JPS62215849A - Fire detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fire detector having a chamber provided with a sensor. The above sensor is a sensor that detects combustion materials, such as an optical smoke sensor.

[Conventional technology]

As is known in the art, an optical sensor comprises a light emitting diode (LED) as a light emitter and a photodiode as a light receiver, which is placed indoors and has access to smoke from the outside air. The optical axes of the emitter and receiver are arranged in the room at an angle to the normal pressure. These optical axes are arranged to meet in the central region of the chamber where smoke first appears for efficient detection. The angle here refers to the angle in the vertical plane when the fire detector is normally installed on the ceiling, and there is no direct optical transmission path between the emitter and the receiver.

The above procedure takes care to prevent the reflection of Bi2O from the light emitter from reaching the light receiver.

[Problems to be solved by the invention] Fire detectors using such optical sensors have many difficult optical problems. Normally, smoke enters the room through screens, but it is impossible to make the dimensions of the screens small enough to prevent the entry of very small insects, which can cause light scattering. This will give off a false alarm. Additionally, conventional rope arrangements do not permit repeated detection because the smoke carried by the gas stream impinges on the detector from various directions in the vertical plane.

These impacts from various directions are usually caused by changes in the velocity of the gas flow.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fire detector with an optical sensor arranged indoors so as to have good detection performance and reduce false alarms caused by objects such as insects. .

Another object of the invention is to provide a particle or gas detector that is superior to the prior art in detecting velocity changes in gaseous media.

Blank below [Means for solving the problem] According to the present invention, there is provided a fire detector disposed on an installation surface such as a ceiling surface, comprising a chamber having a board and opening to the outside air,
The peripheral area of the board lies on a single plane parallel to the top surface of the fire detector when the fire detector is mounted thereon, and inside the peripheral area of the board there are a pair of mutually opposed inclined slopes. recesses are formed, the recesses being formed to meet at a generally central ridge extending laterally on the substrate with respect to a line connecting the recesses, and an end of one recess spaced from the ridge; a light emitter provided at an end of another recess spaced apart from the protuberance and having an optical path along the recess; in which both optical paths are formed at different angles to the single plane, and both emitter and receiver optical rings are formed at a location in the room spaced laterally from the ridge. Provided is a fire detector characterized in that the two sides meet at an angle of 170° to 135°.

Further, according to the present invention, there is provided a particle or gas detector installed on a flat surface such as a ceiling surface, which includes a sensor and which detects particles or gas through one or more openings extending in a plane substantially parallel to the installation surface. With a chamber open to the outside air, a portion of the casing of the fire detector extends outward from the opening, and at least a portion of the gas flow flowing substantially parallel to the plane of the opening is deflected into the plane of the opening. A particle or gas detector configured to pass at right angles is provided.

〔Example〕

The present invention will be described in detail below with reference to the accompanying drawings.

The fire detector includes a kelp-shaped main body 1 to be attached to a ceiling 2, a base plate 3, a casing 4, and a substantially flat annular mesh 5. The casing 4 and the base plate 3 define a chamber 6. The opening area of the net 5 is preferably 1 square 2 or less to prevent insects from flying in and causing a fire alarm. However, the opening size of the mesh cannot be made excessively small. Making the opening size too small will impede the passage of smoke.

The body 1 includes a box 7 with pillars 8 which have jaws 9 that embrace a radial edge 11 of a printed circuit board 12.
．． It has 10. Each jaw 9.10 includes a flexible electric wiper contacting a fixed contact (not shown) on the circuit board 12.
A connector 13 is provided.

The substrate 3 is circular in shape and has an upright wall 15 formed in its flat peripheral area 14 and a shoulder 16 formed inside the upper part of the upright wall 15 . The substrate 3 inside the region 14
An arcuate protuberance 17 is formed on the substrate, which is offset from the center line of the substrate. The upper surface 18 of the ridge 17 lies in a plane containing the upper surface of the region 14 . Also, as shown in FIG. 2, the protuberance 17 is tapered from the nib end 19 to the wide end 20.
A similarly tapered central groove 21 is also formed. The centerline of the central groove 21 is offset relative to the substrate and is inclined from the centerline of the substrate by a small angle, for example about 2 degrees.

Slanted portions 22 and 23 are formed on both sides of the protuberance 17 up to horizontal flat portions 24 and 25. Inclined part 22
A first groove 26 that reaches an end 27 is provided in the horizontal flat portion 24, and a second groove 28 that reaches an end 29 is provided in the inclined portion 23 and the flat portion 25.

As shown in FIG. 2, the groove 26 lies on the centerline 3o, and the groove 28 is inclined at an angle A with respect to this centerline.

Angle A can be between 3° and 12°, and even 3°
Preferably, the angle is between 5° and 5°.

The angle B between the centerline parallel to the bottom surface of groove 26 and the plane containing region 14 is preferably about 20°. The angle C between the center line parallel to the bottom surface of groove 28 and the plane containing region 14 is preferably about 16 degrees. The angle between both center lines is 135° to 170°
and preferably 140" to 150°. Slanted portion 22
, 23, a stepped portion 31 extends upward from the periphery of the area 1.
It has reached the inner periphery of 4.

The printed circuit board 12 carries supports 32,33. The supports 32 and 33 are formed with main parts 36 and 37, respectively, and are provided with substantially cup-shaped recesses 34 and 35,
By engaging the main parts 36 and 37 with the hook parts 38 and 39 of the board 3, the board 3 and the circuit board 12 are integrally locked. Inner edge 1 of circuit board 12
1 has a recess 40 formed therein. Further, on the lower surface of the substrate 3, there is a hanging wall 41 having the same shape and dimensions as the peripheral edge shape of the recess 40.
, 42 and 43 are formed, which serve to seal the circuit board 12 and to house the aforementioned pillar 8 therein.

When substrate 3 and circuit board 12 are locked together, recess 34 aligns with groove 26 and abuts end 27 of groove 26, and recess 35 aligns with groove 28 and! End 29 of I28
comes into contact with. As shown in FIG. 1, the recess 34 has an inner stepped portion 44 formed therein and a photodiode (not shown) located at the bottom of the recess. The optical path of the photodiode is along the centerline of groove 26 through biconvex lens 45.

A light emitting diode 46 is arranged in the recess 35, the optical path of which runs along the center line of the groove 28. The two center lines mentioned above coincide at point D above the ridge 17 and at a lateral position to the ridge 17. Diode 46 is preferably of the gallium aluminum arsenide type, which emits light at a shorter wavelength (880 wavelength) than the normally used 950 wavelength.

The supports 32 , 33 carry a pair of pillars 47 , 48 and 49 , 50 through slots 51 , 52 in the substrate 3, respectively.

A thermistor 53 is provided across each pair of pillars, with a thermistor coupling member 54 extending downwardly toward the circuit board 12 to hold the thermistor thereto. The upper part of the thermistor is located at the same level as the shoulder 16 of the upright wall 15 and contacts the rope 5.

As can be seen in FIG. 2, a plurality of inwardly sloped support members 55 extend radially inwardly from the upright wall 15. A circumferential ridge 56 is formed on the substrate 3 between these support members 55 . (However, the circumferential ridge 56 is not shown in FIG. 1).

Board 5 having recesses 58 aligned with recesses 40 in circuit board 12
7 contacts the circuit board 12 at several locations (not shown) on the periphery of the vertical board. The plate 57 is carried by the board and is locked to the circuit board 12 and the board 3 by a plurality of arms 59 having bent ends 60 that engage the circuit board. Therefore, the board 3, circuit board 12, and board 57 can be combined and handled as a single unit.

The chamber 6 is covered with a cap 61. The cap 61 has a peripheral wall 62 with an outwardly directed ledge 63 by which the circumferential edge of the mesh 5 is received. cap 61
Several rows of circumferential ridges are formed on the lower surface 64 of the light emitting diode 46, which ridges define surfaces 65a, 65b defined by radii centered on the optical center of the light emitting diode 46.
, 65c, 65d.

65c1.65f respectively. The angles of inclination between these surfaces and the lower surface 64 of the cap are different.

In order to accurately position the cap 61,
is supported by a plurality of legs 66 arranged axially symmetrically, and the legs 6
6 includes a reduced diameter portion 67 inserted into a hole (not shown) in the substrate 3.
is formed.

The cover 4 has an upper portion 68 that abuts the upper surface 69 of the cap 61.
, while holding the peripheral wall 62 and extending the circumferential edge of M45 into the ledge 6.
3 and a hanging skirt portion 70 that locks into place. upper part 68
An extending portion 71 extending outward from the hanging skirt portion 70 and a plurality of spaced radial fins 72 are provided on the outer peripheral edge of the
and a rib 73 connecting the upper portion 68 having a circumferential portion 74. Each fin 72 is formed with a lip 75 that locks the outer peripheral edge of the y45 to the shoulder 16.

The cover 4 is secured to the base plate 3 by a series of scissor fits 76 having enlarged heads 77 inserted into the open lower part 8 of the base plate 3. The mesh 5 and the cap 61 are locked to the substrate 3 by the above engagement.

A plurality of locking members 79 are provided on the periphery of the plate 57, and the receiver of the main body 1 is engaged with the member 80 by rolling the member 80.

The recesses 40, 5B in the circuit board 12 and the plate 57 accommodate the pillars 8 and lock or release the plate 57 relative to the body 1 by mutually rotating the body 1 and other parts of the detector. At the same time, the connector 13 can be engaged or disengaged.

Circuit board 12 and box 7 contain the necessary electrical connectors and circuit elements, and box 7 contains terminals (not shown) accessible through body l. If necessary, the circuit board 12 and box 7 may be modified in accordance with applicant's co-pending application US Pat. No. 8,431,888.
The microcomputer and other circuit elements disclosed in No. 3 can be included.

As is well known, the scattering of the emitted light from the diode 6 by smoke particles in the chamber 6, in particular smoke particles at the slope of point D, is detected by a photodiode in the recess 34.

Using the diode 46 made of gallium aluminum arsenide, which has a wavelength shorter than the normal wavelength,
The relationship between scattering and wavelength is 1nverse fourth
This is important because it depends on power Iai+. Recess 34
Preferably, the diodes in the chamber 6 are associated with a filter that passes the infrared band to eliminate ambient light levels entering the chamber 6. The light does not directly enter the room as it would directly into the diode, but instead enters at a low level due to many reflections.

An important feature of the present invention is that the scattering and reflection of light from diode 46 within chamber 6 in smokeless conditions is reduced to a predetermined constant level.

A predetermined constant level allows for intermittent or continuous monitoring of sensor operation.

Therefore, the inner surface of the chamber 6 is finished with a black texture to reduce false reflections. The pseudo reflected light is reflected from the stepped portion 31, the inner stepped portion 44, the circumferential ridge 56, and the surfaces 65a to 65f.
This can be further reduced by providing .

After much experimentation, it has been determined that a desirable low scattering angle is 10° (if the ideal optical path meets at 170°). In fact, it has been found that the scattering angle of 45° or less is considerably superior to the conventional structure. The various angles between these optical paths, the plane of the area 14 of the substrate 3, the offset position of the chordal ridge 17 and the angle A provide a low scattering angle and allow the photodiode to directly receive the light from the light emitting diode 46. can be prevented from happening. Fragmentation caused by small insects perched in the center of the upper surface 18 is caused by groove 2.
Decremented by 1. If the grooves 21 were not provided, insects in the center of the top surface 18 would cause greater scattering than insects in the edges of the top surface.

Thermistor 53 improves the overall sensitivity of the fire detector and also increases the range of fire types that can be detected.

The mesh 5 also serves as a heat collector for the thermistors connected in parallel. Since these thermistors are non-linear devices, thermistors under high temperature conditions are dominant. The fin 72 has a rib 73 and a vertical skirt portion 7.
The annular space 81 does not extend across the annular gap between 0 and
is exposed to the net 5. Therefore, the hot air can move through the annular space 81 and spread over a wide area.
come into direct contact with.

When the fire detector is installed on the ceiling surface 2 as shown in FIG. 3, smoke carried by the low-velocity air current flows upward through y45 by convection. If the air velocity is high (0.1m/
s or more), most of the airflow flows along the ceiling surface. In such a case, the airflow is redirected by the extensions 71 and the depending skirts 70 (FIG. 1) and passes through the screen 5 at right angles. The fins 72 and lip 73 assist in the above change of direction. According to the invention, even in the case of low velocity airflows, the thickening of the smoke in the air 6 is higher than the thickening in the airflow outside the chamber.

Although the net 5 is provided in the above-described embodiment, the net 5 can be omitted if the area is not affected by insects or if other means for identifying false determinations caused by insects is provided.

Also, although described with reference to an optical smoke sensor, the present invention can be used with any type of particle or gas detector.

[Brief explanation of drawings]

Fig. 1 is an enlarged sectional view of an optical detector according to the present invention, Fig. 2 is a plan view showing the board of the fire detector shown in Fig. 2, and Fig. 3 is a side view of the fire detector attached to the ceiling. . 3... Board, 4... Casing, 5...
... Net, 6 ... Chamber, 14 ... Peripheral area, 17 ... Ridge, 21 ... Longitudinal groove, 3
4, 35... recess, 46... light emitter, 53
...Thermal sensor, 72...Fin, 75
...Rib, 81...Annular space.

Claims (1)

[Claims] 1. A fire detector disposed on an installation surface such as a ceiling surface, comprising a chamber (6) having a substrate (3) and opening to the outside air,
The peripheral area (14) of said substrate (3) lies in a single plane parallel to the top surface of the fire detector when the fire detector is placed thereon; A pair of sloping recesses (34, 35) facing each other are located inside
are formed, and both the recesses (34, 35) have a substantially central bulge (17) extending laterally on the substrate with respect to a line connecting the two recesses.
a light emitter (46) formed to meet at the end of a recess (35) spaced from said ridge (17) and having an optical path along said recess (35);
and an optical receiver provided at the end of another recess (34) spaced from said protuberance (17) and having an optical path along said recess (34), chambers (6) having channels formed at different angles to said single plane and spaced laterally from said ridge (17);
1. A fire detector characterized in that the optical axes of the light emitter (46) and the light receiver meet at a position (D) within the range at an angle of 170° to 135°. 2. The fire detector according to claim 1, wherein both optical axes meet at an angle of 150° to 140°. 3. The fire detector according to claim 1 or 2, wherein both optical paths are arranged at an angle of 3° to 12° in a plane perpendicular to the plane containing the peripheral area (14). . 4. Claim 3 in which the above angle is 3° to 5°
Fire detector as described in section. 5. Any one of claims 1 to 4, wherein the ridge (17) is laterally spaced from the center of the chamber (6).
Fire detectors as described in Section. 6. The fire detector according to claim 5, wherein a longitudinal groove (21) is formed in the ridge (17). 7. The chamber (6) is open to the outside air only through a screen (5) having a small mesh that prevents insects from entering;
The net (5) is approximately flat and extends approximately parallel to the installation surface, and a portion of the casing (4) of the fire detector is covered with the net (5).
5) so that at least a portion of the gas flow entrained with smoke and moving substantially parallel to the plane of the screen (5) is diverted through the screen in a direction perpendicular to the plane of the screen (5). A fire detector according to any one of claims 1 to 6, formed as follows. 8. Fire detector according to claim 7, comprising at least one thermal sensor in contact with the screen (5). 9. The interior of the chamber (6) is provided with a surface finish such that in smoke-free conditions the reflection and scattering of light from the emitter is reduced to a predetermined constant level, which can be monitored weekly or continuously by a sensor. Claim 1 having a shape of
A fire detector described in any one of paragraphs 8 through 8. 10. A particle or gas detector installed on a flat surface such as a ceiling, containing a sensor and opening to the outside air through one or more openings extending in a plane substantially parallel to the installation surface. in which a portion of the fire detector casing (4) extends outward from the opening and at least a portion of the gas flow flowing substantially parallel to the plane of the opening is deflected at right angles to the plane of the opening. A particle or gas detector configured to pass through. 11. An annular space (8) communicating with the opening in the casing (4)
11. The detector according to claim 10, wherein: 1) is formed so that high-temperature air circulates around the annular space and passes through the opening over a wide area. 12. An annular space (8) communicating with the outside of the casing (4)
12. Detector according to claim 11, characterized in that 1) is provided with a series of fins (72) and ribs (75) to direct hot air in different directions. 13. Claim 10 in which the opening is covered with a net (5)
Detector according to any one of paragraphs 1 to 12. 14. Detector according to claim 13, comprising at least one thermal sensor (53) in contact with the mesh (5). 15. A detector consisting of a fire detector and a cooperative smoke sensor.