CN212159554U

CN212159554U - Gas detection device based on NDIR principle

Info

Publication number: CN212159554U
Application number: CN202020715616.8U
Authority: CN
Inventors: 王相; 田聪聪; 杨开华; 庞喜龙
Original assignee: Weihai Jingxun Changtong Electronic Technology Co Ltd
Current assignee: Weihai Jingxun Changtong Electronic Technology Co Ltd
Priority date: 2020-04-30
Filing date: 2020-04-30
Publication date: 2020-12-15
Anticipated expiration: 2030-04-30

Abstract

The application provides a gas detection device based on an NDIR principle, which relates to the technical field of gas concentration detection and comprises a bottom plate and a detection shell which is buckled with the bottom plate, wherein a mounting seat is fixed on the bottom plate; one end of the mounting seat is a light source transmitting end, and the other end of the mounting seat is a light source receiving end; the inside of detecting the casing is equipped with the light path cavity, the light path cavity adopts plastics material, the internal surface of light path cavity adopts electroplated metal polishing to handle. The application is designed based on the NDIR principle, the change path of light in the gas detection cavity is analyzed based on the mathematical model, the corner radian of the cavity is determined based on the change path, the plastic model is made, and electroplating is carried out on the plastic model, so that the reflection effect of the cavity is increased, and the manufacturing cost is reduced.

Description

Gas detection device based on NDIR principle

Technical Field

The application relates to the technical field of gas concentration detection, in particular to a gas detection device based on an NDIR principle.

Background

NDIR (Non-dispersive infra-red sensor) infrared gas sensors use a broad-spectrum light source IR Lamp as the light source of the infrared sensor, and light passes through the gas to be detected in the light path cavity, passes through the narrow-band filter and reaches the infrared detector. The working principle of the gas sensing device is that the absorption characteristics are selected based on the near infrared spectra of different gas molecules, and the gas components are identified and the concentration of the gas components is determined by utilizing the relation (Lambert-Beer law) between the gas concentration and the absorption intensity.

The detection mode is to indirectly obtain the concentration of the gas by detecting the loss of light with specific wavelength. The more the loss of light is reduced, the more accurate the measurement results are. Therefore, the cavity with good reflection effect can enable more light to be absorbed by the gas, the loss of the light is reduced, and the detection precision is higher.

The patent with application number 201921098738.0 discloses a carbon dioxide detection device, and the material in the cavity is plastics in this patent, and the casing inner chamber surface is level and smooth circular-arc, and this patent though can reduce the loss of light, the circular arc structure of this kind of optional form, the die sinking is more random, can not reach best optical reflection effect, and the die sinking is more random moreover, and good cavity reflection effect also can not be realized to the plastics material. In order to improve the reflection effect, a metal material is adopted as a light reflecting material in the prior art, so that although the light reflection effect is improved, the cost is increased.

SUMMERY OF THE UTILITY MODEL

To the problem that exists among the prior art, this application provides a gaseous detection device based on NDIR principle, has analyzed the change route of light in gaseous detection cavity based on mathematical model, has confirmed the cavity corner radian based on this, does the plastics model to electroplate on the plastics model, in order to reach the reflectance that improves gaseous detection device cavity, reduce the beneficial effect of cost simultaneously.

The application provides a gas detection device based on an NDIR principle, which comprises a bottom plate and a detection shell, wherein the detection shell is buckled with the bottom plate; one end of the mounting seat is a light source transmitting end, and the other end of the mounting seat is a light source receiving end; the inside of detecting the casing is equipped with the light path cavity, the light path cavity adopts plastics material, the internal surface of light path cavity adopts electroplated metal polishing to handle.

Further, the light path cavity adopts a linear cavity.

Further, the light path cavity adopts a spiral cavity.

Furthermore, the inner side surface of the detection shell close to one side of the light source receiving end is an arc-shaped inner cavity surface, and the arc-shaped inner cavity surface is concave towards one side far away from the light source emitting end.

Furthermore, the arc-shaped inner cavity surface is composed of a plurality of plane units, the included angle between the plane units is 0.1-0.4 degrees, and light emitted by the arc-shaped inner cavity surface is focused on a light source receiving end.

Further, the inner cavity of the light path cavity is a cylindrical cavity or a cuboid cavity.

Furthermore, a spiral pipeline is arranged inside the detection shell, the inner surface of the spiral pipeline is smooth and circular-arc-shaped, and a cavity defined by the spiral pipeline is a spiral cavity.

Furthermore, the included angle between the plurality of plane units is 0.4 degrees.

Further, the inner surface of the light path cavity is subjected to water electroplating metal polishing treatment; and before the hydroelectric plating metal polishing treatment, a copper-nickel alloy is adopted for bottoming.

Further, the light source emitting end adopts a point light source.

The beneficial effect of this application lies in:

1. the application provides a gaseous detection device based on NDIR principle, the internal surface of detection casing forms the light path cavity, the light path cavity adopts the plastics material, the internal surface of light path cavity adopts the electro-plating metal polishing to handle, does the plastics model, and the die sinking is simple to electroplate on the plastics model, reduced the cost of manufacture, increased the reflection effect of cavity.

2. In this application the light path cavity adopts sharp die cavity, the medial surface that detects the casing and be close to 5 one sides of light source receiving terminal is the arc inner chamber face, and the light path cavity that this application provided designs based on the NDIR principle, has analyzed the change route of light in gaseous detection cavity based on mathematical model, has confirmed cavity corner radian based on this to increase the reflection effect of cavity.

3. In the application, the arc inner cavity surface is composed of a plurality of plane units, the included angle between the plane units is 0.1-0.4 degree, and light emitted by the arc inner cavity surface is focused on the light source receiving end. By establishing a calculus mathematical model, an arc type of a gathering receiving point is approximately formed by a tiny end of a value according to a tangential direction vector, and the mathematical model is utilized to finely adjust a focus and a reflective area, so that each point of light reflection tends to focus on a set photosensitive area, and a good light receiving effect is achieved. And (3) performing an optical analysis simulation experiment on the detection cavity by using Zemax optical Stidio, wherein the received light obtained by analysis accounts for more than 85%, and the loss light source does not exceed 5%.

4. The application provides a spiral cavity light path through the continuous reflection of circular shape light path cavity in total vortex line route, can guarantee like this that the black body effect that right angle or oblique angle caused light can not appear, reduces the loss of light, can make through the design of this kind of light path in addition prolong the optical path in limited space environment, improve and detect the precision. In addition, because the spiral cavity does not generate an angle, light can be finally received by the light source receiving end. In order to enable the cavity to achieve the reflection effect of the metal material, electroplating polishing treatment is carried out on the plastic cavity.

5. In order to improve the reflection degree of light, an electroplating process of water electroplating is adopted, the plating layer of the water electroplating has simple process and low cost, and compared with spray powder vacuum plating which needs complicated equipment and process and has high requirements, the plating layer is neat, corners can be uniformly attached, the thickness of the plating layer is basically consistent, the phenomenon of vacuum degree material accumulation cannot occur, and the reflection degree is better.

6. In order to improve the adhesion capability of the electroplated metal, the copper-nickel alloy is firstly used for priming and then the metal is electroplated during electroplating.

In addition, the design principle of the application is reliable, the structure is simple, and the application prospect is very wide.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a front view schematically illustrating a gas detecting apparatus according to an embodiment of the present invention.

Fig. 2 is a schematic top view of a gas detection device according to an embodiment of the present disclosure.

FIG. 3 is a schematic axial view of a gas detection device according to an embodiment of the present application.

FIG. 4 is a schematic view of the ray path of a straight cavity in one embodiment of the present application.

FIG. 5 is a schematic view of the light path of the spiral cavity in one embodiment of the present application.

In the figure, the device comprises a base plate 1, a base plate 2, a detection shell 3, light rays 4, a light source emitting end 5, a light source receiving end 6, a spiral pipeline 7 and an arc-shaped inner cavity surface.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The following explains key terms appearing in the present application.

As shown in fig. 1-3, the present application provides a gas detection device based on NDIR principle, which includes a bottom plate 1 and a detection housing 2 fastened to each other, where the bottom plate 1 is a circuit board. The bottom plate 1 is provided with a positioning hole, the detection shell 2 is provided with a mounting hole matched with the positioning hole, a locking bolt is arranged in the mounting hole, and the locking bolt penetrates through the mounting hole and the corresponding positioning hole to fixedly mount the detection shell 2 on the bottom plate 1.

The mounting seat is fixed on the bottom plate 1 and fixedly connected with the bottom plate 1. One end on the mounting seat is a light source transmitting end 4, the other end is a light source receiving end 5, and the light source receiving end 5 is mounted on the circuit board and is integrated with the circuit board. In this embodiment, the light source emitting end 4 is a point light source. An infrared detector is arranged at the light source receiving end 5 and can absorb light with specific wavelength. The inner surface of the detection shell 2 forms a light path cavity.

The inside of detecting casing 2 is equipped with the light path cavity, the light path cavity adopts the plastics material, the internal surface of light path cavity adopts electroplated metal polishing to handle. The material that forms the light path cavity in this application adopts the plastics model preparation to form, and the die sinking is simple to electroplate on the plastics model, reduced the cost of manufacture, increased the reflection effect of cavity.

In the first embodiment, the optical path cavity adopts a linear cavity, specifically, the inner cavity of the optical path cavity adopts a cylindrical cavity, and in other embodiments, the inner cavity of the optical path cavity also can adopt a cuboid cavity.

In the first embodiment, as shown in fig. 4, an inner side surface of the detection housing 2 close to the light source receiving end 5 is an arc-shaped inner cavity surface 7, and the arc-shaped inner cavity surface 7 is concave towards a side far away from the light source emitting end 4. Specifically, the arc-shaped inner cavity surface 7 is composed of a plurality of plane units, and an included angle between the plane units is 0.4 degree.

In other embodiments, the included angle between the planar units may also be any angle between 0.1 and 0.4, and the light reflected by the planar units can be focused on the photosensitive area at the receiving end of the light source.

In the actual detection process, light 3 emitted from a light source emitting end 4 is emitted into a linear cavity, and is focused on an arc-shaped inner cavity surface 7 after being reflected for multiple times by the inner side wall of the cavity, the light 3 is reflected by the arc-shaped inner cavity surface 7, so that the focus after being reflected by the light source is concentrated in a photosensitive area at a light source receiving end 5, an arc type of a concentrated receiving point is approximately formed by a small end of a value according to a tangential direction vector by establishing a calculus mathematical model, and the focus and a reflective area are finely adjusted by the mathematical model, so that each point of light reflection tends to be focused on the set photosensitive area, and a good light receiving effect is achieved. And (4) describing an arc formed by the analysis of the mathematical model as an edge arc of the gas detection cavity. In the embodiment, a Zemax optical Stidio is used for carrying out an optical analysis simulation experiment on the detection cavity, the received light obtained by analysis accounts for more than 85%, and the loss of the light source is not more than 5%.

In the second embodiment, as shown in fig. 5, a spiral duct 6 is provided inside the detection housing 2, the inner surface of the spiral duct 6 is smooth and arc-shaped, and the cavity surrounded by the spiral duct 6 is a spiral cavity. In this embodiment, through the continuous reflection of circular shape light path cavity in total vortex line route, can guarantee like this that the black body effect that right angle or oblique angle caused light can not appear, reduce the loss of light, can make the route of light reach the longest in limited space environment through the design of this kind of light path in addition, prolong the optical path, improve and detect the precision.

Because the light path cavity adopts the spiral cavity, and an angle is generated in the spiral cavity, the whole light can be finally received by the light source receiving end, and the detection precision is improved.

The spiral pipeline 6 and the detection shell 2 are made of plastic materials, the cavity made of plastic materials is produced according to a determined cavity model, the mold opening is simple, water and electricity plating polishing treatment is carried out on the inner surface of the plastic cavity in order to enable the cavity to achieve the reflection effect of the metal materials, light loss is reduced, and meanwhile cost is reduced.

Considering that the plated part plated by the plastic part is easy to float, the part contacted with the hanger is easy to be burnt, and the plastic part is easy to float in the solution because of small specific gravity, so the electroplating process of water electroplating is more suitable compared with the vacuum degree. And the plating layer of water electroplating is simple in process and low in cost, compared with spray powder vacuum plating which needs complicated equipment and process and high requirements, the plating layer is neat, edges and corners can be uniformly attached, the thickness of the plating layer is basically consistent, the phenomenon of vacuum degree material accumulation cannot occur, and the light reflecting degree is better.

In order to improve the adhesion capability of the electroplated metal, the copper-nickel alloy is firstly used for priming and then the metal is electroplated during electroplating. The proportion of the copper-nickel alloy and the metal is 0.1% -0.3%, for example, 15 microns of copper-nickel alloy is used as a bottom layer to improve the adhesion capability of gold, and 0.015-0.045 microns of electroplated metal is arranged on a surface layer, so that the cost is reduced and a good reflection effect is achieved.

The application provides a gaseous detection device based on NDIR principle, the internal surface of detection casing forms the light path cavity, the light path cavity adopts sharp die cavity or spiral die cavity. The application provides a light path cavity designs based on the NDIR principle, has analyzed the change route of light in gaseous detection cavity based on mathematical model, has confirmed the cavity corner radian based on this, makes the plastic model to electroplate on the plastic model, with the reflection effect who increases the cavity.

Although the present application has been described in detail with reference to the accompanying drawings in conjunction with the preferred embodiments, the present application is not limited thereto. Various equivalent modifications or substitutions can be made on the embodiments of the present application by those skilled in the art without departing from the spirit and scope of the present application, and these modifications or substitutions are intended to be covered by the present application/any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A gas detection device based on NDIR principle, its characterized in that: the device comprises a bottom plate (1) and a detection shell (2) which is buckled with the bottom plate, wherein a mounting seat is fixed on the bottom plate (1); one end of the mounting seat is a light source emitting end (4), and the other end of the mounting seat is a light source receiving end (5); the inside of detecting casing (2) is equipped with the light path cavity, the light path cavity adopts the plastics material, the internal surface of light path cavity adopts the polishing of electroplated metal to handle.

2. The NDIR principle based gas sensing device of claim 1, wherein: the light path cavity adopts a linear cavity.

3. The NDIR principle based gas sensing device of claim 1, wherein: the light path cavity adopts a spiral cavity.

4. The NDIR principle based gas sensing device of claim 2, wherein: the inner side surface of one side, close to the light source receiving end (5), of the detection shell (2) is an arc-shaped inner cavity surface (7), and the arc-shaped inner cavity surface (7) is concave towards one side far away from the light source emitting end (4).

5. The NDIR principle based gas sensing device of claim 4, wherein: the arc-shaped inner cavity surface (7) is composed of a plurality of plane units, the included angle between the plane units is 0.1-0.4 degrees, and light emitted by the arc-shaped inner cavity surface (7) is focused on the light source receiving end (5).

6. The NDIR principle based gas sensing device of claim 2, wherein: the inner cavity of the light path cavity is a cylindrical cavity or a cuboid cavity.

7. A gas detecting device based on NDIR principle according to claim 3, characterized in that: the inside of detecting casing (2) is equipped with helical piping (6), and the internal surface of helical piping (6) is smooth circular-arc, the cavity that helical piping (6) enclose is the spiral die cavity.

8. The NDIR principle based gas sensing device of claim 5, wherein: and the included angle between the plurality of plane units is 0.4 degree.

9. The NDIR principle based gas sensing device of claim 1, wherein: the inner surface of the light path cavity is subjected to water electroplating metal polishing treatment; and before the hydroelectric plating metal polishing treatment, a copper-nickel alloy is adopted for bottoming.

10. The NDIR principle based gas sensing device of claim 1, wherein: the light source emitting end (4) adopts a point light source.