CN216926569U

CN216926569U - Gas detection device

Info

Publication number: CN216926569U
Application number: CN202123185178.2U
Authority: CN
Inventors: 王琦琪; 陈焕波
Original assignee: Ningbo Sunny Infrared Technologies Co Ltd
Current assignee: Ningbo Sunny Infrared Technologies Co Ltd
Priority date: 2021-12-17
Filing date: 2021-12-17
Publication date: 2022-07-08
Anticipated expiration: 2031-12-17

Abstract

The utility model relates to a gas detection device which comprises a shell (1), an infrared light source (2) and an infrared detector (3), wherein an annular cavity (1b) is formed in the shell (1), the infrared light source (2) and the infrared detector (3) are both arranged in the annular cavity (1b), and the infrared detector (3) is a double-light-path detector and is provided with a gas channel window sheet and a reference channel window sheet which are axially arranged along the annular cavity (1b) and are both perpendicular to the annular central line of the annular cavity (1 b). The gas detection device has the characteristics of small volume, high precision, low cost, long service life and capability of meeting the intrinsic safety requirement.

Description

Gas detection device

Technical Field

The present invention relates to a gas detection device.

Background

However, methane is flammable and explosive, and is colorless and odorless, so that if leakage occurs, it is difficult to detect the leakage intuitively, and a device capable of accurately detecting the concentration of methane in the environment in real time is needed. In the prior art, methane detection is generally realized by utilizing an electrochemical catalysis principle, and the devices have the defects of easy loss, easy failure, short service life and the like, so most of the devices are replaced by detection devices (namely infrared detectors) utilizing an NDIR principle. However, NDIR detection devices also suffer from problems of being bulky, expensive, prone to misalignment, etc. and thus there is still much room for improvement.

The detection principle of the infrared detector is that the change of the gas components is judged according to the change of the infrared light intensity received by the detector, and the infrared light intensity, the concentration of the gas, the length of the optical cavity and the light intensity of the light source approximately meet the Lambert-beer law. Wherein, I₀The infrared light source is used for emitting infrared light intensity, alpha is the infrared absorption coefficient of the target gas, C is the concentration of the target gas, I is the intensity of the light received by the outer detector, and L is the length of a light path from the light source to the detector after the light is reflected by the optical cavity. Therefore, in order to increase the accuracy of the infrared gas sensor, it is an effective technical means to extend the optical path. However, the method of extending the optical path is contrary to the trend of miniaturization of various sensors. Therefore, some technologies design the light path into a curve or folded line structure, so that the light path is extended and the miniaturization requirement is met by utilizing the light reflection principle.

For example, patent CN104280357A discloses an infrared gas sensor, which is provided with an infrared light source and a detector on the wall of an optical cavity, the inner wall of the optical cavity is a cylindrical reflecting surface, forming a "C" shaped light path of the infrared gas sensor, thereby prolonging the light path. However, the working light of the patent is converged on the detector through the reflecting surface, so that more stray light is generated, and the light intensity is weakened after the light is refracted for many times. Moreover, the detector is horizontally installed in order to receive the reflected light of the reflecting surface, so that extremely high requirements are brought to the manufacturing precision and the installation precision of the reflecting surface, and the light can be refracted again before being received by the detector, so that the light intensity is weakened again, and the improvement of the detection precision is extremely not facilitated. The detector horizontally installed also occupies more space of the optical path, and therefore, the length of the optical path is not favorable to be further prolonged.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a gas detection device.

In order to achieve the above object of the present invention, the present invention provides a gas detecting device, which comprises a housing, an infrared light source and an infrared detector, wherein the housing has an annular cavity inside, the infrared light source and the infrared detector are both disposed in the annular cavity, and the infrared detector is a dual light path detector, and has a gas channel window sheet and a reference channel window sheet which are axially arranged along the annular cavity and are both perpendicular to an annular center line of the annular cavity.

According to one aspect of the utility model, the housing comprises first and second shells, and the first shell is located inside the second shell;

the outer side of the first shell and the inner side of the second shell are respectively provided with an annular groove, and the two annular grooves are combined to form the annular cavity;

one side of the second shell is also provided with an end cover.

According to one aspect of the utility model, the device further comprises a first mounting seat, wherein a first through hole is formed in the middle of the first mounting seat, and a connecting plate is arranged on one side of the first mounting seat;

the connecting plate is connected to the end cover through a bolt, and the infrared light source is arranged in the first through hole.

According to one aspect of the utility model, the device further comprises a second mounting seat, wherein a second through hole is formed in the middle of the second mounting seat, and a connecting block is arranged on one side of the second mounting seat;

the infrared detector is arranged in the second through hole;

a positioning bulge is arranged on the infrared detector, and a positioning groove corresponding to the positioning bulge is arranged on the second mounting seat;

the first shell is provided with a mounting groove, and the connecting block is connected in the mounting groove through a bolt.

According to one aspect of the utility model, the device further comprises a filter screen and a circuit board which are respectively positioned at two sides of the shell.

According to one aspect of the utility model, a waterproof plate is arranged between the filter screen and the shell, and an insulating plate is arranged between the circuit board and the shell.

According to one aspect of the utility model, the insulating plate has a cutout adapted to the mounting notch;

the side of the shell facing the filter screen is provided with a vent hole communicated with the annular cavity;

the waterproof plate is provided with a gas passing hole corresponding to the position of the vent hole, and a waterproof breathable film is arranged in the gas passing hole;

the waterproof plate is bonded on the shell through a sealant.

According to one aspect of the utility model, the humidity control plate is positioned between the waterproof plate and the shell;

the humidity control plate is provided with a containing hole, and a humidity control sheet is arranged in the containing hole;

the accommodating hole corresponds to the air passing hole in position.

According to one aspect of the utility model, the walls of the annular cavity are gold plated.

According to one aspect of the utility model, the beams of the infrared source are tangential to the circular centerline of the annular cavity.

According to one aspect of the utility model, further comprising a housing, the housing being located in the housing.

According to one aspect of the utility model, the housing has a mounting notch;

the infrared light source and the infrared detector are arranged at the mounting notch.

According to the concept of the utility model, the gas detection device which has small volume, high precision, low cost and long service life and meets the intrinsic safety requirement is provided.

According to one scheme of the utility model, the annular cavity is utilized to form the optical path channel, so that the device has a longer optical path, and meanwhile, the device has the advantage of multiple orders in light energy, so that the detection device has higher resolution precision and signal stability. Moreover, the annular structure enables the device to be small, thereby facilitating transportation and other cost-reducing operations. And the use of the NDIR detection principle can also bring higher reliability and service life, and can reduce the later-stage use cost.

Drawings

FIGS. 1, 2 and 3 are exploded views schematically showing three views of a gas detection device according to an embodiment of the present invention;

FIG. 4 is a view schematically showing an assembled state of a gas detection apparatus according to an embodiment of the present invention;

FIG. 5 schematically illustrates a combination of a housing of an embodiment of the present invention with a first view of the light source and detector;

FIG. 6 schematically shows a block diagram of a housing of an embodiment of the utility model;

FIG. 7 is a cross-sectional view schematically illustrating the combination of the housing with the light source and detector according to one embodiment of the present invention;

FIG. 8 schematically illustrates a combined state view of the housing and a second viewing angle of the light source and detector according to an embodiment of the utility model;

FIG. 9 schematically illustrates a combined view of a housing and a third viewing angle of a light source and detector according to an embodiment of the utility model;

figure 10 schematically shows a detector window slice position diagram according to an embodiment of the utility model.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the utility model, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in an orientation or positional relationship that is based on the orientation or positional relationship shown in the associated drawings, which is for convenience and simplicity of description only, and does not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, the above-described terms should not be construed as limiting the present invention.

The present invention is described in detail below with reference to the accompanying drawings and specific embodiments, which are not described in detail herein, but the present invention is not limited to the following embodiments.

Referring to fig. 1 to 4, the intrinsically safe gas sensing apparatus for sensing methane concentration by infrared spectrum absorption (NDIR) principle of the present invention includes a housing 1, an infrared light source 2, and an infrared detector 3. In the present embodiment, the housing 1 has an installation notch 1a, and an annular cavity 1b therein, and the infrared light source 2 and the infrared detector 3 are both disposed at the installation notch 1a and located at two ends of the annular cavity 1b, respectively. Therefore, the mounting structure of the light source and the detector realizes the assembly of the light source and the detector on the premise of ensuring the miniaturization, and is also beneficial to production and manufacture. Of course, in other embodiments, the installation notch 1a may not be provided, that is, the annular cavity 1b may be a complete ring, and the infrared light source 2 and the infrared detector 3 are located inside the cavity.

Referring to fig. 5 to 10, in the present invention, the cross section of the annular cavity 1b is circular, and the infrared detector 3 is a dual optical path detector. The window sheet A of the infrared detector 3 comprises a gas (methane) channel window sheet for methane measurement and a reference channel window sheet for ensuring the long-term stable work of a methane channel, and the window sheet A and the reference channel window sheet are mutually compared, so that the functions of resisting water vapor interference and resisting temperature change can be realized. The two window sheets are both perpendicular to the annular center line of the annular cavity 1b and the light beam main shaft of the infrared light source 2. And the main axis of the light beam of the infrared light source 2 is tangent to the annular central line of the annular cavity 1b, so that the central line of the window sheet A in the vertical direction can be intersected with the optical axis, and the light rays can be received. Therefore, the light path is longer by adopting the annular structure, the precision is improved, and the purpose of tangency of the light beam main shaft and the annular center line of the cavity is to avoid light intensity loss, so that the light source intensity is improved. In addition, the detector adopts the arrangement mode that the detector is vertical and intersected with the light path, so that light rays can directly irradiate the detector after being reflected by the wall of the cavity body without being reflected again, stray light and light intensity loss can be avoided, and compared with the existing detector which is horizontally arranged, the light received by the window sheet is uniform, and errors caused by uneven light can be effectively reduced.

In addition, due to the different inner and outer diameters of the annular cavity 1B (i.e. the diameters of the groove bottoms of the annular grooves B of the first shell 11 and the first shell 12), the intensity and distribution of the light emitted by the infrared light source 2 when the light propagates to the position of the infrared detector 3 in the annular cavity 1B are also different, i.e. the light intensity received at the position of the infrared detector 3 is not uniform in the horizontal direction (i.e. the radial direction of the housing 1), but is uniform in the vertical direction (i.e. the axial direction of the housing 1). According to the detection principle of the infrared detector 3, the light intensity received by the infrared detector directly influences the detection precision. In the utility model, the gas channel window sheet and the reference channel window sheet of the infrared detector 3 are axially arranged along the annular cavity 1b, so that the light intensity received by the two window sheets A of the infrared detector 3 is uniform and consistent. Furthermore, in order to extend the optical path, the section/tangent plane of the exit port of the optical path is not through the axis of the annular cavity 1b, but this way may cause the section of the exit port to be non-circular, i.e. the spot emitted from the exit port is not uniform in the horizontal direction but is (up-down) symmetrical in the vertical direction. Therefore, the two window sheets a of the infrared detector 3 are arranged in the vertical direction, so that the illumination, the light intensity and the light spot received by the two window sheets a are all the same, information and signals are consistent, and the detection and measurement accuracy is ensured. It can also be seen that the vertical arrangement of the window pieces a is particularly important for detectors with a two-channel configuration.

In the present invention, the housing 1 includes a first shell 11 and a second shell 12, both of which are annular, and the first shell 11 is located inside the second shell 12. Wherein, the outer side of the first shell 11 and the inner side of the second shell 12 are respectively provided with mutually matched annular grooves B, and the two annular grooves are combined to form an annular cavity 1B. In addition, one side of the second shell 12 is further provided with an end cover 13, which is integrated with or separated from the second shell 12, and is mainly used as a support carrier for mounting various parts and accessories. In the utility model, the annular cavity 1b is adopted to prolong the light path, so that the reflection times of light rays are increased, the light ray energy is weakened, the total signal of the infrared detector 3 is weakened, and the resolution is reduced. Therefore, the wall of the annular cavity 1b (i.e. the wall of the annular groove) in the present invention is plated with gold, so that the optical path can be increased while the energy loss caused by a large number of reflections can be reduced, thereby satisfying the performance requirements of various aspects, and the volume can be kept at a small level.

The gas detection device also comprises a first mounting seat 4 and a second mounting seat 5 which are auxiliary positioning parts of the infrared light source 2 and the infrared detector 3 respectively. Wherein, the first through hole 41 is arranged in the middle of the first mounting seat 4, and the connecting plate 42 is arranged on one side. The connecting plate 42 is bolted to the end cap 13, and the infrared light source 2 is disposed in the first through hole 41. Thus, the infrared light source 2 is installed at the port of the annular cavity 1b through the first installation seat 4. The middle of the second mounting base 5 is provided with a second through hole 51 for accommodating the infrared detector 3, one side of the second mounting base is provided with a connecting block 52, and the infrared detector 3 is arranged in the second through hole 51. The infrared detector 3 is provided with a positioning protrusion 3a, and the second mounting base 5 is provided with a positioning groove 5a matched with the positioning protrusion 3a at the edge of the second through hole 51. So for infrared detector 5's installation is reliable and stable, and the cooperation of location arch 3a and constant head tank 5a can realize that infrared detector 3 installs accurately, stably and efficiently. In the utility model, the second mounting seat 5 and the infrared detector 3 can be integrally formed or separately prepared, and the functions are not influenced. The first housing 11 is provided with a mounting groove 11a, and the connection block 52 of the second mounting seat 5 is bolted in the mounting groove 11 a. Therefore, the first mounting seat 4 and the second mounting seat 5 are arranged, so that the size error caused by assembly can be reduced, the consistency of the device is improved, and the subsequent gas calibration operation is facilitated. Meanwhile, the installation form utilizes the limited space to the maximum extent on the premise of being convenient for assembly, and the infrared light source 2 and the infrared detector 3 are both installed at the positions which are favorable for light transmission.

The gas detection device of the present invention further comprises a filter screen 6 and a circuit board 7, which are respectively located on both sides of the housing 1. A waterproof board 8 is arranged between the filter screen 6 and the shell 1, and an insulating board 9 is arranged between the (PCB) circuit board 7 and the shell 1. The insulating plate 9 has a cutout 9a adapted to the mounting notch 1 a. The filter screen 6 is a sintered steel mesh for dust prevention and ventilation. The side of the housing 1 facing the sieve 6 has a vent hole 1c (including the first shell 11 and the end cap 13) communicating with the annular chamber 1b, so that outside air can enter the annular chamber 1 b. The waterproof board 8 is provided with a vent hole 81 corresponding to the vent hole 1c, so that smooth air flow is ensured. In addition, a waterproof and breathable film is also arranged in the air passing hole 81. The waterproof board 8 is bonded to the housing 1 by a sealant. In addition, the gas detection device of the present invention further includes a housing 10, and the housing 1 is located in the housing 10. The gas detection apparatus of the present invention further comprises a humidity control plate 15 which is located between the waterproof plate 8 and the housing 1. The humidity control plate 15 is provided with a receiving hole 151, and a humidity control sheet is disposed in the receiving hole 151. Of course, the receiving hole 151 should correspond to the position of the air passing hole 81 so as to allow the external air to pass therethrough.

According to the above arrangement, each part can be powered on to operate after being assembled in a certain assembly sequence in a compliance manner, and external gas enters the device through free diffusion, firstly passes through the filter screen 6 and the waterproof breathable film to remove impurities and water vapor, and then enters the annular cavity 1b through the vent hole 1c of the shell 1. When methane exists in the gas, the light emitted from the infrared light source 2 is proportionally absorbed by the methane gas according to the concentration, so that the number of light finally reaching the infrared detector 3 is reduced, and the light intensity is weakened. In this way, the output signal of the infrared detector 3 will change, and the signal will be processed by the algorithm to generate the corresponding methane gas concentration value. And because annular cavity 1b makes light be the annular and spreads, consequently the light is longer from the path distance that infrared light source 2 jetted out and reach infrared detector 3 to the degree of being absorbed by methane is also higher, makes infrared detector 3 can export the signal difference that has the contrast nature more, and then has promoted the resolution precision.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and it is apparent to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a gas detection device, includes casing (1), infrared source (2) and infrared detector (3), casing (1) inside has annular cavity (1b), infrared source (2) with infrared detector (3) all set up in annular cavity (1b), its characterized in that, infrared detector (3) are two light path detector, have the edge annular cavity (1b) axial arrangement and all perpendicular to the gas passage window piece and the reference channel window piece of the annular center line of annular cavity (1 b).

2. The device according to claim 1, characterized in that the housing (1) comprises a first shell (11), a second shell (12), and the first shell (11) is located inside the second shell (12);

annular grooves are respectively formed in the outer side of the first shell (11) and the inner side of the second shell (12), and the two annular grooves are combined to form the annular cavity (1 b);

the second shell (12) also has an end cap (13) on one side.

3. The device according to claim 2, further comprising a first mounting seat (4), wherein a first through hole (41) is formed in the middle of the first mounting seat (4), and a connecting plate (42) is formed on one side of the first mounting seat;

the connecting plate (42) is connected to the end cover (13) through bolts, and the infrared light source (2) is arranged in the first through hole (41).

4. The device according to claim 2, further comprising a second mounting seat (5), wherein a second through hole (51) is formed in the middle of the second mounting seat (5), and a connecting block (52) is arranged on one side of the second mounting seat;

the infrared detector (3) is arranged in the second through hole (51);

a positioning bulge (3a) is arranged on the infrared detector (3), and a positioning groove (5a) corresponding to the positioning bulge (3a) is arranged on the second mounting seat (5);

the first shell (11) is provided with a mounting groove (11a), and the connecting block (52) is connected in the mounting groove (11a) through a bolt.

5. The device according to claim 1, characterized in that it further comprises a filter screen (6) and a circuit board (7), one on each side of the housing (1).

6. The device according to claim 5, characterized in that between the screen (6) and the housing (1) there is a waterproof sheet (8) and between the circuit board (7) and the housing (1) there is an insulating sheet (9).

7. The device according to claim 6, characterized in that the housing (1) has a mounting indentation (1 a);

the infrared light source (2) and the infrared detector (3) are arranged at the installation notch (1 a).

8. The device according to claim 7, characterized in that the insulating plate (9) has a cutout (9a) adapted to the mounting notch (1 a);

the side of the shell (1) facing the filter screen (6) is provided with a vent hole (1c) communicated with the annular cavity (1 b);

the waterproof plate (8) is provided with an air passing hole (81) corresponding to the position of the vent hole (1c), and a waterproof breathable film is arranged in the air passing hole (81);

the waterproof plate (8) is bonded on the shell (1) through a sealant.

9. The device according to claim 8, further comprising a humidity control plate (15) located between the flashing (8) and the housing (1);

the humidity control plate (15) is provided with an accommodating hole (151), and a humidity control sheet is arranged in the accommodating hole (151);

the accommodating hole (151) corresponds to the air passing hole (81) in position.

10. Device according to claim 1, characterized in that the walls of the annular chamber (1b) are treated with gold plating.

11. The device according to claim 1, characterized in that the beam of the infrared source (2) has a tangential circular centerline of the annular cavity (1 b).

12. The device according to claim 1, further comprising a housing (10), the housing (1) being located in the housing (10).