JP2008250851A - Photoelectric smoke detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric smoke detector for preventing any false report or unsuccessful report even when smoke density rapidly increases or decreases. <P>SOLUTION: This photoelectric smoke detector is provided with a first light emitting device for generating the rays of light with a first emission pulse width in a smoke detection space; a second light emitting device equipped with an optical axis different from the optical axis of the first light emitting device in the smoke detection space for generating the rays of light with second emission pulse width being pulse width which is narrower than the first emission pulse width, and for emitting the rays of light within the time of the first emission pulse width, and for generating the rays of light having the same wavelength distribution as that of the rays of light generated by the first light emitting device; a light receiving element whose crossing angle with the optical axis of the first light emitting element and whose crossing angle with the optical axis of the second light emitting are different; a separation means for separating the output signal of the light emitting device into the components of the rays of light emitted by the first light emitting device and the components of the rays of light emitted by the second light emitting device; and a disaster discrimination means for discriminating a fire on the basis of each output value output by the separation means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a photoelectric smoke detector.

As a conventional photoelectric smoke detector, two light emitting elements emit light at different timings (separate times), and the amount of light received by the light emitted by one light emitting element and the amount of light received by the light emitted by the other light emitting element There is known a photoelectric smoke detector that determines a ratio of the above and determines a fire based on the determined ratio (see, for example, Patent Document 1).
Japanese Patent No. 2966541

  In the above conventional example, since the two light emitting elements emit light at different times, strictly, the on-time received light output ratio cannot be detected.

  Therefore, when an insect or the like enters the labyrinth and the insect or the like quickly moves around, or when the smoke concentration suddenly rises or falls, fluctuations in output with respect to time increase. For this reason, the light reception output ratio increases due to the time lag of the light emission period of the two light emitting elements, which may cause malfunction or misreporting.

It is an object of the present invention to provide a smoke detector that does not generate false alarms or false alarms even when the smoke concentration rapidly increases or decreases.

The present invention includes a first light emitting element that generates light with a first emission pulse width in a smoke detection space, and an optical axis that is different from the optical axis of the first light emitting element in the smoke detection space. Then, light having a second light emission pulse width which is narrower than the first light emission pulse width is generated, and light is emitted within the time of the first light emission pulse width, and the first light emitting element is generated. Light reception in which the crossing angle between the second light emitting element that generates light having the same wavelength distribution as the light, the optical axis of the first light emitting element, and the optical axis of the second light emitting element is different A separation means for separating the output signal of the element, the light output from the first light emitting element into a component of the light emitted from the first light emitting element, and a component output from the second light emitting element; It is a photoelectric smoke detector having a fire discrimination means for discriminating a fire based on a value.

According to the present invention, there is an effect that no false alarm or misreport occurs even if the smoke concentration in the smoke detection space increases or decreases rapidly.

  The best mode for carrying out the invention is the following examples.

  FIG. 1 is a block diagram showing a circuit configuration of a photoelectric smoke detector 100 that is Embodiment 1 of the present invention.

  FIG. 2 is a diagram illustrating signal processing of the photoelectric smoke detector 100 in the first embodiment.

  The photoelectric smoke detector 100 includes a case C1 having a smoke detection space 10, a first light emitting element 11, a second light emitting element 12, a light receiving element 13, a signal processing circuit 20, and a control circuit 30. The transmitter / receiver circuit 40, the depolarization circuit 50, the operation indicator lamp circuit 60, and the constant voltage circuit 70 are provided.

  The first light emitting element 11 generates light with a first light emission pulse width W1 in the smoke detection space 10.

  The second light emitting element 12 is a second light emission having a pulse width narrower than the first light emission pulse width W1 in the smoke detection space 10 and having an optical axis different from the optical axis of the first light emitting element 11. Light having a pulse width W2 is generated and emitted within the time of the first light emission pulse width W1.

  The 1st light emitting element 11 and the 2nd light emitting element 12 are comprised, for example by LED which light-emits the infrared rays of the same wavelength mutually. That is, the light generated by the first light emitting element 11 and the light emitted by the second light emitting element 12 have the same wavelength distribution.

  The light receiving element 13 is different in the crossing angle with the optical axis of the first light emitting element 11 and the crossing angle with the optical axis of the second light emitting element 12 (the two light emitting elements 11 and 12 are different from each other). It is a light receiving element having an optical axis angle) and sensitivity to infrared rays.

  The signal processing circuit 20 includes an amplifier circuit 21, band pass filters 22 and 24, and A / D converters 23 and 25.

  The amplifier circuit 21 amplifies the output signal of the light receiving element 13.

  The band pass filters 22 and 24 separate the signal output from the amplifier circuit 21 into a light component emitted from the first light emitting element 11 and a component emitted from the second light emitting element 12. The center frequency fc of the bandpass filter 22 is, for example, 100 Hz, and the center frequency fc of the bandpass filter 24 is, for example, 1 KHz. That is, if the center frequency of the filter is extremely low, it is affected by external light or the like, so the center frequency fc is set to 100 Hz and 1 KHz, for example. That is, the band pass filters 22 and 24 are examples of separation means.

  The A / D converters 23 and 25 are circuits that convert the analog signals separated and output by the bandpass filters 22 and 24 into detection levels.

  The control circuit 30 includes a CPU, controls the entire photoelectric smoke detector 100, and determines fire based on the detection levels output from the A / D converters 23 and 25. The control circuit 30 is an example of a fire determination unit. That is, the control circuit 30 separates the received light signal into a component having a short pulse width and a component having a long pulse width, and then performs A / D conversion, and makes a fire determination based on the component ratio of the detection level.

  The transmission / reception circuit 40 is a circuit for transmitting / receiving a signal to / from a fire receiver (not shown). The operation indicator light circuit 60 is a circuit that displays the operation state of the photoelectric smoke detector 100 by turning on a predetermined indicator light so that the operation state of the photoelectric smoke detector 100 can be immediately recognized from the outside. It is. The constant voltage circuit 70 is a circuit that supplies a predetermined constant voltage to each circuit provided in the photoelectric smoke detector 100.

  Next, the operation of the first embodiment will be described.

  FIG. 3 is a diagram illustrating an output signal during normal monitoring and an output signal when smoke or the like enters the smoke detection space 10 in the first embodiment.

  The output value (initial value) A0 is the value of the output signal output by the band-pass filter 22 when the light emitting element 11 emits light at the start of monitoring when smoke or foreign matter does not exist in the smoke detection space 10 and during normal monitoring. The output value (sample value) A1 is the value of the output signal output by the band-pass filter 22 when the light emitting element 11 emits light when smoke or the like enters the smoke detection space 10.

  Similarly to the output value A0, the output value (initial value) B0 is the value of the output signal output from the bandpass filter 24 when the light emitting element 12 emits light, and the output value (sample value) B1 is the smoke detection space. The value of the output signal output from the band pass filter 24 when the light emitting element 12 emits light when smoke or the like enters 10.

The control circuit 30 makes a fire determination with the following three elements.
(1) A1-A0,
(2) B1-B0,
(3) Relationship between (1) and (2) (ratio, difference, etc.).

  FIG. 4 is a flowchart illustrating the operation of the first embodiment.

  First, the light emitting elements 11 and 12 are controlled in S1, and the light emitting elements 11 and 12 are caused to emit light in S2, and the light receiving element 13 receives signals. In S3, the amplifier circuit 21 amplifies the signal. In addition, when it is not necessary to amplify the received light signal, it is not amplified.

  In S4, the A / D converters 23 and 25 capture the signals that have passed through the bandpass filters 22 and 24 having different passbands, respectively. That is, the signal amplified by the amplifier circuit 21 is separated. In S5, the difference value X = A1 (sample value) −A0 (initial value) and the difference value Y = B1 (sample value) −B0 (initial value) are calculated.

  In S7, the difference value X is compared with the threshold value TA1, and if it is determined that the difference value X is equal to or less than the threshold value TA1, the difference value Y and the threshold value TB1 are compared in S8, and the difference value Y Is determined to be normal (non-fire) in S9.

  If it is determined in S8 that the difference value Y is greater than the threshold value TB1, the ratio value Y / X is compared with the threshold value TR1 in S10, and if it is determined that Y / X is equal to or less than the threshold value TR1. In S11, the fact that it is normal (non-fire) is transmitted to the fire receiver.

  In S10, Y / X and threshold value TR1 are compared. If it is determined that Y / X is larger than threshold value TR1, Y / X and threshold value TR2 are compared in S12, and Y / X is equal to or less than threshold value TR2. If it is determined that it is, the fact that a fire has occurred is transmitted to the fire receiver in S13.

  If it is determined in S12 that Y / X is larger than the threshold value TR2, in S14, a foreign matter such as an insect enters near the point b of the smoke detection space 10 in FIG. Then, it is extremely smaller than Y by the light emitting element 12, and a detection result is abnormal is transmitted to the fire receiver.

  On the other hand, if it is determined in S7 that the difference value X is larger than the threshold value TA1, Y / X is compared with the threshold value TR3 in S21, and if it is determined that Y / X is equal to or less than the threshold value TR3, In S22, a foreign matter such as an insect enters the vicinity of point a in the smoke detection space 10 in FIG. 2, so that the Y value by the light emitting element 12 becomes extremely smaller than X by the light emitting element 11, and the detection result is abnormal. To the fire receiver.

  If it is determined in S21 that Y / X is larger than the threshold value TR3, in S23, Y / X is compared with the threshold value TR4. If it is determined that Y / X is equal to or less than the threshold value TR4, in S24, Send to the fire receiver that a fire has occurred. If it is determined in S23 that Y / X is larger than the threshold value TR4, in S25, an abnormality occurs in the Y detection circuit by the light emitting element 12 of the smoke detector 100, and a fire is detected that the detection result is abnormal. Send to receiver.

  Therefore, according to the first embodiment, even if the smoke concentration in the smoke detection space suddenly increases or decreases, and even if foreign matter such as insects enters the smoke detection space, the light emission timing and the light emitting element by the light emitting element 11 No misreporting or misreporting occurs due to the difference in the light emission timing by 12.

  According to the first embodiment, two light emitting elements having the same wavelength are caused to emit light simultaneously with different light emission waveforms, and the received light output separated from the waveform is analyzed. Thus, two types of scattered light output information can be obtained at the same time. Fire detection time is shorter than technology.

Furthermore, it is possible to obtain an accurate received light output ratio of the two light emitting elements, and avoid false or misreporting.

  FIG. 5 is a diagram illustrating signal processing of the photoelectric smoke detector 200 according to the second embodiment of the present invention.

  The circuit configuration of the photoelectric smoke detector 200 is basically the same as that of the photoelectric smoke detector 100. In the photoelectric smoke sensor 100, digital filters 27 and 28 are provided instead of the bandpass filters 22 and 24, and an A / D converter 26 is provided instead of the A / D converters 23 and 25. This is different from the photoelectric smoke detector 100.

  The digital filter 27 has a center frequency fc of, for example, 100 Hz and extracts the light component emitted by the light emitting element 11, and the digital filter 28 has a center frequency fc of, for example, 1 KHz, and the light component emitted by the light emitting element 12. To extract.

  Next, the operation of the second embodiment will be described.

  FIG. 6 is a flowchart showing the operation of the photoelectric smoke detector 200.

  The operation of the second embodiment is basically the same as the operation of the first embodiment shown in FIG. 4, but in the flowchart shown in FIG. 4, the processes of S31 and S32 are executed instead of the processes of S4 and S5. . That is, in S31, the A / D converter 26 converts the output signal of the amplifier circuit 21 into a detection level, and in S32, the digital filter 27 only outputs a signal having a center frequency of 100 Hz (light component emitted from the light emitting element 11). The digital filter 28 passes only a signal having a center frequency of 1 kHz (light component emitted by the light emitting element 12).

  As in the first embodiment, for example, in S42, if it is determined that XY is larger than TR2, a result that a foreign matter such as an insect has entered near the point a of the smoke detection section 10 shown in FIG. 2 in S14. Since the light emitting element 11 is blocked and the light emitting element 12 is reflected, the fact that the detection result is abnormal is transmitted to the fire receiver.

  Further, for example, if it is determined in S42 that XY is smaller than TR3, similarly, an insect has entered near the point b in the smoke detection space 10 shown in FIG. 2 and both light emitting elements are reflected. recognize.

  Further, for example, in S52, if XY is larger than TR4 and Y is substantially 0, it is recognized that the light emitting element 12 is disconnected.

  Also in the second embodiment, two light emitting elements having the same wavelength are caused to emit light simultaneously with different light emission waveforms, and the light reception output is analyzed, so that two types of scattered light output information can be obtained at the same time. short.

Furthermore, it is possible to obtain an accurate received light output ratio of the two light emitting elements, and avoid false or misreporting.

  FIG. 7 is a flowchart showing the operation of the third embodiment of the present invention.

In the third embodiment, in the processes of S10, S12, S21, and S23 shown in FIG. 4, the calculation process is performed using the difference value of “XY” instead of “X / Y”. It is an example. In this case, the threshold values TR1, TR2, TR3, TR4 may be changed according to the actual situation.

  FIG. 8 is a flowchart showing the operation of the fourth embodiment of the present invention.

  In the fourth embodiment, in the processing of S10, S12, S21, and S23 shown in FIG. 6 in the second embodiment, calculation processing is performed using the difference value “XY” instead of “X / Y”. It is an example. In this case, the threshold values TR1, TR2, TR3, TR4 may be changed according to the actual situation.

  Next, a determination example of the photoelectric smoke detector in the above embodiment will be described.

  FIG. 9 is a diagram showing a result of confirming by simulation that the inventor of the present case can discriminate various states of the photoelectric smoke detector.

  The inventor of the present case confirmed by simulation that various states of the photoelectric smoke detector can be discriminated from the received light waveform at the time of normal operation, when smoke particles or foreign objects enter, and at the time of failure according to the following threshold values.

  When the ratios shown in FIGS. 4 and 6 are used, the results are as follows, and the simulation results are shown in FIG. 9 (1).

  The conditions in this case are Xmax = 200 and Ymax = 200. The threshold values are TA1 = 20, TB1 = 30, TR1 = 1.5, TR2 = 10, TR3 = 1.5, and TR4 = 5.

  When the differences shown in FIGS. 7 and 8 are used, the results are as follows, and the simulation results are shown in FIG. 9 (2).

The conditions in this case are Xmax = 200 and Ymax = 200. The threshold values are TA1 = 50, TB1 = 10, TR1 = 15, TR2 = 20, TR3 = 10, TR4 = 50.

It is a block diagram which shows the photoelectric smoke detector 100 which is Example 1 of this invention. It is a figure which shows the signal processing of the photoelectric smoke detector 100 in Example 1. FIG. In Example 1, it is a figure which shows the output signal at the time of normal monitoring, and the output signal at the time of the penetration | invasion of the smoke etc. to the smoke detection space 10. FIG. 3 is a flowchart showing the operation of the first embodiment. It is a figure which shows the signal processing of the photoelectric smoke detector 200 which is Example 2 of this invention. 3 is a flowchart showing the operation of the photoelectric smoke detector 200. It is a flowchart which shows operation | movement of Example 3 of this invention. It is a flowchart which shows operation | movement of Example 4 of this invention. It is a figure which shows the result of having confirmed by simulation that the inventor of this case can discriminate | determine the various states of a photoelectric smoke detector.

Explanation of symbols

100: photoelectric smoke detector,
C1 ... Case,
10 ... smoke detection space,
11 ... 1st light emitting element,
12 ... Second light emitting element,
13: Light receiving element,
20: Signal processing circuit,
21 ... Amplifier circuit,
22: Band pass filter,
23 ... A / D converter,
24. Bandpass filter,
25 ... A / D converter,
30 ... control circuit,
40: Transmission / reception circuit.

Claims (1)

A first light emitting element for generating light with a first emission pulse width in a smoke detection space;
In the smoke detection space, the optical axis different from the optical axis of the first light emitting element is provided, and light having a second emission pulse width that is narrower than the first emission pulse width is generated, A second light emitting element that emits light within the time of the first light emission pulse width and generates light having the same wavelength distribution as the light generated by the first light emitting element;
A light receiving element having a crossing angle with the optical axis of the first light emitting element and a crossing angle with the optical axis of the second light emitting element;
Separating means for separating an output signal of the light receiving element into a component of light emitted from the first light emitting element and a component emitted from the second light emitting element;
A fire discriminating means for discriminating a fire based on each output value output by the separating means;
A photoelectric smoke detector characterized by comprising:

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