WO2020078859A1

WO2020078859A1 - Smoke detector for detecting smoke in sections, and vehicle having a smoke detector

Info

Publication number: WO2020078859A1
Application number: PCT/EP2019/077645
Authority: WO
Inventors: Andreas Brunnflicker; Helmut Adamek
Original assignee: Bombardier Transportation Gmbh
Priority date: 2018-10-15
Filing date: 2019-10-11
Publication date: 2020-04-23
Also published as: CN113168752A; CN113168752B; EP3867888A1; DE102018125494A1

Abstract

The invention relates to a smoke detector (100) having an elongate first chamber (110) and an elongate second chamber (120), the first chamber (110) and the second chamber (120) extending in a common longitudinal direction. A first wall (111) has one or more first openings (152), the first wall (111) at least partially delimiting the first chamber (110) so that smoke can pass into the first chamber (110) of the smoke detector at different positions in the longitudinal direction of the smoke detector.A second wall (121) which separates the first chamber (110) from the second chamber (120) has one or more second openings (151), the first chamber (110) being connected to the second chamber (120) via the one or more second openings (151) so that gas can be exchanged between the first chamber (110) and the second chamber (120) and through the first chamber (110) and the second chamber (120). A transmitter (130) is situated in one of the two chambers (110, 120), and a receiver (140) is situated in the other of the two chambers (110, 120).

Description

description

RAU CH M ELD ER TO M STRETCHES WHEN S E EKTKTI ERE N VO N RAU CH, SOWI E

VEHICLES ONLY WITHIN A SMOKE

Technical field

The present invention relates to a smoke detector for the partial detection of

Smoke, in particular for height-independent detection of smoke in sections, for example in vehicles and in buildings.

Prior art

Electronic smoke detectors usually have a transmitter and a receiver, the triggering of the signal of the smoke detector depends on the presence of smoke.

Photo-optical smoke detectors are used particularly frequently, in which the transmitter can comprise a special light-emitting diode and the receiver can comprise a light-sensitive resistor. For example, such a smoke detector can be set up such that a light beam emitted by the transmitter only hits the receiver when smoke particles scatter or deflect it.

The US Pat. No. 6,831,289 discloses a detection device for scattered light, as part of a hazard detector, such as a fire detection system.

Disadvantages of the prior art

Such smoke detectors, however, deliver when the smoke is not immediately on or in

Smoke detector is not a satisfactory result since this smoke detector

only allow selective smoke detection. An alarm can therefore only be triggered if the smoke has already spread to the smoke detector, i.e. has usually reached the ceiling area. Furthermore, due to the local limitation of the smoke detection with an increased financial outlay

Equipping large rooms with the goal of comprehensive surveillance. This is all the more the case since such smoke detectors are complicated components for which special injection molded parts have to be manufactured in large series. Problem

The object of the present invention is therefore to provide a smoke detector,

which enables smoke to be detected over larger areas in order to be able to detect smoke not only locally at one point, but continuously over the length of a room.

Solution according to the invention

The above object is according to an embodiment by a smoke detector

Claim 1 solved. Further advantageous embodiments are specified in the subclaims.

According to one embodiment, the smoke detector comprises a first and a second

Room. These spaces can be elongated, for example, to enable smoke to be detected not only at certain points. For this purpose, the first and the second room of the smoke detector according to the invention can extend along a common longitudinal direction.

In contrast to the embodiments described here, conventional ones include

Smoke detector a cavity that is only a few millimeters high. A labyrinth with narrow gaps surrounds such a cavity so that no light can penetrate from outside. If smoke gets into the cavity through the labyrinth, a light beam emitted by a transmitter, for example, is scattered and so on

possibly routed to a receiver, which triggers an alarm. Such a conventional smoke detector is limited to the detection of smoke in a narrow area around the installation location of the smoke detector. If the smoke is not directly on or in the smoke detector, no alarm is triggered.

In contrast, smoke detectors according to the embodiments described here can detect smoke along the entire length of the smoke detector, for example during installation, for example along cables or various electrical components. The smoke detector can, for example, extend over an entire length of a room to be monitored, for example along cable ducts or along the ceiling of installation rooms, and thus monitor the entire room. [0011] Furthermore, for example, a vertical or inclined mounting of the

Smoke detector according to the invention that a e.g. Smoldering fire creeping on the floor can be detected just as quickly as "hot" smoke collecting on the ceiling. If the air movement is constant or not predictable, such as "stagnant" air, smoke will flow along the elongated air according to the invention

Smoke detector thus recognized earlier than with a conventional smoke detector that can only detect a small spatial area.

[0012] Furthermore, the smoke detector has a first wall with at least one, two, three or more first openings. The first wall at least partially delimits the first room. In this sense, the expression “at least partially” is to be understood in such a way that the entire circumference of the first room is not necessarily described by the first wall. For example, the first wall can only cover an area corresponding to 50%, 60%, 70%, 80% or 90% of the total size of the first room

For example, a cylindrical first space is delimited as such a first wall only over the surface whose points have the same radius from its axis. Furthermore, e.g. a cuboid first room can only be delimited by two, three or four of its side faces by the first wall.

The one, two, three or more first openings within the first wall

enable smoke at the positions of the first openings and thus at one, two, three or more different positions along the longitudinal direction of the smoke detector to get into the first room of the smoke detector.

Furthermore, the smoke detector has a second wall separating the first room from a second room, which in turn comprises at least one, two, three or more second openings. The first room is connected to the second room via the one, two, three or more second openings. For example, such a second wall can run within the first room and thus span a second room within the first room. Likewise, the second wall can extend between a first room and a second room running parallel thereto and thus separate the first room from the second room.

A gas exchange between the first space and the second space is made possible by the at least one, two, three or more second openings of the second wall. Consequently For example, smoke can move from the outside through the first or the first openings, through the first space, through the second or the second openings, until the second space.

In addition, the smoke detector has a transmitter and a receiver, whereby under

Normal conditions, d. H. without the presence of smoke, a signal emitted by the transmitter cannot easily hit the receiver and therefore no alarm is triggered under normal conditions. The second wall separates the transmitter from the receiver. For example, the smoke detector can have a transmitter in one of the two rooms and a receiver in the other of the two rooms. Here, e.g. the transmitter in the first room and the receiver in the second room. When selecting the position of the receiver within the smoke detector, the design-related exposure of the receiver to undesired external interference signals is advantageously taken into account. A receiver is preferably outside the possible angle of incidence of external radiation, that is to say external radiation

Interference signals that are not emitted by the transmitter are arranged. For example, the receiver can be arranged in an inner second room while the transmitter is in an outer first room. The transmitter and receiver are preferably an optical transmitter and an optical receiver.

A transmitter can be provided, for example, by a special light-emitting or laser diode, the signal of the transmitter being based on optical radiation. A receiver can be provided, for example, by means of a light-sensitive resistor that can detect such optical radiation. As described above, when designing the smoke detector, it should be noted that the optical radiation emitted by the transmitter cannot hit the receiver directly. In contrast, it causes

The presence of smoke, which can move through the at least one first opening, through the first space, through the at least one second opening and through the second space, such that the optical radiation emitted by the transmitter is deflected by smoke particles in its beam path can. Depending on the position (s) of the first or second opening (s) and the type and amount of

Smoke particles can thus at least partially deflect optical radiation from the transmitter in the direction of the receiver and can thus be detected by the latter. In this case, the smoke detector triggers the alarm to display the smoke development. Such a triggering of the Alarm can depend on the exceeding of a predetermined threshold value of the signal intensity detected by the receiver.

According to one embodiment of the smoke detector according to the invention, the second room is arranged within the first room of the smoke detector. The first room can at least partially surround the second room. A partial, i.e. not complete

The surroundings of the second room through the first room can result, for example, from different lengths of the first and second rooms. Likewise, the first room can also substantially completely surround the second room, with end faces of the second room not necessarily having to be surrounded by the first room.

According to a further embodiment of the smoke detector according to the invention, the lengths of the first and the second room each correspond to at least twice the common width of the first and second room. The length of the first or second space preferably corresponds to at least three times, particularly preferably at least four times, five times or ten times the common width of the first and second spaces. The smoke detector therefore preferably has an elongated shape, for example a tubular shape, and can therefore be provided in any lengths. It is therefore possible to adapt the length of the smoke detector to the length of the room to be monitored. This allows larger areas to be used, unlike previous ones

Smoke detectors are monitored. The smoke detector can, for example, have a length of at least 50 cm, typically at least 1 m.

According to a preferred embodiment, the first and the second room of the smoke detector according to the invention are approximately the same length. The person skilled in the art understands approximately the same length that the length deviations are in one

move the design-related tolerance range.

According to a further embodiment, the smoke detector according to the invention extends from a first in the longitudinal direction to a second end in the longitudinal direction. The transmitter and the receiver can, for example, at the opposite end of the

Smoke detector can be arranged. Alternatively, the transmitter and the receiver can be arranged at the same end of the smoke detector. Such a structure enables e.g. a

Equipping the smoke detector with electrical connections at only one of its two ends. Furthermore, a smoke detector according to the invention can have a first and a second room, each with two opposite end openings. The

Opposing end openings are located, for example, within the outer sectional planes delimiting the first space or second space with the longitudinal axis of the first or second space. These end openings can also be closed by one or more closure elements. A closure element thus at least partially closes such an opening. This prevents, for example, the penetration of undesired external interference signals through the end openings at the ends of the smoke detector.

Preferably, the transmitter and the receiver of the smoke detector are each in a closure element. Alternatively, the transmitter and the receiver can also be arranged within only one closure element.

[0024] As described above, according to one embodiment, the first room of the

Smoke detector to the outside of the first wall and to the inside of the second wall. Such a structure is made possible, for example, by the second space extending within the first space. A parallel arrangement of the first and the second space next to one another is also possible. In both embodiments, however, the at least one or more second openings of the second wall are preferably arranged offset to the at least one or more first openings of the first wall. Such an offset of the first and second opening (s) is preferably set up in such a way that incidence of external scattered light on the receiver of the smoke detector is prevented. It is thus possible to prevent the receiver from being influenced by undesired external interference signals and thus to trigger a false alarm. Such an arrangement of the openings is particularly advantageous if the transmitter and the receiver are arranged on different sides of the smoke detector.

Such an arrangement can be achieved, for example, by arranging the second openings of the second wall and the first openings of the first wall at different positions along the longitudinal axis of the smoke detector. Depending on the particular embodiment of the smoke detector, an arrangement in which the second openings point in a different direction than the first openings is also advantageous. The direction of a first or second opening is determined, for example, by the angle between the

Normal vector of the respective opening area and the longitudinal median plane of the smoke detector Are defined. For example, the first or second openings can be arranged on different sides along the longitudinal direction of the smoke detector. If the first or second openings lie on exactly opposite sides along the longitudinal direction of the smoke detector, the difference between their directional angles as defined above is 180 degrees. The directions of one, two, or more first or second

Openings be the same or different.

[0026] Furthermore, according to a further embodiment, some or all of the first

Openings of the first wall can be provided with a filter. Such a filter is permeable to smoke, but prevents small animals and insects such as e.g.

Spiders, mites or wasps nest in the smoke detector and thus lead to a disturbance in smoke detection.

According to a preferred embodiment, the second wall is formed by an inner tube and the first wall by an outer tube surrounding the inner tube. As a result, the second space is delimited by the inner tube and the first space is provided by the space located between the inner tube and the outer tube. The outer tube and the inner tube are preferably delimited at their respective ends by closure elements. For example, one of the closure elements can contain the transmitter and the opposite closure element the receiver. A construction is particularly preferred in which the inner tube is held by the closure elements within the outer tube.

In addition, in this preferred embodiment, the inner tube can be a variety of

Have openings that form the plurality of second openings of the second wall. At the same time, the outer tube can have a multiplicity of openings which form the plurality of first openings of the first wall. Preferably, the

Openings of the outer tube with respect to the longitudinal axis of the outer tube in a first radial angular range and the openings of the inner tube with respect to the longitudinal axis of the outer tube in a second radial angular range, which does not overlap with the first radial angular range. The two radial angular ranges therefore point in different radial directions with respect to the longitudinal axis. Such a structure ensures that external stray light is not directly in the smoke detector and on the Surface of the receiver can hit, which negatively affects the

Smoke detection and possibly triggering a false alarm.

The above-described embodiments can be combined with one another as desired.

Brief description of the figures

[0030] The accompanying drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention. The elements of the drawings are relative to one another and are not necessarily to scale.

The same reference numerals designate the same or correspondingly similar parts.

FIG. 1 shows a schematic view of a smoke detector in longitudinal section.

Figures 2 and 3 show a spatial, schematic view of a closure element with a transmitter or a receiver according to one embodiment.

Figures 4A to 4C and 5A and 5B show, according to one embodiment, a spatial, schematic view of a tubular smoke detector (Figure 4A) with an outer tube (Figure 4B), an inner tube (Figure 4C), a first closure element (Figure 5A) and a second closure element (FIG. 5B).

6 shows a spatial, schematic view of an embodiment of the

Smoke detector in an open state.

Figure 7 shows a schematic view of a smoke detector according to another

Longitudinal section embodiment.

Figure 8 shows a spatial, schematic view of a closure element with a

Transmitter and a receiver according to a further embodiment.

FIG. 9 shows a spatial, schematic view of a smoke detector according to a further embodiment. Embodiments

To clarify the overall understanding is based on a schematic view in

Figure 1 shows a smoke detector 100 according to the invention in cross section. This comprises an elongated first space 110 and an elongated second space 120.

Figure 1 illustrates an embodiment of the invention in which the second

Space 120 extends tubularly within the first tubular space 110 along a common longitudinal direction and a common longitudinal axis. The second room 120 is bounded or defined by a second wall 121 and the first

Room 110 bounded by a first wall 111 and by the second wall 121 or

Are defined. Furthermore, in the embodiment shown in FIG. 1, both the first and the second wall each have a plurality of openings 151, 152, which can be arranged, for example, evenly distributed along the entire extent of the respective first and second spaces 110, 120. The number of openings 152 between the first and second spaces 110, 120 and the number of openings 151 between first space 110 and the outside environment may be the same, but may also be different. It is also possible that the opening cross section of the openings 151, 152

can be different. However, it can also be the same for all openings 151, 152.

The cover with filters 190 is shown as an example for some of the first openings 151 in the first wall 111. At the left first end 160 of the smoke detector 100 constructed in this way, as shown in FIG. 1, there is a first end opening 112 within the first room 110 with a transmitter 130 arranged therein

Radiation, for example in the visible or near infrared range, only in the first room 110 parallel to the longitudinal axis, but not directly in the second room 120. At the right second end 170 of the smoke detector 100 constructed in this way is located within the second room 120 has a second end opening 122 with a receiver 140 arranged therein. FIG. 1 further shows that the smoke detector in the embodiment shown has a length I which is a multiple of its radius r, in the case of a circular cross section, or its maximum width, in the case of any other cross section , corresponds.

Figures 2 and 3 illustrate two schematic views

Closure elements 180a, 180b, the one with the embodiment shown in Figure 1 Smoke detector 100 according to the invention can be combined. The closure element 180a shown in FIG. 2 thus comprises a ring-shaped transmitter 130, or a transmitter 130 which is only arranged in the ring area around the second space 120. It is also possible for a plurality of transmitters 130 to be arranged in a ring. The

Closure element 180a with the transmitter 130 is adapted to close the first space 110 of the smoke detector 100 from FIG. 1 at one of its end openings 112. In contrast, the closure element 180b shown in FIG. 3 has a receiver 140 within the second space 120, or at one of its ends, and because of its cylindrical structure, it is suitable for the second space 120 of the smoke detector 100 from FIG. 1 at one of its end openings 122 to close.

FIG. 4A shows a three-dimensional representation of an elongated tubular smoke detector which has an outer tube 101 and an inner tube 102, for example coaxial with the outer tube 101. The outer tube 101 is shown in Figure 4B and the inner tube 102 is shown in Figure 4C. The jacket wall 111 of the outer tube 101 forms a first wall, while the jacket wall 121 of the inner tube 102 forms a second wall. The second space 120 is delimited by the inner region of the inner tube 102, while the first

Space 110 is delimited by the outer wall 111 of the outer tube 101 and the outer wall 121 of the inner tube 102. The first room 110 therefore surrounds the second room 120.

Both the inner tube 102 and the outer tube 101 each have a plurality of

Openings 151, 152. The openings 151 (first openings) of the outer tube 101 point upward in FIG. 4B, the openings 152 (second openings) of the inner tube 102 point towards the viewer, that is to say they are rotated about the longitudinal axis in relation to the openings 151 of the

Outer tube 101 arranged. As a result, light cannot pass directly through the openings 151, 152 into the interior of the inner tube 102, i.e. get into the second room 120.

[0044] In addition to the plurality of first openings 151, the outer tube 101 has two

opposite end openings 112. In addition to the second openings 151, the inner tube 102 also has two opposite end openings 122.

The inner tube 102 is through a first closure element 181 and a wide

Closure member 182, shown in Figures 5A and 5B, within the

Outer tube 101 held. The closure elements 181, 182 additionally close the respective end openings 112, 122. For example, the second closure element 182 have a shoulder 183 on its outside, on which the outer tube 101 is pushed, for example in a form-fitting manner. At the front 184 of the second

Closure element 182 can be arranged one or more transmitters which radiate in the axial direction, i.e. inside and along the outer tube 101. Specifically, the transmitter or the transmitters radiate into the first space 110, which is annular in cross section and extends between the inner tube 102 and the outer tube 101.

The inner tube 102 is then inserted into the inner opening 185 of the second closure element 182 and held, for example, in a form-fitting manner by the inner opening 185. As a result, the inner tube 102 is held at a distance from the outer tube 101. The transmitters radiate into the space between the inner tube 102 and the outer tube 101, i.e. in the first room 110.

The first closure element 181 also has an inner opening 185 into which the

Inner tube 102 is inserted positively. A receiver is located within the inner opening 185 of the first closure element 181. Radiation emitted by the transmitter or transmitters of the second closure element 182 does not reach the receiver directly, since the direct path through the inner tube 101 is blocked. However, if smoke, or an aerosol, penetrates through the first openings 151 of the outer tube 101 into the space between the outer tube 101 and the inner tube 102 and, if necessary, further through the second openings 152 of the inner tube 102 into the interior of the inner tube 102, the Radiation emitted by the transmitter to the smoke or aerosol parti is not scattered and thereby also reaches the interior of the inner tube 102 and finally the transmitter in the first closure part 181. The scattered light is registered by the receiver, evaluated by suitable electronics and emitted as a warning signal will.

The first closure element 181 can for example be inserted in a form-fitting manner in the outer tube 101. However, it can also have a step like the second closure element 182, onto which the outer tube 101 can be pushed.

Figure 6 illustrates how the embodiment shown in Figure 1 by inserting the in

5 shows the second wall 121 shown in the first wall 111 shown in FIG. 4

can be assembled. Furthermore, FIG. 6 schematically shows electronics for controlling the transmitter and the receiver. Figure 7 shows an alternative embodiment to that shown in Figure 1

Embodiment of the present invention. As shown in FIG. 1, the transmitter 130 is also located in a first room 110 of the smoke detector 100 and the receiver 140 in a second room 120 of the smoke detector 100

However, the alternative embodiment shown differs from the structure shown in FIG. 1 in that both the transmitter 130 and the receiver 140 are arranged in the respective end openings 112, 122 at the same end of the smoke detector 100 shown.

The alternative embodiment shown in FIG. 7 can be used with a device as in FIG. 8

closure element 180 shown can be combined. In contrast to the closure elements 180a, 180b shown in FIGS. 2 and 3, the schematic view shown in FIG. 8 illustrates a closure element 180, which is located both via a transmitter 130 in an outer annular region and via a receiver 140 in an inner cylindrical region Area of the closure element 180.

Figure 9 shows a further alternative embodiment to that shown in Figure 1

Embodiment of the present invention. As shown in FIG. 1, the transmitter 230 is also located at an end opening of a first room 210 of the latter

Smoke detector 200 and the receiver 240 on an opposite one

End opening 222 of a second room 220 of the smoke detector 200. The first room 210 stands over a plurality of first openings 251 in one of its walls 211 (first wall) with the

Environment in connection. The first room 210 and the second room 220 are separated from one another by a second wall 221. The second wall 221 has a plurality of second openings 252, which are arranged offset to the first openings 251 in the first wall 211, so that no direct light can enter the second space 220 from the outside.

However, the alternative embodiment shown in FIG. 9 differs from that in FIG

FIG. 1 and FIG. 7 construction insofar as the second space 220 runs next to and to the first space 210 parallel and not within the first space 210. In addition to the arrangement of transmitter 230 and receiver 240 shown in FIG

opposite ends 212, 222 of the smoke detector 200 is also a construction

corresponding to the alternative embodiment shown in FIG. 7, ie one Arrangement of the transmitter 230 and the receiver 240 at the ends of the first room 210 and the second room 220, which are located at the same end of the smoke detector 200. Optionally, some or all of the first openings 251 can be closed with a filter 290.

[0054] Further exemplary embodiments of the present invention include installation spaces in

Passenger compartments of rail vehicles, ships, aircraft or buses which are equipped with the embodiments of the smoke detector 100, 200 shown in the figures. A smoke detector 100, 200 is preferably arranged along cable harnesses or cable areas within the passenger compartments.

Furthermore, kitchens, industrial halls, warehouses or archives that are associated with the

smoke detectors 100, 200 according to the invention are further exemplary embodiments of the present invention.

While specific embodiments have been shown and described herein, it is within the scope of the present invention to appropriately modify the shown embodiments without departing from the scope of the present invention. The following claims represent a first, non-binding attempt to define the invention in general.

Reference list

100, 200 smoke detectors

101 outer tube

102 inner tube

110, 210 first room

111, 211 first wall

112, 212 end opening

120, 220 second room

121, 221 second wall

122, 222 end opening

130, 230 transmitters

140, 240 receivers

151 first opening

152 second opening

160 first end

170 second end

180, 180a, 180b closure element

181, 182 closure element

183 shoulder

184 end face

185 inside opening

190, 290 filters

195 electronics

I length of the smoke detector

Radius of the smoke detector

Claims

1. smoke detector, having

an elongated first room (110, 210) and one

elongated second space (120, 220), the first space (110, 210) and the second space (120, 220) extending along a common longitudinal direction;

a first wall (111, 211) having at least one, preferably a plurality of first openings (151, 251), the first wall (111, 211) at least partially delimiting the first space (110, 210), so that smoke travels along different positions the longitudinal direction of the smoke detector (100, 200) can get into the first space (110, 210) of the smoke detector (100, 200);

a second wall (121, 221) separating the first space (110, 210) from the second space (120, 220) and having at least one, preferably a plurality of second openings (152, 152), the first space (110, 210) with the second room (120, 220) via the one or more second

Openings (152, 252) are connected to one another so that a gas exchange can take place between the first space (110, 210) and the second space (120, 220) and between the first space (110, 220) and the surroundings;

a transmitter (130, 230) in one of the two rooms

(110, 120, 210, 220) for emitting optical radiation; and

an optical receiver (140, 240) in the other of the two rooms (110, 120, 210, 220) for receiving optical radiation.

2. Smoke detector according to claim 1, wherein

the second space (120) is arranged within the first space (110), and the first space (110) at least partially surrounds the second space (120).

3. Smoke detector according to one of the preceding claims, wherein

the length (I) of the first and second space (110, 120, 210, 220) at least their common double width, in particular at least their common triple width, and in particular at least theirs

common fourfold width.

4. Smoke detector according to one of the preceding claims, wherein

the smoke detector extends from a longitudinally first (160) to a longitudinally second end (170), the transmitter (130) and the receiver (140) at the same end (160, 170) of the smoke detector or at opposite ends (160 , 170) of the smoke detector are arranged.

5. Smoke detector according to one of the preceding claims, wherein

the first space (110, 210) and the second space (120, 220) each have two opposite end openings (112, 122, 212, 222), each of which is closed with a closure element (180, 180a, 180b, 181, 182) , wherein the transmitter (130, 230) and receiver (140, 240) in one of the two closure elements (180) or separately in one of the two

Closure elements (180a, 180b, 181, 182) are arranged.

6. Smoke detector according to one of the preceding claims, wherein

the first space (110) is bounded on the outside by the first wall (111) and on the inside by the second wall (121).

7. Smoke detector according to one of the preceding claims, wherein

the at least one or more second

Openings (152, 252) of the second wall (121, 221) to which at least one or more first openings (151) of the first wall (111, 211) are arranged offset, in particular pointing in different directions, so that the receiver ( 140, 240) is prevented by external scattered light, preferably the at least one or more second openings (152, 252) of the second wall (121, 221) and the at least one or more first openings (151, 251) of the first wall (111, 211) are arranged on different sides along the longitudinal direction.

8. Smoke detector according to one of the preceding claims, wherein

the at least one or more second openings (152, 252) of the second wall (121, 221) and the at least one or more first openings (151, 251) of the first wall (111, 211) are arranged offset such that a direct incidence of optical radiation from the transmitter (130, 230) to the receiver (140, 240) is prevented.

9. Smoke detector according to one of the preceding claims, wherein

the at least one or more first openings (151, 251) of the first wall (111, 211) are provided with a filter (190, 290).

10. Smoke detector according to one of the preceding claims, wherein

the second wall (121) is formed by an inner tube (102) and the first wall (111) by a tube surrounding the inner tube (102)

Outer tube (101) is formed, the second space (120) from

Inner tube (102) is limited and the first space (110) is the space located between the inner tube (102) and the outer tube (101).

11. Smoke detector according to claim 10, wherein

the outer tube (101) and the inner tube (102) are delimited at their respective ends by closure elements (180a, 180b, 181, 182), one of the closure elements (180a, 180b, 181, 182) being the transmitter (130) and the other the closure elements (180a, 180b, 181, 182) has the receiver (140).

12. Smoke detector according to claim 11, wherein

the inner tube (102) from the closure elements

(180, 180a, 180b, 181, 182) is held within the outer tube (101).

13. Smoke detector according to one of claims 11 to 12, wherein

the inner tube (102) has a plurality of openings (152) which form the plurality of second openings (152) of the second wall (121), and the outer tube (101) has a plurality of openings (151), which form the plurality of first openings (151) of the first wall (111), the openings (151) of the outer tube (101) having a first radial angular range with respect to the longitudinal axis of the outer tube (101) and the openings (152) of the inner tube ( 102) with respect to the longitudinal axis of the outer tube (101) point into a second radial angular range which does not overlap with the first radial angular range.

14. Vehicle, in particular rail vehicle, having at least one

Smoke detector (100, 200) according to one of the preceding claims.

15. The vehicle according to claim 14, wherein the smoke detector (100, 200) is arranged in a passenger compartment or in an installation space separate from the passenger compartment within the vehicle.