit slit 10 are located at two sides of the connecting line between the entrance slit 5 and the second plano-concave reflecting mirror 7.
The light enters the light splitting chamber 18 from the entrance slit 5 and irradiates the second plano-concave reflecting mirror 7, the second plano-concave reflecting mirror 7 gathers the scattered light into parallel light and directs the parallel light to the grating 8, the grating 8 splits the light and directs the split parallel light to the third plano-concave reflecting mirror 9 again, the third plano-concave reflecting mirror 9 condenses the parallel light, and the light is focused on the exit slit 10 to finish the light splitting, and waits for entering the cuvette 13.
The power of the tungsten lamp 1 is more than or equal to 20W, and the high-power tungsten lamp 1 is used as a light source to emit full spectrum light. Since infrared spectroscopy needs to separate 3030cm -1 ，2960 cm -1 ，2930 cm -1 The light source must be able to contain these infrared portions, and a common incandescent or energy-saving lamp will be used for its primary purpose, so that there is substantially no mid-far infrared portion or very low, which will result in a very low spectral power required for future splitting, and the use of the tungsten lamp 1 can contain as much of the spectrum of the infrared portion as possible, which well solves the problem of the infrared portion duty cycle of the light source.
The power of the light-emitting source directly determines the energy value in the whole light stroke, and the power increase can improve the light intensity entering the cuvette 13 at the back, so that the light intensity value reduction caused by the loss on the light path is reduced as much as possible when the light path at the back is used for light splitting or light gathering, and the reduction of a large amount of light intensity values caused by the loss on the light path in the process of relatively long-distance propagation can be avoided.
According to the invention, the cross section area of the filament of the tungsten lamp 1 is in a strip rectangular shape, so that after light is split by the grating 8 in the future, the light overlapping phenomenon of the split adjacent spectrums is not serious because the original light spot is thinner, and the light can be split more thinly. The tungsten lamp 1 is installed to ensure that the filament of the tungsten lamp keeps vertical direction, so that the tungsten lamp can be matched with the shape of light transmitted by the slit when the light is focused on the entrance slit 5 and focused on the exit slit 10 after the light is split in the future, and the light can be transmitted through the entrance slit 5 and the exit slit 10 to the maximum extent, so that the light loss is reduced. The rectangular hole shape and the aspect ratio of the entrance slit 5 and the exit slit 10 are the same as those of the filament of the tungsten lamp 1, so that more light can be transmitted through the entrance slit 5 and the exit slit 10 to the maximum extent. In the prior art, the chopping method is carried out by a chopper, but the chopping is carried out by a method of controlling the switch of the tungsten lamp 1 by an electric control system, and the tungsten lamp 1 is turned on or off by the electric control system, so that a physical chopping part can be removed, the volume of the part is reduced, and the whole light path is optimized.
The side wall of the light source chamber 17 far away from the light splitting chamber 18 is provided with the air inlet fan 3 and the air outlet fan 4 which are arranged side by side, and an air duct is formed, so that air flow is formed in the light source chamber 17, the problem that the tungsten lamp 1 generates heat very seriously due to relatively large power is avoided, the temperature of the whole machine can be effectively reduced, and temperature drift is avoided.
The tungsten lamp 1 in the present invention is disposed near the entrance slit 5, and the tungsten lamp 1 is located at the side of the line between the entrance slit 5 and the first plano-concave reflecting mirror 2. The tungsten lamp 1 is positioned at the intersection point of the outer diameter of the bulb of the tungsten lamp 1 and the focal length of the first plano-concave reflecting mirror 2, which is arranged outwards of the entrance slit 5, and the arrangement has the advantage that the singleness of the incident light is ensured, and the entrance slit 5 is ensured to only receive the focused light reflected by the first plano-concave reflecting mirror 2.
If the tungsten lamp 1 is provided with the first plano-concave reflecting mirror 2 and the entrance slit 5 on the same straight line as in the prior art, the light entering the entrance slit 5 is affected, which corresponds to the superposition of the light source light directly irradiated by the entrance slit 5 and the focused light reflected by the first plano-concave reflecting mirror 2, so that different paths are formed by the two light during the subsequent light treatment and the light splitting, and the light treatment is not easy.
According to the invention, the tungsten lamp 1 deviates from the connecting line between the entrance slit 5 and the first plano-concave reflecting mirror 2 to give an angle, so that the entrance slit 5 can only receive the focused light reflected by the first plano-concave reflecting mirror 2, the tungsten lamp 1 cannot directly irradiate into the entrance slit 5 through light path propagation (the interference light of the part can be completely blocked through the cooperation of the first shading cylinder 6), and therefore, by changing the position of the tungsten lamp 1, the light path can only enter the light splitting chamber 18 through the unique path tungsten lamp 1-the first plano-concave reflecting mirror 2-the entrance slit 5, and the uniformity of the incident light is ensured.
Meanwhile, an included angle is formed between the tungsten lamp 1 and the first plano-concave reflecting mirror 2 and between the incident slit 5, so that a theoretical point light source cannot be used for irradiating the reflecting mirror, the reflected light travels to reduce an inverted real image, and light spots irradiated on the incident slit 5 can be changed into crescent shapes due to the existence of the included angle in actual design, so that light entering the incident slit 5 is different from a long rectangular shape of a light source, and the shape and signal value of the light spots at the back are affected. The design for this problem is to solve the problem by adjusting the angle of this included angle, adjusting the shape and size of the crescent and adding a shading barrel, so that the light entering the entrance slit 5 presents a uniform, rectangular narrow light spot, specifically designed as follows:
the distance between the tungsten lamp 1 and the entrance slit 5 is designed to enable the tungsten lamp 1 to be close to the entrance slit 5 and be a vertical distance from the entrance slit 5 to the outer diameter of a bulb of the tungsten lamp 1, so that the size of a crescent light spot formed can be reduced to the greatest extent, the shape of the crescent light spot is close to a rectangle, and a larger design space is provided for rectangular cutting afterwards. The distance between the tungsten lamp 1 and the first plano-concave reflecting mirror 2 is slightly larger than the focal length of the first plano-concave reflecting mirror 2, and the distance between the first plano-concave reflecting mirror 2 and the entrance slit 5 is slightly smaller than the focal length of the first plano-concave reflecting mirror, so that the first plano-concave reflecting mirror 2 can collect more light, an enlarged and inverted real image can be displayed at the entrance slit 5, and the light can be better focused at the entrance slit 5 and then enter the following treatment.
The final tungsten lamp 1 is positioned at the intersection of the outer diameter of the tungsten lamp 1 and the focal length of the first plano-concave reflector 2, one time, outward of the entrance slit 5.
Because the tungsten lamp 1 is very close to the entrance slit 5, a part of light emitted by the tungsten lamp 1 can directly enter the entrance slit 5 and interfere the treatment of the light of the rear light splitting chamber 18, the first shading cylinder 6 is additionally arranged at the entrance slit 5, the first shading cylinder 6 can effectively prevent the light emitted by the tungsten lamp 1 from directly entering the light splitting chamber 18 through the entrance slit 5 and blocking the light from being emitted into the entrance slit 5, so that the tungsten lamp 1 is close to the entrance slit 5 to make a reflected crescent light spot not obvious, and interference light directly emitted by the tungsten lamp 1 can be blocked, the purity of the light is improved, and the sensitivity of detecting a low-concentration sample is also improved.
The first shading cylinder 6 comprises a large-diameter cylinder and a small-diameter cylinder which are arranged in a collinear way, the lengths and the diameters of the large-diameter cylinder and the small-diameter cylinder are different, the small-diameter cylinder is positioned in the light source chamber 17, the large-diameter cylinder is positioned in the light splitting chamber 18, and the incident slit 5 is positioned in the end part of the small-diameter cylinder, which is close to the large-diameter cylinder.
The distance L from the tangent point A of the connecting line of the incident slit 5 and the outer diameter of the tungsten lamp 1 to the vertical plane where the incident slit 5 is located is the optimal position which can be close to the connecting line of the first plano-concave reflector 2 and the incident slit 5 and can not block light when the distance L is the small diameter cylinder diameter D of the first shading cylinder 6. The distance L1 between the first plano-concave reflecting mirror 2 and the entrance slit 5, the diameter D1 of the first plano-concave reflecting mirror, and L are in a proportional relationship, the proportional equation is D1/l1=d/L, and the optimal dimension of the diameter D is calculated as d=l×d1/L1. The small-diameter cylinder with the determined size can not only just shade the light directly emitted by the tungsten lamp 1, but also receive the light spot reflected by the first plano-concave reflecting mirror 2 to the maximum extent.
When light is focused on the entrance slit 5, the width of the entrance slit 5 needs to be designed as narrow as possible, and the range is controlled to be less than or equal to 0.5mm. The incident slit 5 is a rectangular hole cut in the first shading barrel 6, the height of the incident slit 5 is designed according to the equal proportion of the length and the width of the filament of the tungsten lamp 1, the width is narrowed as much as possible on the basis of the equal proportion design, and the practical slotting width is preferably less than or equal to 0.5mm. Narrowing of the entrance slit 5 results in a decrease in the intensity of light passing therethrough, but allows higher purity of light split out from the subsequent spectroscopic cell, so that when 3 detection of the wavelength bands to be absorbed are performed, the stray light is less due to the purer light, and although the signal value is somewhat lower, the peak height of the single point response value at each point is steeper, and in particular, the quantification is easier when detecting a low concentration. The light reflected by the first plano-concave reflecting mirror 2 has stray light except the collected light, the incident slit 5 is used for blocking the stray light, only the light with the slit width of 0.5mm after the light is collected enters the light splitting chamber 18, the stray light is well filtered, and the purity of the light is improved. Meanwhile, crescent light spots generated by the first plano-concave reflecting mirror 2 and the tungsten lamp 1 due to the angle problem can be cut, a narrow rectangle is cut inside the light spots, irregular parts are removed, and light sources in the subsequent light treatment process are tidier, so that the light spots are more regular.
Although light is focused on the entrance slit 5 and enters the spectroscopic chamber 18 through the large-diameter tube, in theory, the small-diameter tube of the light source chamber 17 can shield all stray light, and only the rectangular light spot cut out by the entrance slit 5 enters the spectroscopic chamber 18, in practice, light still enters the spectroscopic chamber 18 through reflection at the inner side of the entrance slit 5, and light which is extremely weak is influenced to finally enter the cuvette 13, so that the final absorption detection is influenced, the detection precision is reduced, and the detection accuracy is also influenced, so that the large-diameter tube is arranged behind the entrance slit 5, the stray light is shielded through the large-diameter tube, the light is blocked from being irradiated onto other light path fittings other than the second concave reflecting mirror 7 of the spectroscopic chamber 18, reflection cannot be formed again by directly irradiating the light onto other fittings, and the light source of the spectroscopic chamber 18 can be completely blocked from the stray light of the front stage, and the light source of the spectroscopic chamber 18 is extremely pure.
The length of the large diameter cylinder in the light splitting chamber 18 is L, the diameter of the large diameter cylinder is D, the distance from the edge of the third plano-concave reflecting mirror 9 to the vertical plane where the entrance slit 5 is located is L1, the transverse distance D1 between the third plano-concave reflecting mirror 9 and the entrance slit 5 is D1/l1=d/L, and the optimal size of the diameter D is calculated as d=l×d1/L1.
The distance between the entrance slit 5 and the second concave mirror 7 is equal to the focal length of the second concave mirror 7, so that the light reflected from the second concave mirror 7 is parallel light, and the second concave mirror 7 is inclined at a certain angle to inject the light into the grating 8 in parallel.
The distance between the entrance slit 5 and the second plano-concave mirror 7 is designed as b, half of the side length of the grating 8 is set as a, and the grating 8 forms an equilateral triangle with the second plano-concave mirror 7 between the entrance slit 5 and the exit slit 10, so that the included angle at the entrance slit 5 is 60 degrees, the side length of the grating 8 is 40mm assuming b=150 mm, the minimum included angle between the side length of the grating 8 near the entrance slit 5 and the entrance slit 5 at the second plano-concave mirror 7 is 7.053 degrees, and the maximum included angle can be 52.947 degrees by using the same calculation method. Therefore, by designing the placement angle of the second plano-concave reflecting mirror 7, light is reflected again to the position of the grating 8, a large-section light path extending space can be saved, the space is reused, and the effect of optimizing the light path is achieved.
The grating 8 can rotate along the center of the grating, diffracted light is directed to the third plano-concave reflecting mirror 9 through the rotation of the grating, the third plano-concave reflecting mirror 9 is positioned on the other side of a connecting line of the incident slit 5 and the second plano-concave reflecting mirror 7, and the position of the emergent slit 10 is designed on the side of the grating 8 of the incident slit 5 and the second plano-concave reflecting mirror 7, so that the light can be irradiated back and forth for 4 times in the same square space, and the original 4 times of light with the optical path length is changed into a square light splitting chamber 18 with the single-time optical path length as a side length through the position design of the second plano-concave reflecting mirror 7, the grating 8, the third plano-concave reflecting mirror 9 and the emergent slit 10, so that the instrument space is greatly saved, the instrument is more compact, and the space utilization rate is higher.
Since the light is irradiated 4 times to the spectroscopic chamber 18 and is reflected 3 times, particularly, the light is diffracted after passing through the grating 8, light of other wavelengths after being partially split in the spectroscopic chamber 18 propagates along other optical paths, and the light enters the emission slit 10 and is finally absorbed by the sample in the cuvette 13, so that the emission slit 10 is disposed in the second light shielding tube 11 and can be blocked by other stray light, and the second light shielding tube 11 plays a role of allowing only the light reflected by the third plano-concave reflecting mirror 9 to enter the emission slit 10 and blocking all the light reflected in other directions.
The length of the second light shielding barrel 11 is the perpendicular distance L between the intersection point of the outgoing slit and the outer side of the second plano-concave reflecting mirror and the intersection point of the inner side of the grating and the connecting line of the third plano-concave reflecting mirror and the outgoing slit, the distance between the third plano-concave reflecting mirror and the outgoing slit is L1, and the width of the third plano-concave reflecting mirror is D1, then the diameter of the second light shielding barrel 11 is d=l×d1/L1.
The rear of the exit slit 10 is sequentially provided with a collimating objective 12, a cuvette 13, an imaging objective 14, an optical filter 15 and a photocell sensor 16, wherein the center of the photocell sensor 16 is correspondingly arranged on the center of the exit slit 10, is ensured to be on a straight line and is arranged on a light plane.
The user puts the cuvette 13 filled with liquid into the sample chamber 19, the light from the exit slit 10 can be regarded as a point light source, the collimator lens 12 converts the point light source into parallel light to enter the cuvette 13, then the parallel light passing through the cuvette is focused into the point light source by the imaging lens 14, and the stray light is filtered out again by the optical filter 15 and finally enters the photocell sensor 16.
Through the design of the whole light path, all the light paths are designed in the light source chamber 17, the light splitting chamber 18 and the sample chamber 19, so that the effect of a good airtight space can be achieved, the environment where the whole machine is located is completely separated, the influence of ambient light is avoided, the background value of a detection signal is greatly reduced, the sensitivity of the instrument is improved well, and high-precision detection is realized.
The specific working principle of the invention is as follows:
the first plano-concave reflecting mirror 2 serves as a spherical reflecting mirror to collect and reflect light irradiated to the incident slit 5, the light is focused on the incident slit 5, the light enters the light splitting chamber 18 to irradiate the second plano-concave reflecting mirror 7 after passing through the incident slit 5, the second plano-concave reflecting mirror 7 reflects parallel light to irradiate the grating 8, the grating 8 splits the original synthesized spectrum, the light with different wavelengths is separated and irradiated on the third plano-concave reflecting mirror 9 through rotation of the grating 8 to be focused again, the focused light irradiates on the emergent slit 10 to enter the sample chamber 19, the light is changed into parallel light through the collimating objective 12 to irradiate into the cuvette 13, the cuvette 13 adopts a rear method, only the separated needed wavelength spectrum irradiates the sample, the sample passes through the cuvette 13 and is imaged by the imaging objective 14 and the optical filter 15, finally the sample enters the photocell sensor 16, the photocell sensor 16 serves as a final receiving device to receive the light processed by the whole set of optical paths, and the optical signals are converted into electrical signals and sent into an instrument electrical control system to complete signal detection.
The foregoing is illustrative of the best mode of carrying out the invention, and is not presented in any detail as is known to those of ordinary skill in the art. The protection scope of the invention is defined by the claims, and any equivalent transformation based on the technical teaching of the invention is also within the protection scope of the invention.
Claims (9)
1. The utility model provides a high accuracy infrared beam split oil survey appearance which characterized in that: the light source device comprises a light source chamber (17), a light splitting chamber (18) and a sample chamber (19) which are sequentially arranged, wherein an incident slit (5) is arranged at the joint of the light source chamber (17) and the light splitting chamber (18), the incident slit (5) is positioned in a first shading cylinder (6), an emergent slit (10) is arranged at the joint of the light splitting chamber (18) and the sample chamber (19), and the emergent slit (10) is positioned in a second shading cylinder (11);
a tungsten lamp (1) and a first plano-concave reflecting mirror (2) are arranged in the light source chamber (17), the tungsten lamp (1) is arranged close to the entrance slit (5), the tungsten lamp (1) is positioned at the side part of a connecting line between the entrance slit (5) and the first plano-concave reflecting mirror (2), and the tungsten lamp (1) is positioned at an intersection point of the outer diameter of a bulb of the tungsten lamp (1) outwards from the entrance slit (5) and the focal length of the first plano-concave reflecting mirror (2) which is twice;
the light splitting chamber (18) is of a square structure, a second plano-concave reflecting mirror (7), a grating (8) and a third plano-concave reflecting mirror (9) are arranged in the light splitting chamber (18), the second plano-concave reflecting mirror (7) is arranged on one side, far away from the light source chamber (17), of the light splitting chamber (18), the grating (8) is arranged between the incident slit (5) and the emergent slit (10), and the third plano-concave reflecting mirror (9) and the emergent slit (10) are arranged on two sides of a connecting line between the incident slit (5) and the second plano-concave reflecting mirror (7);
the first plano-concave reflecting mirror (2) collects and reflects light irradiated by the tungsten lamp (1) to the incident slit (5), the light transmitted through the incident slit (5) enters the light splitting chamber (18) to be irradiated to the second plano-concave reflecting mirror (7), the second plano-concave reflecting mirror (7) reflects the light to the grating (8) to split light, the light with different wavelengths is separated and irradiated to the third plano-concave reflecting mirror (9) through rotation of the grating (8), and the focused light enters the sample chamber (19) through the emergent slit (10).
2. The high-precision infrared spectroscopic oil meter of claim 1, wherein: the rear of the emergent slit (10) is sequentially provided with a collimating objective (12), a cuvette (13), an imaging objective (14), an optical filter (15) and a photocell sensor (16), and the center of the photocell sensor (16) and the center of the emergent slit (10) are on the same straight line.
3. The high-precision infrared spectroscopic oil meter of claim 1, wherein: the power of the tungsten lamp (1) is more than or equal to 20W; the cross section area of the filament of the tungsten lamp (1) is in a strip rectangular shape; the filament of the tungsten lamp (1) keeps vertical direction.
4. A high-precision infrared spectroscopic oil meter as set forth in claim 3 wherein: the rectangular hole shape and the length-width ratio of the incident slit (5) and the emergent slit (10) are the same as the cross section of the filament of the tungsten lamp (1); the width of the incident slit (5) is less than or equal to 0.5mm.
5. The high-precision infrared spectroscopic oil meter of claim 1, wherein: an air inlet fan (3) and an air outlet fan (4) which are arranged side by side are arranged on the side wall, far away from the light splitting chamber (18), of the light source chamber (17), an air channel is formed, and air flow is formed in the light source chamber (17).
6. The high-precision infrared spectroscopic oil meter of claim 1, wherein: the first shading cylinder (6) comprises a large-diameter cylinder and a small-diameter cylinder which are arranged in a collinear way, the lengths and the diameters of the large-diameter cylinder and the small-diameter cylinder are different, the small-diameter cylinder is positioned in the light source chamber (17), the large-diameter cylinder is positioned in the light splitting chamber (18), and the incident slit (5) is positioned in the end part of the small-diameter cylinder, which is close to the large-diameter cylinder.
7. The high-precision infrared spectroscopic oil meter of claim 6, wherein: the small diameter tube diameter D of the first shading tube (6) and the distance L from the tangent point A of the connecting line of the incident slit (5) and the outer diameter of the tungsten lamp (1) to the vertical plane where the incident slit (5) is positioned; the distance L1 between the first plano-concave reflecting mirror (2) and the incident slit (5), the diameter D1 of the first plano-concave reflecting mirror, the proportional equation is D1/L1=D/L, and the optimal dimension of the diameter D is calculated as D=L×D1/L1.
8. The high-precision infrared spectroscopic oil meter of claim 6, wherein: the diameter of a large diameter cylinder in the light splitting chamber (18) is D, the length of the large diameter cylinder is L, the distance from the edge of the third plano-concave reflecting mirror (9) to the vertical plane where the incident slit (5) is located is L1, the transverse distance D1 between the third plano-concave reflecting mirror (9) and the incident slit (5) is D1/L1=D/L, and the optimal size of the diameter D is calculated to be D=LxD1/L1.
9. The high-precision infrared spectroscopic oil meter of claim 1, wherein: the distance between the incident slit (5) and the second plano-concave reflecting mirror (7) is equal to the focal length of the second plano-concave reflecting mirror (7), the second plano-concave reflecting mirror (7) is inclined at a certain angle, the second plano-concave reflecting mirror (7) emits light into the grating (8) in parallel, the grating (8) rotates along the center of the grating, and diffracted light is directed to the third plano-concave reflecting mirror (9) through rotation of the grating.
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| CN101672767A (en) * | 2009-09-01 | 2010-03-17 | 深圳市蓝韵实业有限公司 | Grating spectrophotometer |
| JP2010197310A (en) * | 2009-02-26 | 2010-09-09 | Toyota Motor Corp | Optical chopper and optical analyzer |
| CN203037572U (en) * | 2013-01-18 | 2013-07-03 | 上海元析仪器有限公司 | Optical system of spectrophotometer |
| JP2015001424A (en) * | 2013-06-14 | 2015-01-05 | 株式会社日立ハイテクノロジーズ | Spectrophotometer |
| JP2016095258A (en) * | 2014-11-17 | 2016-05-26 | 横河電機株式会社 | Optical device and measuring apparatus |
| CN211318892U (en) * | 2019-12-31 | 2020-08-21 | 长春长光格瑞光电技术有限公司 | Flat field concave surface light splitting module |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US7564549B2 (en) * | 2006-05-09 | 2009-07-21 | Ada Technologies | Carbon nanotube nanometrology system |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010197310A (en) * | 2009-02-26 | 2010-09-09 | Toyota Motor Corp | Optical chopper and optical analyzer |
| CN101672767A (en) * | 2009-09-01 | 2010-03-17 | 深圳市蓝韵实业有限公司 | Grating spectrophotometer |
| CN203037572U (en) * | 2013-01-18 | 2013-07-03 | 上海元析仪器有限公司 | Optical system of spectrophotometer |
| JP2015001424A (en) * | 2013-06-14 | 2015-01-05 | 株式会社日立ハイテクノロジーズ | Spectrophotometer |
| JP2016095258A (en) * | 2014-11-17 | 2016-05-26 | 横河電機株式会社 | Optical device and measuring apparatus |
| CN211318892U (en) * | 2019-12-31 | 2020-08-21 | 长春长光格瑞光电技术有限公司 | Flat field concave surface light splitting module |
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