JP4655070B2 - smoke detector - Google Patents

Description

  The present invention relates to an improvement of a smoke detector having a speaker built in a main body in order to output a fire alarm with a sound or a voice message.

  In recent years, it has been proposed to connect a speaker to a detector as a fire alarm for a smoke detector. It has been proposed (see, for example, Patent Document 1).

  If the speaker is built in the smoke detector body, alarm sounds and voice messages can be emitted downward from high places such as the ceiling, so the sounds and voice messages are easy to spread throughout the residential space and not only fire alarms. Since a plurality of types of notification contents such as a guidance for recovery operation and a battery exhaustion message can be notified by changing the voice message, the convenience is very high.

Furthermore, since these smoke detectors with built-in speakers are connected by wiring with the speakers integrated, installation and wiring work can be performed very easily compared to those of retrofitted speakers.
JP 2005-352932 A

  However, in this type, since the speaker is disposed in the vicinity of the smoke sensing chamber in which the smoke density is measured by the light emitting element and the light receiving element in the main body, air generated by vibration at the time of sound output of the speaker. The flow of air affects the smoke sensitivity in the smoke sensing chamber, creating a situation where it is difficult to detect a fire. Therefore, in smoke detectors for homes that do not have a latch function, the smoke density is reduced by the diffusion of smoke in the smoke detection chamber due to the vibration of the speaker, despite the fact that fire factors continue to occur. There was a problem that the alarm stopped sounding.

  FIG. 4 is a smoke detection time chart showing the above problem. In this case, immediately after the fire occurs, the smoke concentration rises and exceeds the threshold value (10% / m), so it is determined that a fire has occurred. Immediately, the smoke concentration drops and it is determined that the fire is restored.

  Therefore, the problem that the sound of the speaker stops in a short time before the fire factor disappears occurs. In FIG. 4, in order to prevent malfunction, time differences t1 and t2 for determining both fire occurrence and fire recovery are provided.

  The present invention has been proposed in view of such circumstances, and its purpose is to prevent the subsequent flow of air in the smoke sensing chamber due to the vibration of the speaker that occurs during the output of an alarm for sound and voice messages. It is an object of the present invention to provide a smoke detector that does not interfere with normal smoke detection in the smoke detection chamber.

  In order to achieve the above object, a smoke detector according to claim 1 is a smoke detection chamber for measuring smoke density by detecting smoke with a light emitting element and a light receiving element, and a speaker for outputting a sound or voice message. Is installed in the main body, the smoke density measured in the smoke detection chamber is compared with a threshold value, and if the smoke density exceeds the threshold value, it is determined that a fire has occurred, and an alarm or sound message is output from the speaker. On the other hand, when the smoke concentration is lower than the threshold value, in the smoke detector having the control means for controlling to stop the alarm output, the control means determines the threshold value after determining the fire occurrence. The value is changed to a value smaller than the threshold value.

  In the smoke detector according to the second aspect, the space for accommodating the speaker is adjacent to the smoke detection chamber through the partition wall, and the partition wall has a vent hole communicating with each other.

  According to the smoke detector of claim 1, since the threshold value is changed to a value smaller than the threshold value after the control means once determines the occurrence of the fire, the sound or voice message is output. Even if air flows into the smoke sensing chamber due to the vibration of the speaker and the smoke density is reduced, the judgment of fire occurrence can be continued, so that the alarm sound stops even though the actual fire is occurring. I can stop.

  According to the smoke detector of the second aspect, in addition to the effect of the first aspect, the space for accommodating the speaker and the smoke detection chamber communicate with each other through the vent hole provided in the partition wall. As a result, the rear space of the speaker is expanded, sufficient sound pressure is obtained, and the speaker can be vibrated sufficiently.

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

  FIG. 1 is an exploded perspective view showing the structure of a smoke detector as an example of the present invention. In addition, this figure has illustrated the state which reversed the top and bottom with the state installed in the ceiling surface.

  The smoke detector 1 is attached to a ceiling surface or the like downward, and includes a body 2 composed of a disk-like base 2c and a base cover 2b attached to the ceiling surface, and a light emitting element 3a on the surface side. A circuit board 3 on which a light receiving element 3b is mounted and various other electronic components (not shown) are mounted on the back side, a light emitting portion 4a, a light receiving portion 4b, a labyrinth wall 4c having a smoke passage, and the like. Smoke detection chamber 4 that is installed in optical base 4d, a bottomed cylindrical insect-proof cover 5 that covers smoke detection chamber 4, speaker 6 disposed immediately above insect-protection cover 5, and each of the above-mentioned When the member is assembled to the body 2, the bottomed cylindrical protective cover that covers the smoke sensing chamber 4, the insect-proof cover 5, and the speaker 6 protruding from the opening 2 a of the body 2 and is locked to the opening 2 a of the body 2. 7.

  The electronic components mounted on the back surface of the circuit board 3 include a CPU, a ROM (not shown) and the like, and a CPU and a program written in the ROM are used for smoke concentration sampling and fire occurrence described later. The control means 10 is configured to execute processing operations such as determination of fire recovery (recovery from a fire occurrence state to a normal state).

  The top surface 5b of the insect-proof cover 5 acts as a partition wall that partitions the speaker housing space and the smoke sensing chamber 4, and a speaker installation base 5c is provided at the center of the partition wall 5b. Further, the partition wall 5b is provided with a vent hole 5a communicating with the smoke sensing chamber 4 so that sufficient sound pressure can be obtained when the speaker 6 vibrates sufficiently. A large number of sound holes 7 a are formed in the top surface of the protective cover 7 that covers the sound output surface of the speaker 6.

  The base 2c is screwed to the ceiling surface with the circuit board 3, the smoke detection chamber 4, the insect-proof cover 5, the speaker 6 and the protective cover 7 attached, and the base cover 2b is put on the top to cover the smoke detection chamber 4 The smoke detector 1 is attached and fixed to the ceiling surface by locking the base cover 2b to the base 2c with the protective cover 7 housing the insect-proof cover 5 and the speaker 6 projecting from the opening 2a. .

  When the smoke detector 1 is assembled in this way, the light emitting element 3a and the light receiving element 3b are accommodated in the light emitting part 4a and the light receiving part 4b of the smoke sensing chamber 4, respectively. A region (not shown) is formed and the light emitting element 3a and the light receiving element 3b interact to detect smoke flowing into the smoke sensitive region.

  FIG. 2 is a timing chart showing the basic operation of fire occurrence / recovery determination by the smoke detector 1.

  The smoke detector 1 is configured such that when a real fire occurs and the smoke density gradually increases and a predetermined threshold value is exceeded, it is determined that a fire has occurred, and an alarm is output from the speaker with a voice message (or sound). However, once it is determined that a fire has occurred, the threshold value is lowered to a predetermined value, and the measured smoke concentration is compared with the threshold value at which the measured value is reduced. Judgment is being made.

  In the case of the illustrated example, after the fire occurrence is determined (determined), air diffuses the smoke in the smoke detection chamber 4 due to the sound of the speaker 6 even though an actual fire is occurring, and the smoke concentration gradually increases. Although it has decreased, the threshold value is set to a small value, so fire recovery is not judged during an actual fire, and fire restoration judgment is made when it falls below the lower threshold. . Here, the lower threshold value is set in advance assuming a threshold value at the time of actual fire recovery.

  As described above, since the threshold value is changed to a small value after the occurrence of the fire is determined, even if the smoke flows due to the vibration of the speaker 6 and the smoke concentration is reduced, the fire is generated. Therefore, it is possible to prevent the alarm of the speaker 6 from being stopped even when an actual fire is occurring.

  As in the structure of this example (see FIG. 1), in the case where the rear space of the speaker 6 is expanded to the smoke detection chamber 4 by the vent hole 5a provided in the partition wall 5, sufficient sound pressure can be obtained by the space. Instead, the vibration of the speaker 6 affects the flow of air in the smoke sensing chamber 4 and lowers the smoke density. According to the configuration of switching between the two threshold values of the present invention, such a structure is provided. Especially effective.

  The unit of smoke density is expressed in% / m, which represents the fading rate per meter. In the example shown in the figure, the threshold for determining the occurrence of fire (normal threshold) is 10% / m, and the fire is confirmed. The later threshold value (low threshold value) is 8% / m. The normal threshold and low threshold for fire judgment are set to appropriate values that can quickly determine the occurrence of a fire after an actual fire has occurred, and that can determine the fire recovery after the actual fire has recovered. Needless to say.

  In order to prevent smoke detection malfunctions, time differences t1 and t2 are provided for both fire occurrence and fire recovery from the time when the threshold value is first exceeded or below the threshold value to be determined. These time differences t1 and t2 are measured depending on whether the smoke density sampled at a predetermined period exceeds the threshold value N times or falls continuously N times. That is, the time differences t1 and t2 are expressed by a sampling period (for example, 4 seconds) × N 2. N times may be set once, and t1 and t2 may be different values.

  FIG. 3 is a flowchart showing a fire occurrence / recovery operation of the smoke detector 1.

  The operation procedure shown in this flowchart is executed by the control unit 10, that is, the CPU mounted on the circuit board 3, in cooperation with software (program). Note that the description of the flowchart of FIG. 3 is performed along the time-series flow shown in the time chart of FIG.

  The control means 10 is activated, for example, at a cycle of 4 seconds by the clock of the CPU, and executes smoke density sampling every 4 seconds and fire generation and recovery processes based on the smoke density (steps 101 to 106). . Then, when an actual fire is generated by this operation procedure, the determination that the sampled smoke density is equal to or greater than the threshold value is repeated N times continuously (steps 102 to 104). Output of a voice message is started (step 105), and the threshold value is changed to a small value (step 106).

  After that, the sampled smoke concentration is compared with the threshold value that has become low, and during the occurrence of an actual fire, the fire determination state is maintained (N in Steps 101 to 103), but the actual fire is restored, When the determination that the smoke density is less than the threshold value is repeated N times in succession, a fire recovery determination is made (steps 102, 107, 108), and the output of the voice message from the speaker 6 is stopped (step 109). The threshold value is returned to the original value (step 110).

  Note that the flow in this figure shows the process of holding (latching) the occurrence of a fire and fire recovery at the determination of the Nth consecutive time. However, after the Nth consecutive time, the occurrence of a fire and the recovery of the fire (whether the speaker is ringing) ) May be determined.

  In addition, since the smoke detector of the present invention is configured to determine the occurrence and recovery of a fire using two thresholds, the occurrence of a fire with the same determination logic (step 102) as in the example of FIG. Instead of determining whether or not recovery is possible, determination may be made using determination logic for occurrence and recovery separately.

  Since the smoke detector of the present invention uses two threshold values to determine the occurrence and recovery of a fire, as shown in the figure, the determination of the occurrence of a fire is greater than or equal to the threshold (smoke concentration ≧ threshold ), It is not necessary to limit the judgment of fire restoration to a reverse judgment logic such as less than a threshold value (smoke concentration <threshold value). The determination of fire restoration may be made by the determination of (smoke density ≦ (low) threshold).

  Further, in the smoke detector of the present invention, as shown in FIG. 2, a low threshold value indicates a fire occurrence state (from the fire confirmation to the fire recovery confirmation in the figure). In the processing, it is possible to determine whether or not a fire has occurred by checking which value the threshold value is. That is, the threshold value can be used instead of the fire occurrence state flag.

It is the disassembled perspective view which showed the structure of the smoke detector which is an example of this invention. It is the timing chart which showed the basic operation of the fire occurrence / recovery judgment with the same smoke detector. It is the flowchart which showed the fire generation / restoration operation | movement of the smoke detector. It is the timing chart which showed the timing of fire occurrence / recovery of the conventional smoke detector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Smoke detector 10 Control means 2 Body 3 Circuit board 3a Light emitting element 3b Light receiving element 4 Smoke detection chamber 4a Light emitting part 4b Light receiving part 5 Insect-proof cover 5a Vent hole 5b Partition wall 6 Speaker 7 Protective cover

Claims (2)

A smoke detection chamber that detects smoke with a light emitting element and a light receiving element and measures the smoke concentration and a speaker that outputs a sound or voice message are installed in the main body, and the smoke concentration measured in the smoke detection chamber is the threshold. When the smoke concentration exceeds the threshold value, it is determined that a fire has occurred, and a warning or sound message is output from the speaker, while the smoke concentration falls below the threshold value. Sometimes, in a smoke detector equipped with a control means for performing control to stop the output of the alarm,
The smoke detector according to claim 1, wherein the control means changes the threshold value to a value smaller than the threshold value after determining the occurrence of a fire. In claim 1,
A space in which the speaker is accommodated is adjacent to the smoke detection chamber via a partition wall, and a smoke sensor is provided with a vent hole communicating with the partition wall.

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