Long-optical-path gas absorption cell
By designing a closed annular cross-section and a structure of spliced mirrors and plane mirrors in the gas absorption tank, the problems of volume increase and gas demand in the previous technology are solved, and efficient and fast gas detection is achieved.
Patent Information
- Application Number
- CN202421722287.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-07-19
AI Technical Summary
While pursuing a long optical path, the existing gas absorption tanks have increased their volume and increased the gas demand, making it difficult to meet the needs of efficient detection in industrial production process monitoring.
A long-path gas absorption cell is designed, by forming a closed annular cross-section between the shell and the tube body, combining the structure of splicing mirrors and planar mirrors, so that the detected light is reflected multiple times on the surface of the positive prism, extending the laser light path and reducing the gas demand.
It achieves a balance between long optical path and low gas demand, reduces sampling time, improves detection speed and accuracy, and reduces production costs.
Smart Images
Figure CN222994310U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of gas detection equipment, in particular to a long optical path gas absorption cell. Background Technique
[0002] The optical gas absorption cell combined with tunable diode laser absorption spectroscopy (TDLAS) technology is a commonly used method for detecting gas concentration and composition. According to the development requirements of TDLAS technology, current gas absorption cells have a development trend of long optical path, miniaturization, easy operation, high stability, and simultaneous measurement of multiple gases.
[0003] The long optical path gas cell is mainly applied in the fields of air pollution research, environmental monitoring, gas purity analysis, industrial production process monitoring, exhaust gas analysis, and oil exploration geological logging process monitoring, etc.; among which, industrial production process monitoring includes the application scenario of detecting trace gas leakage of pipeline products. Such application scenarios require on-site sampling and also require that the detection speed and real-time performance must be high enough. Therefore, it is required that the gas cell not only needs a long optical path to improve the detection accuracy, but also needs a low gas demand to reduce the sampling time and improve the detection speed.
[0004] The existing Herriott-type absorption cell has the advantage of a long optical path, but when pursuing a large optical path, it will cause the volume of the absorption cell to increase rapidly, thus increasing the gas demand. The annular absorption cell has the advantage of a small volume, but its mirror surface processing is difficult and the optical path is usually small.
[0005] Therefore, it is urgent to design a gas absorption cell with both a long optical path and a low gas demand. Summary of the Utility Model
[0006] Aiming at the problems existing in the background technique, the utility model proposes a gas absorption cell with both a long optical path and a low gas demand, so as to reduce the sampling time of industrial production process monitoring and improve the detection speed.
[0007] The technical solution of the utility model: A long optical path gas absorption cell, comprising a housing and a tube body, the tube body passes through the housing to form a gas cell with a closed annular cross-section, one end of the gas cell is provided with an air inlet, and the other end is provided with an air outlet. Its characteristics are that it further includes a splicing mirror and a plane mirror.
[0008] The spliced mirror and the plane mirror are respectively arranged inside the two top ends of the gas cell. A light passing hole is formed in the plane mirror, and the housing is provided with a light incident hole matching the light passing hole. After the detection light enters the gas cell through the light incident hole and the light passing hole, it is reflected back and forth between the spliced mirror and the plane mirror for multiple times, and finally exits from the light incident hole and the light passing hole. There is an included angle between the incident light and the outgoing light, and the optical path of the detection light remains on the surface of a regular prism throughout the whole process from incidence to exit.
[0009] Preferably, bases are provided at both ends of the housing, and the two bases are connected by a connecting rod to be in a coaxial state.
[0010] Preferably, through holes are provided on the surfaces of both bases, and the two ends of the tube body are respectively fixed in the through holes.
[0011] Preferably, the spliced mirror includes a spliced mirror base and a plurality of spliced mirror units. The plurality of spliced mirror units are evenly arranged on the spliced mirror base, and the mirror surfaces of the spliced mirror units face the plane mirror.
[0012] Preferably, there is an included angle between the surface of the spliced mirror unit and the surface of the spliced mirror base, so that after the detection light hits the spliced mirror unit, it can be reflected from one surface of the regular prism to the next adjacent surface, and then the light reaches the plane mirror. Then the plane mirror reflects the detection light, so that the detection light still propagates along the surface of the regular prism where it is incident, and so on until the light exits.
[0013] Compared with the prior art, the utility model has the following beneficial technical effects:
[0014] The utility model conveys the gas to be detected into the gas cell through the air inlet, and forms a gas cell with a closed annular cross-section between the tube body and the housing, thereby greatly reducing the volume of the gas cell and effectively reducing the gas demand for filling the absorption cell.
[0015] Furthermore, by arranging the spliced mirror and the plane mirror facing each other on the inner sides of the two end faces of the cylindrical hollow tube, after the detection light source is input, it can be reflected multiple times between the spliced mirror and the plane mirror along the surface of the regular prism, which is beneficial to extending the laser optical path and improving the detection accuracy; and both the plane mirror and the spliced mirror unit are plane mirrors, which reduces the production cost. Description of the Drawings
[0016] Figure 1 It is a schematic structural diagram of the long optical path gas absorption cell in the embodiment of the utility model;
[0017] Figure 2Schematic diagram of the first perspective of the long optical path gas absorption cell without the housing in the embodiment of the present utility model;
[0018] Figure 3 Schematic diagram of the second perspective of the long optical path gas absorption cell without the housing in the embodiment of the present utility model;
[0019] Figure 4 Optical path conduction diagram between the spliced mirror and the plane mirror in the embodiment of the present utility model;
[0020] Figure 5 Schematic structural diagram of the spliced mirror in the embodiment of the present utility model.
[0021] Reference numerals: 1 is the spliced mirror, 101 is the spliced mirror unit, 102 is the spliced mirror base, 2 is the plane mirror, 201 is the light passing hole, 3 is the tube body, 301 is the air inlet, 302 is the air outlet, 4 is the housing, 410 is the base, 411 is the light inlet hole, 420 is the connecting rod. Detailed implementation manners
[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.
[0023] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "upright", "transverse", "inner", "outer", "front", "back", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present utility model.
[0024] As Figures 1 to 5 shown, an embodiment of the present utility model provides a long optical path gas absorption cell, which includes a housing 4 and a tube body 3. The tube body 3 passes through the housing, and a sealed annular cross-section gas cell is formed between the two. One end of the gas cell is provided with an air inlet, and the other end is provided with an air outlet, that is, they are respectively arranged at both ends of the tube body 3. In this embodiment, the air inlet and the air outlet are arranged radially. The long optical path gas absorption cell further includes a spliced mirror 1 and a plane mirror 2.
[0025] In this embodiment, the spliced mirror 1 and the plane mirror 2 are respectively arranged inside the two top ends of the gas cell.
[0026] SeeFigure 4 , a light passing hole 201 is provided on the plane mirror 2, and a light incident hole 411 matching the light passing hole 201 is provided on the housing; so that the detection light enters the gas cell through the light incident hole 411 and the light passing hole 201, and is reflected back and forth between the splicing mirror 1 and the plane mirror 2 for multiple times, and finally exits from the light incident hole 411 and the light passing hole 201 again. There is an included angle between the incident light and the outgoing light, and the whole process of the optical path of the detection light from incidence to exit always remains on the surface of a regular prism.
[0027] During use, the gas to be detected is transported into the gas cell through the gas inlet 301. The gas cell is arranged between the tube body 3 and the housing 4, greatly reducing the volume of the gas cell, thereby effectively reducing the gas demand for filling the absorption cell;
[0028] Furthermore, by setting the splicing mirror 1 and the plane mirror 2, after the laser is input, it can be reflected multiple times between the splicing mirror 1 and the plane mirror 2, which is beneficial to extending the laser optical path and improving the detection accuracy; both the plane mirror 2 and the splicing mirror unit 101 are plane mirrors, reducing the production cost.
[0029] In this embodiment, bases 410 are provided at both ends of the housing 4, and the two bases 410 are connected by a connecting rod 420 to be in a coaxial state.
[0030] In this embodiment, the base 410 is triangular, and connecting rods 420 are respectively arranged at the ends of the triangle for connecting the base 410. The housing 4 is arranged between the bases 410, and its two ends are fixed on the bases 410.
[0031] In this embodiment, the splicing mirror 1 includes a splicing mirror base 102 and a plurality of splicing mirror units 101. The plurality of splicing mirror units 101 are evenly arranged on the splicing mirror base 102. The mirror surface of the splicing mirror unit 101 faces the plane mirror 2, and there is an included angle between the surface of the splicing mirror unit 101 and the surface of the splicing mirror base 102, so that after the detection light hits the splicing mirror unit 101, it can be reflected from one surface of the regular prism to the next adjacent surface, and then the light reaches the plane mirror 2. Then the plane mirror 2 reflects the detection light, so that the detection light still propagates along the surface of the regular prism where it is incident when it enters, and so on until the light exits. This structure greatly extends the optical path of the laser, thereby improving the detection accuracy. Those skilled in the art can set the distance between the splicing mirror 1 and the plane mirror 2, the number of splicing mirror units 101 on the splicing mirror 1, and the included angle between the surface of the splicing mirror unit 101 and the splicing mirror base 102 according to needs when knowing the optical path of the detection light, as well as the setting positions and mirror body structures of the splicing mirror 1 and the plane mirror 2. The specific implementation will not be elaborated here.
[0032] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "setting" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0033] The above specific embodiments are merely one or several preferred embodiments of the present utility model. Based on the technical solution of the present utility model and the relevant revelations of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.
Claims
1. A long optical path gas absorption cell, comprising a shell and a tube body, wherein the tube body passes through the shell to form a closed annular cross-section gas cell, wherein one end of the gas cell is provided with an air inlet and the other end is provided with an air outlet, characterized in that: Also included are spliced reflectors and flat reflectors; The spliced reflector and the plane reflector are respectively arranged on the inner sides of the two top ends of the gas pool, a light through hole is opened on the plane reflector, and the shell is provided with a light inlet hole matching the light through hole; so that after the detection light is emitted into the gas pool through the light inlet hole, it is reflected back and forth between the spliced reflector and the plane reflector for many times, and finally emitted from the light inlet hole and the light through hole, there is an angle between the incident light and the emitted light, and the optical path of the detection light is always maintained on the surface of a regular prism throughout the entire process from incidence to emission.
2. A long optical path gas absorption cell according to claim 1, characterized in that: Bases are provided at both ends of the shell, and the two bases are connected by a connecting rod so as to be in a coaxial state.
3. A long optical path gas absorption cell according to claim 2, characterized in that: The surfaces of the two bases are both provided with through holes, and the two ends of the tube body are respectively fixed in the through holes.
4. The long optical path gas absorption cell according to claim 1, characterized in that: The spliced reflector comprises a spliced reflector base and a plurality of spliced reflector units. The plurality of spliced reflector units are evenly arranged on the spliced reflector base, and the mirror surfaces of the spliced reflector units face the plane reflector.
5. A long optical path gas absorption cell according to claim 4, characterized in that: The surface of the spliced reflector unit and the surface of the spliced reflector base have an angle, so that after the detection light hits the spliced reflector unit, it can be reflected from one surface of the regular prism to the next adjacent surface, and then the light reaches the plane reflector, and then the plane reflector reflects the detection light, so that the detection light still propagates along the surface of the regular prism where it is incident, and this is repeated until the light is emitted.