KR20100135060A - Optical gas sensor and gas concentration analyzer including the same - Google Patents

Abstract

PURPOSE: A light gas sensor and a gas concentration analyzer including the same are provided to improve detection sensitivity with respect to target gases by collecting light from light source. CONSTITUTION: A light gas sensor includes a light cavity(40), light source(20), a detection part(60), and a reflection part(80). The light cavity includes a gas inlet(44) and a gas outlet(46). The light source radiates light by being arranged at one side of the light cavity. The detection part is spaced apart from the light source. The reflection part is arranged between the light source and the detection part. The reflection part guides light from the light source to the detection part.

Description

OPTICAL GAS SENSOR AND GAS CONCENTRATION ANALYZER INCLUDING THE SAME}

The present invention relates to an optical sensor and a gas concentration analysis apparatus using the same, and more particularly, to an optical gas sensor using an optical principle having an improved detection structure for increasing a plurality of gas detection capabilities, and a gas concentration using the same. It relates to an analysis device.

Generally, the gas concentration analyzer detects carbon dioxide (CO ₂ ), carbon monoxide (CO), or methane gas (CH ₄ ) in the atmosphere, and the gas concentration analyzer is classified into a contact type and a non-contact type. Non-contact method of gas concentration analyzer of low cost optical gas sensor method using optical principle mainly uses non-dispersive infrared (NDIR) sensor (hereinafter referred to as NDIR). do.

The NDIR gas sensor method uses a physical sensing principle in which a target gas is absorbed by a specific wavelength, and has high selectivity and sensitivity. The NDIR gas sensor is generally reflected by the light path several times and absorbed by the measurement gas present in the optical cavity, and the remaining amount of light absorbed is reduced in intensity compared to the initial amount of light ( The principle by which light intensity is measured is used.

On the other hand, in the case of the NDIR gas sensor system, the sensitivity is excellent when the amount of light irradiated from the light source reaches the detection unit without loss in addition to being absorbed by the gas. Therefore, a technical configuration for condensing the amount of light emitted from the light source to the detection unit is required.

In addition, instead of detecting one target target gas using the NDIR gas sensor method, it is efficient to set a plurality of target target gases to detect the plurality of target target gases. Therefore, a technique suitable for setting a plurality of target target gases and detecting a plurality of target gases is required.

Accordingly, an object of the present invention is to provide an optical gas sensor and a gas concentration analyzing apparatus using the same, which can improve the detection sensitivity for a gas to be detected by concentrating the amount of light emitted from the light source.

Another object of the present invention is to provide an optical gas sensor capable of detecting a plurality of target gases and improving productivity according to the detection, and a gas concentration analyzing apparatus using the same.

According to the present invention, there are provided an optical cavity in which a gas inlet and a gas outlet are provided, a light source disposed at one side of the optical cavity and irradiating light, and the other side of the optical cavity. A detector disposed spaced from the light source and having a plurality of detection sensors, and a reflector arranged at a predetermined angle and a radius of curvature between the light source and the detector to guide light emitted from the light source to the detector; The reflector is bent at a predetermined angle with respect to the center axis of the plurality of detection sensor separation distance according to the separation distance of the plurality of detection sensors by the optical gas sensor, characterized in that for guiding light to each detection sensor Is done.

Here, the light source may include an infrared lamp.

In addition, the reflecting unit may be formed with a plurality of reflecting surfaces corresponding to the plurality of detection sensors.

The radius of curvature may include a first radius of curvature corresponding to a focal length of the reflective surface and the detection sensor, and a second radius of curvature corresponding to a distance D between the reflective surface and the detection unit.

Preferably, the focal length of the reflective surface and the detection sensor may be proportional to the first radius of curvature.

The distance D between the reflective surface and the detection unit may be proportional to the second radius of curvature.

In addition, the gas inlet may further include a heating means for heating the gas flowing into the inlet.

On the other hand, according to the present invention, the problem solving means is based on the optical gas sensor of the above-described configuration, an output unit for outputting the gas concentration detected from the optical gas sensor, and based on the detection signal from the optical gas sensor It is also made by a gas concentration analysis device comprising a control unit for controlling the output unit.

Here, the output unit may include at least one of a display unit for displaying the detected gas concentration and a voice signal unit for notifying the voice.

Therefore, according to the above solution, the output voltage of each detection sensor can be amplified by bending the reflector to have a constant angle and radius of curvature and adjusting the focal length so that light is focused on each detection sensor. Provided are an optical gas sensor and a gas concentration analyzing apparatus including the same, which can improve detection reliability of a product.

In addition, since the heating means can be arranged in the gas inlet area to increase the diffusion rate of the gas, there is provided an optical gas sensor and a gas concentration analysis apparatus including the same that can improve the detection performance.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, only the embodiments are to make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs It is provided to fully inform the person having the scope of the invention and is only defined by the scope of the claims of the present invention.

Hereinafter, an optical gas sensor and a gas concentration analyzing apparatus including the same according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid unnecessarily obscuring the subject matter of the present invention.

Prior to the description, a preferred embodiment of the present invention will be described separately by the first embodiment including a heater as a heating means and the second embodiment including a pump. However, in the first and second preferred embodiments of the present invention, the same configuration uses the same reference numerals.

As shown in FIG. 1, the gas concentration analyzer 1 according to the present invention includes an input unit 3, a substrate 5, a non-dispersive infrared (NDIR) sensor 10, an output unit 100, and a control unit ( 160).

The input unit 3 constitutes an infrared lamp driving driver circuit for applying an operation signal to the NDIR gas sensor 10, and various detection target gas types such as carbon dioxide (CO ₂ ) or methane gas (CH ₄ ) are applied by the application signal. Can be measured. Since the gas concentration analysis apparatus 1 according to the present invention can detect two gases, it measures two gas concentration values in real time.

The substrate 5 serves as an electrical medium for the electronic components (not shown) for supplying power from the outside to the NDIR gas sensor 10 and the like and the NDIR gas sensor 10. In an embodiment of the present invention, electronic components are mounted on a plate of the substrate 5, and a plurality of intake portions 7 are formed to penetrate the gas into the NDIR gas sensor 10. The substrate 5 is provided with heating means to be described later according to the first embodiment of the present invention in the plurality of intake portions 7. Detailed description of the heating means will be described later.

Next, as illustrated in FIGS. 2 to 4, the NDIR gas sensor 10 of the present invention includes a light source 20, an optical cavity 40, a detector 60, a reflector 80, and heating means.

The light source 20 uses an infrared lamp. Since the light source 20 used as the infrared lamp has an infrared wavelength of about 1 to 10 μm, it is more widely used than a diode or a laser diode emitting only one wavelength when measuring a plurality of gases. Can be. Therefore, using an infrared lamp having a wide range of wavelengths as the light source 20 is suitable for the NDIR gas sensor 10 for measuring a plurality of gases.

The optical cavity 40 receives the light source 20, the detector 60, and the reflector 80 as one embodiment of the present invention. However, unlike the present invention, it may also include heating means. The optical cavity 40 of the present invention includes an optical cavity body 42, a gas inlet 44 and a gas outlet 46.

The optical cavity body 42 forms an optical path 48 of infrared light emitted from the light source 20 accommodated on one side of the interior. As an embodiment of the present invention, the optical cavity 42 may be provided in a cylindrical shape, and may have various polygonal cross-sectional shapes in addition to the cylindrical shape, unlike the present invention. However, in consideration of characteristics of light such as reflection of infrared light emitted from the light source 20, the optical cavity body 42 is preferably provided in a cylindrical shape as in the present invention.

The gas inlet 44 and the gas outlet 46 are formed in the optical cavity main body 42 with a spaced apart distance from each other. The gas inlet 44 and the gas outlet 46 are opened in mutually opposite directions, as shown in FIGS. Here, the gas inlet 44 communicates with the intake portion 7 of the substrate 5. In other words, the gas introduced through the intake unit 7 flows into the optical cavity main body 42 via the gas inlet 44.

The detection unit 60 includes an detection unit body 62, a filter 64, a detection sensor 66, and a connection unit 68 as an embodiment of the present invention. The detection unit 60 is accommodated inside the optical cavity main body 42 and is spaced apart from the light source 20 in the horizontal direction of the infrared irradiation direction to detect the amount of light irradiated to the optical path 48.

5 and 6, the detection unit 60 is an embodiment of the present invention. The detection unit 60 is spaced apart from the light source 20 disposed on one side of the optical cavity main body 42, so that the detection unit 60 is located within the optical cavity main body 42. It is arranged on the other side. The detection unit 60 is disposed adjacent to the substrate 5 in a horizontal direction in the infrared irradiation direction irradiated from the light source 20, that is, lower than the arrangement position of the light source 20. Here, the detection unit 60 is disposed downward in the horizontal direction with respect to the infrared irradiation direction irradiated from the light source 20 as an embodiment of the present invention, but is disposed upward in accordance with the structure change of the reflector 80 to be described later There may be.

The detection unit body 62 forms the appearance of the detection unit 60 and accommodates the detection sensor 66. In addition, a filter 64 is disposed on one side of the detection unit body 62, and a connecting portion 68 electrically connected to the substrate 5 is disposed on the other side thereof.

The filter 64 serves to filter gases other than the set detection target. For example, if the target detection target gas is carbon dioxide (CO ₂ ), since it absorbs the most infrared rays at 4.26 μm, a gas other than carbon dioxide (CO ₂ ) is used by using a filter 64 that transmits only a wavelength of 4.26 μm. To filter them.

The filter 64 of the present invention is provided in plurality in correspondence with the first reflecting portion 82 and the second reflecting portion 84 to be described later. The filter 64 includes a first filter 64a and a second filter 64b corresponding to the first reflecting portion 82 and the second reflecting portion 94, respectively. Here, the first filter 64a and the second filter 64b are provided so that different detection target gases are respectively filtered.

For example described gritty, the first filter (64a) is detected in the gas NDIR gas sensor 10, a carbon dioxide (CO ₂₎ one time using a filter 64 for transmitting only 4.26um, except for carbon dioxide (CO ₂₎ Other gases are filtered out. On the other hand, when the detection target gas of the NDIR gas sensor 10 is methane gas (CH ₄ ), the second filter 64b filters other gases except methane gas by using a filter 64 that transmits only 3.31 um. As such, the first filter 64a and the second filter 64b filter different gases from each other, so that the NDIR gas sensor 10 of the present invention can detect two gases. Of course, if the number of filters 64, the corresponding detection sensor 66, etc. increases, the detection target gas may also increase.

The detection sensor 66 is provided with a first detection sensor 66a and a second detection sensor 66b corresponding to the number of filters 64. The detection sensor 66 detects the amount of infrared light that has passed the filtering, and transmits the detected signal to the controller 160. The interaction between the detection sensor 66 and the control unit 160 is performed by component elements of the detection unit 60 (not shown). In general, since the detection sensor 66 is smaller than the cross-sectional area of the filter 64, it is preferable that light is collected more.

Next, the reflector 80 is disposed between the light source 20 and the detector 60 at a predetermined angle and a radius of curvature, and guides the light emitted from the light source 20 to the detector 60. Here, the reflector 80 is inclined at an angle of 45 degrees with the infrared irradiation direction irradiated from the light source 20 as an embodiment of the present invention. Since the reflector 80 forms an angle of 45 degrees with the infrared irradiation direction, the infrared rays reflected by the reflector 80 are guided at an angle of 90 degrees with the infrared irradiation direction.

On the other hand, the reflector 80 of the present invention is inclined from the upper surface to the lower surface of the optical cavity main body 42 to guide the infrared ray to the detection unit 60 disposed downward with respect to the infrared irradiation direction. However, the reflection unit 80 may be inclined from the lower surface of the optical cavity main body 42 to the upper surface when the detection unit 60 is disposed upward with respect to the infrared irradiation direction.

In addition, the reflector 80 of the present invention has a predetermined angle with respect to the center axis of the plurality of detection sensors 66 according to the separation distance of the plurality of detection sensors 66 as in the embodiment of the present invention. It is bent to guide light to each detection sensor 66. The reflector 80 is bent based on the center axis of the detection sensor 66 and is divided into a first reflector 82 and a second reflector 84, and the first reflector 82 and the second reflector. The unit 84 has two reflection surfaces corresponding to the two detection sensors 66. That is, the reflective surface is formed corresponding to the number of detection sensors 66 disposed in the detection unit 60.

의 각도로 절곡된다. 여기서,

은 검출센서(66)의 상호 이격거리 중심축선과 90도의 각도를 이루므로 반사부(80)는 판상으로 마련된다.Referring to FIG. 6, when the mutual separation distance of the detection sensor 66 on the right side is 'd', the left side (a) indicates that the infrared rays reflected by the reflector 80 are separated from the detection sensor 66. On the basis of the center distance of the separation distance of the detection sensor 66 to correspond to the separation distance

Is bent at an angle. here,

Is an angle of 90 degrees with the central axis of the mutual separation distance of the detection sensor 66, the reflecting portion 80 is provided in a plate shape.

의 각도로 절곡된다.

는 검출센서 이격거리의 중심축선에 대해

의 각도보다 작은 각도로 절곡된다.On the other hand, (b) detects when 'd' of (a) is changed to the separation distance of 'd', that is, when the separation distance between the detection sensors 66 is greater than the separation distance 'd' of (a). With respect to the center line of the separation distance of the sensor 66

Is bent at an angle.

Is the center axis of the sensor

It is bent at an angle smaller than the angle of.

의 각도로 절곡된다.

는 검출센서 이격거리의 중심축선에 대해

의 각도보다 큰 각도로 절곡되고, 이에 따라 반사부(80)에 의해 반사된 초점거리가 변경된다.And, (c) is based on the separation axis center axis of the detection sensor 66 when 'd' of (a) is changed to the separation distance of 'd'

Is bent at an angle.

Is the center axis of the sensor

It is bent at an angle greater than the angle of, and thus the focal length reflected by the reflector 80 is changed.

Referring to (a), (b) and (c) described above, when the sensor sensor 66 is disposed at an angle of 90 degrees with respect to the center axis of the separation distance, the mutual separation distance of the detection sensor 66 is referenced. When is small, the reflector 80 is bent toward the light source 20 on the basis of the central axis. On the other hand, when the mutual separation distance of the detection sensor 66 increases, it can be seen that the reflector 80 is bent in the opposite direction of the light source 20 on the basis of the central axis.

Therefore, the reflector 80 may be bent based on the center axis of the detection sensor 66 according to the separation distance of the detection sensor 66 to guide the infrared rays to each detection sensor 66.

However, the reflecting surface of the reflecting unit 80 has a radius of curvature such that the infrared rays irradiated from the light source 20 are guided to the detecting unit 60 to be collected by the plurality of detection sensors 66. Here, the radius of curvature includes a first radius of curvature corresponding to the focal length of the reflective surface and the detection sensor 66 and a second radius of curvature corresponding to the distance D between the reflective surface and the detection unit 60. The first radius of curvature is changed according to the focal length of the reflective surface and the detection sensor 66, and the second radius of curvature is the separation distance D between the reflective surface and the detection unit 60, where the separation distance is substantially the reflective surface and the detection unit. The focal length of 60).

For example, referring to FIGS. 5 and 6, the first radius of curvature represents a degree of warp with respect to the 'z-axis'. Therefore, the first radius of curvature is (a), (b) and (c) the shorter the focal length between the reflective surface and the detection sensor 66 in the (a), (b) and the first curvature radius becomes smaller so that the curvature of the reflective surface is larger, and vice versa When the focal length between the slope and the detection sensor 66 is longer, the first radius of curvature is increased so that the curvature of the reflective surface is smaller. That is, the focal length of the reflective surface and the detection sensor 66 is proportional to the first radius of curvature.

On the other hand, the second radius of curvature represents the degree of warp with respect to the 'y-axis' differently from the first radius of curvature so as to correspond to the distance D between the reflective surface and the detection unit 60. Here, the second radius of curvature is related to the curvature of the reflecting surface in contact with the tangent line forming an inclination of 45 degrees with the irradiation direction of the infrared rays. That is, the second radius of curvature is provided so that the infrared rays reflected on the reflective surface are guided to the detector 60, unlike the first radius of curvature for condensing infrared rays by the detection sensor 66.

The second radius of curvature becomes larger as the distance D between the second reflecting surface and the detector 60 becomes longer, and becomes smaller as the distance D between the reflective surface and the detector 60 becomes smaller. Of course, the first radius of curvature is proportional to the separation distance D between the reflective surface and the detection unit 60.

Therefore, by changing the first radius of curvature and the second radius of curvature of the reflecting surface, the infrared rays irradiated from the light source 20 are condensed by the respective detection sensors 66 to improve the detection reliability.

Next, the heating means is provided to heat the gas flowing into the gas inlet. The heating means of the first embodiment of the present invention includes a heater (90). Of course, the heating means may be used in addition to the heater 90, such as heat generating parts that can generate heat.

The heater 90 is disposed adjacent to the intake portion 7 region on the substrate 5 to heat the gas flowing through the intake portion 7 to increase the diffusion rate of the gas. The diffusion speed of the gas flowing into the optical cavity 40 is increased by the mounting of the heater 90, thereby improving the response time detected by the NDIR gas sensor 10. The heater 90 of the present invention is turned on or off based on a signal from the heater driving unit 182 operated by the control of the controller 160 to be described later. However, unlike the present invention, the operating time of the heater 90 can be adjusted according to the atmospheric circulation performance.

Here, the heating means described in the first embodiment of the present invention is described as being disposed on the substrate 5, but may be disposed in the gas inlet 44 region of the NDIR gas sensor 10.

The output unit 100 outputs the gas concentration detected from the NDIR gas sensor 10. The output unit 100 includes a display unit 120 for displaying the detected gas concentration, and a voice signal unit 140 for notifying a voice signal. Although the output unit 100 of the present invention includes the display unit 120 and the voice signal unit 140, the display unit 120 and the voice signal unit 140 may include only one.

The controller 160 controls the output unit 100 to output the detected signal to the output unit 100 based on the signal detected by the NDIR gas sensor 10. The controller 160 controls the output of the small voltage proportional to the amount of light detected by the NDIR gas sensor 10 to be outputted to the output unit 100. Here, the output value output by the control of the controller 160 is represented by the gas concentration.

On the other hand, as shown in Figure 7, the gas concentration analysis device 1 according to the second embodiment of the present invention further includes a pump 200 in addition to the configuration of the first embodiment of the present invention. However, the gas concentration analysis apparatus 1 according to the second embodiment of the present invention is an absorption type, and unlike the first embodiment of the present invention, no heating means is included. The absorption gas concentration analyzer 1 circulates the gas flowing in and out of the optical cavity 40 by using the pump 200, so that heating means for increasing the diffusion rate of the gas is unnecessary.

Looking at the operation of the gas concentration analysis device 1 according to the present invention by such a configuration as follows.

The operation process of the gas concentration analysis apparatus 1 according to the first and second embodiments of the present invention is only a configuration including a heater 90 and a pump 200, respectively, the other configuration NDIR gas sensor 10, etc. Since it is the same, only the first embodiment will be described.

First, an operation signal of the gas concentration analyzer 1 is applied to the input unit 3. Then, the light source 20 of the NDIR gas sensor 10 is activated and the infrared light is irradiated from the light source 20 accordingly.

Atmospheric gas flows through the intake portion 7. At this time, the diffusion speed of the gas flowing through the intake portion 7 is increased by the heater 90 disposed in the intake portion 7 region. The gas thus raised flows into the optical cavity main body 42 through the gas inlet 44, and the gas flowing into the optical cavity main body 42 flows out through the gas outlet 46.

The gas flowing in the optical cavity main body 42 absorbs the infrared rays irradiated from the light source 20. In addition, the infrared rays are reflected by the reflector 80 and are guided to the detector 60 disposed downward in the infrared irradiation direction. Here, the reflecting surface of the reflector 80 is formed with a predetermined angle and a radius of curvature toward the light source 20, and the infrared rays reflected by the reflector 80 are guided to the detector 60.

The reflector 80 is bent based on the center axis of the two detection sensors 66 and is divided into a first reflector 82 and a second reflector 84, and the first reflector 82 and Infrared is guided to each detection sensor 66 by two reflecting surfaces formed on the second reflecting portion 84. The reflective surface is guided by infrared rays by a first radius of curvature corresponding to a focal length with the detection sensor 66 and a second radius of curvature corresponding to a separation distance D with the detection unit 60 to detect each of the detection sensors 66. Is condensed into. The first radius of curvature and the second radius of curvature prevent the infrared light from being focused on only one axis.

The infrared rays guided to the detection unit 60 pass through the filter 64 to reach the detection sensor 66. The detection sensor 66 transmits the detected detection signal to the controller 160. The controller 160 controls the output unit 100 to output the gas concentration based on the detection signal transmitted from the detection sensor 66. Here, the output unit 100 informs the gas concentration detected by the graphic and voice signals using the display unit 120 and the voice signal unit 140. Here, the leaked gas is blocked when the gas leaked by a gas circuit breaker not shown in the present invention.

Accordingly, the reflector is bent to have a predetermined angle and radius of curvature so as to correspond to the distance between the reflector and the detector and the separation distance between the reflector and the detection sensor. The voltage can be improved, and thus the detection reliability of the product can be improved.

In addition, since the heating means may be disposed in the gas inflow area, the diffusion speed of the gas may be increased, thereby improving the response time.

1 is a control block diagram of a gas concentration analysis apparatus according to the present invention,

2 is a schematic perspective view of a NDIR gas sensor according to the present invention;

3 is a cross-sectional view taken along line III-III of the NDIR gas sensor shown in FIG. 2;

4 is a cross-sectional view taken along line IV-IV of the NDIR gas sensor shown in FIG. 2;

FIG. 5 is a perspective view illustrating main parts of the NDIR gas sensor shown in FIG. 2; FIG.

6 is a perspective view of a detector and a reflector of the NDIR gas sensor according to the present invention;

7 is a schematic diagram illustrating a pump included in the NDIR gas sensor of FIG. 1.

<Description of the symbols for the main parts of the drawings>

 1: Gas concentration analysis device 10: NDIR gas sensor

20: light source 40: optical cavity

44: gas inlet 46: gas outlet

48: optical path 60: detector

64: filter 66: detection sensor

80: reflecting portion 82: first reflecting portion

84: second reflector 90: heater

Claims (9)

Optical cavity with gas inlet and gas outlet: A light source disposed at one side of the optical cavity and radiating light; A detector disposed at the other side of the optical cavity with respect to the light source and having a plurality of detection sensors; It is disposed between the light source and the detector having a predetermined angle and a radius of curvature, and includes a reflector for guiding the light emitted from the light source to the detector, The reflector is bent at a predetermined angle with respect to the center axis of the plurality of detection sensor separation distance according to the separation distance of the plurality of detection sensors, the optical gas sensor, characterized in that to guide the light to each detection sensor . The method of claim 1, The light source is an optical gas sensor, characterized in that it comprises an infrared lamp. The method of claim 1, The reflector is an optical gas sensor, characterized in that a plurality of reflecting surfaces are formed corresponding to the plurality of detection sensors. The method of claim 3, The radius of curvature is, A first radius of curvature corresponding to a focal length of the reflective surface and the detection sensor; And a second radius of curvature corresponding to the distance D between the reflective surface and the detection unit. The method of claim 4, wherein And a focal length of the reflective surface and the detection sensor is proportional to the first radius of curvature. The method of claim 4, wherein The distance D between the reflective surface and the detector is in proportion to the second radius of curvature. The method of claim 1, Gas concentration analysis device further comprises a heating means for heating the gas flowing into the gas inlet. The optical gas sensor of any one of claims 1 to 7, An output unit for outputting a gas concentration detected from the optical gas sensor; And a control unit for controlling the output unit based on the detection signal from the optical gas sensor. The method of claim 8, The output unit gas concentration analysis device comprising at least one of a display unit for displaying the detected gas concentration and a voice signal unit to inform the voice.

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