JP2010237738A - Smoke sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secure smoke sensor which is free from leak of laser light out of a dark box. <P>SOLUTION: The smoke sensor includes: an optical case 2 the inside of which is the dark box; a light receiving element 12 which receives scattered light by smoke particles present in a smoke detection part 25 of the light emitted from a laser light source 11 disposed within the optical case; a light receiving amplifier circuit 41 which amplifies the output signal of the light receiving element; and a fire determination part 15 which determines a fire when a detection level obtained by A/D converting the amplified output signal is a threshold or more. The optical case 2 is composed of an optical cover 30 and a box body 21, and includes an opening detection part 33 which detects opening of the cover 30, and a control part 42 which extinguishes the laser light source or set the light emitting cycle of the laser light source longer than when the cover is closed, according to the output signal of the opening detection part. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a smoke detector for detecting a fire.

  A sampling tube type smoke detector is used as a conventional smoke detector. The smoke detector is configured to introduce a closed casing (dark box), a light emitting element and a light receiving element disposed in the dark box, and sampling air of a monitoring area into the dark box, and a smoke detecting unit of the dark box Supply / exhaust means for passing the exhaust gas through the exhaust gas. In the smoke detector, the irradiation light emitted from the light emitting element is scattered by smoke particles present in the smoke detecting section, and the light receiving element receives the scattered light to perform fire discrimination. During the fire monitoring, most of the light emitted from the light emitting element is attenuated by the light trap, but a part of the light is present as diffracted light in the smoke detector.

Japanese Patent No. 3714926

  In some cases, the smoke detector may be exposed to the interior by removing the cover of the housing for repair and inspection. In this case, if the cover is removed while the light emitting element is emitting light, the irradiation will be performed. Since light (laser light) may enter the eyes of workers, the danger is high.

  In view of the above circumstances, an object of the present invention is to provide a safe smoke detector in which laser light does not leak out of a dark box.

  The present invention relates to an optical case having a dark box inside, a laser light source disposed in the optical case, and a light receiving element that receives light scattered by smoke particles that are emitted from the laser light source. A smoke detector comprising: a light receiving amplification circuit that amplifies an output signal of the light receiving element; and a fire determination unit that performs a fire determination when a detection level obtained by A / D converting the amplified output signal is equal to or higher than a threshold value. The optical case includes an optical cover and a box, and an open detection unit that detects opening of the optical cover, and an output signal of the open detection unit turns off the laser light source or a light emission period of the laser light source And a control unit for making the length longer than that at the time of closing the lid.

  The present invention relates to an optical case having a dark box inside, a laser light source disposed in the optical case, and fire detection in which light emitted from the laser light source receives scattered light by smoke particles present in the smoke detecting section. Smoke sensing comprising: a light receiving element for light reception; a light receiving amplification circuit for amplifying an output signal of the light receiving element; and a fire determination unit for detecting a fire when the detection level obtained by A / D converting the amplified output signal is equal to or greater than a threshold value The optical case is composed of an optical cover and a box, and an output of the open detection unit for detecting the opening of the optical cover, and the output of the fire detecting light receiving element due to an increase in diffracted light when the cover is closed is greater than or equal to a threshold value. When it is determined that there is an abnormality, the laser light source is turned off or the light emission period of the laser light source is made longer than normal when the open signal of the open detection unit or the output of the light receiving element for fire detection is abnormal. Control unit , Characterized in that the provided.

  In the opening detection unit according to the present invention, when the short-circuit pin provided on the optical cover and the short-circuit connector provided on the box are turned off, the control unit turns off the laser light source or the laser light source. The light emission period is made longer.

The open detection unit of the present invention includes an external light detection light receiving element that detects that external light has entered the optical case. When the external light detection light receiving element receives a predetermined amount of light, the control unit The laser light source is turned off or the light emission period of the laser light source is lengthened.
The box according to the present invention is an optical bench on which a labyrinth wall is erected.

  According to the present invention, an optical case with an optical cover is attached and the inside is a dark box, a laser light source disposed in the optical case, and light emitted from the laser light source is scattered by smoke particles present in a smoke detector. A smoke detector comprising: a fire detection light receiving element that receives light; and a control unit connected to the laser light source and the fire detection light receiving element. An open detection unit having a light receiving element for detection is provided, and the control unit is configured such that when the external light due to an increase in diffracted light at the time of closing the lid, the output of the light receiving element for detecting an optical axis deviation exceeds a predetermined light amount, Alternatively, when the open signal of the open detector is received, the laser light source is turned off, or the light emission cycle is lengthened.

  Since the present invention is configured as described above, when the optical cover is opened, the opening detection unit detects the opening and outputs it to the control unit, so the control unit turns off the laser light source, or The light emission period of the laser light source is made longer than when the lid is closed. Therefore, unlike the conventional case, the safety of the eyes of the worker can be improved.

FIG. 2 is a configuration diagram of a smoke detector according to the first embodiment. FIG. 3 is a cross-sectional view of a smoke detection unit. FIG. 4 is a bottom view of the optical cover. These are the enlarged views which show an open | release detection part. FIG. 3 is a block diagram of the first embodiment. These are the enlarged views which show another open | release detection part. These are the enlarged views which show another open | release detection part. These are the enlarged views which show another open | release detection part. These are top views which show 3rd Embodiment of this invention. These are block diagrams of 3rd Embodiment. These are the flowcharts of 3rd Embodiment. FIG. 10 is a block diagram of a fourth embodiment of the present invention. FIG. 10 is a block diagram of a fifth embodiment of the present invention.

A first embodiment of the present invention will be described with reference to FIGS.
Reference numeral 1 denotes a sampling tube type smoke detector, 2 denotes an optical case whose inside is a dark box, 3 denotes a fan for sending air to be detected to the optical case 2, and 5 denotes a filter provided in the pipe 4.

  Reference numeral 11 denotes a light emitting element disposed in the optical case 2 and connected to the power supply unit 14. For example, a laser light source is used as the light receiving element. Reference numeral 12 denotes a light receiving element such as a photodiode. The light receiving element 12 receives scattered light caused by smoke particles existing in the smoke detector 25, and the light from the light emitting element 11 receives light from the light emitting element 11. It is disposed at a position where light does not enter directly. Reference numeral 14 denotes a power supply unit that supplies power to the fan 3 and the airflow sensor 13 that measures the air flow rate, and reference numeral 15 denotes a fire determination unit.

  The fire discriminating unit 15 includes an amplification circuit 41 that amplifies the output signal S of the light receiving element 12, an A / D converter that converts the amplified signal to a detection level, and fires when the detection level exceeds a preset threshold value. The control circuit (microcomputer) 42 performs integrated control.

  The optical case 2 includes a box 21, and the opening of the box 21 is closed by an optical cover 30. Therefore, the inside of the optical case 2 is, for example, a matte black and is a so-called dark box. A stray light portion 22 is provided in the box 21 at a position facing the light emitting element 11.

  Reference numeral 24 denotes a condensing lens, and the condensing lens 24 condenses the light emitted from the light emitting element 11 on a curved surface portion of an optical trap 23 provided in the stray light portion 22. Reference numeral 25 denotes a smoke detecting section that allows air to pass therethrough, and 26 denotes an aperture provided at an appropriate interval.

  The optical case 2 includes an opening detection unit 33. The opening detection unit 33 includes a short-circuit pin 33a provided on the element substrate 31 in the box body 21, and a short-circuit connector 33b provided on the inner surface of the optical cover 30 and inserted into the short-circuit pin 33a. (See FIG. 4).

  The open detection unit 33 is not limited to the above. For example, the open detection unit 33 is opposite to the above embodiment, that is, the short-circuit connector 33b is provided in the box body 21, and the short-circuit connector 33b is opposed to the inner surface of the optical cover 30. Then, the element substrate 31 on which the short-circuit pin 33a is mounted may be disposed (see FIG. 6).

  Further, the opening detection unit 35 can also be constituted by a switch body 35a provided on the element substrate 31 and a projection 35b provided on the inner side of the optical cover 30 so as to face the switch body 35 (FIG. 7). reference). In this case, in the closed state, the projection 35b presses the switch main body 35a to be switched on. However, in the open state, the pressing of the switch main body 35a is released, so that the switch is turned off.

  Furthermore, the open detection part 38 can also be comprised from the magnetic force sensor 38a provided in the back side of the element substrate 31, and the magnet 38b provided in the surface side of the optical cover 30 (refer FIG. 8). In this case, in the closed state, the magnet 38b is switched on close to the magnetic force sensor 38a. However, in the opened state, the magnet 38b is separated from the magnetic force sensor 38a, and is thus switched off.

Next, the operation of the present embodiment will be described.
At the time of fire monitoring, the box body 21 is closed by the optical cover 30 and the optical case 2 is in a dark box state. The light emitting element (laser light source) 11 irradiates the stray light portion 22 with laser light, and most of the laser light is sufficiently attenuated by being reflected by the curved surface portion of the optical trap 23 a plurality of times. A part exists as diffracted light in the smoke detector.

  When a fire occurs, smoke particles are contained in the air flow supplied to the optical case 2, and the laser light is scattered by the smoke particles, and the scattered light enters the fire detection light receiving element 12. Therefore, the light receiving element 12 sends a detection signal to the control unit (microcomputer) 42 via the amplifier circuit 41. If it does so, the fire discrimination | determination part of this control part 42 will judge whether it is a fire, and will operate an alarm device.

At the time of the fire monitoring, when the optical cover 30 is removed and the box body 21 is opened, the short-circuit pin 33a is separated from the short-circuit connector 33b and becomes non-conductive, so that the open detection unit 33 sends an open detection signal to the control unit 42. Send it out.
Then, since the controller 42 turns off the light emitting circuit 43 or the power supply circuit, the light emission of the light emitting element 11 is stopped (turned off) before the optical cover 30 is completely opened. Therefore, it is safe because the laser beam does not enter the eyes of the worker.

In the embodiment described above, the light is turned off when the control unit open detection unit 33 sends the open detection signal to the control unit 42. However, it is not always necessary to turn off the light.
For example, instead of turning off the light, the laser light output of the light emitting element 11 is weakened to such an extent that it does not adversely affect the eyes, or the light emission period is longer than usual, for example, the light emission period is changed from 3 seconds to 3 seconds. It may be changed to 60 minutes (60 times).

A second embodiment of the present invention will be described.
The difference between this embodiment and the first embodiment is the control method.
At the time of normal monitoring in which the optical axis deviation of the light emitting element 11 does not occur, most of the laser light of the light emitting element 11 is sufficiently attenuated by the optical trap 23 or the like, and the light receiving element 12 has a detection level including some diffracted light. Is being received.
On the other hand, at the time of monitoring that the optical axis shift of the light emitting element 11 occurs, the amount of the laser light of the light emitting element 11 attenuated by the optical trap 23 or the like is reduced, and the light receiving element 12 has a larger optical axis than when the optical axis is normal. The detection level including the diffracted light is received.
That is, in this embodiment, when the optical axis of the light emitting element 11 is not at the designed position (optical axis deviation) when the lid is closed during fire monitoring, the diffracted light increases, and the fire detecting light receiving element 12 The output increases and exceeds the threshold value (reference value).

The threshold value (reference value) is set to a light reception level lower than the fire level. When a light reception output exceeding the reference value is sent to the control unit (microcomputer) 42 via the amplifier circuit 41, The control unit 42 determines that “the optical axis is abnormal” (optical axis deviation).
This determination of the optical axis deviation is performed when the level rises slowly over several hours from the detection level of the light receiving element 12 during normal monitoring until it exceeds the threshold (reference value), for example. Accordingly, in the event of a fire, the light axis rapidly rises, for example, within several tens of seconds from the detection level of the light receiving element 12 during normal monitoring until the fire threshold is exceeded, so that it is not determined that the optical axis is deviated.

  When the optical axis shift occurs, there is a high possibility that the laser light or its diffracted light will diffusely reflect inside the dark box and enter the eyes of the operator when the lid is opened. When the output of the laser light source is small and the optical axis is at the design position, even if there is no safety problem for the operator, the problem may occur if the optical axis shift occurs.

In the second embodiment, the control unit 42 determines that the output of the fire detection light receiving element 12 slowly increases over a long time due to an increase in diffracted light at the time of closing and becomes equal to or more than a threshold value, and determines that it is “abnormal”. When the open signal of the open detector 33 or the output of the fire detecting light receiving element 12 is abnormal, the light emitting element 11 (laser light source) is turned off. This turn-off can ensure the safety of the eyes of the worker.
As in the first embodiment, instead of turning off the light, the laser light output of the light emitting element 11 may be lowered, or the light emission period may be longer than in the normal case (standard).

A third embodiment of the present invention will be described with reference to FIGS. 9 to 11. The same reference numerals as those in FIGS. 1 to 8 have the same names and functions.
The main differences between this embodiment and the first embodiment are that a scattered light spot type smoke detector is used as a smoke detector, and that a light receiving element for detecting outside light and optical axis deviation as an open detector. Is used.

  The scattered light spot type smoke detector optical case 2 includes an optical stand (box body) 47 in which a labyrinth wall 46 is erected and a lid (optical cover) (not shown). By attaching this lid to the upper end surface of the labyrinth wall 46 of the optical bench 47, a dark box is formed. The smoke detector 25 of the sensor is surrounded by a labyrinth wall 46, and the laser light emitted from the light emitting element 11 attenuates while colliding with the labyrinth wall 46. Since the laser light is shielded by the light shielding wall 49, it cannot directly enter the light receiving element 12.

  An opening detector 50 is provided on the optical bench 47. This open detection unit 50 is a light receiving element 50 for detecting external light and optical axis misalignment disposed between the labyrinth walls 46. When the external light enters the smoke detecting unit 25 and the light from the light emitting element 11. When the axis is not at the designed position (optical axis deviation), the signal is output to the amplifier circuit 51. Then, the amplifying circuit 51 sends outside light and an optical axis deviation detection signal to the control unit (microcomputer) 42.

Next, the operation of this embodiment will be described.
At the time of fire monitoring, the box body 21 is closed by the optical cover, and the optical case 2 is in a dark box state. The light emitting element (laser light source) 11 irradiates laser light toward the smoke detecting section 25, and most of the laser light is reflected by the side wall surface of the labyrinth wall 46 a plurality of times and sufficiently attenuated. A part exists as diffracted light in the smoke detector.

  When a fire occurs, an air flow containing smoke particles flows into the optical case 2 from between the labyrinth walls 46. The laser light emitted from the laser light source 11 is scattered by the smoke particles in the air flow, and the scattered light enters the fire detecting light receiving element 12. Therefore, the light receiving element 12 sends a detection signal to the control unit (microcomputer) 42 via the amplifier circuit 41. If it does so, the fire discrimination | determination part of this control part 42 will judge whether it is a fire, and will operate an alarm device.

  During the fire monitoring (S1), when the optical cover is removed and the optical case 2 is opened (S2, S3), external light is incident on the light receiving element 50 for detecting outside light and optical axis deviation. Since the amount of received light is equal to or greater than the predetermined amount of received light, the opening detection unit 50 sends an opening detection signal to the control unit 42. Then, the control unit 42 instructs the light emission circuit 43 to change the light emission cycle, and the light emitting element 11 has a light emission cycle (for example, a pulse at intervals of 3 minutes) longer than the light emission cycle (for example, a pulse at intervals of 3 seconds). To emit light. By making the light emission period longer in this way, it is possible to make the eyes of the worker safe. However, since the lighting state can be maintained without turning off the light, it may be convenient for inspection. Note that instead of turning off the light, the output of the light emitting element 11 may be reduced.

  When the optical case (optical stage) 2 is not opened, the control unit 42 confirms the external light received light output output and the optical axis shift determination result based on the output of the external light and the optical axis shift detection light receiving element 50. Confirmation (S4), it is determined whether or not there is an abnormality (S5).

If it is not abnormal, a normal light emission period change instruction is sent to the light emitting circuit 43 (S6), and the light emitting element 11 is turned on with a normal light emission period.
In the case of abnormality, an abnormal light emission period change instruction is sent to the light emitting circuit 43 (S7), and the light emitting element 11 is turned on with an abnormal light emission period.
Based on the lighting state of the light emitting element 11, it is possible to perform the optical axis deviation determination and the fire determination when the cover is closed (S9).

  In the third embodiment, since the optical case is provided with an open detection unit having a light receiving element for detecting external light and optical axis deviation in the optical case, the control unit is based on an increase in diffracted light when the lid is closed. When the output of the light receiving element for detecting external light and optical axis deviation exceeds a predetermined light amount, or when receiving an open signal of the open detector, the laser light source is turned off or the light emission period is set. It can be longer than when the lid is closed.

A fourth embodiment of the present invention will be described with reference to FIG. 12. The same reference numerals as those in FIGS. 1 to 11 have the same names and functions.
The fourth embodiment is provided with the opening detection unit 33 of the first and second embodiments and the opening detection unit 50 of the third embodiment, and includes two opening detection units of different types. ing.

  In the fourth embodiment, the external light and the optical axis deviation detection light receiving element 50 are input to the control unit 42 as external light, an optical axis deviation detection signal, and an open detection signal of the open detection part 33. It is possible to detect opening and to detect optical axis deviation when the lid is closed.

A fifth embodiment of the present invention will be described with reference to FIG. 13. The same reference numerals as those in FIGS. 1 to 12 have the same names and functions.
In the fifth embodiment, the open detection unit 33 of the fourth embodiment is provided in the power supply circuit 55 that supplies power to the light emitting circuit 43, or is provided in the light emitting circuit 43.
In this embodiment, when the opening detection unit 33 detects the opening of the optical cover, the power supply circuit 55 or the light emitting circuit 43 is turned off, and the light emission of the light emitting element is stopped.

DESCRIPTION OF SYMBOLS 1 Sampling tube type smoke detector 2 Optical case 11 Light emitting element 12 Light receiving element 21 Box body 25 Smoke detection part 30 Optical cover 33 Opening detection part 38 Opening detection part 42 Control part 47 Optical stand 50 Opening detection part

Claims (6)

An optical case having a dark box inside, a laser light source disposed in the optical case, a light receiving element that receives light scattered by smoke particles in which light emitted from the laser light source is present in the smoke detecting unit, and the light receiving device In a smoke detector comprising: a light receiving amplification circuit that amplifies an output signal of an element; and a fire determination unit that detects a fire when the detection level obtained by A / D converting the amplified output signal is equal to or higher than a threshold value,
The optical case is composed of an optical cover and a box,
An opening detection unit that detects the opening of the optical cover, and a control unit that turns off the laser light source or makes the light emission period of the laser light source longer than when the lid is closed by an output signal of the opening detection unit. A smoke detector. An optical case having a dark box inside, a laser light source disposed in the optical case, and a light receiving element for fire detection in which light emitted from the laser light source receives scattered light by smoke particles present in the smoke detecting unit; A smoke detector comprising: a light receiving amplification circuit that amplifies an output signal of the light receiving element; and a fire determination unit that performs a fire determination when a detection level obtained by A / D converting the amplified output signal is equal to or higher than a threshold value.
The optical case is composed of an optical cover and a box,
The detection of the opening of the optical cover and the output of the light receiving element for detecting the fire due to an increase in diffracted light when the cover is closed are judged to be abnormal when the output is greater than or equal to a threshold value. A smoke detector, comprising: a control unit that turns off the laser light source or makes the light emission period of the laser light source longer than normal when the output of the light receiving element for detection is abnormal.   When the short-circuit pin provided on the optical cover and the short-circuit connector provided on the box body are turned off, the open detection unit turns off the laser light source or emits light from the laser light source. The smoke detector according to claim 1, wherein the smoke detector is lengthened.   The open detection unit includes an external light detection light receiving element that detects that external light has entered the optical case. When the external light detection light receiving element receives a predetermined amount of light, the control unit detects the laser light source. The smoke detector according to claim 1 or 2, wherein the light source is turned off or the light emission period of the laser light source is lengthened.   The smoke detector according to claim 1, 2, 3, or 4, wherein the box is an optical bench on which a labyrinth wall is erected. An optical case with an optical cover attached and a dark box inside, a laser light source disposed in the optical case, and light emitted from the laser light source receive scattered light by smoke particles present in the smoke detector. In a smoke detector comprising a fire detecting light receiving element, and a control unit connected to the laser light source and the fire detecting light receiving element,
The optical case is provided with an open detector having a light receiving element for detecting external light and optical axis deviation,
The control unit, when the output of the outside light due to an increase in diffracted light at the time of closing the lid, the output of the light receiving element for detecting the optical axis deviation becomes a predetermined light amount or more, or when the opening signal of the opening detection unit is received, A smoke detector characterized in that the laser light source is turned off or the light emission period is made longer than normal.

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