CN110646363B

CN110646363B - Infrared gas sensor

Info

Publication number: CN110646363B
Application number: CN201810670505.7A
Authority: CN
Inventors: 万霞; 黄隆重; 尹斌; 黄宁杰; 其他发明人请求不公开姓名
Original assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Current assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Priority date: 2018-06-26
Filing date: 2018-06-26
Publication date: 2021-11-26
Anticipated expiration: 2038-06-26
Also published as: CN110646363A

Abstract

The invention discloses an infrared gas sensor which comprises a shell, an infrared light source and an infrared detector, wherein the shell is provided with a through hole and comprises a first shell and a second shell which are connected with each other, the first shell is provided with a first cavity communicated with the through hole, and the inner surface of the side wall of the first shell is provided with a reflecting surface; the second shell is connected with the first shell, the second shell is provided with a first channel and a second channel which are arranged at intervals, the first channel and the second channel are communicated with the first cavity, the infrared light source is arranged in the first channel, the infrared detector is arranged in the second channel, and the plane where the light path in the first channel and the light path in the second channel is located and the plane where the light path in which the infrared light is reflected by the reflecting surface in sequence are perpendicular to each other. The infrared gas sensor of the invention can reduce the volume of the infrared gas sensor.

Description

Infrared gas sensor

Technical Field

The invention relates to the technical field of gas detection, in particular to an infrared gas sensor.

Background

The infrared gas sensor is a gas sensing device which selects absorption characteristics based on near infrared spectra of different gas molecules, identifies gas components by utilizing the relation between gas concentration and absorption intensity and determines the concentration of the gas components. The infrared gas sensor includes an infrared light source, an infrared detector, and an optical gas cell that confines infrared light therein. After the infrared light absorbs the gas to be detected, the light intensity of the infrared light is weakened, so that the infrared detector is adopted to detect the light intensity change of the infrared light, and the concentration of the gas to be detected is obtained.

However, existing infrared gas sensors are bulky and there is a need for improvement.

Disclosure of Invention

The invention provides an infrared gas sensor which can reduce the size of the infrared gas sensor.

The infrared gas sensor according to the embodiment of the invention comprises a shell, an infrared light source and an infrared detector, wherein the shell is provided with a through hole, and the shell comprises: the first shell is provided with a first cavity communicated with the through hole, and the inner surface of the side wall of the first shell is provided with a first reflecting surface, a second reflecting surface, a third reflecting surface and a fourth reflecting surface; the second shell is connected with the first shell, the second shell is provided with a first channel and a second channel which are arranged at intervals, the first channel is communicated with the first cavity, the second channel is communicated with the first cavity, the infrared light source is arranged in the first channel, the infrared detector is arranged in the second channel, infrared light emitted by the infrared light source is transmitted to the first reflecting surface along the first channel and is reflected to the fourth reflecting surface sequentially through the first reflecting surface, the second reflecting surface and the third reflecting surface, the infrared light incident on the fourth reflecting surface is reflected by the fourth reflecting surface and is transmitted to the infrared detector along the second channel, and the plane where the light path of the infrared light in the first channel and the light path in the second channel are positioned is a first plane, the plane where the light path of the infrared light reflected to the fourth reflecting surface sequentially through the first reflecting surface, the second reflecting surface and the third reflecting surface is a second plane, and the second plane is perpendicular to the first plane.

According to the infrared gas sensor provided by the embodiment of the invention, infrared light is transmitted in two planes which are perpendicular to each other, the space of the infrared gas sensor is fully utilized, the light beam transmission with a large optical path can be realized in a smaller space, and the size of the infrared gas sensor can be reduced.

In some embodiments, the side wall of the first housing includes a first side wall, a second side wall, a third side wall, a fourth side wall, a fifth side wall and a sixth side wall which are connected in sequence and enclose the first chamber, an inner surface of the first side wall is inclined outward by 45 ° in a direction toward the second housing, the second side wall and the sixth side wall are parallel to each other, the third side wall and the fifth side wall are inclined by 45 ° with respect to the fourth side wall and an included angle between the third side wall and the fifth side wall is 90 °, the first reflective surface and the fourth reflective surface are provided on an inner surface of the first side wall and spaced apart from each other, the second reflective surface is provided on an inner surface of the third side wall, and the third reflective surface is provided on an inner surface of the fifth side wall.

In some embodiments, the axial directions of the first and second channels are parallel.

In some embodiments, the second housing is provided at a bottom of the first housing, and the first channel and the second channel each extend downward from an upper surface of a top wall of the second housing and to the bottom of the second housing.

In some embodiments, the infrared gas sensor further includes a circuit board, the bottom of the second housing is open, the circuit board is disposed at the bottom of the second housing, and the infrared light source and the infrared detector are both disposed on an upper surface of the circuit board.

In some embodiments, the second housing has a second chamber communicating with the first chamber, the through hole is provided in the second housing, the through hole includes a first through hole communicating with the second chamber and a second through hole communicating with the second chamber and the first chamber.

In some embodiments, the side wall of the second housing includes a second left side wall and a second right side wall spaced apart from the second left side wall, the first through hole is provided in the second left side wall and the second right side wall, a partition is provided in the second chamber, the partition divides the second chamber into a second left chamber and a second right chamber, the first through hole in the second left side wall communicates with the second left chamber, and the first through hole in the second right side wall communicates with the second right chamber.

In some embodiments, the infrared gas sensor further comprises a reflector cup nested within the first channel and abutting an inner surface of the first channel, the infrared light source being disposed within the reflector cup.

In some embodiments, the reflector cup includes a cylindrical section and a parabolic section connected to an upper end of the cylindrical section, the first channel includes a first section, a second section and a third section which are connected in sequence from bottom to top, an outer circumferential profile of the cylindrical section is adapted to an inner circumferential profile of the first section, an inner circumferential profile of the parabolic section is adapted to an inner circumferential profile of the second section, and an inner diameter of the third section is consistent along an axial direction of the first channel.

In some embodiments, an inner surface of the sidewall of the first case is plated with a gold thin film to form the first, second, third, and fourth reflective surfaces.

Drawings

Fig. 1 is an overall structural view of an infrared gas sensor according to an embodiment of the present invention.

Fig. 2 is an exploded view of an infrared gas sensor according to an embodiment of the present invention.

Fig. 3 is a bottom view of a first housing of an infrared gas sensor in accordance with an embodiment of the present invention.

Fig. 4 is a structural view of the infrared gas sensor according to an embodiment of the present invention with the bottom of the first housing facing upward.

Fig. 5 is a structural view of a second housing of the infrared gas sensor according to the embodiment of the invention.

Fig. 6 is a cross-sectional view of a second housing of an infrared gas sensor according to an embodiment of the invention.

Fig. 7-9 are schematic diagrams of infrared light transmission of an infrared gas sensor according to embodiments of the invention.

Reference numerals:

the infrared detector comprises a housing 1, a first housing 11, a first chamber 110, a first side wall 111, a second side wall 112, a third side wall 113, a fourth side wall 114, a fifth side wall 115, a sixth side wall 116, a second housing 12, a second chamber 120, a first channel 121, a first section 1211, a second section 1212, a third section 1213, a second channel 122, a second left side wall 123, a second right side wall 124, an infrared light source 2, an infrared detector 3, a through hole 4, a first through hole 41, a second through hole 42, a first reflecting surface 5, a second reflecting surface 6, a third reflecting surface 7, a fourth reflecting surface 8, a circuit board 9, a reflective cup 10, a cylindrical section 101, and a parabolic section 102.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention. In the description of the present invention, it is to be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.

As shown in fig. 1 to 9, an infrared gas sensor according to an embodiment of the present invention includes a housing 1, an infrared light source 2, and an infrared detector 3, and the housing 1 is provided with a through hole 4. In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate.

The housing 1 includes a first housing 11 and a second housing 12. In the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

As shown in fig. 2, 3 and 4, the first housing 11 has a first chamber 110, the first chamber 110 is communicated with the through hole 4, and the gas to be measured can enter the first chamber 110 through the through hole 4. The inner surface of the sidewall of the first housing 11 is provided with a first reflecting surface 5, a second reflecting surface 6, a third reflecting surface 7 and a fourth reflecting surface 8, that is, the sidewall surface enclosing the first chamber 110 is provided with the first reflecting surface 5, the second reflecting surface 6, the third reflecting surface 7 and the fourth reflecting surface 8. As shown in fig. 1, 2 and 5, the second housing 12 is connected to the first housing 11, the second housing 12 is provided with a first channel 121 and a second channel 122 arranged at intervals, the first channel 121 is communicated with the first chamber 110, the second channel 122 is communicated with the first chamber 110, the infrared light source 2 is arranged in the first channel 121, the infrared detector 3 is arranged in the second channel 122, wherein infrared light emitted by the infrared light source 2 is transmitted to the first reflecting surface 5 along the first channel 121 and is reflected to the fourth reflecting surface 8 through the first reflecting surface 5, the second reflecting surface 6 and the third reflecting surface 7 in sequence, infrared light incident on the fourth reflecting surface 8 is reflected by the fourth reflecting surface 8 and is transmitted to the infrared detector 3 along the second channel 122, a plane where an optical path of the infrared light in the first channel 121 and an optical path of the infrared light in the second channel 122 are located is a first plane, it can be understood that the transmission of the infrared light in the first plane is limited to the first channel 121 and the second channel 121, the reception rate of the light beam can be improved. The plane where the optical path of the infrared light reflected to the fourth reflecting surface 8 by the first reflecting surface 5, the second reflecting surface 6 and the third reflecting surface 7 in sequence is a second plane, and the second plane is perpendicular to the first plane.

In other words, the transmission path of the infrared light is that the infrared light of the infrared light source 2 is transmitted to the first reflection surface 5 along the first channel 121 and is reflected to the second reflection surface 6 by the first reflection surface 5 (as shown in fig. 7), the infrared light incident to the second reflection surface 6 is reflected to the third reflection surface 7 by the second reflection surface 6, the infrared light incident to the third reflection surface 7 is reflected to the fourth reflection surface 8 by the third reflection surface 7 (as shown in fig. 8), the infrared light incident to the fourth reflection surface 8 is reflected by the fourth reflection surface 8 and is transmitted to the infrared detector 3 along the second channel 122 (as shown in fig. 9), the plane where the infrared light is transmitted in the first channel 121 and the second channel 122 is perpendicular to the plane where the infrared light is reflected by the first reflecting surface 5, the second reflecting surface 6, the third reflecting surface 7 and the fourth reflecting surface 8 in sequence, that is, the infrared light is transmitted in two planes.

Specifically, the material of the housing 1 is brass, aluminum alloy, plastic, glass, or the like. The infrared light source 2 may be infrared light generated by heating and emitting light from a filament, or may be an infrared LED light source, and it should be understood that the arrangement form of the infrared light source 2 is not limited thereto. The infrared detector 3 is a pyroelectric infrared detector, a thermopile infrared detector, a pyroelectric infrared detector, or the like, wherein a detection channel of the infrared detector 3 can be a single channel to detect a single gas, and can also be a multi-channel to detect a plurality of gases.

In some embodiments, as shown in fig. 3 and 4, the side walls of the first housing 11 include a first side wall 111, a second side wall 112, a third side wall 113, a fourth side wall 114, a fifth side wall 115, and a sixth side wall 116 connected in sequence and enclosing the first chamber 110, an inner surface of the first side wall 111 is inclined outward by 45 ° in a direction toward the second housing 12, the second side wall 112 and the sixth side wall 116 are parallel to each other, the third side wall 113 and the fifth side wall 115 are inclined by 45 ° relative to the fourth side wall 114, an included angle between the third side wall 113 and the fifth side wall 115 is 90 °, the first reflective surface 5 and the fourth reflective surface 8 are disposed on the inner surface of the first side wall 111 and spaced apart from each other, the second reflective surface 6 is disposed on the inner surface of the third side wall 113, and the third reflective surface 7 is disposed on the inner surface of the fifth side wall 115. Here, the direction towards the first chamber 110 is defined as inward, and the direction away from the first chamber 110 is defined as outward.

In other words, the outer peripheral contour of the cross section of the first housing 11 is substantially hexagonal, the first chamber 110 of the first housing 11 is surrounded by a first side wall 111, a second side wall 112, a third side wall 113, a fourth side wall 114, a fifth side wall 115 and a sixth side wall 116, the second side wall 112 and the sixth side wall 116 are arranged parallel to and spaced from each other, the inner surface of the first side wall 111 is inclined 45 ° from the inside to the outside in the direction from the first housing 11 to the second housing 12, the third side wall 113 and the fifth side wall 115 are inclined 45 ° with respect to the fourth side wall 114, and the included angle between the third side wall 113 and the fifth side wall 115 is 90 °, wherein the first reflecting surface 5 and the fourth reflecting surface 8 are arranged on the inner surface of the first side wall 111 and spaced from each other, i.e. the first reflecting surface 5 and the fourth reflecting surface 8 are both inclined 45 ° from the inside to the outside in the direction from the first housing 11 to the second housing 12, so that the first reflecting surface 5 receives the infrared light in the first channel 121 and reflects to the second reflecting surface 6, the light incident on the fourth reflecting surface 8 is reflected to the infrared detector 3 along the second channel 122; the second reflecting surface 6 is disposed on the inner surface of the third sidewall 113, and the third reflecting surface 7 is disposed on the inner surface of the fifth sidewall 115, that is, the second reflecting surface 6 and the third reflecting surface 7 are inclined 45 ° with respect to the fourth sidewall 114, and the included angle between the second reflecting surface 6 and the third reflecting surface 7 is 90 °, so that the light incident on the first reflecting surface 5 is reflected on the fourth reflecting surface 8 through the second reflecting surface 6 and the third reflecting surface 8 in sequence.

Specifically, the fourth sidewall 114 is perpendicular to the second sidewall 112 and also perpendicular to the sixth sidewall 116, the length of the fourth sidewall 114 is smaller than the distance between the second sidewall 112 and the sixth sidewall 116, the angle between the inner surface of the fourth sidewall 114 and the inner surface of the third sidewall 113 is 135 °, and the angle between the inner surface of the fourth sidewall 114 and the inner surface of the fifth sidewall 115 is 135 °.

More specifically, the inner surface of the first sidewall 111 includes a first inner surface and a second inner surface, the first inner surface and the second inner surface are spaced apart from each other, the first inner surface is located inside the second inner surface, the first reflecting surface 5 is provided on the first inner surface, and the fourth reflecting surface 8 is provided on the second inner surface, that is, the first reflecting surface 5 is located inside the fourth reflecting surface 8.

In some embodiments, as shown in fig. 5, the axial directions of the first and

second channels

121 and 122 are parallel. It will be appreciated that the axial parallelism of the first channel 121 and the second channel 122 is within the tolerances permitted in the art.

In some embodiments, the second housing 12 is disposed at the bottom of the first housing 11, and the first channel 121 and the second channel 122 both extend downward from the upper surface of the top wall of the second housing 12 and to the bottom of the second housing 12. In other words, the first housing 11 and the second housing 12 are sequentially disposed in the top-to-bottom direction and connected to each other, and the first channel 121 and the second channel 122 each extend downward from the upper surface of the second housing 12 and extend to the bottom of the second housing 12.

In some embodiments, as shown in fig. 2, 5 and 6, the infrared gas sensor further includes a circuit board 9, the bottom of the second housing 12 is open, that is, the bottom of the second housing 12 is open, the circuit board 9 is disposed at the bottom of the second housing 12, and the infrared light source 2 and the infrared detector 3 are both disposed on the upper surface of the circuit board 9. In other words, the infrared light source 2 is disposed on the upper surface of the circuit board 9 and located at the bottom end of the first channel 121, and the infrared detector 3 is disposed on the lower surface of the circuit board 9 and located at the bottom end of the second channel 122.

Specifically, the circuit board 9 is provided with a signal processing circuit, and the signal processing circuit can obtain a real-time data value of the infrared detector 3, and perform filtering, amplification, temperature compensation and digital-to-analog conversion on a voltage signal generated by the infrared detector 3. The signal processing circuit can also modulate the infrared light source 2 in a pulse mode to make the infrared light source 2 emit light periodically.

In some embodiments, the second housing 12 has a second chamber 120 communicating with the first chamber 110, the through hole 4 is disposed in the second housing 12, the through hole 4 includes a first through hole 41 and a second through hole 42, the first through hole 41 communicates with the second chamber 120, the second through hole 42 communicates with the second chamber 120 and the first chamber 110, so that the gas to be measured enters the second chamber 120 through the first through hole 41, and the gas in the second chamber 120 enters the first chamber 110 through the second through hole 42.

It can be understood that, by arranging the through hole 4 in the second housing 12 to allow the gas to enter the first chamber 110 of the first housing 11 through the second chamber 120 of the second housing 12, and not arranging the through hole communicated with the first chamber 110 on the first housing 11, it is possible to reduce the leakage of the infrared light during the transmission process, improve the utilization rate of the light source and the acceptance rate of the infrared detector, and thus improve the detection efficiency.

Specifically, the first through hole 41 is provided in the side wall of the second housing 12, so that the gas to be measured is provided on the top wall of the second housing 12 through the second through hole 42 in the side wall. Further, the first through holes 41 and the second through holes 42 are provided in plural, in other words, the side wall of the second housing 12 is provided with the first through holes 41, and the top wall of the second housing 12 is provided with the second through holes 42, so as to improve the air intake efficiency. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In some embodiments, as shown in fig. 2 and 5, the side walls of the second housing 12 include a second left side wall 123 and a second right side wall 124, the second right side wall 124 and the second left side wall 123 are spaced apart from each other, and the first through hole 41 is disposed on the second left side wall 123 and the second right side wall 124, in other words, the first through hole 41 is disposed on both the second left side wall 123 and the second right side wall 124, specifically, the plurality of first through holes 41 are disposed on the second left side wall 123, and the plurality of first through holes 41 are also disposed on the second right side wall 124.

A partition plate is arranged in the second chamber 120, the partition plate divides the second chamber 120 into a second left chamber and a second right chamber, the first through hole 41 in the second left side wall 123 is communicated with the second left chamber, and the first through hole 41 in the second right side wall 124 is communicated with the second right chamber. It can be understood that, by dividing the second chamber 120 by the partition, the gas entering the second chamber 120 from the first through hole 41 of the second left sidewall 123 can be prevented from leaking out of the first through hole 41 of the second right sidewall 124, and the gas entering the second chamber 120 from the first through hole 41 of the second right sidewall 124 can be prevented from leaking out of the first through hole 41 of the second left sidewall 123, so that the gas to be measured can be prevented from entering the first chamber 110 from the second chamber 120.

In some embodiments, as shown in fig. 6, the infrared gas sensor further comprises a reflector cup 10, the reflector cup 10 is nested in the first channel 121 and abuts against the inner surface of the first channel 121, and the infrared light source 3 is disposed in the reflector cup 10. Specifically, the reflector cup 10 nests in the bottom end of the first channel 121. The reflector cup is one of the reflecting devices, and the reflecting device is used for controlling the illumination distance and the illumination area of the main light spot through a light reflector in order to utilize limited light energy.

In some alternative embodiments, the reflector cup 10 includes a cylindrical section 101 and a parabolic section 102, and the parabolic section 102 is connected to the upper end of the cylindrical section 101, specifically, the inner diameter of the cylindrical section 101 is consistent along the axial direction of the first passage 121, that is, the inner diameter of the cylindrical section 101 is kept constant along the axial direction of the first passage 121.

The first channel 121 comprises a first section 1211, a second section 1212 and a third section 1213 which are connected in sequence from bottom to top, wherein the outer peripheral profile of the cylindrical section 101 is matched with the inner peripheral profile of the first section 1211, the inner peripheral profile of the parabolic section 102 is matched with the inner peripheral profile of the second section 1212, and the inner diameter of the third section 1213 is constant along the axial direction of the first channel 121, i.e. the inner diameter of the third section 1213 is kept constant along the axial direction of the first channel 121.

The reflector cup 10 with the above structure is suitable for an infrared light source generated by heating and emitting light of a filament with a certain height, and the structure can be beneficial to arranging the light emitting surface of the filament on the focal plane of the parabolic reflecting surface of the parabolic section 102. It will be appreciated that the construction of the reflector cup 10 is not so limited, for example in alternative embodiments the reflector cup 10 is formed as a parabolic reflector throughout. The reflective cup 10 with the structure is suitable for a thinner infrared LED light source.

In some embodiments, the inner surface of the sidewall of the first housing 11 is plated with a gold thin film to form the first, second, third, and fourth

reflective surfaces

5, 6, 7, and 8. In other words, the reflecting surface is formed by plating a gold film on the inner surface of the sidewall of the first housing 11, and specifically, the gold film is plated on the inner surface of the sidewall of the first housing 11 after polishing, which is beneficial to the total reflection of light, reduces loss, and also avoids material oxidation.

An infrared gas sensor according to an embodiment of the present invention is described below with reference to fig. 1 to 9.

As shown in fig. 1 to 9, an infrared gas sensor according to an embodiment of the present invention includes a housing 1, an infrared light source 2, an infrared detector 3, a circuit board 9, and a reflective cup 10, where the housing 1 is made of brass, aluminum alloy, plastic, glass, or the like, and the infrared light source 2 may be infrared light generated by heating a filament to emit light. The infrared detector 3 is a pyroelectric infrared detector, a thermopile infrared detector, a pyroelectric infrared detector, or the like, wherein a detection channel of the infrared detector 3 can be a single channel to detect a single gas, and can also be a multi-channel to detect a plurality of gases.

The longitudinal direction of the housing 1 is defined as the left-right direction, the width direction of the housing 1 is defined as the front-rear direction, the height direction of the housing 1 is defined as the up-down direction, and the direction toward the inside of the housing 1 is defined as the inside and the direction toward the outside of the housing 1 is defined as the outside.

The housing 1 includes a first housing 11 and a second housing 12 which are arranged in sequence from top to bottom and connected to each other, the first housing 11 has a first chamber 110, the side walls of the first housing 11 include a first side wall 111, a second side wall 112, a third side wall 113, a fourth side wall 114, a fifth side wall 115 and a sixth side wall 116 which enclose the first chamber 110, wherein the first side wall 111 and the fourth side wall 114 extend in a left-right direction, the second side wall 112 and the sixth side wall 113 extend in a front-back direction and are spaced apart from each other in the left-right direction, the length of the fourth side wall 114 in the left-right direction is smaller than the distance between the second side wall 112 and the sixth side wall 113, and the included angle between each of the third side wall 113 and the fifth side wall 115 and the fourth side wall 114 is 135 °.

The inner surface of the first sidewall 111 includes a first inner surface and a second inner surface, both of which are inclined from inside to outside by 45 ° in a top-to-bottom direction, and the first inner surface and the second inner surface are spaced apart from each other, the first inner surface being located inside the second inner surface, and the inner surfaces of the second sidewall 112, the third sidewall 113, the fourth sidewall 114, the fifth sidewall 115, and the sixth sidewall 116 are flat surfaces that are flat in the top-to-bottom direction, wherein the first inner surface of the first sidewall 111 is provided with a first reflection surface 5, the second inner surface of the first sidewall 111 is provided with a fourth reflection surface 8, the inner surface of the third sidewall 113 is provided with a second reflection surface 6, and the inner surface of the fifth sidewall 115 is provided with a third reflection surface 7. The first reflecting surface 5, the second reflecting surface 6, the third reflecting surface 7 and the fourth reflecting surface 8 are formed by polishing the inner surface of the side wall of the first shell 11 and then plating a gold film.

The second housing 12 has a second chamber 120, the second housing 12 is provided with a first channel 121 and a second channel 122 spaced apart from each other, the axial directions of the first channel 121 and the second channel 122 are parallel, and the first channel 121 and the second channel 122 each extend downward from the upper surface of the top wall of the second housing 12 and to the bottom of the second housing 12. The second housing 12 is provided with a through hole 4 for the gas to be measured to enter, and the through hole 4 includes a first through hole 41 communicated with the second chamber 120 and a second through hole 42 communicated with the second chamber 120 and the first chamber 110. The side walls of the second housing 12 include a second left side wall 123 and a second right side wall 124 spaced apart from each other in the left-right direction, the first through holes 41 are provided on the second left side wall 123 and the second right side wall 124, and the second left side wall 123 and the second right side wall 124 are each provided with a plurality of first through holes 41, and the second through holes 42 are provided on the top wall of the second housing 12 to communicate the second chamber 120 with the first chamber 110. A partition plate is arranged in the second chamber 120, the partition plate divides the second chamber 120 into a second left chamber and a second right chamber, the first through hole 41 in the second left side wall 123 is communicated with the second left chamber, and the first through hole 41 in the second right side wall 124 is communicated with the second right chamber.

The bottom of second casing 12 is uncovered to be set up and circuit board 9 establishes in the bottom of second casing 12, and infrared light source 2 and infrared detector 3 all establish the upper surface at circuit board 9, and infrared light source 2 is located the bottom in first passageway 121, and infrared detector 3 is located the bottom in second passageway 122. The circuit board 9 is provided with a signal processing circuit, and the signal processing circuit can obtain a real-time data value of the infrared detector 3 and perform filtering, amplification, temperature compensation and digital-to-analog conversion on a voltage signal generated by the infrared detector 3. The signal processing circuit can also modulate the infrared light source 2 in a pulse mode to make the infrared light source 2 emit light periodically.

The reflecting cup 10 is nested at the bottom end in the first channel 121 and is abutted against the inner surface of the first channel 121, the infrared light source 3 is arranged in the reflecting cup 10, the reflecting cup 10 comprises a cylindrical section 101 and a parabolic section 102, the parabolic section 102 is connected with the upper end of the cylindrical section 101, and the inner diameter of the cylindrical section 101 is kept constant along the axial direction of the first channel 121. The first channel 121 comprises a first section 1211, a second section 1212 and a third section 1213 which are connected in sequence from bottom to top, wherein the outer peripheral profile of the cylindrical section 101 is matched with the inner peripheral profile of the first section 1211, the inner peripheral profile of the parabolic section 102 is matched with the inner peripheral profile of the second section 1212, and the inner diameter of the third section 1213 is kept constant along the axial direction of the first channel 121.

Wherein the transmission path of the infrared light is that the infrared light of the infrared light source 2 is transmitted to the first reflection surface 5 along the first channel 121 and is reflected to the second reflection surface 6 by the first reflection surface 5, the infrared light incident to the second reflection surface 6 is reflected to the third reflection surface 7 by the second reflection surface 6, the infrared light incident to the third reflection surface 7 is reflected to the fourth reflection surface 8 by the third reflection surface 7, the infrared light incident to the fourth reflection surface 8 is reflected by the fourth reflection surface 8 and is transmitted to the infrared detector 3 along the second channel 122, wherein the transmission of the infrared light in the first channel 121 and the second channel 122 is in a vertical plane in which the vertical direction and the left-right direction are located, the transmission of the infrared light reflected by the first reflection surface 5, the second reflection surface 6, the third reflection surface 7 and the fourth reflection surface 8 in sequence is in a horizontal plane in which the front-back direction and the left-right direction are located, that is to say, the infrared light is transmitted in two planes, namely a vertical plane and a horizontal plane, in the infrared gas sensor, the space of the infrared gas sensor is fully utilized, and the large-optical-path light beam transmission in a smaller space can be realized, so that the size of the infrared gas sensor can be reduced.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. The utility model provides an infrared gas sensor, its characterized in that, includes casing, infrared light source and infrared detector, be equipped with the through-hole on the casing, the casing includes:

the first shell is provided with a first cavity communicated with the through hole, and the inner surface of the side wall of the first shell is provided with a first reflecting surface, a second reflecting surface, a third reflecting surface and a fourth reflecting surface;

the second shell is connected with the first shell, the second shell is provided with a first channel and a second channel which are arranged at intervals, the first channel is communicated with the first cavity, the second channel is communicated with the first cavity, the infrared light source is arranged in the first channel, the infrared detector is arranged in the second channel, infrared light emitted by the infrared light source is transmitted to the first reflecting surface along the first channel and is reflected to the fourth reflecting surface sequentially through the first reflecting surface, the second reflecting surface and the third reflecting surface, the infrared light incident on the fourth reflecting surface is reflected by the fourth reflecting surface and is transmitted to the infrared detector along the second channel, and the plane where the light path of the infrared light in the first channel and the light path in the second channel are positioned is a first plane, the plane where the light path of the infrared light reflected to the fourth reflecting surface by the first reflecting surface, the second reflecting surface and the third reflecting surface in sequence is a second plane, and the second plane is perpendicular to the first plane;

the second shell is provided with a second cavity communicated with the first cavity, the through hole is formed in the second shell and comprises a first through hole and a second through hole, the first through hole is communicated with the second cavity, and the second through hole is communicated with the second cavity and the first cavity;

the first shell is not provided with a through hole which is communicated with the first cavity and the outside of the infrared gas sensor.

2. The infrared gas sensor according to claim 1, wherein the side wall of the first housing includes a first side wall, a second side wall, a third side wall, a fourth side wall, a fifth side wall and a sixth side wall which are connected in sequence and enclose the first chamber, an inner surface of the first side wall is inclined 45 ° outward in a direction toward the second housing, the second side wall and the sixth side wall are parallel to each other, the third side wall and the fifth side wall are inclined 45 ° with respect to the fourth side wall and an included angle between the third side wall and the fifth side wall is 90 °, the first reflective surface and the fourth reflective surface are provided on the inner surface of the first side wall and are spaced apart from each other, the second reflective surface is provided on the inner surface of the third side wall, and the third reflective surface is provided on the inner surface of the fifth side wall.

3. The infrared gas sensor as set forth in claim 1 wherein the axial directions of the first channel and the second channel are parallel.

4. The infrared gas sensor as set forth in claim 1, wherein the second housing is provided at a bottom of the first housing, and the first channel and the second channel each extend downward from an upper surface of a top wall of the second housing and to the bottom of the second housing.

5. The infrared gas sensor as recited in claim 4, further comprising a circuit board, wherein the bottom of the second housing is open, the circuit board is disposed at the bottom of the second housing, and the infrared light source and the infrared detector are disposed on an upper surface of the circuit board.

6. The infrared gas sensor as recited in claim 1, wherein the side walls of the second housing include a second left side wall and a second right side wall spaced apart from the second left side wall, the first through hole is provided in the second left side wall and the second right side wall, a partition is provided in the second chamber, the partition divides the second chamber into a second left chamber and a second right chamber, the first through hole in the second left side wall communicates with the second left chamber, and the first through hole in the second right side wall communicates with the second right chamber.

7. The infrared gas sensor as claimed in any one of claims 1 to 6, further comprising a reflector cup nested within the first channel and abutting an inner surface of the first channel, the infrared light source being disposed within the reflector cup.

8. The infrared gas sensor as recited in claim 7, wherein the reflector cup includes a cylindrical section and a parabolic section connected to an upper end of the cylindrical section, the first channel includes a first section, a second section and a third section that are sequentially connected from bottom to top, an outer circumferential profile of the cylindrical section is adapted to an inner circumferential profile of the first section, an inner circumferential profile of the parabolic section is adapted to an inner circumferential profile of the second section, and an inner diameter of the third section is uniform along an axial direction of the first channel.

9. The infrared gas sensor as claimed in any one of claims 1 to 6, wherein an inner surface of the side wall of the first case is plated with a gold thin film to form the first, second, third and fourth reflecting surfaces.