JP2010040009A - Smoke sensor - Google Patents

Abstract

There is provided a smoke detector in which light reflected by a light shielding body provided in a smoke detection chamber does not become stray light.
A light-shielding body 41 that limits a light projection range (a region surrounded by solid lines A1 and A1) is formed in the smoke sensing chamber 5, and the light-shielding body 41 is connected to the light projecting unit 10. The light-shielding surface 41a that receives direct light is disposed, and the light-shielding surface 41a is disposed at an obtuse angle with respect to the light projecting axis L2.
[Selection] Figure 1

Description

  The present invention irradiates the smoke that has entered the smoke sensing region through the smoke inflow path formed by the gap between the labyrinth walls in the smoke sensing chamber from the light projecting unit, and the light scattered by the smoke is received by the light receiving unit. The present invention relates to a smoke detector that detects light by receiving light at the sensor.

  FIG. 5 is a schematic plan view of a smoke detection chamber of a conventional smoke detector.

  In this smoke detector, a plurality of labyrinth walls 103 are provided in the smoke detection chamber 100, and the light projecting unit 101 is received in a room and the light emitted from the light projecting unit 101 is not received directly. Part 102 is provided, and a smoke sensitive area C is formed by the light projecting range and the light receiving range thereof. In this case, scattered light due to smoke flowing into the smoke sensing area C through the smoke inflow path 104 formed by the gap between the labyrinth walls 103 is received by the light receiving unit 102, and this is used as a light reception signal to exceed the threshold value. The fire alarm signal is output when a fire alarm is issued.

  The light projection range is formed in a region that extends at an angle corresponding to the opening of the light projection window 101a on the both sides of the light projection axis L of the light projecting unit 101, but in such a constant light projection range, Depending on the size of the interior of the smoke sensing chamber 100 and the positional relationship between the light projecting unit 101 and the light receiving unit 102, there are cases where it is inappropriate. That is, when the light projecting unit 101 and the light receiving unit 102 are arranged as shown in FIG. 5, the light receiving unit 102 may receive direct light from the light projecting unit 101 in the light projecting range corresponding to the light projecting window 101 a. There is.

  Therefore, conventionally, as shown in FIG. 5, a light blocking body 105 is provided in which a part of direct light is blocked to narrow a light projection range. In FIG. 5, the area surrounded by the solid lines A and A is shown as a narrowed light projection range. Patent Document 1 discloses a smoke detector having a light shielding wall for the same purpose as described above.

According to the light shielding body 105, a part of the direct light from the light projecting unit 101 is blocked, and the light hitting the light shielding surface 105a is further reflected to various parts in the room, and as a result, the reflected light R is reflected. The light intensity can be weakened to such an extent that the light reception by the light receiving unit 102 is not affected. 5 is formed such that the light shielding surface 105a has an acute angle θ with respect to the light projection axis L. The light shielding member 105 shown in FIG.
JP 2002-352347 A

  By the way, in recent years, the applicant has attempted to accommodate the entire smoke detection chamber in the body and to make the outer shape of the smoke detector into a clean and compact shape with few irregularities. In such cases, it is necessary to make the smoke detection chamber small, but if the smoke detection chamber is made small, the distance between various parts in the room will be shortened, so light that is unnecessary for smoke detection will be Even if the light is reflected at various locations in the room, the light intensity is not sufficiently attenuated, and such reflected light becomes stray light, so that the light receiving unit may not be able to detect normal smoke scattered light.

  Moreover, even if a light-shielding body is installed in such a small smoke sensing room so that the light reflected by the light-shielding surface is further reflected in the room, the light intensity is low because of its small size. There is a possibility that the light is not sufficiently attenuated, and there is a possibility of generating stray light that detracts from the light receiving sensitivity at the light receiving unit.

  The present invention has been proposed in view of such circumstances, and an object of the present invention is to provide a smoke detector that prevents light reflected by a light shield provided in the smoke detection chamber from becoming stray light. .

  In order to achieve the above object, the smoke detector according to claim 1 irradiates light within a smoke detection chamber having a plurality of labyrinth walls around a light projection range extending at a predetermined angle around a light projection axis. A light emitting portion is provided, a light receiving portion is provided at a position where light emitted from the light projecting portion is not directly received, a smoke sensitive area is formed, and the smoke sensitive passage is formed from the smoke inflow path formed by the gap between the labyrinth walls. A smoke detector in which scattered light from smoke flowing into a region is received by the light receiving unit to detect a fire has the following structural features.

  That is, a light-blocking body that restricts the light projection range is formed in the smoke sensing chamber, and the light-blocking body has a light-blocking surface that receives direct light from the light-projecting unit, and the light-blocking surface serves as a light projection axis. It is arranged so as to form an obtuse angle.

  In the smoke detector according to the second aspect, the light shielding surface extends to the outside of the light projection range.

  In the smoke detector according to the third aspect, the light shielding body is provided with a partition wall extending to the outer periphery of the smoke sensing chamber and configured to partition the light projecting portion and the light receiving portion.

  According to the smoke detector according to claim 1, since the light shielding surface of the light shielding body that receives the direct light from the light projecting unit forms an obtuse angle with respect to the light projecting axis, the light reflected by the light shielding surface is directed outward. It is possible to prevent the reflected light from remaining in the room and becoming stray light. In particular, the present invention is suitable for a smoke detector having a small smoke detection chamber in which the light intensity is difficult to be attenuated only by indoor reflection.

  According to the smoke detector of the second aspect, since the light shielding surface extends to the outside of the light projection range, direct light can be shielded without any leakage, and then the reflected surface is reflected and returned thereafter. Light can be further reflected to attenuate the light intensity.

  According to the smoke detector according to claim 3, since the partition wall that extends to the outer peripheral portion of the smoke detection chamber and that partitions the light projecting portion space and the light receiving portion space is continuously provided, the light reflected by the light shielding surface The light intensity can be attenuated while reflecting the light in the light projecting part space, and the light can be taken out of the room. Therefore, the possibility that stray light is generated is further reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 2 is a schematic explanatory view of a smoke detector as an example of the present embodiment, in which (a) is a schematic plan view and (b) is a schematic partial longitudinal sectional view. In FIG. 2, the drawing is performed with the top and bottom reversed from the state of being installed on the ceiling surface. Hereinafter, the vertical relationship of the smoke detector will be described based on this standard.

  The smoke detector 1 is attached to a ceiling or the like. The smoke detector 4 is formed by covering a smoke detection chamber 5 with an insect net 6 having a large number of ventilation holes, a light projecting element 11, a light receiving element 21, and other electronic devices. The circuit board 3 on which components (not shown) are mounted, and a disk-shaped body 2 that accommodates the above-described members and other members and is attached to the ceiling surface. The smoke sensing chamber 4, the insect net 5, the light projecting element 11, and the light receiving element 21 are shown in FIG.

  The body 2 includes a base 2a and a cover 2b. A large number of openings 2c are formed in the outer periphery of the cover 2b by vertical and horizontal bars 2ba. In the body 2, the smoke detector 4 is assembled and accommodated and fixed to the circuit board 3. In this embodiment, the entire smoke detector 4 is accommodated in the body 2 and has a clean shape with less unevenness as a whole. Accordingly, the smoke detector 4 is also small in size. Contained.

  FIG. 1 is a schematic plan view showing the internal structure of the smoke detection chamber 5 of the smoke detector 1. In FIG. 1, the insect net 6 is simply illustrated by broken lines, and the circuit board 3 is not shown.

  The light projecting element 11 and the light receiving element 21 on the circuit board 3 are respectively the light projecting cover 12 and the light receiving cover 22 provided in the smoke sensing chamber 5 in a state where the circuit board 3 and the smoke sensing body 4 are integrated. Is housed in.

  As shown in FIGS. 1 and 2, the smoke detector 4 has a substantially circular shape, and the rear portions of the light projecting cover 12 and the light receiving cover 22 formed in the smoke sensing chamber 5 slightly protrude. Note that the rear portions of the light projecting cover 12 and the light receiving cover 22 are projected in order to make the smoke sensing chamber 5 wider. Further, the inside of the smoke sensing chamber 5 has a structure for optically detecting smoke appropriately by the light projecting element 11 and the light receiving element 21.

  The smoke sensing chamber 5 includes a light projecting unit 10, a light receiving unit 20, a plurality of labyrinth walls 30, a light shielding body 41, and the like. The light projecting unit 10 is disposed on the outer peripheral portion, and the light receiving unit 20 is provided at an outer peripheral position where the light from the light projecting unit 10 is not directly received. Note that the smoke detection chamber 5 may be formed by forming a peripheral wall in which a part below the labyrinth wall 30 and the light shielding body 41 is hidden on the outer peripheral portion thereof.

  The light projecting unit 10 includes the light projecting element 11 accommodated in the light projecting cover 12, and the light receiving unit 20 includes the light receiving element 21 accommodated in the light receiving cover 22. The light projecting cover 12 and the light receiving cover 22 are integrally formed on the optical base 7 together with the labyrinth wall 30, the light shielding body 41, and the like. The light projecting element 11 is made of a light emitting diode or the like, and the light receiving element 21 is made of a photodiode or the like.

  The light projecting cover 12 has a light projecting window 12 a that opens toward the inside of the smoke sensing chamber 5, while the light receiving cover 22 is a light receiving window 22 a that opens toward the inside of the smoke sensing chamber 5. have. The optical axis L2 of the light exiting from the projection window 12a and the optical axis of the light entering the light receiving window 22a are both substantially parallel to the inner bottom surface 7a of the optical base 7.

  The light projecting unit 10 projects the light from the light projecting element 11 accommodated in the light projecting cover 12 so as to reach the labyrinth wall 31 on the opposite side through the light projecting window 12a and the approximate center of the smoke sensing chamber 5. It is configured to irradiate light to a light projection range (region surrounded by solid lines A and A) determined by the light window 12a and the light shield 41. On the other hand, the light receiving unit 20 is configured to receive light from a light receiving range (a region surrounded by solid lines B and B) defined by the light receiving window 22a and the light blocking body 41.

  The light projecting area and the light receiving area overlap at the approximate center of the smoke sensing chamber 5, and a smoke sensitive area C is formed there. That is, in the smoke sensing chamber 5, when the light flowing into the smoke sensing area C is irradiated with light from the light projecting unit 10, the light receiving unit 20 receives the scattered light of the smoke that has received the light, The light reception signal is transmitted to a circuit unit (not shown) to determine fire.

  In addition, although the thing of this embodiment has the characteristics in the light-shielding body 41, this is explained in full detail after demonstrating the other structure of the smoke detection chamber 5. FIG.

  The plurality of labyrinth walls 30 are formed in a substantially flat plate shape, are erected from the inner bottom surface 7a of the optical base 7 to the upper end of the smoke sensing chamber 5, and are arranged on the outer peripheral side (hereinafter referred to as outer ends, The opposite end is referred to as the inner end.) The smoke inlet 5a is formed by the gap between the two labyrinth walls 30, and the inner side of the smoke flow is smoked by the gap sandwiched between the two labyrinth walls 30. An inflow path 5b is formed. The plurality of smoke inflow passages 5b formed by the plurality of labyrinth walls 30 have an effect of inducing smoke to the smoke sensing region C located substantially in the center of the room.

  Further, the labyrinth wall 30 has a smoke inducing action, and external light does not enter through the smoke inlet 5a and the smoke inflow path 5b so that the smoke sensing function is not unstable due to light from the outside. It also has an external light blocking action. In particular, the light emitting side and light receiving side labyrinth walls 31 and 32 have their inner ends 31a and 32a not directed toward the center of the room but directed clockwise or counterclockwise so that smoke can flow in and the smoke inlet 5a. It arrange | positions so that the light which entered from may be interrupted | blocked by the outward wall surfaces 31d and 32d of the labyrinth walls 31 and 32. FIG.

  Note that the labyrinth wall is preferably a flat plate as in the present embodiment when the smoke sensing chamber 5 is small, and is arranged in combination of a clockwise direction and a counterclockwise direction. You may arrange and arrange the well-known thing of "<" shape.

  In the present embodiment, as shown in FIG. 1, when the room is divided by a center line L1 connecting the center and the center of the short arc SS formed by the light projecting unit 10 and the light receiving unit 20, the light receiving unit 20 is The semicircle area | region arrange | positioned and the semicircle area | region where the light projection part 10 is arrange | positioned are formed. In the semicircular region where the light receiving unit 20 is disposed, a light emitting side labyrinth wall 31 that receives direct light from the light projecting unit 10 is disposed, while on the other hand, the semicircular region where the light projecting unit 10 is disposed A light-receiving side labyrinth wall 32 that blocks direct external light from entering the light-receiving unit 20 is provided. Reference symbol SL indicates a long arc formed by the light projecting unit 10 and the light receiving unit 20.

  The light emitting side labyrinth wall 31 and the light receiving side labyrinth wall 32 face each other at the inner ends 31a, 32a, that is, the inner end 31a of the light emitting side labyrinth wall 31 faces in a counterclockwise (counterclockwise) direction. The inner end 32a of the light receiving side labyrinth wall 32 faces in a clockwise (clockwise) direction. That is, in the illustrated example, all the inward wall surfaces 31 c of the three light emitting side labyrinth walls 31 face the direction of the light receiving unit 20, and all the inward wall surfaces 32 c of the light receiving side labyrinth wall 32 face the direction of the light projecting unit 10.

  According to such a structure, in the light emitting side labyrinth wall 31, the inward wall surface 31 c receives direct light reaching the smoke sensing region C from the light projecting unit 10, but the light is outside the light receiving unit 20. Reflected in the direction and hitting the outward wall surface 31d of the adjacent labyrinth wall 31, the smoke inflow path 5b tries to go outside so as to reverse the smoke. Therefore, when the direct light from the light projecting part 10 passes through the smoke sensing region C, it is not reflected toward the light receiving range even by reflection on the light projecting side labyrinth wall 31, and the light intensity is attenuated and emitted to the outside. Is done.

  Further, since the inward wall surface 32c of the light receiving side labyrinth wall 32 faces the light projecting unit 10, if the light is irradiated from the light receiving unit 10 toward the light receiving side labyrinth wall 32, it is the same as the light projecting side labyrinth wall 10. In addition, the light tries to go outside while being reflected by the adjacent labyrinth wall 32. That is, by arranging the light receiving side labyrinth wall 32 in this way, it is possible to avoid receiving light from the outside directly by the light receiving unit 20.

  Further, even when light scattered by the inner end 31a of the light emitting side labyrinth wall 31 is irradiated on the light receiving side labyrinth wall 32, the inward wall surface 32c of the light receiving side labyrinth wall 32 faces the light projecting unit 10. The reflected light goes out of the room.

  As described above, by arranging the light emitting side and light receiving side labyrinth walls 31 and 32 as described above, light emitted from the light projecting unit 10 and unnecessary light or light from the outside can be received in the room. It can prevent that it becomes the stray light which goes to the part 20 and the light reception range. In addition, with such a configuration, it is possible to appropriately flow in smoke and perform appropriate light blocking, thereby configuring the smoke sensing chamber 5 with less stray light.

  Next, the structural features of the light shield 41 in the present embodiment will be described.

  The light blocking body 41 is erected independently between the light projecting window 12 a of the light projecting unit 10 and the light receiving window 22 a of the light receiving unit 20. As described above, the light shielding body 41 mainly limits the light projecting range and the light receiving range.

  According to the width of the opening of the light projection window 12a formed in the light projecting unit 10, the light projection range is in a region surrounded by the solid lines A1 and A1 so as to expand at a predetermined angle around the light projection axis L2. However, since the light blocking body 41 is erected so as to directly block light, the light projection range is narrowed to a region surrounded by the solid lines A1 and A2. On the other hand, with respect to the light receiving range, the light receiving range (region surrounded by the solid lines B and B) is narrowed by the light shield 41.

  As described above, a smoke sensing area C as shown in FIG. 1 is formed in the smoke sensing chamber 5 by the narrowed light projecting range and the narrowed light receiving range.

  The light-shielding body 41 has an effect of forming such a narrow smoke sensing region C, and further reflects the direct light from the light projecting unit 10 or the light reflected and returned indoors to increase the light intensity. It also has an attenuating action, and various reflecting surfaces are formed for this purpose.

  In particular, the light shielding surface 41a facing the light projecting window 12a of the light projecting unit 10 is a surface that reflects the direct light from the light projecting unit 10, and as shown in FIG. It is slightly open outward. In other words, when the light shielding surface 41a forms an obtuse angle with respect to the light projecting axis L2 of the light projecting unit 10, and the light directly strikes the light shielding surface 41a, the light shielding body 40 is erected so as to go to the area of the short arc SS. Has been. In FIG. 1, the locus of light hitting the light shielding surface 41a is indicated by R1.

  The angle θ of the light shielding surface 41a with respect to the light projecting axis L2 is located on the side of the side wall 12b of the light projecting cover 12 of the light projecting unit 10 and the area of the short arc SS, as shown in the example of FIG. It is desirable that the angle be directed toward the smoke inflow passage 5c formed between the labyrinth wall 33 and the labyrinth wall 33.

  In this way, by collecting the reflected light in the area of the short arc SS sandwiched between the light projecting unit 10 and the light receiving unit 20, it is possible to reflect the light in the narrow space and attenuate the light intensity. . Therefore, the stray light caused by the light reflected by the light shield 41 can be reduced. Particularly in the case where the smoke sensing chamber 5 is made small as in this embodiment, even if light is reflected by the flat labyrinth wall 30 in the region on the long arc SL side, the attenuation of light intensity cannot be expected so much. Light reflection on the surface 41a can greatly contribute to prevention of stray light.

  If the reflected light is collected on the parallel path 5c between the light projecting unit 10 and the adjacent labyrinth wall 33, the light is repeatedly reflected between the parallel paths 5c, and finally the outdoor. Even if it goes out or stays indoors, it becomes extremely weak light. FIG. 1 shows the trajectory of the light exiting outside and the light returning upon hitting the insect net 6 or the above-mentioned peripheral wall.

  Further, in the example of FIG. 1, the locus of the light reflected by the light shielding surface 41 a hits the inner end 33 a of the adjacent labyrinth wall 33 and further returns to the other reflecting surface 41 b of the light shielding body 41 is illustrated. In the illustrated example, the returned reflected light is directed toward the front surface of the light receiving unit 20, but this light is also reflected on various parts, so that there is almost no problem with normal light reception by the light receiving unit 20. The light intensity is weakening. In addition, it is desirable to make this reflective surface 41b into the angle which discharge | releases reflected light outside, considering the balance with smoke inflow.

  The light shielding surface 41a also has an auxiliary surface 41aa extending to the outside of the light projection range determined by the light projection window 12a. For this reason, the direct light can be blocked without any mistake, and the auxiliary surface 41aa can further reflect the light reflected and returned thereafter to attenuate the light intensity.

  As the light shielding body 41, the one shown in FIG. 3 may be applied instead of the one shown in FIG.

  The light shielding body 41 shown in FIG. 3 is formed at the tip of a smoke guiding wall 42 extending in the indoor direction from the outer periphery of the smoke sensing chamber 5. The smoke guide wall 42 is formed as a partition wall 42 that divides the region of the short arc SS formed between the light projecting unit 10 and the light receiving unit 20 substantially in the middle. The light shielding surface 41a of the light shielding body 41 forms an obtuse angle θ with respect to the light projecting axis L2 of the light projecting unit 10 as in FIG.

  As described above, since the light shielding body 41 and the partition wall 42 are connected to each other to form the light shielding wall 40, the light projection range can be limited and the reflected light can be confined in a very narrow space. The light intensity can be made extremely weak.

  As shown in FIG. 3, the partition wall 42 is preferably one in which the light shielding body 41 and the outer peripheral portion are continuously connected without a gap, but has little influence on light reception and smoke induction in the vertical and horizontal directions. The space may be open to the extent. That is, a non-continuous wall, a gap between upper and lower portions, a wall connected to the light shielding body 41 and a wall connected to the outer peripheral portion, or a substantially parallel double wall configuration may be used. In other words, any wall may be used as long as the light receiving ability and the smoke guiding ability can be sufficiently exhibited and the light reflected by the light shielding body 41 can be effectively confined in a predetermined space. Further, the position of the partition wall does not have to divide the short arc SS region in half. For example, the other labyrinth walls 30 and 33 in the area of the short arc SS may be used as a partition wall and connected to the light blocking body 41.

  The other structures in FIG. 3 are the same as those in FIG. 1, so the same reference numerals as those in FIG.

  In the above embodiment, as shown in FIG. 2, the smoke detection chamber 5 is provided in the body 2 and the smoke detector 1 is not rough as a whole. However, in the present invention, the smoke detection chamber 5 is provided in the body. The present invention can also be applied to a smoke detector arranged so as to protrude above 2 (below when the smoke detector is attached to the ceiling).

  4A and 4B are explanatory views of a smoke detector in which the upper part of the body protrudes and a smoke detection chamber is provided in the protruding part. FIG. 4A is a schematic plan view, and FIG. 4B is a schematic partial longitudinal sectional view. It is.

  In the smoke detector 1A, a smoke detector 4 including a smoke detection chamber 5 and an insect net 6 is projected at the center of a disc-shaped body 2, and the smoke detector 4 is protected by covering with a protector 8. . A large number of openings 8 b are formed by vertical and horizontal bars 8 a in the outer peripheral portion of the protector 8 in order to allow smoke to flow into the smoke sensing chamber 5. In the figure, reference numeral 3 denotes a circuit board provided with a light projecting element and a light receiving element (not shown).

  Although the structure in FIG. 1 or FIG. 3 is applied to the structure inside the smoke sensing chamber in this embodiment, in particular, the structure of the light shielding body 41, the operation and effect are the same, and the description thereof is omitted.

  In the above embodiment, the smoke detector in which the light projecting unit, the light receiving unit, and the smoke sensing area are arranged in a plane is shown. Alternatively, the present invention can be applied to a device disposed below, that is, a device in which the optical axes of the light projecting unit and the light receiving unit are inclined upward or downward.

It is a schematic plan view which shows the internal structure of the smoke detection chamber used for the smoke detector which is one Embodiment of this invention. It is a schematic explanatory drawing of the smoke detector, (a) is a schematic plan view, (b) is a schematic partial longitudinal cross-sectional view. It is a schematic plan view which shows the internal structure of the other smoke detection chamber used for the smoke detector which is one Embodiment of this invention. It is explanatory drawing of the smoke detector which is other embodiment of this invention, (a) is a schematic plan view, (b) is a schematic partial longitudinal cross-sectional view. It is a schematic plan view of the smoke detection chamber of the conventional smoke detector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Smoke detector 2 Body 3 Circuit board 4 Smoke detector 5 Smoke detection chamber 5a Smoke inlet 5b Smoke inflow path 10 Light projecting part 11 Light projecting element 12 Light projecting cover 12a Light projecting window 12b Side wall 20 Light receiving part 21 Light receiving element 22 Light receiving cover 22a Light receiving window 30 Labyrinth wall 31 Light emitting side labyrinth wall 32 Light receiving side labyrinth wall 33 Labyrinth wall adjacent to the light projecting part 41 Light shielding body 41a Light shielding surface 41aa Auxiliary surface 40 Light shielding wall 42 Partition wall A Solid line B B Solid line showing both sides of the light receiving range C Smoke sensitive area

Claims (3)

A smoke sensing chamber with multiple labyrinth walls is provided with a light projecting section that irradiates light in a light projecting range that extends at a predetermined angle around the light projecting axis, and directly receives the light emitted from the light projecting section. A smoke sensing area is formed by providing a light receiving part at a position where no smoke is received, and the light scattered by the smoke flowing into the smoke sensing area from the smoke inflow path formed by the gap between the labyrinth walls is received by the light receiving part to cause a fire. In a smoke detector that detects
In the smoke sensing chamber, a light-shielding body that limits the light projection range is formed,
The light-shielding body has a light-shielding surface that receives direct light from the light-projecting section, and the light-shielding surface is disposed so as to form an obtuse angle with respect to the light-projecting axis. . In claim 1,
The smoke detector, wherein the light shielding surface extends to the outside of the light projection range. In claim 1 or 2,
A smoke detector, wherein a partition wall extending to the outer periphery of the smoke sensing chamber and continuously separating the light projecting unit and the light receiving unit is provided on the light shielding body.

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