JP5963181B2 - Gas alarm - Google Patents

Description

  The present invention relates to a gas alarm device, and in particular, a gas sensor for detecting a gas concentration of a detection target gas, and an alarm generating means for generating an alarm when the gas concentration detected by the gas sensor exceeds an alarm value, It is related with the gas alarm device provided with.

  Examples of the gas alarm device described above include a gas leak alarm device that generates an alarm by detecting the gas concentrations of LP gas and city gas (detection target gas), and carbon monoxide gas (detection target gas) that is generated during incomplete combustion. Incomplete combustion alarms that detect gas concentrations and generate alarms have been proposed. The gas leak alarm device is provided to start an alarm when the gas concentration of LP gas or city gas is equal to or higher than an alarm value, and then stop when the alarm gas value is equal to or lower than the alarm value. Note that the alarm value of the gas leak alarm is set to a value equal to or less than 1/4 LEL (explosive lower limit). Similarly, the incomplete combustion alarm device is also provided to start an alarm when the gas concentration of the carbon monoxide gas exceeds the alarm value and then stop when the gas concentration becomes the alarm value or less. ing.

  When the LP gas or city gas leaks and the gas leak alarm generates an alarm, guidance is given to open the doors and windows, ventilate, and close the gas and instrument plugs. In addition, when carbon monoxide gas is generated and the incomplete combustion alarm generates an alarm, guidance is given to open the doors and windows to ventilate and stop the use of gas appliances. However, even if ventilation is performed, the gas concentrations of LP gas, city gas, and carbon monoxide gas do not immediately fall below the alarm value, and it takes some time to ventilate the gas concentration below the alarm value. There is a need to do. For this reason, even after ventilating, an alarm is generated for a while from the gas alarm. As described above, if the alarm from the gas alarm does not stop immediately even after ventilation, it is unclear whether the ventilation itself is effective, and there is a problem that the user is raised anxious. In some cases, the gas alarm is returned from the user because the alarm does not stop.

  Similarly, if a gas alarm is blown to the gas alarm device during inspection, or if a spray of insecticide or other spray is accidentally sprayed to the gas alarm device, and the gas alarm device malfunctions, an alarm is generated. The alarm is not stopped immediately, and there is a problem that the user is similarly anxious. By the way, most recent gas leak alarms for city gas are equipped with activated carbon filters for preventing malfunction. The gas leak alarm equipped with this activated carbon filter, after the alarm is generated, even if ventilation is performed, the gas adsorbed on the activated carbon filter is gradually released, so the gas concentration decreases slowly, and once the alarm occurs, the alarm stops. Tends to be slow, which is a particular problem.

  Therefore, for example, a gas alarm as described in Patent Document 1 is known. In the inspection mode, this gas alarm is forcibly stopped when the detected gas concentration is continuously lower than the previous detection value twice after the alarm is generated. However, in the normal mode as well, when the gas alarm is operated so as to forcibly stop the alarm when the gas concentration is continuously lower than the previous detection value twice after the alarm is generated, The alarm stops even though is not below the alarm value. For this reason, there exists a possibility that ventilation may be stopped according to an alarm stop in the state where the user is not performing sufficient ventilation.

Japanese Patent Laid-Open No. 2007-12094

  Then, this invention makes it a subject to provide the gas alarm which can eliminate a user's anxiety by telling a user whether the ventilation after alarm generation is effective.

The invention according to claim 1, which has been made to solve the above-described problem, generates a warning when a gas sensor for detecting a gas concentration of a gas to be detected and a gas concentration detected by the gas sensor exceeds an alarm value. A gas alarm device comprising: an alarm generating means configured to reduce a gas concentration detected by the gas sensor after the gas concentration detected by the gas sensor is equal to or higher than an alarm value and lower than a threshold value greater than the alarm value Gas detected by the gas sensor after the first alarm generation period until the gas concentration is reached and after the first alarm generation period and the gas concentration detected by the gas sensor falls below a threshold value greater than the alarm value The alarm generation means is provided so that the alarm generated during the second alarm generation period until the concentration becomes less than the alarm release value is different, Means, the first alarm period the alarm generating means in the, when a sound is outputted from the speaker, to output repeatedly a sound of the same language, so repeat the same ringing If for sounding the buzzer, light emitting In the case of lighting the element, the same lighting is repeated, and the gas alarm device is characterized.

The invention according to claim 2 is such that the alarm generation means returns to the same alarm as the first alarm generation period when the gas concentration detected by the gas sensor rises again during the second alarm generation period. It exists in the gas alarm device of Claim 1 provided.

According to a third aspect of the present invention, the alarm generating means intermittently sounds an alarm sound or intermittently lights a light emitting element during the first alarm generation period, and during the first alarm generation period during the second alarm generation period. so as to intermittent lighting it was intermittently sounding or the light emitting element the alarm sound at longer intervals than, existing in the gas alarm device according to claim 1, characterized in that are provided.

According to a fourth aspect of the present invention, the alarm generation means intermittently sounds an alarm sound or intermittently lights a light emitting element during the first alarm generation period, and during the first alarm generation period during the second alarm generation period. It exists in the gas alarm device of Claim 3 provided so that the said alarm sound may be intermittently sounded or the said light emitting element may be lighted intermittently at a longer space | interval.

As described above , according to the first aspect of the present invention, when ventilation is performed after the gas concentration becomes equal to or higher than the alarm value and an alarm is generated, the gas concentration decreases to become lower than the threshold value and approaches the alarm value. When this gas concentration falls below the threshold value and approaches the alarm value, the alarm changes from the first alarm generation period to the second alarm generation period, so the user can be informed that there is an effect on ventilation after the alarm occurs, The user's anxiety can be resolved. In addition, since the alarm can continue to be generated even after the gas concentration falls below the threshold value, there is no possibility that the user stops the ventilation when the ventilation is not sufficiently performed.

According to the second aspect of the present invention, when the gas concentration rises again after the gas concentration is equal to or lower than the threshold value and the second alarm generation period is reached, the first alarm generation period is resumed. Can be informed.

According to invention of Claim 3 , an alarm can be easily varied using an alarm sound or a light emitting element.

  According to the fourth aspect of the present invention, it is possible to tell the user in detail how much the ventilation effect is.

It is a block diagram which shows the structure of the gas alarm device in a 1st reference example . It is a flowchart which shows the process sequence of CPU which comprises the gas alarm device shown in FIG. (A)-(D) is a time chart which respectively shows the gas concentration in a 1st reference example , the output of the gas sensor shown in FIG. 1, the sounding state of an alarm buzzer, and the lighting state of an alarm lamp. It is a graph which shows the relationship between gas concentration, the ringing interval of the alarm buzzer shown in FIG. 1, and the lighting interval of an alarm lamp. It is a block diagram which shows the structure of the gas alarm device of this invention in a 2nd reference example . (A)-(D) is a time chart which respectively shows the gas concentration in a 2nd reference example , the output of the gas sensor shown in FIG. 5, the output state of an alarm speaker, and the lighting state of an alarm lamp. (A)-(E) is a time chart which respectively shows the gas concentration in 1st Embodiment, the output of a gas sensor, the sounding state of an alarm buzzer, the output state of an alarm speaker, and the lighting state of an alarm lamp. It is a flowchart which shows the process sequence of CPU which comprises the gas alarm device in 2nd Embodiment. (A)-(C) is a time chart which respectively shows the output of the gas sensor shown in FIG. 1 in 2nd Embodiment, the lighting state of an alarm lamp, and the ringing state of an alarm buzzer. (A)-(C) is a time chart which respectively shows the output of the gas sensor shown in FIG. 1 in 2nd Embodiment, the lighting state of an alarm lamp, and the ringing state of an alarm buzzer. (A)-(C) is a time chart which respectively shows the output of the gas sensor shown in FIG. 1 in 2nd Embodiment, the lighting state of an alarm lamp, and the ringing state of an alarm buzzer.

(First Reference Example)
Hereinafter, it will be explained with reference to FIGS. 1 to 4 the Ruga scan alarm put to the first exemplary embodiment. As shown in the figure, the gas alarm device 1 includes a gas sensor 2, a microcomputer 3 (hereinafter referred to as μCOM), an alarm buzzer 4, and an alarm lamp 5. The gas sensor 2 is a known catalytic combustion type or semiconductor type sensor, and detects the gas concentration of a detection target gas such as city gas, LP gas, or carbon monoxide gas. The μCOM 3 is a computer that controls the entire gas alarm device 1, monitors the gas concentration detected by the gas sensor 2, and controls an alarm buzzer 4 and an alarm lamp 5 described later when the gas concentration exceeds an alarm value. To generate an alarm.

  The μCOM 3 includes a central processing unit (CPU) 31 that performs various processes according to a program, a ROM 32 that is a read-only memory storing a program for processing performed by the CPU 31, and a work that is used in various processes in the CPU 31. And a RAM 33 which is a readable / writable memory having an area, a data storage area for storing various data, and the like. The alarm buzzer 4 is a device that generates a buzzer sound (alarm sound) in accordance with the control of the μCOM 3. The alarm lamp 5 is a light emitting element that emits light according to the control of μCOM 3.

  Next, the operation of the gas alarm device 1 configured as described above will be described below with reference to FIGS. In response to the power-on of the gas alarm device 1, the CPU 31 starts the operation shown in FIG. First, the CPU 31 controls the gas sensor 2 to detect the gas concentration of the detection target gas, and takes in the gas concentration (step S1). Thereafter, the CPU 31 determines whether or not the taken-in gas concentration is equal to or higher than an alarm value (step S2). As shown in FIGS. 3 (A) and 3 (B), gas leakage, incomplete combustion, and the like occur, and the gas concentration of the detection target gas in the atmosphere around the gas alarm device 1 increases, and in accordance with this, the gas sensor 2 When the gas concentration detected by the above becomes equal to or higher than the alarm value (Y in step S2), the CPU 31 continuously sounds the alarm buzzer 4 and continuously lights the alarm lamp 5 to generate an alarm (step S3). This warning can notify the user that the gas concentration has reached or exceeded the warning value.

  Thereafter, the CPU 31 controls the gas sensor 2 again to detect the gas concentration of the detection target gas, and takes in the gas concentration (step S4). Next, the CPU 31 determines whether or not the gas concentration is lowered based on the gas concentration taken in step S4 (step S5). As the determination of the decrease, for example, it is determined that the gas concentration is decreased when the gas concentration taken in step S4 is equal to or lower than the gas concentration taken in the previous step S4 twice. When the user opens the door or window and performs ventilation according to the alarm in step S3, the gas concentration of the detection target gas in the atmosphere around the gas alarm device 1 decreases as shown in FIGS. 3 (A) and 3 (B). .

  In response to this, when the CPU 31 determines that the gas concentration detected by the gas sensor 2 has decreased (Y in step S5), the ringing interval of the alarm buzzer 4 and the alarm lamp according to the gas concentration detected immediately before 5 is set (step S6), the alarm buzzer 4 is intermittently sounded (boo) at the set sounding interval, and the alarm lamp 5 is intermittently lighted at the set lighting interval (step S7). In addition, as shown in FIG. 4, the ringing interval and the lighting interval are set to become slower as the gas concentration becomes lower. Thus, by changing from continuous ringing and continuous lighting to intermittent ringing and intermittent lighting, it is possible to notify the user that the gas concentration has started to decrease due to the effect of ventilation.

  Thereafter, the CPU 31 controls the gas sensor 2 again to detect the gas concentration of the detection target gas, and takes in the gas concentration (step S8). If the gas concentration taken in step S8 is not less than or equal to the alarm value (N in step S9), the process returns to step S6 again. At this time, in step S6, a ringing interval and a lighting interval corresponding to the gas concentration taken in in step S8 are newly set. Therefore, if ventilation progresses and the gas concentration decreases, the sounding interval of the alarm buzzer 4 and the lighting interval of the alarm lamp 5 become gradually slower. Further, when the ventilation further proceeds and the gas concentration becomes equal to or lower than the alarm value (Y in Step S9), the CPU 31 stops the alarm by the alarm buzzer 4 and the alarm lamp 5 (Step S10), and then returns to Step S1 again.

  As is clear from the above, the CPU 31 functions as an alarm generating means in the claims. Further, according to the above-described operation, as shown in FIG. 3, the first alarm generation period T1 when the gas concentration detected by the gas sensor 2 starts to decrease after the gas concentration detected by the gas sensor 2 becomes equal to or higher than the alarm value. During this, the alarm buzzer 4 sounds continuously and the alarm lamp 5 lights continuously. Further, after the first alarm generation period T1, an alarm is given during the second alarm generation period T2 from when the gas concentration detected by the gas sensor 2 starts to decrease until the gas concentration detected by the gas sensor 2 becomes lower than the alarm value. The buzzer 4 sounds intermittently and the alarm lamp 5 lights intermittently. That is, the alarm can be made different between the first alarm generation period T1 and the second alarm generation period T2.

  Therefore, when the gas concentration starts to decrease, the first alarm generation period T1 changes to the second alarm generation period T2, and the alarm changes from continuous ringing and continuous lighting to intermittent ringing and intermittent lighting. It is possible to tell the user that there is a problem, and the user's anxiety can be resolved. Moreover, since the alarm can be continuously generated even after the gas concentration starts to decrease, there is no possibility that the user stops the ventilation in a state where the ventilation is not sufficiently performed.

  Further, according to the gas alarm device 1 described above, the alarm buzzer 4 is continuously sounded during the first alarm generation period T1, the alarm lamp 5 is continuously lit, and the alarm buzzer 4 is intermittently sounded during the second alarm generation period T2. And the alarm lamp 5 is intermittently lit. Thus, the alarm can be easily changed using the alarm buzzer 4 and the alarm lamp 5.

  Further, according to the gas alarm device 1 described above, the ringing interval of the alarm buzzer 4 and the lighting interval of the alarm lamp 5 are delayed according to the decrease in the gas concentration detected by the gas sensor 2 during the second alarm generation period T2 ( Change). Thereby, it is possible to tell the user in detail how much the ventilation effect is.

(Second reference example)
It will now be described with the Ruga scan alarm put in the second reference example with reference to FIGS. In FIG. 5, parts equivalent to those of the gas alarm device 1 already described in the first reference example described above with reference to FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. The difference between the first embodiment and the second embodiment is that an audio output circuit 6 and an alarm speaker 7 are provided in place of the alarm buzzer 4. The audio output circuit 6 is a circuit that outputs an audio signal to an alarm speaker 7 to be described later according to the control of the μCOM 3. The alarm speaker 7 outputs a sound corresponding to the sound signal output from the sound output circuit 6.

In the first reference example described above, as shown in FIG. 3, the CPU 31 continuously sounds the alarm buzzer 4 in the first alarm generation period T1, and intermittently sounds the alarm buzzer 4 in the second alarm generation period T2. On the other hand, in the second reference example , as shown in FIG. 6, the CPU 31 controls the audio output circuit 6 to check whether the gas is leaking from the alarm speaker 7 during the first alarm generation period T1. Are repeatedly output, and during the second alarm generation period T2, the alarm speaker 7 repeatedly outputs the sound “Ventilation effect has been produced. In this way, the user can be surely told that the ventilation is effective by using the voice.

(First embodiment)
Next, the gas alarm device of the present invention in the first embodiment will be described with reference to FIG. Since the structure of the gas alarm device 1 of 1st Embodiment is the same as that of the 1st or 2nd reference example , detailed description is abbreviate | omitted here. In the first and second reference examples described above, as shown in FIG. 3 and FIG. 6, the first alarm generation period T < b > 1 and the first alarm generation occur until the gas concentration starts to decrease after the gas concentration exceeds the alarm value. The second alarm generation period T2 is after the period T1 until the gas concentration falls below the alarm value after the gas concentration starts to decrease. On the other hand, in the first embodiment , as shown in FIG. 7, after the gas concentration becomes higher than the alarm value, the gas concentration starts to decrease until it becomes lower than the threshold value larger than the alarm value and approaches the alarm value. The second alarm generation period T2 may be a period after the first alarm generation period T1 and the first alarm generation period T1 until the gas concentration becomes equal to or less than the alarm value after the gas concentration becomes equal to or less than the threshold value.

Also in this case, as in the first and second reference examples , as shown in FIG. 7, the alarms generated in the first alarm generation period T1 and the second alarm generation period T2 are made different. Similarly, in the first embodiment, when the gas concentration falls below the threshold value, the first alarm generation period T1 is changed to the second alarm generation period T2, and the alarm is changed, which is effective for ventilation after the alarm generation. Can be communicated to the user, and the user's anxiety can be resolved. In addition, since the alarm can continue to be generated even after the gas concentration falls below the threshold value, there is no possibility that the user stops the ventilation when the ventilation is not sufficiently performed.

(Second Embodiment)
Next, the gas alarm device of this invention in 2nd Embodiment is demonstrated with reference to FIGS. Since the configuration of the gas alarm device 1 of the second embodiment is the same as that of the first and second reference examples and the first embodiment, detailed description thereof is omitted here. The operation of the gas alarm device 1 in the second embodiment will be described below with reference to FIG. In response to the power-on of the gas alarm device 1, the CPU 31 starts the operation shown in FIG. First, the CPU 31 controls the gas sensor 2 to detect the gas concentration of the detection target gas, and takes in the gas concentration (step S11).

Thereafter, the CPU 31 determines whether or not the taken-in gas concentration is equal to or higher than an alarm value (step S12). As shown in FIG. 9A, gas leakage, incomplete combustion, and the like occur, and the gas concentration of the detection target gas in the atmosphere around the gas alarm device 1 increases, and is detected by the gas sensor 2 accordingly. When the gas concentration is higher alarm value (Y in step S12), CPU 31 becomes the alarm condition, an alarm by intermittently light the alarm lamp 5 the alarm buzzer 4 at intervals T ₃₁ also causes intermittent sounds at intervals T ₃₁ (Step S13).

  Thereafter, the CPU 31 controls the gas sensor 2 again to detect the gas concentration of the detection target gas, takes in the gas concentration (step S14), and if the taken-in gas concentration has increased to an alarm value +600 mV or higher (step S14). In S15, Y), the detection of the gas concentration is repeated (step S16), and it is determined whether or not the gas concentration has dropped below the alarm value +550 mV (threshold) (step S17). When the user opens the door or window and performs ventilation in accordance with the alarm in step S13, the gas concentration of the detection target gas in the atmosphere around the gas alarm device 1 decreases as shown in FIG.

In response to this, when the CPU 31 determines that the gas concentration detected by the gas sensor 2 has decreased to less than the alarm value +550 mV (Y in step S17), the alarm buzzer transitions from the alarm state to the second stop, and the alarm buzzer. 4 of the ringing interval and lighting interval of the alarm lamp 5 is changed to a long interval T ₃₂ than the interval T ₃₁ (step S18). Thereafter, the CPU 31 detects the gas concentration again (step S19), determines whether or not the gas concentration has increased again to the alarm value +600 mV or more (step S20), and the alarm value +200 mV without increasing the gas concentration. Judgment is made as to whether or not it has fallen below (step S21).

As shown in FIG. 9, when the gas concentration falls below the alarm value +200 mV without increasing above the alarm value +600 mV (N in step S20 and Y in step S21), the CPU 31 stops sounding from the second stop. the transition to the first stage, to change the ringing interval and lighting interval of the alarm lamp 5 of the alarm buzzer 4 long interval T ₃₃ than the interval T ₃₂ (step S22). Thereafter, the CPU 31 detects the gas concentration again (step S23), determines whether or not the gas concentration has increased again to the alarm value +250 mV or more (step S24), and further cancels the value without increasing the gas concentration. Judgment is made as to whether or not it has fallen below (step S25).

  As shown in FIG. 9, when the gas concentration falls below the release value without increasing above the alarm value +250 mV (N in step S24 and Y in step S25), the CPU 31 switches from the first stop to the monitoring state. After making a transition and stopping the alarm by the alarm buzzer 4 and the alarm lamp 5 (step S26), the process returns to step S11 again.

On the other hand, as shown in FIG. 10, a gas having a gas concentration of alarm value +600 mV or higher is generated (Y in step S15), and then the ventilation is performed. As a result, the gas concentration is lowered to alarm value +550 mV Nevertheless, if the gas concentration rises above the alarm value +600 mV again for some reason (Y in step S17) again (Y in step S20), the CPU 31 transitions from the second stop to the alarm state, and the alarm buzzer 4 and sounding interval of the alarm lamp 5, after returning the lighting interval from the interval T ₃₂ the interval T ₃₁ (step S27), returns to step S16.

  Thereafter, as shown in FIG. 10, the gas concentration does not rise again, but decreases to an alarm value +550 mV (Y in step S17), an alarm value +200 mV (Y in step S21), and a release value (Y in step S24). Each time, the gas alarm device 1 transits from the alarm state (step S13) to the second ringing stop (step S22) to the first ringing stop (step S23) to the monitoring state (step S26).

Further, as shown in FIG. 11, a gas having a gas concentration of alarm value +600 mV or more is generated (Y in step S15), and then the ventilation is performed. As a result, transition from alarm state → second ringing to first ringing is performed. Then, although the gas concentration has decreased to less than the alarm value +200 mV (Y in step S21), if the gas concentration rises again above the alarm value +250 mV for some reason (Y in step S24), the CPU 31 transition from sound ceased one stage to the alarm state, the process returns to step S13, return ringing interval of the alarm buzzer 4 and alarm lamp 5, the lighting interval from the interval T ₃₃ the interval T _31.

  After returning to the alarm state, if the gas concentration does not exceed the alarm value +600 mV (N in step S15), the gas concentration will be the release value without returning to the second ringing and the first ringing even if the gas concentration decreases. If it is less (Y in step S28), the alarm state is changed to the monitoring state, the alarm by the alarm buzzer 4 and the alarm lamp 5 is stopped (step S26), and the process returns to step S11.

  Furthermore, even if the gas concentration is equal to or higher than the alarm value (Y in step S12), if the gas concentration is not equal to or higher than the alarm value +600 mV (N in step S15), the CPU 31 stops sounding even if the gas concentration decreases. If the gas concentration falls below the release value without transitioning to the second stage and the first stage of squealing (Y in step S28), the alarm state is changed to the monitoring state, and the alarm by the alarm buzzer 4 and the alarm lamp 5 is stopped. (Step S26), the process returns to Step S11.

Also in this case, the alarms generated in the first alarm generation period T1 and the second alarm generation period T2 are made different, as in the first and second reference examples and the first embodiment. Similarly, in the second embodiment, when the gas concentration decreases and becomes less than the alarm value +550 mV, the alarm is changed from the first alarm generation period T1 to the second alarm generation period T2, which is effective for ventilation after the alarm is generated. It is possible to tell the user that there is a problem, and the user's anxiety can be resolved. Further, since the alarm can continue to be generated even after the gas concentration is reduced to the alarm value +550 mV or less, there is no possibility that the user stops the ventilation in a state where the ventilation is not sufficiently performed.

Further, according to the gas alarm device 1 described above, the alarm buzzer 4 is intermittently sounded during the first alarm generation period T1, the alarm lamp 5 is intermittently lit, and the first alarm generation period T1 during the second alarm generation period T2. The alarm buzzer 4 is intermittently sounded at intervals T ₃₂ and T ₃₃ (> T ₃₁ ) longer than that, and the alarm lamp 5 is lit intermittently. Thus, the alarm can be easily changed using the alarm buzzer 4 and the alarm lamp 5.

  Further, according to the gas alarm device 1 described above, the ringing interval of the alarm buzzer 4 and the lighting interval of the alarm lamp 5 are stepwise according to the decrease in the gas concentration detected by the gas sensor 2 during the second alarm generation period T2. Slow (change). Thereby, it is possible to tell the user in detail how much the ventilation effect is.

  Further, according to the gas alarm device 1 described above, when the gas concentration detected by the gas sensor rises again during the second alarm generation period T2, the gas alarm device 1 returns to the first alarm generation period T1. This can inform the user that the gas concentration has increased again.

In addition, according to 1st-2nd embodiment mentioned above, although any one of the warning by a sound and the warning by a buzzer sound was performed, this invention is not limited to this. You may make it perform both the warning by a sound and the warning by a buzzer sound.

In the present invention, the alarms generated in the first alarm generation period T1 and the second alarm generation period T2 may be different from each other. As a method for differentiating the alarms, the first to second implementations described above may be used. It is not limited to what was demonstrated with the form.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

2 Gas sensor 5 Alarm lamp (light emitting means)
31 CPU (alarm generating means)
T1 first alarm generation period T2 second alarm generation means

Claims (4)

In a gas alarm device comprising: a gas sensor for detecting a gas concentration of a gas to be detected; and an alarm generating means for generating an alarm when the gas concentration detected by the gas sensor exceeds an alarm value.
A first alarm generation period from when the gas concentration detected by the gas sensor becomes greater than or equal to an alarm value until the gas concentration detected by the gas sensor decreases and falls below a threshold value greater than the alarm value; Generation of a second alarm after the alarm generation period and after the gas concentration detected by the gas sensor becomes less than or equal to a threshold value greater than the alarm value until the gas concentration detected by the gas sensor becomes less than the alarm release value The alarm generation means is provided so that alarms generated during the period are different,
During the first alarm generation period, when the alarm generation means outputs sound from the speaker, the sound of the same wording is repeatedly output, and when the buzzer sounds, the same sounding is repeated and the light emitting element is turned on. A gas alarm characterized by causing the same lighting to be repeated . The alarm generation means is provided so as to return to the same alarm as the first alarm generation period when the gas concentration detected by the gas sensor rises again during the second alarm generation period. The gas alarm device according to claim 1. The alarm generation means intermittently sounds an alarm sound or intermittently lights a light emitting element during the first alarm generation period, and the alarm sound is emitted at a longer interval during the second alarm generation period than during the first alarm generation period. The gas alarm device according to claim 1, wherein the gas alarm device is provided so as to intermittently ring or intermittently light the light emitting element. The alarm generation means is provided such that the alarm sounding interval or the light emitting element lighting interval changes according to a decrease in gas concentration detected by the gas sensor during the second alarm generation period. The gas alarm device according to claim 3.

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