Gas detection device

Abstract

To provide a gas detection device comprising a gas sensor with improved response speed.SOLUTION: A gas detection device 100 provided herein comprises a housing 10, a gas sensor main body 30 installed in the housing 10, and a partition wall 22 provided in the housing 10 to limit and separate the periphery of the gas sensor main body 30 from other areas. The housing 10 or the partition wall 22 is provided with an opening 23 that keeps the outside in direct communication with a region inside the partition wall 22.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas detector that measures the concentration of a target gas in the atmosphere, and particularly relates to a technique for improving the response speed of a gas sensor provided in a housing of this type of gas detector. Background Art

[0002] Conventionally, as an apparatus for measuring the concentration of a target gas in the atmosphere, a gas detector including a non-dispersive infrared gas sensor that measures the gas concentration by detecting the absorption amount based on the fact that different gas types absorb different infrared wavelengths has been used.

[0003] As this type of apparatus, for example, a gas detector is known (see, for example, Patent Document 1). Prior Art Documents Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Publication No. 9-79980 Summary of the Invention Problems to be Solved by the Invention

[0005] Here, in order to satisfy the safety standards imposed on this type of gas detector, a faster response speed of the gas sensor is desired. In contrast, to improve the response speed of the gas sensor provided in the gas detector, it is necessary to quickly replace the air around the gas sensor body in the housing. For example, a method of generating an air flow by installing a fan is also conceivable, but there is a limit to improving the exhaust performance in the housing, and it may also cause a thermally unstable situation.

[0006] Therefore, the present invention has been made in view of these problems, and aims to provide a gas detection device that can improve the response speed of a gas sensor inside a housing. [Means for solving the problem]

[0007] To solve the above problems, a gas detection device according to one aspect of the present invention comprises a housing, a gas sensor body installed inside the housing, and a partition wall provided inside the housing that limits the area around the gas sensor body and separates it from other areas, wherein the housing or the partition wall is provided with an opening that allows direct communication from the outside to an area inside the partition wall.

[0008] According to one aspect of the present invention, a partition wall is provided inside the housing to restrict the area around the gas sensor body and separate it from other areas inside the housing, and an opening is provided in the housing that connects the inside of the partition wall to the outside. Compared to a structure that replaces the entire air inside the housing, the air inside the partition wall surrounding the gas sensor body can be replaced more quickly. As a result, a response speed that meets the safety standards imposed on gas sensors can be obtained with a simple housing structure.

[0009] Furthermore, in order to solve the above problems, another gas detection device according to the present invention is characterized by comprising a housing, a gas sensor body installed inside the housing, and a metal cage arranged to surround the gas sensor body and heated by a heater.

[0010] In another embodiment of the present invention, a metal cage is provided inside the housing, which is arranged to surround the gas sensor body and heated by a heater. This allows for efficient heating of the gas sensor body and the space surrounding it. As a result, a thermally stable space can be secured around the gas sensor body in the narrowest possible area, thereby improving the response speed of the gas sensor inside the housing. [Effects of the Invention]

[0011] As described above, the present invention makes it possible to improve the response speed of the gas sensor inside the housing. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view illustrating a first embodiment of a gas detection device according to one aspect of the present invention. [Figure 2] These are schematic cross-sectional views (a) and (b) illustrating a second embodiment of a gas detection device according to one aspect of the present invention. [Figure 3] This is an explanatory diagram showing a first embodiment of a gas detection device according to one aspect of the present invention, where (a) is a perspective view, (b) is a front view, and (c) is a ZZ cross-sectional view at (b). [Figure 4] Figure 3 is an exploded perspective view of the main components of the gas detection device. [Figure 5] Figure 3 is an explanatory diagram of the sensor body and circuit board, with (a) being a perspective view and (b) being an exploded perspective view. [Figure 6] Figure 3 is an explanatory diagram of another example (second embodiment) of the sensor body and substrate portion, where (a) is a perspective view and (b) is an exploded perspective view. [Figure 7] This is an explanatory diagram showing a modified example (first modified example) of the housing structure of a gas detection device according to one aspect of the present invention, where (a) is a perspective view, (b) is a front view, and (c) is a ZZ cross-sectional view at (b). [Figure 8] This is an explanatory diagram showing a modified example (second modified example) of the housing structure of a gas detection device according to one aspect of the present invention, where (a) is a perspective view, (b) is a front view, and (c) is a ZZ cross-sectional view at (b). [Modes for carrying out the invention]

[0013] Embodiments and examples (including modifications) of the present invention will be described below with appropriate reference to the drawings. Note that the drawings are schematic. Therefore, it should be noted that the relationship and ratios between thickness and planar dimensions may differ from those in reality, and there may be differences in dimensional relationships and ratios between drawings. Furthermore, the embodiments and examples shown below illustrate devices and methods for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited to the following embodiments and examples in terms of the material, shape, structure, arrangement, etc., of the components.

[0014] [First Embodiment] First, the gas detection device of the first embodiment will be described. Figure 1 shows a schematic cross-sectional view of the gas detection device of the first embodiment. As shown in the figure, the gas detection device 100 of the first embodiment comprises a housing 10, a gas sensor body 30 provided inside the housing 10, and a partition wall 22 surrounding the gas sensor body 30 to define a small-volume cavity space CA. In the figure, the defined cavity space CA is shown with shading. In the gas detection device 100 of the first embodiment, the cavity space CA is a space enclosed by a part of the housing 10 and the partition wall 22.

[0015] The gas sensor body 30 has a non-dispersive infrared optical cell that measures the gas concentration by detecting the amount of infrared light absorbed, taking advantage of the fact that different types of gases absorb different wavelengths of infrared light (the same applies to other embodiments below). Although a detailed explanation will be omitted, the optical cell has an inlet and outlet for the gas to be measured at the top, a cover portion with a cavity formed inside, and element portions such as a reflector, a light emitter, and a light receiver provided within the cavity of the cover portion, and is arranged to form a predetermined optical path (the same applies hereinafter).

[0016] A housing 10 of the first embodiment includes a lower base portion 11 and an upper cover portion 12. A PCB substrate 60 is clamped and fixed between the base portion 11 and the cover portion 12. The upper center of the cover portion 12 serves as an inlet / outlet for the gas to be measured, and an opening 23 that directly communicates from the outside with the cavity space CA, which is a region inside the partition wall 22, is provided, and a particle filter 24 for gas exchange is attached to the opening 23. In other words, the opening 23 does not communicate the cavity space CA with other regions, but directly communicates the outside of the housing with the cavity space CA. The particle filter 24 and the surrounding portion thereof are covered by an inlet cover 50, which prevents dust and raindrops from entering the particle filter 24. The hollow arrow attached to the inlet cover 50 shows an image of the airflow through which the gas to be measured is introduced and discharged.

[0017] On the PCB substrate 60, the gas sensor main body 30 described above is mounted at the center of the substrate, and a PID regulator 81 is mounted on the lateral side of the substrate. Furthermore, on the back surface of the PCB substrate 60, a heater 80 constituted by a resistance heater, a heating transistor, or the like is mounted at a position facing the gas sensor main body 30.

[0018] In the example of the first embodiment, in the gas detection device 100 of the first embodiment, the gas sensor main body 30 housed in the housing 10 is surrounded by the partition wall 22 as a compartment that separates only the periphery of the non-dispersive infrared absorption type gas sensor main body 30 from other regions inside the housing 10.

[0019] Other regions that are regions other than the cavity space CA, that is, the region outside the partition wall 22 in the upper cover portion 12, and the region 90 defined by the base portion 11 on the back surface side of the PCB substrate 60, are other regions where members necessary for the gas detection device such as electronic components including auxiliary electronic devices, interfaces, communication units, heater control units, and connectors are arranged.

[0020] Here, the area other than the cavity space CA is completely surrounded by the housing 10 and the partition wall 22, and there are no inlet or outlet for the gas to be measured, with only the cavity space CA communicating with the outside through the opening 23. However, inlet and outlet for the gas to be measured may also be provided in the area other than the cavity space CA.

[0021] The cavity space CA is significantly smaller than the other regions, with its volume being less than half the volume of the other regions. More preferably, the volume of the cavity space CA is less than one-third the volume of the other regions. Furthermore, the height, width, and depth of the cavity space CA are less than or equal to twice the height, width, and depth of the gas sensor 30, respectively.

[0022] Next, the operation and effects of the gas detection device 100 of the first embodiment will be described. As described above, in the gas detection device 100 of the first embodiment, the gas sensor body 30 is provided with a partition wall 22 located inside the housing 10 that limits the area around the gas sensor body 30 and separates it from other areas, and the housing 10 is provided with an opening 23 that directly communicates with the cavity space CA from the outside.

[0023] As a result, according to the gas detection device 100 of the first embodiment, the partition wall 22 defines a small-volume cavity space CA around the gas sensor body 30, and the gas to be measured is directly introduced and discharged into the cavity space CA from the opening 23, so that the area around the gas sensor body 30 can be ventilated quickly and separately from other areas. Therefore, a high-speed response of the gas sensor body 30 within the housing 10 becomes possible.

[0024] Furthermore, since the volume of the cavity space CA is less than half the volume of the other regions, the gas sensor body 30 can respond more quickly within the housing 10.

[0025] Furthermore, since the gas detection device 100 is equipped with an inlet cover 50 that covers the opening 23, it is possible to prevent dust and raindrops from entering the opening 23, even though the opening 23 has direct communication with the cavity space CA from the outside.

[0026] Furthermore, electronic components are located in other areas of the housing 10, and only the cavity space CA is in communication with the outside through the opening 23. Therefore, while the target gas can be quickly introduced and discharged into the cavity space CA, the target gas cannot be introduced or discharged into other areas, and the intrusion of dust and raindrops can also be prevented, thereby reducing the failure rate of electronic components located in other areas.

[0027] [Second Embodiment] Next, a gas detection device of the second embodiment will be described. Figure 2 is a schematic cross-sectional view of the main part of the gas detection device 100 of the second embodiment. In the figure, (a) shows the first aspect of the second embodiment, and (b) shows the second aspect. Components that are the same as or corresponding to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate (the same applies to other embodiments and modifications below).

[0028] As shown in Figure (a), in the gas detection device 100 of the second embodiment (first aspect), a gas sensor body 30 and a compartment cover 20 that surrounds it are provided inside a housing (not shown in the figure). In the second embodiment (first embodiment), the side wall portion of the compartment cover 20 corresponds to the partition wall 22 of the first embodiment. Furthermore, the upper surface of the compartment cover 20 becomes part of the housing, forming an opening 23, and the opening 23 becomes a mounting surface 21 on which the particle filter 24 is attached. In Figure (a), the image of the introduction and discharge of the target gas from the upper opening 23 is illustrated by multiple arrows. The opening 23 allows for the direct introduction and discharge of the target gas into the cavity space CA from the outside.

[0029] Furthermore, in the gas detection device 100 of the second embodiment, in addition to the partition wall 22 of the first embodiment, a metal cage 40 is further provided in the cavity space CA. The cage 40 of the second embodiment is soldered to the copper surface 61 of the PCB substrate 60 on which the gas sensor body 30 is mounted. As a result, the cage 40 is positioned so that within the cavity space CA, a small portion of the space including the gas sensor body 30 and its surrounding area is further defined by the area within the partition wall 22. In the example shown in the figure, the small portion of the space including the gas sensor body 30 and its surrounding area within the cavity space CA is shown with shading.

[0030] Furthermore, in the gas detection device 100 of the second embodiment, a heating transistor is used as the heater 80. In the example shown in the figure, two heaters 80 are used; one heater 80 is directly attached to the metal cage 40, and the other heater 80 is directly attached to the copper surface 61 of the PCB substrate 60. Each heater 80 is controlled by a heater control unit (not shown).

[0031] The effects and advantages of the gas detection device 100 of the second embodiment will now be described. Note that explanations of effects and advantages similar to or corresponding to those of the first embodiment will be omitted as appropriate (the same applies to other embodiments and modifications below). As described above, in the gas detection device 100 of the second embodiment, a metal cage 40 is provided inside the partition wall 22 within the cavity space CA, further surrounding the gas sensor body 30 and heated by the heater 80.

[0032] Therefore, according to the gas detection device 100 of the second embodiment, the cage 40 can more effectively transfer the heat from the heater 80 to the gas sensor body 30 and its surroundings. Furthermore, a more suitable thermally stable space can be secured within the cage 40 itself and the area enclosed by the cage 40. Thus, an even faster response becomes possible for the gas sensor body 30 inside the housing 10.

[0033] In the example of the second embodiment, a metal cage 40 is provided inside the partition wall 22 within the cavity space CA, further surrounding the gas sensor body 30 and heated by the heater 80. However, the invention is not limited to this, and in order to improve the response speed of the gas sensor body 30 in the gas detection device 100, the partition wall 22 can be omitted (i.e., without defining the cavity space CA), and a metal cage 40 that surrounds the gas sensor body 30 and is heated by the heater 80 can simply be provided.

[0034] Even with this configuration, since a metal cage 40 is provided inside the housing 10, at least surrounding the gas sensor body 30 and heated by the heater 80, the gas sensor body 30 and the space around it can be heated efficiently. As a result, a thermally stable space can be secured around the gas sensor body 30 in the narrowest possible area, thereby improving the response speed of the gas sensor inside the housing 10.

[0035] Furthermore, as shown in the first and second embodiments (first aspect) above, the location of the gas sensor body 30 located in a small-capacity cavity space CA or metal cage 40 is not limited to the top, but can be formed in any suitable location as long as it is possible to directly introduce and discharge the gas to be measured into the cavity space CA or metal cage 40 from the outside.

[0036] For example, as shown in Figure (b) for a second embodiment, the PCB substrate 60 on which the gas sensor body 30 is mounted may be made part of the housing without providing an opening above the gas sensor body 30, and an opening 23 may be formed in the PCB substrate 60 to introduce and discharge the gas to be measured. In Figure (b), the image of the gas to be measured being introduced and discharged from the opening 23 on the substrate side into the cavity space CA or into the metal cage 40 is illustrated by multiple arrows. Furthermore, although not shown in the diagram, if there is a portion of the partition wall 22 that is in direct contact with the outside, an opening 23 may be provided in the portion of the partition wall 22 that is in direct contact with the outside, without providing an opening above the gas sensor body 30.

[0037] Furthermore, the metal cage 40 heated by the heater 80 is not limited to cases where the heater 80, such as a heating transistor, is directly attached to the cage 40. In other words, the cage 40 is soldered to the copper surface 61 of the PCB substrate 60 on which the gas sensor body 30 is mounted, as shown in the second embodiment in Figure (b).

[0038] Therefore, the metal cage 40 can also be effectively heated by the heater 80 attached to the copper surface 61 of the PCB substrate 60. The heater 80 may be attached to either the front or back surface of the PCB substrate 60. Figure (b) shows an example in which the heater 80 is attached to both the front and back surfaces of the PCB substrate 60.

[0039] [First Example] The present invention will be described in more detail below based on examples. Figure 3 shows the first embodiment. As shown in the figure, the gas detection device 100 of the first embodiment comprises a roughly rectangular parallelepiped housing 10, a gas sensor body 30 mounted on a rectangular PCB substrate 60 in plan view inside the housing 10, and a partition wall 22 surrounding the gas sensor body 30 inside the housing 10 (see Figure (c)).

[0040] The gas sensor body 30 has a roughly rectangular parallelepiped appearance and is composed of an optical cell, which is not shown in the figures below. As described above, the optical cell has an inlet and outlet for the gas to be measured at the top, and a cover portion with a cavity formed inside, and element portions such as a reflecting portion, a light-emitting portion and a light-receiving portion inside the cavity of the cover portion, and is arranged to form a predetermined optical path. The gas sensor body 30 is configured such that when the gas to be measured is introduced into the optical cell, the gas to be measured passes between the light-emitting unit, the light-receiving unit and the reflecting unit, and the concentration of the gas to be measured is calculated by the concentration calculation unit based on the output signal of the light-receiving unit at this time.

[0041] Furthermore, the light-emitting element is not particularly limited as long as it outputs light that includes wavelengths absorbed by the gas being measured. Specific examples include MEMS (microelectromechanical systems) light sources and light-emitting diodes. Furthermore, a photodiode may be preferable as the light-receiving element. The photodiode is preferably sensitive to a light band that includes the wavelength absorbed by the gas being measured. The shape of the photodiode is not particularly limited as long as a sufficient signal-to-noise ratio can be obtained.

[0042] The housing 10 is, for example, a rectangular parallelepiped-shaped plastic environmental box (an outer box with low thermal conductivity) with dimensions of approximately 130 mm in width, 130 mm in height, and 52 mm in depth. The housing structure of the gas detection device 100 in the first embodiment is determined by the concept of thermal stabilization according to the present invention, as schematically shown in the first embodiment. In particular, the partition wall 22 is installed so as to surround the physical dimensions of the gas sensor body 30, which first needs to be established thermally stably, with the smallest possible area. In Figure (c), the area of ​​the cavity space CA defined by the partition wall 22 is shown with shading.

[0043] More specifically, the housing 10 of the first embodiment has a lower base portion 11, an upper cover portion 12, and a compartment cover 20, as shown in the exploded perspective view in Figure 4. A PCB substrate 60 is sandwiched and fixed between the base portion 11 and the cover portion 12. A rectangular parallelepiped insulating member 70 is fitted into the central part of the base portion 11. Inserts 15 are inserted into the four corners on the back side of the cover portion 12, and the base portion 11 and the cover portion 12 are fixed together by fixing bolts 14 with washers 13 interposed from the lower surface side of the base portion 11, which faces the inserts 15 at the four corners in the axial direction.

[0044] The cover portion 12 has a rectangular opening in the upper center, and the compartment cover 20 is attached to cover this opening. The partition wall 22 in the first embodiment is formed by this compartment cover 20. In other words, the compartment cover 20 in the first embodiment has an upper mounting surface 21 and a partition wall 22 that protrudes downward from the back surface 21 to partition a rectangular area.

[0045] The airtightness around the upper edge of the partition wall 22 is maintained by interposing an O-ring 17 between the cover portion 12 of the housing 10 and the compartment cover 20. Similarly, the airtightness around the lower edge of the partition wall 22 is maintained by interposing an O-ring 18 between the base portion 11 of the housing 10 and the compartment cover 20.

[0046] In the first embodiment, the compartment cover 20 has a rectangular opening 23 in the center of the upper mounting surface 21, which serves as an inlet and outlet for the gas to be measured, and a gas exchange particle filter 24 is mounted so as to cover this opening 23. Furthermore, an inlet cover 50 is detachably provided at the upper opening 23 of the compartment cover 20 by cover fixing screws 51, and this inlet cover 50 prevents dust and raindrops from entering the opening 23.

[0047] The PCB board 60 is positioned so as to be in contact with the rectangular frame-shaped bottom surface of the partition wall 22. The pin header 31 of the gas sensor body 30 is soldered to the approximate center of the upper surface of the PCB board 60, and the gas sensor body 30 is mounted thereon. Furthermore, the upper part of the partition wall 22 is covered by a plastic wall that closes the upper opening of the housing 10, forming a mounting surface 21. Airtightness is maintained between the upper opening of the base portion 11 of the housing 10 and the PCB substrate 60 by interposing an O-ring 19.

[0048] Thus, in the first embodiment, the gas sensor body 30 is placed in a small cavity space CA defined by a rectangular frame-shaped partition wall 22 formed by the compartment cover 20. The areas of the housing 10 other than the cavity space CA are occupied by electronic components such as auxiliary electronic equipment, interfaces, communication units, and heater control units (not shown below), as well as components such as connectors.

[0049] In the first embodiment, the heater 80 is located on the opposite side of the PCB board 60 from the gas sensor body 30. In the first embodiment, the PCB board 60 equipped with the heater 80, which is a resistor heater or a heating transistor, allows heating of the gas sensor body 30 and the cavity space CA from the back side of the PCB board 60. Similar to the first embodiment, the heater 80 uses a simple regulator, thereby maintaining a constant temperature for the gas sensor body 30.

[0050] Furthermore, in the first embodiment, as shown in Figure 5, a metal cage 40 is provided within the cavity space CA, further surrounding the gas sensor body 30 with four side walls 42.

[0051] The cage 40 of the first embodiment is formed from a metal plate member and has a rectangular bottom portion that contacts the upper surface of the PCB substrate 60. Four side walls 42 are formed by folding upward from each of the four sides of this rectangular bottom portion. Therefore, the cage 40 of the first embodiment does not cover the area above the gas sensor body 30.

[0052] The bottom surface is wide to efficiently transfer heat and is mounted in close contact with the top surface of the PCB substrate 60. In addition, a rectangular retaining plate 32 with high heat transfer properties is interposed between the top surface of the bottom surface of the cage 40 and the back surface of the gas sensor body 30, in close contact with both.

[0053] The retaining plate 32 securely holds the gas sensor body 30 in its mounting position and ensures that the cage 40 and the gas sensor body 30 are in close contact, thereby further improving thermal conductivity. The heat generated by the PCB board 60, which is equipped with a heater 80 consisting of a resistance heater or a heating transistor, is directly transmitted by the heater 80 to the metal cage 40, thereby maintaining the area around the gas sensor body 30 at a desired temperature.

[0054] In the first embodiment, a 3W resistor heater 80 is provided as a heater 80 at a suitable location on the back surface of the PCB substrate 60, and a PID regulator (not shown) is provided to control this heater 80. The PID regulator is composed of a very simple regulator and is capable of controlling the temperature parameter of the gas sensor body 30 within a predetermined range.

[0055] Next, the operation and effects of the gas detection device 100 of the first embodiment will be described. As described above, in the gas detection device 100 of the first embodiment, the gas sensor body 30 is placed in a cavity space CA surrounded by the partition wall 22 of the compartment cover 20, in isolation from other areas.

[0056] In this case, the infrared gas sensor body 30 is typically very sensitive to fluctuations in humidity and airflow. Therefore, the intended performance of this type of gas sensor body 30 is guaranteed by the necessary calibration in an outdoor environment.

[0057] In contrast, according to the configuration of the first embodiment, a cavity space CA is created by a partition wall 22 surrounding the gas sensor body 30 inside the housing 10, thereby providing excellent performance even in harsh cold outdoor environments.

[0058] In other words, in the gas detection device 100 of the first embodiment, even if the environment in which the gas detection device 100 is installed is at an extremely low temperature of, for example, -40°C, the gas sensor body 30 inside the housing 10 is maintained at, for example, +20°C, thereby ensuring thermal stabilization of the gas sensor body 30. As a result, the responsiveness of the gas sensor body 30 is improved and its operation becomes stable, and in the example of the first embodiment, stable operation can be achieved with power consumption of about 70% of the maximum power.

[0059] Furthermore, in the first embodiment, as shown in Figure 5, a metal cage 40 is provided that surrounds the gas sensor body 30 with four side walls 42. This metal cage 40 more effectively transfers heat from the heater 80 to the gas sensor body 30, and more favorably secures a thermally stable space in the narrowest possible area within the cage 40 and the four side walls 42 in the cavity space CA.

[0060] In particular, in the first embodiment, as shown in Figure 5, heat from the heater 80 can be effectively transferred through the copper surface 61 of the PCB substrate 60 via the metal cage 40. Therefore, even with a heat transfer structure from only one side of the PCB substrate 60, the gas sensor body 30 and the cavity space CA can be efficiently heated. As a result, heat from the heater 80 can be effectively transferred to the desired range to ensure stable operation of the gas sensor body 30 and a uniform temperature. In the operation of the gas sensor body 30 in the first embodiment, a fast response time of only 15 seconds is achieved.

[0061] Next, another example of the metal cage 40 (second embodiment) will be described. Figure 6 is an explanatory diagram of the sensor body and substrate portion according to the second embodiment, where (a) is a perspective view and (b) is an exploded perspective view.

[0062] As shown in the figure, the second embodiment, like the first embodiment, is configured such that the gas sensor body 30, which is surrounded by the partition wall 22 of the compartment cover 20, is surrounded by a metal cage 40 to define an even smaller area within the cavity space CA. In particular, in the second embodiment, the roof portion 41 and side wall portions 42 of the metal cage 40 surround the gas sensor body 30 with good thermal conductivity, forming one roof portion 41 and four side wall portions 42.

[0063] In other words, while the cage 40 of the first embodiment did not cover the area above the gas sensor body 30, the cage 40 of the second embodiment covers the area above the gas sensor body 30 as well. Furthermore, numerous ventilation holes 43 are formed through the roof portion 41 and the side wall portion 42 of the metal cage 40.

[0064] As a result, in the second embodiment, the air taken in from outside the housing 10 into the cavity space CA region within the partition wall 22 of the housing 10 is exposed to the surface temperature of the cage 40, which is heated by the heater 80 and has good thermal conductivity, as it passes through numerous ventilation holes 43 formed in the roof portion 41 and side wall portion 42 of the metal cage 40. Therefore, further thermal stabilization of the gas sensor body 30 and the air inside the cage 40 is achieved.

[0065] Furthermore, in the second embodiment, the metal cage 40, which is integrally combined with the copper surface portion 61 of the PCB substrate 60, also functions as a Faraday cage. In other words, the roof portion 41 and side wall portions 42 of the cage 40 surround the gas sensor body 30 on all sides, thereby protecting the gas sensor body 30 from radio wave interference / electromagnetic interference (EMI / RFI) from the surrounding environment and protecting the surrounding environment from electrical radiation from the gas sensor body 30 in all directions.

[0066] A Faraday cage refers to a space surrounded by conductors, or the cage or container made of conductors used to create such a space. Because electric field lines cannot penetrate the interior surrounded by conductors, the external electric field is blocked, and the potential inside becomes equal throughout.

[0067] As described above based on the embodiments and examples, the gas detection device according to one aspect of the present invention can improve the response speed of the gas sensor inside the housing. It should be noted that the gas detection device according to the present invention is not limited to the above embodiments or examples, and various modifications are possible without departing from the spirit of the present invention.

[0068] For example, in the above embodiment or example, a particle filter 24 for gas exchange is installed so as to cover the opening 23 of the compartment cover 20, and an inlet cover 50 is installed so as to cover the opening 23 from the opposite direction. However, the configuration of the gas inlet and outlet for the gas to be measured in a gas detection device according to one aspect of the present invention is not limited thereto, and various modifications are possible without departing from the spirit of the present invention.

[0069] For example, as shown in the first modified example in Figure 7, the inlet cover 50 may be attached so as to cover the opening 23 of the compartment cover 20 from the side. This configuration is suitable for preventing dust and raindrops from entering the opening 23 when the housing 10 is mounted vertically.

[0070] Furthermore, as shown in Figure 8, for example, a second modified example may be provided, which includes an inlet cover 50 that completely covers the opening 23 of the compartment cover 20 in the opposite direction, and an inlet pipe 51 for the gas to be measured and an outlet pipe 52 for the gas to be measured laid at two locations on the inlet cover 50. Such a configuration is suitable for preventing dust and raindrops from entering the opening 23, regardless of the mounting position of the housing 10. [Explanation of Symbols]

[0071] 10 cabinets 11 Base section 12 Cover section 13 Washers 14 Fixing bolts 15 Inserts 16 Fixing pins 17 O-rings 18 O-rings 19 O-rings 20 Compartment Covers 21 Mounting surface 22 Partition Wall 23 Opening 24-particle filter 30 Gas sensor unit 31-pin header 40 cages 41 Roof 42 Side wall 43 Air hole 50 Inlet cover 51 Cover fixing screws 60 PCB boards 61 Copper surface part 70 Insulating material 80 Heater 81 PID regulators 90 Other areas 100 Gas detection device CA Cavity Space

Claims

1. A device for detecting gases in the atmosphere, The system comprises a housing, a gas sensor body installed inside the housing, and a partition wall provided inside the housing that separates the gas sensor body from other areas, The partition wall defines a small cavity space around the gas sensor body. The housing and the partition wall are provided with openings that communicate directly with the cavity space from the outside but do not communicate with the cavity space and the other areas. A gas detection device characterized in that the volume of the cavity space is one-third or less of the volume of the other region.

2. The gas detection device according to Claim 1, wherein the length of the cavity space in the height direction, width direction, and depth direction is 2 times or less the length of the gas sensor body in the height direction, width direction, and depth direction, respectively.

3. The gas detection device according to claim 1 or claim 2, wherein the external shape of the housing is a rectangular parallelepiped.

4. The gas detection device according to any one of claims 1 to 3, further comprising an inlet cover that covers the opening.

5. Electronic components are arranged in the other areas of the housing. The gas detection device according to any one of claims 1 to 4, wherein only the cavity space is in communication with the outside through the opening.

6. The gas detection device according to any one of claims 1 to 5, further comprising a metal cage in the cavity space, which is arranged to surround the gas sensor body and is heated by a heater.

7. The gas detection device according to claim 6, wherein the cage has a plurality of ventilation holes.

8. The cage is soldered to the copper surface of the printed circuit board on which the gas sensor body is mounted. The gas detection device according to claim 6 or 7, which, when combined with the copper surface portion, also functions as a Faraday cage to protect the gas sensor body from radio wave interference / electromagnetic interference (EMI / RFI) from the surrounding environment.

Images