JP2003279039A - Gas cutoff system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously use a gas appliance without cutting off a gas cutoff valve when the gas appliance is continuously used to a limit time on the basis of user's intention. <P>SOLUTION: The gas cutoff valve 11 and a flow sensor 12 are mounted on a fuel gas supply passage. A man sensor 4 for detecting the presence or absence of a man is mounted near the gas appliance in a house demanding a fuel gas. A safety control device 10 monitors a flow rate of the fuel gas detected by the flow sensor 12, and measures a time of the continuation of a condition that a flow of the fuel gas passed through the supply passage is kept within a specified flow range. Further the safety control device 10 cuts off the gas cutoff valve 11 at the expiration of the limit time, when the man sensor 4 does not detect the man in a period before the measured time reaches the limit time for limiting the use of the fuel gas, in a specified detection period before the expiration of the limit time, and extends the limit time when the man sensor 4 detects the man in the detection period. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas shut-off system which mainly controls opening and closing of a gas shut-off valve provided in a gas meter so as to protect a gas user's device from forgetting to turn it off.

[0002]

2. Description of the Related Art In recent years, a gas meter installed in a consumer of a fuel gas such as city gas has a microcomputer (hereinafter abbreviated as "microcomputer") built therein, and various safety functions are realized by the microcomputer. ing. This type of safety function includes a long-time shut-off function that automatically shuts off the gas shut-off valve built into the gas meter if the fuel gas transit time becomes abnormally long due to forgetting to turn off the gas-using device. . That is, in the long-time shutoff function, the gas shutoff valve is shutoff when the time when the state where the flow rate passing through the gas meter is within the prescribed flow rate range continues is measured, and when the measured time reaches the prescribed time limit. In the long-time shutoff function, the time limit for shutting off is preset according to the flow rate of the fuel gas. For example, for the flow rate corresponding to the use of the bathtub, the time limit is set to 110.
It is set to about a minute.

[0003]

By the way, in the long-time cutoff function, the limit time until the cutoff is fixed according to the flow rate as described above. Depending on the usage situation, the gas cutoff valve may be shut off when the time limit is reached even though it is not an abnormality such as forgetting to turn it off. On the other hand, a gas-using device such as a floor heating device may be operated all day long, and in this kind of gas-using device, the user tries to continue operating the gas-using device. When the time limit is reached, the gas shutoff valve may shut off automatically. In such a situation, in order to operate the gas using device again, the gas shutoff valve must be opened by operating the return button of the gas meter, and then the operation of the gas using device must be started. The problem of damage arises.

The present invention has been made in view of the above circumstances, and an object thereof is to use a gas-using device with the user's intention even if a period of time of a flow rate within a prescribed flow range reaches a prescribed time limit. It is to provide a gas shut-off system that enhances convenience while ensuring safety by enabling continued use of gas-using equipment without shutting off the gas shut-off valve when it can be determined that .

[0005]

According to a first aspect of the present invention, there is provided a gas shutoff valve arranged in a fuel gas supply passage, and a human presence detecting a presence or absence of a person near a gas-using device in a fuel gas consumer. The sensor and the flow rate of the fuel gas that passes through the supply passage are in a specified flow rate range.The time is measured and the measured time is the period until it reaches the time limit that limits the use of fuel gas. A safety control device that shuts off the gas cutoff valve when the time limit expires when the human sensor does not detect a person within the specified detection period before the expiration of
The safety control device is characterized in that the time limit is extended when the motion sensor detects a person within the detection period.

According to a second aspect of the present invention, in the first aspect of the present invention, an alarm is provided which has a detection means for detecting the presence or absence of an abnormality in the room when the fuel gas is used, and an informing means for giving a notice when the detection means detects an abnormality. A device is arranged in the vicinity of the gas-using device, and in the safety control device, when a human sensor detects a person during the detection period, a warning is issued through a notification device of an alarm device when the time limit expires. And

According to the third aspect of the present invention, a gas cutoff valve disposed in the fuel gas supply passage, a safety control device for monitoring the flow rate of the fuel gas passing through the supply passage and controlling the opening and closing of the gas cutoff valve, In a fuel gas consumer, a human sensor for detecting the presence or absence of a person near a gas-using device, a safety control device, and a communication device interposed between the human sensor and the network and capable of bidirectional data communication through the network. And a center device that is connected to a network and performs data communication with a safety control device and a human sensor through a communication device. In the safety control device, the flow rate of the fuel gas passing through the supply path is within a specified flow rate range. Is the period until the time that reaches the time limit for limiting the use of fuel gas is measured and the time measured is the prescribed detection period before the expiration of the time limit. In this case, the center device is notified, and when the safety control device notifies the detection period, the center device starts monitoring the presence or absence of a person detected by the motion sensor, and the motion sensor detects the person within the detection period. If not, the safety control device is instructed to shut off the gas cutoff valve when the time limit expires, and the time limit is extended when the motion sensor detects a person within the detection period.

According to a fourth aspect of the present invention, in the invention of the third aspect, an alarm is provided which has a detection means for detecting the presence or absence of an abnormality in the room when the fuel gas is used, and an informing means for giving an alarm when the abnormality is detected by the detection means. A detector is arranged in the vicinity of the gas-using device, and when the human detection sensor detects a person in the detection period, the center device gives a notice through an alarm device when the time limit expires. To do.

According to a fifth aspect of the invention, in the third or fourth aspect of the invention, the center device monitors the presence or absence of a person detected by the human sensor after the gas shutoff valve is shut off, and shuts off the gas. When the human sensor detects a person while the valve is shut off, the safety control device is instructed to open the gas shutoff valve.

According to a sixth aspect of the invention, in the third or fourth aspect of the invention, the center device monitors the presence or absence of a person detected by the human sensor after the gas shutoff valve is shut off, and shuts off the gas. When a person is detected by the motion sensor while the valve is shut off, the safety controller is instructed to open the gas shutoff valve after notifying the customer of the opening of the gas shutoff valve. Characterize.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) As shown in FIG. 1, a gas meter 1 used in this embodiment is a gas inserted into a supply path for supplying a fuel gas such as city gas to a gas using device 2. The shutoff valve 11 and a flow rate sensor 12 that measures the flow rate of the fuel gas that has passed through the gas shutoff valve 11 are provided. The flow rate detected by the flow rate sensor 12 is input to the safety control device 10 incorporated in the gas meter 1, and the safety control device 10 controls opening / closing of the gas cutoff valve 11 by an operation described later.
The safety control device 10 has a microcomputer as a main component and realizes various security functions. However, in the present embodiment, description will be made focusing on the long-time interruption function described as the conventional configuration among the security functions.

The safety control device 10 is capable of data transmission with the alarm device 3 arranged in the vicinity of the gas using device 2 via the transmission line L1. A wireless transmission line is used for at least a part of the transmission line L1. The alarm device 3 has a built-in gas sensor (not shown) as a detection means, and when it detects that gas is leaking as in the case where a flame is extinguished in a gas using device 2 such as a gas range, an alarm sound or a voice is given through the notification means 31. It is configured to provide acoustic notification such as a message. That is, the alarm device 3 is arranged in a room such as a kitchen in which the gas using device 2 is installed. Further, the alarm device 3 of this embodiment incorporates not only the gas sensor but also the human sensor 4. Since the alarm device 3 is arranged near the gas using device 2, the human sensor 4 is also arranged near the gas using device 2. The human sensor 4 may be either a passive type that uses a pyroelectric element that detects heat rays emitted from the human body, or an active type that performs projection / reception of infrared rays or transmission / reception of ultrasonic waves. .

The safety control device 10 operates as shown in FIG. The safety control device 10 detects the flow rate of the fuel gas passing through the supply passage by the output of the flow rate sensor 12,
When the flow rate sensor 12 detects a flow rate within the flow rate range defined as the gas-using device 2 is in use (S1), the following operation is performed. Here, the flow rate range determined to be in use of the gas using device 2 is divided into a plurality of stages according to the type and use state of the gas using device 2 (S2). By the way, when the flow rate is detected by the flow rate sensor 12, time measurement of the time when the flow rate is continuously detected is started (S
3). The time limit is set for each stage of the flow rate range, and for gas-using equipment 2 such as a floor heating device that is continuously used for a relatively long time, the time limit is set relatively long. The time limit is set to be relatively short for the gas using device 2 such as a bathtub in which the time for continuous use is relatively short. The flow rate sensor 12 continues to detect the flow rate even after the time limit time is started (S4). When the flow rate sensor 12 no longer detects the flow rate before the time limit is reached, the use of the gas-using device 2 ends. It is determined that the flow rate is to be waited until the next flow rate is detected (S
1).

By the way, the detection period is defined before the expiration of the time limit (S5), and it is determined whether or not the human sensor 4 detects a person within the detection period (S6). The detection period is a period of about 10 to 20 minutes before the expiration of the time limit, and if the time limit is about 100 minutes, when a person is detected by the motion sensor 4 within the detection period, gas usage is performed. It can be determined that there is a high possibility that the device 2 is intentionally used. Conversely, if no person is detected by the human sensor 4 within the detection period, it is determined that there is a high possibility that the gas-using device 2 will be forgotten to be turned off, and the gas shutoff valve 11 is shut off when the time limit expires (S9). Yes (S8).

When a person is detected by the human sensor 4 within the detection period (S6), first, a notification is sent for confirmation (S9). For this notification, the notification means 31 provided in the alarm device 3 is used to make an acoustic notification by an alarm sound or a voice message. For example, for a voice message,
Calling the user's attention with the message "Do you continue to use gas for a long time?" At this stage, if the user notices that he has forgotten to extinguish the gas, the user can extinguish the gas-using device. Further, since there is a high possibility that the gas using device 2 is intentionally used at the time of notification, the gas shutoff valve 11 is maintained in the open state by extending the time limit (S10).

To extend the time limit, the time limit set in a timer (not shown) provided in the safety control device 10 for measuring the period during which the flow rate is detected is equal to the preset time extension. Alternatively, the timer may be reset to restart the counting of the period during which the flow rate is detected.

In the above-described embodiment, when the human body sensor 4 detects a person during the detection period, the alarm device 3 gives an acoustic notification and extends the time limit. However, step S9 in FIG. It is also possible to adopt the configuration for performing only the notification shown as, or the configuration for performing only the extension of the time limit shown as step S10 in FIG.

It should be noted that the human sensor 4 can be incorporated not only in the alarm device 3 but also in other devices related to the gas-using device 2, for example, to operate a water heater or a floor heating device.
It is possible to incorporate the motion sensor 4 in a remote control device installed on a wall surface in a room for instructing stop or setting a temperature. In this case, the remote control device incorporates the notification means 31. Also, as shown by the chain double-dashed line in FIG.
The human sensor 4 does not necessarily have to be built in the alarm device 3, and the human sensor 4 may be connected to the alarm device 3 via the signal line L2. With this configuration, since the human sensor 4 can be installed without being restricted by the installation location of the alarm device 3, the human sensor 4 can be installed according to the installation location of the gas-using device 2.
Can be arranged at a more appropriate position. Also,
In this embodiment, a gas sensor is used as an alarm device 3 as a detection means for detecting the presence / absence of abnormality in the room when the fuel gas is used.
However, other detection means such as a fire sensor may be provided in the alarm device 3.

(Embodiment 2) By the way, when the gas cutoff valve 11 is shut off after a lapse of the time limit, the reset button of the gas meter 1 must be manually operated in order to open the gas shutoff valve 11. It is troublesome to go outside due to the manual operation of the return button of 1. On the other hand, in the recent gas-using device 2, since the solenoid valve provided inside the gas-using device 2 is shut off when the supply of gas is stopped, the gas shut-off valve 11 is shut off by the long-time shut-off function. Even if the gas cutoff valve 11 is opened again at this time, the fuel gas does not leak from the gas using device 2. Therefore,
When the gas shutoff valve 11 is shut off by the long-time shutoff function, if the presence of a person in the vicinity of the gas using device 2 is confirmed, there is no security problem even if the gas shutoff valve 11 is automatically returned. I can say. However, since the gas meter 1 uses a microcomputer which is relatively inexpensive and has a low processing capability, the output of the human sensor 4 is used in addition to the already-provided security function to perform the recovery process of the gas cutoff valve 11. It is difficult to add the function to do.

Therefore, in the present embodiment, a communication device 6 such as an NCU (network control unit) is attached to the current gas meter 1 to connect a network NW such as a public network, and a human feeling including the above-mentioned restoration process is performed. Various processes based on the detection result of the sensor 4 are performed by the center device 5 connected to the gas meter 1 via the network NW. The communication device 6 has a transmission line L, at least a part of which is a wireless transmission line.
An alarm device 3 is also connected via 3. Here, the voice message notified from the alarm device 3 can be given from the center device 5 via the communication device 6, and the presence / absence of a person detected by the motion sensor 4 attached to the alarm device 3 is determined by the communication device 6 It is possible to monitor with the center device 5 via the. With such a configuration, the center apparatus 5 is configured to monitor the presence or absence of a person by the human sensor 4 and to instruct the shutoff valve 11 of the gas meter 1 to shut off / open. Therefore, the gas shutoff valve 11 is operated by the operation of the shutoff function for a long time.
When the person is detected by the human sensor 4 in a state in which is shut off, the gas shut-off valve 11 can be automatically returned, so that the user operates the gas shut-off valve 11 in the consumer. It becomes possible to open the gas cutoff valve 11 without being aware of it.

In the following, the process of extending the time limit according to the presence or absence of a person detected by the human sensor 4 and the human sensor 4 detecting the human after the gas shutoff valve 11 is shut off by the long shutoff function. A process of automatically opening the gas cutoff valve 11 when the above is performed will be described. That is, the safety control device 10 detects the flow rate of the fuel gas passing through the supply path by the output of the flow rate sensor 12, and as shown in FIG. 4, the flow rate within the flow rate range defined as the gas-using device 2 is in use. Is detected by the flow rate sensor 12 (S
1) Then, the flow rate range is divided into a plurality of stages (S2), the time limit is set according to the flow rate range, and time counting is started (S3). The flow rate sensor 12 continues to detect the flow rate even after the time limit time is started (S4). When the flow rate sensor 12 no longer detects the flow rate before the time limit is reached, the use of the gas-using device 2 ends. When it is determined that the flow rate is detected, the flow waits until the next flow rate is detected (S1).

On the other hand, the detection period is defined before the expiration of the time limit (S5), and when the detection period is started, the center device 5 is notified via the communication device 6 that the time limit is about to expire. Notify (S6). When notified of the start of the detection period, the center device 5 starts monitoring the output of the motion sensor 4 attached to the alarm device 3, and within the detection period, the motion sensor 4 is detected.
The center device 5 is notified of the presence or absence of detection of a person by (S)
7). When a person is detected by the human sensor 4 within the detection period, it is determined that there is a high possibility that the gas using device 2 is intentionally used. On the contrary, if no person is detected by the human sensor 4 within the detection period, it is determined that there is a high possibility of forgetting to turn off the gas using device 2, and when the time limit expires (S8), the gas shutoff valve 11 is shut off. Do (S
9). The fact that the gas shutoff valve 11 has been shut off is notified to the center device 5 via the communication device 6.

When a person is detected by the human sensor 4 within the detection period (S7), the center device 5 gives an instruction to the alarm device 3 to give an alarm sound or a voice message (S10). At this stage, if the user notices that he has forgotten to put out the gas, the user can extinguish the gas-using device. Further, since it is highly possible that the gas-using device 2 is intentionally used at the time of notification, the safety control device 1 is arranged so that the center device 5 extends the time limit.
The gas shutoff valve 11 is kept open by instructing 0 (S11).

By the way, since the shutoff of the gas shutoff valve 11 in step S9 is performed by the shutoff function for a long time, as described above, the gas shutoff valve 11 may be automatically opened in some cases. That is, the gas cutoff valve 11
When the prescribed waiting time elapses after the interruption of (S12), the presence / absence of a person is confirmed by the human sensor 4 (S13). Here, the waiting time until the presence / absence of a person is detected by the human sensor 4 after the gas shutoff valve 11 is shut off can be set appropriately, and may be set to, for example, 5 minutes. The standby time is set with a margin for the period until the gas using device 2 is automatically closed after the gas shutoff valve 11 is shut off. When a person is detected by the motion sensor 4, it means that there is a person in the vicinity of the gas-using device 2, and therefore the network N
Notify the presence of a person to the center device 5 via W (S1
4). In the center device 5, when the detection of a person by the human sensor 4 is notified after the gas shutoff valve 11 is shut off, a recovery process is performed.
That is, the center device 5 gives an instruction for opening the gas cutoff valve 11 to the safety control device 10 (S15). The safety control device 10 has a function of standing by for 2 minutes when the opening of the gas shutoff valve 11 is instructed (S16), and after waiting for 2 minutes, the gas shutoff valve 11 is opened (S17).

After the gas shut-off valve 11 is shut off by the long-time shut-off function by the above-described operation, the gas using device 2
Gas shutoff valve 1 when the presence of a person using a gas is confirmed
1 can be automatically opened and the convenience is improved by eliminating the troublesome operation of opening the gas shutoff valve 11 by manually operating the return button of the gas meter 1 after the gas shutoff valve 11 is shut off. Can be done.

In the above-mentioned operation, it is assumed that the gas-using device 2 is automatically closed when the supply of the fuel gas is stopped by shutting off the gas shut-off valve 11. There are some that do not automatically close even if the supply of is stopped. Therefore, such a gas using device 2
Assuming that the center device 5 is used, the center device 5 instructs the alarm device 3 to notify by a voice message during the standby for 2 minutes before opening the gas cutoff valve 11 by the instruction from the center device 5. However, the user of the gas using device 2 may be caused to perform the cap closing operation by this voice message. An example of this kind of voice message is "The meter is recovering. Please wait for 2 minutes before using gas." Further, instead of notifying the voice message through the alarm device 3, the same content may be notified to the customer by telephone. Even if the gas shutoff valve 11 is opened while the gas using device 2 is not closed, the gas meter 1 with a built-in microcomputer has a safety function to shut off the shutoff valve 11 when a large amount of fuel gas flows. Therefore, safety can be secured. Other configurations and operations are the same as those in the first embodiment, and thus the description thereof will be omitted. In the present embodiment, a public network is illustrated as the network NW, but it goes without saying that another network NW such as the Internet or an intranet may be used.

[0027]

According to the first aspect of the present invention, there is provided a gas cutoff valve disposed in a fuel gas supply path, a human sensor for detecting the presence or absence of a person in the vicinity of a gas using device in a fuel gas consumer, and a supply sensor. The flow rate of the fuel gas passing through the passage is the period during which the state where the flow rate of the fuel gas is within the specified flow rate range is continuously measured If the motion sensor does not detect a person within the specified detection period, it is equipped with a safety control device that shuts off the gas cutoff valve when the time limit expires. This is to extend the time limit, and even if the period of continuous use of fuel gas reaches the time limit, if the presence of a person is detected by the human sensor located near the gas using equipment, Intent It is determined that the gas-using device is still in use, and in this case, the gas shut-off valve is not shut off, and the time limit is extended so that the gas-using device can continue to be used. Convenience will be improved without stopping easily. In addition, if the human sensor does not detect a person within the detection period before the time limit, the gas shutoff valve is shut off by determining that the gas-using device has been forgotten to be turned off, so that safety can be ensured as in the conventional configuration. .

According to a second aspect of the present invention, in the first aspect of the present invention, an alarm is provided which has a detection means for detecting the presence or absence of an abnormality in the room when the fuel gas is in use, and an informing means for giving a notice when the detection means detects an abnormality. A device is disposed near the gas-using device, and in the safety control device, when the motion sensor detects a person during the detection period, a warning is issued through a notification device of an alarm device when the time limit expires. When the gas using device is continuously used for a long time of reaching the time limit, the user of the gas using device can confirm whether or not the gas using device has been forgotten to turn off by a warning message.

According to the invention of claim 3, a gas cutoff valve disposed in the fuel gas supply passage, a safety control device for monitoring the flow rate of the fuel gas passing through the supply passage and controlling the opening and closing of the gas cutoff valve, In a fuel gas consumer, a human sensor for detecting the presence or absence of a person near a gas-using device, a safety control device, and a communication device interposed between the human sensor and the network and capable of bidirectional data communication through the network. And a center device that is connected to a network and performs data communication with a safety control device and a human sensor through a communication device. In the safety control device, the flow rate of the fuel gas passing through the supply path is within a specified flow rate range. Is the period until the time that reaches the time limit for limiting the use of fuel gas is measured and the time measured is the prescribed detection period before the expiration of the time limit. In this case, the center device is notified, and when the safety control device notifies the detection period, the center device starts monitoring the presence or absence of a person detected by the motion sensor, and the motion sensor detects the person within the detection period. If not, the safety control device is instructed to shut off the gas cutoff valve when the time limit expires.If the motion sensor detects a person within the detection period, the time limit is extended and fuel gas is continuously supplied. Even if the period of use has reached the time limit, if the presence of a person is detected by the human sensor located near the gas-using device, it is determined that the user is using the gas-using device continuously. In this case, since the time limit is extended so that the gas-using device is continued to be used without shutting off the gas shut-off valve, the operation of the gas-using device is not inadvertently stopped, which is highly convenient. That. In addition, if the human sensor does not detect a person within the detection period before the time limit, the gas shutoff valve is shut off by determining that the gas-using device has been forgotten to be turned off, so that safety can be ensured as in the conventional configuration. . Further, since the center device performs the instruction of shutting off the gas shutoff valve and the monitoring of the human sensor, the data processing amount in the safety control device does not increase while achieving the high functionality, and it is incorporated in the gas meter. It can be realized by using a low-performance microcomputer.

According to a fourth aspect of the invention, in the invention of the third aspect, an alarm is provided which has a detection means for detecting the presence / absence of an abnormality in the room when the fuel gas is used, and an informing means for giving a notice when the detection means detects an abnormality. A device is arranged in the vicinity of the gas-using device, and in the center device, when the motion sensor detects a person during the detection period, a notification is issued through a notification device of an alarm device when the time limit expires. When the gas-using device is continuously used for a long time to reach the time limit, the user of the gas-using device can confirm whether the gas-using device can be forgotten by a warning message.

According to a fifth aspect of the present invention, in the third or fourth aspect of the invention, the center device monitors the presence or absence of a person detected by the human sensor after the gas shutoff valve is shut off, and shuts off the gas. When a human sensor detects a person while the valve is shut off, the safety control device is instructed to open the gas shutoff valve. The gas shutoff valve shuts off by using the gas-using device for a limited time. If
In a situation where it is considered safe to open the gas shutoff valve due to the presence of a person near the equipment using the gas, the center device will instruct the opening of the gas shutoff valve, so the user should be aware of the operation to open the gas shutoff valve. There is no need to do it manually and convenience is improved.

According to a sixth aspect of the invention, in the third or fourth aspect of the invention, the center device monitors the presence or absence of a person detected by the human sensor after the gas shutoff valve is shut off, and shuts off the gas. When a person is detected by the motion sensor while the valve is shut off, the safety controller is instructed to open the gas shutoff valve after notifying the customer of the opening of the gas shutoff valve. Yes, when the gas shutoff valve is shut off by using the gas shutoff device for a limited time, it is safe to open the gas shutoff valve due to the presence of a person near the gas shutoff device. Since the opening of the valve is instructed by the center device, the user does not need to intentionally perform the operation of opening the gas cutoff valve, which improves convenience. Moreover, before the gas shut-off valve is opened, the customer is notified that the gas shut-off valve will be opened. Therefore, even if the gas-used equipment does not have the function of automatically closing the fuel gas by shutting it off, It is possible to prompt the user to close the valve and secure the safety while instructing the center device to open the gas cutoff valve.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the above.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is an operation explanatory diagram of the above.

[Explanation of symbols]

1 gas meter 2 gas equipment 3 alarm 4 Human sensor 5 Center device 6 Communication device 10 Safety control device 11 Gas cutoff valve 12 Flow sensor 31 Notification means NW network

Continued front page    F term (reference) 3J071 AA02 BB14 EE02 EE06 EE23                       FF03                 3K068 AA01 DA01

Claims (6)

[Claims] 1. A gas cutoff valve arranged in a fuel gas supply path, a human sensor for detecting the presence or absence of a person in the vicinity of a gas-using device in a fuel gas consumer, and a fuel gas passing through the supply path. If the flow rate is within the specified flow rate range, the time is measured continuously, and the measured time is the period until it reaches the time limit for limiting the use of fuel gas, and within the specified detection period before the expiration of the time limit. When the motion sensor does not detect a person, it is equipped with a safety control device that shuts off the gas cutoff valve when the time limit expires.The safety control device is designed to extend the time limit when the motion sensor detects a person within the detection period. Characteristic gas shutoff system. 2. An alarm device provided with a detection means for detecting the presence or absence of an abnormality in a room when a fuel gas is used, and an informing means for giving an alarm when the detection means detects an abnormality, is arranged in the vicinity of the gas using equipment, 2. The gas shutoff system according to claim 1, wherein, in the safety control device, when the motion sensor detects a person during the detection period, a warning is issued through a notification means of an alarm device when the time limit expires. 3. A gas cutoff valve arranged in the fuel gas supply passage, a safety control device for monitoring the flow rate of the fuel gas passing through the supply passage and controlling the opening and closing of the gas cutoff valve, and a fuel gas consumer. Connected to a network, a motion sensor that detects the presence or absence of a person in the vicinity of a gas-using device, and a communication device that intervenes between the safety control device and the motion sensor and the network to enable bidirectional data communication through the network. The safety control device and the center device that performs data communication with the motion sensor through the communication device are provided, and in the safety control device, the state where the flow rate of the fuel gas passing through the supply path is within the specified flow rate range is continuous. When the measured time is the period until the time reaches the time limit for limiting the use of fuel gas and the specified detection period before the expiration of the time limit is reached, the center device The center device starts monitoring the presence or absence of a person detected by the motion sensor when the detection period is notified from the safety control device, and limits when the motion sensor does not detect the person within the detection period. A gas cutoff system characterized by instructing a safety control device to cut off the gas cutoff valve when the time expires, and extending the time limit when the human sensor detects a person within the detection period. 4. An alarm device provided with a detection means for detecting the presence or absence of an abnormality in the room when the fuel gas is used, and a notification means for giving an alarm when the detection means detects an abnormality, is arranged in the vicinity of the gas using equipment, 4. The gas shutoff system according to claim 3, wherein in the center device, when a human sensor is detected by the human detection sensor during the detection period, a warning is issued through a notification means of an alarm device when the time limit expires. 5. The center device monitors the presence / absence of a person detected by the human sensor after the gas shutoff valve is shut off, and detects the person detected by the human sensor while the gas shutoff valve is shut off. The gas shutoff system according to claim 3 or 4, wherein the safety shutoff device is instructed to open the gas shutoff valve. 6. The center device monitors the presence / absence of a person detected by the motion sensor after the gas cutoff valve is cut off, and detects that a person is detected by the motion sensor while the gas cutoff valve is closed. The gas shutoff system according to claim 3 or 4, wherein the safety control device is instructed to open the gas shutoff valve after making a notice to notify the customer of the opening of the gas shutoff valve.