JP6689693B2 - Photoelectric smoke detector - Google Patents

Description

  The present invention relates to a photoelectric smoke detector that detects smoke by detecting light scattered by smoke.

  The photoelectric smoke detector, for example, as in the "scattered light smoke detector" disclosed in Patent Document 1, facilitates the inflow of smoke from the outside and blocks the light from the outside, and the smoke detecting chamber is provided at the center. And a light emitting element and a light receiving element that are arranged so that their optical axes intersect with each other in the smoke detection chamber formed by the labyrinth member.

The labyrinth member in the above-mentioned "scattered light smoke detector" has a function of forming a smoke detection chamber on the inner peripheral side thereof and blocking light from the outside while allowing smoke to flow in.
In addition to smoke, there may be cigarette smoke, steam, or other suspended matter that is not originally a detection target in the space where the scattered light smoke detector is installed. When the two functions of forming a smoke chamber are provided, it is difficult to detect smoke and not detect other suspended matter.

  Therefore, by providing a smoke introduction part at the bottom and a smoke detection chamber above the smoke introduction part, it is possible to distinguish smoke from other suspended matter and to introduce only smoke into the smoke detection chamber. A sensor is disclosed in Patent Document 2.

Patent Document 2 includes a conventional example shown in FIG. 1 of Patent Document 2 and an invention example of Patent Document 2 shown in FIGS. 3 to 5.
In the structure shown in FIG. 1, a guide column for guiding smoke into the smoke detecting chamber is provided at the center of the smoke introducing portion.

  In the case shown in Fig. 1, since the guide pillar extends to the vicinity of the smoke detecting section, there is a problem that suspended matter other than smoke due to a fire is also introduced into the smoke detecting section, causing false detection. As a solution to the above problem, the ones shown in FIGS. 3 to 5 have been proposed.

  In the photoelectric smoke detector shown in FIGS. 3 to 5, the smoke introducing portion is formed by a cylindrical smoke introducing box, and a mountain-shaped portion protruding upward is formed in the center of the smoke introducing box. It is provided such that the top of the mountain-shaped portion is located below the smoke detection chamber.

  When smoke from a fire flows into such a smoke introduction box, it is introduced into the smoke detection chamber by convection because it is accompanied by temperature, but other airborne particles without temperature do not cause convection. It is not introduced into the sensing area of the smoke detection room, and it is said that false detection will not occur.

JP-A-6-76182 JP-A-55-7658

  However, since steam is accompanied by temperature like fire smoke, it convects (rises) like fire smoke. Therefore, the technology disclosed in Patent Document 2 cannot accurately distinguish fire smoke and steam. .

  The present invention has been made to solve the above problems, and an object thereof is to obtain a photoelectric smoke detector that does not cause erroneous detection by distinguishing it from smoke of fire even if it is airborne particles accompanied by temperature such as steam. I am trying.

(1) A photoelectric smoke detector according to the present invention includes a smoke detecting section for detecting smoke by detecting scattered light due to smoke, and a smoke detecting section provided below the smoke detecting section for attenuating external light and flowing in. And a smoke guiding unit for introducing the smoke into the smoke detecting unit, wherein the smoke guiding unit has a smoke flow path formed by combining vertically facing parts. The smoke flow passage includes a first smoke flow passage that guides the introduced smoke inward, and a smoke that is formed on an inner peripheral side of the first smoke flow passage and that passes through the first smoke flow passage. It has a second smoke flow path that guides obliquely upward toward the smoke detection section, and the width of the flow path in the height direction is narrowed at the boundary between the first smoke flow path and the second smoke flow path. It is characterized in that a narrow portion is formed.

(2) Moreover, in the thing described in said (1), the said 1st smoke flow path is characterized by gradually narrowing the flow path width inward.

(3) Moreover, in the thing as described in said (1) or (2), the member which forms the lower surface of the said 2nd smoke flow path does not extend the height of the top part to the said smoke detection part. It is characterized in that it is set to a position below the smoke detector.

(4) Further, in any one of the above (1) to (3), a slit is formed on a wall surface of the first smoke flow path and / or the second smoke flow path. .

(5) Further, in any one of the above (1) to (4), a guide member for guiding the inflowing smoke toward the second smoke flow path is provided in the first smoke flow path. It is characterized by that.

(6) Further, in the structure described in (5) above, the guide member is composed of a plurality of plate-shaped members that are erected radially in the circumferential direction of the first smoke flow path. .

The photoelectric smoke detector according to the present invention is a smoke detecting section for detecting smoke by detecting scattered light due to smoke, and a smoke detecting section provided below the smoke detecting section for attenuating external light and for collecting inflowing smoke. A photoelectric smoke detector having a smoke guiding portion to be introduced into the smoke detecting portion,
The smoke guiding portion has a smoke flow path formed by combining vertically facing parts, and the smoke flow path includes a first smoke flow path for guiding the introduced smoke inward and the first smoke flow path. 1 has a second smoke flow path formed on the inner peripheral side of the smoke flow path and guiding smoke passing through the first smoke flow path obliquely upward toward the smoke detecting section side,
The steam that has flowed into the first smoke flow path is formed by forming the narrowest part in which the flow width in the height direction is narrowed at the boundary between the first smoke flow path and the second smoke flow path. Since particles collide with each other when passing through the narrowest part and the particle size becomes large, the inclined surface of the second smoke flow path cannot be raised and is not introduced into the smoke detecting part. , False detection is prevented.

It is a longitudinal cross-sectional view of the photoelectric smoke detector according to the first embodiment of the present invention. FIG. 2 is an exploded view of the vertical sectional view shown in FIG. FIG. 3 is an exploded perspective view of the photoelectric smoke detector according to the first embodiment of the present invention viewed from a front oblique direction. FIG. 3 is an exploded perspective view of the photoelectric smoke detector according to the first embodiment of the present invention as seen from a rear oblique direction. It is explanatory drawing of the smoke detection part of the photoelectric smoke detector which concerns on Embodiment 1 of this invention. It is explanatory drawing of the effect | action of the photoelectric smoke detector which concerns on Embodiment 1 of this invention. It is a longitudinal cross-sectional view of the photoelectric smoke detector according to Embodiment 2 of the present invention. FIG. 8 is an exploded perspective view of a smoke guiding portion of the photoelectric smoke detector shown in FIG. 7. FIG. 8 is a perspective view of a flow path upper surface forming member that constitutes a smoke guiding section of the photoelectric smoke detector shown in FIG. 7. FIG. 8 is a perspective view of a flow path lower surface forming member that constitutes a smoke guiding portion of the photoelectric smoke detector shown in FIG. 7.

[Embodiment 1]
The photoelectric smoke detector 1 according to the present embodiment has an outer cover 3 and a back cover 5 that covers an opening on the upper surface of the outer cover 3, and a housing made up of the outer cover 3 and the back cover 5 has a The smoke guiding section 7, the optical stand 9, and the printed board 11 are arranged in this order from the lower side in the attached state (see FIG. 1).
Hereinafter, each configuration will be described in detail.
Note that the photoelectric smoke detector 1 shown in FIG. 1 is oriented in the same direction as when it is mounted on the ceiling surface, and in the present specification, “up” means that the photoelectric smoke sensor 1 is mounted on the ceiling surface. In the above, "upper" side (ceiling surface side) is referred to, and "lower" is "lower" side (lower side of the ceiling surface).

<Outer cover>
As shown in FIGS. 2 to 4, the outer cover 3 includes a flat cylindrical main body 13 having an open upper portion, and a bottomed cylinder having a smaller diameter than the main body 13 protruding downward in the central portion of the main body 13. The protrusion 15 is provided.
The optical stand 9 is housed in the main body 13.
The smoke guiding portion 7 is housed in the projecting portion 15, and a rectangular window portion 17 for inflowing smoke is formed on the peripheral wall of the projecting portion 15.

<Back cover>
As shown in FIGS. 1 and 4, the back cover 5 is made of a disk-shaped plate and covers the upper opening of the outer cover 3.

<Smoke guide>
The smoke guiding portion 7 is provided below the smoke detecting portion 59, and introduces the inflowing smoke into the smoke detecting space 57 (see FIG. 5) formed in the optical stand 9, and as shown in FIG. The flow path upper surface forming member 19 which is arranged on the upper side in the installed state and forms the upper surface of the smoke flow path 61 (see FIG. 1), and the lower surface of the smoke flow path 61 which is arranged so as to cover the flow path upper surface forming member 19 The flow path lower surface forming member 21 is formed.

<Flow path upper surface forming member>
The flow path upper surface forming member 19 is a cylindrical member having an opening at the center, and the outer shape thereof is a cylindrical portion 23 on the upper side and an inverted truncated cone shape portion 25 with the lower side decreasing in diameter. (See Figures 2 and 3).
Inside the flow path upper surface forming member 19, a pedestal 27 is formed at a boundary portion between the cylindrical portion 23 and the truncated cone-shaped portion 25, and the pedestal 27 includes a smoke detector 59 (see FIG. 3). The part housing part 28 is formed (see FIGS. 2 and 4).
In addition, three rod-shaped members 29 are provided upright on the rear side of the flow path upper surface forming member 19 and on the outer peripheral side of the base portion 27 (see FIG. 4). The flow path upper surface forming member 19 is fixed to the optical base 9 by inserting the pillar member 31 into the insertion hole 31a (see FIG. 3).

As shown in FIG. 3, an inner inclined surface portion 33 such as a peripheral surface of a truncated cone whose diameter decreases from the lower end toward the center is formed on the inner side of the truncated cone-shaped portion 25, and the upper end of the inner inclined surface portion 33 is open. Further, the smoke introducing port 35 is provided for introducing smoke into the smoke detecting section 59. In other words, the truncated cone-shaped portion 25 forms an annular mountain-shaped ridge portion with the inner inclined surface portion 33 and the outer inclined surface portion 37 described later, and the central portion of the mountain-shaped ridge portion is the smoke introducing port 35. Has become.
The outer side of the truncated cone-shaped portion 25 is an outside inclined surface portion 37 like a side surface of a truncated cone, and the outside inclined surface portion 37 and the inside inclined surface portion 33 together with the flow passage lower surface forming member 21 include the smoke flow passage 61 (see FIG. 1)).

<Flow path lower surface forming member>
The flow path lower surface forming member 21 has a cylindrical shape, and a plurality of rectangular smoke inflow windows 39 for introducing smoke are formed on the peripheral surface (see FIGS. 2 to 4). A rib 41 slightly protruding outward is formed on the upper edge of the smoke inflow window 39. The rib 41 has a function of preventing smoke from flowing into the main body portion 13 side of the outer cover 3.
Further, two locking pieces 43 are provided on the upper end of the flow path lower surface forming member 21 (see FIG. 2). By locking the locking pieces 43 to the peripheral edge of the optical base 9, the flow path lower surface forming member is formed. 21 is attached to the optical table 9.

An insect screen 45 is installed over the entire circumference of the flow path lower surface forming member 21 where the smoke inflow window 39 is formed.
The inner wall of the bottom surface of the flow path lower surface forming member 21 is a portion that constitutes the lower surface of the smoke flow path 61, and is provided with a first annular raised portion 47 that is provided annularly and is raised upward, and an inner peripheral side of the first raised portion 47. Further, a mountain-shaped second raised portion 49 having a height higher than that of the first raised portion 47 is formed continuously from the lower portion of the first raised portion 47 (see FIGS. 2 and 4).
The height of the top portion 49a of the second raised portion 49 does not extend to the smoke detecting portion and is below the position of the smoke introducing port 35 of the flow path upper surface forming member 19, as shown in FIG. Is set to.
The first raised portion 47 and the second raised portion 49 have a relationship such that the mountain formed of the second raised portion 49 is surrounded by the outer ring mountain formed of the first raised portion 47.

<Optical stand>
As shown in FIG. 5, a light emitting element 51, a light receiving element 55 housed in a shield box 53, and a smoke detection space 57 into which smoke is introduced are formed in the optical table 9 to detect scattered light due to smoke. A smoke detector 59 is provided. An optical trap 60 is formed on the inner peripheral wall of the smoke detector 59.

<Printed circuit board>
The printed circuit board 11 is mounted on the upper surface side of the optical stand 9 and has electrical components mounted thereon. Then, the upper surface side of the printed circuit board 11 is covered with the back cover 5.

A state in which the above-described components are assembled will be described.
The printed board 11 is fixed to the back cover 5 while the printed board 11 is fixed to the optical stand 9.
Further, the flow path upper surface forming member 19 is attached to the optical base 9, and the flow path upper surface forming member 19 is covered so as to cover the whole of the flow path upper surface forming member 19, that is, the flow path upper surface forming member 19 is inserted. Are attached to the optical table 9. In this state, the back cover 5, the printed board 11, the optical stand 9, the flow path upper surface forming member 19 and the flow path lower surface forming member 21 are assembled.
In this state, by attaching the back cover 5 to the outer cover 3, the whole assembly is completed.

In the assembled state, the bottom surface of the flow path lower surface forming member 21 and the outer inclined surface portion 37 and the inner inclined surface portion 33 of the flow path upper surface forming member 19 are arranged to face each other with a predetermined gap therebetween, and this gap becomes the smoke flow passage 61. (See Figure 1).
The smoke flow passage 61 is formed on the inner peripheral side of the first smoke flow passage 63 and the first smoke flow passage 63 that guides the introduced smoke obliquely downward and inward. The second smoke flow path 65 guides the passed smoke obliquely upward toward the smoke detector 59 side.
In the first smoke flow passage 63, the flow passage width (distance between the flow passage lower surface and the flow passage upper surface) in the vertical direction gradually decreases from the outer peripheral side toward the inner peripheral side, and the flow passage width becomes the smallest at the lowermost portion. Is the narrowest part 67.
In the space in which the smoke flow path 61 is formed, the smoke flow path 61 is lowered by the first smoke flow path 63, and then the smoke flow path 61 is moved upward by the second smoke flow path 65. It also has a function as a stray light part that makes it difficult for light to enter due to repeated reflection and attenuation. The smoke flow path 61 is formed of a black member to attenuate outside light.

The operation of the photoelectric smoke detector 1 of the present embodiment configured as described above will be described with reference to FIG.
Smoke or steam existing in the space where the photoelectric smoke detector 1 is installed passes through the insect net 45 and flows into the smoke flow path 61 as shown by the arrow in FIG.
The smoke and steam that flow in have different movements at the time of inflow due to the difference in particle size (smaller smoke particles) and the difference in their components, so smoke and steam will be described separately below.

<Smoke movement>
The smoke flowing into the smoke flow path 61 passes through the first smoke flow path 63 and the second smoke flow path 65, and then flows into the smoke detection space 57 from the smoke introduction port 35.
As described above, the flow width (flow path height) of the first smoke flow path 63 gradually narrows toward the inner circumference, so the flow velocity gradually increases and passes through the narrowest portion 67. The generated smoke is vigorously guided obliquely upward along the second smoke flow path 65 and flows into the smoke detection space 57.

<Movement of steam>
Since the smoke flow path 61 is a relatively narrow space sandwiched by the bottom surface of the flow path lower surface forming member 21 and the outer inclined surface portion 37 and the inner inclined surface portion 33 of the flow path upper surface forming member 19 as described above, The steam flowing in flows while touching the upper surface and the lower surface of the smoke flow path 61. When steam flows through a narrow space, the particles collide with each other and stick to each other to become large particles, and since steam has the property of adhering to the wall surface, the steam adheres to the wall surface of the flow path and is reduced in volume.

  Further, when the steam passes through the narrowest portion 67, the collision rate of the particles increases, and the particle diameter further increases. The particles of steam having a large particle diameter have no ascending force, and escape from the smoke guiding portion 7 facing each other without being introduced into the smoke introducing port 35.

  As described above, since the smoke particles are fine and easily pass through even in a narrow place, the smoke flow path 61 of the present embodiment increases the flow velocity and is introduced into the smoke introduction port 35. Particles are large and easily stick to the wall surface. Therefore, in the flow path of the present embodiment, the smoke introduction port 35 does not adhere to the wall surface in the middle of the flow path, or becomes large particles and loses the rising momentum. Not introduced.

  Further, the smoke flow path 61 is a zigzag flow path in which the first smoke flow path 63 and the second smoke flow path 65 are bent and connected, and since the flow path length is long, In the process of passing through the smoke flow path 61, the steam has a great effect of adhering to the wall surface of the flow path and being reduced in amount.

In addition, in the present embodiment, the height of the top portion 49a of the second raised portion 49 is set to be lower than the position of the smoke introducing port 35 of the flow path upper surface forming member 19, so that the steam is temporarily Even if the vehicle comes near the top of the second raised portion 49, it is not guided by the second raised portion 49 and introduced into the smoke detecting portion 59 from the smoke introducing port 35.
In this sense, there is a certain effect in setting the height of the second raised portion 49 as described above, but in the present invention, the first smoke flow passage 63 and the second smoke flow passage 65 have the above-described shapes. By doing so, steam is normally prevented from reaching the vicinity of the top of the second raised portion 49, and therefore it is not essential to set the height of the second raised portion 49 as described above.

  As described above, in the smoke guiding portion 7 of the present embodiment, the smoke is smoothly guided to the smoke detecting portion 59, and steam is detected by reducing the amount of the steam or raising the rising force in the middle of the smoke flow path 61. Since it does not flow into the smoke portion 59, erroneous detection due to steam is prevented.

  In the present embodiment, an example is shown in which the first smoke flow passage 63 gradually narrows from the outer peripheral side toward the inner peripheral side and becomes the narrowest at the end of the first smoke flow passage 63. The first smoke flow channel 63 does not need to gradually narrow its flow channel width, and if the narrowest channel 67 having the narrowest flow channel width is present at the end of the first smoke flow channel 63, the above-described operation causes false detection. The effect of prevention can be obtained.

  A guide member may be provided on the outer inclined surface portion 37 of the flow path upper surface forming member 19 to guide the smoke flowing into the first smoke flow path 63 inward. An example of a specific shape of the guide member will be described in the second embodiment.

[Second Embodiment]
The photoelectric smoke detector 71 according to the second embodiment will be described with reference to FIGS. 7 to 9. 7 to 9, the same parts as those in the first embodiment are designated by the same reference numerals. Further, the present embodiment is different from the first embodiment only in the shapes of the flow path upper surface forming member 73 and the flow path lower surface forming member 75. Therefore, in the following, the flow path upper surface forming member 73 and the flow path lower surface forming member 73 will be described. The member 75 will be described.

<Flow path upper surface forming member>
The basic shape of the flow path upper surface forming member 73 is the same as that of the first embodiment, but a plurality of slits 77 are provided in the outer inclined surface portion 37 and the inner inclined surface portion 33 of the truncated cone shaped portion 25 at predetermined intervals in the circumferential direction. It is different from the first embodiment in that it is formed and that a guide member 79 for guiding smoke toward the inner inclined surface portion 33 is provided on the outer inclined surface portion 37.

The purpose of forming the slit 77 is to increase the surface area of the smoke flow passage 61 and to attach steam to the inner wall of the smoke flow passage 61.
The slits 77 formed on the outer inclined surface portion 37 and the inner inclined surface portion 33 are formed independently of each other, and the outer inclined surface portion 37 and the inner inclined surface portion 33 are not communicated by the slit 77.

As shown in FIGS. 8 and 9, the guide member 79 is composed of six plate-like members provided so as to project along the outer inclined surface portion 37 and below the outer inclined surface portion 37. .
The plate-shaped bodies are radially arranged so that the direction along the plate surface (that is, the longitudinal direction) is the radial direction. By providing the guide member 79 made of the plate-shaped bodies arranged in this manner, The smoke flowing into the first smoke flow path 63 of the smoke section 7 is guided to the second smoke flow path 65 side without passing through the outside as it is, so that the smoke detection effect is enhanced.
The number of plate-like members forming the guide member 79 is not limited to six, and if there are three or more, the smoke is guided to the second smoke flow path 65 side.

<Flow path lower surface forming member>
Regarding the inner wall of the bottom surface of the flow path lower surface forming member 75, the second raised portion 49 on the inner peripheral side is similar to that of the first embodiment, but the shape of the first raised portion 47 on the outer peripheral side is different. As shown in FIG. 10, the first raised portion 47 is provided with a number of slits 81 on both the ascending slope and the descending slope of the first raised portion 47 at predetermined intervals in the circumferential direction.
As shown in FIG. 10, the slits 81 formed on the ascending slope and the descending slope of the first raised portion 47 are independent of each other, and the slit 81 connects the ascending slope and the downward slope of the first raised portion 47. I haven't.
The reason why the slit 81 is formed in the first raised portion 47 is that the surface area of the smoke flow passage 61 is increased and steam is attached thereto, as in the case of the flow passage upper surface forming member 73 described above.

  The large flow of smoke or steam flowing into the smoke guiding portion 7 of the second embodiment is similar to that of the first embodiment, but the slit 81 is formed in the first smoke flow passage 63 and the second smoke flow passage 65. As a result, smoke and steam also flow in the slit 81 in the first smoke flow path 63 and the second smoke flow path 65, increasing the flow path wall area. Therefore, the steam flowing into the smoke flow path 61 can be efficiently attached to the wall surface of the flow path.

1 Photoelectric smoke detector (Embodiment 1)
3 Outer cover 5 Back cover 7 Smoke guiding part 9 Optical stand 11 Printed circuit board 13 Main body part 15 Projection part 17 Window part 19 Flow path upper surface forming member 21 Flow path lower surface forming member 23 Cylindrical shaped part 25 Frustum shaped part 27 Stand part 28 Smoke detection section accommodation section 29 Rod-shaped member 31 Column member 31a Insertion hole 33 Inner inclined surface section 35 Smoke introduction port 37 Outer inclined surface section 39 Smoke inflow window 41 Rib 43 Locking piece 45 Insect screen 47 First raised section 49 Second raised section 49a Top 51 Light emitting element 53 Shield box 55 Light receiving element 57 Smoke detecting space 59 Smoke detecting section 60 Optical trap 61 Smoke flow path 63 First smoke flow path 65 Second smoke flow path 67 Narrowest part <Second embodiment>
71 Photoelectric smoke detector (Embodiment 2)
73 flow path upper surface forming member 75 flow path lower surface forming member 77 slit (flow path upper surface forming member)
79 guide member 81 slit (flow path lower surface forming member)

Claims (5)

A smoke detecting section for detecting smoke by detecting scattered light due to smoke, and a smoke guiding section provided below the smoke detecting section for attenuating outside light and introducing the inflowing smoke into the smoke detecting section. A photoelectric smoke detector comprising:
The smoke guiding portion has a tubular flow path upper surface forming member having an outer inclined surface portion and an inner inclined surface portion and having an opening in the center, a first raised portion provided in an annular shape and raised upward, and the first raised portion. A smoke channel formed by combining a flow path lower surface forming member having a second raised portion continuously formed from a lower portion of the first raised portion on the inner peripheral side and vertically facing each other ,
A first smoke flow path該煙passage which directed towards the smoke introduced is formed by the outer inclined surface portion and the first raised portion inwardly, the inner the inner peripheral side of the first smoke flow path A photoelectric conversion device having a second smoke flow path, which is formed by an inclined surface portion and the second raised portion, and which guides smoke passing through the first smoke flow path obliquely upward toward the smoke detecting section side. Smoke detectors. A smoke detecting section for detecting smoke by detecting scattered light due to smoke, and a smoke guiding section provided below the smoke detecting section for attenuating outside light and introducing the inflowing smoke into the smoke detecting section. A photoelectric smoke detector comprising:
The smoke guiding portion has a smoke flow path formed by combining vertically facing parts, and the smoke flow path includes a first smoke flow path for guiding the introduced smoke inward and the first smoke flow path. 1 has a second smoke flow path formed on the inner peripheral side of the smoke flow path and guiding smoke passing through the first smoke flow path obliquely upward toward the smoke detecting section side,
In the smoke-guiding portion, a narrowest width portion having a narrow width in the height direction is formed at the boundary between the first smoke flow path and the second smoke flow path. Smoke detectors. The photoelectric smoke detector according to claim 1 or 2, wherein the first smoke flow passage has a flow passage width that gradually narrows inward in a height direction .   The member forming the lower surface of the second smoke flow path is set such that the height of the top of the member does not extend to the smoke detecting section and is below the smoke detecting section. The photoelectric smoke detector according to any one of claims 1 to 3, The photoelectric smoke detector according to any one of claims 1 to 4, wherein a slit that is not in communication with the wall surface of the first smoke flow path and / or the second smoke flow path is formed.

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