Gas concentration detection device

Abstract

The utility model relates to the technical field of gas concentration detection, and provides a gas concentration detection device which comprises a base and a resonant cavity arranged on the base, and further comprises a first Booth window and a second Booth window which are fixedly arranged at the incident end and the emergent end of the resonant cavity respectively, window lenses are glued and sealed on the first Booth window and the second Booth window, and a multi-stage sealing structure is arranged between the incident end and the first Booth window and a multi-stage sealing structure is arranged between the emergent end and the second Booth window. According to the gas concentration detection device disclosed by the utility model, the light incident end and the light emergent end of the resonant cavity are sealed by adopting multi-stage sealing fit, so that complete sealing of the resonant cavity can be realized, and the detection device can realize 10-9 (PPB)-level concentration detection.

Description

TECHNICAL FIELD

[0001] The utility model relates to gas concentration detection technical field, concretely is a kind of gas concentration detection device. BACKGROUND

[0002] The reliability of the existing device for detecting gas concentration using optical cavity ring-down spectroscopy technology is greatly related to the sealing of the resonant cavity.If the sealing of the resonant cavity is not good enough, the laser oscillation in the resonant cavity will be affected by the gas concentration in the ambient air outside the cavity, and the reliability and reproducibility are not high.Especially, as the detection accuracy of the detection device increases, the requirement for sealing also increases.However, due to the shape limitation of the resonant cavity, the sealing is affected, so the reliability of the existing device for detecting gas concentration using optical cavity ring-down spectroscopy technology is not very high. SUMMARY

[0003] The utility model aims at providing a kind of gas concentration detection device, at least can solve part of defects in prior art.

[0004] To achieve the above object, the utility model embodiment provides the following technical scheme: a kind of gas concentration detection device, including base and the resonant cavity being located on the base, further including the first Bus window and the second Bus window respectively fixedly installed in the incident end and the emission end of the resonant cavity, window lens is sealed with glue on the first Bus window and the second Bus window, and multiple-stage sealing structure is arranged between the incident end and the first Bus window and between the emission end and the second Bus window.

[0005] Further, the multiple-stage sealing structure includes first-stage sealing gasket clamped between the first Bus window and the incident end and between the second Bus window and the emission end, and the first-stage sealing gasket is annular structure.

[0006] Further, a plurality of perforations are provided on the first-stage sealing gasket, and each perforation is uniformly and spacedly arranged along the circumferential direction of the first-stage sealing gasket.

[0007] Further, the multiple-stage sealing structure includes second-stage sealing ring embedded in the annular groove of the resonant cavity.

[0008] Further, the multiple-stage sealing structure includes third-stage sealing washer, a plurality of screw holes are provided on the first Bus window and the second Bus window, the first Bus window and the incident end are fixed by screwing the screw holes, and the second Bus window and the emission end are fixed by screwing the screw holes, and the third-stage sealing washer is sleeved on the screw.

[0009] Further, it further includes a laser, and the laser is arranged on one side of the incident end of the resonant cavity.

[0010] Further, the laser emitted by the laser is reflected to the first Brewster window through the first mirror and the second mirror, and the first mirror and the second mirror are both arranged at an angle of 45°, so that the laser emitted by the laser is arranged in parallel with the laser incident on the first Brewster window.

[0011] Further, the incident end of the resonant cavity is provided with an incident high reflection mirror, and the emission end of the resonant cavity is provided with an emission high reflection mirror.

[0012] Further, the incident high reflection mirror and the emission high reflection mirror are both fixed in the resonant cavity through a mirror holder.

[0013] Further, the emission end of the resonant cavity is further provided with a focusing lens.

[0014] Compared with the prior art, the beneficial effects of the utility model are that: a gas concentration detection device adopts multi-stage sealing cooperation to seal the light incident end and the light emission end of the resonant cavity, can realize complete sealing of the resonant cavity, so that the detection device can realize concentration detection of 10 -9 (PPb) level. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a first perspective view schematic drawing of a gas concentration detection device provided by the utility model embodiment;

[0016] Figure 2 It is a second perspective view schematic drawing of a gas concentration detection device provided by the utility model embodiment;

[0017] Figure 3 It is an assembly schematic drawing of the resonant cavity, the first Brewster window and the second Brewster window of a gas concentration detection device provided by the utility model embodiment;

[0018] Figure 4 It is a local enlarged schematic drawing of the incident end of the resonant cavity of a gas concentration detection device provided by the utility model embodiment;

[0019] Figure 5 It is Figure 4 It is an enlarged schematic drawing without the first Brewster window;

[0020] Figure 6 It is Figure 5 It is a schematic drawing without the screw;

[0021] Figure 7 It is an assembly schematic drawing of the incident high reflection mirror, the mirror holder, the first-stage sealing gasket, the second-stage sealing ring of the incident end of the resonant cavity of a gas concentration detection device provided by the utility model embodiment;

[0022] Figure 8 A first view angle assembly schematic view of an outgoing high reflection mirror, a mirror frame, a first level sealing gasket, a second level sealing ring and a screw of an outgoing end of a resonant cavity of a gas concentration detection device is provided for the utility model embodiment;

[0023] Figure 9 A second view angle assembly schematic view of an outgoing high reflection mirror, a mirror frame, a first level sealing gasket, a second level sealing ring and a screw of an outgoing end of a resonant cavity of a gas concentration detection device is provided for the utility model embodiment;

[0024] In the drawing marks: 1 - base; 2 - resonant cavity; 20 - incoming end; 21 - outgoing end; 22 - incoming high reflection mirror; 23 - outgoing high reflection mirror; 24 - mirror frame; 25 - focusing lens; 30 - first Bus window; 31 - second Bus window; 32 - window lens; 40 - first level sealing gasket; 41 - second level sealing ring; 42 - third level sealing washer; 43 - screw; 50 - collimating seat; 51 - first reflecting mirror; 52 - second reflecting mirror; 53 - photoelectric detector. DETAILED DESCRIPTION

[0025] The technical scheme in the utility model embodiments will be described clearly and completely below with reference to the drawings in the utility model embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model and not 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 scope of protection of the utility model.

[0026] Please refer to Figures 1 to 9 The utility model embodiment provides a kind of gas concentration detection device, including base 1, be located on the resonant cavity 2 of the base 1 and the first Bus window 30 and second Bus window 31 respectively fixedly installed in the incoming end 20 and outgoing end 21 of the resonant cavity 2, the first Bus window 30 and the second Bus window 31 are all glued and sealed with window lens 32, the incoming end 20 and the first Bus window 30 between and the outgoing end 21 and the second Bus window 31 between are equipped with multistage sealing structure.In this embodiment, the light incoming end 20 and light outgoing end 21 of resonant cavity 2 are sealed with multistage sealing cooperation, the complete sealing of resonant cavity 2 can be realized, so that the detection device can realize 10 -9(PPb) level concentration detection. Specifically, a first Busch window 30 and a second Busch window 31 are respectively provided at the incident end 20 and the exit end 21 of the resonant cavity 2. The Busch window can improve the light transmittance. Its window lens 32 is sealed to the light port of the Busch window by adhesive, thereby achieving a seal on the Busch window. Then, a multi-level sealing structure is used to complete the seal between the Busch window and the resonant cavity 2. In this way, the incident end 20 and the exit end 21 of the resonant cavity 2 can be completely sealed.

[0027] For a more detailed explanation of the multi-stage sealing structure described above, please refer to [link / reference]. Figures 1 to 9 Specifically, the sealing can be divided into three levels. The first level of sealing uses a first-level sealing gasket 40, which can be sandwiched between the first Bus window 30 and the incident end 20, and between the second Bus window 31 and the exit end 21. This eliminates the gap between the Bus window and the port of the resonant cavity 2 along the axial direction, thus completing the seal at this point. Preferably, the first-level sealing gasket 40 has several perforations, which are evenly spaced along the circumferential direction of the first-level sealing gasket. These perforations facilitate the installation of screws 43. Next, the second level of sealing uses a second-level sealing ring 41, which is disposed in the annular groove on the edge of the resonant cavity 2. The second-level sealing ring 41 can be perfectly embedded in the annular groove, thereby satisfying the sealing performance of the edge of the resonant cavity 2. Next, the third-stage seal uses a third-stage sealing gasket 42. There are multiple third-stage sealing gaskets 42, matching the number of screws 43. This is because leakage can occur at the screws 43 when fixing the Bus window and resonant cavity 2; therefore, placing the third-stage sealing gaskets 42 on the screws 43 eliminates the gap at the perforation. These three seals ensure the seal between the incident end 20 and the first Bus window 30, and also ensure the seal between the exit end 21 and the second Bus window 31.

[0028] Please see Figures 1 to 9 The device also includes a laser, which is located on one side of the incident end 20 of the resonant cavity 2. The laser emitted from the laser is reflected by a first reflecting mirror 51 and a second reflecting mirror 52 to the first Busch window 30. Both the first reflecting mirror 51 and the second reflecting mirror 52 are inclined at 45° to ensure that the laser emitted from the laser is parallel to the laser incident on the first Busch window 30. In this embodiment, placing the laser on one side and sending the laser to the resonant cavity 2 through two reflecting mirrors reduces the size of the device, making the structure more compact. The laser is fixedly connected to the collimator 50 via a flange joint. The collimator 50 has a built-in collimating lens to collimate the laser emitted from the laser.

[0029] Please see Figures 1 to 9The incident end 20 of the resonant cavity 2 is provided with an incident high reflector 22, and the exit end 21 of the resonant cavity 2 is provided with an exit high reflector 23. In the embodiment, the high reflectors are arranged at the incident end 20 and the exit end 21, and the high reflector with 99.99% reflectivity can be selected. Preferably, the incident high reflector 22 and the exit high reflector 23 are fixed in the resonant cavity 2 through a mirror frame 24. The high reflector is fixed through the mirror frame 24, so that the stability of the high reflector can be ensured.

[0030] Please refer to Figures 1 to 9 The exit end 21 of the resonant cavity 2 is further provided with a focusing lens 25. In the embodiment, the focusing lens 25 is arranged at the exit end 21, so that the light beam can be focused into a minimum spot, and the light spot is incident on the photodetector 53. Therefore, the energy of the light detected by the photodetector 53 is maximized, and the sensitivity of the detection is improved.

[0031] So far, the working principle of the device is the same as that of the existing device for detecting the concentration of gas by using the optical cavity ring-down spectroscopy technology. The wavelength laser (near-infrared) corresponding to the measured gas is used to measure the ring-down time of the laser in the resonant cavity 2, so as to obtain the decay rate and then obtain the concentration of the gas. In the process, the photodetector 53 is used to convert the optical signal into an electrical signal. The working principle is the prior art, and will not be described here. The sealing property of the resonant cavity 2 is improved in the embodiment, so that the reliability and detection accuracy of the device are very high.

[0032] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the utility model, and the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A gas concentration detection device comprising a base and a resonant cavity provided on the base, characterized in that: The first and second Brewster windows are respectively fixed on the incident end and the emission end of the resonant cavity.

2. The gas concentration detecting device according to claim 1, wherein: The multi-stage sealing structure comprises a first-stage sealing gasket clamped between the first Brewster window and the incident end and between the second Brewster window and the emission end.

3. A gas concentration detecting device according to claim 2, wherein: The first-stage sealing gasket has a ring structure.

4. The gas concentration detecting device according to claim 1, wherein: The first-stage sealing gasket is provided with a plurality of perforations, and the perforations are uniformly and sequentially arranged along the circumferential direction of the first-stage sealing gasket.

5. The gas concentration detecting device according to claim 1, wherein: The multi-stage sealing structure comprises a second-stage sealing ring embedded in the annular groove of the resonant cavity.

6. The gas concentration detecting device according to claim 1, wherein: The multi-stage sealing structure comprises a third-stage sealing washer, and the first and second Brewster windows are each provided with a plurality of screw holes.

7. A gas concentration detecting device as claimed in claim 6, characterized in that: The first and second Brewster windows are fixed by screws inserted into the screw holes.

8. The gas concentration detecting device according to claim 1, wherein: The laser is arranged on one side of the incident end of the resonant cavity.

9. A gas concentration detecting device as claimed in claim 8, characterized in that: The laser emitted by the laser is reflected to the first Brewster window through a first reflector and a second reflector.

10. The gas concentration detecting device according to claim 1, wherein: The first and second reflectors are each arranged at an angle of 45° to make the laser emitted by the laser parallel to the laser incident on the first Brewster window. The incident end of the resonant cavity is provided with an incident high-reflectivity mirror, and the emission end of the resonant cavity is provided with an emission high-reflectivity mirror. The incident and emission high-reflectivity mirrors are fixed in the resonant cavity by a mirror holder. The emission end of the resonant cavity is further provided with a focusing lens.

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