JP4670238B2 - Gas shut-off device - Google Patents

Description

The present invention relates to a gas shut-off device that detects the flow rate of various media flowing in a pipe using ultrasonic waves, such as city gas and LP gas, and monitors whether the gas use state is safe based on the change in gas flow rate.

  This type of conventional gas cutoff device has a configuration as shown in the block diagram of FIG. 3 (see, for example, Patent Document 1).

  In FIG. 3, 1 is a flow path, 2 is an upstream vibrator, and is installed on the upstream side of the flow path 1 for transmitting and receiving ultrasonic waves. Reference numeral 3 denotes a downstream vibrator, which transmits and receives ultrasonic waves and is attached facing the downstream side of the flow path 1. Reference numeral 4 denotes a transmission circuit that transmits an ultrasonic signal to the upstream vibrator 2, and reference numeral 5 denotes an amplification circuit that amplifies the signal received by the downstream vibrator 3. A comparison circuit 6 compares the amplified signal with a reference signal. 7 is a time measuring means, which measures the time from the transmission of the ultrasonic wave to the reception by a timer counter. Reference numeral 8 denotes a measurement circuit including the transmission circuit 4 to the time measuring means 7. A flow rate calculating means 9 obtains a flow rate value in consideration of the size of the pipe line and the flow state according to the ultrasonic propagation time by the time measuring means 7. Reference numeral 10 denotes a cycle variable means for changing the measurement cycle according to the value of the flow rate calculation means 9. Reference numeral 11 denotes a measurement start means that adjusts the signal transmission timing to the transmission circuit in accordance with the value of the period variable means 10. Reference numeral 12 denotes measurement end means for detecting the end of calculation of the flow rate calculation means 9. Reference numeral 13 denotes voltage control means for lowering the voltage of the measurement circuit 8 in synchronization with the measurement end means 12 and returning the voltage of the measurement circuit 8 in synchronization with the start of measurement by the measurement start means 11.

Next, the operation of the conventional configuration will be described. In the flow path 1 through which the medium gas such as city gas or LP gas flows, a burst signal is transmitted from the transmission circuit 4 by the measurement start means 11, and the ultrasonic signal transmitted from the upstream vibrator 2 flows in the flow path 1. , And is received by the downstream vibrator 3 and further processed by the amplifier circuit 5 and the comparison circuit 6, and the time from transmission to reception is measured by the time measuring means 7. When the flow rate is large, it is necessary to reduce the error by increasing the time sampling, and when the flow rate is low or when the flow rate is zero, there is almost no error even if the measurement sampling is delayed. Therefore, the measurement interval is changed according to the value of the flow rate calculation means 9. The time interval variable means 10 with a small value of the flow rate calculation means 9 increases the measurement time interval, and as the value of the flow rate calculation means 9 increases, the measurement time interval decreases. Further, the voltage of the measuring circuit 8 is reduced between the measurements. When the flow rate measurement means 9 finishes the flow rate measurement, a signal is sent to the measurement end means 12 and the voltage control means 13 lowers the voltage or makes it zero. The voltage starter 11 restores the voltage of the measuring circuit 8 to the original state by the voltage controller 13 before starting the measurement.
Japanese Patent Laid-Open No. 9-21667

  However, the conventional configuration has the following problems. The flow rate in the flow path 1 is measured by the upstream vibrator 2 and the downstream vibrator 3, but when a device that varies the pressure on the upstream side is used, the flow velocity distribution in the flow path 1 changes in pressure. Unlike the case where there is no gas flow, especially in the case of gas appliances with a low flow rate such as a gas table, if the flow velocity distribution is not stable and the pressure fluctuation is large, a negative instantaneous flow rate may be detected temporarily, or if the appliance is stopped In some cases, the flow rate value to be detected detects a negative instantaneous flow rate due to pressure fluctuations, but an integration determination method in such a case is not disclosed.

  The present invention solves the above-described conventional problems, and provides a gas shut-off device that accurately and accurately accumulates the amount of gas used regardless of whether or not the gas appliance is used, even if the usage flow rate of the appliance used varies. It is intended.

In order to solve the conventional problems, the present invention includes a flow rate detection unit that measures a signal propagation time in a medium and detects a flow rate, a flow rate calculation unit that converts a flow rate from the flow rate detected by the flow rate detection unit, Integration buffer means for performing integration correction based on the flow rate value of the flow rate calculation means, integration table means having a table in which the measured flow area is divided into a plurality of areas and an integration cycle is set for each flow area, and predetermined integration by the integration buffer means When the value reaches the value, the addition integrated amount calculating means for calculating the integration cycle of the unit integrated amount from the flow rate value obtained by the flow rate calculating means and the integration table means, and outputting the unit integrated amount every predetermined time, and the unit integrated amount And a display means for displaying the integrated value and the like.

Even if a device that causes pressure fluctuation is connected on the upstream side and a low-flow device such as a gas table or a gas fan heater or a large-flow device such as GHP or a water heater is connected on the downstream side. Depending on the detected instantaneous flow rate , the integration buffer means determines whether to add to the positive side or to adjust to the negative side, performs integration, and when the predetermined integrated value is integrated, the time corresponding to the flow rate stopped by the flow rate detection means Since the unit integrated amount is output to the integrating means every time, the integrated value increases according to the amount of use of the appliance, especially when displaying the integrated value on the display means, it is increased according to the amount of usage of the appliance, Since the change state can be accurately displayed according to the actual usage, the integrated value can be obtained and displayed accurately and accurately regardless of whether the flow rate fluctuates or instruments having different flow rates are used.

According to the gas shut-off device of the present invention, a device for changing the pressure on the upstream side is connected, and a low flow rate device such as a gas table or a gas fan heater on the downstream side, or a large flow rate device such as a GHP or a water heater. Even if is connected, depending on the detected instantaneous flow rate , the integration buffer means determines whether to add to the positive side or to adjust to the negative side, and integration is performed. Depending on the flow rate, the corresponding integration cycle is obtained from the integration table means, and the unit integration amount is output to the integration means every predetermined time. Therefore, the integration value increases according to the usage amount of the appliance, and in particular, the integration value is displayed. The display can be increased according to the amount of equipment used, and the change state can be accurately displayed according to the actual usage, so even if equipment with different flow rates is used, According to usage Accumulation cycle can be obtained at high speed without the problem that it cannot be displayed at a high speed, especially in the case of battery power, battery consumption is low, and the accumulated value can be obtained and displayed accurately and accurately when using gas appliances. This has the effect of greatly improving reliability.

According to a first aspect of the present invention, flow rate detection means for measuring a signal propagation time in a medium and detecting a flow rate, flow rate calculation means for converting the flow rate from the flow rate detected by the flow rate detection means, and a flow rate value of the flow rate calculation means Integration buffer means for performing integration correction, integration table means having a table in which a plurality of measured flow areas are divided and an integration cycle is set for each flow area, and when the integrated buffer means reaches a predetermined integrated value, the flow calculation means An addition integration amount calculation means for calculating an integration cycle of the unit integration amount from the flow rate value obtained in step 1 and the integration table means, and outputting the unit integration amount every predetermined time; an integration means for adding the unit integration amount; And display means for displaying values and the like.

A gas heat pump type air conditioner (GHP) and other appliances that tend to cause pressure fluctuations are connected to the upstream side where the gas shut-off device is installed, and low-flow devices such as a gas table and a gas fan heater, GHP and hot water supply are connected to the downstream side. When a large flow rate device such as a vacuum vessel is connected, the flow rate of the device is obtained by the flow rate detection means and the flow rate is converted.However, there are times when the instantaneous flow rate changes due to pressure fluctuation etc. and positive and negative flow rates are detected. It is determined whether it is positive or negative, and is once offset and integrated by the plus / minus value in the integration buffer means , and when the predetermined amount is integrated, it is output to the addition integrated amount calculation means, and the flow rate from the integration table means corresponds to the flow rate from the current instrument usage flow rate, and It gets the integration cycle for outputting the unit integration quantity, because by accumulating the unit integrated amount regularly integrating means, in particular a battery can be obtained integration cycle at high speed In the case of the power source, the battery consumption is small, and it can be accurately integrated with the increment of the integrated value according to the flow rate used by the instrument, and can be displayed. It is possible to display accurately without increasing the display.

According to a second aspect of the present invention, flow rate detection means for measuring a signal propagation time in a medium and detecting a flow rate, flow rate calculation means for converting a flow rate from the flow rate detected by the flow rate detection means, and a flow rate value of the flow rate calculation means An integration buffer means for performing an integration correction, and when a predetermined integrated value is reached by the integration buffer means , an integration cycle of a unit integrated amount is calculated from the predetermined integrated value and the flow rate value obtained by the flow rate calculating means, and every predetermined time. An addition integrated amount calculating means for outputting a unit integrated amount; an addition period limiting means for outputting a predetermined integral when the integration period of the unit integrated amount obtained by the additive amount integrating means is greater than or equal to a predetermined time; and It comprises an integrating means for adding the calculated unit integrated amount every predetermined time, and a display means for displaying the integrated value and the like.

A gas heat pump type air conditioner (GHP) and other appliances that tend to cause pressure fluctuations are connected to the upstream side where the gas shut-off device is installed, and low-flow devices such as a gas table and a gas fan heater, GHP and hot water supply are connected to the downstream side. When a large flow rate device such as a vacuum vessel is connected, the flow rate of the device is obtained by the flow rate detection means and the flow rate is converted.However, there are times when the instantaneous flow rate changes due to pressure fluctuation etc. and positive and negative flow rates are detected. Accumulation cycle for determining whether the value is positive or negative, and once offset and integrated by the integration buffer means , and when the predetermined amount is integrated, it is output to the addition integrated amount calculation means and outputs a further unit integrated amount of the predetermined flow rate from the current appliance usage flow rate Although determined by accumulating regularly units integrating the integrated unit amount, if integration cycle determined quite long, pressurized to the integrating means at a fixed period is a sum period time limit It can be integrated accurately with an increment of the integrated value according to the flow rate of normal equipment, can be displayed, and is integrated every certain time even when a low flow rate flows, so it is integrated from the communication means Even if a value is requested, the integrated value can be known at an early stage, and can be accurately displayed without being integrated or displayed at a fixed amount regardless of the flow rate of the instrument, or displayed as an integrated increase that does not match the actual situation.

  The third invention is a program for causing a computer to execute all or part of the procedure of the gas shut-off device according to the first or second invention. Since this is a program, the gas shut-off of the present invention is performed using a general-purpose computer or server. Part or all of the apparatus can be easily realized. Also, program distribution and installation can be simplified by recording on a recording medium or distributing a program using a communication line.

  Hereinafter, first and second embodiments of the present invention will be described with reference to FIG. 1 and FIG. 1 and 2, the same reference numerals are given to components having the same functions as those in FIG. 3. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a block diagram of a gas shut-off device according to a first embodiment of the present invention. Reference numeral 14 denotes a flow velocity detection means, an upstream vibrator 2 disposed opposite to a flow path 1 of a gas medium such as LP, and a downstream side. An ultrasonic signal is transmitted from one to the other between the transducers 3 and the flow velocity of the gas used is detected from the propagation time. An example of the flow velocity detection means 14 is as follows. That is, the flow velocity detection unit 14 includes a switching unit 15, a transmission unit 16, a reception unit 17, a repetition unit 18, and a propagation time measurement unit 19.

The transmission means 16 and the reception means 17 are connected to the switching means 15. The switching means 15 first connects the transmission means 16 to the upstream vibrator 2, the reception means 17 to the downstream vibrator 3, and then the transmission means 16. The connection destinations of the transmission means 16 and the reception means 17 are alternately switched such that the transmission means 16 is connected to the downstream vibrator 3 and the reception means 17 is connected to the upstream vibration element 2. When the switching means 15 connects the receiving means 17 to the upstream vibrator 2 and the transmitting means 16 to the downstream vibrator 3, the repeating means 18 transmits the ultrasonic signal transmitted from the transmitting means 16 to the upstream vibration. The signal is received by the receiving means 17 from the downstream vibrator 3 through the flow path 1 from the child 2, but the transmission from the ultrasonic signal to the reception is repeated, and the signal propagation time is measured by the propagation time measuring means 19. Repeat the operation. The propagation time measuring means 19 measures and accumulates the time from transmission to reception of the ultrasonic signal. Next, the receiving means 17 is connected to the downstream vibrator 3 and the transmitting means 16 is connected to the upstream vibrator 2 by the switching means 15, and the above operation is repeated. The propagation time measuring means 19 obtains a propagation time difference from the propagation time first received and obtained and the signal propagation time measured after being switched by the switching means 15 next.

Reference numeral 20 denotes a flow rate calculation means for obtaining a flow velocity from the obtained propagation time and further converting it to a flow rate value. The integration buffer means 21 integrates the flow rate values obtained by the flow rate calculation means 20 every predetermined time. When the obtained instantaneous flow rate is positive, it is added, but when it is a negative flow rate, subtraction processing is performed and offset processing is performed. In particular, when an instrument that causes pressure fluctuations such as GHP is used on the upstream side, the gas shut-off device on the downstream side has a flow rate value that is as if the instrument was used when the instrument is not used on the downstream side. Even if a negative flow rate is detected, the integrated amount is prevented from increasing arbitrarily.

Reference numeral 22 denotes an integration table means, which divides the measured flow area into a plurality of parts and has, as a table, integration periods of unit integrated amounts to be integrated for each flow area. Reference numeral 23 denotes an addition integrated amount calculation means, which performs an offset process from the flow rate obtained by the integration buffer means 21 and integrates it as an integrated value when it reaches a predetermined amount. However, there is a problem that the display is not increased in order. Therefore, when a predetermined amount is integrated in the integration buffer means 21, an integration cycle for each unit integration amount is obtained from the integration table means 22 from the instantaneous flow rate at that time. Then, a unit integrated amount is output for each obtained integration cycle. When the unit integrated amount reaches a predetermined number of times, the predetermined amount is reached. Reference numeral 24 denotes an integration means for adding unit integration amounts output at each integration cycle determined by the addition integration amount calculation means 23. Reference numeral 25 denotes a display means for displaying the integrated value integrated by the integrating means 24 and the like.

  Numeral 26 is an abnormality determination means for dividing an abnormal flow value such as hose disconnection and a flow range that can be used by the gas shut-off device, and having a use time set value corresponding to each flow range and distinguishing from a normal use time of the gas appliance. A determination time is stored, and the flow rate value obtained by the flow rate calculation means 20 is compared with the set abnormality determination value when using the gas appliance to determine whether or not it is in an abnormal use state. For example, when the connecting hose to the appliance such as the stove is accidentally disconnected, an abnormal flow rate flows, but the determined flow rate value and the abnormality determination value are compared by the abnormality determination means 26 to determine whether or not there is an abnormality. Alternatively, a usage time cut-off table that defines a usage time limit corresponding to when the appliance such as a stove is used much longer than the normal usage time is stored, and the abnormality determination means 26 is a flow rate calculation means. The flow value obtained at 20 is monitored.

  Reference numeral 27 denotes a blocking means, which outputs a blocking signal when the abnormality determining means 26 determines that an abnormality has occurred, and blocks the gas flow path 1. When the abnormality determining means 26 determines that the gas use state is abnormal and the shut-off means 27 is driven, the shut-off state and the content of the shut-off are displayed on a liquid crystal display element or the like of the notifying means (not shown) and gas safety is monitored. Report to the center using a telephone line.

  Next, the operation of the above configuration will be described. Usually, it connects with a pressure regulator with a high-pressure hose from an LPG container, and a gas shut-off device is installed downstream from the gas consuming appliance. The fluid flow path 1 of the gas shut-off device is a part of a long pipe. Among these, the upstream vibrator 2 and the downstream vibrator 3 are installed obliquely to measure the flow rate by propagation of ultrasonic waves. On the other hand, the flow path 1 branches from the upstream side of the gas shut-off device and is connected to a gas heat pump air conditioner (GHP) or the like. After stopping the use of gas appliances, there is no flow of gas in the pipe from upstream to downstream, but if GHP or the like is operated on the upstream side, the gas pressure fluctuates, as if the appliance is being used. The flow rate may be detected or a negative flow rate may be detected.

Here, an example of the operation of the flow velocity detection means 14 will be described. In the flow path (gas pipe) 1, an ultrasonic signal is transmitted and received between the upstream transducer 2 and the downstream transducer 3 installed obliquely. The transmission means 16 is connected to the upstream vibrator 2 by the switching means 15, while the downstream vibrator 3 is connected to the reception means 17, and the signal transmitted from the transmission means 16 is transmitted from the upstream vibrator 2 to the downstream vibrator. 3 is received. A single-around system in which this operation is performed the number of times set by the repeating means 18 is configured. The propagation time until the reception means 17 receives the ultrasonic signal emitted from the transmission means 16 is accumulated, and the propagation time measurement means 19 obtains the time.

  Next, the switching means 15 connects the transmitting means 16 to the downstream vibrator 3 and connects the receiving means 17 to the upstream vibrator 2. An ultrasonic signal is output from the transmitting means 16 and received by the receiving means 17 connected to the upstream vibrator 2 via the flow path 1 via the downstream vibrator 3. As described above, the number of times set by the repeating means 18 is performed. The propagation time until the reception means 17 receives the ultrasonic signal emitted from the transmission means 16 is accumulated by the propagation time measurement means 19, and further the propagation time when the ultrasonic signal is emitted from upstream to downstream, and the downstream The difference in propagation time is obtained from the propagation time when fired upstream from. The propagation time obtained by the propagation time measuring means 19 in the flow rate computing means 20 is converted into a flow velocity value V and then converted into a flow value Q. In FIG. 1, A indicates the direction in which the gas medium flows.

Next, the flow rate value obtained by the flow rate calculation means 20 is integrated in the integration buffer means 21. At this time, addition integration is performed in the case of a positive flow rate, but subtraction processing is performed from the integration value stored in the current integration buffer means 21 in the case of a negative flow rate. Thus, when the flow rate change due to pressure fluctuation is detected on the upstream side, the actual usage amount of the appliance is obtained while canceling out. While the fluctuation is offset, the integrated value does not increase. However, the integrated value increases when the instrument starts to be used, and when it reaches a predetermined amount, preparation for storage in the integrating means 24 is made. That is, when the predetermined amount is accumulated, the addition integration amount calculation means 23 obtains the integration cycle of the unit integration amount held by the integration table means 22 from the instantaneous flow rate detected by the flow rate calculation means 20 at that time. Then, a unit integrated amount is output at the determined integration cycle, and the integrating means 24 integrates and stores each unit integrated amount, and when the integrated value is added for each unit integrated amount by the display means 25, it is displayed when the minimum display value is reached. In addition, the integrated value is displayed.

  Next, the abnormality determination means 26 determines whether the obtained flow rate is in an abnormal use state of the appliance. The abnormality determination means 26 divides the flow rate that can be distinguished from the maximum flow rate that can be used in the gas shut-off device and the abnormally large flow rate due to hose disconnection and the flow rate range that can be used in the gas shut-off device, and corresponds to each flow rate range. It has a usage time setting value. The abnormality determination unit 26 compares the flow rate obtained by the flow rate calculation unit 20 with the set abnormality determination flow rate to determine whether or not the flow rate has been exceeded. Compare with the value to determine whether it is in an abnormal long-time use state. For example, a use time cut-off table that defines a time limit for use time corresponding to a case where a device such as a stove is used much longer than the maximum use time for normal use is stored in the abnormality determination means 26. Monitors instrument flow. When the abnormality determining means 26 determines that an abnormality has occurred, a cutoff signal is output to the cutoff means 27 and the gas flow path 1 is blocked. When the abnormality determining means 26 determines that the gas use state is abnormal and the shut-off means 27 is driven, the shut-off state and the shut-off content are displayed on the liquid crystal display element of the display means 25 and the safety monitoring of the gas is performed. Report via phone line.

Thus, when the gas shut-off device is installed and the flow rate in the flow path 1 is measured, even if there is a change in flow rate due to the flow rate of the appliance, the integration cycle corresponding to the appliance usage flow rate per unit integration amount for each predetermined amount is faster than the integration table. Therefore, it is possible to integrate and display according to the flow rate of the equipment used, eliminate the feeling of discomfort due to the constant display regardless of the flow rate, and accurately use the equipment without accumulating it independently. Integration and integration display linked to actual changes is possible, and integration cycle can be calculated at high speed. Battery power consumption is low especially in the case of battery power, and changes in appliance usage are monitored from the integrated value through the security center. It is also possible to accurately grasp the state of gas use, improving usability.

(Embodiment 2)
FIG. 2 is a block diagram of a gas shutoff device according to a second embodiment of the present invention. In FIG.
Components having the same functions as those in FIG. 1 and FIG.

  In FIG. 2, reference numeral 28 denotes an addition cycle limiting means. When the integration cycle obtained by the addition integration amount calculation means 23 is equal to or longer than a predetermined time, the integration cycle is limited to a certain fixed time, and the instrument is set to be too long. It prevents taking a long time after the use is stopped.

Next, the operation of the above configuration will be described. The method for obtaining a predetermined integrated value by the integrating buffer means 21 is the same as that in the first embodiment, and will be omitted.

Here, when the predetermined amount is integrated, the addition integrated amount calculating means 23 calculates the time during which the unit integrated amount that becomes the predetermined amount flows by integrating the predetermined number of times from the instantaneous flow rate detected by the flow rate calculating means 20 at that time. Then , the unit integrated amount is output using the obtained time as an integration cycle. The addition cycle limiting means 28 determines whether or not it is equal to or longer than a predetermined cycle. If it is equal to or shorter than the predetermined cycle, the output is output. . However, when the flow rate is abnormally small, if the cycle is considerably longer than the predetermined time, the integration cycle is fixed at a certain time and output every time. In other words, if the time is too long in the calculation, even if the appliance is stopped, it will be counted every minute unit accumulated amount for a long time, so there is a slight difference when looking at the integrated amount by communication etc. To prevent such unrealistic behavior. When the integrated value is added for each unit integrated amount by the display means 25, when the minimum display value is reached, the integrated value is displayed.

In this way, when the flow rate in the flow path 1 is measured when the gas shut-off device is installed, even if there is a change in flow rate, an integration cycle corresponding to the appliance usage flow rate is obtained and integrated for each predetermined amount and for each unit integrated amount. Can be integrated and displayed according to the flow rate used, especially when a very small flow rate flows, such as immediately after the instrument is stopped. It is possible to display integration and total display that is linked to changes in the actual usage of the equipment, without being unnecessarily accumulated independently, and to change the usage of the equipment through the security center. Can be monitored from the integrated value, the gas usage state can be accurately grasped, and the usability is improved.

  As described above, the gas shut-off device according to the present invention is a water meter that measures various media flowing in the pipe using ultrasonic waves, for example, a liquid such as water, and an electric power that measures the amount of electricity and integrates the amount used. Applicable to applications such as totals.

FIG. 1 is a control block diagram of the gas cutoff device according to the first embodiment of the present invention. FIG. 3 is a control block diagram of a gas shut-off device according to a second embodiment of the present invention. Control block diagram of a conventional gas shut-off device

DESCRIPTION OF SYMBOLS 14 Flow velocity detection means 20 Flow rate calculation means 21 Integration buffer means 22 Integration table means 23 Addition integration amount calculation means 24 Integration means 25 Display means 26 Abnormality determination means 27 Blocking means 28 Addition period restriction means

Claims (2)

A flow rate detection means for measuring a signal propagation time in the medium and detecting a flow rate; a flow rate calculation means for converting the flow rate detected by the flow rate detection means into an instantaneous flow rate; and the instantaneous flow rate obtained by the flow rate calculation means is a positive flow rate. In the case of a negative flow rate, an integration buffer means for performing a subtraction process, an integration table means having a table in which a measured flow area is divided into a plurality of parts and an integration cycle is set for each flow area, and the integration buffer means in predetermined integrated value reaches a obtains the integration period of the flow rate computing means determined meth instantaneous flow rate and the integrated table means from a unit integrated amount, adding the integrated amount computing means for outputting a unit integrated amount for each of the integration cycle And a gas shut-off device comprising: an integrating unit that adds the unit integrated amount; and a display unit that displays the integrated value and the like. When the flow rate detecting means for measuring the signal propagation time in the medium and detecting the flow rate, the flow rate calculating means for converting the flow rate from the flow rate detected by the flow rate detecting means, and the instantaneous flow rate obtained by the flow rate calculating means is a positive flow rate Is necessary to integrate a unit integrated amount that becomes a predetermined integrated value by integrating a predetermined number of times when a predetermined integrated value is reached by the integrating buffer unit, and when the integrated buffer unit reaches a predetermined integrated value. calculates the a time from the instantaneous flow rate and which has been determined by the flow rate computing means and the unit integrated amount, as integration cycle this time, the addition accumulated amount calculating means for outputting a unit integrated amount for each of the integration cycle, the addition amount When the integration cycle of the unit integration amount obtained by the integration unit is greater than or equal to a predetermined time, an addition cycle limiting unit that fixes the integration cycle to a certain time, an integration unit that adds the unit integration amount, and an integrated value are displayed. Gas cutoff apparatus and a display unit that.