JP5210757B2 - smoke detector - Google Patents

Description

  The present invention relates to a smoke detector that detects a fire in response to smoke, and more specifically, applies light from a light emitting unit to smoke flowing into a smoke detection chamber, and receives scattered light scattered by smoke particles at the light receiving unit. The present invention relates to a photoelectric smoke detector that detects fire.

  Conventionally, a smoke detector is provided with a light emitting part in a detection chamber in which a plurality of labyrinth walls are provided, and a light receiving part is provided at a position where the light emitted from the light emitting part is not directly received, thereby providing a smoke sensitive area. It comprises (refer patent document 1). And as this smoke detector, the light receiving part receives the scattered light from the smoke flowing into the smoke sensing area through the smoke inlet formed in the gap between the labyrinth walls, and the threshold is set as a light reception signal. There is known a fire alarm device that outputs a fire alarm signal to give a fire alarm when it exceeds.

  The configuration of this conventional smoke detector will be briefly described with reference to FIG. The smoke detector 100 shown in FIG. 5 includes a light emitting unit 110 in which light emitting elements such as LEDs are disposed, and a light receiving unit 120 in which light receiving elements are disposed. The light emitting unit 110 and the light receiving unit 120 are arranged so that their optical axes intersect at an angle on the same horizontal plane. Thereby, the light emission part 110 irradiates light to the smoke particle which penetrate | invaded the smoke sensitive area | region S in the approximate center part of a detection chamber. And the light-receiving part 120 which received the scattered light scattered in the smoke sensitive area | region S converts the light quantity of the received light into a light reception signal.

The smoke detector further includes a light shielding wall (light shielding column) 130 for preventing light from directly entering the light receiving unit 120 from the light emitting unit 110. The length dimension and position of the light shielding wall 130 are as follows. It is stipulated so that it will not be an obstacle to floodlights. In addition, a plurality of labyrinth walls 140 that allow intrusion of smoke and prevent intrusion of outside light are provided around the detection chamber. A space between the plurality of labyrinth walls 140 forms a smoke inlet that allows smoke to flow into the detection chamber. The smoke detector 100 configured as described above is a combination of the photoelectric base 150 including the light emitting unit 110, the light receiving unit 120, and the light shielding wall 130, and the labyrinth cylinder 141 in which a plurality of labyrinth walls 140 are formed. Composed.
JP-A-9-231485

  By the way, a conventional smoke detector is installed on a ceiling surface or a wall surface of a room to be detected for detecting the amount of smoke in the room. In particular, when used as a fire alarm, heat convection occurs due to a fire, so by installing the smoke detector on the ceiling or wall of the room, the smoke flowing along the heat convection is It becomes easy to flow into. However, like the smoke detector 100 shown in FIG. 5, the conventional smoke detector is formed such that the optical axes of the light emitting unit 110 and the light receiving unit 120 intersect each other.

  Therefore, when the smoke detector 100 is installed on the wall surface, the smoke detector 100 is fixed in a state as shown in FIG. 6 in which the light emitting surface of the light emitting unit 110 and the light receiving surface of the light receiving unit 120 face the ceiling side. May be installed. FIG. 6 is a schematic view showing a state in the detection chamber of the smoke detector 100. As described above, when the smoke detector 100 is fixedly installed in the state shown in FIG. 6, the light emitting surface of the light emitting unit 110 and the light receiving surface of the light receiving unit 120 face the ceiling side. The dust that flows in may accumulate on the light emitting surface of the light emitting unit 110 or the light receiving surface of the light receiving unit 120. The accumulation of dust on the light emitting surface of the light emitting unit 110 or the light receiving surface of the light receiving unit 120 affects the amount of light emitted from the light emitting unit 110 or the amount of light received by the light receiving unit 120. The detection capability will be reduced.

  In view of such problems, the present invention proposes a smoke detector in which the installation position of the optical member configured in the smoke detection chamber is a position that prevents dust accumulation on the smoke amount detection portion of the optical member. For the purpose.

In order to achieve the above object, a smoke detector according to the present invention includes a detection chamber into which smoke flows, a light emitting unit that emits light into the detection chamber, and a light receiving unit that receives scattered light based on light from the light emitting unit. A smoke detector that receives the scattered light generated by irradiating the smoke flowing into the detection chamber with light from the light emitting unit, and detects the amount of light received by the light receiving unit as the amount of smoke. In the sensor, the light-receiving unit and the light-emitting unit are installed in the detection chamber, and the light-emitting surface of the light-emitting unit has a direction in which light is emitted in a horizontal direction or a direction closer to the floor side than the horizontal direction. orientation, and the light receiving surface of the light receiving section, faces the direction for receiving light from the floor surface than the horizontal direction or the horizontal direction, the sensitive smoke region where the scattered light generated by smoke flowing into the detection chamber Installed so that the light from the light emitting unit directly enters the light receiving unit. Further comprising an ingredient shielding wall to said detection chamber, the side surface of the sensitive smoke region side of the light shielding wall faces the floor surface side, the optical base on which the detection chambers are formed, abuts against the rear surface installation surface And a mark for recognizing the positions of the light receiving unit, the light emitting unit, and the light shielding wall in the detection chamber, which is inserted into an opening of a housing having a substantially disk-shaped base to be fixed. It is characterized by having been given.

  When such a smoke detector is installed on the wall surface, it is possible to prevent dust from accumulating on the light emitting surface of the light emitting unit by preventing the light emitting surface of the light emitting unit from facing the ceiling surface. Further, in the casing constituting the smoke detector, the direction of the light emitting surface of the light emitting unit may be recognized using a necessary structure such as an operation unit or a sound hole as a mark.

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  When such a smoke detector is installed on the wall surface, it is possible to prevent dust from accumulating on the light receiving surface of the light receiving unit by preventing the light receiving surface of the light receiving unit from facing the ceiling surface. Further, in the casing constituting the smoke detector, the direction of the light receiving surface of the light receiving unit may be recognized using a necessary structure such as an operation unit or a sound hole as a mark.

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  According to the present invention, it is possible to prevent the portion that most affects smoke detection in the optical member for detecting the amount of smoke from facing the ceiling surface. Thereby, since the accumulation of dust on the portion that most affects the smoke detection in the optical member for detecting the smoke amount can be prevented, the decrease in the smoke detection capability is suppressed. Furthermore, by preventing the dust from accumulating on the optical member, it is possible to suppress stray light generated when the dust is accumulated and reflection of light in an unintended direction.

<First Embodiment>
A smoke detector according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a state in the detection chamber when the smoke detector of the present embodiment is installed on a wall surface, and FIG. 2 is an exploded perspective view showing the configuration of the smoke detector of the present embodiment. In the schematic diagram shown in FIG. 1, the paper surface is a surface parallel to the wall surface, the upper side of the paper surface is the ceiling surface side, and the lower side of the paper surface is the floor surface. Moreover, in the schematic diagram shown in FIG. 1, in order to clarify the state of the detection chamber inside the smoke detector to be installed on the wall surface, a cross section of the detection chamber is shown. Further, in the present embodiment, a fire alarm having a configuration as shown in FIG. 2 that outputs a fire alarm will be described as an example of the smoke detector.

  As shown in FIG. 1, the smoke detector of the present embodiment includes an optical base 1 having a labyrinth wall 12 that forms a detection chamber, an insect repellent cover 3 that covers the outer peripheral side of the optical base 1, and an optical base. In order to protect the detection chamber formed on the table 1, a protective cover 5 for covering the outer periphery of the insect-proof cover 3 and a detection portion covered with the protective cover 5 are projected on the opposite side of the wall surface and fixedly installed on the wall surface. And a housing 6. The optical base 1 covered with the insect-proof cover 3 and the protective cover 5 includes a bottom plate 11 that forms a surface facing the wall surface, and an optical member is disposed on a surface opposite to the wall surface of the bottom plate 11. A detection chamber for detecting smoke is formed.

  The detection chamber on the bottom plate 11 of the optical base 1 includes a plurality of labyrinth walls 12 provided on the outer edge side of the bottom plate 11 and an accommodating portion 13 provided with a slit on the smoke sensing region S side inside the bottom plate 11. The light emitting unit 7 that houses the light emitting diode L, the light emitting unit 8 that houses the photodiode PD in the housing unit 14 that is provided with a slit on the inside of the smoke sensing region S inside the bottom plate 11, and the light emitted from the light emitting unit 7 It is constituted by a light shielding wall (light shielding column) 15 for preventing light from being directly received by the light receiving unit 8. In the detection chamber, the light emitting unit 7 and the light receiving unit 7 receive light so that the optical axis of the light irradiated by the light emitting diode L in the light emitting unit 7 and the optical axis of the light received by the photodiode PD in the light receiving unit 8 intersect each other. The installation position of the part 8 is determined.

  Further, the light emission range by the light emitting unit 7 is set by the slit provided on the light emitting surface side in the housing part 13 of the light emitting unit 7, and the slit provided on the light receiving surface side in the housing part 14 of the light receiving unit 8 by A light receiving range by the light receiving unit 8 is set. And the smoke sensitive area | region S formed in the position where the optical axis of the light light-emitted from the light emission part 7 and the optical axis of the light received by the light-receiving part 8 cross | intersect was provided in each of the accommodating parts 13 and 14. It is set in a region where the light emission range and the light reception range based on the size of the slit overlap. Further, a light shielding wall 15 is provided in a part of a region where the light emitting range by the light emitting unit 7 and the light receiving range by the light receiving unit 8 overlap, and the light shielding wall 15 is prevented from reaching the light receiving unit 8 directly from the light emitting unit 7. To do.

  When the detection chamber is formed on the optical base 1 in this way, the smoke flowing through the protective cover 5 and the insect-proof cover 3 passes through the smoke flow path formed by the gap between the labyrinth walls 12 that are provided around. , It is guided to the smoke sensitive area S formed in the area surrounded by the inner end of the labyrinth wall 12. At this time, since the light from the light emitting diode L is irradiated from the light emitting unit 7 toward the smoke sensing region S, scattered light is generated by the smoke guided to the smoke sensing region S. When the scattered light generated in the smoke sensing region S is received by the photodiode PD of the light receiving unit 8, an electric signal representing the amount of received light corresponding to the amount of smoke is output by the photoelectric conversion operation by the photodiode PD. .

  Further, a configuration when the smoke detector shown in FIG. 1 is a fire alarm will be described below with reference to an exploded perspective view of FIG. The smoke detector shown in FIG. 2 includes an optical base 1 in which a labyrinth wall 12, housing parts 13 and 14, and a light shielding wall 15 are erected on a bottom plate 11, optical system elements such as a light emitting diode L and a photodiode PD, and various circuit components. A circuit board 2 on which is mounted, an insect repellent cover 3 for preventing insects and dust from entering the detection chamber formed in the optical base 11, and a board for sounding an alarm when a fire is detected A speaker 4, a protective cover 5 that surrounds the speaker 4 and the insect-proof cover 3, and a housing 6 that houses the circuit board 2.

  The housing 6 has a substantially disk-shaped base 60 whose back surface is fixed in contact with the installation surface, and a ring-shaped side wall 61 protruding from the outer peripheral edge of the base 60 in a direction away from the installation surface. The side wall 61 has an end portion covered by the base 60 and a substantially disc-shaped main portion 62 covering the opposite end portion. The main portion 62 of the housing 6 has a shape that rises in the direction opposite to the installation surface from the connection portion with the side wall 61 toward the center, and a circular opening 63 is formed at the center portion. In addition, the operation button 64 electrically connected to the circuit mounted on the circuit board 2 is exposed to the outside from the surface around the opening 63 in the main portion 62 of the housing 6.

  The circuit board 2 is accommodated in the casing 6 having such a configuration, and the protective cover 5 in which the optical base 1, the insect-proof cover 3, and the speaker 4 are accommodated is provided in the opening of the casing 6. By being inserted into 63, it is assembled in a state protruding from the opening 63 of the main portion 62. The circuit board 2 installed inside the housing 6 is mounted with a light emitting diode L constituting a light emitting element and a photodiode PD constituting a light receiving element on a surface facing the optical base 1. A plurality of circuit components such as a control circuit for controlling the operation of each unit are mounted.

  The optical base 1 is provided with through holes at positions where the housing portions 13 and 14 of the bottom plate 11 are installed, and light emitting diodes L and photodiodes PD mounted on the circuit board 2 are inserted into the through holes provided in the bottom plate 11. The Thereby, the light emitting diode L and the photodiode PD are accommodated in the accommodating portions 13 and 14, respectively, and are shielded from external noise. In addition to the light emitting diode L and the photodiode PD, prism glasses for configuring the light emitting unit 7 and the light receiving unit 8 are provided in the housing units 13 and 14.

  The insect repellent cover 3 has a structure having an insect repellent net 33 so that insects, dust and the like do not enter the optical chamber constituted by the optical base 1. The outer frame 31 holding the insect screen 33 is configured such that the end on the side facing the optical base 1 is fitted with the peripheral wall of the optical base 1, and the end on the opposite side A round hole 32 for receiving the speaker 4 is provided. The speaker 4 is placed on the bottom 51 of the protective cover 5, and in a mounted state, the speaker 4 is fitted into the round hole 32 of the insect-proof cover. Further, the protective cover 5 is formed in a bottomed cylindrical shape, and a plurality of sound holes 51a for outputting the speaker 4 are provided in the bottom 51, and an opening 52a is formed in the peripheral wall 52 along the circumferential direction. The smoke flows from the opening 52a.

  When installing the smoke detector, first, the circuit board 2, the optical base 1, the insect-proof cover 3, the speaker 4, and the protective cover 5 are mounted on the base 60 and screwed with a fixing tool such as a screw. Thus, the base 60 is fixedly installed on the wall surface. Then, the base 60 is covered with a base cover by the main portion 62 and the side wall 61, and the cylindrical portion including the optical base 1, the insect-proof cover 3, the speaker 4, and the protective cover 5 is protruded from the opening 63. Put it in a state. At this time, in order to integrate the housing 6, the smoke detector is attached to the wall surface by locking the base 60 and the base cover.

  When the smoke detector is installed on the wall in this manner, as shown in FIG. 1, the smoke sensitive area S is disposed on the floor side with respect to the light emitting unit 7 and the light receiving unit 8 in the detection chamber. The installation direction of the circuit board 2 and the optical base 1 fixed to the base 60 is determined. That is, when the smoke detector is installed on the wall surface, the optical axis of the light emitted from the light emitting unit 7 is set to a direction parallel to the floor surface or inclined to the floor surface side. The position of the light-emitting unit 7 is determined so that does not face the ceiling surface. Similarly, for the light receiving unit 8, the optical axis of light incident on the light receiving unit 8 is set to be parallel to the floor surface or inclined to the floor surface side, and the light receiving surface of the light receiving unit 8 faces the ceiling surface. The position of the light receiving unit 8 is determined so as not to be present.

  Thus, in the detection chamber of the smoke detector installed on the wall surface, the positions of the light emitting unit 7 and the light receiving unit 8 so that the light emitting surface of the light emitting unit 7 and the light receiving surface of the light receiving unit 8 do not face the ceiling surface. Is determined. Thereby, it is possible to prevent dust from being deposited on each of the light emitting surface of the light emitting unit 7 and the light receiving surface of the light receiving unit 8, and as a result, a decrease in the amount of light emitted from the light emitting unit 7 and a decrease in the amount of light received by the light receiving unit 8. Each is prevented. Therefore, the fall of the smoke detection ability by the detection chamber in which the light emission part 7 and the light-receiving part 8 are provided can be suppressed.

Further, in the detection chamber of the smoke detector installed on the wall surface as shown in FIG. 1, the light shielding wall 15 is also installed on the ceiling side from the smoke sensing region S, and the side surface 15a of the light shielding wall 15 on the smoke sensing region S side is the floor. It is arranged to face the surface. This prevents dust from accumulating on the side surface 15a of the light shielding wall 15 on the side of the smoke sensitive area S, so that unintended reflection based on the accumulation of dust on the light shielding wall 15 can be prevented. The generation of stray light that affects S can be suppressed. Therefore, the deterioration of the smoke detection capability by the detection chamber is also suppressed by the arrangement position of the light shielding wall 15.

  As described above, when the smoke detector is installed on the wall surface, the positions of the light emitting unit 7, the light receiving unit 8, and the light shielding wall 15 are installed on the ceiling surface side of the smoke sensing region S in the detection chamber. The And in order to determine the position of each component in this detection chamber, an operator needs to recognize the installation position. Therefore, for example, when the installation direction of the housing 6 is determined by the installation direction of the base 60, a mark for recognizing the position of each component in the detection chamber in the smoke detector is given to the base 60. Also good. Thereby, since the operator can predict the direction of the smoke detector after the wall surface is installed based on the mark applied to the base 60, the light emitting unit 7, the light receiving unit 8, And the installation direction of the housing | casing 6 can be determined so that each position of the light-shielding wall 15 may be installed in the ceiling surface side rather than the smoke sensitive area | region S, respectively.

  Further, when the base cover by the side wall 61 and the main part 62 is rotatable with respect to the base 60 and the circuit board 2 and the optical base 1 are fixed to the base cover side, for example, from the main part 62 It is good also as what judges the installation direction of the detection chamber on the optical base 1 by using the operation button 64 to expose. In the example shown in FIG. 1, when the smoke detector is installed such that the operation button 64 is positioned on the left side of the detection chamber on the optical base 1, the light emitting unit 7, the light receiving unit 8, and the light shielding wall 15. These positions are respectively installed closer to the ceiling surface than the smoke sensitive area S. In addition to the operation button 64, when a light emitting diode or a liquid crystal panel is provided for displaying an alarm content, other components on the housing 6 are made to emit light, such as a light emitting diode or a liquid crystal panel. It is good also as a mark for recognizing each position of the part 7, the light-receiving part 8, and the light-shielding wall 15. FIG.

<Second Embodiment>
A smoke detector according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is an exploded perspective view showing the configuration of the smoke detector of the present embodiment, and FIG. 4 is a schematic cross-sectional view showing the state in the detection chamber when the smoke detector of the present embodiment is installed on a wall surface. . Also in this embodiment, a fire alarm having a configuration as shown in FIG. 3 that outputs a fire alarm will be described as an example of the smoke detector. In the smoke detector of the present embodiment, the same components as those in the smoke detector of the first embodiment (see FIGS. 1 and 2) are denoted by the same reference numerals, and detailed description thereof is omitted. To do.

  As shown in FIG. 3, the smoke detector of the present embodiment is fixed by being engaged with the outer periphery of the base 60 and the base 60 that is fixedly installed on the installation surface by being screwed with a screw or the like. The housing 6 is configured by the side wall 61 and a main portion 62 that serves as a top plate that covers the surface of the side wall 61 opposite to the base 60. Then, a button installation hole 65 into which the operation button 64 is inserted from the back side of the main portion 62 so that the operation button 64 is exposed on the front surface of the main portion 60, and a plurality of sound holes 51a at the installation relative position of the speaker 4. Are provided in the main portion 62.

  The side wall 61 is formed with an opening 66 on the outer peripheral surface thereof, and the end surface on the main portion 62 side is covered with a bottom plate 67. Since the speaker 4 is installed in a space surrounded by the bottom plate 67 and the main portion 62, this space functions as a resonance space by the speaker 4. And in order to comprise the detection chamber comprised on the optical base 1 in the base 60 side in the baseplate 67, the labyrinth wall 12 and the accommodating parts 13 and 14 which were provided in the baseplate 11 of the optical base 1 and A detection chamber insertion hole 68 into which the light shielding wall 15 is inserted is provided.

  In the smoke detector configured as described above, the optical base 1 is installed on the circuit board 2 so that the light emitting diode L and the photodiode PD mounted on the circuit board 2 can be accommodated in the optical base 1 respectively. It is accommodated in the parts 13 and 14. Then, the detection chamber having the light emitting portion 7 and the light receiving portion 8 on the bottom plate 11 of the optical base 1 is inserted into the detection chamber insertion hole 68 of the bottom plate 67. Thereby, the detection chamber of the optical base 1 is installed at the same height position as the opening 66 provided in the side wall 61 in the space on the base 60 side of the side wall 61. In addition, in the space on the side of the base 60 of the side wall 61, the insect-proof cover 3 that covers the outside of the labyrinth wall 12 and the storage portions 13 and 14 that constitute the detection chamber is installed.

  The smoke detector configured as described above includes a detection chamber inside the housing 6. Therefore, external smoke first flows into the housing 6 from the opening 66 provided in the side wall 61. At this time, since the detection chamber constituted by the optical base 1 is configured in a space where the height position with respect to the wall surface is the same as that of the opening 66 in the housing 6, the housing is opened from the opening 66 of the side wall 61. 6 Smoke that has flowed into the interior is guided to the detection chamber on the optical base 1. Then, the smoke that has reached the detection chamber of the optical base 1 inside the housing 6 passes through the smoke flow path formed by the gap of the labyrinth wall 12 and reaches the smoke sensing region S as in the first embodiment. Flows in. Therefore, the smoke flowing into the smoke sensing region S generates scattered light by the light from the light emitting unit 7, and the light receiving unit 8 that has received the scattered light outputs an electrical signal representing the amount of light received according to the amount of smoke. The

  Further, as described above, the smoke detector shown in FIG. 3 is inserted into the detection chamber insertion hole 68 from the bottom plate 67 toward the base 60 by connecting the optical base 1 connected to the circuit board 2 to the bottom plate. The insect-proof cover 3 installed on the base 60 side of 67 covers the detection chamber protruding from the bottom plate 67 toward the base 60 side. At this time, the circuit board 2 is installed on the main portion 62 side of the bottom plate 67 together with the operation button 64 and the speaker 4. By connecting the main part 62 to the side wall 61 so as to cover the side wall 61 having the bottom plate 67, the circuit board 2, the operation button 64, and the speaker 4 are arranged in the space covered by the main part 62 and the side wall 61. Is done.

  In this way, the base cover formed by connecting the side wall 61 and the main portion 62 is separated into two spaces by the bottom plate 67. The circuit board 2, the operation buttons 64 and the speaker 4 are installed in the space on the main portion 62 side of the bottom plate 67, while the optical base 1 and the side note cover 3 are in the space on the base 60 side of the bottom plate 67. Installed. The smoke detector is attached to the wall surface by the base cover formed by the side wall 61 and the main portion 62 being locked to the base 60 fixedly installed on the wall surface.

At this time, as shown in FIG. 4, the smoke detector of the present embodiment is similar to the smoke detector of the first embodiment (see FIG. 1). The installation direction of the optical base 1 with respect to the bottom plate 67 is determined so as to be arranged on the floor side with respect to each of the light receiving units 8. Further, the light shielding wall 15 is also installed on the ceiling side of the smoke sensing area S, and the side surface 15a on the smoke sensing area S side is arranged so as to face the floor surface. In FIG. 4, the side wall 61 of the housing 6 and the light emitting unit 7, the light receiving unit 8, and the light shielding wall 15 in the optical base 1 are schematically illustrated for the sake of simplicity.

In this way, when the wall surface of the smoke detector is installed, the light emitting unit 7, the light receiving unit 8, and the light shielding wall 15 in the detection chamber are each positioned so as to be installed on the ceiling side from the smoke sensing region S. As in the first embodiment, each of the light emitting surface of the light emitting unit 7, the light receiving surface of the light receiving unit 8, and the side surface 15a on the smoke sensing region S side of the light shielding wall 15 does not face the ceiling surface. Therefore, dust is prevented from accumulating on each of the light emitting surface of the light emitting unit 7, the light receiving surface of the light receiving unit 8, and the side surface 15a of the light shielding wall 15 on the smoke sensing region S side. Decrease in smoke detection capability can be suppressed.

  Also in the present embodiment, as in the first embodiment, in order to recognize the installation direction of the detection chamber on the optical base 1, as shown in FIG. 3, the base 60 fixed on the wall surface is marked. 69 may be displayed. Further, the installation direction of the detection chamber on the optical base 1 is recognized by the position of the component parts on the base cover such as the operation button 64 exposed on the main portion 62 or the sound hole 51a on the main portion 62. It is good.

  Furthermore, in this embodiment, the detection chamber formed on the optical base 1 installed in the space in the housing 6 surrounded by the side wall 61 is eccentric with respect to a plane parallel to the wall surface of the housing 6. In the case of being installed at the position, as shown in FIG. 4, the detection chamber of the smoke detector installed on the wall surface may be installed on the floor side. Thereby, in the detection chamber, the smoke sensing area S arranged on the floor side of each of the light emitting unit 7, the light receiving unit 8, and the light shielding wall 15 can be brought closer to the floor side opening 66 of the side wall 61. Therefore, when smoke generated by a fire flows along the wall surface from the floor toward the ceiling, a large amount of smoke can be guided to the smoke sensing region S in the detection chamber by the optical base 1 installed inside the housing 6.

  The present invention can be applied to a fire alarm that detects a fire based on the amount of smoke. In addition to this fire alarm, the present invention can also be applied to a detector that detects dust in an air cleaner or an air conditioner having an air cleaning function.

These are the schematic diagrams which show the state in the detection chamber when the smoke sensor of the 1st Embodiment of this invention is installed in the wall surface. These are the exploded perspective views which show the structure of the smoke detector of the 1st Embodiment of this invention. These are the exploded perspective views which show the structure of the smoke sensor of the 2nd Embodiment of this invention. These are the schematic diagrams which show the state of the detection chamber in a smoke detector, and the state in a detection chamber when installing the smoke sensor of FIG. 3 on a wall surface. FIG. 3 is an exploded perspective view showing an internal structure of a conventional smoke detector. FIG. 6 is a schematic view showing a state in the detection chamber when the smoke detector of FIG. 5 is installed on a wall surface.

DESCRIPTION OF SYMBOLS 1 Optical base 2 Circuit board 3 Insect-proof cover 4 Speaker 5 Protective cover 6 Case 7 Light-emitting part 8 Light-receiving part 11 Bottom plate 12 Labyrinth wall 13,14 Housing part 15 Light-shielding wall
15a Side surface 31 on the smoke sensitive area side of the light shielding wall 31 Outer frame 32 Round hole 33 Insect net 51 Bottom 51a Sound hole 52 Peripheral wall 52a Opening 60 Base 61 Side wall 62 Main part 63 Opening 64 Operation button 65 Button installation hole 66 Opening Part 67 Bottom plate 68 Detection chamber insertion hole L Light-emitting diode PD Photodiode

Claims (1)

A detection chamber into which smoke flows, a light emitting unit that emits light into the detection chamber, and a light receiving unit that receives scattered light based on light from the light emitting unit, and the smoke that has flowed into the detection chamber In the smoke detector that receives the scattered light generated by irradiating light from the light emitting unit, and detects the amount of light received by the light receiving unit as the amount of smoke,
The light receiving unit and the light emitting unit are installed in the detection chamber,
The light emitting surface of the light emitting unit faces the horizontal direction or the direction of irradiating light in a direction that is closer to the floor surface than the horizontal direction, and the light receiving surface of the light receiving unit is the floor surface side of the horizontal direction or the horizontal direction Facing the direction to receive light from
Is installed in sensitive smoke area light scattered by smoke flowing into the sensing chamber occurs, further comprising a light shielding wall for preventing direct light incident to the light receiving portion of the light from the light emitting portion in the detection chamber, The side surface of the light shielding wall on the smoke sensitive area side faces the floor surface side,
The optical base on which the detection chamber is formed is inserted into an opening of a housing having a substantially disk-shaped base that is fixed with the back surface being in contact with the installation surface, and the base includes the detection chamber. The smoke detector is characterized by being provided with a mark for recognizing the positions of the light receiving portion, the light emitting portion, and the light shielding wall .

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