Cover for gas detector

Abstract

To enable improvements that accurately detect gas leaks using as few gas detectors as possible.SOLUTION: A cover for a gas detector mounted on a ceiling surface includes: a flat plate positioned along the ceiling surface and securing a gas detector; and a flange extending around the gas detector on the flat plate and sloping downward as it moves away from the gas detector. At least one of the flat plate and the flange is provided with a plurality of through holes, and the plurality of through holes are arranged to surround the gas detector.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed herein relates to a cover for a gas detector. [Background technology]

[0002] Patent Document 1 discloses a fuel cell vehicle in which a storage space for accommodating a fuel cell is provided below the passenger compartment of the vehicle. According to Patent Document 1, the storage space is covered by a ceiling surface formed by the bottom of the passenger compartment, and a hydrogen sensor is provided on the ceiling surface to detect the hydrogen concentration in the storage space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-73236 Summary of the Invention [Problem to be solved by the invention]

[0004] In fuel cell vehicles and other equipment equipped with fuel cells, hydrogen leakage is not limited to the fuel cell. Hydrogen can also leak from the nozzle of a hydrogen tank, the joints of various pipes, and other sources. However, installing a hydrogen detector at each and every potential hydrogen leakage point increases costs. Therefore, improvements are needed to accurately detect hydrogen leakage using as few hydrogen detectors as possible. Furthermore, these issues are not limited to hydrogen detection, but are also anticipated in various situations where gas detection is required. [Means for solving the problem]

[0005] This specification discloses a cover for a gas detector attached to a ceiling surface. The cover includes a flat plate portion that is disposed along the ceiling surface and to which the gas detector is fixed, and a flange portion that extends on the flat plate portion to surround the gas detector and slopes downward with increasing distance from the gas detector.

[0006] According to the above configuration, the cover includes the flange. Therefore, in the event of a gas leak in a space having the ceiling surface, the flange acts to keep the gas floating around the ceiling surface near the gas detector. As a result, the reliability of detection of leaked gas by a single gas detector can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] A simplified diagram showing a hydrogen detector installed on the ceiling of a space. [Figure 2] FIG. 2 is a view showing the cover according to the first embodiment as viewed from below. [Figure 3] Cross-sectional view taken along line III-III in Figure 2. [Figure 4] FIG. 10 is a view showing a cover according to a second embodiment as viewed from below. [Figure 5] FIG. 10 is a view showing a cover according to a third embodiment as viewed from below. [Figure 6] Cross-sectional view taken along line VI-VI in Figure 5. [Figure 7] FIG. 10 is a graph showing the change in hydrogen concentration over time. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present embodiment will be described with reference to the drawings. Each drawing is merely an example, and the present embodiment is not limited to the contents shown in the drawings. Also, since each drawing is an example, the shapes shown may not be accurate, and some parts may be omitted.

[0009] FIG. 1 shows a simplified view of a hydrogen detector 20 capable of detecting hydrogen attached to a ceiling surface 11 of a space 10. The hydrogen detector 20 is an example of a "gas detector." The following description will use the hydrogen detector 20 as an example of a gas detector. However, any detector or sensor capable of detecting gases or gases that are lighter than air and can be detected from the standpoint of ensuring safety, etc., falls under the category of gas detector envisioned in this embodiment.

[0010] Space 10 is a space from which the gas to be detected may leak. Ceiling surface 11 is not necessarily a horizontal surface, but in any case is a surface that defines the upper range of space 10. Space 10 may be a closed space or a partially open space. As an example, space 10 is a space provided under the floor of a passenger compartment of a fuel cell vehicle, and space 10 contains a fuel cell, a hydrogen tank, various pipes, etc.

[0011] 1 shows pipes 12 and 13 used to supply hydrogen gas 15, and a joint 14 connecting pipe 12 and pipe 13. Joint 14 is an example of a location that could be a source of leakage of hydrogen gas 15. Although not shown, it can be understood that there are multiple locations in space 10 that could be sources of such leakage. Space 10 is not limited to a space provided in a means of transportation such as a vehicle, but may also be a space provided in various facilities and buildings such as a factory, office, or home.

[0012] According to FIG. 1 , the hydrogen detector 20 is fixed to a cover 30, which is attached to the ceiling surface 11. In other words, when the hydrogen detector 20 is said to be attached to the ceiling surface 11, this includes both a case in which at least a portion of the hydrogen detector 20 is attached directly to the ceiling surface 11, and a case in which the hydrogen detector 20 is indirectly attached to the ceiling surface 11 via the cover 30 or the like. The cover 30 may also be referred to as a gas detector cover or the like. Various materials, such as metal and resin, are conceivable as materials for forming the cover 30. The cover 30 is formed from an appropriate material selected taking into consideration the environment in which the hydrogen detector 20 will be installed and the durability required of the cover 30. Although not shown, the hydrogen detector 20 is connected to cables buried in the ceiling or routed within the space 10 as necessary for communication and power supply.

[0013] The cover 30 according to the first embodiment will be described with reference to FIGS. FIG. 2 shows the cover 30 from a perspective below. FIG. 3 shows a cross-sectional view taken along line III-III in FIG. 2. According to the first embodiment, the cover 30 generally has a flat plate portion 31 and a flange portion 32. The flat plate portion 31 is disposed along the ceiling surface 11. The hydrogen detector 20 is fixed to the flat plate portion 31. "Along the ceiling surface 11" does not necessarily mean being parallel to the ceiling surface 11. As described above, the ceiling surface 11 is not necessarily a horizontal surface and may be curved. Therefore, the flat plate portion 31 only needs to be roughly along the ceiling surface 11, and may be inclined within a predetermined angle range with respect to the ceiling surface 11, for example.

[0014] The flat plate portion 31 may be fixed directly to the ceiling surface 11. However, according to the first embodiment, in consideration of the ease of installation, such as screwing, the flat plate portion 31 is fixed to the ceiling surface 11 via a support member 33. In other words, the support member 33 is fixed to the ceiling surface 11, and the flat plate portion 31 is fixed to the support member 33. The support member 33 is also referred to as a bracket or the like. By interposing the support member 33 between the ceiling surface 11 and the flat plate portion 31, the flat plate portion 31 is fixed at a position spaced a predetermined distance from the ceiling surface 11, for example, several centimeters downward. The shape of the support member 33 is not particularly important. Furthermore, in this embodiment, the method of fixing objects to each other is not particularly important.

[0015] According to the first embodiment, the flat plate portion 31 is square or rectangular and close to a square. The flat plate portion 31 may be entirely flat, or may be a member that includes at least a flat portion. The hydrogen detector 20 has a sensor portion 21 for detecting hydrogen, and a main body portion 22 that houses the circuits necessary to realize the functions of the sensor portion 21, communication functions, etc. The hydrogen detector 20 is fixed to the lower surface 31a of the flat plate portion 31 with the sensor portion 21 facing downward. At least the area of ​​the flat plate portion 31 to which the hydrogen detector 20 is fixed is flat.

[0016] A flange 32 extends from the flat plate portion 31 so as to surround the hydrogen detector 20. The flange 32 slopes downward as it moves away from the hydrogen detector 20. The flange 32 may also be referred to as a canopy portion or the like. According to the first embodiment, the flange 32 extends from each of the four edges of the flat plate portion 31, is connected as a whole, and surrounds the flat plate portion 31 and the hydrogen detector 20. Furthermore, the shape of the end (tip 32a) of the flange 32 opposite the end connected to the flat plate portion 31 is square or rectangular close to a square, similar to the flat plate portion 31.

[0017] 2, the hydrogen detector 20 and the cover 30 are arranged approximately concentrically with the hydrogen detector 20 at the center. Furthermore, as can be seen from Fig. 3, the tip 32a of the flange portion 32 is located farther from the ceiling surface 11 than the hydrogen detector 20. In other words, the tip 32a is located below the sensor portion 21 of the hydrogen detector 20.

[0018] Furthermore, a plurality of through holes 34 are provided in at least one of the flat plate portion 31 and the flange portion 32. According to the first embodiment, each through hole 34 is formed in a slit shape along each of the four sides of the flat plate portion 31, and these multiple through holes 34 are arranged to surround the hydrogen detector 20. The through holes 34 may also be simply referred to as slits. In FIG. 2, the through holes 34 are formed on the flange portion 32 side at the location where the flat plate portion 31 and the flange portion 32 are connected, but the through holes 34 may also be formed on the flat plate portion 31 side, or may be formed across the flat plate portion 31 and the flange portion 32. Of course, the number of through holes 34 is not limited to four as shown in the figure.

[0019] Furthermore, a wall portion 35 protruding downward is provided on the lower surface 31a of the flat plate portion 31. The wall portion 35 extends to surround the hydrogen detector 20. In FIG. 2, the wall portion 35 surrounds the periphery of the hydrogen detector 20 without interruption, but the continuity of the wall portion 35 may be partially interrupted around the periphery of the hydrogen detector 20. According to FIG. 3, the wall portion 35 does not protrude downward beyond the tip 32a of the flange portion 32. Furthermore, the wall portion 35 is provided between the hydrogen detector 20 and the through-holes 34. However, the wall portion 35 may be located outward with respect to the hydrogen detector 20 relative to at least some of the through-holes 34. Furthermore, the wall portion 35 may be provided on the lower surface of the flange portion 32.

[0020] A cover 30 according to a second embodiment will be described with reference to FIG. 4. Like FIG. 2, FIG. 4 shows the cover 30 from a perspective from below. For the second embodiment, only the differences from the first embodiment will be described. As with the first embodiment, a cross-sectional view of the second embodiment can be seen in FIG. 3. As shown in FIG. 4, according to the second embodiment, the flat plate portion 31 and the flange portion 32 extending from the edge of the flat plate portion 31 are circular. In other words, the shape of the cover 30 when viewed from below may be circular.

[0021] In the second embodiment, each of the multiple through holes 34 is a slit that curves along the curved edge of the flat plate portion 31, and the circle formed by connecting the multiple through holes 34 is concentric with the hydrogen detector 20 at its center, similar to the flat plate portion 31 and the flange portion 32. Furthermore, as shown in Figure 4, the wall portion 35 surrounding the hydrogen detector 20 is also concentric with the hydrogen detector 20 at its center.

[0022] A cover 30 according to a third embodiment will be described with reference to FIGS. 5 and 6. Like FIGS. 2 and 4, FIG. 5 shows the cover 30 from a perspective from below. FIG. 6 shows a cross-sectional view taken along line VI-VI in FIG. 5. Regarding the third embodiment, only the differences from the first embodiment will be described. According to the third embodiment, a through-hole 31b of a size that does not allow the main body 22 of the hydrogen detector 20 to pass through is formed in the center of the flat plate portion 31. The main body 22 is fixed above the flat plate portion 31, i.e., in the space between the flat plate portion 31 and the ceiling surface 11.

[0023] The through-hole 31b is formed to a size that allows the sensor portion 21 of the hydrogen detector 20 to pass through, and the sensor portion 21 protrudes downward from the lower surface 31a through the through-hole 31b and faces downward. The support member 33 is shaped so as not to interfere with the main body portion 22 that is housed in the space between the flat plate portion 31 and the ceiling surface 11. Alternatively, the support member 33 and the main body portion 22 may be partially in contact with or connected to each other.

[0024] In the third embodiment, the hydrogen detector 20 is positioned closer to the ceiling surface 11 than in the first and second embodiments. The closer the hydrogen detector 20 is to the ceiling surface 11, the more advantageous it is for detecting hydrogen. It goes without saying that in the third embodiment, the cover 30 may also have a circular shape as shown in the second embodiment.

[0025] Thus, according to this embodiment, the cover 30 for a gas detector (e.g., hydrogen detector 20) attached to the ceiling surface 11 is arranged along the ceiling surface 11 and comprises a flat plate portion 31 to which the gas detector is fixed, and a flange portion 32 that extends to surround the gas detector on the flat plate portion 31 and slopes downward as it moves away from the gas detector. 1, if a leak of hydrogen gas 15 occurs in space 10, the hydrogen gas 15 floating around ceiling surface 11 can be confined near hydrogen detector 20 by the action of flange 32 of cover 30. This stabilizes the hydrogen concentration near hydrogen detector 20, improving the reliability of detection of leaked hydrogen gas 15 by a single hydrogen detector 20.

[0026] Furthermore, according to this embodiment, at least one of the flat plate portion 31 and the flange portion 32 may have a plurality of through holes 34, and the plurality of through holes 34 may be arranged so as to surround the gas detector. According to the above configuration, even if the installation position of the hydrogen detector 20 is not directly above the leak position of the hydrogen gas 15 (for example, the joint 14), the cover 30 allows the hydrogen gas 15, which sprays out from the leak position and then moves and diffuses along the ceiling surface 11, to enter the inside of the cover 30 from various directions through each of the through-holes 34. This stabilizes the hydrogen concentration inside the cover 30, i.e., in the vicinity of the hydrogen detector 20, and further increases the reliability of detection by the hydrogen detector 20.

[0027] Furthermore, according to this embodiment, a wall portion 35 may be provided on the lower surface of the flat plate portion 31, protruding downward and extending so as to surround the gas detector. According to the above configuration, the wall portion 35 surrounding the hydrogen detector 20 acts to further enhance the effect of confining the hydrogen gas 15 near the hydrogen detector 20 and stabilizing the hydrogen concentration near the hydrogen detector 20.

[0028] The inclination angle θ of the flange portion 32 relative to the flat plate portion 31 (see FIG. 3) may be, for example, 30 to 60 degrees. If the inclination angle θ is too small, the cover 30 will not be effective in retaining the hydrogen gas 15 near the hydrogen detector 20, while if the inclination angle θ is too large, hydrogen gas 15 that leaks at a position other than directly below the hydrogen detector 20 will not be able to be efficiently guided inside the cover 30. Therefore, the range of 30 to 60 degrees can be said to be an example of an appropriate range for the inclination angle θ.

[0029] Furthermore, according to this embodiment, the tip 32a of the flange portion 32 may be positioned farther from the ceiling surface 11 than the gas detector. According to the above configuration, the tip 32a of the flange 32 is located below the hydrogen detector 20. Therefore, the flange 32 can prevent the hydrogen gas 15 that accumulates near the hydrogen detector 20 from leaking out of the cover 30.

[0030] The hydrogen detector 20 is capable of detecting hydrogen at a predetermined concentration, for example, 4% or more. After leaking into the space 10, the hydrogen gas 15 rises and then diffuses in a meandering pattern up and down and left and right as it moves along the ceiling surface 11. The hydrogen concentration decreases the further downward from the ceiling surface 11 the gas moves.

[0031] 7 is a graph showing the change in hydrogen concentration over time in the vicinity of a hydrogen detector 20 that is located at a predetermined position that is not directly above the leak location of hydrogen gas 15 but is a predetermined number of centimeters below the ceiling surface 11. In FIG. 7, the solid line graph shows the hydrogen concentration in the vicinity of the hydrogen detector 20 that is located at the predetermined position and has the cover 30 of the first embodiment. On the other hand, in FIG. 7, the two-dot chain line graph shows the hydrogen concentration in the vicinity of the hydrogen detector 20 that is located at the predetermined position and does not have the cover 30. The hydrogen concentrations shown in FIG. 7 can be interpreted as concentrations obtained by using a specific detector other than the hydrogen detector 20 that has higher detection capabilities than the hydrogen detector 20 for the experiment.

[0032] As can be seen from FIG. 7 , in the configuration without the cover 30, the hydrogen concentration fluctuated significantly and was often below 4%. On the other hand, in the configuration with the cover 30, the hydrogen concentration remained nearly stable at 4% or higher. Therefore, in the conventional configuration without the cover 30, even if a leak of hydrogen gas 15 occurred, the hydrogen concentration was unstable near the hydrogen detector 20 that was not located directly above the leak location, and the hydrogen detector 20 was unable to detect hydrogen. In contrast, in this embodiment, the effect of the cover 30 makes it easier for the hydrogen concentration near the hydrogen detector 20 to stabilize at a predetermined concentration or higher. Therefore, it is possible to minimize situations in which the hydrogen detector 20 is unable to detect hydrogen despite a leak of hydrogen gas 15 occurring somewhere in the space 10. As such, in this embodiment, the hydrogen detector 20 can detect hydrogen with high reliability, allowing a single hydrogen detector 20 to detect hydrogen over a wide area, thereby reducing the number of hydrogen detectors 20 required and contributing to cost reduction.

[0033] The following is a supplementary explanation of the shape of the cover 30. According to each drawing, the flange portion 32 extends downward and away from the edge of the flat plate portion 31. However, the flange portion 32 may extend from a position on the flat plate portion 31 that is closer to the hydrogen detector 20 than the edge of the flat plate portion 31.

[0034] Furthermore, the position where the flange portion 32 connects to the flat plate portion 31 may be so close that there is almost no distance between it and the periphery of the hydrogen detector 20. In other words, the flat plate portion 31 may have the same size as the hydrogen detector 20 as the minimum size required to fix the hydrogen detector 20, and the flange portion 32 may be connected to the periphery of a flat plate portion 31 of this size. The shape of the cover 30 when viewed from below is not limited to the shape shown in the drawings, and various shapes may be used, such as an ellipse or a polygon other than a rectangle.

[0035] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of those objectives itself has technical utility. [Explanation of symbols]

[0036] 10: Space, 11: Ceiling surface, 12, 13: Piping, 14: Joint, 15: Hydrogen gas, 20: Hydrogen detector, 21: Sensor section, 22: Main body section, 30: Cover, 31: Flat plate section, 31a: Underside, 31b: Through hole, 32: Collar section, 32a: Tip, 33: Support member, 34: Through hole, 35: Wall section

Claims

1. A cover for a gas detector attached to a ceiling surface, a flat plate portion that is disposed along the ceiling surface and to which the gas detector is fixed; a flange portion that extends to surround the gas detector at the flat portion and slopes downward as it moves away from the gas detector;

2. At least one of the flat plate portion and the flange portion is provided with a plurality of through holes, The cover according to claim 1 , wherein the plurality of through-holes are arranged to surround the gas detector.

3. 2. The cover according to claim 1, wherein a wall portion is provided on the lower surface of the flat plate portion, the wall portion protruding downward and extending so as to surround the gas detector.

4. 2. The cover according to claim 1, wherein the flange portion is inclined at an angle of 30 to 60 degrees relative to the flat plate portion.

5. The cover according to claim 1 , wherein a tip of the flange portion is positioned farther from the ceiling surface than the gas detector.

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