JP2010181383A - Decision device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a decision device and method capable of preventing an increase in burden on an operation unit of microcomputer or the like when determining whether a gas apparatus is used. <P>SOLUTION: In the gas meter 40, a regular measurement mode executing part 43a measures flow rate once every approx. 2 seconds, while a simplified measurement mode executing part 43b measures variation in gas flow rate of not less than the prescribed value at intervals of once every approx. 0.1 seconds so as to infill the measurement intervals of once every approx. 2 seconds. Thus a high-speed measurement mode executing part 43c determines whether gas fittings 10 with governors, etc. are used from frequency and amplitude of the waveform obtained by acquiring electric signal from a pressure sensor 42, when variation in gas flow rate of not less than the prescribed value has been measured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a determination device and a determination method.

Conventionally, ultrasonic and thermal gas meters are known. In such a gas meter, the gas flow rate is measured once every about 2 seconds (see, for example, Patent Document 1 and Patent Document 2).
JP 2008-202948 A JP 2001-324368 A

  Here, the present applicant has invented the technique of Japanese Patent Application No. 2008-86022. In the present invention, it is determined based on the waveform of the gas pressure whether a gas appliance with a governor is used, a gas appliance without a governor is used, and whether a gas leak has occurred. In addition, there is a certain correlation between the gas pressure and the gas flow rate, whether a gas appliance with a governor was used, a gas appliance without a governor was used based on the gas flow rate, and whether a gas leak occurred It is also possible to judge.

  However, the gas meter normally has to be driven by a battery for 10 years, and obtains a pressure waveform to perform flow rate measurement once every about 2 seconds and judgment processing for determining whether a gas appliance has been used or the like. If the processing is executed in parallel, the power consumption will be great.

  In this specification, a part of the technology of Japanese Patent Application No. 2008-86022 is described. However, this description does not recognize the publicity of the technology of Japanese Patent Application No. 2008-86022. Moreover, publicity is not recognized about the judgment whether the gas appliance based on the gas flow rate was used.

  The present invention has been made to solve such a conventional problem, and the object of the present invention is to suppress an increase in power consumption when judging whether or not a gas appliance has been used. Is to provide a simple determination apparatus and determination method.

  The determination device of the present invention includes a normal measurement mode execution unit that measures the gas flow rate in the flow path at predetermined intervals based on an electrical signal from the flow sensor, and the current flow rate measurement by the normal measurement mode execution unit is completed. Between the first flow measurement and the next flow measurement, a simple measurement mode execution means for measuring a change in the gas flow rate exceeding a predetermined value based on an electric signal from the flow sensor, and a change in the gas flow rate by the simple measurement mode execution means. Is measured, a measurement target consisting of at least one of the gas flow rate based on the electrical signal from the flow sensor and the gas pressure in the flow path based on the electrical signal from the pressure sensor is measured, and the waveform of the measurement target is measured. And a high-speed measurement mode execution means for acquiring.

  According to this determination apparatus, the gas flow rate in the flow path is measured every predetermined time, and the change in the gas flow rate exceeding the predetermined value after the current flow rate measurement is finished and the next flow rate measurement is started. Measure. When a change in the gas flow rate is measured, a measurement target consisting of at least one of the gas flow rate and the gas pressure is measured, and a waveform of the measurement target is acquired. As described above, the acquisition of the waveform to be measured is performed only when a change in gas flow rate exceeding a predetermined value is measured between the end of the current flow rate measurement and the start of the next flow rate measurement. It will be. As a result, the acquisition of the waveform to be measured is not always performed, but is performed only in a specific time zone, and an increase in power consumption of a calculation unit such as a microcomputer is suppressed. Therefore, when determining whether or not a gas appliance has been used, an increase in power consumption of a calculation unit such as a microcomputer can be suppressed.

  Moreover, in the determination apparatus of this invention, it is preferable that a high-speed measurement mode execution means determines at least one of whether the gas appliance was used and the gas leak generate | occur | produced based on the waveform of measurement object.

  According to this determination apparatus, it is determined whether at least one of the gas appliance has been used and the gas leakage has occurred. For this reason, the gas appliance is used not only when the gas flow change exceeding a predetermined value is measured between the end of the current flow measurement and the start of the next flow measurement, and it is determined that a gas leak has occurred. Even when it is determined whether or not a gas appliance has been used, if it is determined that the gas appliance is not being used, it can be determined that a gas leak has occurred. In this way, it is possible to make a special judgment regarding gas leakage, and security processing such as shut-off valve control can be performed quickly.

  Further, in the determination device of the present invention, the high-speed measurement mode execution means is a gas leak based on the waveform to be measured, is the use of a gas appliance having a governor among the gas appliances, or It is preferable to determine whether the gas appliance is not used.

  According to this determination apparatus, based on the waveform to be measured, it is a gas leak, a gas appliance having a governor among gas appliances, or a gas appliance having no governor. Determine whether. Here, there is a characteristic difference in the frequency and amplitude of the waveform of pressure and flow rate when a gas leak occurs, when the gas appliance having the governor is started, and when the gas appliance without the governor is started. Therefore, from the frequency and amplitude of the waveform to be measured, it is possible to determine whether it is a gas leak or the use of a gas appliance having a governor, or a gas appliance without a governor. This can help prevent false detections.

  Moreover, in the determination apparatus of this invention, it is preferable that a high-speed measurement mode execution means determines the kind of gas appliance based on the waveform of measurement object.

  According to this determination device, the type of the gas appliance is determined based on the waveform to be measured. Here, when the gas appliance is used, a characteristic appears in frequency and amplitude for each type of gas appliance. For this reason, the kind of gas appliance can be judged based on the waveform of measurement object. In particular, if the type of gas appliance can be specified, the gas fee can be discounted when a specific gas appliance is used.

  Moreover, in the determination apparatus of this invention, it is preferable that a high-speed measurement mode execution means measures a measurement object only for specific time, and a simple measurement mode execution means measures the change of a gas flow rate again after progress of specific time.

  According to this determination apparatus, the high-speed measurement mode execution unit measures the measurement target for a specific time, and the simple measurement mode execution unit measures the change in the gas flow rate again after the specific time has elapsed. As described above, after determining whether or not the gas appliance is used, the change in the gas flow rate is measured again, and the determination processing such as the use of the gas appliance can be executed only for the time obtained by adding the calculation time to the specific time.

  In the determination device of the present invention, the simple measurement mode execution means measures a change in the flow rate a plurality of times from the end of the current flow measurement by the regular measurement mode execution means to the start of the next flow measurement. It is preferable.

  According to this determination device, since the change in the flow rate is measured a plurality of times between the end of the current flow rate measurement and the start of the next flow rate measurement, the change in the flow rate is determined at fine time intervals. The possibility of losing the occurrence of flow rate changes can be reduced.

  In the determination device of the present invention, the normal measurement mode execution means increases the measurement interval for a predetermined time when the difference between the flow rate detected this time and the flow rate detected in the past is within a certain value continuously several times. It is preferable to change the flow rate and measure the flow rate.

  According to this determination apparatus, when the difference between the flow rate detected this time and the flow rate detected in the past is within a certain value, the flow rate is measured by changing the measurement interval for a predetermined time longer. For this reason, when a certain amount of gas is used for a long time, for example, when using a gas stove to stew for a long time, the measurement interval is lengthened, and the power consumption is further reduced when there is no change in the flow rate. can do.

  In the determination apparatus of the present invention, it is preferable that the flow rate sensor is an ultrasonic type, and the number of times of ultrasonic measurement by the simple measurement mode executing unit is smaller than the number of times of ultrasonic measurement by the normal measurement mode executing unit.

  According to this determination apparatus, the number of times of ultrasonic measurement by the simple measurement mode execution means is smaller than the number of times of ultrasonic measurement by the normal measurement mode execution means. The increase in power consumption can be suppressed for the measurement of the flow rate change performed at the same time, and the burden on the battery due to the execution of the flow rate change measurement process can be reduced.

  In the determination apparatus of the present invention, it is preferable that the flow rate sensor is an ultrasonic type, and the number of times of ultrasonic measurement by the high-speed measurement mode execution unit is smaller than the number of times of ultrasonic measurement by the normal measurement mode execution unit.

  According to this determination apparatus, the number of times of ultrasonic measurement by the high-speed measurement mode executing means is less than the number of times of ultrasonic measurement by the normal measurement mode executing means. And the burden on the battery due to the execution of the determination process such as the use of the gas appliance can be reduced.

  In the determination apparatus of the present invention, the flow rate sensor is an ultrasonic type, and the clock frequency for the simple measurement mode execution means to measure the propagation time is the clock frequency for the normal measurement mode execution means to measure the propagation time. It is preferable to be smaller.

  According to this determination apparatus, since the clock frequency for the simple measurement mode execution means to measure the propagation time is smaller than the clock frequency for the normal measurement mode execution means to measure the propagation time, the normal measurement mode The increase in power consumption can be suppressed for the measurement of the flow rate change performed during the gas flow rate measurement interval by the execution means, and the burden on the battery due to the execution of the flow rate change measurement process can be reduced.

  In the determination apparatus of the present invention, the flow rate sensor is an ultrasonic type, and whether or not the change in the gas flow rate exceeding a predetermined value is measured by the simple measurement mode execution means is determined by whether the ultrasonic propagation time in the current measurement is measured. It is preferable to make a determination based on whether or not the time has changed by a certain value or more than the past propagation time.

  According to this determination apparatus, whether or not the change in the gas flow rate exceeding the predetermined value has been measured by the simple measurement mode execution unit is determined by a change in the ultrasonic propagation time in the current measurement by a certain value or more than the past propagation time. Judgment based on whether or not. For this reason, when the gas flow rate is detected by ultrasonic waves, the change in the gas flow rate can be known from the difference in the propagation time of the ultrasonic waves, and it is not necessary to calculate the gas flow rate itself, thereby reducing the amount of calculation. Therefore, power consumption can be further reduced.

  In the determination apparatus of the present invention, it is preferable that the flow rate sensor is a thermal type, and the heater voltage by the simple measurement mode execution means is smaller than the heater voltage by the normal measurement mode execution means.

  According to this determination apparatus, since the heater voltage by the simple measurement mode execution means is smaller than the heater voltage by the normal measurement mode execution means, the power consumption of the heater when measuring a change in gas flow rate is reduced. The burden on the battery due to the execution of the flow rate change measurement process can be reduced.

  In the determination apparatus of the present invention, it is preferable that the flow rate sensor is a thermal type, and the heater voltage by the high-speed measurement mode execution unit is smaller than the heater voltage by the normal measurement mode execution unit.

  According to this determination apparatus, since the heater voltage by the high-speed measurement mode execution unit is smaller than the heater voltage by the normal measurement mode execution unit, the power consumption of the heater in the determination process such as use of the gas appliance is reduced. In addition, it is possible to reduce the burden on the battery due to the execution of judgment processing such as the use of gas appliances.

  In addition, the determination method of the present invention is such that the normal measurement mode execution step for measuring the gas flow rate in the flow path at predetermined time intervals based on the electrical signal from the flow sensor and the current flow measurement in the normal measurement mode execution step are completed. Gas flow rate in the simple measurement mode execution step and the simple measurement mode execution step for measuring a change in the gas flow rate exceeding a predetermined value based on the electrical signal from the flow rate sensor until the next flow measurement starts. When a change in the flow rate is measured, a measurement target consisting of at least one of a gas flow rate based on the electrical signal from the flow sensor and a gas pressure in the flow path based on the electrical signal from the pressure sensor is measured. And a high-speed measurement mode execution step for acquiring the waveform of the above.

  According to this determination method, the gas flow rate in the flow path is measured every predetermined time, and the change in the gas flow rate exceeding the predetermined value after the current flow rate measurement is finished and the next flow rate measurement is started. Measure. When a change in the gas flow rate is measured, a measurement target consisting of at least one of the gas flow rate and the gas pressure is measured, and a waveform of the measurement target is acquired. As described above, the acquisition of the waveform to be measured is performed only when a change in gas flow rate exceeding a predetermined value is measured between the end of the current flow rate measurement and the start of the next flow rate measurement. It will be. As a result, the acquisition of the waveform to be measured is not always performed, but is performed only in a specific time zone, and an increase in power consumption of a calculation unit such as a microcomputer is suppressed. Therefore, when determining whether or not a gas appliance has been used, an increase in power consumption of a calculation unit such as a microcomputer can be suppressed.

  According to the present invention, it is possible to provide a determination device and a determination method capable of suppressing an increase in power consumption of a calculation unit such as a microcomputer when determining whether a gas appliance has been used.

It is a lineblock diagram of a gas supply system containing a measuring device concerning an embodiment of the present invention. FIG. 2 is a side sectional view showing an example of the governor shown in FIG. 1. It is a lineblock diagram of the gas meter concerning the embodiment of the present invention. It is a state transition diagram which shows the outline of the mode transfer method of the gas meter which concerns on this embodiment. It is a graph which shows the mode of a pressure change when the use of the gas appliance with a governor is started. It is a graph which shows the mode of a pressure change when the use of a gas appliance without a governor is started. It is the schematic which shows the mode of supply of the fuel gas in a gas appliance without a governor. It is a graph which shows the mode of the pressure change at the time of gas leak. It is a flowchart which shows the judgment method of the gas meter which concerns on this embodiment, and has shown the operation | movement in regular measurement mode. It is a flowchart which shows the judgment method of the gas meter which concerns on this embodiment, and has shown operation | movement in simple measurement mode. It is a flowchart which shows the judgment method of the gas meter which concerns on this embodiment, and has shown the operation | movement in high-speed measurement mode. It is a flowchart which shows the detail of step S33 shown in FIG. 11, and has shown the process regarding use of a gas appliance, and gas leak judgment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a gas supply system including a measuring device according to an embodiment of the present invention. The gas supply system 1 supplies fuel gas to each gas appliance 10, and includes a plurality of gas appliances 10, a gas supply source regulator 20, pipes 31 and 32, a gas meter (determination device) 40, and the like. It has. In the example illustrated in FIG. 1, the gas meter 40 is described as an example of the determination device, but the determination device is not limited to the gas meter 40 and may be another device.

  The adjuster 20 adjusts the fuel gas from the upstream to a predetermined pressure and flows it through the first pipe 31. The first pipe 31 connects the regulator 20 and the gas meter 40. The second pipe 32 is a pipe that connects the gas meter 40 and the gas appliance 10. The gas meter 40 measures the flow rate of the fuel gas and displays the integrated flow rate. In such a gas supply system 1, a flow path connected to the first pipe 31 and the second pipe 32 is formed in the gas meter 40, and the fuel gas flowing through the regulator 20 flows from the first pipe 31 to the gas meter 40, And the gas appliance 10 is reached through the second pipe 32 and burned in the gas appliance 10.

  The gas appliance 10 generally includes a shut-off valve 12, a governor 13, and a burner 14. The shut-off valve 12 is a valve provided in the gas appliance 10. The governor 13 has a governor inner valve 13a, and adjusts the pressure of the gas supplied to the burner 14 of the gas appliance 10 by the opening degree of the governor inner valve 13a. The pressure-adjusted fuel gas reaches the burner 14 through the nozzle 13b at the tip of the governor 13 and burns. Note that not all the gas appliances 10 have the governor 13, and some gas appliances 10 do not have the governor 13 such as a gas stove.

  FIG. 2 is a side sectional view showing an example of the governor 13 shown in FIG. In addition, in FIG. 2, only an example of the governor 13 is shown, and the configuration of the governor 13 is not limited to that shown in FIG. Further, the governor 13 shown in FIG. 2 is illustrated with the nozzle 13b shown in FIG. 1 omitted.

  As shown in FIG. 2, the governor 13 uses a part of the internal space formed by the outer wall 13c and the governor cap 13d as a gas flow path. Such a governor 13 includes a diaphragm 13e, an adjustment spring 13f, and an adjustment screw 13g in the internal space in addition to the governor inner valve 13a.

  The diaphragm 13 e is a film-like member that partitions the internal space of the governor 13. A governor inner valve 13a is attached to the diaphragm 13e on one side (flow channel side). Further, an adjustment spring 13f is attached to the other side (side not functioning as a flow path) of the diaphragm 13e. The adjustment spring 13f has a diaphragm 13e attached to one end and an adjustment screw 13g attached to the other end. The adjustment screw 13g is structured to be fixed to the inner wall of the governor 13 in which the thread groove is formed, and the compression rate of the adjustment spring 13f can be changed by changing the fixing position with the thread groove. Further, the adjusting screw 13g is not exposed to the outside, and has a structure covered with a governor cap 13d.

  The outer wall 13c of the governor 13 is formed with an air hole 13h that communicates with the other side of the diaphragm 13e. For this reason, the other side of the diaphragm 13e is air pressure. Further, in the example shown in FIG. 2, the governor inner valve 13a has a hemispherical shape, and the opening ratio of the passage port 13i can be controlled by vertical movement.

  In such a governor 13, when the gas pressure on the gas inlet side increases, the diaphragm 13e is pushed up, and at the same time, the governor inner valve 13a attached to the diaphragm 13e is also raised. Thereby, the opening ratio of the passage port 13i becomes small, and the gas flow rate decreases. On the other hand, when the gas pressure on the gas inlet side is lowered, the diaphragm 13e is lowered, and at the same time, the governor inner valve 13a attached to the diaphragm 13e is also lowered. Thereby, the opening ratio of the passage port 13i increases, and the gas flow rate increases. In this manner, the governor 13 adjusts the downstream pressure by keeping the downstream flow rate constant with respect to the upstream pressure fluctuation.

  FIG. 3 is a configuration diagram of the gas meter 40 according to the embodiment of the present invention. The gas meter 40 shown in the figure includes a flow rate sensor 41, a pressure sensor 42, a microcomputer 43, and a drive circuit 44.

  The flow sensor 41 is installed in the flow path in the gas meter 40 and detects the gas flow rate in the flow path. In the case where the gas meter 40 according to the present embodiment is an ultrasonic gas meter, the flow sensor 41 is configured by two acoustic transducers or the like composed of, for example, piezoelectric vibrators arranged at a predetermined distance in the flow path. . When the gas meter 40 according to the present embodiment is a gas meter equipped with a thermal sensor such as a flow sensor, the gas meter 40 includes a heater that generates a temperature distribution, a temperature sensor that generates a signal corresponding to the temperature distribution, and the like.

  The pressure sensor 42 is for detecting the gas pressure of the gas present in the flow path in the gas meter 40. The pressure sensor 42 is not limited to the flow path in the gas meter 40, and may be installed in the first pipe 31 or the second pipe 32 existing outside the gas meter 40 if possible. Similarly, the installation location of the flow sensor 41 can be changed.

  In the present embodiment, signals from the flow sensor 41 and the pressure sensor 42 are directly input to the microcomputer 43 in FIG. 3, but other elements such as an amplifier may be added between the two depending on circumstances. .

  The microcomputer 43 controls the entire gas meter 40, and performs flow rate integration control, display control, cutoff valve cutoff control, and the like. In the present embodiment, the microcomputer 43 can execute three measurement modes including a normal measurement mode, a simple measurement mode, and a high-speed measurement mode, and a normal measurement mode execution unit ( It has a normal measurement mode execution means) 43a, a simple measurement mode execution section (simple measurement mode execution means) 43b, and a high-speed measurement mode execution section (high-speed measurement mode execution means) 43c.

  The normal measurement mode execution unit 43a executes the normal measurement mode. Specifically, the normal measurement mode execution unit 43a measures the gas flow rate in the flow path every first predetermined time (predetermined time) based on the electric signal from the flow rate sensor 41. The process is executed. The simple measurement mode execution unit 43b executes the simple measurement mode. From the flow rate sensor 41 between the end of the current flow rate measurement by the regular measurement mode execution unit 43a and the start of the next flow rate measurement. Of measuring a change in gas flow rate exceeding a predetermined value (for example, 1.5 L / hr, the lowest flow rate that can be measured by the gas meter 40, or a flow rate that cannot be generated by pulsation of the flow rate) Is to execute. The high-speed measurement mode execution unit 43c executes the high-speed measurement mode. When the flow rate change is measured by the simple measurement mode execution unit 43b, the gas pressure in the flow path based on the electric signal from the pressure sensor 42 is measured. To determine whether the gas appliance 10 has been used and whether a gas leak has occurred.

  The drive circuit 44 controls driving of the flow sensor 41 and the pressure sensor 42, and includes a normal measurement mode drive circuit 44a, a simple measurement mode drive circuit 44b, and a high-speed measurement mode drive circuit 44c. These drive circuits 44a to 44c correspond to the three measurement modes described above. Therefore, the normal measurement mode drive circuit 44a functions when the gas meter 40 is to be driven in the normal measurement mode, and the simple measurement mode drive circuit 44b functions when it is desired to drive the gas meter 40 in the simple measurement mode. Similarly, when it is desired to drive in the high-speed measurement mode, the high-speed measurement mode drive circuit 44c functions.

  Here, each measurement mode will be described in detail. First, the normal measurement mode is a mode in which the gas flow rate is measured at a measurement interval once every first predetermined time. More specifically, the normal measurement mode is a mode in which the gas flow rate is measured at a measurement interval of about once every 2 seconds in order to obtain the integrated flow rate. In the gas meter 40 according to the present embodiment, the gas flow rate is constantly measured at an interval of about once every 2 seconds, and the value of the integrated flow rate displayed on the meter body is increased according to the measured gas flow rate. Become.

  The simple measurement mode is a mode for measuring a change in the gas flow rate over a predetermined value at a timing once every second predetermined time based on an electric signal from the flow sensor 41. More specifically, in the simple measurement mode, a change in gas flow rate is measured at a measurement interval of about once every 0.1 seconds so as to compensate for a measurement interval of about once every 2 seconds in the normal measurement mode. is there. Such a simple measurement mode does not require extremely high measurement accuracy of the flow rate, and it is only necessary to determine a change in the flow rate. Therefore, power consumption is smaller than that in the normal measurement mode. This point will be explained in detail.

  For example, when the flow sensor 41 according to the present embodiment is an ultrasonic sensor, the simple measurement mode execution unit 43b makes the ultrasonic measurement count smaller than the ultrasonic measurement count in the normal measurement mode. Thereby, the electric power required for ultrasonic oscillation and the electric power by calculation can be suppressed, and power consumption can be suppressed. If the number of ultrasonic measurements is reduced, the measurement accuracy of the gas flow rate deteriorates. However, in the simple measurement mode, only a change in the flow rate needs to be measured, so there is no problem with a slight decrease in accuracy.

  For example, when the number of ultrasonic measurements in the normal measurement mode is 100, if the number of ultrasonic measurements in the simple measurement mode is 10, the measurement accuracy is about 1/3 (≈√ (1/10)). However, the power consumption is reduced to 1/10. If the minimum sensitivity in the normal measurement mode is 0.5 L / hr, the sensitivity in the simple measurement mode is about 1.5 L / hr. Even if a small flow rate of 1.5 L / hr continues for 2 seconds due to gas leakage, there is only gas leakage of about 0.8 cc, and it is sufficient to measure the flow rate change of less than 1.5 L / hr in the normal measurement mode. In the simple measurement mode, it is sufficient to measure a flow rate change of 1.5 L / hr or more.

  Further, the power consumption in the simple measurement mode may be reduced by a method different from the above. For example, when the flow sensor 41 according to this embodiment is an ultrasonic sensor, the simple measurement mode execution unit 43b uses a clock frequency for measuring the propagation time as a clock frequency for measuring the propagation time in the normal measurement mode. Smaller than. This is because power consumption required for the clock in the simple measurement mode can be suppressed. If the clock frequency is reduced, the measurement accuracy is deteriorated. However, for the same reason as described above, there is no problem with a slight decrease in accuracy in the simple measurement mode.

  Furthermore, when the flow sensor 41 according to the present embodiment is a thermal sensor such as a flow sensor, the simple measurement mode execution unit 43b makes the heater voltage smaller than the heater voltage in the normal measurement mode. This is because the supply voltage to the heater is reduced in the simple measurement mode, and power consumption can be suppressed. When the heater voltage is reduced, the measurement accuracy is deteriorated. However, for the same reason as described above, there is no problem with a slight decrease in accuracy in the simple measurement mode.

  In addition, the high-speed measurement mode is a mode for detecting the gas pressure in the flow path, and is measured once every third predetermined time when a change in gas flow rate of a predetermined value or more is measured in the simple measurement mode. In this mode, the gas pressure is measured at the timing. More specifically, the high-speed measurement mode is a mode in which the gas pressure is measured at a measurement interval of about once every 1 millisecond. In this high-speed measurement mode, the high-speed measurement mode execution unit 43c captures a change in gas pressure, determines use of the gas appliance 10 installed on the downstream side of the gas flow path, and determines whether a gas leak has occurred. To do. Note that there is a correlation between a change in gas pressure and a change in gas flow rate. Therefore, in the high-speed measurement mode, the gas flow rate may be measured at a measurement interval of about once every 1 millisecond, or both the gas pressure and the gas flow rate are measured at a measurement interval of about once every 1 millisecond. May be. In addition, the measurement interval in the high-speed measurement mode is not limited to 1 millisecond, but may be as short as 0.1 millisecond, or may be as long as 10 milliseconds or 100 milliseconds.

  In the gas supply system 1 as described above, the mode of the gas meter 40 is changed as follows. FIG. 4 is a state transition diagram illustrating an outline of the mode transition method of the gas meter 40 according to the present embodiment. As shown in FIG. 4, first, the gas meter 40 is driven in the normal measurement mode. That is, the normal measurement mode execution unit 43a and the normal measurement mode drive circuit 44a function, and the flow rate measurement is executed about once every 2 seconds. Here, the flow rate measurement in the normal measurement mode does not require the entire time of about 2 seconds, and is performed using a part of time such as 200 milliseconds, for example.

  For example, it is assumed that the measurement ends after a time of 200 milliseconds elapses (S1). Thereby, the normal measurement mode execution unit 43a ends the execution of the normal measurement mode, and the simple measurement mode execution unit 43b executes the simple measurement mode. The simple measurement mode drive circuit 44b functions together with the simple measurement mode execution unit 43b, and a flow rate change of a predetermined value or more is measured at a timing of about once every 0.1 second. Therefore, the simple measurement mode execution unit 43b measures the change in the flow rate a plurality of times from the end of the current measurement by the regular measurement mode execution unit 43a to the start of the next measurement.

  Next, it is assumed that about 2 seconds have elapsed since the start of measurement in the previous regular measurement mode in the state in which the simple measurement mode is being executed (S2). Thereby, the simple measurement mode execution unit 43b ends the execution of the simple measurement mode, and the normal measurement mode execution unit 43a executes the normal measurement mode.

  Further, it is assumed that a flow rate change of a predetermined value or more is measured during the execution of the simple measurement mode (S3). Thereby, the simple measurement mode execution unit 43b ends the execution of the simple measurement mode, and the high-speed measurement mode execution unit 43c executes the high-speed measurement mode. The high-speed measurement mode driving circuit 44c functions together with the high-speed measurement mode execution unit 43c, and the gas pressure is measured at a timing of about once every 1 millisecond. Whether the high-speed measurement mode execution unit 43c corresponds to one of the use state of the gas appliance 10 with the governor, the use of the gas appliance 10 without the governor, or the gas leakage based on the gas pressure measured in the high-speed measurement mode. Judge whether or not. When it is determined that gas leakage has occurred in the high-speed measurement mode, the gas meter 40 operates the shut-off valve to close the flow path and prevent gas leakage.

  Further, it is assumed that measurement of gas pressure in the high-speed measurement mode is executed for a specific time (for example, about 2 seconds) (S4). As a result, the high-speed measurement mode execution unit 43c ends the execution of the high-speed measurement mode, and the simple measurement mode execution unit 43b executes the simple measurement mode. The simple measurement mode drive circuit 44b functions together with the simple measurement mode execution unit 43b, and a flow rate change of a predetermined value or more is measured at a timing of about once every 0.1 second. If the flow measurement start timing in the regular measurement mode is reached at the time of transition to the simple measurement mode, the measurement mode transitions to the regular measurement mode immediately after transition to the simple measurement mode.

  Further, in the high-speed measurement mode, in a special case, the high-speed measurement mode is continued even after a specific time has elapsed (S5). Here, the special case is, for example, a case where the gas appliance 10 has failed to ignite once and is expected to start the ignition operation again immediately after the failure.

  In the description with reference to FIG. 4, each of the normal measurement mode, the simple measurement mode, and the high-speed measurement mode is not executed redundantly. It may be overlapped. For example, even during the transition to the high-speed measurement mode, when the time of about 2 seconds, which is the measurement interval in the normal measurement mode, has passed, the flow measurement in the normal measurement mode is performed. Also good. This is because the situation where the measurement of the flow rate is interrupted can be prevented.

  Next, the use of the gas appliance 10 in the high-speed measurement mode and a determination method for gas leakage will be described. When the gas appliance 10 with the governor is used, when the gas appliance 10 without the governor is used, and when a gas leak occurs, different pressure changes are shown. Specifically, the amplitude and frequency of the pressure change waveform are characteristic. In the high-speed measurement mode, the microcomputer 43 determines whether or not the governor-equipped gas appliance 10 is used, whether or not the governor-less gas appliance 10 is used, and whether a gas leak has occurred, from the amplitude and frequency of the pressure change. Determine whether.

  FIG. 5 is a graph showing how the pressure changes when the use of the gas appliance 10 with the governor is started. In FIG. 5, the vertical axis represents the pressure change amount (kPa), and the horizontal axis represents the elapsed time (seconds) after the use of the governor-equipped gas appliance 10 is started.

  When the use of the gas appliance 10 with the governor is started, the pressure becomes a stable state after exhibiting the predetermined amplitude shown in FIG. Specifically, immediately after the start of use of the gas appliance 10 with the governor, after showing a pressure drop to just “−0.1” kPa (see symbol a1), the pressure rises to about “0.05” kPa. (See symbol a2). After that, the pressure shows a pressure drop to about “−0.05” kPa (see symbol a3), and then shows a pressure rise to about “0.05” kPa (see symbol a4). Thereafter, the pressure repeatedly oscillates while the amplitude gradually decreases, and finally becomes a stable state in which there is no pressure change.

  The reason why such pressure vibration occurs is that an adjustment spring 13 f is provided in the governor 13. That is, when the use of the gas appliance 10 with the governor is started, the adjustment spring 13f vibrates, the governor inner valve 13a also vibrates, and the opening ratio of the passage port 13i changes gradually and gradually. Because it does.

  In particular, at the start of use of the gas appliance 10 with a governor, characteristics are seen in the frequency and amplitude of pressure vibration. Specifically, since the adjustment spring 13f vibrates in small increments, the pressure shows fine vibration. As a result, the pressure waveform contains many relatively high frequency components. Moreover, since the passage opening 13i becomes larger or smaller due to the vibration of the adjustment spring 13f at the start of use of the gas appliance 10 with the governor, the pressure waveform shows a large amplitude.

なる演算式で表すことができる。ここで、Ｃは振幅を示し、ｋは摩擦力（減衰定数）を示し、ωは復元力を示し、αは初期位相を示している。この式は多くの周波数ｆ_ｉ＝ω_ｉ／２πの振動の重ね合わせであることを示している。 The pressure P is

It can be expressed by the following equation. Here, C represents the amplitude, k represents the frictional force (attenuation constant), ω represents the restoring force, and α represents the initial phase. This equation indicates that this is a superposition of vibrations of many frequencies f _i = ω _i / 2π.

  FIG. 6 is a graph showing the pressure change when the use of the governorless gas appliance 10 is started. In FIG. 6, the vertical axis represents the pressure change amount (kPa), and the horizontal axis represents the elapsed time (seconds) after the use of the governorless gas appliance 10 is started.

  When the use of the governorless gas appliance 10 is started, the pressure is in a stable state after showing the predetermined amplitude shown in FIG. Specifically, immediately after the start of use of the gas appliance 10 with the governor, after showing a pressure drop to “−0.1” kPa (see b1), the pressure rises to about “0.01” kPa. (See symbol b2). Thereafter, the pressure shows a pressure drop to about “−0.05” kPa (see symbol b3). Thereafter, the pressure repeatedly vibrates with no pressure increase. Then, the amplitude gradually decreases, and finally a stable state in which there is no pressure change is obtained. The reason why such pressure vibration occurs is as follows.

  FIG. 7 is a schematic view showing a state of supply of fuel gas in the governorless gas appliance 10. As shown in FIG. 7, when the governorless gas appliance 10 is used, the fuel gas reaches the burner 14 and the like from the second pipe 32 through the nozzle holder 100. Here, when a gas having a flow velocity flows into the nozzle holder 100, the flow rate does not decrease suddenly due to the inertial force, but the gas is compressed and the pressure rises. Thereafter, the inflow flow velocity becomes small (in some cases, a reverse flow) due to the increased pressure, and the pressure decreases. By repeating this, vibration of compression and expansion occurs.

  As described above, the pressure oscillates when the gas appliance with governor 10 is used and when the gas appliance 10 without governor is used. However, when the pressure waveform shown in FIG. 6 is compared with the pressure waveform shown in FIG. 5, there are the following differences.

  First, the governor-equipped gas appliance 10 has a substance that vibrates finely like the adjustment spring 13f, whereas the governor-less gas appliance 10 does not have such a substance. Therefore, although the pressure waveform shown in FIG. 6 shows vibration in the same manner as the pressure waveform shown in FIG. 5, the vibration frequency as a whole is lower than the pressure waveform shown in FIG.

  Further, in the case of the gas appliance 10 with the governor, the amplitude is increased by the vibration of the adjustment spring 13f. However, in the case of the gas appliance 10 with the governor, there is no adjustment spring 13f, and vibration due to the compressibility of the nozzle holder 100 occurs. There is only. For this reason, the pressure waveform shown in FIG. 6 has a smaller amplitude than the pressure waveform shown in FIG.

  From such characteristics, the microcomputer 43 can determine whether the gas appliance with governor 10 is used or whether the gas appliance 10 without governor is used.

  FIG. 8 is a graph showing a state of pressure change at the time of gas leakage. In FIG. 8, the vertical axis represents the pressure change amount (kPa), and the horizontal axis represents the elapsed time (seconds) after the gas leak occurred.

  As shown in FIG. 8, when a gas leak occurs, the pressure gradually decreases without showing a clear vibration. Thus, in the case of gas leakage, neither the vibration of the adjustment spring 13f nor the vibration due to the compressibility of the nozzle holder 100 occurs, so no clear vibration is seen in the pressure waveform.

  As described above, there is a characteristic difference in the frequency and amplitude of the pressure waveform between the start of use of the gas appliance 10 with governor, the start of use of the gas appliance 10 without governor, and the occurrence of gas leakage. From the above characteristics, the microcomputer 43 can determine whether the gas appliance with governor 10 is used, the gas appliance 10 without governor is used, or a gas leak. In determining whether or not the gas appliance 10 with the governor is used, the microcomputer 43 may use a value of frequency or amplitude, or a calculation result indicating the frequency or amplitude (for example, spectral data obtained by Fourier transform). ) May be used.

  Further, the characteristics of the frequency and amplitude of the gas pressure described with reference to FIGS. 5 to 8 are generated about several seconds after the pressure fluctuation starts. Therefore, in the high-speed measurement mode, it is sufficient to measure the pressure for a specific time (about 0.3 to 2 seconds). In the gas meter 40 according to the present embodiment, whether or not the gas appliance 10 with the governor has been used in a short time. In addition, it is possible to determine whether or not the governorless gas appliance 10 has been used and whether or not a gas leak has occurred.

  Next, the operation of the gas meter 40 according to the present embodiment will be described with reference to a flowchart. In the following flowchart, an ultrasonic gas meter will be described as an example. FIG. 9 is a flowchart showing a determination method of the gas meter 40 according to the present embodiment, and shows an operation in the normal measurement mode.

  In the normal measurement mode, the normal measurement mode execution unit 43a first sets a clock frequency for measuring the propagation time to a high speed (S10). Specifically, the gas meter 40 uses a clock frequency of several tens of MHz in the simple measurement mode, while using a clock frequency of several hundreds of MHz, which is about 10 times in the normal measurement mode.

  After setting the clock frequency, the normal measurement mode execution unit 43a measures the flow rate based on the electrical signal from the flow rate sensor 41 (S11). And the regular measurement mode execution part 43a integrates the flow volume measured in step S11 (S12). Next, the normal measurement mode execution unit 43a determines whether or not the case where the difference between the flow rate measured in step S11 and the flow rate measured in the past is within a certain value is continued a plurality of times (S13). Here, the flow rate measured in the past may be a flow rate measured last time, or may be an average value of the flow rates of a plurality of past times.

  When it is determined that the difference between the flow rate measured in step S11 and the flow rate measured in the past is within a certain value is not consecutive multiple times (S13: NO), the process proceeds to step S15. On the other hand, when it is determined that the case where the difference between the flow rate measured in step S11 and the flow rate measured in the past is within a certain value is continued a plurality of times (S13: YES), the normal measurement mode execution unit 43a 1 The predetermined time is extended (S14). That is, the measurement interval of the flow rate of about 2 seconds is changed long, for example, 4 seconds or 10 seconds. Thereby, power consumption can be further reduced when there is no flow rate change, for example, when using a gas stove for a long time of cooking.

  Thereafter, the normal measurement mode execution unit 43a generates a first trigger signal (S15). Thereby, the simple measurement mode execution part 43b and the simple measurement mode drive circuit 44b function, and the measurement mode shifts to the simple measurement mode (S16). Thereafter, the process shown in FIG. 9 ends.

  FIG. 10 is a flowchart showing a determination method of the gas meter 40 according to the present embodiment, and shows an operation in the simple measurement mode. In the simple measurement mode, the simple measurement mode execution unit 43b first sets the clock frequency for measuring the propagation time to a low speed (S20). Specifically, the gas meter 40 uses a clock frequency of several tens of MHz, which is about 1/10 of the clock frequency in the normal measurement mode. Thereby, the power consumption in the simple measurement mode is reduced.

  After the clock setting, the simple measurement mode execution unit 43b determines whether or not a first predetermined time (for example, 2 seconds) has elapsed (S21). That is, it is determined whether or not the measurement timing in the normal measurement mode has arrived. When it is determined that the first predetermined time has elapsed (S21: YES), the simple measurement mode execution unit 43b generates a second trigger signal (S22). As a result, the normal measurement mode execution unit 43a and the normal measurement mode drive circuit 44a function, and the measurement mode shifts to the normal measurement mode (S23). Thereafter, the process shown in FIG. 10 ends.

  If it is determined that the first predetermined time has not elapsed (S21: NO), the simple measurement mode execution unit 43b determines whether a second predetermined time (for example, 0.1 second) has elapsed (S24). . That is, it is determined whether or not the measurement timing in the simple measurement mode has arrived. When it is determined that the second predetermined time has not elapsed (S24: NO), this process is repeated until it is determined that the second predetermined time has elapsed.

  On the other hand, when it is determined that the second predetermined time has elapsed (S24: YES), the simple measurement mode execution unit 43b acquires information on the propagation time and stores it as a past propagation time for the next determination (S25). Then, the simple measurement mode execution unit 43b determines whether or not the ultrasonic propagation time in the current measurement has changed by a certain value (for example, a value corresponding to 1.5 L / hr) or more than the past propagation time ( S26). Here, the past propagation time may be the propagation time at the previous measurement, or may be the average value of the propagation times for the past multiple times.

  If it is determined that the ultrasonic propagation time in this measurement has not changed by a certain value or more than the past propagation time, or if no past propagation time is stored (S26: NO), the process proceeds to step S21. Transition. The case where the past propagation time is not stored is, for example, immediately after the transition to the simple measurement mode. On the other hand, when it is determined that the ultrasonic propagation time in the current measurement has changed by a certain value or more than the past propagation time (S26: YES), the simple measurement mode execution unit 43b generates a third trigger signal (S27). . As a result, the high-speed measurement mode execution unit 43c and the high-speed measurement mode drive circuit 44c function, and the measurement mode shifts to the high-speed measurement mode (S28).

  Thereafter, when the first predetermined time is extended from the initial value, the first predetermined time is returned to the initial value, and the past propagation time is erased (S29). Specifically, when the initial value is 2 seconds, when the current value is 10 seconds, the storage of the past propagation time is erased after returning to the initial value of 2 seconds. . Thereafter, the process shown in FIG. 10 ends.

  FIG. 11 is a flowchart showing a determination method of the gas meter 40 according to this embodiment, and shows an operation in the high-speed measurement mode. As shown in FIG. 11, first, the high-speed measurement mode execution unit 43c determines whether or not a third predetermined time (for example, 1 millisecond) has elapsed (S30). That is, it is determined whether or not the measurement timing in the high-speed measurement mode has arrived.

  When it is determined that the third predetermined time has not elapsed (S30: NO), this process is repeated until it is determined that the third predetermined time has elapsed. On the other hand, when it is determined that the third predetermined time has elapsed (S30: YES), the high-speed measurement mode execution unit 43c detects and detects the gas pressure in the flow path based on the signal from the pressure sensor 42. The gas pressure is stored (S31).

  Thereafter, the high-speed measurement mode execution unit 43c determines whether or not a specific time (for example, about 2 seconds) has elapsed (S32). In this process, the high-speed measurement mode execution unit 43c determines whether or not a specific time has elapsed depending on whether or not a predetermined number (eg, 2000) of pressure data has accumulated. If it is determined that the specific time has not elapsed (S32: NO), the process proceeds to step S30.

  On the other hand, when it is determined that the specific time has elapsed (S32: YES), the high-speed measurement mode execution unit 43c uses the gas appliance 10 or gas based on the gas pressure data measured and stored in step S31 during the specific time. A leak is determined (S33). Thereafter, the high-speed measurement mode execution unit 43c determines whether or not there is no gas leakage in the process of step S33 (S34).

  When it is determined that there is no gas leakage (S34: YES), the high-speed measurement mode execution unit 43c generates a fourth trigger signal (S35). As a result, the simple measurement mode execution unit 43b and the simple measurement mode drive circuit 44b function, and the measurement mode shifts to the simple measurement mode (S36). Thereafter, the process shown in FIG. 11 ends.

  On the other hand, when it is not determined that there is no gas leak (S26: NO), that is, when it is determined that there is a gas leak, the high-speed measurement mode execution unit 43c shuts off the gas supply by the shut-off valve and alerts Etc. are performed (S37). Thereafter, the process shown in FIG. 11 ends.

  In the flowchart shown in FIG. 11, the processes in steps S35 and S36 are executed when “YES” is determined in step S34, but not limited thereto, immediately after “YES” is determined in step S32. It may be executed. This is because it is possible to quickly shift to the simple measurement mode. At this time, it is desirable that the process of step S36 is a process of instructing execution of the simple measurement mode as execution by another program by multitasking.

  Further, a short time (for example, 1 to 10 seconds) may be waited between the determination of “YES” in step S34 and the execution of steps S35 and S36. This is because the vibration of the gas pressure (or flow rate) immediately after the gas appliance is used may still remain, and it may be better to perform simple measurement after the vibration has been sufficiently eliminated.

  FIG. 12 is a flowchart showing details of step S33 shown in FIG. 11, and shows processing related to use of the gas appliance 10 and determination of gas leakage. As shown in FIG. 12, first, the high-speed measurement mode execution unit 43c analyzes the frequency of the waveform of the gas pressure stored in step S31 of FIG. 11 (S40) and analyzes the amplitude (S41).

  Thereafter, the high-speed measurement mode execution unit 43c determines whether or not a frequency component equal to or higher than the discriminant value is included in the waveform based on the analysis result of step S40 (S42). If it is determined that a frequency component equal to or higher than the discriminant value is included (S42: YES), that is, if a high frequency component is included in the waveform to some extent as in the pressure waveform shown in FIG. The part 43c judges that it is use of the gas appliance 10 with a governor (S43). Then, the process illustrated in FIG. 12 ends, and the process proceeds to step S34 in FIG.

  Further, when it is determined that the frequency component equal to or higher than the discriminant value is not included in the waveform (S42: NO), the high-speed measurement mode execution unit 43c determines the amplitude value of the first peak (that is, the pressure changes). The maximum value when the amplitude first increases in the positive direction from the beginning, or the value when the amplitude increases most in the positive direction throughout the whole) is the original pressure (pressure of “0” on the vertical axis in FIG. 5) It is determined whether or not the value is equal to or greater than a value obtained by adding a predetermined amount to (S44). When it is determined that the amplitude value of the first peak is equal to or greater than a value obtained by adding a predetermined amount to the original pressure (S44: YES), the high-speed measurement mode execution unit 43c determines that the gas appliance with governor 10 is used. (S43). Then, the process illustrated in FIG. 12 ends, and the process proceeds to step S34 in FIG.

  On the other hand, when it is determined that the amplitude value of the first mountain is not equal to or greater than the value obtained by adding a predetermined amount to the original pressure (S44: NO), the high-speed measurement mode execution unit 43c determines that the amplitude value of the first mountain is the original pressure. It is determined whether or not the values are substantially equivalent (specifically, the original pressure ± the specified value) (S45). When it is determined that the amplitude value of the first peak is substantially equal to the original pressure (S45: YES), the high-speed measurement mode execution unit 43c determines that the governorless gas appliance 10 is used (S46). . Then, the process illustrated in FIG. 12 ends, and the process proceeds to step S34 in FIG.

  If it is determined that the amplitude value of the first mountain is not substantially equal to the original pressure (S45: NO), the high-speed measurement mode execution unit 43c sets the amplitude value of the first mountain to the original pressure by a predetermined amount. It is determined whether the value is equal to or less than the subtracted value (S47). When it is determined that the amplitude value of the first peak is equal to or less than the value obtained by subtracting the predetermined amount from the original pressure (S47: YES), the high-speed measurement mode execution unit 43c is greater than the specified amount based on the signal from the flow sensor 41. It is determined whether or not the flow rate is detected (S48).

  When it is determined that a flow rate exceeding the specified amount is detected (S48: YES), that is, the characteristics of frequency and amplitude due to the use of the gas appliance 10 are not obtained, the gas pressure in the flow path is reduced, and the specified amount is obtained. When the above flow rate is detected, the high-speed measurement mode execution unit 43c determines that there is a gas leak (S49). Then, the process illustrated in FIG. 12 ends, and the process proceeds to step S34 in FIG.

  By the way, when it is determined that the amplitude value of the first peak is not less than or equal to the value obtained by subtracting the predetermined amount from the original pressure (S47: NO), and when it is determined that the flow rate exceeding the specified amount is not detected (S48: NO). The high-speed measurement mode execution unit 43c determines that neither the use of the gas appliance 10 nor the gas leakage is applicable (S50). Then, the process illustrated in FIG. 12 ends, and the process proceeds to step S34 in FIG.

  Note that the use of the gas appliance 10 and gas leakage are not limited to those shown in FIG. 12, and may be determined by other methods, for example. For example, if the microcomputer 43 determines “YES” in step S42 or step S44, the microcomputer 43 determines that the gas appliance 10 with the governor is used, but not limited to this, “YES” in both step S42 and step S44. If it is determined, it may be determined that the gas appliance with governor 10 is used.

  Further, the microcomputer 43 may determine that the gas appliance 10 with the governor is used when the attenuation coefficient of the pressure waveform is equal to or less than a predetermined value. In addition, the microcomputer 43 determines that the amplitude value of the first peak is the amplitude value of the first valley (that is, the minimum value when the amplitude first increases in the negative direction after the pressure changes, or most throughout the whole). When the amplitude is smaller than the value when the amplitude is increased in the negative direction, it may be determined that the gas appliance 10 with the governor is used. Furthermore, you may judge use of the gas appliance 10 with a governor combining various above-mentioned content.

  Further, the obtained waveform is subjected to Fourier transform to calculate spectrum data indicating the correlation between frequency and amplitude, and the similarity between the calculated spectrum data and the spectrum data stored in advance when the gas appliance with governor 10 is used is calculated. It may be determined that the gas appliance with governor 10 is used when the degree of similarity is equal to or higher than a specific value. In addition, the use of the governorless gas appliance 10 and the gas leakage may be similarly determined.

  Thus, according to the gas meter 40 and the determination method according to the present embodiment, the gas flow rate in the flow path is measured every predetermined time, and the next flow rate measurement is started after the current flow rate measurement is completed. Until then, the change of the gas flow rate exceeding a predetermined value is measured. When a change in the gas flow rate is measured, at least one of the gas flow rate and the gas pressure is measured to determine whether the gas appliance 10 has been used and whether a gas leak has occurred. As described above, regarding the determination of whether the gas appliance 10 has been used and whether a gas leak has occurred, the gas flow rate exceeding a predetermined value between the end of the current flow rate measurement and the start of the next flow rate measurement is determined. It will be done only when changes are measured. As a result, the determination as to whether the gas appliance 10 has been used and whether a gas leak has occurred is not always performed, but is performed only in a specific time period. An increase in power consumption will be suppressed. Therefore, in determining whether or not the gas appliance 10 has been used, an increase in power consumption of the calculation unit such as the microcomputer 43 can be suppressed.

  Further, based on a value obtained by obtaining at least one of the frequency and amplitude of the waveform from at least one waveform of the measured gas pressure and gas flow, or based on a calculation result indicating a state of at least one of the frequency and amplitude of the waveform. Determine gas leaks. Here, at the time of occurrence of gas leakage, at the start of use of the gas appliance 10 having the governor 13, and at the start of use of the gas appliance 10 without the governor 13, it is characteristic of the frequency and amplitude of the waveform of pressure and flow rate. There is a difference. Therefore, it is determined whether the gas leakage or the use of the gas appliance 10 having the governor 13 among the gas appliances 10 or the use of the gas appliance 10 having no governor is used due to this characteristic difference. This can prevent misdetection of judgment.

  The high-speed measurement mode execution unit 43c measures at least one of the gas pressure and the gas flow rate for a specific time, and the simple measurement mode execution unit 43b measures the change in the gas flow rate again after the specific time has elapsed. As described above, the change in the gas flow rate is measured again after the determination of the use of the gas appliance 10 and the like, and the determination process such as the use of the gas appliance 10 is executed only for a time obtained by adding the calculation time to the specific time. it can.

  In addition, since the change in the flow rate is measured multiple times between the end of the current flow rate measurement and the start of the next flow rate measurement, the flow rate change is judged at fine time intervals, and the occurrence of the flow rate change is detected. The possibility of spilling out can be reduced.

  Further, when the difference between the flow rate detected this time and the flow rate detected in the past is within a certain value, the flow rate is measured by changing the measurement interval for a predetermined time longer. For this reason, when a certain amount of gas is used for a long time, for example, when using a gas stove to stew for a long time, the measurement interval is lengthened, and the power consumption is further reduced when there is no change in the flow rate. can do.

  Further, since the number of times of ultrasonic measurement by the simple measurement mode execution unit 43b is smaller than the number of times of ultrasonic measurement by the normal measurement mode execution unit 43a, it is executed during the measurement interval of the gas flow rate by the normal measurement mode execution unit 43a. The increase in power consumption can be suppressed for the measurement of the flow rate change, and the burden on the battery due to the execution of the flow rate change measurement process can be reduced.

  In addition, the clock frequency for the simple measurement mode execution unit 43b to measure the propagation time is smaller than the clock frequency for the normal measurement mode execution unit 43a to measure the propagation time, so the normal measurement mode execution unit 43a. The increase in power consumption can be suppressed for the measurement of the flow rate change performed during the gas flow rate measurement interval, and the burden on the battery due to the execution of the flow rate change measurement process can be reduced.

  In addition, since the clock frequency for the high-speed measurement mode execution unit 43c to measure the propagation time is smaller than the clock frequency for the regular measurement mode execution unit 43a to measure the propagation time, the use of the gas appliance 10 or the like In this determination, an increase in power consumption can be suppressed, and a burden on the battery due to execution of a determination process such as use of the gas appliance 10 can be reduced.

  Further, whether or not the change in the gas flow rate exceeding the predetermined value has been measured by the simple measurement mode execution unit 43b depends on whether or not the ultrasonic propagation time in the current measurement has changed by a certain value or more than the past propagation time. Judgment based on. For this reason, when the gas flow rate is detected by ultrasonic waves, the change in the gas flow rate can be known from the difference in the propagation time of the ultrasonic waves, and it is not necessary to calculate the gas flow rate itself, thereby reducing the amount of calculation. Therefore, power consumption can be further reduced.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and may be modified without departing from the gist of the present invention. For example, in the present embodiment, the flow rate sensor 41 uses an ultrasonic type. However, the flow rate sensor 41 is not limited to this, and a thermal flow rate using a heater that generates a temperature distribution and a temperature sensor that generates a signal corresponding to the temperature distribution. A sensor may be used. In that case, the heater voltage by the simple measurement mode execution unit 43b is made smaller than the heater voltage by the normal measurement mode execution unit 43a, and the power consumption of the heater when measuring the change in gas flow rate is reduced, thereby measuring the flow rate change. The burden on the battery due to the execution of the process can be reduced. In addition, the heater voltage by the high-speed measurement mode execution unit 43c is made smaller than the heater voltage by the regular measurement mode execution unit 43a, and the power consumption of the heater in the determination process such as the use of the gas appliance 10 is reduced. It is possible to reduce a burden on the battery due to execution of a determination process such as use.

  In the high-speed measurement mode of the present embodiment, the gas pressure is measured by the pressure sensor 42. However, the present invention is not limited to this, and the gas flow rate may be measured by the flow rate sensor 41. This is because the pressure sensor 42 becomes unnecessary and the pressure sensor 42 can be reduced. Note that the measurement accuracy and sensitivity in the high-speed measurement mode for measuring the flow rate need only be those that can measure the waveform of the flow rate vibration, and can be worse than in the normal measurement mode. It is desirable.

  Furthermore, although the high-speed measurement mode of the present embodiment has a measurement interval of about once every 1 millisecond, it is possible to determine whether there is a gas leak, the use of the gas appliance 10 without a governor, or the use of the gas appliance 10 with a governor. It is possible to change the measurement interval as long as it is within a range where a gas pressure or gas flow rate waveform can be obtained. For example, the measurement interval may be 0.1 milliseconds, 10 milliseconds, or 100 milliseconds.

  In the present embodiment, the gas meter 40 has been described as an example of the determination device. However, the present invention is not limited thereto, and only the determination device may be configured by taking out the determination function from the gas meter 40. Furthermore, each execution unit 43a to 43c of the microcomputer 43 or only a part of its functions may be configured as a peripheral analog circuit of the microcomputer 43, or the function of the microcomputer 43 is not a peripheral analog circuit but an ASIC or FPGA. You may be comprised as a circuit module provided as a basic function.

  Moreover, when the flow sensor 41 of the gas meter 40 according to the present embodiment is an ultrasonic type, it is desirable that the number of ultrasonic measurements in the high-speed measurement mode is smaller than the number of ultrasonic measurements in the normal measurement mode. This is because power consumption can be reduced even in the high-speed measurement mode.

  Further, in the present embodiment, the flow rate is measured at a measurement interval of about once every 2 seconds in the normal measurement mode, or about 4 seconds or about when it is determined “YES” in step S13 of FIG. The measurement interval is made longer, such as 10 seconds, but even if the measurement interval is made shorter, such as about 1 second or about 0.5 seconds, when it is judged that a gas appliance with a rapid flow rate change is used. Good.

  Furthermore, in the present embodiment, the flow rate change is measured at a measurement interval of about once every 0.1 seconds in the simple measurement mode. However, the measurement interval is not limited to gas leakage or the use of the gas appliance 10. It can be changed within a range (maximum of about 2 seconds) in which fluctuations in pressure or flow rate immediately after starting can be measured. Here, a shorter measurement interval is preferable, but power consumption increases accordingly. In such a case, when the flow sensor 41 is an ultrasonic sensor, the number of ultrasonic oscillations may be further reduced to reduce power consumption. When the flow sensor 41 is a thermal sensor, the heater voltage may be further increased. It may be reduced to reduce power consumption.

  Furthermore, in the high-speed measurement mode of the present embodiment, when a signal is acquired only from the pressure sensor 42, the flow rate measurement is not performed during a specific time. Therefore, in the present embodiment, flow rate measurement corresponding to the normal measurement mode may be performed during the high-speed measurement mode. For example, in the flowchart of FIG. 10, after instructing execution of the high-speed measurement mode as execution by another program by multitasking in step S <b> 28, the passage of the first predetermined time is monitored by another program (not shown). The program of the flowchart of FIG. 9 that operates the normal measurement mode each time the program is executed may be executed in parallel by different tasks. This is because the integrated flow rate can be obtained without losing the flow rate generated during the specific time.

  In the present embodiment, the high-speed measurement mode execution unit 43c determines whether the gas appliance 10 has been used and whether a gas leak has occurred. However, the present invention is not limited to this, and only one of them is determined. May be. Further, at least one of the pressure waveform and the flow rate waveform measured in the high-speed measurement mode may be analyzed in detail to determine the type of gas leak or gas appliance. For example, a pressure waveform or a flow rate waveform is Fourier transformed to obtain spectrum data. On the other hand, the gas meter 40 stores in advance spectrum data that is basic for each type of gas appliance, and obtains the similarity between the spectrum data obtained by Fourier transform and the stored spectrum data. Based on this, the type of gas leakage or gas appliance may be determined.

  Furthermore, the high-speed measurement mode execution unit 43c according to the present embodiment determines the use of the gas appliance 10 with the governor, the use of the gas appliance 10 without the governor, and the gas leakage based on both the frequency and the amplitude. The use of the gas appliance 10 with the governor may be determined based on only one of the frequency and the amplitude. The frequency includes a lot of the highest components when the gas appliance with a governor 10 is used, followed by the use of the gas appliance 10 without a governor and the gas leakage. For this reason, the high-speed measurement mode execution unit 43c may determine use of the gas appliance 10 with the governor based on only the frequency. Similarly, the amplitude becomes the largest when the gas appliance 10 with the governor is used, followed by the use of the gas appliance 10 without the governor and the gas leakage. For this reason, the high-speed measurement mode execution part 43c may judge use of the gas appliance 10 with a governor etc. based only on an amplitude.

DESCRIPTION OF SYMBOLS 1 ... Gas supply system 10 ... Gas appliance 12 ... Shut-off valve 13 ... Governor 13a ... Governor inner valve 13b ... Nozzle 13c ... Outer wall 13d ... Governor cap 13e ... Diaphragm 13f ... Adjustment spring 13g ... Adjustment screw 13h ... Air hole 14 ... Burner 20 ... Adjuster 31 ... First pipe 32 ... Second pipe 40 ... Gas meter (judgment device)
41 ... Flow rate sensor 42 ... Pressure sensor 43 ... Microcomputer 43a ... Regular measurement mode execution unit (normal measurement mode execution means)
43b ... Simple measurement mode execution unit (simple measurement mode execution means)
43c ... High-speed measurement mode execution section (high-speed measurement mode execution means)
44 ... Drive circuit 44a ... Normal measurement mode drive circuit 44b ... Simple measurement mode drive circuit 44c ... High-speed measurement mode drive circuit

Claims (14)

Regular measurement mode execution means for measuring the gas flow rate in the flow path at predetermined intervals based on the electrical signal from the flow sensor;
Simple measurement that measures a change in gas flow rate exceeding a predetermined value based on an electrical signal from the flow rate sensor after the current flow rate measurement by the normal measurement mode execution means ends and the next flow rate measurement starts. Mode execution means;
When the change in the gas flow rate is measured by the simple measurement mode execution means, the gas flow rate is based on an electric signal from the flow sensor and at least one of the gas pressure in the flow path based on the electric signal from the pressure sensor. High-speed measurement mode execution means for measuring a measurement target and acquiring a measurement target waveform;
A judgment device comprising: The determination device according to claim 1, wherein the high-speed measurement mode execution unit determines at least one of whether a gas appliance has been used and whether a gas leak has occurred based on the waveform of the measurement target. The high-speed measurement mode execution means is a gas leak based on the waveform of the measurement object, a gas appliance having a governor among gas appliances, or a gas appliance having no governor. 3. The determination device according to claim 1, wherein the determination device determines whether or not. The determination device according to any one of claims 1 to 3, wherein the high-speed measurement mode execution unit determines a type of gas appliance based on a waveform of the measurement target. The high-speed measurement mode execution means measures the measurement object for a specific time,
The determination device according to any one of claims 1 to 4, wherein the simple measurement mode execution unit measures a change in the gas flow rate again after a specific time has elapsed. The simple measurement mode execution unit measures a change in the flow rate a plurality of times from the end of the current flow rate measurement by the regular measurement mode execution unit to the start of the next flow rate measurement. The determination apparatus according to any one of claims 1 to 5. The normal measurement mode execution means measures the flow rate by changing the measurement interval for a predetermined time longer when the difference between the flow rate detected this time and the flow rate detected in the past is within a certain value for a plurality of times. The determination device according to any one of claims 1 to 6, wherein: The flow sensor is ultrasonic;
The number of ultrasonic measurements by the simple measurement mode execution unit is less than the number of ultrasonic measurements by the regular measurement mode execution unit. Judgment device. The flow sensor is ultrasonic;
The number of ultrasonic measurements by the high-speed measurement mode execution unit is smaller than the number of ultrasonic measurements by the regular measurement mode execution unit. Judgment device. The flow sensor is ultrasonic;
The clock frequency for measuring the propagation time by the simple measurement mode executing means is smaller than the clock frequency for measuring the propagation time by the normal measurement mode executing means. Item 10. The determination device according to any one of Items 9 to 9. The flow sensor is ultrasonic;
Whether or not a change in gas flow rate exceeding a predetermined value has been measured by the simple measurement mode execution means is based on whether or not the ultrasonic propagation time in the current measurement has changed by a certain value or more than the past propagation time. The determination device according to claim 1, wherein the determination device is determined. The flow sensor is thermal;
The determination apparatus according to any one of claims 1 to 7, wherein a heater voltage by the simple measurement mode execution unit is smaller than a heater voltage by the regular measurement mode execution unit. The flow sensor is thermal;
The heater voltage by the said high-speed measurement mode execution means is made smaller than the heater voltage by the said regular measurement mode execution means. The one of Claims 1-7 and the claim 12 characterized by the above-mentioned. Judgment device. A regular measurement mode execution step of measuring the gas flow rate in the flow path at predetermined intervals based on an electrical signal from the flow sensor;
Simple measurement that measures the change in gas flow rate exceeding a predetermined value based on the electrical signal from the flow rate sensor after the current flow rate measurement in the regular measurement mode execution process is completed until the next flow rate measurement starts. Mode execution process;
When a change in gas flow rate is measured in the simple measurement mode execution step, the gas flow rate is based on an electric signal from the flow sensor and / or a gas pressure in the flow path based on the electric signal from the pressure sensor. High-speed measurement mode execution process that measures the measurement target and obtains the waveform of the measurement target;
The judgment method characterized by comprising.

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