Dust protection housing for a smoke detector, smoke detector arrangement and flow channel

Abstract

A housing (30) for a smoke detector (22) contains a central axis (32) perpendicular to a flow plane (12) of air (4), an interior space (34) with a mounting area (36) for the smoke detector (22), an opening (38) through which the central axis (32) passes parallel to the flow plane (12), and a grid structure (46) in the opening (38) with at least two crossed grid components (48) running flatly parallel to the central axis (32). A smoke detector assembly (20) contains the housing (30) and the smoke detector (22) in the mounting area (36) in the interior (34). A flow channel (2) contains the housing (30) and has the flow plane (12) for the air (4) at the location of the housing (30), the central axis (32) being aligned perpendicular to the flow plane (12).

Description

[0001] The invention relates to a smoke detector, a smoke detector arrangement and a flow channel.

[0002] A problem with certain smoke detectors, especially optical ones, is their interference with dust. This particularly affects smoke detectors installed in vehicle air conditioning / ventilation ducts. There, they are exposed to the air flowing in the duct and the dust it carries, and they become dusty particularly quickly.

[0003] A smoke detection device for an air conditioning duct is known from DE 10 2022 116 715 A1. This device comprises an optical smoke detector with a smoke cap for optically detecting penetrating smoke particles and a closed enclosure around at least the smoke cap of the optical smoke detector. The enclosure has an inlet diffuser on its front side facing the air conditioning flow in the air conditioning duct and one or more outlet openings on its rear side facing away from the air conditioning flow in the air conditioning duct and / or on its bottom. Dust particles from the air conditioning flow flow into the enclosure, but flow out of the enclosure again without contacting the smoke cap of the optical smoke detector. The smaller smoke particles pass through the inlet diffuser to the smoke cap of the optical smoke detector.

[0004] A method for detecting smoke particles is known from DE 15 98 797 A. In this method, impurities are first filtered out of a conveying medium, and the cleaned conveying medium, containing only the smoke particles, is then passed through an ionization chamber.

[0005] DE 36 43 813 A1 discloses a smoke detector for a ventilation duct with a flow-through smoke density measuring device. This device is arranged in a holder with an opening that, when attached to a wall of the ventilation duct, corresponds to a hole in the wall. Air guide elements protruding through the hole into the ventilation duct are arranged in front of the opening.

[0006] Further housings for smoke detectors are known from CN 1 08 765 852 A and CN 1 10 939 921 A.

[0007] The object of the present invention is to propose improvements with regard to a smoke detector with regard to its impairment by dust.

[0008] The object is achieved by a housing according to patent claim 1. Preferred or advantageous embodiments of the invention and other categories of invention emerge from the further claims, the following description and the attached figures.

[0009] The housing is a housing for a smoke detector. In other words, the smoke detector is to be accommodated in the housing as intended. This can be a complete smoke detector with its own housing or a smoke detector module without its own housing. The housing is one that has a proper operating condition. In this condition, it is exposed to a flow of air. The “operating condition” includes both the assembly condition of the housing; i.e. the housing is installed at a specific location; and the actual operating condition, i.e. the housing and thus the smoke detector is actually exposed to an air flow.

[0010] By design, air flows in or along a specific flow direction. Any or all conceivable flow directions can be considered for the housing, as long as they lie in a (common) flow plane. The flow must therefore occur in a specific plane, but can take any direction (360°).

[0011] "Lying in the (common) flow plane" is to be understood broadly here, namely that the flow can be either (exactly) parallel to the plane or inclined to the flow plane within an angular range of up to + / - 25°. In other words, the flow plane merely specifies a central direction / plane for a 50° angular range of possible air flows. For the sake of simplicity, the present discussion will primarily consider a flow in the flow plane (+ / - 0° deviation from the central direction) to explain the invention.

[0012] The term "air" is to be understood in the broadest sense here and can, in principle, also extend to other gases / gas mixtures that are to be monitored by a smoke detector. However, this refers in particular to conventional air, especially air conditioning, i.e., air used and directed as part of the air conditioning of a room. In particular, this refers to air for the air conditioning / ventilation of a vehicle; the housing is installed, in particular, in an air conditioning duct of the vehicle, see below.

[0013] In this case, “intended use” means that the housing is structurally tailored to a specific type of smoke detector / flow / air / installation situation, etc., and is set up for use there; e.g., it is designed for the resulting geometric / material and system requirements, etc. In other words, a particular smoke detector / flow / air / installation situation, etc., is assumed to be known in terms of geometry, size, material properties, ambient conditions, etc. In concrete terms, the properties of the smoke detector / flow / air / installation situation, etc., mentioned here are assumed. This all applies mutatis mutandis to other items / conditions, etc., referred to below as “intended use.”

[0014] The housing has a central axis or one is assigned to the housing. The central axis is aligned perpendicular to the flow plane in relation to or during operation.

[0015] With regard to the central axis, the invention therefore also assumes that the housing is mounted and flowed against as intended. In other words, the invention presupposes the following conditions: The housing has an intended air flow direction in which the air flows against the housing. Various flow directions are possible; the only decisive factor is that the flow occurs in the flow plane (+ / - 25°, see above). In other words, the housing can be mounted in different air flow directions, which all lie “in one flow plane”. In other words, the housing can be mounted rotated as desired around the central axis, as long as the central axis is perpendicular to the flow plane. The flow against the housing is therefore always perpendicular (+ / - 25°) to the central axis. The general rule for defining the flow direction / flow plane is:The basic flow direction of the air is assumed or assumed. In other words, the flow direction refers to the unobstructed flow case, in which the housing is not present. This means that turbulence or the flow around the housing, i.e., the deflection of air, etc., from the "main flow direction," are not taken into account here with regard to the definition of the flow direction.

[0016] The housing has an interior space. The interior space contains a mounting area. The mounting area is an area within the interior where the smoke detector is intended to be placed. Therefore, the smoke detector is intended to be positioned in the mounting area when in operation.

[0017] The housing has an opening. This runs parallel to the flow plane and is penetrated by the central axis. The opening has an opening area that is surrounded or delimited by an edge of the opening. The "run to the flow plane" is to be understood as meaning that both the edge and the opening area run parallel to the flow plane. Thus, during operation, the opening is exposed to the passing air. In other words, the opening is swept by air (again, not including eddies, etc., that arise from the air flowing past the housing / opening).

[0018] The housing is designed to be airtight with respect to the interior, except for the opening. In other words, the opening is the only opening through which air, and thus any smoke / aerosols / dust carried within it, can enter the interior of the housing and thus potentially reach the mounting area and thus the smoke detector.

[0019] A grille structure is arranged in the opening. "In" is also to be understood broadly here. This means that the grille structure can, for example, be flush with the opening, set back from the housing towards the interior, or protrude from the housing towards the interior. "In" here is to be understood in the sense of "at / in the area of ​​the opening / interacting with the air flowing past, etc." The crucial point is that the grille structure has an effect on the air flowing past or into the opening and, in particular, would flow in more or differently without the grille structure.

[0020] The grid structure contains at least two grid components in the form of plates or flat structures or strips, etc. These are therefore flat and extend or run parallel to the central axis with regard to their area. The grid components are arranged in such a way that at least their end faces, in particular the entire grid components, are crossed in the manner of a grid. The end faces are as follows: In relation to a direction parallel to the central axis, which points from the interior through the opening into an exterior space of the housing, the “end faces” in question are those that are oriented, i.e. point, in this direction. In relation to the opening area / opening, the grid components therefore cross each other and therefore do not run parallel to one another. As a result of the crossed orIn a grid arrangement, at least one of the grid components is not aligned parallel to any flow direction, but diagonally or perpendicular to it. The grid components are in particular flat strips or plates. At least two of the grid components run in particular perpendicular to one another, i.e. they form a 90° angle with one another. What is crucial, however, is the subdivision of the (larger) opening into (smaller) partial openings in the form of grid cells by the grid, i.e. the grid structure or the crossed grid components. The geometric shape of the grid cells is less important here. Other grid components can then also be designed parallel to one another, resulting, for example, in a multiple diamond or grid structure. In or through the grid structure, partial openings in the form of grid cells are created that are smaller than the entire opening.

[0021] The opening or its edge (line) is in particular round and in particular circular.

[0022] By arranging the opening parallel to the (intended) airflow plane, the housing is designed to be directionally independent of any flow direction within the airflow plane, simplifying installation of the housing when the airflow plane is known—independent of the flow direction, so to speak. The grille components make it difficult for passing air to penetrate into the interior. Any dust particles enter the interior at a lower speed and are therefore less harmful to the smoke detector.

[0023] In a preferred embodiment, the housing has an end wall, wherein the end wall contains the opening. In other words, the opening is an opening in the end wall. This makes it easy to create the opening in a surrounding end wall.

[0024] In a preferred variant of this design, the end wall is flat. Such stone walls are particularly easy to construct.

[0025] In an alternative variant, the end wall is designed to taper toward the opening relative to the central axis. In particular, the end wall is designed to be rotationally symmetrical about an axis of symmetry that runs parallel to the central axis, in particular conical about the central axis, which then represents the axis of symmetry. In particular, the opening forms the end of the respective cone.

[0026] This allows for particularly good airflow in the area of ​​the opening, particularly with airflow as parallel as possible to the opening surface. This makes it particularly difficult for dust to penetrate through the opening into the interior.

[0027] In a preferred embodiment, the grid structure is recessed from the opening (or relative to the housing / edge of the opening) toward the interior. Alternatively, the grid structure is flush with the opening. In a third alternative, the grid structure is arranged so as to protrude from the interior relative to the opening, protruding from the opening to the outside of the housing. Each of the three variants has corresponding advantages and disadvantages with regard to its flow characteristics and can be selected for specific applications depending on requirements.

[0028] In a preferred embodiment, the opening is surrounded by a collar. The collar is a collar-shaped section / part of the housing that protrudes from the rest of the housing. This also improves the flow of air flowing past the opening. The collar runs parallel to the central axis and is, in particular, a (particularly straight) circular cylinder, especially in combination with a circular opening. The opening is then formed by the free end or front end of the collar.

[0029] In the event that an end wall is present, the collar is part of the end wall and the end wall contains or has the opening on the collar.

[0030] In a preferred embodiment, the housing has a housing section (i.e., a longitudinal section) on at least one longitudinal section of the central axis that is rotationally symmetrical and concentric with the central axis. This embodiment is particularly combined with the conical end wall. In particular, the housing consists exclusively of the end wall and the housing section in question, as well as, if appropriate, a rear wall. In particular, this embodiment is also combined with a collar.

[0031] Alternatively, the housing has the aforementioned housing section on the longitudinal section, which, however, has a polygonal cross-section in a plane transverse to the central axis. In other words, the housing is polygonal in this longitudinal section, in particular rectangular or square in cross-section. This is particularly combined with the flat end wall, resulting in an overall cuboid or cube-shaped housing. In particular, no collar is provided on the end wall. Such housings are particularly easy to implement.

[0032] In a preferred embodiment, the mounting area is arranged in the housing such that it is spaced apart from the opening. In particular, it is located at a location as far away from the opening as possible, for example, on a rear wall of the housing opposite the front wall. This maximizes the path from the opening to the mounting area and thus to the smoke detector, reducing the likelihood of dust particles from the opening reaching the smoke detector.

[0033] In a preferred embodiment, the grid structure contains three, four, or more, in particular eight, grid components. The grid components are arranged such that their end faces (as explained above) form a grid structure. In particular, some, e.g., four, parallel grid components are crossed with the same number of further parallel grid components—in particular at right angles. In other words, a grid-shaped grid structure is provided. The grid components are thus arranged in the manner of a grid, in particular a rectangular, in particular regular grid of planar grid components in the form of strips or plates.

[0034] The object of the invention is also achieved by a smoke detector assembly according to claim 10. The smoke detector assembly contains the housing according to the invention, as explained above, and the smoke detector. The smoke detector is (as intended) arranged in the mounting area in the interior of the housing.

[0035] The smoke detector assembly and at least some of its possible embodiments, as well as the respective advantages, have already been explained in connection with the housing according to the invention. In particular, the preferred embodiments mentioned above in connection with the housing also constitute preferred embodiments of the smoke detector assembly.

[0036] The object of the invention is also achieved by a flow channel according to claim 11. This is a flow channel for the air described above. The flow channel contains the housing according to the invention, as already explained above. In the operating state, the flow channel has the flow plane and, in particular, a specific flow direction for the air at the location of the housing. The housing is arranged in the flow channel such that the central axis is oriented perpendicular to the flow plane / flow direction.

[0037] The flow channel and at least some of its possible embodiments, as well as the respective advantages, have already been explained in connection with the housing according to the invention. In particular, the preferred embodiments mentioned above in connection with the housing also constitute preferred embodiments of the flow channel.

[0038] In a preferred embodiment, the flow duct is an air conditioning duct / pipe. This serves or is designed for the intended conveyance of air in the form of conditioned air. Such air conditioning ducts are particularly susceptible to dust pollution, which is why smoke detectors installed in the air conditioning ducts are particularly effectively protected by the housing.

[0039] In a preferred embodiment, the air conditioning duct is one that is intended to be installed in a vehicle or is installed in it. The vehicle is, in particular, a (large-capacity) vehicle for passenger transport, in particular a train, a bus, or an aircraft. Air conditioning ducts in such vehicles generally have a particularly high air throughput and are heavily exposed to dust, which is why measures to protect smoke detectors from dust are particularly necessary and, according to the invention, particularly effective. A vehicle air conditioning duct provides air conditioning for the vehicle, for example, a passenger cabin of a motor vehicle, train, bus, or aircraft.

[0040] The invention is based on the following findings, observations, and considerations and also includes the following preferred embodiments. These embodiments are sometimes referred to as "the invention" for simplicity. The embodiments may also contain parts or combinations of the above-mentioned embodiments or correspond to them and / or may also include previously unmentioned embodiments.

[0041] According to the invention, a dust protection (housing) for smoke detectors is obtained.

[0042] It creates a protective casing around a smoke detector to prevent dust accumulation over time, which impairs the normal performance of the smoke detector.

[0043] The invention is based on practical observations that, for example, smoke detectors in railway carriages frequently trigger false alarms due to dust or maintenance problems. This is particularly noticeable for smoke detectors installed in HVAC (heating, ventilation, and air conditioning) ducts, whose inlet is located near the platform.

[0044] One possible solution would be to use filters to filter dust, which would lead to blockages and require regular cleaning / replacement of the filters.

[0045] The basic idea of ​​the invention is to mount a smoke detector on a ceiling and also to use a vortex interrupter (grille components, grille) and to protect the smoke detector 360 degrees regardless of the current flow direction (as long as the flow direction is in the flow plane perpendicular to the central axis).

[0046] The basic idea of ​​the invention is also a housing that is defined in such a way that it protects the smoke detector in the direction perpendicular to the air flow. It is intended to protect the smoke detector from the direct flow of dust-laden air into the measuring chamber, thus allowing as little flow as possible at the location of the smoke detector. The grid-like construction (of the grid components in the opening) further slows the speed of the air (in the interior or when entering through the opening into the interior), which leads to a loss of kinetic energy that is insufficient to transport the dust into the measuring chamber (of the smoke detector). Although the dynamic operating point allows only a few dust particles (in the housing), the smoke aerosol diffuses freely (into the housing and thus) into the smoke chamber (of the smoke detector), depending on the smoke concentration within the dust protection, i.e., in the interior of the housing.

[0047] The invention provides the advantage of a maintenance-free dust protection for smoke detectors in HVAC ducts or applications with high flow rates. At the same time, it provides high smoke detection performance for fire aerosols.

[0048] The invention protects the smoke detector from dust accumulation while allowing it to function normally, particularly in heavily dusty airflows and high flow velocities between 2m / s and 10m / s.

[0049] The grille components result in a design that prevents direct airflow into the interior and thus the smoke detector. The grid-like construction of the grille structure reduces turbulence in the interior, thereby depriving dust particles of sufficient energy to shoot into the interior of the housing.

[0050] This results in low air flow velocities inside the housing.

[0051] Further features, effects, and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. Each of these figures shows a schematic diagram: Fig. 1 a flow channel with smoke detector in a housing in a partially transparent perspective view obliquely from above, Fig. 2 an alternative housing in a perspective view from below, Fig. 3 the detail III from Fig. 2 housings in a partially transparent view, Fig. 4 the housing Fig. 2 when air flows in a cross-section in side view, Fig. 5 an alternative fully rotationally symmetrical housing in a perspective view obliquely from above, Fig. 6 an alternative housing in a perspective view obliquely from below, Fig. 7 an alternative cuboid-shaped housing in a perspective view obliquely from below.

[0052] Fig. 1 shows a flow channel 2, symbolically indicated here only by dashed lines. In its illustrated operating state B, air 4 flows through it. The flow channel 2 is an air conditioning duct 6 in a vehicle 8 (not shown in detail), in this case a train for passenger transport. The conveyed air 4 is air conditioning air 10 for air conditioning a passenger cabin of the vehicle 8 (not shown in detail). In the flow channel 2, a fixed flow direction 14 of the air 4 is provided in the operating state B.

[0053] The flow channel 2 contains a smoke detector assembly 20. This comprises a smoke detector 22 and a housing 30. The smoke detector 22 and the housing 30 are also in operating state B. The smoke detector 22 monitors the air 4 for smoke gases in a manner not explained in detail and triggers an alarm signal upon detection. The housing 30 protects the smoke detector from exposure to / contamination by dust transported with the air 4.

[0054] The housing 30 has a central axis 32. A flow plane 12 is assigned to the central axis 32, which runs perpendicular to the central axis 32. The housing 30 is installed as intended in the air conditioning duct 6: This requires that air 4 flows against it in a flow direction 14 that lies in the flow plane 12. The housing 30 is therefore arranged in the air conditioning duct such that the flow plane 12 is positioned so that the flow direction 14 lies in it. The central axis 32 is thus aligned perpendicular to the flow direction 14 as intended. The rotational position of the housing 30 about the central axis 32 is arbitrary; this does not need to be taken into account when installing the housing 30 in the air conditioning duct 6.

[0055] The housing 30 has an interior space 34 enclosed by the housing 30. The interior space 34 has a mounting area 36. In operating state B, the smoke detector 22 is to be arranged in this mounting area 36 and is actually arranged there.

[0056] The housing 30 is therefore a housing 30 for the smoke detector 22, which in the operating state B is intended to be exposed to the flow of the air 4 in the flow direction 14, wherein the flow direction 14 lies in the flow plane 12.

[0057] The housing has an opening 38. This is penetrated by the central axis 32 and runs parallel to the flow plane 12. The opening 38 has an edge 42 that defines or surrounds an opening surface 40 of the opening 38. The opening surface 40 or the opening 38 is in Fig. 1 is shown hatched. The edge 42 is a circular ring, the opening area 40 a circular area. The fact that the "opening 38 runs or lies parallel to the flow plane 12" means that the opening area 40 and the edge 42 lie or run parallel to the flow plane 12. In operating state B, the opening 38 is therefore exposed to the air 4 flowing past it in parallel, i.e., it is swept over by the air 4, which in Fig. 1 is strongly symbolized by an arrow 44.

[0058] A grid structure 46 is arranged in the opening 38. The grid structure 46 contains a total of eight grid components 48. Each of the grid components 48 is a flat strip or band extending parallel to the central axis 32. Four of the grid components 48 are arranged parallel to one another, with the two groups of four grid components 48 intersecting at right angles to one another. In other words, the grid components 48 are arranged within the grid structure 46 in the manner of a grid 50 and therefore intersect at right angles.

[0059] If one defines a direction along the central axis 32, which points from the interior space 34 through the opening 38 into an exterior space surrounding the housing 30, end faces 52, which are straight lines in this case, result on the grid components 48. These end faces 52 form a rectangular and regular grid with square grid cells.

[0060] The housing 30 has an end wall 60 containing the opening 38. The end wall 60 is designed to taper conically toward the opening 38 relative to the central axis 32. Here, the central axis 32 forms an axis of symmetry for the end wall 60, which thus extends rotationally symmetrically around the axis of symmetry or central axis 32.

[0061] In Fig. 1, the grid structure 46 or the grid components 48 are arranged to protrude from the opening 38 and away from the interior space 34. In other words, a portion of the grid structure 46 and each of the grid components 48 protrudes from the rest of the housing 30 or its opening 38 or the end wall 60.

[0062] On a longitudinal section 68 of the central axis 32, a housing section 72 is designed to be rotationally symmetrical and concentric with the central axis. The housing section 72 is a circular cylindrical shell. In the present case, the housing 30 consists exclusively of a circular disk-shaped rear wall 70, the housing section 72, the end wall 60, and the grid structure 46.

[0063] The mounting area 36 is arranged in the housing 30 at a distance from the opening 38. Here, a location maximally removed from the opening 38 is selected, namely on the rear wall 70, which is opposite the end wall 60 and thus opposite the opening 38.

[0064] Fig. 2 shows an alternative embodiment of a housing 30, which basically corresponds to the embodiment of Fig. 1 corresponds with the following differences: In contrast to Fig. 1, the housing 30 additionally contains a collar 62, which continues the end wall 60 at its conically tapered end and surrounds the opening 38 and protrudes from the rest of the housing 30 in the direction of the central axis 32. The collar 62 is thus a further part of the housing 30. In the present case, the collar is designed in the manner of a circular cylinder shell and concentrically continues the conically extending end wall 60. The opening 38 is delimited here by a front end or free end of the collar, which forms the edge 42. Due to the protruding collar 62, the lattice structure 46 is now set back with respect to the opening 38 toward the interior space 34.

[0065] In operating state B, however, it is ensured that the housing 30 and especially its interior 34, except for the opening 38, are designed to be sealed against the incoming air 4.

[0066] Fig. 3 shows in a partially transparent representation the detail III from Fig. 2. Here, the two crossed sets of four parallel grid components 48 of the grid structure 46 can be seen again. It also illustrates how the grid components 48 and grid structure 46 are recessed from the opening 38 to the interior space 34 in the collar 62 and the housing 30, respectively. It can also be seen how the grid components 48 extend along the central axis 32 beyond the collar 62, expanding conically for a short distance along the end wall 60 into the interior space 34.

[0067] Fig. 4 shows a cross section through the flow channel 2 according to Fig. 1 and the housing 30 mounted therein according to the Fig. 2 and Fig. 3 in operating state B. The housing 30 is thus or is being flowed against by the air 4 in the direction of flow 14. The air 4 or its flow is represented here by flow vector arrows. Here, it can be seen that the air 4 flows past the opening 38 practically parallel. Due to the grid structure 46, the air 4 is almost completely slowed down upon entry into the opening 38 or the interior space 34, so that there is practically no flow of air 4 in the interior space 34. Any dust particles (not shown) that are carried along by the air 4 therefore do not reach the interior space 34 at all, or if they do, then only at a virtually negligible speed. Based on gravity (in Fig. 4 directed downwards), these remain in the lower area of ​​the interior 34 and in any case do not reach the smoke detector 22, which is therefore not contaminated by dust. Smoke aerosols, on the other hand, can pass unhindered through the opening 38 and the interior 34 to the smoke detector 22 and trigger it.

[0068] Fig. 5 shows an alternative housing 30. This corresponds to the one in the Fig. 2 and Fig. 3 with the following differences: The case has a diameter D of 182 mm and is overall less high (in the direction of the central axis 32). The case 30 is completely smooth and regular.

[0069] Fig. 6 shows a further embodiment of a housing 30, which essentially corresponds to that of Fig. 2 and Fig. 3 corresponds.

[0070] Fig. 7 shows another alternative housing 30. This corresponds to Fig. 1, that no collar is provided here either. However, here the lower end wall 60 is flat and parallel to the flow plane 12. The grid structure 46 protrudes according to Fig. 1 protrudes from the end wall 60 or the opening 38. The housing section 72 has a polygonal (here square) cross-section in a transverse plane to the central axis 32 and thus parallel to the flow plane 12. The side length L of the housing section 72 is 182 mm. In other words, the housing 30 is designed like a cuboid with a square base. List of reference symbols 2 flow channel 4 Air 6 air conditioning duct 8 vehicles 10 Climate air 12 Flow level 14 Flow direction 20 smoke detector arrangement 22 smoke detectors 30 housings 32 Central axis 34 Interior 36 Assembly area 38 Opening 40 opening area 42 Rand 44 Arrow 46 lattice structure 48 Grid component 50 grids 52 end faces 60 front wall 62 collars 68 Longitudinal section 70 rear wall 72 Housing section B Operating state D Diameter L side length

Claims

[1] Housing (30) for a smoke detector (22) which, in an operating state (B), is intended to be exposed to a flow of air (4) in a flow direction (14) lying in a flow plane (12), - with a central axis (32) aligned perpendicular to the flow plane (12), - with an interior space (34) containing a mounting area (36) in which the smoke detector (22) is to be arranged as intended in the operating state (B), - with an opening (38) running parallel to the flow plane (12) and penetrated by the central axis (32), which opening is exposed to the passing air (4) in the operating state (B), - wherein the housing (30) is designed to be sealed against the flow of air (4) with respect to the interior space (34) except for the opening (40), - with a grid structure (46) arranged in the opening (38), - wherein the lattice structure (46) contains at least two lattice components (48), each extending flatly parallel to the central axis (32), which are arranged such that at least their end faces (52) - oriented in a direction of the central axis (32) from the interior (34) to the opening (38) - are crossed. [2] Housing (30) according to claim 1, characterized by that the housing (30) has an end wall (60) containing the opening (38). [3] Housing (30) according to claim 2, characterized by that the end wall (60) is flat. [4] Housing (30) according to claim 2, characterized by that the end wall (60) is designed to taper conically towards the opening (38) with respect to the central axis (32). [5] Housing (30) according to one of the preceding claims, characterized by that the grid structure (46) is set back from the opening (38) towards the interior space (34) or is arranged flush with it or projecting away from the interior space (34). [6] Housing (30) according to one of the preceding claims, characterized by that the opening is surrounded by a collar (62) which is part of the housing (30) and protrudes from the rest of the housing (30) [7] Housing (30) according to one of the preceding claims, characterized by that the housing (30) has a housing section (72) at least on a longitudinal section (68) of the central axis (32), - which is rotationally symmetrical and concentric to the central axis (32) or - which has a polygonal cross-section in a transverse plane to the central axis (32). [8] Housing (30) according to one of the preceding claims, characterized by that the mounting area (36) is arranged in the housing (30) at a distance from the opening (38). [9] Housing (30) according to one of the preceding claims, characterized by that the lattice structure (46) contains three or more lattice components (48). [10] Smoke detector arrangement (20), -with a housing (30) according to one of the preceding claims, and - with the smoke detector (22) which is arranged in the mounting area (36) in the interior (34). [11] Flow channel (2) for air (4), - with a housing (30) according to one of claims 1 to 9, - wherein the flow channel (2) in the operating state (B) has the flow plane (12) for the air (4) at the location of the housing (30), wherein the housing (30) is arranged in the flow channel (2) such that the central axis (32) is aligned perpendicular to the flow plane (12). [12] Flow channel (2) according to claim 11, characterized by that the flow channel (2) is an air conditioning channel (6) for guiding air conditioning air (10) as air (4). [13] Flow channel (2) according to claim 12, characterized by that the air conditioning duct (6) is one that is intended to be installed in a vehicle (8).

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