Tunnel board

Abstract

To provide a tunnel board capable of reducing the pressure difference between the inside and outside of a housing without changing the volume inside the housing even when a pressure difference occurs between the inside and outside of the housing.SOLUTION: A tunnel board 100 is installed inside a tunnel, and includes a housing 1, a first ventilation opening 2 and a second ventilation opening 3 leading to the inside of the housing 1, a filter 4 covering the first ventilation opening 2, and a door body 5 that closes the second ventilation opening 3 in an openable and closable manner, and the door body 5 is configured to open the second ventilation opening 3 when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a panel for a tunnel.

Background Art

[0002] Patent Document 1 discloses a conventional panel device. The panel device described in Patent Document 1 is installed in a tunnel through which a vehicle passes. When a vehicle passes through the tunnel, the surrounding of the outside of the housing of the panel device becomes negative pressure due to the air pressure wave generated, and the inside of the housing becomes relatively positive pressure, resulting in a pressure difference between the inside and outside of the housing.

[0003] Therefore, the panel device of Patent Document 1 includes a filter-mounted member equipped with a filter and a shielding member having a telescopic bellows structure. When the pressure inside the housing becomes positive pressure relative to the outside of the housing, the bellows structure extends to increase the volume inside the housing and reduce the pressure inside the housing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the panel device of Patent Document 1 has a problem in that when the pressure inside the housing becomes positive pressure relative to the outside of the housing, it needs to be deformed to increase the volume of the housing, so it is necessary to consider the installation space in consideration of the shape of the bellows structure after deformation.

[0006] In view of the above circumstances, the present invention has been made, and an object thereof is to provide a tunnel panel that can relieve the pressure difference between the inside and outside of the housing without changing the volume inside the housing even when a pressure difference occurs between the inside and outside of the housing.

Means for Solving the Problems

[0007] A tunnel panel according to one aspect of the present invention is a tunnel panel installed in a tunnel, comprising a housing, a first vent and a second vent leading into the housing, a filter covering the first vent, and a door that can open and close the second vent, wherein the door is configured to open the second vent when the pressure inside the housing becomes positive compared to the pressure outside the housing. [Effects of the Invention]

[0008] The tunnel panel according to the above embodiment of the present invention has the advantage that even if a pressure difference occurs inside and outside the enclosure, the pressure difference between the inside and outside the enclosure can be mitigated without changing the volume inside the enclosure. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1(A) is a schematic perspective view of the tunnel panel according to this embodiment. Figure 1(B) is a cross-sectional view of the tunnel panel according to this embodiment in a vertical plane around the first and second ventilation openings. [Figure 2] Figure 2(A) is a cross-sectional view of the tunnel panel according to this embodiment when the door body is in the open position. Figure 2(B) is a cross-sectional view of the tunnel panel according to this embodiment when the door body is in the closed position. [Figure 3] Figure 3(A) is a cross-sectional view of the tunnel panel according to the first modification in a vertical plane around the first and second ventilation openings. Figure 3(B) is a cross-sectional view of the tunnel panel according to the first modification when the door body is in the open position. Figure 3(C) is a cross-sectional view of the tunnel panel according to the first modification when the door body is in the closed position. [Figure 4] Figure 4(A) is a cross-sectional view of the tunnel panel according to the second modified example, when the door body is in the open position. Figure 4(B) is a cross-sectional view of the tunnel panel according to the second modified example, when the door body is in the closed position. [Figure 5] Figure 5(A) is a cross-sectional view of the tunnel panel according to the third modified example, with the door in the open position. Figure 5(B) is a cross-sectional view of the tunnel panel according to the third modified example, with the door in the closed position. [Figure 6] Figure 6(A) is a cross-sectional view of the tunnel panel according to the fourth modified example, when the door body is in the open position. Figure 6(B) is a cross-sectional view of the tunnel panel according to the fourth modified example, when the door body is in the closed position. [Modes for carrying out the invention]

[0010] <Embodiment> The tunnel panel 100 is a panel installed inside a tunnel. As shown in Figure 1, the tunnel panel 100 comprises a housing 1, a first ventilation opening 2 and a second ventilation opening 3 leading into the housing 1, a filter 4 covering the first ventilation opening 2, and a door body 5 that can open and close the second ventilation opening 3. The door body 5 is configured to open the second ventilation opening 3 when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1.

[0011] With this configuration, when a vehicle moves through the tunnel, for example, when the vehicle passes near the tunnel panel 100, a temporary pressure fluctuation occurs around the tunnel panel 100, causing the air pressure outside the housing 1 to drop temporarily. At this time, the second vent 3 opens, allowing air to flow from inside the housing 1 to outside, reducing the pressure difference between the inside and outside of the housing 1. After the vehicle has passed near the tunnel panel 100, the air pressure around the tunnel panel 100 rapidly recovers from the reduced pressure to its original pressure. At this time, the inside of the housing 1 becomes negative pressure compared to the outside of the housing 1, causing the second vent 3 to close. As a result, air from outside the housing 1 passes through the filter 4 and flows into the housing 1, reducing the pressure difference between the inside and outside of the housing 1.

[0012] Thus, in the tunnel panel 100 according to this embodiment, when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1, the second vent 3 opens to reduce the pressure difference between the inside and outside of the housing 1. However, even when the second vent 3 is open, the airflow from inside to outside the housing 1 reduces the intrusion of dust through the second vent 3. Furthermore, when the pressure inside the housing 1 becomes negative compared to the pressure outside the housing 1, air flows in through the filter 4, thus reducing the intrusion of dust. As a result, according to the tunnel panel 100 according to this embodiment, even if pressure fluctuations occur in the tunnel, the pressure difference between the inside and outside of the housing 1 can be reduced without changing the volume of the housing 1, while reducing the intrusion of dust into the housing 1.

[0013] Examples of tunnel panels 100 include a power distribution panel 10 included in a switchgear, a switchboard, a circuit breaker panel, a disaster prevention receiving panel, a control panel, a relay amplifier panel, etc. In this embodiment, a power distribution panel 10 in which power equipment is housed in a housing 1 will be described as the tunnel panel 100.

[0014] In the following, for the sake of explanation, the direction along the horizontal plane and extending from the inside to the outside of the enclosure 1 will be referred to as the "outward direction," the opposite direction as the "inward direction," and the direction parallel to both the outward and inward directions as the "inward-outward direction."

[0015] Furthermore, in this specification, "parallel" includes not only cases where two lines, planes, etc. (hereinafter referred to as "lines, etc.") do not intersect when extended, but also cases where the angles formed by the two lines, etc. intersect within a range of 10° or less. Also, "orthogonal" means cases where two lines, etc. intersect within a range of 90° ± 10°. However, even if two lines, etc. do not directly intersect, they are included in "orthogonal" if they intersect when extended.

[0016] (power equipment) Power equipment is equipment that operates by receiving an electric power supply. There are no particular restrictions on what constitutes power equipment; examples include circuit breakers, switches, disconnectors, grounding switches, instrument transformers, and transformers.

[0017] (Enclosure 1) Fig. 1(A) is a schematic perspective view of the switchboard 10 as seen from the front side. The housing 1 is a box-shaped body having a front panel 14, a rear panel 15, a pair of side plates 11, a top plate 12, and a bottom plate 13. Examples of the material of the housing 1 include metals.

[0018] In the housing 1, a first ventilation port 2 and a second ventilation port 3 are formed. The first ventilation port 2 is a through-hole where the filter 4 is installed, and the second ventilation port 3 is a through-hole where the door body 5 is installed. The first ventilation port 2 and the second ventilation port 3 are preferably formed on the front panel 14. However, the first ventilation port 2 and the second ventilation port 3 may be formed on the side plate 11 or the rear panel 15 as long as they are not facing obstacles such as wall surfaces.

[0019] The first ventilation port 2 and the second ventilation port 3 are preferably formed at the lower part of the housing 1. The lower part of the housing 1 means the part below the center in the height direction of the housing 1. By forming the first ventilation port 2 and the second ventilation port 3 at the lower part of the housing 1, even if dust enters through the first ventilation port 2 or the second ventilation port 3, it is easy to drop the dust to the bottom of the housing 1, and the possibility that the electrical equipment in the housing 1 is soiled by the dust can be reduced.

[0020] The second ventilation port 3 is preferably formed below the first ventilation port 2. Thereby, it is easy to drop the dust that has entered through the second ventilation port 3 where no filter is provided to the bottom of the housing 1. However, the second ventilation port 3 may be formed above the first ventilation port 2. Also, the first ventilation port 2 and the second ventilation port 3 do not have to be formed on the same plate. For example, the first ventilation port 2 may be formed on the front panel 14 and the second ventilation port 3 may be formed on the side plate. Also, the first ventilation port 2 and the second ventilation port 3 may be formed side by side.

[0021] The first vent 2 and the second vent 3 are preferably formed in an elongated rectangular shape extending along a horizontal plane. However, the shapes of the first vent 2 and the second vent 3 may be, for example, circular, elliptical, square, semicircular, rhombus, etc. Also, the first vent 2 and the second vent 3 may be composed of multiple holes. The shape of the vents 2 and 3 should be selected according to the required strength of the housing 1.

[0022] Furthermore, the first vent 2 and the second vent 3 may be covered with a cover member having numerous through-holes, such as a louver, perforated metal, expanded metal, or wire mesh. Examples of through-hole shapes include round, slotted, polygonal, and slit shapes. The maximum inner diameter of the through-hole is slightly larger than the maximum hole diameter of the filter 4. When a louver is used as the cover member, examples of louvers include H-shaped, V-shaped, perforated, mesh, single-slope, and V-shaped louvers.

[0023] (Filter 4) The filter 4 is positioned to cover the first vent 2. The filter 4 is a dust filter capable of capturing fine particles (dust) contained in the air. Preferably, the filter 4 is capable of capturing fine particles with a particle size of 5 μm or larger. Examples of fine particles captured by the filter 4 include dust, dirt, and powder with relatively large particle sizes (hereinafter referred to as "dust"; in this specification, "dust" also includes "dirt"). The shape of the filter 4 may be, for example, a flat plate or a pleated shape. The filter 4 may be single-layered or multi-layered.

[0024] As shown in Figure 1(B), the filter 4 is mounted along the inner surface of the front panel 14 of the housing 1. Preferably, the filter 4 is removably held by a mounting portion 41 provided on the inner surface of the housing 1. The mounting portion 41 is formed in a substantially rectangular frame shape when viewed from the front and holds the outer periphery of the filter 4. Note that the mounting of the filter 4 is not limited to the mounting portion 41, and may be achieved by, for example, adhesive, screw fastening, clamping, etc. The filter 4 may also be mounted along the outer surface of the housing 1.

[0025] (Door panel 5) The door 5 is attached to the housing 1 so that it can close the second ventilation opening 3. The door 5 can be switched between an open position (see Figure 2(A)) that opens the second ventilation opening 3 and a closed position (see Figure 2(B)) that closes the second ventilation opening 3. The basic position of the door 5 is the closed position, but when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1, the door 5 is switched to the open position.

[0026] In this embodiment, the door body 5 is provided with a pivot shaft 51 at its upper end. The pivot shaft 51 extends along the horizontal plane. The door body 5 is attached to the front panel 14, for example, via a hinge having the pivot shaft 51. When an external force is applied to the door body 5 in the outward direction, the lower end rotates around the pivot shaft 51 away from the housing 1, switching from the closed position to the open position, and when the external force is released, it switches back to the closed position.

[0027] The tunnel panel 100 may have a spring that applies force to the door body 5 from the open position to the closed position. This makes it easier to position the door body 5 in the closed position when no force is being applied to the door body 5 toward the open position. Examples of the spring include a torsion spring. However, if the door body 5 can be sufficiently positioned in the closed position by its own weight, a spring may not be necessary.

[0028] The door body 5 is, for example, in the shape of a plate. There are no particular restrictions on the material of the door body 5, and examples include metal, synthetic resin, glass, carbon, wood, pulp, etc.

[0029] As shown in Figure 2(A), when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1, air pressure is evenly distributed across the filter 4 and the door 5. However, due to the air resistance of the filter 4, the door 5 is more likely to open before air can pass through the filter 4. Therefore, when the door 5 is switched to the open position, the second vent 3 allows air to flow from the inside to the outside of the housing 1, and the air inside the housing 1 passes through the second vent 3 and is discharged to the outside of the housing 1.

[0030] As shown in Figure 2(B), when the internal pressure of the housing 1 becomes negative compared to the external pressure, air from outside the housing 1 enters the housing 1 through the first vent 2 and filter 4. At this time, the door 5, which is in the closed position, blocks the air attempting to pass through the second vent 3.

[0031] As described above, in the tunnel panel 100 according to this embodiment, when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1, the second vent 3 opens to reduce the pressure difference between the inside and outside of the housing 1. However, even when the second vent 3 is open, the airflow from inside to outside the housing 1 reduces the intrusion of dust through the second vent 3. Furthermore, when the pressure inside the housing 1 becomes negative compared to the pressure outside the housing 1, air flows in through the filter 4, thus reducing the intrusion of dust. As a result, according to the tunnel panel 100 according to this embodiment, even if pressure fluctuations occur in the tunnel, the pressure difference between the inside and outside of the housing 1 can be reduced while reducing the intrusion of dust into the housing 1.

[0032] It is preferable to design the opening areas of the first vent 2 and the second vent 3 so that the pressure difference between the inside and outside of the housing 1 is constantly suppressed to below a predetermined pressure. Here, "below a predetermined pressure" is preferably 5 kPa or less, and more preferably 2 kPa or less. This allows the strength of the housing 1 to be underestimated and designed accordingly, and for example, the reinforcing structure of the housing 1 can be simplified.

[0033] <Variation> The above embodiments are merely one of many embodiments of the present invention. The embodiments can be modified in various ways depending on the design, etc., as long as the objectives of the present invention are achieved. The following lists some modifications of the embodiments. The modifications described below can be combined and applied as appropriate.

[0034] (First variation) In the above embodiment, the first vent 2 is formed in the housing 1, but as shown in Figure 3, the first vent 2 may be formed in the door body 5. As shown in Figure 3, the first vent 2 is formed so as to penetrate the door body 5. The filter 4 is held so as to cover the first vent 2. The filter 4 is held in place by the door body 5 by a mounting portion 41 provided on the opening periphery of the door body 5.

[0035] As shown in Figure 3(B), when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1, air pressure is evenly distributed across the filter 4 and the door 5. However, the air resistance of the filter 4 causes the door 5 to open before the air can pass through the filter 4. Therefore, when the door 5 is switched to the open position, the second vent 3 allows air to flow from the inside to the outside of the housing 1, and the air inside the housing 1 passes through the second vent 3 and is discharged to the outside of the housing 1.

[0036] As shown in Figure 3(C), when the internal pressure of the housing 1 becomes negative compared to the external pressure, air from outside the housing 1 enters the housing 1 through the first vent 2 and filter 4. At this time, the door 5, which is in the closed position, blocks any air attempting to pass through the second vent 3 other than the air passing through the first vent 2.

[0037] With this configuration, only one opening (second ventilation opening 3) needs to be machined into the enclosure 1. This makes it easier to carry out additional work on existing tunnel panels 100, for example, by pre-fabricating a door body 5 having the first ventilation opening 2 in the factory.

[0038] (Second variation) In the above embodiment and the first modified example, when the door body 5 is opened, if the door body 5 moves too forcefully, it may open too far and not return to the closed position. However, in the second modified example, by having a stopper 6 that restricts the degree to which the door body 5 opens, it is possible to prevent the door body 5 from opening too far.

[0039] In this modified example, the stopper 6 is an elastic body 61 that connects the housing 1 and the door body 5. The housing 1 has a support member 31 positioned to overlap with the second vent 3 in a front view. The support member 31 is fixed to the peripheral edge of the opening of the second vent 3 and protrudes into the second vent 3 in a front view. The elastic body 61 connects the support member 31 and the door body 5 and restricts the degree to which the door body 5 opens. Examples of the elastic body 61 include a torsion coil spring and rubber.

[0040] The maximum opening angle of the door body 5 is preferably 60° or less, more preferably 45° or less, and even more preferably less than 30° with respect to the vertical plane.

[0041] This prevents the door body 5 from opening too far, thus reducing the likelihood of it opening too far and failing to return to the closed position, even if the door body 5 moves forcefully when opening.

[0042] (Third variation) The stopper 6 may be a rotation restricting portion 62 that comes into contact with a part of the door body 5 when the door body 5 is opened, as shown in Figure 5(A). The rotation restricting portion 62 comprises a horizontal piece 621 protruding from the housing 1 and a vertical piece 622 protruding downward from the horizontal piece 621. In a front view, the vertical piece 622 overlaps the door body 5. The horizontal piece 621 and the vertical piece 622 are made of metal, for example.

[0043] When the door 5 opens, it hits the vertical piece 622, preventing it from opening any further. In other words, the position where the door 5 hits the vertical piece 622 is the open position of the door 5. The position of the lower end of the vertical piece 622 is set according to the maximum opening degree of the door 5.

[0044] The rotation restricting section 62 is composed of a horizontal piece 621 and a vertical piece 622, but it may also be composed of, for example, a string, belt, chain, wire, etc., attached to connect the door body 5 and the housing 1.

[0045] (Fourth variation) When the pressure inside the housing 1 becomes negative compared to the pressure outside the housing 1, the door body 5 is switched to the closed position. At this time, in order to improve the responsiveness of the movement of the door body 5, the housing 1 may have a flow path guide 7, as in this modified example. The flow path guide 7 can guide the airflow flowing from outside the housing 1 into the housing 1 to the outer surface of the door body 5. As shown in Figure 6, the flow path guide 7 comprises a horizontal plate portion 71 protruding from the outer surface of the housing 1 and a vertical plate portion 72 protruding upward from the horizontal plate portion 71. Preferably, the upper end of the vertical plate portion 72 is located above the upper end of the second vent 3.

[0046] The air flowing from outside the enclosure 1 toward the second vent 3 is guided by the flow path guide 7 and strikes the outer surface of the door body 5. As a result, the door body 5 is subjected to pressure from the air in addition to its own weight, causing it to rotate faster than it would under its own weight alone.

[0047] Preferably, the vertical plate portion 72 is formed at a position where it will come into contact with the door body 5 when the door body 5 is switched to the open position. This allows it to also serve the function of the stopper 6 described in the second and third modified examples.

[0048] (Other variations) In the above embodiment, the pivot axis 51 of the door body 5 is provided at the upper end of the door body 5, but it may be provided at the lower end or located in the center in the vertical direction. Furthermore, the door body 5 may have pivot axes 51 extending vertically at its left and right ends. Also, the structure may allow the two door bodies 5 to open and close like double doors.

[0049] In the above embodiment, the door body 5 was switched between the open and closed positions by rotating around the pivot axis 51. However, the door body 5 may also be switched between the open and closed positions by translating it in a direction perpendicular to the opening surface of the second ventilation opening 3.

[0050] In the above embodiment, a part of the front plate 14 was interposed between the first vent 2 and the second vent 3, but the first vent 2 and the second vent 3 may be connected. In other words, the first vent 2 and the second vent 3 may be formed by a single opening.

[0051] The distribution panel 10 may be any of the following: a secondary transformer panel, a busbar connection panel, a receiving panel, a distribution line panel, a primary transformer panel, an in-house transformer panel, a VCT panel, etc.

[0052] Vehicles passing through the tunnel can be railway vehicles (electric trains, magnetic levitation trains) or automobiles, as long as they generate pressure fluctuations exceeding several kPa within the tunnel.

[0053] <Summary> As described above, the tunnel panel 100 according to the first embodiment is a tunnel panel 100 installed inside a tunnel, comprising a housing 1, a first ventilation opening 2 and a second ventilation opening 3 leading into the housing 1, a filter 4 covering the first ventilation opening 2, and a door body 5 that can open and close the second ventilation opening 3. The door body 5 is configured to open the second ventilation opening 3 when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1.

[0054] In this configuration, when a vehicle moves through a tunnel, for example, when the vehicle passes near the tunnel panel 100, a temporary pressure fluctuation occurs around the tunnel panel 100, causing the air pressure outside the housing 1 to drop temporarily. At this time, the second vent 3 opens, allowing air to flow from inside the housing 1 to outside, reducing the pressure difference between the inside and outside of the housing 1. After the vehicle has passed near the tunnel panel 100, the air pressure around the tunnel panel 100 rapidly recovers from the reduced pressure to its original pressure. At this time, the inside of the housing 1 becomes a negative pressure compared to the outside of the housing 1, causing the second vent 3 to close. As a result, air from outside the housing 1 passes through the filter 4 and flows into the housing 1, reducing the pressure difference between the inside and outside of the housing 1. Thus, in the tunnel panel 100, when the pressure inside the housing 1 becomes positive compared to the pressure outside the housing 1, the second vent 3 opens to reduce the pressure difference between the inside and outside of the housing 1. However, even when the second vent 3 is open, the airflow from inside to outside the housing 1 reduces the intrusion of dust through the second vent 3. Furthermore, when the pressure inside the housing 1 becomes negative compared to the pressure outside the housing 1, air flows in through the filter 4, thus reducing the intrusion of dust. As a result, according to the tunnel panel 100 of this embodiment, even if pressure fluctuations occur in the tunnel, the pressure difference between the inside and outside of the housing 1 can be reduced without changing the volume of the housing 1, while reducing the intrusion of dust into the housing 1.

[0055] In the tunnel panel 100 according to the second embodiment, the first vent 2 is formed above the second vent 3, as in the first embodiment. According to this embodiment, dust that enters through the second vent 3, which is not provided with a filter 4, is more easily dropped to the bottom of the housing 1.

[0056] In the tunnel panel 100 according to the third embodiment, the first ventilation opening 2 and the filter 4 are formed in the door body 5, as in the first embodiment. According to this embodiment, only one opening (second ventilation opening 3) needs to be processed in the housing 1, resulting in good manufacturability.

[0057] In the tunnel panel 100 according to the fourth embodiment, in any of the first to third embodiments, the door body 5 is rotatably mounted to the housing 1 on a pivot axis 51 whose upper end is aligned horizontally, and the door body 5 is configured to open when the lower end of the door body 5 separates from the housing 1. The housing 1 has a stopper 6 that restricts the degree to which the door body 5 opens. In this embodiment, the door body 5 is prevented from opening too far, so that even if the door body 5 moves forcefully when opening, the problem of it opening too far and not returning to the closed position is reduced.

[0058] In the tunnel panel 100 according to the fifth embodiment, the stopper 6 is an elastic body 61 that connects the housing 1 and the door body 5, as in the fourth embodiment. According to this embodiment, the occurrence of collision noise when the door body 5 is opened is suppressed.

[0059] In the tunnel panel 100 according to the sixth embodiment, the stopper 6 is a rotation restricting part 62 that strikes the door when the door body 5 is opened, as in the fourth embodiment. According to this embodiment, the rotation of the door body 5 can be reliably restricted when the door body 5 is opened.

[0060] In the tunnel panel 100 according to the seventh embodiment, in any of the first to sixth embodiments, the housing 1 has a flow path guide 7 that guides the airflow flowing from the outside to the inside of the housing 1 to the outer surface of the door body 5. According to this embodiment, the air flowing from outside the housing 1 toward the second vent 3 is guided by the flow path guide 7 and strikes the outer surface of the door body 5. As a result, the door body 5 is subjected to a force from the air in addition to its own weight, causing it to rotate faster than it would by its own weight alone. This improves the responsiveness of the door body 5's movement from the open position to the closed position. [Explanation of Symbols]

[0061] 100 Tunnel Panel 10 Switchboard 1 cabinet 2. First ventilation opening 3. Second ventilation opening 4 filters 5 Door Body 51 Rotation axis 6 Stopper 61 Elastic body 62 Rotation regulating section 7 Flow path guide

Claims

1. A tunnel panel installed inside a tunnel, The casing and The first ventilation opening and the second ventilation opening that lead to the inside of the housing, A filter covering the first vent, A door body that can open and close the second ventilation opening, Equipped with, The door is configured to open the second vent when the pressure inside the housing becomes positive compared to the pressure outside the housing, and by opening the second vent, air flows from inside the housing to outside the housing. Tunnel board.

2. The second vent is formed below the first vent. The tunnel panel according to claim 1.

3. The first vent and the filter are formed in the door body. The tunnel panel according to claim 1.

4. The door body is mounted to the housing so that its upper end is rotatable on a pivot axis that is aligned horizontally, and the door body opens when its lower end separates from the housing. The housing has a stopper that restricts the degree to which the door body opens. The tunnel panel according to any one of claims 1 to 3.

5. The stopper is an elastic body that connects the housing and the door body. The tunnel panel according to claim 4.

6. The stopper is a rotation restricting part that comes into contact with the door when the door is opened. The tunnel panel according to claim 4.

7. The housing has a flow path guide that directs the airflow flowing from the outside to the inside of the housing to the outer surface of the door body. The tunnel panel according to any one of claims 1 to 3.

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