JPH0765743B2 - Gas shutoff device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shutoff device that automatically shuts off a gas passage when an abnormality occurs to prevent an accident such as an explosion or poisoning caused by city gas or propane gas. Regarding

2. Description of the Related Art Conventionally, as shown in FIG. 5, a conventional gas shutoff device of this type includes a flow rate measuring means 1 for issuing a signal according to the amount of gas passing through a gas meter provided in a gas supply line, and the flow rate measuring means. A usage state detection unit 2 that detects the usage state of gas by the flow rate signal sent, an initial condition storage unit 3 that stores gas proper usage conditions as initial values in advance, and a signal from the usage state detection unit is the gas proper usage conditions. If it deviates from the range, it is judged to be abnormal and a proper use condition determination unit 4 that outputs a cutoff signal, a timer 5 that counts a first predetermined time, a start signal application unit 6 that starts the timer, and the use state detection unit Of the gas use state during operation of the timer by a signal from the use state storage operation unit 7 for calculating the use condition based on the stored use state, and the use state storage operation unit. A proper use condition setting changing section 8 for comparing the output with the initial condition and changing a predetermined value as a new proper use condition, and a shutoff means 9 for shutting off the gas passage in response to a shutoff signal from the proper use condition determining section. Then, after the appropriate use condition is changed by the appropriate use condition setting changing unit 8, the changed appropriate use condition is multiplied by a predetermined value to obtain an appearance rate observation region of the use state. A second timer 11 for counting a second predetermined time, a provisional proper use condition calculation unit 12 for calculating a signal of a use state detection unit to provisionally set a proper use condition, and the appearance rate observation area. It is determined whether or not the signal of the usage state detection unit has been input to the second timer, and when the signal is first input, a start signal to the second timer is output, and the provisional appropriate usage condition calculation unit is provided with the appropriate usage condition. A temporary setting signal is output to the setting change section. In order to output the start signal, the gas use state that enters the appearance rate observation area during the operation of the second timer is stored, and further, the use condition of the appearance rate observation area is calculated based on the stored use state. It was composed of a usage state storage / calculation unit 13 and an appropriate usage condition temporary storage unit 14 for storing the current appropriate usage conditions. (For example, JP-A-1-203818) Here, the proper use conditions include the capacity of each gas meter, the total flow rate set according to the gas appliances owned by the gas user, the individual maximum flow rate, the continuous use time, and the like. Indicates an item. The total flow rate is the total flow rate of the gas that passes through the gas meter within the predetermined measurement period.If the current total flow rate exceeds the set predetermined value, such as when the gas hose is disconnected or the gas appliances burn out, it is judged as abnormal. Judgment is a use condition for operating the interruption device. Individual maximum flow rate is the number of gas appliances currently in use by detecting the change in gas flow rate for each predetermined measurement period, and identifying how much gas consumption is in each type. When the amount exceeds the set value, a shut-off signal is output to the shut-off means to deal with gas leaks such as cracks in the gas hose and burning out when the gas plug is half-opened. In addition, the continuous use time is the continuous usable time set for each area from the statistical data of the time when the gas appliance in a certain combustion area is continuously used, and the data from the usage state detection unit is the set time. When a certain time has passed, an operation signal is sent to the shutoff device to ensure safety even if the gas appliance is forgotten to be turned off.

With the above-described configuration, when the activation signal is applied to the first timer, the counting of the predetermined time is started, and at the same time, the gas usage pattern during the time is measured by the operation of the usage status storage / calculation unit. That is, during this time, the measured values of the above-mentioned total flow rate, maximum individual flow rate, continuous use time, etc. are updated, and at the same time as the timer ends, the final data is multiplied by a predetermined value in the use state storage calculation unit and gas is used properly. It is sent to the condition setting change section. The proper use condition setting changing unit compares the initial condition with the data of the storage operation unit and newly sets a predetermined gas proper use condition. Thereafter, the proper use condition determination unit compares the new setting condition with the signal from the use state detection unit, and if the condition is not satisfied, determines that the condition is abnormal and activates the shutoff means.
Further, the proper use condition setting changing unit stores the current proper use condition in the proper use condition temporary storage unit at the time when the provisional setting signal from the provisional proper use condition calculating unit is input, and at the same time stores the provisional setting signal in the proper use condition. After changing the setting, the appropriate use condition is changed according to the signal from the use state storage operation unit of the appearance rate observation area during the second timer period or the signal from the temporary storage unit. Then, the appearance rate observation area is set by multiplying the proper use condition by a predetermined value.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-mentioned configuration, uniform means for setting each appropriate usage condition by multiplying a predetermined value by each appearance rate observation area is applied, and particularly in the usage pattern of gas appliances. There was an appearance rate observation area that was not set accordingly. That is, although the combustion area of a gas stove and the like and the combustion area of a gas table and the like are substantially the same, their continuous use time is quite different, and in these combustion areas the use of the stove is started from summer to winter. In such a case, there is a problem that the actual stove usage pattern does not adapt in the above setting of the appearance rate observation area, and there is a case where the time is cut off without the second timer operating.

The present invention solves such a conventional problem, paying attention to the difference in the actual use pattern of a heating appliance such as a gas stove and a cooking appliance such as a gas table, and a new logic through the presence detection of a person who uses the gas appliance. By applying it, it aims at providing the gas cutoff device which does not have unnecessary cutoff.

Means for Solving the Problems In order to solve the above problems, the gas shutoff device of the present invention is a flow rate detection unit that emits a signal according to the passing gas amount of a gas meter provided in a gas supply line, and the flow rate detection unit. A flow rate calculation unit that calculates the gas flow rate with a flow rate signal sent from
An initial condition storage unit that stores the proper continuous use time condition as an initial value in advance, and if the time during which the same flow rate signal obtained from the flow rate calculation unit continues is outside the proper continuous use time condition, it is judged to be abnormal and shut off. A proper continuous use time determination unit that outputs a signal, a first timer that counts a first predetermined time, a start signal application unit that starts the first timer, and a signal from the flow rate calculation unit that enables the first A continuous use time storage calculation unit for calculating a use time condition based on the continuous use time for each gas flow rate during operation of the first timer, and outputting a calculation result at the end of the first timer operation; Output and the initial conditions are compared and a predetermined value is set and changed as a new proper continuous use time condition, and an appropriate continuous use time setting changing unit and a cutoff signal from the appropriate continuous use time determining unit are responded to. And interrupting means for interrupting the gas passage Te,
After the appropriate continuous use time condition is set by the appropriate continuous use time setting changing unit according to the gas flow rate signal, the changed appropriate use time is multiplied by a predetermined value to set a monitoring area for each appropriate continuous use time condition. The appearance rate observation area setting unit, a second timer that counts a second predetermined time, and a temporary appropriate continuous use time in the appropriate continuous use time determination unit according to a predetermined flow rate signal obtained from the flow rate calculation unit. There was a change in the flow rate above a predetermined value by inputting a signal from the provisional proper continuous use time condition calculation unit that outputs a provisional setting signal to the appropriate continuous use time setting change unit so as to apply the condition When the flow rate change detection unit that sends out a signal and the appearance rate observation area set according to the predetermined flow rate signal, it is determined whether or not the time from the start to the end of the flow of the predetermined gas flow has entered Time point, Or, when a signal from the flow rate change detection unit is received while the predetermined gas flow rate continues, and when the continuous use time of the predetermined gas flow rate signal enters the appearance rate observation area, the second And a start signal to the provisional proper continuous use time condition calculation unit to output a provisional setting signal to the proper continuous use time setting change unit, and the second Appearance rate observation that stores the continuous use time state according to the flow rate signal that enters the appearance rate observation area during timer operation, and further calculates an appropriate continuous use time condition when the stored continuous use time state is a predetermined number of times or more Area continuous use time storage processing unit, and a current appropriate continuous use time condition temporary storage unit for storing the current appropriate continuous use time condition temporary storage unit, the appropriate continuous use time setting change unit, the provisional appropriate continuous use time condition After the current proper continuous use time condition is stored in the proper continuous use time condition temporary storage unit at the time when the temporary setting signal from the arithmetic unit is input, and the temporary setting signal is changed as the proper continuous use time condition, Signal from the continuous use time storage processing unit of the appearance rate observation area at the end of the operation of the second timer, or
When the signal from the temporary storage unit is input and the signal from the former is calculated so as to change the appropriate continuous use time condition, the signal is also input, and the signal from the former is the appropriate continuous use time condition. If the latter signal is not calculated to be changed, the latter signal is set and changed as an appropriate continuous use time condition.

Action The present invention, by the above-described configuration, first detects the actual gas consumption pattern in the period in which the first timer operates, and sets the appropriate continuous use time condition of the meter-installed household based on the data, and at the same time, Even after the time-out, the gas usage condition that enters the monitoring area is constantly monitored, and if data appears in the appearance rate observation area, provisional appropriate continuous usage time conditions are set and the second timer is activated to measure data. When the change condition is satisfied, the proper continuous use time condition is reset.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a functional block diagram of a gas cutoff device of the present invention, which is a flow rate detection unit 15 which emits a signal according to the amount of gas passing through a gas meter provided in a gas supply line, and a flow rate signal sent from the flow rate detection unit. Flow rate calculator 16 that calculates gas flow rate with
And an initial condition storage unit 17 that stores a proper continuous use time condition as an initial value in advance, and it is determined to be abnormal if the time during which the same flow rate signal obtained from the flow rate calculation unit continues is outside the proper continuous use time condition. Appropriate continuous use time determination unit 18 that outputs a shutoff signal, a first timer 19 that counts a first predetermined period, a start signal application unit 20 that starts the first timer, and the flow rate calculation unit. From the signal, the continuous use time for each gas flow rate during the operation of the first timer is stored, and the use time condition is calculated based on the stored continuous use time, and the calculation result at the end of the operation of the first timer 19 Proper continuous use time setting for changing the preset value as a new proper continuous use time condition by comparing the output of the continuous use time storage operation unit 21 with the output of the continuous use time storage operation unit and the initial condition A changing unit 22, a shutoff unit 23 that shuts off the gas passage in response to a shutoff signal from the appropriate continuous use time determination unit, and a proper continuous use time condition according to the gas flow rate signal in the appropriate continuous use time setting change unit. After the setting, the appearance rate observation area setting unit 24 that multiplies the changed appropriate use condition by a predetermined value to set the observation area for each appropriate continuous use time condition, and the second appearance period observation area setting unit 24 that counts the second predetermined period. timer
25, a provisional proper continuous use time condition calculation unit 26 that temporarily sets an appropriate continuous use time condition according to a predetermined flow rate signal obtained from the flow rate calculation unit, and a signal from the flow rate calculation unit is input to a predetermined value or more. Flow rate change detection unit 27 that sends a signal when there is a change in flow rate, and whether or not the time from the beginning to the end of the flow of the predetermined gas flow within the appearance rate observation area set according to the predetermined flow rate signal When the first entry is made, or after the signal from the flow rate change detection unit is present while the predetermined gas flow rate is continuing, the continuous use time of the predetermined gas flow rate signal in the appearance rate observation area At the time of entering, a start signal is output to the second timer, and a start signal is output to the temporary proper continuous use time condition calculating unit to output a temporary setting signal to the proper continuous use time setting changing unit. When output The continuous use time state corresponding to the flow rate signal entering the appearance rate observation area during the operation of the second timer is stored, and an appropriate continuous use time condition is calculated when the stored continuous use time state is a predetermined number of times or more. The continuous use time storage processing unit 28 of the appearance rate observation area and the proper continuous use time condition temporary storage unit 29 that stores the current appropriate continuous use time condition are included.

In the above configuration, the appropriate continuous use time setting changing unit 22 is
When the temporary setting signal from the temporary appropriate continuous use time condition calculation unit 26 is input, the current appropriate continuous use time condition is stored in the appropriate continuous use time condition temporary storage unit 29, and the temporary setting signal is changed to the appropriate continuous use time condition. After changing the setting as
At the end of the operation of the timer 25, the signal from the continuous use time storage processing unit 28 in the appearance rate observation area or the signal from the temporary storage unit 29 is input, and the signal from the former should change the appropriate continuous use time condition. If the signal is calculated, the signal is changed, and if the signal from the former is not calculated to change the appropriate continuous use time condition, the latter signal is changed as the appropriate continuous use time condition. .

Next, FIG. 2 shows the relationship between the gas combustion amount calculated from the explosion limit of the raw gas leakage amount and the continuous use time, as well as the actual use survey of gas appliances in each home. The horizontal axis represents the gas combustion amount, and the vertical axis represents the continuous use time condition. That is, the time limit level that can be continuously used for each combustion amount is shown.
L1 has a stove, that is, there is a time limit level determined from the actual usage when using the stove and the explosion limit at the time of gas leakage in each combustion amount range shown in the figure. Also, L2
Is the time limit level determined from the actual usage of other gas appliances without the stove, that is, when the gas stove is not used. Here, the time limit is set short when the gas stove is not used. And on the horizontal axis, from 500 (kcal / h) to 5000 (kcal / h) is the same division of the combustion amount range, similarly, from 5000 (kcal / h) to 6000 (kcal / h), 6000 (kcal / h) to 7000 (kcal
/ h) and so on, divided by the amount of combustion. These categories are calculated from the explosion limits, and each category corresponds to a given gas combustion appliance.

Fig. 3 shows that data was generated in the appearance rate observation area after the appropriate continuous use time condition was set for the combustion amount range from 500 (kcal / h) to 5000 (kcal / h), Shows that the timer has been activated. The horizontal axis represents elapsed time and the vertical axis represents continuous use time. Timer 1 counts up at time t ₀ , the proper continuous use time condition is set to 160 minutes of L2 (no stove), and then the appropriate continuous use time condition set by the appearance rate observation area setting unit is set. The monitoring area for continuous use time (here, 128 minutes) is set by multiplying by a predetermined number. The x-marks represent the observed data, that is, the time values for continuous use in the above combustion amount range. It can be seen that from 128 minutes to L2 (160 minutes) of the alternate long and short dash line is the monitoring area of the continuous use time in this combustion amount range, and at time t ₁ , data is generated in the monitoring area. At this timing, the continuous use time storage processing unit of the appearance rate observation area outputs a start signal to the provisional appropriate continuous use time condition calculation unit so that the appropriate continuous use time setting changing unit outputs a setting signal, and The continuous use time state corresponding to the flow rate signal entering the appearance rate observation area during the operation of the second timer is stored. That is, at time t _1, the cutoff condition for continuous use time is provisionally set to 720 minutes of L 1 (with a stove), and the second timer starts counting and until the time t ₃ when counting up, It is determined whether or not data has occurred in the monitoring area from the 128-minute dotted line to L1 (720 minutes). In this embodiment, during the second timer period, appropriate continuous use time conditions it with the more data three times surveillance area occurs time t ₃ is L1
The setting has been changed to "with stove". Here, it can be seen that the lower limit value of the appearance rate observation area is set to 128 minutes and the upper limit value is changed from L2 to L1 at time t ₁ . Also, the time t ₃ when the appropriate continuous use time condition is changed to L1
After that, since there is no cutoff condition corresponding to L1 or higher, the appearance rate observation area is not set.

By the way, in the combustion amount range from about 500 (kcal / h) to about 5000 (kcal / h), including heating appliances such as gas stoves,
There are cooking utensils such as a gas rice cooker, a gas table, a gas stove, and a gas oven. The following table shows the main rated gas combustion amounts.

The standard usage of each of the above gas combustion appliances is shown below.

First of all, the continuous use time with the same burning amount in the cookware is about 15 minutes on the gas rice cooker or the grill of the gas table, and on the gas table depending on the cooking menu, about 20 minutes or less of soup, steamed or baked food, Also, most stews and stews are within 30 minutes to 1 hour. Moreover, it is common to use the gas oven within about 30 times.

Next, in the case of a gas stove for heating equipment, the lower the outside air temperature, the longer it will last for about 5 to 10 hours, but how to use it at the turn of the season from autumn to early winter is 1 It is a normal continuous use time from about 2 hours to about 2 hours from evening to night.

In this way, the same about 500 (kcal / h) to about 5000 (kcal / h)
Even for gas combustion appliances that belong to the combustion amount range up to h), the duration of continuous combustion varies depending on the type and the case of use.

Next, FIG. 4 shows an embodiment to which the present invention is applied when the gas stove is continuously used for a long time in the state where the usage time cutoff condition is L2 and there is no stove. The horizontal axis represents the elapsed time, and the vertical axis represents the gas combustion amount. At time t _1, the combustion amount Q _{1 of the} gas stove begins to flow, and the continuous use time storage processing unit in the appearance rate observation area starts time counting. At time t _2, another gas appliance is started to be used, and the gas combustion amount Q 2 is observed. At this point in time, the flow rate change detection unit displays a predetermined value (for example, 3
%), The above change is detected, and a signal indicating that there is a change is input to the continuous use time storage processing unit in the appearance rate observation area. Although not shown in the figure, the processing unit also starts time counting for Q2. Then, at time t _3, the continuous use time T1 Q1 is (in the example, 128 minutes) the level of incidence surveillance area has reached. At this point, the processing unit outputs a start signal to the temporary appropriate continuous continuous use time condition calculating unit so that the temporary appropriate continuous use time condition calculating unit outputs a temporary setting signal to the appropriate continuous use time setting changing unit. At the same time, the continuous use time state corresponding to the flow rate signal entering the appearance rate observation area during the operation of the second timer is stored. That is, blocking condition of continuous use time at time t ₃ is temporarily set to 720 minutes of L1 (stove there), and a second timer starts counting until the time to count up, the surveillance area It is determined in the same manner as described above whether or not data has been generated.
In this way, when the usage status of other gas appliances was observed, that is, when the existence of a gas appliance user was confirmed, even when the usage suddenly continued for a long time, when the gas level exceeded the monitoring level. Since it is temporarily set to have the L1 stove and starts data monitoring, it does not unnecessarily shut off the gas even when a person actually starts using it for a long time.

In Fig. 4, the gas stove combustion region (500-5000 (kcal /
The time cut-off condition of h)) was set to the case where the stove was initially set (the continuous use time condition was 160 minutes). The reason why the continuous use time condition of the combustion zone corresponding to having a gas stove is set to no stove as described above is that the gas stove is not used while the first timer 19 is operating. It is speculated that this is due to the fact. In addition, according to the contents such as Japanese Patent Application No. 63-298702,
It also applies when the appropriate continuous use time condition is changed from with stove (720 minutes) to without stove (160 minutes). It can be seen from the example of FIG. 4 that the present invention works effectively when the cutoff condition is set without the stove despite having the stove as described above.

The above contents can be easily realized by using the calculation and judgment functions by the program operation of the microcomputer or the like.

Effects of the Invention As described above, the gas cutoff device of the present invention has the following effects. (1) By constantly monitoring the gas usage state and comparing it with the set appropriate continuous use time condition, when the condition is deviated, that is, when an abnormality is determined, the shutoff means is activated to supply the gas. Since the operation is stopped, there is an effect that a dangerous state such as gas explosion or gas poisoning can be prevented in advance. Also, the start signal is used to observe the actual usage pattern of the gas supply system in which the gas meter is installed for a predetermined time of the first timer, and the observed data (for example, maximum value) is compared with an initial value to obtain a predetermined value. Is set as the appropriate continuous use time condition, so individual special conditions are taken into consideration in comparison with conditions that were uniformly determined by the combustion amount of the gas appliances and the capacity (number of gas meters) of the gas appliances Therefore, the safety level against a gas accident can be further increased.

Furthermore, after the first timer times out, the data monitoring area of the appearance rate observation area is set to constantly monitor the data,
When the second timer is activated and predetermined data is observed, the proper continuous use time condition is reset again. Here, the data monitoring area of the appearance rate observation area is set according to the appropriate continuous use time condition for each classification of the gas combustion amount range, and the data monitoring mode is entered through the usability of the gas appliance and the presence confirmation of the user. Even if you start using the stove from summer to winter, or if you suddenly start using the stove for a long time, it is possible to automatically change the appropriate continuous use time condition without causing unnecessary interruption.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a gas shutoff device according to an embodiment of the present invention, FIG. 2 is a diagram showing a relationship between a gas combustion amount and continuous use time in the gas shutoff device, and FIG. 3 is the gas shutoff device. FIG. 4 is a diagram showing a change with time in the proper continuous use time condition, FIG. 4 is a diagram showing a change in the gas combustion amount with time, and FIG. 5 is a functional block diagram of a conventional gas shutoff device. 15 ... Flow rate detection unit, 16 ... Flow rate calculation unit, 17 ... Initial condition storage unit, 18 ... Appropriate continuous use time determination unit, 19 ... First timer, 20 ... Activation signal application means, 21 ... … Continuous use time memory calculation unit, 22 …… Appropriate continuous use time setting change unit, 23
...... Blocking means, 24 ...... Appearance rate observation area setting section, 25 …… Second
Timer, 26 …… Temporary appropriate continuous use time condition calculation unit, 27
...... Flow rate change detection unit, 28 ...... Continuous use time storage processing unit in the appearance rate observation area, 29 …… Proper continuous use time condition temporary storage unit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Horii 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Ichitaka Asano 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Shinzo Kato 2-16-4 Tadao, Machida, Tokyo Metropolitan Gas Safety Association Liquefied Petroleum Gas Laboratory (72) Inventor Mitsuo Namba 2-16-4 Tadao, Machida, Tokyo High-pressure gas Liquefied petroleum gas research institute of the Japan Security Association (72) Inventor Reihei Uematsu 2-16-4 Tadao, Machida, Tokyo High-pressure gas

Claims (1)

[Claims] 1. A flow rate detecting section for emitting a signal according to a passing gas amount of a gas meter provided in a gas supply line, and a flow rate calculating section for calculating a gas flow rate by a flow rate signal sent from the flow rate detecting section. An initial condition storage unit that stores the continuous use time condition as an initial value in advance, and if the time during which the same flow rate signal obtained from the flow rate calculation unit continues deviates from the proper continuous use time condition, it is determined to be abnormal and a cutoff signal is given. An appropriate continuous use time determination unit that outputs the first predetermined time, a first timer that counts a first predetermined time, a start signal application unit that starts the first timer, and a signal from the flow rate calculation unit that outputs the first A continuous use time storage calculation unit that calculates a use time condition based on the continuous use time for each gas flow rate during the timer operation, and outputs a calculation result when the first timer operation ends; An appropriate continuous use time setting changing unit that compares the output of the calculation unit with the initial condition and changes the setting of a predetermined value as a new appropriate continuous use time condition, and a gas passage according to a cutoff signal from the appropriate continuous use time determination unit. After the proper continuation use time condition is set in accordance with the gas flow rate signal by the shutoff means for shutting off and the proper continuation use time setting change unit, the proper continuation use time is multiplied by the predetermined value to the changed proper use condition. Appearance rate observation area setting unit that sets a monitoring area for each condition, a second timer that counts a second predetermined time, and the appropriate continuous use time determination according to a predetermined flow rate signal obtained from the flow rate operation unit Input a signal from the flow rate calculation unit and a temporary suitability continuous use time condition calculation unit that outputs a temporary setting signal to the appropriate continuous use time setting change unit so as to apply the temporary appropriate continuous use time condition to the unit. A flow rate change detection unit for transmitting a signal when there is more flow change value,
It is determined whether or not the time from the start to the end of the flow rate of the predetermined gas has entered the appearance rate observation area set according to the predetermined flow rate signal, and at the time of the first entry, or the predetermined gas flow rate continues. After there is a signal from the flow rate change detection unit on the way, at the time when the continuous use time of the predetermined gas flow rate signal is included in the appearance rate observation area, a start signal is output to the second timer, A flow rate that outputs a start signal to the provisional proper continuous use time condition calculation unit so as to output a provisional setting signal to the proper continuous use time setting change unit and enters the appearance rate observation area during the second timer operation. Memorize the continuous use time state according to the signal, and further
When the stored continuous use time state is a predetermined number of times or more, the continuous use time storage processing unit of the appearance rate observation area for calculating the proper continuous use time condition, and the proper continuous use time condition temporary for storing the current proper continuous use time condition And a storage unit, wherein the appropriate continuous use time setting change unit sets the current appropriate continuous use time condition to the appropriate continuous use time condition temporary when the temporary setting signal from the temporary appropriate continuous use time condition calculating unit is input. After the temporary setting signal is stored in the storage unit and the setting of the temporary setting signal is changed as an appropriate continuous use time condition, the signal from the continuous use time storage processing unit of the appearance rate observation area at the end of the operation of the second timer, or the temporary Input the signal from the memory,
If the signal from the former is calculated to change the appropriate continuous use time condition, the signal is obtained. If the signal from the former is not calculated to change the appropriate continuous use time condition, the latter is obtained. A gas shutoff device that changes and sets the signal of as a condition for proper continuous use time.