JP2010072851A - Photoelectric smoke detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric smoke detector capable of preventing detection errors. <P>SOLUTION: The photoelectric smoke detector includes: a housing 21 having a plurality of wall sections that allow in smoke from the outside while shutting direct light from the outside; a light emitting unit for applying light to the inside of the housing 21; a light receiving unit for receiving light scattered by the smoke allowed into the housing 21; a pocket section provided in at least the wall section located on the underside among the plurality of wall sections, in such a way that the pocket section opens upwards to trap foreign matter intruding into the housing 21; and a vibration generating means 3 for vibrating the housing 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a housing having a plurality of walls that allow external smoke to flow in and blocks direct light from the outside, a light emitting unit that irradiates light inside the housing, and smoke that has flowed into the housing. And a light receiving unit that receives the scattered light of the light.

  Such a photoelectric smoke detector uses a fact that a smoke detection chamber formed by a housing is provided with a light emitting unit for irradiating light and a light receiving unit for receiving light in the smoke detection chamber, and light is scattered by smoke. To detect smoke. That is, normally, since the direct light irradiated from the light emitting unit does not go to the light receiving unit, the light is not detected by the light receiving unit. On the other hand, when a fire occurs, the smoke generated by the fire flows into the housing, and the direct light emitted from the light emitting unit is scattered by the smoke, so that the scattered light is detected by the light receiving unit.

  Conventionally, in this type of photoelectric smoke detector, there is one that has provided an insect net on the outside of the wall portion to prevent false detection due to insects entering the smoke detection chamber (for example, Patent Document 1). reference.).

JP-A-9-231485

  By the way, the insect net used in the conventional photoelectric smoke detector is provided with a gap that does not affect the inflow of smoke so as not to hinder the smoke detection performance. For this reason, foreign matters such as small dust may enter the smoke detection chamber through the gap. At this time, foreign matter may adhere to the smoke detection chamber, and the direct light emitted from the light emitting unit may be irregularly reflected by the foreign matter, and the intensity of the irregularly reflected light is comparable to the intensity of the scattered light from the smoke, There was a problem of causing false detection.

  This invention is made | formed in view of the said actual condition, The objective is to provide the photoelectric smoke detector which can prevent a misdetection.

  The first characteristic configuration of the photoelectric smoke detector according to the present invention is a housing having a plurality of walls that allow external smoke to flow in and blocks direct light from the outside, and light emission that irradiates light inside the housing. A light receiving portion that receives the scattered light of the light due to the smoke flowing into the housing, and a wall portion that is located at least on the lower side of the plurality of wall portions in a state where the housing is attached to the wall. It is provided with a pocket portion that is provided so as to open upward and captures foreign matter that has entered the inside of the housing, and vibration generating means that vibrates the housing.

  According to this configuration, even if the foreign matter enters the smoke detection chamber formed by the housing and adheres to the location where the direct light irradiated from the light emitting unit hits in the smoke detection chamber, the foreign matter is smoked by the vibration generated by the vibration generating means. It drops off from the location in the detection chamber and is captured by a pocket portion that opens upward. For this reason, the irregular reflection of the light by a foreign material can be prevented, and a false detection can be prevented. In addition, foreign matter captured by the pocket portion can be blocked from the air or the like by the pocket portion even when external air or the like flows into the housing. For this reason, it can prevent that a foreign material rises in the inside of a housing, and a foreign material adheres again in a smoke detection chamber.

  According to a second characteristic configuration of the present invention, the housing includes a light shielding portion that blocks direct light from the light emitting portion toward the light receiving portion, and the pocket portion is provided below the light shielding portion.

  In general, in a photoelectric smoke detector, if a foreign substance adheres to a light shielding part that blocks direct light from a light emitting part, the direct light emitted from the light emitting part is irregularly reflected by the foreign substance and easily causes erroneous detection. For this reason, when a light shielding part is provided as in this configuration, even if a foreign object adheres to the light shielding part that blocks direct light from the light emitting part toward the light receiving part, It falls off and is captured by a pocket part provided below the light shielding part. Therefore, it is possible to prevent erroneous detection by preventing irregular reflection of light by a foreign substance. And since the pocket part is provided under the light-shielding part, it is easy to catch the foreign material which fell from the light-shielding part.

The third characteristic configuration of the present invention further comprises control means for controlling the operation of the vibration generating means,
The control means is to operate the vibration generating means for a certain period when a preset condition is satisfied.

  According to this configuration, when the preset condition is satisfied, the vibration generating unit is operated for a certain period. Therefore, the vibration generating unit is always operated by operating the vibration generating unit for a certain period at an appropriate timing. Compared to the above, while extending the life of the battery that operates the photoelectric smoke detector, it is possible to prevent misdetection by preventing irregular reflection of light by a foreign substance.

  According to a fourth characteristic configuration of the present invention, the control means determines that the condition is satisfied when a predetermined period elapses after the vibration generating means is operated.

  According to this configuration, after a predetermined period of time has elapsed after the vibration generating means has been operated for a certain period of time, the use of the smoke detector causes foreign matters such as small dust to enter and accumulate in the smoke detection chamber, and the smoke detection chamber It is considered that there is a high possibility of irregular reflection by foreign matter adhering to the surface. Therefore, when a predetermined period elapses after the vibration generating means is operated, the vibration generating means is operated again, thereby preventing irregular reflection of light by a foreign substance and preventing erroneous detection.

  A fifth characteristic configuration of the present invention is that the control means determines that the condition is satisfied when the amount of the scattered light received by the light receiving unit is equal to or greater than a predetermined value.

  According to this configuration, when the amount of the scattered light received by the light receiving unit is equal to or greater than a predetermined value, the foreign matter adheres to the smoke detection chamber and is irregularly reflected by the foreign matter, and the case where the scattered light is scattered by the smoke. It is thought that either. Therefore, if the amount of scattered light received by the light receiving unit is greater than or equal to a predetermined value, the vibration generating means is once activated. After that, if the amount of scattered light received by the light receiving unit is greater than or equal to a predetermined value, the possibility of being scattered by smoke is high, and if the amount of scattered light is less than or equal to a predetermined value, it can be diffusely reflected by foreign matter. It is considered that the nature is high. For this reason, it is possible to prevent misdetection by distinguishing between irregular reflection due to foreign matter and scattering due to smoke.

  A sixth characteristic configuration of the present invention is that the vibration generating means is a speaker integrally attached to the housing.

  According to this structure, the structure which simplifies a structure can be achieved by using the speaker which emits an alarm sound also as a vibration generation means. In addition, since the speaker is integrally attached to the housing, it is easy to transmit the vibration of the speaker to the housing.

[First embodiment]
Hereinafter, an embodiment of a photoelectric smoke detector according to the present invention will be described with reference to the drawings. Here, the case where this invention is applied to the smoke detection part 2 in the fire alarm 1 is demonstrated.

  As shown in FIG. 2, the wall-mounted fire alarm 1 according to the present embodiment includes a smoke detection unit 2 that detects smoke, an alarm speaker 3 that emits an alarm sound such as a voice or a buzzer, an LED, and the like. And an alarm lamp 4 that lights or blinks the light. When the smoke detector 2 detects smoke, the fire alarm 1 determines, for example, whether the smoke concentration is higher or lower than a preset threshold value. If the smoke concentration exceeds the threshold value, the fire alarm 1 is determined to be a fire. Then, an alarm sound is emitted from the alarm speaker 3 and the alarm lamp 4 is turned on. The fire alarm 1 is provided with an alarm stop button 5, which can be operated to stop an alarm sound from the alarm speaker 3 and turn off the alarm lamp 4. Also, on the back of the fire alarm 1, there are an attachment part (not shown) for fixing the fire alarm 1 to a wall material, a battery storage part (not shown) for storing a battery for driving the fire alarm 1, etc. It is provided.

  As shown in FIGS. 1 to 3, the smoke detector 2 includes a housing 21. The housing 21 is attached to the substrate 31, and includes a bottom surface portion 21b, a partition portion 21c, a lid portion 21e, a bottom surface portion 21b and a partition portion 21c, and a rod-shaped member provided between the partition portion 21c and the lid portion 21e. 21a and the like. A speaker housing space for housing the alarm speaker 3 is formed above the partition portion 21c. An engaging portion 21d that engages with the alarm speaker 3 is formed in the partition portion 21c. Thereby, the alarm speaker 3 is integrally attached to the housing 21. A smoke detection chamber 22 for detecting smoke is formed between the bottom surface portion 21b and the partition portion 21c.

  A plurality of bowl-shaped wall portions 23 are provided in the housing 21 so as to surround the smoke detection chamber 22 over the entire length in the height direction of the smoke detection chamber 22. Thereby, the smoke from the outside can flow into the smoke detection chamber 22 while blocking the light from the outside. Each wall portion 23 is provided with its end portion directed in the same circumferential direction, and on the wall portion 23a provided at the lowest position of the wall portion 23 when the fire alarm 1 is attached to the wall. Is formed of a wall having the same height as the other wall portions 23, and is provided with a pocket portion 23b that opens upward. An insect screen 24 made of a wire mesh or the like is provided outside the wall portion 23 so that insects and the like do not enter the smoke detection chamber 22.

  In the wall-mounted fire alarm 1 as in the present embodiment, dust (an example of a foreign matter) that has entered the smoke detection chamber 22 accumulates downward. For this reason, by providing such a pocket portion 23b, dust that has entered the smoke detection chamber 22 can be efficiently captured. Further, the end portion of the wall portion 23a forming the pocket portion 23b on the side of the smoke detection chamber 22 is provided so as to face the same circumferential direction as the end portion of the wall portion 23 on the other smoke detection chamber 22 side. 1 flows in the direction opposite to the pocket 23b and flows in between the wall 23 on the right side of the wall 23a in FIG. Are configured to flow through the upper portion of the pocket portion 23b. For this reason, air or the like flowing from the outside does not flow into the pocket portion 23b, and dust once trapped in the pocket portion 23b does not rise. The opening width of the pocket portion 23b is preferably large within a range that does not hinder the inflow of smoke into the smoke detection chamber 22, thereby facilitating dust trapping.

  Inside the housing 21, a light emitting element 25 such as a light emitting diode that irradiates light such as near infrared rays to the smoke detection chamber 22, a photodiode as a light receiving portion that receives light from the smoke detection chamber 22, and the like. The light receiving elements 26 are provided so that their optical axes intersect with each other inside the smoke detection chamber 22. Further, a light shielding wall 27 as a light shielding part is provided between the light emitting element 25 and the light receiving element 26 so that direct light from the light emitting element 25 toward the light receiving element 26 can be blocked. For this reason, the light receiving element 26 does not normally receive the light emitted from the light emitting element 25, and can receive the scattered light of the light emitted from the light emitting element 25 due to the smoke only when the smoke flows into the smoke detection chamber 22. Become. The smoke detector 2 can detect the presence of smoke by detecting the scattered light.

  The light receiving element 26 is disposed above the light shielding wall 27 and the pocket portion 23b. In the wall-mounted fire alarm 1 as in this embodiment, dust easily enters the housing 21 from above. For this reason, by providing the light receiving element 26 and the pocket portion 23 b in this way, dust is less likely to enter the smoke detection chamber 22. Further, since the pocket portion 23 b is provided below the light shielding wall 27, it is easy to capture dust that has fallen from the light shielding wall 27.

  The alarm speaker 3 emits an alarm sound in the event of a fire, but is also used to vibrate the housing 21. That is, even when dust enters the smoke detection chamber 22 and adheres to the light shielding wall 27 by emitting a sound having a frequency lower or higher than the audible range, the dust is blocked by the vibration of the alarm speaker 3. Since the pocket portion 23b that is detached from the inside of the device 27 and falls and opens upward captures dust, it is possible to prevent irregular detection of light by dust and prevent erroneous detection. Therefore, the alarm speaker 3 also serves as vibration generating means for vibrating the housing 21. In addition, about the structure and function of the fire alarm 1 provided with the other smoke detection part 2, it is the same as that of a conventionally well-known fire alarm.

Next, the control configuration of the photoelectric smoke detector according to the present invention will be described.
A control means (not shown) such as a microcomputer for controlling the operation of the alarm speaker 3 as a vibration generating means is provided. The control means operates the alarm speaker 3 for a certain period to vibrate the housing 21 and then performs a predetermined operation. When the period elapses, it is determined that the condition is satisfied, and the alarm speaker 3 is activated.

  Specifically, as shown in FIG. 4, the light emitting element 25 irradiates light every 10 seconds, and the light receiving element 26 receives light emitted from the light emitting element 25. Then, the alarm speaker 3 is operated for a predetermined period to vibrate the housing 21 one second before the light emitting element 25 emits light with pulses. The timing and operating time for operating the alarm speaker 3 can be set and changed as appropriate. For example, as shown in FIG. 4, it can be set / changed according to the degree of dust accumulation, such as being operated once for one pulse irradiation or once for a plurality of pulse irradiations. Further, the alarm speaker 3 may be operated periodically (hour, day, week, month, year). The interval for periodically operating the alarm speaker 3 can be set and changed as appropriate. Furthermore, a temperature sensor (not shown) may be provided, and the alarm speaker 3 may be operated to vibrate the housing 21 when the temperature of the temperature sensor reaches a predetermined temperature. Accordingly, by appropriately setting the predetermined temperature, the alarm speaker 3 can be operated between the night and daytime or between winter and summer to vibrate the housing 21.

[Second Embodiment]
In this embodiment, a control configuration different from the configuration of the first embodiment will be described.
The control means is configured to operate the alarm speaker 3 for a certain period by determining that the condition is satisfied when the amount of scattered light received by the light receiving element 26 is equal to or greater than a predetermined value.

  Specifically, the light emitting element 25 irradiates light every 10 seconds, and the light receiving element 26 receives light emitted from the light emitting element 25. When the amount of scattered light received by the light receiving element 26 is equal to or greater than a threshold value for generating an alarm sound, the alarm speaker 3 is operated for a certain period to vibrate the housing 21. Next, when the light emitting element 25 irradiates light and the amount of scattered light received by the light receiving element 26 is still equal to or greater than the threshold value, it is considered that the light is likely to be scattered by smoke. Then, an alarm sound is emitted from the alarm speaker 3, and the alarm lamp 4 is turned on. When the amount of scattered light received by the light receiving element 26 falls below the threshold, it is considered that there is a high possibility of dust, so that no alarm sound is emitted from the alarm speaker 3 and the alarm lamp 4 is not lit. Thereby, irregular detection by dust and scattering by smoke can be distinguished and erroneous detection can be prevented.

  Furthermore, when a threshold value smaller than the threshold value for generating an alarm sound is set and the amount of scattered light received by the light receiving element 26 is equal to or greater than the threshold value, the alarm speaker 3 is operated for a certain period to vibrate the housing 21. May be. That is, when the amount of scattered light received by the light receiving element 26 exceeds the threshold value, the alarm speaker 3 is operated for a certain period to vibrate the housing 21. Next, when the light emitting element 25 irradiates light, and the amount of scattered light received by the light receiving element 26 is still more than the threshold value, the alarm speaker 3 is operated again for a certain period to vibrate the housing 21. The vibration of the housing 21 is repeated until the threshold value is below.

[Another embodiment]
In the above embodiment, an example in which one pocket portion 23b is provided has been described, but a plurality of pocket portions 23b may be provided. In this case, in addition to the lowest position, it can be provided at any position where dust is more likely to accumulate from the airflow generated by the shape of the wall portion 23 and the like.

  In the above embodiment, the example in which the pocket portion 23b is formed of the same material as that of the wall portion 23 has been described, but the present invention is not limited to this. For example, the pocket portion 23b can be formed of a member that easily adsorbs dust, such as an adhesive member or a chargeable member. This makes it easier to capture dust.

  In the above embodiment, the configuration in which the pocket portion 23b is provided at the lowermost position when the fire alarm 1 is attached to the wall of the wall portion 23 is illustrated, but is not limited thereto. You may provide the pocket part 23b in the position which becomes lower when the fire alarm 1 is attached to the wall in the wall part 23.

  In the above embodiment, the configuration in which the alarm speaker 3 as the vibration generating unit vibrates the housing 21 is exemplified. However, the vibrator 32 may be provided as a vibration generating unit separately from the alarm speaker 3. Specifically, a vibrator 32 is provided on the upper surface of the substrate 31 on the side of the housing 21 as shown in FIG. 5 to vibrate the housing 21, or the vibrator 32 is interposed between the substrate 31 and the bottom surface portion 21b as shown in FIG. It is conceivable that the housing 21 is vibrated.

  In the above embodiment, the configuration in which the light receiving element 26 is provided above the pocket portion 23b is illustrated, but the light emitting element 25 may be provided above the pocket portion 23b. Further, the light emitting element 25 and the light receiving element 26 may not be provided above the pocket portion 23b.

  In the above-described embodiment, the configuration in which the insect net 24 composed of a wire net or the like is provided separately from the housing 21 is illustrated, but the housing 21 and the insect net may be integrally formed.

  The photoelectric smoke detector according to the present invention can be applied to a smoke sensor that detects smoke, an alarm device that detects smoke and issues an alarm, a measuring device that measures smoke concentration, and the like.

Cross-sectional view of the smoke detector according to this embodiment Schematic diagram of fire alarm according to this embodiment The longitudinal cross-sectional view of the smoke detection part which concerns on this embodiment. The figure which shows the timing of the pulse irradiation of the light based on this embodiment, and the vibration of a housing The figure which shows the relationship between the housing which concerns on another embodiment, and a vibration generation means. The figure which shows the relationship between the housing which concerns on another embodiment, and a vibration generation means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fire alarm 2 Smoke detection part 3 Vibration generating means 21 Housing 23 Wall part 23a Wall part 23b Pocket part 25 Light emitting element (light emission part)
26 Light receiving element (light receiving part)

Claims (6)

A housing having a plurality of walls that allow smoke from outside to flow in and block direct light from outside;
A light emitting unit for irradiating light inside the housing;
A light receiving unit that receives the scattered light of the light caused by smoke flowing into the housing;
In a state where the housing is attached to the wall, the pocket portion is provided so as to open upward in at least a wall portion located on the lower side of the plurality of wall portions, and captures foreign matter that has entered the inside of the housing. When,
A photoelectric smoke detector comprising: vibration generating means for vibrating the housing.   2. The photoelectric smoke detector according to claim 1, wherein the housing includes a light shielding portion that blocks direct light from the light emitting portion toward the light receiving portion, and the pocket portion is provided below the light shielding portion. A control means for controlling the operation of the vibration generating means;
The photoelectric smoke detector according to claim 1 or 2, wherein the control means is configured to operate the vibration generating means for a predetermined period when a preset condition is satisfied.   The photoelectric smoke detector according to claim 3, wherein the control unit determines that the condition is satisfied when a predetermined period elapses after the vibration generating unit is operated.   The photoelectric smoke detector according to claim 3, wherein the control unit determines that the condition is satisfied when a light amount of the scattered light received by the light receiving unit is equal to or greater than a predetermined value.   The photoelectric smoke detector according to claim 1, wherein the vibration generating unit is a speaker integrally attached to the housing.

Images