JP3321054B2 - Fire alarm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fire alarm device which senses a physical quantity that changes due to a fire with a predetermined sensitivity to detect whether or not a fire has occurred, and issues a sound alarm when a fire is detected.

[0002]

2. Description of the Related Art A conventional simple fire alarm device is configured such that when a fire detector incorporated in the alarm device detects a fire, the fire detector detects the fire.
Emits a warning sound to alert you of a fire.

[0003]

The alarm sound has a very high volume in consideration of the alarm effect, has a sudden sound, and has an exciting tone. For this reason, there has been a problem that the residents may be surprised, feel a physical or physical shock or discomfort, and may panic in some cases. In addition, when the fire detection unit is not a fire, there is a possibility that the fire may be detected as a fire also by smoke or heat generated by cigarette smoke or cooking.
In such a case, it is sufficient that the resident can be alerted, and a loud alarm is unpleasant and unnecessary.

[0004] The present invention eliminates the shock and discomfort of residents caused by sudden loud noises,
It is another object of the present invention to provide a fire alarm device that can issue a warning to the extent that the user is warned first even when a fire is sensed by cigarettes or cooking.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises a fire detecting means for detecting a physical quantity changed by a fire with a predetermined sensitivity and detecting whether or not a fire has occurred; When the fire detection unit detects a fire, the fire alarm unit includes a fire alarm unit that issues a fire alarm and notifies the occurrence of a fire, wherein the fire alarm unit can issue a preliminary alarm for a certain period of time. A sensitivity adjusting means for lowering the sensitivity of the fire detecting means by being operated from the outside when the preliminary alarm is sounded, wherein the fire notifying means first detects the fire when the fire detecting means detects a fire. If an alarm is issued and the sensitivity adjusting means is operated during the sounding of the preliminary alarm, the fire alarm means stops the sounding of the preliminary alarm and the fire detecting means emits the predetermined sound. When the fire detection means detects a fire at a lower sensitivity and the fire detection means detects a fire, the fire notification means emits a fire alarm, and the predetermined time after the start of sounding of the preliminary alarm. In the meantime, when the fire detection means is still detecting the fire and the sensitivity adjustment means is not operated, after the lapse of the predetermined time, the fire notification means emits a fire alarm. .

According to the fire alarm device of the first aspect,
When the fire detection means detects a fire, first, the fire notification means emits a preliminary alarm. When the resident notices the preliminary alarm and operates the sensitivity adjusting means, the fire notification means stops the sounding of the preliminary alarm, and the fire detecting means detects whether or not there is a fire with the sensitivity lowered. If a fire is detected even when the sensitivity is lowered, the fire alarm emits a fire alarm. Therefore, even if the fire detection means detects a fire, the fire alarm does not suddenly sound, but instead, the preliminary alarm sounds first, and then the fire alarm sounds. This prevents shock and discomfort experienced by residents and does not panic.

In addition, even when the fire detecting means detects a fire due to a temporary and local pseudo-fire situation such as tobacco, cooking, etc., a preliminary alarm sounds first, so that the residents are gently alerted. And residents can calm down from cigarettes, cooking and the like so that a full-scale fire does not occur. Then, at that time, if the resident operates the sensitivity adjusting means, the sensitivity of the fire detecting means is reduced, so that the fire alarm device does not detect the fire in the simulated fire situation as described above, As long as the fire does not spread, no fire alarm will be issued and no unnecessary alarm will be issued.

[0008] In addition, even when the fire detection means keeps detecting the fire and the sensitivity adjusting means is not operated, the fire alarm is sounded after the preliminary alarm sounds for a certain period of time. Even if you do not notice the alarm, you can know the occurrence of the fire by the fire alarm.

[0009] Here, the preliminary alarm and the fire alarm are such that the preliminary alarm informs the possibility of a fire and warns the user. The fire alarm always informs the residents of the occurrence of the fire in comparison with the preliminary alarm. What is necessary is just to have a large alarm effect. For example, the preliminary alarm is a sound having a moderate volume and a fixed interval, an intermittent sound such as "Pee, Pee",
The fire alarm may be a continuous sound "Pee" having a higher volume, the preliminary alarm may be a recorded or an announcement made by an electrically synthesized voice, and the fire alarm may be a siren, or a preliminary alarm. Is a low frequency sound,
The fire alarm may be a high frequency sound.

[0010] The physical quantity that changes due to a fire is
It is a physical value related to events such as heat, smoke, and flame caused by the occurrence of a fire. A physical quantity corresponding to heat is temperature, and if it is smoke, its concentration. The fire detecting means has an element for sensing these physical quantities, for example, a thermistor, a light emitting diode and a photodiode.

The sensitivity adjusting means is a switch or the like having a structure which can be operated from outside by a resident. As a fire alarm device, the sensitivity of the fire detecting means is lowered by being operated. In other words, from the standpoint of the user of the fire alarm device, it can be said that the fire alarm device is a confirmation means for confirming whether or not a fire has occurred.

According to a second aspect of the present invention, in the fire alarm device according to the first aspect, the preliminary alarm has a lower volume than the fire alarm.

[0013] According to the fire alarm device of the second aspect,
Even if the fire detection means detects a fire, the fire alarm does not suddenly sound, but first, a low-volume spare alarm sounds, and then the higher-volume fire alarm sounds, The sounding of the fire alarm can prevent the residents from being shocked or uncomfortable and do not panic. In addition, when a fire is detected due to a temporary and local simulated fire situation such as tobacco or cooking, a low volume preliminary alarm sounds first, so that residents can be gently alerted. It is possible for residents to calm down from cigarettes, dishes and the like so that a full-scale fire does not occur.

According to a third aspect of the present invention, in the fire alarm device according to the first or second aspect, the preliminary alarm gradually changes so as to increase the alarm effect.

According to the fire alarm device of the third aspect,
The preliminary alarm changes gradually so that the alarm effect increases. More specifically, for example, there is a case where the volume of the preliminary alarm gradually increases or the frequency gradually increases. Alternatively, there may be a case where the sound starts with an intermittent sound having a predetermined interval and the interval gradually decreases. Therefore, according to the third aspect of the present invention, it is possible to more calmly call attention to the resident, and it is possible to prevent shock and discomfort experienced by the resident.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. FIG.
FIG. 1 is a block diagram showing a configuration of a fire alarm device 10 according to an embodiment of the present invention.

The fire alarm device 10 shown in FIG. 1 is a simplified fire alarm device having a built-in power supply and fire detection function.
For example, it is disposed in a general house or the like, and mainly includes a control circuit 1, a fire detection circuit 2, an audio device circuit 3, a voltage detection circuit 4, a battery E, a confirmation switch SW1, a reset switch SW2, and the like.

The control circuit 1 is connected to the fire detection circuit 2, the acoustic device circuit 3, the voltage detection circuit 4, the battery E, the confirmation switch SW1, and the reset switch SW2. The signal input from the circuit 4, the confirmation switch SW1, and the reset switch SW
2 is turned on, the fire detection circuit 2,
Signals are output to the audio device circuit 3 and the like to control their operations. When the power is turned on, the control circuit 1
An LED control signal is output to the fire detection circuit 2.
In addition, the control circuit 1 outputs a fire alarm signal as a result of the fire monitoring performed by the fire detection circuit 2 according to the LED control signal. Output to the audio device circuit 3. When the confirmation switch SW1 (sensitivity adjusting means) is turned on, the control circuit 1 stops the operation of the first timer and the output of the preliminary alarm signal, and outputs a threshold change signal to the fire detection circuit 2. . In addition, the control circuit 1 outputs a voltage drop warning signal to the audio device circuit 3 according to the voltage drop signal output by the voltage detection circuit 4.

The control circuit 1 further includes a first timer and a second timer (not shown). In the normal fire monitoring state, the control circuit 1 sets the first timer when a fire output signal is input from the fire detection circuit 2, and outputs a threshold change signal when the confirmation switch SW1 is turned on after the first timer is set. The signal is output to the fire detection circuit 2 and a second timer is set.

The control circuit 1 includes a reset switch S
When W2 is turned on, the output of the LED control signal and the fire alarm signal is stopped, and the state of the fire alarm device 10 is returned to the initial setting state. Further, the control circuit 1 also returns the state of the fire alarm device 10 to the initial setting state when the second timer times out.

The fire detection circuit 2 which is fire detection means includes:
A smoke density threshold for determining whether or not a fire has occurred is set. On the other hand, the fire detection circuit 2 has a smoke detection unit 2a including a light emitting diode (LED) as a light emitting element and a photodiode as a light receiving element. Have. Fire detection circuit 2
, Based on the LED control signal output from the control circuit 1, switches the LED of the smoke detector 2a at intervals of several seconds from 100 to 15
The pulse emission is performed at a width of 0 microsecond, and the smoke density is calculated based on the electromotive force generated in the photodiode, which differs depending on the smoke density. In response, a fire output signal is output. Further, when a threshold change signal is input from the control circuit 1, the fire detection circuit 2 changes the stored threshold to a higher value. That is, the sensitivity of the fire alarm device 10 is reduced when the resident operates the confirmation switch SW1.

The acoustic device circuit 3 serving as a fire alarm means has, for example, a buzzer and the like, and sounds an alarm in response to each of a fire alarm signal, a preliminary alarm signal, and a voltage drop alarm signal output from the control circuit 1. Emits. When these signals are no longer input, the generation of each alarm sound is stopped. When the preliminary alarm signal is input, the audio device circuit 3 emits a preliminary alarm sound (preliminary alarm) having a predetermined interval and an appropriate volume, such as "Pi, Pi ...". Also, when a fire alarm signal is input, a fire alarm sound (fire alarm) that is a continuous sound such as "P" having a larger volume than the preliminary alarm sound.
Emits. When the low voltage alarm signal is input,
"Beep ... beep ..." emits an intermittent battery warning once every several tens of seconds.

The battery E is mounted in a battery box (not shown) of the fire alarm device 10 and supplies a power supply voltage to each circuit. The voltage detection circuit 4 is connected to both ends of the battery E, monitors the voltage of the battery E, and outputs a voltage drop signal to the control circuit 1 when the voltage of the battery E falls below a predetermined voltage.

Confirmation switch SW1 as sensitivity adjustment means
Is an externally operable switch connected to the control circuit 1, and can be operated, for example, by pressing a push button switch provided on an outer case (not shown) of the fire alarm device 10. When the confirmation switch SW1 is operated in a state where the preliminary alarm sound is sounded, the confirmation switch SW1 is turned on.

The reset switch SW2 is a switch which can be operated from the outside. For example, the reset switch SW2 can be operated by pressing a push button switch provided on an outer case (not shown) of the fire alarm device 10. And
If the fire alarm sounds and the resident decides to stop the fire alarm due to a false alarm or the like, the operation is turned on when operated.

The operation of the fire alarm device 10 having the above configuration will be described with reference to FIG. FIG. 2 shows a fire alarm device 1
It is a timing chart of 0, and three patterns are given as an example. In each of these patterns (I) to (III), the horizontal direction indicates time. In the fire situation at the bottom, two set thresholds are indicated by dotted lines together with an assumed change in smoke density. Fire alarm device 10
Sets the lower threshold in FIG. 2 in the normal fire monitoring state.

Pattern (I) is an operation when a fire actually occurs and the resident does not operate the confirmation switch SW1. When the power of the fire alarm device 10 is turned on, the control circuit 1 outputs an LED control signal to the fire detection circuit 2, and in response to this, the fire detection circuit 2 enters a fire monitoring state. In a normal fire monitoring state, a fire is detected with a low threshold, that is, with high sensitivity.

When a fire occurs at a certain point in time and the fire situation spreads over time and exceeds a threshold value (point A in FIG. 2), the fire detection circuit 2 determines that a fire has occurred and outputs a fire output signal to the control circuit. Output for 1 Control circuit 1
Outputs a preliminary alarm signal to the audio device circuit 3 based on the fire output signal input from the fire detection circuit 2,
On the other hand, time measurement by the first timer is started. When the preliminary alarm signal is input from the control circuit 1, the audio device circuit 3
A preliminary alarm sound is emitted at a predetermined interval and volume as "Pi, Pi ...".

If the confirmation switch SW1 is not operated, and
The state where the fire situation exceeds the threshold continues, and the fire detection circuit 2
When the first timer times out in a state in which the fire is still detected, the control circuit 1 outputs a fire alarm signal to the audio device circuit 3 (at the point A ′). Sound device circuit 3
When a fire alarm signal is input from the control circuit 1, the loud fire alarm sounds as a continuous sound "Pee". When the reset switch SW2 is operated by the resident while the fire alarm sound is sounding (at the time “A”), the fire alarm device 10 returns to the initial setting state.

In this case, the reset switch SW2
Is not operated, the fire detection circuit 2 continues to output a fire output signal and the control circuit 1 outputs a fire alarm signal as long as the fire condition exceeds the threshold value, whereby the sound device circuit 3 is output.
Keeps sounding fire alarm.

In the pattern (II), a situation similar to a fire occurs temporarily and locally due to cooking, cigarettes, etc., and the preliminary alarm sound of the fire alarm device 10 sounds, and the resident responds to the preliminary alarm sound. This is an operation when the confirmation switch SW1 is operated. Similarly to the pattern (I), in a normal fire monitoring state, a fire is detected with a low threshold, that is, with high sensitivity.

At a certain point in time, when the smoke density around the fire alarm device 10 rises due to cooking, cigarettes, etc., and exceeds a threshold value (point B), the fire detection circuit 2 detects a fire and controls the fire output signal. Output to circuit 1. Control circuit 1
Outputs a preliminary alarm signal to the audio device circuit 3 based on the fire output signal input from the fire detection circuit 2,
On the other hand, time measurement by the first timer is started. When the preliminary alarm signal is input from the control circuit 1, the audio device circuit 3
A preliminary alarm sound is emitted at a predetermined interval and volume as "Pi, Pi ...".

When the confirmation switch SW1 is operated while the preliminary alarm sound is sounding, the control circuit 1 stops the time counting by the first timer and the output of the preliminary alarm signal, and the smoke for the fire detection is stopped. A threshold change signal is output to the fire detection circuit 2 so as to reset the density threshold higher. At the same time, the control circuit 1 starts counting time by the second timer (time point B ′). When the threshold change signal is input from the control circuit 1, the fire detection circuit 1 sets the smoke density threshold high, that is, keeps monitoring the fire with low sensitivity. When the second timer times out without the fire condition spreading over time and without exceeding the reset threshold value, the fire alarm device 10 returns to the initial state.

In the pattern (II), after the preliminary alarm sounds, if the confirmation switch SW1 is not operated and the surrounding situation falls below the threshold before the first timer expires, the first switch is activated at that time. The timer resets and returns to normal fire monitoring.

In pattern (III), a fire actually occurred,
This is an operation when the resident operates the confirmation switch SW1 in response to the preliminary alarm sound. As in the patterns (I) and (II), in a normal fire monitoring state, a fire is detected with a low threshold, that is, with high sensitivity.

At a certain time, a fire occurs, and the fire situation spreads over time. If the fire condition exceeds a threshold (time C), the fire detection circuit 2 determines that a fire has occurred and sends a fire output signal to the control circuit 1. Output. The control circuit 1 outputs a preliminary alarm signal to the audio device circuit 3 based on the fire output signal input from the fire detection circuit 2, and starts timing by the first timer. When the preliminary alarm signal is input from the control circuit 1, the audio device circuit 3 emits a preliminary alarm sound at a predetermined interval and volume, such as "Pi, Pi ...".

When the confirmation switch SW1 is operated by the resident while the preliminary alarm sound is sounding, the control circuit 1
Outputs a threshold change signal to the fire detection circuit 2 so as to stop timekeeping by the first timer and output of the preliminary alarm signal and reset the threshold value of the smoke density to a higher value. Also,
At the same time, the control circuit 1 starts counting time by the second timer (at time C ′). When the threshold change signal is input from the control circuit 1, the fire detection circuit 2 sets a high smoke density threshold, that is, continues monitoring with low sensitivity whether a fire has occurred.

When the fire situation spreads further and the threshold value is exceeded even at a low sensitivity (at time "C"), the fire detection circuit 2 determines that there is a fire and outputs a fire detection signal to the control circuit 1. The circuit 1 outputs a fire alarm signal to the audio device circuit 3 based on the fire detection signal input from the fire detection circuit 2. The audio device circuit 3 outputs the fire alarm signal according to the input fire alarm signal. The fire alarm device 10 emits the fire alarm sound as long as the fire condition exceeds the threshold value or the reset switch SW2 is not operated as in the pattern (I).

Next, a processing operation relating to fire detection and sounding of an alarm sound performed by the control circuit 1 and the fire detection circuit 2 will be described with reference to the flowchart of FIG. When the power of the fire alarm device 10 is turned on, the processing operation is started. First, in step S1, initial settings such as a first timer, a second timer, and a threshold (sensitivity) are performed. Next, the process proceeds to step S2, where the control circuit 1 outputs an LED control signal to the fire detection circuit 2, and the fire detection circuit 2 enters a fire monitoring state. In the state of fire monitoring,
It is determined whether or not the second timer has been set (step S3). If the second timer has not been set, the process proceeds to step S4. In step S4, when the fire detection circuit 2 determines that a fire has occurred as a result of the fire monitoring, the process proceeds to step S5.

In step S4, if the fire detection circuit 2 determines that the situation around the fire alarm device 10 is below the threshold, the process returns to step S2. That is, the LED output from the control circuit 1 in step 2
Unless a fire is detected by the fire detection circuit 2 according to the control signal, the processing of steps S2, S3, and S4 is repeated.

In step S5, the control circuit 1 sets a first timer, and then proceeds to step 6. In step S6, the control circuit 1 outputs a preliminary alarm signal to the audio device circuit 3, whereby a preliminary alarm sound is emitted. The process proceeds to step S7 with the preliminary alarm sounding, and the fire alarm device 10 enters the fire monitoring state. In step S8, the fire detection circuit 2 determines whether or not there is a fire. When the fire detection circuit 2 determines that a fire has occurred, the process proceeds to step S9, and the control circuit 1 determines whether or not the first timer has expired. If the time is not up, the process proceeds to step S14, and the confirmation switch SW1
Is determined, and if the confirmation switch SW1 is operated, the process proceeds to step S15.

In step S15, the control circuit 1 outputs a threshold change signal to the fire detection circuit 2, and the fire detection circuit 2 changes and sets the threshold accordingly. Further, the control circuit 1 sets a second timer, and starts time measurement by the second timer.

On the other hand, if it is determined in step S14 that the confirmation switch SW1 has not been operated, the process returns to step S6. Until the first timer times out, if the fire condition does not fall below the threshold and the confirmation switch SW1 is not operated, steps S6, S7,
Steps S9 and S14 are repeated. Further, in step S8, when the surrounding situation is lower than the threshold value and the fire detection circuit 2 determines that it is not a fire, the process proceeds to step S18,
The first timer is reset, and the process returns to step S2.

After step S15, the process returns to step S2. Next, in step S3, it is determined whether or not the second timer has been set. If the second timer has been set, the process proceeds to step S16. . Step S1
In 6, it is determined whether or not the second timer has not expired. If the result of this determination is that the second timer has not expired, the flow proceeds to step S17. Step S1
In step 7, based on the result of the fire monitoring in step S2, a process of determining whether or not a fire has occurred is performed. If it is determined that a fire has occurred, the process proceeds to step S10. On the other hand, if it is determined in step S17 that the fire is not a fire, the process returns to step S2. If the fire condition does not exceed the reset high threshold, steps S2, S3, S16, and S16 are performed until the second timer times out. S17 is repeated.

In step S10, the control circuit 1 performs a process of outputting a fire alarm signal to the audio device circuit 3,
Thereby, a fire alarm sounds. Next, step S
11 and the control circuit 1 resets the reset switch SW2
Is determined to be ON or OFF, and if it is determined that the reset switch SW2 is OFF, the process proceeds to step S12, and the control circuit 1 again sends an LED to the fire detection circuit 2.
A process of outputting a control signal is performed, and in response to this, the fire detection circuit 2 performs fire monitoring. In step S13, the fire detection circuit 2 is detected by the fire monitoring in step S12.
Performs a process of determining whether or not it is a fire. If it is determined that a fire has occurred, the process returns to step S10, and a fire alarm sounds. Therefore, as long as it is determined in step S13 that a fire has occurred, steps S10, S11, S1 are performed regardless of the expiration of the second timer.
2. The process of S13 is repeated, and the fire alarm device 10 continues to emit a fire alarm sound. If it is determined in step S13 that it is not a fire, the process returns to step S2.

The control circuit 1 and the fire detection circuit 2
If it is determined in step 16 that the second timer has expired, the process returns to step S1.

On the other hand, if it is determined in step S11 that the reset switch SW2 is ON, the process returns to step S1.

As can be seen from FIG. 3, after the fire detection circuit 2 resets the threshold value for fire detection, it always returns to the initial state of step S1 through steps S16 and S11. Return to value.

According to the above fire alarm device 10, when the fire detection circuit 2 detects a fire, first, the sound device circuit 3 emits a preliminary alarm sound. When the resident notices the preliminary alarm sound and operates the confirmation switch SW1, the sound device circuit 3 stops the sounding of the preliminary alarm sound, while the fire detection circuit 2 detects whether or not there is a fire with the sensitivity lowered. I do. When a fire is detected even when the sensitivity is lowered, the acoustic device circuit 3 emits a fire alarm sound. Therefore, even if the fire detection circuit 2 detects a fire, the fire alarm sound does not suddenly sound, but first, a lower volume, preliminary alarm sound sounds, and then the fire alarm sound sounds. Therefore, suddenly sounding a loud fire alarm can prevent the shock and discomfort experienced by residents, and does not cause panic.

Also, when the fire detection circuit 2 detects a fire due to a temporary and local pseudo-fire situation such as tobacco or cooking, a preliminary alarm sounds first, so that the residents are calm. Residents can calm down to prevent a full-fledged fire from smoking or cooking. Then, at this time, if the resident operates the confirmation switch SW1, the sensitivity of the fire detection circuit 2 decreases, so that the fire detection circuit 2 does not detect the fire in the simulated fire situation as described above. Unless a typical fire spreads, no fire alarm sound is generated, so that an unnecessary loud alarm is not issued.

When a fire occurs, the confirmation switch SW1
When the resident does not operate, even if the resident does not notice the preliminary alarm, the fire alarm sounds after the preliminary alarm sounds for a certain period of time (after the first timer expires). You can know the occurrence of fire by sound.

In the above-described embodiment, the type in which a fire is detected by smoke is described. However, the present invention is not limited to this. It may be.

The interval between the sounds of "Pi, Pi" of the preliminary alarm sound may be gradually shortened. The preliminary alarm sound may be a human voice. In this case, the human voice may be a recorded human voice or an electrically synthesized voice. The preliminary alarm sound may have a constant volume, but may be set so that the volume gradually increases. Further, the preliminary alarm sound may be a sound having a lower frequency as compared with the fire alarm sound. In this case, the auxiliary alarm sound may have a constant frequency, but the frequency is set so that the frequency gradually increases. Is also good. In addition, the fire alarm sound is not limited to the above-described embodiment, and may be a dissonant sound or a fire announcement by a human voice.

In the above embodiment, the confirmation switch SW1 and the reset switch SW2 are operated separately. However, one push button switch is provided on the outer case (not shown) of the fire alarm device. The push button switch may be configured to exhibit the functions of the above two switches. In this case, for example, the two functions are selectively used depending on the operation time of the switch, and if the operation is performed within a predetermined time (for example, 5 seconds),
If the confirmation switch SW1 is turned on and the operation is performed for a longer time, the reset switch SW2 may be turned on.

[0055]

According to the first aspect of the present invention, even if a fire is detected, a fire alarm does not suddenly sound, but a preliminary alarm sounds first, and then a fire alarm sounds. Therefore, suddenly, the fire alarm sounds to prevent the residents from being shocked or discomforted, and does not cause panic. In addition, when a fire is detected due to a temporary and local simulated fire condition such as tobacco or cooking, a preliminary alarm sounds first, so that residents can be gently alerted. Can calm down and prevent fire from cigarettes, cooking and the like. Then, at that time, if the resident operates the sensitivity adjusting means, the sensitivity of the fire detecting means is reduced, so that the fire alarm device does not detect the fire in the simulated fire situation as described above, Unless the fire spreads, the fire alarm will not sound, so no unnecessary alarm will be issued. In addition, even if the fire is still detected after the preliminary alarm is sounded and the sensitivity adjustment means is not operated, the fire alarm is sounded after the preliminary alarm sounds for a certain period of time. Even if you do not notice the fire alarm, you can know the occurrence of the fire.

According to the second aspect of the present invention, the fire alarm does not suddenly sound even if the fire detecting means detects a fire. Since the louder fire alarm sounds, the audible fire alarm can prevent the occupants from being shocked or discomforted by the sounding of the fire alarm, without panic. Also, when a fire is detected due to a temporary and local pseudo-fire situation such as tobacco or cooking,
First, since a low volume preliminary alarm sounds, the resident can be gently alerted to the resident, and the resident can calm down to prevent a full-scale fire from being caused by cigarettes or cooking.

According to the invention described in claim 3, according to claim 1
In addition to the effect of the second aspect of the invention, the preliminary alarm changes gradually so as to increase the alarm effect, so that it is possible to further alert the resident gently, Discomfort can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a fire alarm device as an example of the present invention.

FIG. 2 is a timing chart showing the operation of the fire alarm device of FIG.

FIG. 3 is a flowchart showing a processing operation of the fire alarm device of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control circuit 2 Fire detection circuit (fire detection means) 2a Smoke detection part 3 Sound device circuit (fire notification means) 4 Voltage detection circuit 10 Fire alarm device E Battery SW1 Confirmation switch (sensitivity adjustment means) SW2 Reset switch

Continuation of the front page (56) References JP-A-63-56797 (JP, A) JP-A-54-155496 (JP, U) JP-A-60-57894 (JP, U) JP-A-5-30990 (JP, U) , U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G08B 17/00-31/00

Claims (3)

(57) [Claims] 1. A fire detection means for detecting a physical quantity changed by a fire with a predetermined sensitivity to detect whether or not a fire has occurred, and when the fire detection means detects a fire, a fire alarm is issued to notify the occurrence of the fire. A fire alarm device comprising: a fire alarm device that emits a preliminary alarm for a certain period of time; and when the preliminary alarm sounds, the fire alarm device is operated from outside. When the fire detection means detects a fire, the fire alarm means first issues the preliminary alarm, and operates the sensitivity adjustment means when the preliminary alarm sounds. The fire alarming means stops sounding the preliminary alarm, and the fire detecting means detects whether or not a fire has occurred with a sensitivity lower than the predetermined sensitivity. Upon detecting a fire, the fire notification means emits a fire alarm, and the fire detection means remains in the state of detecting the fire for the predetermined time after the preliminary alarm starts sounding, and The fire alarm device, wherein when the sensitivity adjustment unit is not operated, the fire notification unit issues a fire alarm after the lapse of the predetermined time. 2. The fire alarm device according to claim 1, wherein the volume of the preliminary alarm is lower than that of the fire alarm. 3. The fire alarm device according to claim 1, wherein the preliminary alarm changes gradually so as to increase the alarm effect.