Long-optical-path gas absorption cell easy to install and maintain

Abstract

The utility model relates to the technical field of waste gas monitoring equipment, in particular to a long-optical-path gas absorption cell easy to install and maintain, which comprises an absorption cell body, two ends of the absorption cell body are respectively provided with a lens mechanism and a reflector mechanism through positioning pins, and the side surface of the absorption cell body is also provided with two universal barb type gas path interfaces; the lens mechanism comprises a lens end cover, the one-third position of one side of the lens end cover is an inclined face, and an inclined installation opening is formed in the inclined face. An incident light path of the absorption cell body is consistent, a light source, a spectrograph and the absorption cell can be connected through a one-to-two optical fiber patch cord, a lens mechanism and a reflector mechanism are installed in a positioning pin installation mode, optical devices are fewer, the size is smaller, structural optimization of the whole machine is facilitated, rapid disassembly, assembly and maintenance are achieved, and the installation efficiency is improved. Meanwhile, the manufacturing cost and the debugging difficulty are lower, the number of times of turning back of the reflector is increased to 7, the optical path reaches 14 * 300mm, and the sensitivity and the accuracy of ultralow-range gas detection are remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to waste gas monitoring equipment technical field, concretely is an easily installed and maintained long optical path gas absorption cell. BACKGROUND

[0002] With the increasing environmental protection requirement, the waste gas emission requirement is continuously improved, and the ultra-low range environmental protection monitoring instrument gradually becomes the market mainstream, and gases such as NO2 gradually become the tail gas monitoring focus. The ultra-low range environmental protection monitoring instrument mainly adopts long optical path gas absorption cell, and the long optical path gas absorption cell on the current market can be roughly divided into White cell, Herr i ott cell and CMR cell, the above scheme all adopts the method that optical element reflects light beam multiple times to improve the optical path to realize ultra-low range environmental protection monitoring. Based on the White cell, there are many designs to increase the optical path, such as CN113484266A, which increases the multiplication mirror on the basis of the traditional typical White cell optics, thereby increasing the optical path, not only increasing the optical structure volume, but also increasing the manufacturing cost and artificial debugging difficulty. UTILITY MODEL CONTENT

[0003] In order to achieve the above purpose, the utility model provides the following technical scheme: an easily installed and maintained long optical path gas absorption cell, which comprises an absorption cell body, lens mechanisms and mirror mechanisms are installed at both ends of the absorption cell body through positioning pins, and two universal barb type gas port interfaces are further arranged on the side surface;

[0004] The lens mechanism comprises a lens end end cover, one side of the lens end end cover is inclined by one third, an inclined mounting hole is formed in the inclined surface, a rectangular concave mirror and an ultraviolet lens sealing the mounting hole are installed on the other side of the lens end end cover, and a fiber adjuster is installed in the mounting hole through a positioning structure;

[0005] The mirror mechanism comprises a mirror end end cover, an inner cavity is formed in one side of the mirror end end cover, a mirror adjusting frame is fixed in the inner cavity through locking screws, two groups of circular grooves are formed in the mirror adjusting frame, and a circular concave mirror is installed in the circular grooves.

[0006] Further, the fiber adjuster is in the form of a boss, and is divided into a convex column and a disc, the convex column is matched with the mounting hole, and the disc is attached to the inclined surface of the lens end end cover.

[0007] Further, the mounting hole of the ultraviolet lens on the lens end end cover has a 2.5° inclination angle relative to the optical axis, and the mounting base surface of the fiber adjuster has a 7° inclination angle relative to the same optical axis.

[0008] Further, the positioning structure comprises three groups of through holes formed on the optical fiber adjuster, the lens end cap is provided with locking holes opposite to the through holes in the inclined surface, and the through holes are provided with adjusting rings matched with the locking holes, and the adjusting rings are provided with mounting screws threadedly connected with the locking holes.

[0009] Further, the middle part of the mirror adjustment frame is provided with a T-shaped groove extending outward, the two ends of the cross section of the T-shaped groove are in a cylindrical shape, and the front surface of the mirror adjustment frame is provided with adjusting holes communicated with the T-shaped groove at opposite corners, and the adjusting holes are provided with adjusting screws threadedly connected with the inner side of the mirror adjustment frame.

[0010] Further, the curvature radii of the circular concave mirror and the rectangular concave mirror are the same, and are 300 mm, and the distance between the circular concave mirror and the rectangular concave mirror in the optical axis direction is the same as the curvature radius.

[0011] Compared with the prior art, the technical scheme has the following beneficial effects:

[0012] 1. The absorption cell body is consistent with the incident light path, and can be connected with a light source, a spectrometer and an absorption cell through a one-to-two optical fiber jumper, optical devices such as a lens mechanism and a mirror mechanism are installed through a positioning pin installation mode, the volume is smaller, the structure optimization of the whole machine is facilitated, rapid disassembly and maintenance are realized, the installation efficiency is improved, the manufacturing cost and the debugging difficulty are lower, the number of mirror return is increased to 7 times, the optical path is 14*300 mm, and the sensitivity and accuracy of ultra-low range gas detection are significantly improved.

[0013] 2. The curvature radii of the circular concave mirror and the rectangular concave mirror are 300 mm, and the distance between the optical axes is consistent with the curvature radius, so that the stability of the light path and the energy utilization rate are ensured.

[0014] 3. The mirror adjustment frame is combined with a T-shaped groove and an adjusting screw, the lens mechanism is adjusted through the inclination design and three groups of positioning screws, precise calibration is realized, and the debugging difficulty is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a structural schematic view of the utility model;

[0016] Figure 2 It is an exploded schematic view of the lens mechanism in the utility model;

[0017] Figure 3 It is an exploded schematic view of the mirror mechanism in the utility model;

[0018] Figure 4 It is a light path diagram of the utility model.

[0019] In the figure: 1, the absorption cell body; 2, the lens mechanism; 21, the lens end cap; 22, the mounting port; 23, the locking hole; 24, the optical fiber adjuster; 25, the adjusting ring; 26, the mounting screw; 27, the through hole; 28, the ultraviolet lens; 29, the rectangular concave mirror; 3, the mirror mechanism; 31, the mirror end cap; 32, the inner cavity; 33, the mirror adjusting frame; 34, the T-shaped groove; 35, the circular groove; 36, the adjusting hole; 37, the circular concave mirror; 38, the locking screw; 39, the adjusting screw; 4, the gas path interface. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0021] Please refer to Figures 1-4 The long optical path gas absorption cell easy to install and maintain in the embodiment comprises an absorption cell body 1, lens mechanisms 2 and mirror mechanisms 3 are fixed to the left and right ends of the absorption cell body 1 through positioning pins, and two groups of universal type barb type gas path interfaces 4 are mounted on the top of the absorption cell body 1.

[0022] In the above structure, the light ray in and out path of the absorption cell body is consistent, the light ray is incident from the lens mechanism, is reflected multiple times through the mirror mechanism and is emitted from the original path, the independent adjustment of the emitted light path is not needed, the number and complexity of optical elements are reduced, the multiple reflection design greatly increases the optical path in the limited space, the detection sensitivity is improved, and the long optical path gas absorption cell is especially suitable for low concentration gas analysis. The lens mechanisms and the mirror mechanisms are installed in the form of the positioning pin installation mode, the optical devices are less and smaller, the machine structure optimization is beneficial, rapid disassembly, assembly and maintenance are realized, the installation efficiency is improved, the manufacturing cost and the debugging difficulty are lower, the number of times of turning back of the mirror mechanism is increased to 7, the optical path is 14*300mm, and the sensitivity and accuracy of the ultra-low range gas detection are significantly improved.

[0023] As Figure 2The lens mechanism 2 comprises a lens end cover 21 installed on the left end of the absorption cell body 1 by a positioning pin. The lens end cover 21 is a cuboid, and the front surface of the lens end cover 21 is cut into an inclined surface at the right side. The front surface of the lens end cover 21 is provided with an inclined installation opening 22 at the center of the inclined surface. An optical fiber adjuster 24 is installed in the installation opening 22 by a positioning structure. The optical fiber adjuster 24 is a boss type and is divided into a convex column and a disc. The convex column is matched with the installation opening 22, and the disc is attached to the inclined surface of the lens end cover 21, so that the installation base surface of the optical fiber adjuster 24 is inclined at an angle of 7° with respect to the same reference optical axis. An ultraviolet lens 28 and a rectangular concave mirror 29 are installed on the back surface of the lens end cover 21 by ultraviolet curing. The ultraviolet lens 28 seals the installation opening 22, and the installation hole of the ultraviolet lens 28 on the lens end cover 21 is inclined at an angle of 2.5° with respect to the optical axis.

[0024] The optical fiber adjuster is installed at an angle of 7°, so that the incident light and the reflected light deviate from the original path, significantly reducing the interference of the back reflection light on the light source or the optical fiber, improving the signal-to-noise ratio. The boss type design is closely attached to the inclined surface by the positioning structure, ensuring that the optical fiber end surface is accurately aligned with the optical axis, reducing installation errors and improving coupling efficiency. The convex column is matched with the installation opening and the disc is attached, enhancing the anti-vibration ability, suitable for high-precision experimental environment. The installation hole of the ultraviolet lens is inclined at an angle of 2.5° with respect to the optical axis, which can deflect the stray light generated by internal reflection and avoid entering the detector, improving the detection accuracy. The ultraviolet lens seals the installation opening, which not only prevents dust and pollution, but also avoids gas leakage, while allowing efficient transmission of ultraviolet light. The rectangular concave mirror reflects the light path back, shortening the overall structure length while keeping the optical path unchanged, suitable for space-limited applications. The concave design of the rectangular concave mirror can correct aberration or focus the light beam, improve the uniformity of ultraviolet light in the absorption cell, and enhance the detection sensitivity.

[0025] The positioning structure comprises three groups of through holes 27 arranged in a triangular distribution on the disc of the optical fiber adjuster 24. The lens end cover 21 is provided with locking holes 23 on the inclined surface, which are opposite to the number of through holes 27. An adjusting ring 25 is arranged in the through hole 27. The adjusting ring 25 is provided with a mounting screw 26 threadedly connected with the locking hole 23.

[0026] The through holes and locking holes are in a triangular distribution, and through locking by the mounting screws, the stress balance of the optical fiber adjuster is ensured, the deflection caused by one-side locking is avoided, the fitting degree of the installation plane and the inclined plane is improved, and at the same time, fine adjustment can also be realized through one-side locking. The adjusting ring acts as an intermediate sleeve, and can allow the optical fiber adjuster to slightly translate or rotate before the mounting screws are tightened, so that the optical axis is aligned. After the mounting screws are connected with the locking holes in a threaded manner, the triangular layout forms multi-point constraint, the anti-vibration performance is strong, and the optical fiber adjuster is suitable for a dynamic environment. The through holes and the locking holes are in one-to-one correspondence, and during assembly, complex alignment is not needed, and the optical fiber adjuster can be preliminarily fixed only by inserting the mounting screws, so that the installation difficulty is reduced. The adjusting ring protects the through holes of the optical fiber adjuster from direct friction of the screws, and prolongs the service life.

[0027] As Figure 3 , the mirror mechanism 3 includes a mirror end cover 31 installed on the right side of the absorption cell body 1 through a positioning pin. The front surface of the mirror end cover 31 is provided with a rectangular inner cavity 32. Four sets of locking screws 38 are arranged in the inner cavity 32 to fix a mirror adjusting frame 33. Two circular grooves 35 are arranged on the front surface of the mirror adjusting frame 33. A circular concave mirror 37 is arranged in the circular grooves 35 through ultraviolet curing.

[0028] The locking screws ensure that the mirror adjusting frame is balanced in the inner cavity, and deformation caused by one-side stress is avoided. The angle of the circular concave mirror can be adjusted by loosening some of the screws, and the optical path can be calibrated and then locked again, which is suitable for high-precision optical systems. The circular concave mirror is embedded in the circular groove 35, so that the optical axis is aligned with the center of the mirror, and the installation deviation is reduced. Through reflection and return of the optical path, the absorption optical path can be extended in a limited space, which is suitable for a multiple reflection absorption cell and improves the detection sensitivity.

[0029] The radius of curvature of the circular concave mirror 37 and the rectangular concave mirror 29 is 300 mm, and the distance between the circular concave mirror 37 and the rectangular concave mirror 29 in the optical axis direction is the same as the radius of curvature. After being reflected twice, the light beam returns along the original path, which significantly simplifies the difficulty of optical path calibration. Even if the angle of the mirror is slightly adjusted, the light beam can still maintain a stable path. The confocal structure can suppress the divergence of the light beam, so that the size change of the light spot is minimized when the light spot is reflected between the mirrors. The design is suitable for an absorption cell with a long optical path, such as a multiple reflection cell. When the curvatures of the two mirrors are the same and confocal, the spherical aberration and coma are offset, the light beam quality is improved, the size of the outgoing light spot is controlled, and the light throughput of the entire system is improved.

[0030] In addition, the middle part of the mirror adjusting frame 33 is provided with a T-shaped groove 34 extending to the front, the left and right ends of the T-shaped groove 34 in the inside of the mirror adjusting frame 33 are in a cylindrical shape, and the four corners of the front of the mirror adjusting frame 33 are provided with adjusting holes 36 communicating with the T-shaped groove 34, four adjusting screws 39 are arranged in the adjusting holes 36 and are screwed with the inside of the mirror adjusting frame 33, and the circular groove 35 is not communicated with the T-shaped groove 34.

[0031] The angle of the circular concave mirror can be adjusted according to the needs by adjusting the screw to be tightened to extrude the mirror adjusting frame.

[0032] The whole work flow is ended, and the contents not described in detail in the specification all belong to the prior art known by the professional technical personnel in the field.

[0033] It should be noted that the relational terms herein such as first and second and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any such actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element preceded by "comprises... a" does not, without more limitations, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the recited element.

[0034] Although the embodiments of the present application have been shown and described, it should be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made thereto without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A long optical path gas cell which is easy to install and maintain, characterized in that: It includes an absorption cell body (1), the two ends of the absorption cell body (1) are respectively provided with a lens mechanism (2) and a mirror mechanism (3) through positioning pins, and two universal barb type gas interfaces (4) are arranged on the side surface; The lens mechanism (2) comprises a lens end cover (21), one side of the lens end cover (21) is provided with an inclined surface, and an inclined installation opening (22) is arranged on the inclined surface; the other side of the lens end cover (21) is respectively provided with an oblong concave mirror (29) and an ultraviolet lens (28) sealing the installation opening (22); and a fiber adjuster (24) is arranged in the installation opening (22) through a positioning structure. The mirror mechanism (3) comprises a mirror end cover (31), one side of the mirror end cover (31) is provided with an inner cavity (32), and a mirror adjusting frame (33) is fixed in the inner cavity (32) through locking screws (38); two groups of circular grooves (35) are arranged on the mirror adjusting frame (33), and a circular concave mirror (37) is arranged in the circular grooves (35).

2. A long optical path gas cell easy to install and maintain according to claim 1, characterized in that: The fiber adjuster (24) is in a boss type and is divided into a convex column and a disc, the convex column is matched with the installation opening (22), and the disc is attached to the inclined surface of the lens end cover (21).

3. A long optical path gas cell easy to install and maintain according to claim 2, characterized in that: An installation hole of the ultraviolet lens (28) on the lens end cover (21) has an inclination of 2.5° with respect to an optical axis, and an installation base surface of the fiber adjuster (24) has an inclination of 7° with respect to the same optical axis.

4. A long optical path gas cell easy to install and maintain according to claim 1, characterized in that: The positioning structure comprises three groups of through holes (27) arranged on the fiber adjuster (24), the lens end cover (21) is provided with locking holes (23) on the inclined surface, the locking holes (23) are opposite to the through holes (27) and have the same number as the through holes (27), an adjusting ring (25) is arranged in the through holes (27), and an installation screw (26) is arranged in the adjusting ring (25) and is threadedly connected with the locking hole (23).

5. A long optical path gas cell easy to install and maintain according to claim 4, characterized in that: A T-shaped groove (34) extending outward is arranged in the middle of the mirror adjusting frame (33), the two ends of the cross section of the T-shaped groove (34) are in a cylindrical shape, adjusting holes (36) are arranged in the opposite corners of the front surface of the mirror adjusting frame (33) and are communicated with the T-shaped groove (34), and adjusting screws (39) are arranged in the adjusting holes (36) and are threadedly connected with the inner side of the mirror adjusting frame (33).

6. A long optical path gas cell easy to install and maintain according to claim 1, characterized in that: The curvature radii of the circular concave mirror (37) and the oblong concave mirror (29) are the same, and the curvature radii are 300 mm; and the distance between the circular concave mirror (37) and the oblong concave mirror (29) in the direction of the optical axis is the same as the curvature radii.

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