Gas detection equipment

Abstract

[Problem] To provide a gas detection device with which it is possible to supply gas uniformly to a plurality of sensors. [Solution] A gas detection device according to one embodiment of the present invention comprises a casing and a plurality of sensor elements. The casing has a gas introducing part that has an introducing port, a first chamber that is connected to the introducing port, a second chamber that is connected to the first chamber, a constricting part that limits the flow of gas from the first chamber to the second chamber, and a gas evacuating part that is connected to the second chamber. The plurality of sensor elements are disposed within the second chamber, and have different detection sensitivities according to gas type.

Description

[Technical field]

[0001] The present invention relates to a highly sensitive gas detection device. [Background technology]

[0002] In conventional high-sensitivity gas detection devices, it is common to arrange multiple sensor elements to identify gas molecular species, and it is also common to forcibly transport the target gas to the sensor elements using a fan or pump to make the gas flow in (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-155576 A [Patent Document 2] Utility Model Registration No. 3094415 Summary of the Invention [Problem to be solved by the invention]

[0004] When the detection gas is delivered to the multiple sensor elements, the delivery may be uneven depending on the position of the sensor elements, which may result in detection errors due to the position of the sensor elements. In addition, when using pumps to selectively deliver the reference gas and the detection gas, multiple pumps must be installed, but the gas delivered to the sensor elements may be uneven depending on the pump positions. When a plurality of sensor elements and pumps are arranged as described above, the arrangement of each becomes complicated, which may result in a deterioration in airtightness and an increase in the number of assembly steps.

[0005] In view of the above circumstances, an object of the present invention is to provide a gas detection device capable of supplying gas uniformly to a plurality of sensor elements. [Means for solving the problem]

[0006] In order to achieve the above object, a gas detection device according to one aspect of the present invention includes a casing and a plurality of sensor elements. The casing has a gas inlet having an inlet, a first chamber communicating with the inlet, a second chamber communicating with the first chamber, a throttle portion restricting the flow of gas from the first chamber to the second chamber, and a gas exhaust portion communicating with the second chamber. The plurality of sensor elements are disposed in the second chamber and have different detection sensitivities depending on the gas species.

[0007] The casing may have a wiring board having a first main surface on which the plurality of sensor elements are mounted, and a case body attached to the peripheral portion of the first main surface in an airtight manner, and the first chamber and the second chamber may be partitioned between the wiring board and the case body.

[0008] The gas inlet section may be provided in the wiring board, and the gas exhaust section may be provided in the case body.

[0009] The wiring board may further have a second main surface opposite to the first main surface, and the gas introduction section may include a pump element mounted on the second main surface.

[0010] The case body may have an opening end fixed to the first main surface, a first bottom surface facing the first main surface and formed at a first depth from the opening end, and a second bottom surface facing the first main surface and formed at a second depth from the opening end that is shallower than the first depth. In this case, the difference between the first depth and the second depth may be equal to or less than half the first depth.

[0011] The case body may have a bottom portion facing the first main surface, and the drawn portion may be a wall-like protrusion portion provided upright on the bottom portion or the first main surface.

[0012] The casing may have a first case body having a gas introduction space including the first chamber and the second chamber, and a second case body attached to the first case body and blocking the gas introduction space, and the multiple sensor elements may be arranged in the first case body or the second case body.

[0013] The first case body may have an opening end fixed to the second case body, a first bottom surface formed at a first depth from the opening end, and a second bottom surface formed at a second depth from the opening end that is shallower than the first depth. In this case, the difference between the first depth and the second depth may be equal to or less than half the first depth.

[0014] The gas exhaust may have a smaller cross-sectional flow area than the second chamber. Effect of the Invention

[0015] According to the present invention, it becomes possible to supply gas uniformly to a plurality of sensor elements, and the measurement accuracy of the gas detection device can be improved. [Brief description of the drawings]

[0016] [Figure 1] 1 is a perspective view of a gas detection device according to a first embodiment of the present invention. [Diagram 2] 3A is a plan view showing the inside of a case body, FIG. 3B is a side cross-sectional view of the gas detector, and FIG. 3C is a plan view of the inside of a wiring board, showing the internal structure of the gas detector. [Diagram 3] FIG. 3 is a schematic diagram in which the gas flow in each part shown in FIGS. 2(A) to (C) is indicated by white arrows. [Figure 4] 4 is a schematic diagram similar to FIG. 3 but showing a gas detection device according to a comparative example. [Diagram 5]5A and 5B are diagrams showing the internal structure of a gas detection device according to a second embodiment of the present invention, in which (A) is a plan view showing the inside of a case body, (B) is a side cross-sectional view of the gas detection device, and (C) is a plan view of the inside of a wiring board. [Figure 6] FIG. 11 is a side sectional view showing the internal structure of a gas detection device according to a third embodiment of the present invention. [Figure 7] FIG. 11 is a side sectional view showing the internal structure of a gas detection device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] <First embodiment> [Gas detection device configuration] 1 is a perspective view of gas detection device 100 according to one embodiment of the present invention. In the figure, the X-axis, Y-axis, and Z-axis indicate three mutually orthogonal axial directions, which correspond here to the horizontal (short side) direction, vertical (long side) direction, and height (thickness) direction of gas detection device 100, respectively. Gas detection device 100 of the present embodiment includes a casing 10 and a plurality of sensor elements 11 capable of detecting the type of gas introduced into casing 10.

[0019] Casing 10 has wiring board 1 and case body 2, which are assembled together. Fig. 2 shows the internal structure of gas detection device 100, in which (A) is a plan view showing the inside of case body 2, (B) is a side cross-sectional view of gas detection device 100, and (C) is a plan view of the inside of wiring board 1.

[0020] The wiring board 1 has a first main surface 1a on which a plurality of sensor elements 11 are mounted, and a second main surface 1b on the opposite side. The first main surface 1a is an inner main surface facing the case body 2, and the second main surface 1b is an outer main surface exposed to the outside.

[0021] The wiring board 1 is a rectangular board with its long sides in the Y-axis direction, and is typically a double-sided wiring board having wiring layers formed on a first main surface 1a and a second main surface 1b. The wiring board 1 is typically a glass epoxy board, but other rigid boards such as ceramic boards and metal boards can also be used.

[0022] The case body 2 is in the shape of a substantially rectangular parallelepiped with one surface parallel to the XY plane removed to form an opening. The case body 2 has a peripheral wall 2s and a bottom 2b which define a gas introduction space 20. The peripheral wall 2s has an opening end 2a which is an end forming the opening of the case body 2. The opening end 2a is fixed to the periphery of the first main surface 1a of the wiring board 1 so as to maintain airtightness. The bottom 2b is located opposite the first main surface 1a of the wiring board 1. In this way, the gas introduction space 20 is formed between the wiring board 1 and the case body 2.

[0023] In this embodiment, the case body 2 is fixed to the wiring board 1 by a plurality of screw members. A sealing member (such as a packing) (not shown) is disposed between the first main surface 1a of the wiring board 1 and the opening end 2a of the case body 2, thereby ensuring airtightness between the wiring board 1 and the case body 2. The case body 2 is, for example, an injection-molded body made of a synthetic resin material. The type of resin material is not particularly limited, and is, for example, polytetrafluoroethylene.

[0024] The casing 10 has a gas inlet 12, a gas introduction space 20, and a gas exhaust section 23. The gas inlet 12 is provided in the wiring board 1, and the gas introduction space 20 and the gas exhaust section 23 are provided in the case body 2.

[0025] The gas introduction section 12 includes a pair of introduction ports 16, 17 formed in the wiring board 1, and pump elements 6, 7 arranged at the respective introduction ports. The introduction ports 16, 17 are holes penetrating the wiring board 1 in its thickness direction. The shape of the introduction ports 16, 17 is not limited to the rectangular shape shown in the figure, and may be a circular shape. The pump elements 6, 7 are connected to a gas source (not shown) and deliver gas from the gas source to the gas introduction space 20. The type of the pump elements 6, 7 is not particularly limited, and in this embodiment, they are, for example, motor-type or piezoelectric-type micro diaphragm pumps mounted on the second main surface 1b of the wiring board 1.

[0026] In this embodiment, a plurality of (two) gas introduction parts 12 are provided, but there may be only one, or three or more. One gas introduction part 12 (6, 16) is a gas introduction part for a reference gas, and the other gas introduction part 12 (7, 17) is a gas introduction part for a gas to be detected. The reference gas is typically dry air. The gas to be detected is appropriately selected depending on the specifications and applications, and examples thereof include CO2, C6H6, CO, NH3, and O2.

[0027] 2C, the gas introduction parts 12 are provided adjacent to each other in the horizontal direction in a region on one vertical side (-Y direction side) of the wiring board 1. Note that the gas introduction parts 12 are not limited to being provided in the wiring board 1, and may be provided in the case body 2.

[0028] The gas introduction space 20 is divided into a first chamber 21 and a second chamber 22. The first chamber 21 is provided directly below the gas introduction part 12 so as to communicate with the inlets 16, 17 of the gas introduction part 12. The second chamber 22 is provided between the first chamber 21 and the gas exhaust part 23 so as to communicate with the first chamber 22.

[0029] The case body 2 has a first bottom surface 211 facing the first main surface 1a of the wiring board 1 and formed at a first depth D1 from the opening end 2a, and a second bottom surface 221 facing the first main surface 1a of the wiring board 1 and formed at a second depth D2 from the opening end 2a that is shallower than the first depth D1. The first chamber 21 is a space between the first main surface 1a and the first bottom surface 211, and the second chamber 22 is a space between the first main surface 1a and the second bottom surface 221. A step portion 24 is formed between the first bottom surface 211 and the second bottom surface 221. The step portion 24 is formed at the boundary between the first chamber 21 and the second chamber 22.

[0030] The step portion 24 is provided so as to extend in the horizontal direction (X-axis direction) between the gas inlet portion 12 and the gas outlet portion 23 when viewed from the wiring board 1 side. The step portion 24 is a wall surface extending vertically from the bottom portion 2b of the case body 2 toward the wiring board 1, and constitutes a throttle portion that restricts the flow path of the gas flowing from the first chamber 21 to the second chamber 22. The height (D1-D2) of the step portion 24, which is the difference between the first depth D1 and the second depth D2, is not particularly limited, but is formed to an appropriate height that can restrict the inflow of the gas introduced into the first chamber 21 into the second chamber 22. In this embodiment, the height of the step portion 24 is set to a size equivalent to half or less of the depth of the first chamber 21.

[0031] Gas exhaust section 23 is a through hole formed in the side wall on the other vertical side (+Y direction side) of case body 2 so as to communicate with second chamber 22. Gas exhaust section 23 has a flow path cross-sectional area smaller than second chamber 22. The flow path cross-sectional area is the area of ​​the flow path perpendicular to the gas flow direction. The shape of gas exhaust section 23 is not particularly limited, and may be rectangular, circular, elliptical, or the like. Gas exhaust section 23 may also be a collection of multiple through holes.

[0032] The multiple sensor elements 11 each have different detection sensitivity depending on the gas species, and are, for example, QCMs (Quartz Crystal Microbalances). A QCM is a mass sensor that measures minute changes in mass by utilizing the property that when a detection target substance (gas) adheres to the electrode surface of a quartz oscillator, the resonant frequency fluctuates (decreases) depending on the mass. Note that the sensor element 11 is not limited to an example formed of a QCM sensor, and may be formed of a semiconductor sensor capable of detecting a specific gas species.

[0033] The multiple sensor elements 11 are mounted on a first main surface 1a of the wiring board 1 facing the gas introduction space 20. Each sensor element 11 has a sensitive film for adsorbing a target gas on the electrode surface of the quartz crystal resonator. This sensitive film is made of a different material for each sensor element 11. In this embodiment, there are eight sensor elements 11, and a different sensitive film is used for each sensor element 11, making it possible to detect eight types of gas.

[0034] Note that the present invention is not limited to an example in which one type of gas is detected by one sensor element 11, and one type of gas may be detected by multiple sensor elements 11. Also, one sensor element 11 may be configured to be capable of detecting multiple types of gas. In this case, it is preferable to use a sensitive film having different sensitivities depending on the gas type.

[0035] The sensor elements 11 are disposed on the first main surface 1a of the wiring board 1 in an area facing the second chamber 22. In this embodiment, eight sensor elements 11 are disposed in two rows and four columns, but the layout is not limited to this. The number of sensor elements 11 is not limited to eight, and can be set arbitrarily according to the number of gas species to be detected.

[0036] A temperature sensor 14 and a humidity sensor 15 are mounted on the first main surface 1a of the wiring board 1. The mounting areas of the temperature sensor 14 and the humidity sensor 15 are not particularly limited, and in this embodiment, they are disposed in any area between the sensor element 11 and the gas exhaust unit 23. When the QCM characteristics of the sensor element 11 are temperature-dependent, the output of the sensor element 11 is corrected based on the output of the temperature sensor 14. The humidity sensor 15 may be used as a sensor for detecting water vapor, for example. For example, a thermistor can be applied to the temperature sensor 14, and for example, a QCM sensor having a sensitive film that is adsorbent to water vapor can be applied to the humidity sensor 15. At least one of the temperature sensor 14 and the humidity sensor 15 may be omitted as necessary.

[0037] As shown in FIG. 1, a control board 50 is installed on the second main surface 1b side of the wiring board 1. A power supply circuit and a signal processing circuit are connected to the control board 50. The control board 50 is electrically connected to the wiring board 1, and supplies necessary power to each of the sensor elements 11, the pump elements 6 and 7, the temperature sensor 14, and the humidity sensor 15 via the wiring layer on the wiring board 1. The signal processing circuit detects the presence, type, amount, etc. of the detection target gas in the gas introduction space 20 based on the output of each of the sensor elements 11, the temperature sensor 14, and the humidity sensor 15. In addition to the above elements or sensors, other electronic components (for example, drive circuits for the pump elements 6 and 7) may be mounted on the control board 50.

[0038] [Gas detection device operation] Next, a typical operation of gas detection apparatus 100 of this embodiment configured as above will be described.

[0039] First, the pump element 6 for introducing the reference gas is driven to introduce the reference gas into the gas introduction space 20, and the output of each sensor element 11 is calibrated. After that, the driving of the pump element 6 is stopped, and the pump element 7 for introducing the target gas is driven to introduce the target gas into the gas introduction space 20. The target gas to be introduced is typically a gas that is detected by any one of the multiple sensor elements 11, but may of course be another gas. Hereinafter, the target gas may also be simply referred to as gas.

[0040] Gas introduced from gas inlet part 12 (7, 17) passes through gas detection device 100 in the order of first chamber 21, second chamber 22, and gas outlet part 23. Figures 3(A) to (C) are schematic diagrams in which the gas flow in each part shown in Figures 2(A) to (C) is indicated by outline arrows.

[0041] 3(A) and (B), the gas introduced from gas introduction part 12 into first chamber 21 is isotropically diffused in a turbulent state within first chamber 21 because the step 24 restricts the gas from flowing into second chamber 22. In other words, step 24 functions as a throttle formed between first chamber 21 and second chamber 22, and the gas introduced into first chamber 21 flows into second chamber 22 in a laminar flow state.

[0042] This allows the gas introduced into first chamber 21 to be uniformly supplied throughout second chamber 22, regardless of the position of gas introduction part 12. In addition, since gas introduction part 12 is provided on wiring substrate 1 so as to face the bottom (first bottom surface 211) of first chamber 22, the gas diffusion effect in first chamber 21 can be further improved.

[0043] On the other hand, the gas that has flowed into the second chamber 22 flows toward the gas exhaust section 23 along the first main surface 1a of the wiring board 1 on which the multiple sensor elements 11 are mounted. Since the gas exhaust section 23 has a smaller flow passage cross-sectional area than the second chamber 22, the gas pressure in the second chamber 22 is higher than that on the outlet side of the gas exhaust section 23. This can improve the gas detection sensitivity of the sensor element 11. In addition, since the gas that has flowed into the second chamber 22 flows toward the gas exhaust section 23 in a laminar flow state, the gas is uniformly supplied to the multiple sensor elements 11 on the wiring board 1. This can realize a highly accurate gas detection operation regardless of the position of the sensor element 11.

[0044] For example, as a comparative example, Figures 4(A) to (C) show schematic diagrams of gas flow in a case where the gas introduction space 20 does not have a step 24 and the gas exhaust section 23 is formed with the same width and height as the gas introduction space. In this case, the gas introduction space 20 does not have a step 24 (see Figure 3) that functions as a throttle section, so the gas flow rate in the gas introduction space 20 tends to be higher in an area closer to the gas introduction section 12 (7, 17) and lower in an area farther from the gas introduction section 12 (7, 17). As a result, the gas does not come into uniform contact with the sensor element 11, and the detection sensitivity varies depending on the position of the sensor element 11, which may result in a decrease in gas detection accuracy.

[0045] In contrast, according to this embodiment, as described above, gas can be uniformly transported to the multiple sensor elements 11 having different detection sensitivities according to the gas species, so that highly accurate gas detection can be performed regardless of the gas introduction position or the sensor element position. This allows the identification and amount of the introduced gas to be detected with high accuracy.

[0046] Even if the type of introduced gas is unknown, it is possible to identify the type of introduced gas based on the output of each of the multiple sensor elements 11. Conventionally, a sensor element prepared for a specific target gas was required, and it was impossible to identify the type of an unknown gas, but according to this embodiment, gas can be supplied uniformly to multiple sensors, making it possible to simultaneously identify the gas type and measure the gas concentration.

[0047] Furthermore, in the past, when calibrating sensors using a reference gas, or when multiple pumps were required for each sensor element, but with this technology, one pump each for the reference gas and the detection gas, and for the detection gas, one pump can be used to detect gas types even for multiple sensors, and the pump and sensors can be placed on the same board, offering great advantages in terms of manufacturing costs, size and weight reduction.

[0048] <Second embodiment> 5A and 5B show the configuration of a gas detection device 200 according to a second embodiment of the present invention, in which (A) is a plan view showing the inside of case body 2, (B) is a side cross-sectional view of gas detection device 200, and (C) is a plan view of the inside of wiring board 1. Hereinafter, configurations different from the first embodiment will be mainly described, and configurations similar to those in the first embodiment will be denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0049] The gas detection device 200 of this embodiment differs from the first embodiment in that the first and second chambers 21, 22 that constitute the gas introduction space 20 are both formed to the same depth, and a wall-shaped protrusion portion 25 is provided between the first and second chambers 21, 22 as a throttling portion.

[0050] 5(A) and (B), the wall-like protrusion 25 is erected on the bottom 2b of the case body 2 so as to extend linearly in the horizontal direction (X-axis direction), and forms the boundary between the first chamber 21 and the second chamber 22. The height of the wall-like protrusion 25 is not particularly limited, but is formed to an appropriate height that can restrict the inflow of gas introduced into the first chamber 21 into the second chamber 22. In this embodiment, the height of the wall-like protrusion 25 is set to a size equivalent to half or less of the depth of the first chamber 21. The width (width dimension along the Y-axis direction) of the wall-like protrusion 25 is also not particularly limited.

[0051] Gas detection device 200 of the present embodiment configured as described above can also provide the same operational effects as those of the above-described first embodiment. According to the present embodiment, the operational effects described above can be obtained simply by forming wall-like protrusion 25 on the inner surface of bottom 2b of case body 2, so that the amount of material constituting case body 2 can be reduced.

[0052] In this embodiment, the wall-shaped protrusion 25 is provided on the bottom 2b of the case body 2, but the present invention is not limited to this. For example, the wall-shaped protrusion 25 may be provided on the first main surface 1a of the wiring board 1, and the same effect as described above can be obtained in this case as well.

[0053] <Third embodiment> 6 is a side cross-sectional view showing the configuration of gas detection device 300 according to the third embodiment of the present invention. Below, configurations different from the first embodiment will be mainly described, and configurations similar to those in the first embodiment will be denoted by the same reference numerals and descriptions thereof will be omitted or simplified.

[0054] Gas detection apparatus 300 of the present embodiment differs from that of the above-described first embodiment in the structure of casing 310 that forms gas introducing space 20. In this embodiment, it is configured by combining first case body 2A and second case body 2B.

[0055] The first case body 2A corresponds to the case body 2 in the first embodiment, and has a peripheral wall portion 2s and a bottom portion 2b that define the gas introduction space 20, and a gas discharge portion 23. An opening end portion 2a, which is an end portion of the peripheral wall portion 2s, is airtightly fixed to the second case body 2B. The bottom portion 2b has a first bottom surface 211 formed at a first depth D1 from the opening end portion 2a, and a second bottom surface 221 from the opening end portion 2a, as in the first embodiment.

[0056] The gas introduction space 20 is divided into a first chamber 21 and a second chamber 22. The first chamber 21 is a gap between the second case body 2B and the first bottom surface 211, and the second chamber 22 is a gap between the second case body 2B and the second bottom surface 221. A step 24 forming a boundary between the first chamber 21 and the second chamber 22 is provided between the first bottom surface 211 and the second bottom surface 221. The height (D1-D2) of the step 24, which is the difference between the first depth D1 and the second depth D2, is set to a size equivalent to, for example, half or less of the depth of the first chamber 21.

[0057] The second case body 2B is attached to the open end 2a of the first case body 2A and closes the gas introduction space 20. The second case body 2B is made of the same material as the first case body 2A, and in this embodiment, is made of a molded body made of a synthetic resin material.

[0058] The second case body 2B has a housing portion 8 that houses the wiring board 1 having a plurality of sensor elements 11 mounted thereon. The housing portion 8 is a through hole formed in the second case body 2B in its thickness direction (Z-axis direction), and the wiring board 1 is airtightly fixed to the housing portion 8 such that the plurality of sensor elements 11 face the second bottom surface portion 221. In this way, the plurality of sensor elements 11 are disposed in the second chamber 22.

[0059] The second case body 2B has a pair of inlets 16, 17 that accommodate the pump elements 6, 7. The pair of inlets 16, 17 are through holes formed in the second case body 2B in its thickness direction (Z-axis direction), and the pump elements 6, 7 are airtightly fixed to the pair of inlets 16, 17 so as to face the first bottom surface portion 211. This embodiment differs from the first embodiment in that the pump elements 6, 7 are disposed directly on the gas inlets 16, 17, not on the wiring board 1. In addition, the pump elements 6, 7 are electrically connected to a drive circuit mounted on, for example, a control board 50 (see FIG. 1).

[0060] Gas detection device 300 of the present embodiment configured as above can also provide the same effects as those of the above-mentioned embodiments. In the present embodiment, casing 310 is configured by first case body 2A and second case body 2B, so that the strength of casing 310 can be improved and wiring board 1 on which multiple sensor elements 11 are mounted can be made smaller.

[0061] <Fourth embodiment> 7 is a side cross-sectional view showing the configuration of a gas detection device 300 according to a seventh embodiment of the present invention. Below, configurations different from the third embodiment will be mainly described, and configurations similar to those in the third embodiment will be given the same reference numerals and descriptions thereof will be omitted or simplified.

[0062] Gas detection device 400 of the present embodiment differs from that of the above-described third embodiment in that wiring board 1 on which a plurality of sensor elements 11 are mounted is disposed in first case body 2A.

[0063] In this embodiment, the first case body 2A has a housing portion 9 that houses the wiring board 1 having a plurality of sensor elements 11 mounted thereon. The housing portion 9 is a through hole formed in the first case body 2A in its thickness direction (Z-axis direction), and the wiring board 1 is airtightly fixed to the housing portion 9 so that the plurality of sensor elements 11 are disposed in the second chamber 22.

[0064] Gas detection device 400 of the present embodiment configured as above can also provide the same operational effects as those of the above-described embodiments. Note that pump elements 6, 7 are disposed in second case body 2B, but are not limited to this, and may be disposed in first case body 2A similarly to wiring board 1. [Explanation of symbols]

[0065] 1...Wiring board 1a...First main surface 1b…Second main surface 2. Case body 2A…First case body 2B: Second case body 6,7…Pump element 11...Sensor element 12...Gas inlet 20…Gas introduction space 21…First chamber 22…Second chamber 23...Gas exhaust section 24...Stepped portion (throttled portion) 25...Wall-shaped protrusion (throttling part) 100, 200, 300, 400...Gas detection equipment 211…First bottom 221…Second bottom

Claims

1. a casing having an inlet, a first chamber communicating with the inlet, a second chamber communicating with the first chamber, a restrictor portion that restricts a flow of gas from the first chamber to the second chamber, and a gas exhaust portion communicating with the second chamber; a plurality of sensor elements disposed in the second chamber and having different detection sensitivities depending on the gas species; A gas detection device comprising:

2. 2. The gas detection device according to claim 1, the casing includes a wiring board having a first main surface on which the plurality of sensor elements are mounted, and a case body attached to a peripheral portion of the first main surface in an airtight manner; The first chamber and the second chamber are defined between the wiring board and the case body. Gas detection equipment.

3. 3. The gas detection device according to claim 2, The inlet is provided in the wiring board, The gas exhaust section is provided in the case body. Gas detection equipment.

4. 4. The gas detection device according to claim 3, the wiring board further has a second main surface opposite to the first main surface, The inlet is provided with a pump element. Gas detection equipment.

5. The gas detection device according to any one of claims 2 to 4, The case body has an opening end fixed to the first main surface, a first bottom surface facing the first main surface and formed at a first height from the opening end, and a second bottom surface facing the first main surface and formed at a second height from the opening end that is lower than the first height. Gas detection equipment.

6. The gas detection device according to any one of claims 2 to 4, the case body has a bottom portion facing the first main surface, The narrowed portion has a wall-shaped protrusion portion provided upright on the bottom portion or the first main surface. Gas detection equipment.

7. 2. The gas detection device according to claim 1, the casing has a first case body and a second case body connected to each other so as to form the first chamber, the second chamber and the throttle portion therein, the second case body having the inlet formed therein; The plurality of sensor elements are disposed in the first case body or the second case body. Gas detection equipment.

8. 8. The gas detection device according to claim 7, The first case body has an open end fixed to the second case body, a first bottom surface formed at a first height from the open end, and a second bottom surface formed at a second height from the open end that is lower than the first height. Gas detection equipment.

9. 9. The gas detection device according to claim 5 or 8, The difference between the first height and the second height is equal to or less than half the first height. Gas detection equipment.

10. The gas detection device according to any one of claims 1 to 9, The gas exhaust portion has a smaller flow cross-sectional area than the second chamber. Gas detection equipment.

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