JP5885786B2 - smoke detector - Google Patents

Description

  The present invention relates to a smoke detector that detects the generation of smoke during a fire.

  The smoke detector includes, for example, a light diffusion type sensor unit having a light emitting unit and a light receiving unit, and the light receiving unit detects light from the light emitting unit scattered by the smoke flowing into the sensor unit. It senses the existence of However, the smoke detector installed on the wall surface is particularly in an environment in which foreign matters such as dust easily enter from above. If dust or the like enters the inside of the sensor unit, scattered light may be generated even when smoke is absent, and there is a risk of false detection.

Therefore, in the smoke detector described in Patent Document 1, the reflector that reflects the light emitted from the light emitting unit toward the smoke sensing region including the intersection between the axes of the light emitting unit and the light receiving unit, In the installation state in which the plane including the axis of the light emitting unit and the axis of the light receiving unit is vertical, the gap adjacent to the upper side of the reflecting plate and the space behind the reflecting plate are arranged opposite to the light emitting unit. A dust introduction path is provided for communication connection without passing through the reflection surface of the reflection plate.

  In the smoke detector described in Patent Document 1, the light emitted from the light emitting part is reflected toward the smoke sensing area by entering the reflector opposite to the light emitting part, and enters the smoke sensing area. The brightness or amount of light scattered by the smoke increases. Even if dust or the like enters from a gap adjacent to the upper side of the reflecting plate, the dust moves to the space behind the reflecting plate through the dust introduction path, so that it is difficult for the dust to adhere to or accumulate on the reflecting surface. Thereby, it was supposed that it can suppress that a sensing ability falls by the dust etc. which penetrate | invaded in the sensor part.

JP 2010-20470 A

  However, the smoke detector described in Patent Document 1 is a technique that prevents dust from entering the smoke detection area even if dust enters the sensor unit. In addition, Patent Document 1 suggests that a light receiving unit having a large horizontal projection area is provided on the upper side to reduce dust intrusion into the sensor unit, but as long as there is a smoke inlet opening upward. It does not prevent dust from entering the inside of the sensor unit.

  In view of the above circumstances, an object of the present invention is to provide a smoke detector having a structure in which foreign matter such as dust is less likely to enter a sensor unit.

A first characteristic configuration of a smoke detector according to the present invention is a smoke detector that is used by being attached to a wall surface, and includes a base portion that can be attached to the wall surface, and a cover portion that is attached to the base portion. A case part that allows inflow of smoke from a surface, and a sensor part that is accommodated in the case part and that can sense the inflowing smoke, and at least one of the cover part and the base part includes the case A smoke guide part for guiding smoke flowing into the sensor part to the sensor part, and at least a part of the smoke guide part is located above the sensor part when the case part is attached to the wall surface The smoke guiding portion disposed at a position above the sensor portion is disposed inside the case portion, is formed horizontally along the side peripheral surface of the sensor portion, and falls from above. Dust coming It lies in having a horizontal portion to be.

According to this configuration, the sensor unit is housed in the case unit, and the smoke guiding unit that guides smoke to the sensor unit is located above the sensor unit. Therefore, dust falling from above can be reliably deposited on the horizontal portion of the upper surface of the smoke guiding portion, and dust can be prevented from entering the sensor.
Moreover, since the said smoke guidance part has the horizontal part formed horizontally along the side surrounding surface of the said sensor part, the horizontal projection area of a smoke guidance rib becomes large, and prevents the penetration | invasion of dust etc. in a sensor part. Certainty increases.

A second characteristic configuration of the smoke detector according to the present invention is that the smoke guiding portion disposed at a position above the sensor portion includes an inclined portion extending obliquely upward from the horizontal portion. .

  In this configuration, since the smoke guiding portion is inclined with respect to the vertical direction, the horizontal projection area of the smoke guiding portion is increased. Thereby, the certainty which prevents the penetration | invasion of the dust etc. in a sensor part increases.

A third characteristic configuration of the smoke detector according to the present invention is the smoke induction provided with a plurality of smoke inlets capable of introducing smoke on a side peripheral surface of the sensor unit, and disposed at a position above the sensor unit. The horizontal portion of the portion is configured to be positioned above the smoke introduction port that opens toward the uppermost side.

With this configuration, even if dust or the like enters the case from above, there is a high probability that it will accumulate on the horizontal part of the top surface of the smoke guiding part, and it will reach the smoke inlet that opens to the uppermost side. It becomes difficult.

(A) is a perspective view from the front direction of a smoke detector. (B) is a perspective view from the back direction of a smoke sensor. FIG. 4 is a cross-sectional view of the smoke detector as viewed from the back. FIG. 3 is an exploded perspective view from the back side of the smoke detector. FIG. 3 is a perspective view from the back side of the smoke detector with the rear case removed. These are the end views of the VV direction in FIG. These are sectional drawings of the VI-VI direction in FIG. These are sectional drawings of the VII-VII direction in FIG. These are perspective views which show the relationship between the base fixed to the wall surface, and a case. FIG. 4 is a rear view when the case is supported on the base. FIG. 3 is a top view showing the flow of smoke with respect to the smoke detector installed on the wall surface. FIG. 11 is a schematic diagram showing the flow of smoke in FIG. 10.

  Hereinafter, an embodiment of a smoke detector according to the present invention will be described with reference to the drawings.

[About overall configuration]
As shown in FIGS. 1 and 2, the smoke detector allows the inflow of smoke from the side peripheral surface and is a square, that is, a non-circular case portion (hereinafter referred to as “case 1”) when viewed from the front. ), A photoelectric sensor unit (hereinafter referred to as “sensor 3”) that can be accommodated in the case part and can detect the smoke that flows in, and a circular shape that is smaller than the square shape of the case part in front view, An attachment base portion (hereinafter referred to as “base 4”) that can be fixed to a wall surface and to which a case portion can be attached is provided.

  The sensor 3 detects the smoke flowing into the case 1 and emits an alarm sound from the speaker 5 when the smoke concentration exceeds a preset threshold value. To stop the alarm sound, the alarm sound can be stopped by pressing an alarm stop button 6 disposed on the surface of the case 1. If the alarm is installed at a high place and the alarm stop button 6 is not reachable, the alarm sound is stopped even if the alarm stop string 7 that can be hung down from the case 1 is pulled.

  Hereinafter, on the premise that the smoke detector is installed on the wall surface, the side opposite to the wall surface is defined as the front side or the front side, and the wall surface side is defined as the back side or the rear side. Therefore, “front view” according to the present invention refers to viewing the smoke detector from the surface side. As for the vertical direction, the description will be made assuming that the upper direction of the drawing in FIGS. 1 and 2 is “up” of the smoke detector and the lower direction is “down”. In FIG. 3, the left direction of the paper surface is “upper” of the smoke detector, the lower right direction of the paper surface is “upper” in FIG. 4, and the upper direction of the paper surface is “upper” in FIG. In FIG. 7, the front direction on the paper is “up”, in FIG. 9, the upper direction on the paper is “up”, and in FIG. 10, the front side on the paper is “up”.

[Case Overview]
As shown in FIGS. 3 and 5, the case 1 includes a base portion on the back side (hereinafter referred to as “rear case 1a”), a cover portion on the front side (hereinafter referred to as “front case 1c”), and a rear case. And a partition portion (hereinafter referred to as “intermediate case 1b”) that partitions the internal space of the case 1 surrounded by 1a and the front case 1c in the front-rear direction. The front case 1c, the rear case 1a, and the intermediate case 1b are made of resin and are manufactured by injection molding. The case 1 houses a sensor 3, a substrate 2, a speaker 5, an alarm stop button 6, and the like.

  As shown in FIG. 5, the surface of the front case 1c is substantially flat as a whole, with the outer peripheral portion being slightly inclined toward the back side. The outer peripheral end of the front case 1c is raised to the back side. The outer peripheral end of the intermediate case 1b is raised to the surface side. Furthermore, the outer peripheral end of the rear case 1a is also raised to the surface side, and the rising portion constitutes the side circumferential surface of the case 1. A grid-like smoke inlet 11 is formed at the rising portion of the rear case 1a, and the inflow of smoke into the case 1 is allowed. The outer peripheral end of the rear case 1a is slightly raised on the back side, and when the case 1 is attached to the base 4, a part of the base 4 is accommodated in this rising portion. The front case 1c, the rear case 1a, and the intermediate case 1b become smaller in front view shape, and the rising portion of the rear case 1a is inserted into the gap between the rising portion of the front case 1c and the rising portion of the intermediate case 1b. .

[Summary of sensor]
As shown in FIG. 2, the sensor 3 has a cylindrical shape and is arranged in parallel with a plurality of smoke inlets 3 c provided on the side peripheral surface through which a smoke can be introduced and a gap so as to block light from the outside. A plurality of labyrinth-shaped walls, a light emitting unit 3a that irradiates light inside the sensor 3, and a light receiving unit 3b that senses light from the light emitting unit 3a scattered by the smoke flowing into the sensor 3; It is equipped with. Since this sensor 3 is already known, the mechanism of smoke detection will not be described here. An insect screen 3d is provided on the outer peripheral side of the smoke inlet 3c.

[Outline of substrate]
As shown in FIG. 3, a sensor 3 and a power connector 2 c are disposed on the substrate 2, and a speaker 5 is connected to the substrate 2. The board 2 is printed with an electric circuit (not shown) and provided with electronic parts (not shown), and controls smoke detection, alarm sound generation, and the like. A smoke adjusting unit 2a is provided on the same surface of the substrate 2 as the surface on which the sensor 3 is disposed. Via the smoke adjustment unit 2a, signals and data can be sent from the outside to the substrate 2 side, and signals and data can be read from the substrate 2 side to the outside. Used for adjustment.

  Further, the same surface as the surface on which the sensor 3 is disposed in the substrate 2 is provided with an automatic test unit 2b that controls the automatic test function. The automatic test function is a “test function related to a fire alarm facility by a device that can automatically confirm that the function related to the fire alarm facility is properly maintained” Ministerial Ordinance, Article 2, Item No. 12) The automatic fire testing part 2b stipulates that the product must be easily accessible from the outside without disassembling the product. In the product state, a metal piece is brought into contact with the automatic test unit 2b from the outside and the test terminal is short-circuited, thereby generating the same state as the failure and confirming whether the failure is properly recognized.

[Assembly of the case]
The assembly outline of the smoke detector and the relative positional relationship of each member will be described. First, as shown in FIGS. 3 and 5, the alarm stop button 6 is dropped from the back side into the opening for the alarm stop button 6 formed in the front case 1c, and is supported by the front case 1c so as to be swingable about the left and right direction as an axis. To do. The alarm stop button 6 is provided with a string hooking portion 6a that is erected in the rear direction, and the alarm stop pull string 7 can be applied or removed. The alarm stop button 6 swings to the back side when it is pressed or the alarm stop pull string 7 is pulled, and a switch for alarm sound stop (not shown) disposed on the front side of the board is provided. It is possible to push.

  Next, as shown in FIGS. 3 and 5, the substrate 2 is fitted into a predetermined position of the front case 1 c together with the speaker 5 with the surface on which the sensor 3 is disposed facing the back side. Subsequently, the intermediate case 1 b is fitted into the front case 1 c so as to cover the substrate 2. Protrusions (not shown in the figure) projecting inward are formed on the inner side surfaces of two arbitrary corners on the inside surface of the front case 1c. On the outer surface of the intermediate case 1b, protrusions (not shown) protruding outward are formed corresponding to the protrusions of the case 1c. When the intermediate case 1b is forcibly pushed in until the leading end surface of the rising portion of the intermediate case 1b contacts the back surface of the front case 1c, both protrusions get over each other and engage. Thereby, the intermediate case 1b is fixed to the front case 1c, and is integrated with the front case 1c. As shown in FIG. 3, an opening having substantially the same diameter as the sensor 3 is formed in the intermediate case 1 b so that the intermediate case 1 b does not interfere with the sensor 3. After the arrangement of the intermediate case 1b, as shown in FIG. 4, the sensor 3 protrudes to the back side of the intermediate case 1b, but there is no gap between the sensor 3 and the opening of the intermediate case 1b. A space between the front case 1c and the intermediate case 1b is a “substrate arrangement space SA” according to the present invention. That is, the substrate 2 and the speaker 5 are arranged in the substrate arrangement space SA.

  Next, as shown in FIG. 5, the rising portion of the rear case 1a is fitted between the rising portion of the front case 1c and the rising portion of the intermediate case 1b so as to cover the intermediate case 1b and the sensor 3. The space between the rear case 1a and the intermediate case 1b is the “smoke induction space SB” according to the present invention. That is, the sensor 3 is disposed in the smoke guiding space SB that is separated from the substrate placement space SA by the intermediate case 1b. The smoke inlet 11 is largely open to the smoke induction space SB, and the smoke can smoothly flow into the smoke induction space SB.

As shown in FIG. 3, the front case 1c, the intermediate case 1b, and the rear case 1a are provided with a boss portion 1d for standing through a screw as a “fixing tool” at the same position in a front view. . When the intermediate case 1b is fitted into the front case 1c, the boss 1 of the intermediate case 1b
d covers the boss 1d of the front case 1c. When the rear case 1a is further fitted, the tip of the boss 1d of the rear case 1a and the tip of the boss 1d of the intermediate case 1b are brought into contact with each other. In this way, the boss 1d of the front case 1c, the boss 1d of the intermediate case 1b, and the boss 1d of the rear case 1a are integrated to form a boss 1d extending from the front case 1c to the rear case 1a. Is done. When a screw is tightened into the boss 1d from the rear side of the rear case 1a, the rear case 1a is fixed to the front case 1c, and the intermediate case 1b is also completely fixed in the case 1, and the case 1 is assembled.

  As described above, as shown in FIG. 1, the case 1 having a square shape in the front view and a square shape in the side view is completed. As described above, the substrate 2 is disposed on the front case 1c, and the sensor 3 is disposed near the rear case 1a, thereby reducing the thickness of the smoke detector in the front-rear direction, and reducing the thickness of the smoke detector. can do.

[Internal structure of the case and smoke induction rib]
The internal structure of case 1 will be described. As shown in FIG. 2, smoke guiding ribs 12 and 31 are formed in the case 1 as “smoke guiding portions” for guiding the smoke flowing in from the smoke inlet 11 to the smoke inlet 3 c of the sensor 3. . The smoke inlets 3c are provided substantially uniformly on the side peripheral surface of the sensor 3 so that the sensor 3 can detect the smoke regardless of the direction of 360 ° smoke flowing into the case 1. However, in addition to the sensor 3, the boss portion 1 d, the battery housing portion 15, the external output mechanism housing portion 14, and the like, which are described later, also exist in the internal space of the case 1, and there is a possibility that the smoke does not flow smoothly. The smoke guide ribs 12 and 31 guide the smoke so that it can smoothly reach the smoke inlet 3c while avoiding the boss portion 1d and the like, regardless of the direction of the 360 ° smoke flowing into the sensor 3. . The smoke guide ribs 12 and 31 are provided to extend in the front-rear direction between the intermediate case 1b and the rear case 1a. The smoke guide ribs 12 and 31 also serve to partition the smoke guide space SB into a space in which smoke circulates, the battery housing portion 15 and the like.

  As shown in FIG. 5, the smoke guide ribs 12 and 31 are formed upright on the back side of the intermediate case 1b toward the back side, and formed upright on the front side of the rear case 1a toward the front side. There are 12 things. In this way, the smoke guide ribs 12 and 31 are dispersed in the intermediate case 1b and the rear case 1a, thereby preventing the injection molding from becoming complicated. In the member on the side where the smoke guide ribs 12 and 31 are not formed, the portion where the tip portions of the smoke guide ribs 12 and 31 abut is recessed according to the shape of the tip portion. That is, it has an inlay structure. When the smoke guide ribs 12 and 31 are fitted into the recesses 32 and 13, a gap is less likely to be generated compared to when the smoke guide ribs 12 and 31 are merely abutted, and the smoke guide ribs 12 and 31 having a cantilever structure are formed. The free end (tip) is held and the smoke guiding ribs 12 and 31 are positioned and stabilized.

  When the smoke detector is installed on the wall surface as in the present embodiment, the smoke inlet 11 faces upward, so that foreign matter such as dust may enter the case 1 from above. If the foreign matter passes through the wall portion of the labyrinth structure from the smoke inlet 3c and enters the sensor 3, the light from the light emitting portion 3a is scattered by the foreign matter, and there is a possibility that a false alarm is issued. However, if the foreign matter is large, it will not be caught by the insect screen 3d and enter the sensor 3.

  Therefore, as shown in FIG. 2, the boss 1d, the smoke guiding rib, and the external output mechanism accommodating portion 14 are appropriately arranged above the smoke inlet 3c that opens upward in the smoke inlet 3c. Even if dust or the like enters the case 1 from above, there is a high probability of accumulation on the upper surfaces of these members, and it is difficult to reach the smoke inlet 3c. In particular, the smoke inlet 3c located on the uppermost side has a high opening ratio with respect to the upper side, so that there is a high risk of dust and the like entering. Then, about the smoke induction rib located above the adjacent smoke introduction port 3c located on the uppermost side, from the horizontal portion 12a along the side peripheral surface of the sensor 3 between the adjacent smoke introduction ports 3c, and the horizontal portion 12a And an inclined portion 12b extending obliquely upward. As a result, while the smoke flowing into the case portion is smoothly guided to the smoke inlet 3c, the horizontal projection area of the smoke guide rib is increased, and the certainty of preventing entry of dust or the like into the sensor portion is increased.

  As shown in FIG. 8, the rear case 1a has an external output mechanism accommodating portion 14 that accommodates an external output mechanism that outputs smoke detection information to the outside, and a battery accommodating portion 15 that accommodates a battery as a driving power source for the smoke detector. And are formed. The external output mechanism housing part 14 and the battery housing part 15 are bottomed recessed parts in which the rear case 1a is recessed into the front side. As shown in FIG. 2, a part of the side wall of the external output mechanism housing part 14 and a part of the side wall of the battery housing part 15 also function as a “smoke guiding part” according to the present invention. As shown in FIG. 6, the distal end portion of the external output mechanism housing portion 14 is in contact with the intermediate case 1 b and has the above-described spigot structure. The battery accommodating portion 15 needs a depth in the front-rear direction to accommodate the battery, and cannot be accommodated by the height in the front-rear direction between the intermediate case 1b and the rear case 1a. Therefore, as shown in FIG. 2, the intermediate case 1b is provided with an opening that matches the outer shape of the battery housing portion 15, and the battery housing portion 15 is fitted into the opening.

  As described above, when the intermediate case 1b is fitted into the front case 1c, the sensor 3 is positioned. Therefore, the smoke inflow performance can be adjusted in this state. Therefore, as shown in FIG. 4, a smoke adjustment hole 33 as an “opening” is formed at a location facing the smoke adjustment portion 2 a in the intermediate case 1 b. Thereby, smoke adjustment is possible in the middle of product manufacture. The smoke adjustment hole 33 communicates the substrate arrangement space SA and the smoke induction space SB, and is configured such that the smoke adjustment hole 33 opens to the isolation region SP surrounded by the smoke induction rib. In the present embodiment, as shown in FIGS. 2 and 6, the bottom portion of the external output mechanism accommodating portion 14 that also serves as the smoke guiding portion is configured to block the smoke adjusting hole 33. Thereby, after adjusting the smoke inflow performance, the smoke adjustment hole 33 is closed only by assembling the rear case 1a. As a result, even if a foreign matter such as a water droplet or an insect enters the smoke guiding space SB from the smoke inlet 11, it cannot reach the smoke adjusting hole 33 and does not contact the substrate 2. Therefore, failure of the substrate 2 can be prevented.

  Similarly, as shown in FIG. 2, the power connector 2c that dislikes contact with foreign matter is disposed in an isolation region SP different from the external output mechanism housing portion 14 to prevent contact with foreign matter. Therefore, failure of the substrate 2 can be prevented.

  As described above, the automatic test unit 2b must be able to be easily contacted from outside without disassembling the product. Therefore, the automatic test hole 34 is formed in the intermediate case 1b at a location facing the automatic test portion 2b, and the automatic test hole 17 is also formed in the rear case 1a on the extension line in the front-rear direction. Thereby, it is possible to confirm the automatic test function after product assembly. The automatic test hole 34 communicates the substrate arrangement space SA and the smoke guiding space SB. As shown in FIG. 7, the automatic test hole 34 stands so that the outer periphery of the automatic test hole 34 of the intermediate case 1b contacts the substrate 2. The range of the substrate 2 exposed to the smoke induction space SB is minimized.

[About the base]
As shown in FIG. 8, the base 4 is fixed to the wall surface prior to the case 1. The base 4 is made of resin and is manufactured by injection molding. As shown in FIG. 9, the base 4 is circular and has a size inscribed in the square shape of the rear case 1a. That is, it can be said that the case 1 is made compact by making the case 1 smaller than the base 4, and the case 1 is stabilized by making the base 4 largest for the case 1. It can be said that this is a structure that can be supported. Protrusions 41 projecting radially outward are formed at four locations on the outer periphery of the base 4. As shown in FIG. 8, the protrusion 41 is formed with a hole through which a fixture, for example, a gypsum board pin P can be inserted, and the base 4 is attached to the wall surface of the gypsum board via the four protrusions 41. be able to. The base 4 is also formed with a screw hole 44, which can be attached with a screw or the like.

[Attaching the case to the base]
A procedure for attaching the case 1 to the base 4 will be described. As shown in FIG. 8, a guided portion 16 that protrudes toward the back side is integrally formed at the center portion of the rear case 1 a, and a guide portion 42 that is recessed at the back side is integrally formed at the center portion of the base 4. The guided portion 16 has a circular shape when viewed from the front, and has two outer peripheral portions projecting radially outward. The guide part 42 is formed in a shape that follows the shape of the guided part 16, and has a shape in which the guide part 42 can be fitted. When the case 1 is attached to the base 4, the circular portion of the base 4 is hidden behind the case 1, but only the protrusion 41 is visible, and the center of the base is determined from the plurality of protrusions 41. it can. Furthermore, since the guided portion 16 is configured to fit into the guide portion 42, the case 1 and the base 4 can be easily aligned. When the guided portion 16 is fitted into the guide portion 42, both are positioned. Thereafter, when the case 1 is rotated according to the guidance of the guide portion 42, the engagement hook 18 provided on the rear outer peripheral portion of the rear case 1 a is engaged with the engagement hook 43 provided on the front outer peripheral portion of the base 4. The case 1 can be attached to the base 4. When the case 1 is attached to the base 4, as shown in FIG. 5, a part of the base 4 protrudes from the rear case 1 a to the back side, that is, the wall surface side in a side view.

  In this way, the smoke detector is installed on the wall surface. In addition, since case 1 is square shape by front view, the outer periphery four sides of case 1 become parallel or perpendicular | vertical with respect to the ceiling surface and floor surface of installation space. Therefore, it is easy to become familiar with the installation space as compared with the case of the circular shape.

[Inflow of smoke into the smoke detector]
The flow of smoke into the smoke detector will be described. For convenience of explanation, a case where the flow of smoke is in the horizontal direction will be described. As described above, when the case 1 is attached to the base 4, a part of the base 4 protrudes from the rear case 1a in a side view. That is, as shown in FIG. 10, when the smoke detector is installed on the wall surface W, the case 1 is slightly lifted from the wall surface W. For this reason, the smoke along the wall surface where the airflow velocity has fallen due to friction loss due to the wall surface W flows into the space between the rear case 1a and the wall surface W, and the smoke away from the wall surface W where the airflow velocity does not drop remains as the smoke flow It flows into the inlet 11. Moreover, since the base 4 is circular, the smoke along the wall surface is smoothly guided along the side surface of the base 4 to the downstream side in the airflow direction. Although some smoke collides with the side surface of the base 4 and the turbulence of the air flow occurs, the base 4 is smaller than the case 1 in a front view, and the side surface of the base 4 and the smoke inlet 11 are separated from each other. There is little effect on the smoke flowing in. Therefore, by using a thin smoke detector as described above, the responsiveness of the smoke detector is not impaired even if the smoke inlet 11 is closer to the wall surface than in the past.

[Another embodiment]
(1) In the above-described embodiment, the case portion 1 has a square shape, but is not limited to this shape, and may be any non-circular shape. The case portion 1 may be, for example, another polygonal shape such as a triangular shape or a non-linear shape such as an elliptical shape. In addition, in the case of a polygonal shape including a square shape, the corners of the front view may be chamfered.
(2) In the above-described embodiment, the substrate 2 is disposed between the front case 1c and the intermediate case 1b, but is not limited thereto, and is disposed between the rear case 1a and the intermediate case 1b. There may be. In this case, the rear case 1a is assembled.

  The present invention can be applied to a smoke detector that is installed on a wall surface and detects smoke by a photoelectric sensor.

1 Case (case part)
1a Rear case (base)
1c Front case (cover part)
1d Boss part 3 Sensor (Sensor part)
12 Smoke induction rib (smoke induction part)
31 Smoke induction rib (smoke induction part)
W wall surface

Claims (3)

A smoke detector that is attached to a wall and used.
A base part that can be attached to the wall surface, and a cover part that is attached to the base part, and at least a case part that allows inflow of smoke from the side peripheral surface;
A sensor part housed in the case part and capable of sensing the inflowing smoke,
At least one of the cover part and the base part includes a smoke guiding part that guides smoke flowing into the case part to the sensor part,
Arranging at least a part of the smoke guiding part at a position above the sensor part when the case part is attached to a wall surface,
The smoke guiding portion disposed at a position above the sensor portion is disposed inside the case portion and is formed horizontally along the side peripheral surface of the sensor portion, and removes dust falling from above. A smoke detector with a horizontal part to be deposited.   2. The smoke detector according to claim 1, wherein the smoke guiding portion disposed at a position above the sensor portion includes an inclined portion extending obliquely upward from the horizontal portion.   A plurality of smoke inlets capable of introducing smoke are provided on the side peripheral surface of the sensor unit, and the horizontal part of the smoke guiding unit arranged at a position above the sensor unit opens toward the uppermost side. The smoke detector according to claim 1 or 2, wherein the smoke detector is configured to be positioned above the smoke inlet.

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