JP2010139282A - Determination device and its pressure value correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a determination device capable of preventing decline of determination accuracy in use determination of a gas apparatus or in gas leak determination, and to provide its pressure value correction method. <P>SOLUTION: A gas meter 40 determines a correction start point and a correction finish point of pressure fluctuation by a start point determination part 47c and a finish point determination part 47d, from among pressure values at each time stored by a storage part 47a. A correction reference value generation part 47e of a microcomputer 47 generates a correction reference value at each time based on the determined correction start point and correction finish point, and a correction part 47f performs correction by subtracting the generated correction reference value at the same time from a pressure value at each time stored by the storage part 47a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a determination device and a pressure value correction method thereof.

Conventionally, a gas supply system for supplying fuel gas to a gas appliance via a gas meter is known. In this gas supply system, a pressure regulating valve is installed at the outlet of the gas supply container. The pressure regulating valve functions to keep the downstream pressure at a constant value of about 2.9 kPa, for example (see, for example, Patent Document 1).
JP 2001-188020 A

  Here, the present applicant has invented the technique of Japanese Patent Application No. 2008-86022. In the present invention, based on the gas pressure, it is determined whether a gas appliance with a governor is used, a gas appliance without a governor is used, and whether a gas leak has occurred.

  However, in the gas supply system described in Patent Document 1, the gas pressure in the gas pipe rises due to temperature changes during the day and at night. That is, if the gas is left unused in the daytime, the temperature in the gas pipe rises and the pressure in the gas pipe from the pressure regulating valve to the gas appliance rises. The pressure rises by about 1 kPa when the temperature rises by about 3 ° C. during the day, and in some cases, the pressure in the gas pipe may reach 4 kPa. And if the gas pressure in a gas pipe rises, when judging whether or not a gas appliance with a governor is used based on the gas pressure as in the technique of Japanese Patent Application No. 2008-86022, the judgment accuracy decreases. I will invite you. 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.

  The present invention has been made to solve such a conventional problem, and the object of the present invention is to make a judgment that can prevent a reduction in judgment accuracy when judging the use of gas appliances or judging gas leaks. An object of the present invention is to provide a device and a pressure value correction method thereof.

  The determination device of the present invention is a determination device for determining use of a gas appliance and gas leakage based on the detected pressure value at each time, and a storage means for storing the detected pressure value at each time; Among the pressure values at each time stored by the storage means, start point determining means for determining a correction start point for pressure fluctuation, and among the pressure values at each time stored by the storage means, a correction end point for pressure fluctuation is determined. Correction reference value generation for generating a correction reference value at each time based on an end point determination means to be determined, a correction start point determined by the start point determination means, and a correction end point determined by the end point determination means And correction means for correcting by subtracting the correction reference value at the same time generated by the correction reference value generation means from the pressure value at each time stored by the storage means. It is characterized in.

  According to this determination apparatus, among the pressure values at each time, a correction start point and a correction end point of pressure fluctuation are obtained, and a correction reference value at each time is obtained based on the correction start point and the correction end point. Correction is performed by subtracting the correction reference value at the same time from the pressure value at each time. Here, when a gas appliance is used or a gas leak occurs, the pressure value decreases from the original pressure to a certain stable pressure. There is a difference in the decreasing component between when the pressure in the pipe is rising and when it is not. Therefore, by determining the correction start point and the correction end point, the start point and end point of the decrease component are determined. Then, the correction reference value at each time is obtained from the start point and the end point of the decreasing component, and is subtracted from the stored pressure value at each time, so that the pressure in the pipe is different depending on whether it is rising or not. This will cancel the decreasing component. Thereby, the pressure value at each time after correction can be made similar between when the pressure in the gas pipe is rising and when it is not. Therefore, it is difficult to be influenced by the lowering component in determining whether to use the gas appliance or determining a gas leak, and it is possible to prevent a decrease in determination accuracy.

  In the determination apparatus of the present invention, it is preferable that the start point determination means determines the correction start point from the pressure value when the pressure fluctuation occurs and the time when the pressure fluctuation occurs.

  According to this determination apparatus, since the correction start point is determined from the pressure value at the time of occurrence of pressure fluctuation and the time at the time of occurrence of pressure fluctuation, the correction start point can be determined without performing complicated calculation. Can do.

  Further, in the determination device of the present invention, the end point determination means includes an average pressure value near a time point when a predetermined pressure detection time has elapsed since the start of pressure detection, and a time point when the pressure detection time has elapsed. Therefore, it is preferable to determine the correction end point.

  According to this determination apparatus, the correction end point is determined from the average pressure value near the time when a predetermined pressure detection time has elapsed since the start of pressure detection and the time when the pressure detection time has elapsed. Therefore, as long as the average value is calculated, the correction end point can be determined without performing a complicated calculation.

  In the determination device of the present invention, the end point determination means includes an end point correction pressure value indicating an average pressure value near the time point when the detected change amount of the pressure becomes a predetermined value or less, and the detected pressure value. However, the correction ends from the time when the end point corrected pressure value first reached after the correction start point or the time when the moving average value of the detected pressure first reached the end point corrected pressure value after the correction start point. It is preferred to determine the point.

  According to this determination device, the end point correction pressure value indicating the average pressure value around the time point when the detected pressure change amount becomes equal to or less than the predetermined value, and the detected pressure value are the first after the correction start point. The correction end point is determined from the time when the end point correction pressure value is reached. Alternatively, the correction end point is determined from the time when the detected moving average value of the pressure first reaches the end point correction pressure value after the correction start point. For this reason, the pressure value in the stable state in which the pressure fluctuation at which the pressure change amount is equal to or less than the predetermined value is almost obtained is obtained as the end correction pressure value, and the time at which the pressure value in the stable state is reached quickly is obtained. Therefore, the point in time when the pressure is decreasing and becoming stable can be determined as the correction end point.

  In the determination device of the present invention, the end point determination means sets an end point correction pressure value indicating an average pressure value near a time point when the detected change amount of the pressure becomes a predetermined value or less and a specific time in advance. The time when the detected pressure value reaches the end point correction pressure value closest to the specific time, or the moving average value of the detected pressure becomes the end point correction pressure value closest to the specific time. It is preferable to determine the correction end point from the reached time.

  According to this determination apparatus, the end point correction pressure value indicating the average pressure value near the time point when the detected change amount of the pressure becomes equal to or less than the predetermined value, the specific time is determined in advance, and the detected pressure value However, the correction end point is determined from the time when the end point correction pressure value is reached closest to the specific time. Alternatively, the correction end point is determined from the time when the moving average value of the detected pressure reaches the end point correction pressure value closest to the specific time. For this reason, the pressure value in a stable state in which there is almost no pressure fluctuation at which the pressure change amount is equal to or less than the predetermined value is obtained as the end correction pressure value. In addition, the time closest to a predetermined specific time among the times when the pressure value reaches a stable state is obtained, and the pressure decreases if the specific time is assumed to be the time when the decrease component is almost eliminated. As a result, it is possible to quickly determine the correction end point as the time when the point is stable.

  In the determination apparatus according to the present invention, the correction reference value generation means may include the start point determination means on the graph showing the correlation between the pressure value stored in the storage means and the time when the pressure value is obtained. A value on a straight line connecting the determined correction start point and the correction end point determined by the end point determination unit is generated as a correction reference value at each time, and the correction unit stores each value stored in the storage unit. It is preferable to correct by subtracting the value on the straight line at the same time from the pressure value at the same time.

  According to this determination apparatus, since a value on a straight line connecting the correction start point and the correction end point is generated as a correction reference value at each time, a graph showing the correlation between the pressure value and the time at which the pressure value was obtained The correction reference value at each time can be obtained only by performing the calculation for obtaining the straight line above, and the correction can be performed with a relatively small amount of calculation.

  In the determination apparatus of the present invention, the correction reference value generation means includes a time at an intermediate point between the correction start point determined by the start point determination means and the correction end point determined by the end point determination means, and On the graph showing the correlation between the pressure value stored by the storage means and the time when the pressure value was obtained, the correction start point, the intermediate point, and the correction end are obtained. A value on a curve connecting points is generated as a correction reference value at each time, and the correction means corrects by subtracting the value on the curve at the same time from the pressure value at each time stored by the storage means. It is preferable to do.

  According to this determination apparatus, since the intermediate point is obtained and the value on the curve connecting the intermediate point in addition to the correction start point and the correction end point is generated as the correction reference value at each time, the pressure value and the pressure value are The correction reference value at each time can be obtained simply by calculating the midpoint and the curve on the graph showing the correlation with the obtained time, and the correction is performed more accurately by removing the lowering component by the curve. be able to.

  Further, in the determination device of the present invention, the correction reference value generation unit is configured to calculate the total pressure value measured between the correction start point determined by the start point determination unit and the correction end point determined by the end point determination unit. An approximate expression that passes through the correction start point is obtained from the data, and a value on the approximate expression is generated as a correction reference value at each time. The correction means calculates the pressure at each time from the pressure value stored at the storage means. It is preferable to correct by subtracting the value on the approximate expression.

  According to this determination apparatus, the value on the approximate expression is generated as the correction reference value at each time, and correction is performed by subtracting the value on the approximate expression at the same time from the pressure value at each time. Appropriate corrections can be made. In particular, although the approximate expression passes through the correction start point, it does not necessarily pass through the correction end point. Therefore, even if there is an error in the time of the correction end point, this deviation can be corrected.

  Further, in the determination apparatus of the present invention, the correction reference value generation means obtains a correction reference value for at least one of the correction start point and after the correction end point, and when calculating the correction reference value before the correction start point, When a value on a straight line that maintains the pressure value at the correction start point on the graph is generated as a correction reference value, and the correction reference value after the correction end point is obtained, the pressure value at the correction end point is maintained on the graph. It is preferable to generate a value on a straight line as a correction reference value.

  According to this determination apparatus, in order to obtain the correction reference value for at least one before the correction start point and after the correction end point, not only the pressure values at the correction start point and the correction end point are corrected, but also before the correction start point. In addition, corrections after the correction end point can also be corrected collectively, which can contribute to an improvement in determination accuracy.

  The pressure value correction method of the present invention is a pressure value correction method for a determination device that determines use of a gas appliance and gas leakage based on the detected pressure value at each time, and detects the pressure at each detected time. A storage step for storing a value, a start point determination step for determining a correction start point for pressure fluctuation among the pressure values stored at each time in the storage step, and a pressure value at each time stored in the storage step Among these, based on the end point determination step for determining the correction end point of pressure fluctuation, the correction start point determined in the start point determination step, and the correction end point determined in the end point determination step, correction at each time The correction reference value generation step for generating a reference value and the correction reference value at the same time generated by the correction reference value generation step are subtracted from the pressure value at each time stored by the storage step. And having a correction step of correcting at Rukoto.

  According to this pressure value correction method, the correction start point and the correction end point of the pressure fluctuation are obtained from the pressure values at each time, and the correction reference value at each time is determined based on the correction start point and the correction end point. Obtained and corrected by subtracting the correction reference value at the same time from the pressure value at each time. Here, when a gas appliance is used or a gas leak occurs, the pressure value decreases from the original pressure to a certain stable pressure. There is a difference in the decreasing component between when the pressure in the pipe is rising and when it is not. Therefore, by determining the correction start point and the correction end point, the start point and end point of the decrease component are determined. Then, the correction reference value at each time is obtained from the start point and the end point of the decreasing component, and is subtracted from the stored pressure value at each time, so that the pressure in the pipe is different depending on whether it is rising or not. This will cancel the decreasing component. Thereby, the pressure value at each time after correction can be made similar between when the pressure in the gas pipe is rising and when it is not. Therefore, it is difficult to be influenced by the lowering component in determining whether to use the gas appliance or determining a gas leak, and it is possible to prevent a decrease in determination accuracy.

  According to the present invention, it is possible to provide a determination device and a pressure value correction method thereof capable of preventing a decrease in determination accuracy in determining whether to use a gas appliance or determining a gas leak.

  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 determination device according to an embodiment of the present invention. The gas supply system 1 supplies fuel gas to each gas appliance 10 such as a stove, a fan heater, a water heater, and a gas stove. The gas supply system 1 includes a plurality of gas appliances 10, a gas supply source regulator 20, and a pipe 31. , 32 and a gas meter (determination device) 40. 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.

  The adjuster 20 adjusts the fuel gas from the upstream to a predetermined pressure and flows it through the first pipe 31. The adjuster 20 has a configuration in which, for example, the fuel gas is adjusted to a pressure of about 2.9 kPa and flows 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. As shown in the figure, the gas meter 40 according to this embodiment includes a flow sensor 41, a pressure sensor 42, and a microcomputer 47.

  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. When the gas meter 40 according to the present embodiment is an ultrasonic type gas meter, the flow sensor 41 is configured by two acoustic transducers 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 and a thermopile that generates a signal corresponding to the temperature distribution.

  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 this embodiment, the signals from the flow sensor 41 and the pressure sensor 42 are directly input to the microcomputer 47 in FIG. 3, but other elements such as an amplifier may be added between the two depending on circumstances. .

  The microcomputer 47 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 47 includes a storage unit (storage unit) 47a and a determination unit 47b. The memory | storage part 47a memorize | stores the pressure value of each time detected through the pressure sensor 42. FIG. The pressure value stored in the storage unit 47a is, for example, data of about 2 seconds at the maximum, and is data measured at a measurement interval of about 0.2 to 5.0 milliseconds. The determination unit 47b determines use of the gas appliance 10 and gas leakage based on the pressure value at each time stored in the storage unit 47a.

  Here, the determination principle of the use of the gas appliance 10 and the gas leakage by the determination unit 47b will be described. FIG. 4 is a graph showing the pressure change when the use of the gas appliance 10 with the governor is started. In FIG. 4, 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 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 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 a 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は初期位置を示している。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 position. This equation indicates that this is a superposition of vibrations of many frequencies f _i = ω _i / 2π.

  FIG. 5 is a graph showing the pressure change when the use of the governorless gas appliance 10 is started. In FIG. 5, the vertical axis represents the pressure change amount (kPa), and the horizontal axis represents the elapsed time (seconds) since the use of the governorless gas appliance 10 was 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. 6 is a schematic diagram showing a state of supply of fuel gas in the governorless gas appliance 10. As shown in FIG. 6, 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. 5 is compared with the pressure waveform shown in FIG. 4, 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. 5 shows vibration in the same manner as the pressure waveform shown in FIG. 4, 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. 5 has a smaller amplitude than the pressure waveform shown in FIG.

  From such characteristics, the determination unit 47b of the microcomputer 47 can determine whether the gas appliance with governor 10 is used or whether the gas appliance 10 without governor is used.

  FIG. 7 is a graph showing a state of pressure change at the time of gas leakage. In FIG. 7, 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. 7, 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 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. The determination unit 47b of the microcomputer 47 can determine whether the gas appliance 10 with the governor is used, the gas appliance 10 without the governor, or the gas leak from the above characteristics.

  However, if the gas is left unused in the daytime, the temperature in the pipes 31 and 32 will rise, and the pressure in the pipes 31 and 32 from the regulator 20 to the gas appliance 10 will rise. The pressure rises by about 1 kPa when the temperature rises by about 3 ° C. during the day, and in some cases, the pressure in the pipes 31 and 32 may reach 4 kPa. When the gas pressure in the pipes 31 and 32 rises, as described with reference to FIGS. 4 to 7, it is determined whether or not a gas appliance with a governor is used based on the gas pressure. In addition, the accuracy of judgment is reduced.

  Here, in the following description, the pressure in the pipes 31 and 32 before the pressure fluctuation, such as before using the gas appliance or before the occurrence of gas leakage, is referred to as a source pressure.

  FIG. 8 is a graph showing pressure waveforms at the start of use of the gas appliance 10 when the source pressure is rising and when it is not rising. When the original pressure is not increased, the pressure value before the start of use of the gas appliance 10 is about 2.95 kPa. When the gas appliance 10 is used, the pressure value becomes about 2.8 kPa after 1 second while showing a predetermined vibration from the start of use. On the other hand, when the original pressure has increased, the pressure value before the start of using the gas appliance 10 is about 3.17 kPa. When the gas appliance 10 is used, the pressure value becomes about 2.8 kPa after 1 second while showing a predetermined vibration from the start of use.

  Thus, the pressure waveform obtained differs between when the source pressure is rising and when it is not rising. From such a difference, when the determination unit 47b determines whether or not the gas appliance with the governor is used, there is a possibility that the determination is erroneous.

  Therefore, in the gas meter 40 according to the present embodiment, the pressure value is corrected. FIG. 3 will be referred to again. As shown in FIG. 3, the microcomputer 47 includes a start point determination unit (start point determination unit) 47 c, an end point determination unit (end point determination unit) 47 d, and a correction reference value generation unit as a configuration for correcting the pressure value. (Correction reference value generation means) 47e and correction section (correction means) 47f are provided.

  Here, when the gas appliance 10 is used, the applicant of the present application has a pressure waveform in a section until the pressure value is stabilized (for example, a section from time “0” to “0.2” in FIG. 8). The present inventors have found that a lowering component that decreases at a certain rate and a specific component are included. The specific component is a fine vibration component when the gas appliance 10 is used, and a component that cannot be clearly described as vibration when a gas leak occurs. Furthermore, the present applicant has found that there is no significant difference in the specific component, although the decrease component differs depending on whether the source pressure is rising or not. Therefore, in the gas meter 40 according to the present embodiment, the configuration of the start point determination unit 47c, the end point determination unit 47d, the correction reference value generation unit 47e, and the correction unit 47f removes the decrease component and leaves the specific component. Thus, the same pressure waveform is obtained when the original pressure increases and when the original pressure does not increase, so that the determination accuracy does not decrease.

  FIG. 3 will be referred to again. The start point determination unit 47c determines a correction start point for pressure fluctuation (that is, the start point of the lowering component) among the pressure values at each time stored in the storage unit 47a. Further, the end point determination unit 47d determines a correction end point of pressure fluctuation (that is, an end point of the decrease component) among the pressure values at each time stored in the storage unit 47a.

  Here, a method for determining the correction start point and the correction end point will be described with reference to FIGS. 9 and 10 are graphs showing the correction start point and the correction end point determined by the start point determination unit 47c and the end point determination unit 47d shown in FIG. 3, and FIG. 9 shows that the original pressure has increased. FIG. 10 shows a case where the source pressure is not increased.

  As shown in FIG. 9 and FIG. 10, the start point determination unit 47c determines the pressure value when the pressure change occurs (3.17 kPA in FIG. 9, 2.95 kPa in FIG. 10) and the time when the pressure change occurs ( Correction start points A1 and A2 are determined from time 0) in both FIGS.

  Specifically, the start point determination unit 47c determines that a pressure change has occurred when the pressure value has changed by a predetermined amount or more within a certain time. Then, for example, an average of pressure values for a predetermined time before the occurrence of the pressure change is calculated, and the pressure value at the time of occurrence of the pressure change (that is, 3.17 kPA in FIG. 9 and 2.95 kPa in FIG. 10) is determined. Also, the start point determination unit 47c determines the time when it is determined that the pressure change has occurred as the time when the pressure change has occurred, or the time when the pressure starts to decrease retroactively from the time when it is determined that the pressure change has occurred And this time is determined as the time when the pressure change occurs. In addition, the determination method of the pressure value at the time of occurrence of a pressure change and the time at the time of occurrence of a pressure change is not limited to the above, and other methods may be used.

  Further, the end point determination unit 47d uses the average pressure value (about 2.82 kPa in both FIG. 9 and FIG. 10) around the time when the amount of change in the pressure stored in the storage unit 47a is equal to or less than a predetermined value as the end point correction pressure. The end point corrected pressure value and the detected pressure value reached the end point corrected pressure value for the first time after the correction start point (near time 0.21 in FIG. 9) or detected. Correction end points C1 and C2 are determined from the time when the moving average value of pressure reaches the end point correction pressure value for the first time after the correction start point (around time 0.13 in FIG. 10).

  This will be described in detail. First, the end point determination unit 47d obtains stable points B1 and B2 prior to determining the correction end points C1 and C2. The stable points B1 and B2 are points where the pressure fluctuations are settled, specifically, the time when the amount of change in pressure within a certain time becomes equal to or less than a predetermined value (about 0.58 seconds in FIG. 9, FIG. 10). , About 0.68 seconds), and an average value of pressure values for a predetermined time before and after that time (about 2.82 kPa in both FIG. 9 and FIG. 10). Then, this average value becomes the end point correction pressure value as it is. That is, the pressure values at the stable points B1 and B2 become the pressure values at the correction end points C1 and C2.

  Further, the end point determination unit 47d determines the time when the pressure value first reaches the end point corrected pressure value (about 2.82 kPa) after the correction start point so as to go back from the stable points B1 and B2. . In the example shown in FIG. 9, this time is around time 0.21. Therefore, the end point determination unit 47d determines the point at which the pressure value is about 2.82 kPa and the time is 0.21 as the correction end point C1.

  Further, as shown in FIG. 10, the end point determination unit 47d obtains the time at which the moving average value of pressure first reaches the end point correction pressure value (about 2.82 kPa) after the correction start point. In the example shown in FIG. 10, this time is around time 0.13. For this reason, the end point determination unit 47d determines the point at which the pressure value is about 2.82 kPa and the time is 0.13 as the correction end point C2.

  Refer to FIG. 3 again. The correction reference value generation unit 47e generates a correction reference value at each time based on the correction start points A1 and A2 and the correction end points C1 and C2. The correction unit 47f performs correction by subtracting the correction reference value at the same time generated by the correction reference value generation unit 47e from the pressure value at each time stored in the storage unit 47a.

  Please refer to FIG. 9 and FIG. Specifically, as shown in FIGS. 9 and 10, the correction reference value generation unit 47 e performs correction on the graph indicating the correlation between the pressure value stored in the storage unit 47 a and the time when the pressure value is obtained. A value on a straight line connecting the start points A1, A2 and the correction end points C1, C2 is generated as a correction reference value. And the correction | amendment part 47f correct | amends by subtracting the value on a straight line from the pressure value in each time memorize | stored by the memory | storage part 47a.

  FIG. 11 is a graph showing the corrected pressure values when the source pressure is rising and when it is not rising. As shown in FIG. 11, the pressure value at each time has a substantially similar waveform by correcting and removing the decrease component. That is, even if the original pressure is increased, the increased amount is cancelled, and the corrected waveform is approximately similar. In this embodiment, the determination unit 47b performs the determination described with reference to FIGS. 4 to 7 based on the corrected pressure waveform as shown in FIG. 11, and the gas appliance 10 with the governor is used. It is determined whether there is a gas appliance 10 without a ganaba, and whether a gas leak has occurred.

  In the above description, the correction reference value generation unit 47e obtains a straight line on the graph. However, this straight line is not limited to the line segment connecting the correction start points A1 and A2 to the correction end points C1 and C2, and FIG. 9 and FIG. As shown in FIG. 10, correction reference values may be obtained for correction start points A1 and A2 and before correction end points C1 and C2. This is because the correction can be performed over a wide range, not from the correction start points A1 and A2 to the correction end points C1 and C2.

  More specifically, when the correction reference value generation unit 47e obtains correction reference values before the correction start points A1 and A2, values on a straight line that maintain pressure values at the correction start points A1 and A2 on the graph. Is generated as the correction reference value, and the correction reference value after the correction end points C1 and C2 is calculated, the value on the straight line that maintains the pressure value at the correction end points C1 and C2 on the graph is generated as the correction reference value. Will be. In the examples shown in FIGS. 9 and 10, the correction reference values are obtained for both the correction start points A1 and A2 and the correction end points C1 and C2 and after, but not limited to this, only one of them is obtained. You may do it.

  The correction method described above is merely an example, and may be as follows. For example, the end point determination unit 47d determines the correction end point from the average pressure value around the time when a predetermined pressure detection time has elapsed since the start of pressure detection, and the time when the pressure detection time has elapsed. You may make it do. More specifically, it is assumed that the pressure detection time is predetermined as about 0.2 seconds. In this case, the end point determination unit 47d obtains an average pressure value in the vicinity of a point when 0.2 seconds have elapsed since the start of pressure detection. Then, a correction end point that satisfies the condition of the average pressure value and the time point of 0.2 seconds is determined.

  Further, the correction reference value generation unit 47e is not limited to the case where the value on the straight line connecting the correction start points A1 and A2 and the correction end points C1 and C2 is generated as the correction reference value on the graph, but the correction start point A1. , A2 and correction end points C1 and C2 may be generated as a correction reference value. In this case, the correction reference value generation unit 47e first obtains an intermediate point from the time at the intermediate point between the correction start points A1 and A2 and the correction end points C1 and C2 and the average pressure value near this time. Next, a curve (for example, a quadratic curve) connecting the correction start points A1 and A2, the intermediate point, and the correction end points C1 and C2 is generated. Then, the correction reference value generation unit 47e sets values on the curve connecting the correction start points A1 and A2, the intermediate point, and the correction end points C1 and C2 as correction reference values at each time. Thus, the correction unit 47f performs correction by subtracting the value on the curve at the same time from the stored pressure value at each time.

  Next, the pressure value correction method of the gas meter 40 according to the present embodiment will be described with reference to a flowchart. FIG. 12 is a flowchart showing a pressure value correction method for the gas meter 40 according to this embodiment.

  As shown in FIG. 12, the memory | storage part 47a of the microcomputer 47 memorize | stores the pressure value detected through the pressure sensor 42 first (S10). Next, the microcomputer 47 determines whether or not the measurement is finished (S11). When it is determined that the measurement is not finished (S11: NO), the storage unit 47a stores the pressure value detected through the pressure sensor 42 again (S10).

  On the other hand, when it is determined that the measurement is finished (S11: YES), the start point determination unit 47c determines the correction start points A1 and A2 as described with reference to FIGS. 9 and 10 (S12). Thereafter, the end point determination unit 47d determines the correction end points C1 and C2 as described with reference to FIGS. 9 and 10 (S13).

  Next, the correction reference value generation unit 47e generates a value on a straight line connecting the correction start points A1 and A2 and the correction end points C1 and C2 on the graph as a correction reference value (S14). In this process, the correction reference value generation unit 47e may calculate a curve after obtaining the intermediate point, and generate a value on the curve as the correction reference value.

  After the generation of the correction reference value, the correction unit 47f subtracts the correction reference value at the same time from the pressure value at each time (S15). Thereafter, the microcomputer 47 determines use of the gas appliance 10 or gas leakage based on the subtracted pressure value data (S16). Thereafter, the microcomputer 47 determines whether or not there is no gas leakage in the process of step S16 (S17).

  If it is determined that there is no gas leakage (S17: YES), the process shown in FIG. 12 ends. On the other hand, if it is not determined that there is no gas leak (S17: NO), that is, if it is determined that there is a gas leak, the microcomputer 47 shuts off the shutoff valve and issues an alarm (S18). Thereafter, the process shown in FIG. 12 ends.

  FIG. 13 is a flowchart showing details of step S16 shown in FIG. 12, and shows processing related to use of the gas appliance 10 and determination of gas leakage. As shown in FIG. 13, first, the microcomputer 47 analyzes the frequency of the waveform of the pressure value subtracted in step S15 of FIG. 12 (S30) and analyzes the amplitude (S31).

  Thereafter, the microcomputer 47 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 S30 (S32). If it is determined that a frequency component equal to or higher than the discriminant value is included (S32: YES), that is, if the frequency is high to some extent as in the pressure waveform shown in FIG. 4, the microcomputer 47 uses the gas appliance 10 with the governor. (S33). Then, the process shown in FIG. 13 ends, and the process proceeds to step S17 in FIG.

  If it is determined that a frequency component equal to or higher than the discriminant value is not included in the waveform (S32: NO), the microcomputer 47 first determines the amplitude value of the first peak (that is, the first amplitude after the pressure changes). The maximum value when the value increases in the positive direction, or the value when the amplitude becomes the maximum in the positive direction throughout the whole) is a predetermined amount to the original pressure (the pressure of “0” on the vertical axis in FIG. 4). It is determined whether or not it is equal to or greater than the added value (S34). If 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 (S34: YES), the microcomputer 47 determines that the gas appliance 10 with the governor is used (S33). Then, the process shown in FIG. 13 ends, and the process proceeds to step S17 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 (S34: NO), the microcomputer 47 determines that the amplitude value of the first mountain is substantially equal to the original pressure. It is determined whether or not (specifically, the original pressure ± the specified value) (S35). When it is determined that the amplitude value of the first peak is substantially equal to the original pressure (S35: YES), the microcomputer 47 determines that the governorless gas appliance 10 is used (S36). Then, the process shown in FIG. 13 ends, and the process proceeds to step S17 in FIG.

  If it is determined that the amplitude value of the first peak is not substantially equal to the original pressure (S35: NO), the microcomputer 47 determines that the amplitude value of the first peak is equal to or less than the value obtained by subtracting a predetermined amount from the original pressure. It is determined whether or not (S37). When it is determined that the amplitude value of the first peak is equal to or less than a value obtained by subtracting a predetermined amount from the original pressure (S37: YES), the microcomputer 47 detects a flow rate that is equal to or greater than a specified amount based on a signal from the flow sensor 41. It is determined whether or not (S38).

  When it is determined that a flow rate exceeding the specified amount is detected (S38: YES), that is, the characteristics of frequency and amplitude due to the use of the gas appliance 10 cannot be obtained, the gas pressure in the flow path is reduced, and the specified amount is obtained. If the above flow rate is detected, the microcomputer 47 determines that there is a gas leak (S39). Then, the process shown in FIG. 13 ends, and the process proceeds to step S17 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 (S37: NO), and when it is determined that the flow rate exceeding the specified amount is not detected (S38: NO). The microcomputer 47 determines that neither the use of the gas appliance 10 nor the gas leakage is applicable (S40). Then, the process shown in FIG. 13 ends, and the process proceeds to step S17 in FIG.

  Note that use of the gas appliance 10 and gas leakage are not limited to those illustrated in FIG. 13, and may be determined by other methods, for example. For example, if the microcomputer 47 determines “YES” in step S32 or step S34, the microcomputer 47 determines that the gas appliance with governor 10 is used, but not limited to this, “YES” in both step S32 and step S34. If it is determined, it may be determined that the gas appliance with governor 10 is used.

  Further, the microcomputer 47 may determine that the governor-equipped gas appliance 10 is used when the attenuation coefficient of the pressure waveform is equal to or less than a predetermined value. Further, the microcomputer 47 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, 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.

  Thus, according to the gas meter 40 and its pressure value correction method according to the present embodiment, the pressure fluctuation correction start points A1 and A2 and the correction end points C1 and C2 are obtained from the pressure values at the respective times. A correction reference value at each time is obtained based on these correction start points A1, A2 and correction end points C1, C2, and correction is performed by subtracting the correction reference value at the same time from the pressure value at each time. Here, when the gas appliance 10 is used or a gas leak occurs, the pressure value decreases from the original pressure to a certain stable pressure. There is a difference in the decreasing component between when the source pressure is rising and when it is not. Therefore, by determining the correction start points A1 and A2 and the correction end points C1 and C2, the start point and end point of the decrease component are determined. Then, the correction reference value at each time is obtained from the starting point and the end point of the decreasing component, and the pressure difference at each time stored is subtracted from the stored pressure value, so that the difference is different between when the original pressure is rising and when it is not. The component will be cancelled. Thereby, the pressure value at each time after correction can be made similar between when the pressure in the gas pipe is rising and when it is not. Therefore, when using the gas appliance 10 or determining the gas leakage, it is difficult to be influenced by the lowering component, and it is possible to prevent the determination accuracy from being lowered.

  Further, in order to determine the correction start points A1 and A2 from the pressure value when the pressure fluctuation occurs and the time when the pressure fluctuation occurs, the correction start points A1 and A2 are determined without performing complicated calculations. be able to. In particular, in this embodiment, since the determination device is built in the gas meter 40, it is possible to contribute to the extension of the battery life by reducing the amount of calculation.

  Further, in order to determine the correction end points C1 and C2 from the average pressure value near the time point when a predetermined pressure detection time has elapsed since the start of pressure detection and the time point when the pressure detection time has elapsed, As long as the average value is calculated, the correction end points C1 and C2 can be determined without performing a complicated calculation. In particular, in this embodiment, since the determination device is built in the gas meter 40, it is possible to contribute to the extension of the battery life by reducing the amount of calculation.

  In addition, the end point correction pressure value indicating the average pressure value near the time point when the detected pressure change amount is equal to or less than the predetermined value, and the detected pressure value are the first end point correction pressure value after the correction start point. The correction end points C1 and C2 are determined from the time at which the value is reached. Alternatively, the correction end points C1, C2 are determined from the time when the detected moving average value of the pressure first reaches the end point correction pressure value after the correction start point. For this reason, the pressure value in the stable state in which the pressure fluctuation at which the pressure change amount is equal to or less than the predetermined value is almost eliminated is obtained as the end correction pressure value, and the time at which the pressure value in the stable state is reached quickly is obtained. Therefore, the time when the pressure is decreasing and becoming stable can be determined as the correction end points C1 and C2.

  Further, since a value on a straight line connecting the correction start points A1, A2 and the correction end points C1, C2 is generated as a correction reference value at each time, the correlation between the pressure value and the time when the pressure value is obtained is shown. The correction reference value at each time can be obtained simply by calculating the straight line on the graph, and correction can be performed with a relatively small amount of calculation.

  Further, in order to obtain an intermediate point and generate a value on a curve connecting the intermediate points in addition to the correction start points A1 and A2 and the correction end points C1 and C2 as a correction reference value at each time, the pressure value and its pressure value The correction reference value at each time can be obtained just by calculating the midpoint and the curve on the graph showing the correlation with the obtained time, and the correction that removes the lowering component more accurately by the curve can be performed. It can be carried out.

  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 pressure value is measured once every millisecond. However, the present invention is not limited to this, and the state in which the pressure sensor 42 is always driven and the pressure is constantly detected, that is, the measurement interval is 0. It may be 1 millisecond.

  In the present embodiment, the determination device exists as an internal configuration of the gas meter 40. However, the determination device is not limited thereto, and the determination device may be configured by being taken out from the gas meter 40.

  In the present embodiment, the correction end points C1 and C2 are determined under the condition that they are closest to the correction start points A1 and A2. However, the present invention is not limited to this, and the condition that the correction end points C1 and C2 are closest to the correction start points A1 and A2 is determined. May be determined in advance, and the correction end points C1 and C2 may be determined by substituting a condition that is closest to the specific time. As shown in FIGS. 9 and 10, the correction end points C1 and C2 can hardly be located in the time zone of 0.3 second transition on the graph. For this reason, it is possible to determine more accurate correction end points C1 and C2 by setting the specific time to 0.2 seconds, for example.

  Specifically, the end point determination unit 47d sets the average pressure value near the time point when the detected amount of change in pressure is equal to or less than a predetermined value as the end point correction pressure value. Then, the end point determination unit 47d ends the correction based on the time when the detected pressure value reaches the end point correction pressure value closest to the specific time (for example, 0.2 seconds) and the end point correction pressure value. Determine the point. Alternatively, the end point determination unit 47d determines from the time when the moving average value of the detected pressure reaches the end point correction pressure value closest to the specific time (for example, 0.2 seconds) and the end point correction pressure value. Determine the correction end point.

  By performing such an operation, a pressure value in a stable state in which there is almost no pressure fluctuation at which the amount of change in pressure is equal to or less than a predetermined value is obtained as an end correction pressure value. In addition, the time closest to the predetermined specific time among the times when the pressure value reaches a stable state is obtained, and the pressure decreases if the specific time is assumed to be the time when the decrease component is almost eliminated. Thus, it is possible to quickly determine the time when the point is stable as the correction end points C1 and C2.

  Further, in the present embodiment, the correction reference value generation unit 47e measures between the correction start points A1 and A2 determined by the start point determination unit 47c and the correction end points C1 and C2 determined by the end point determination unit 47d. An approximate expression that passes through the correction start points A1 and A2 is obtained from the data of all the pressure values that have been generated, and a value on the approximate expression is generated as a correction reference value at each time. The correction unit 47f is stored in the storage unit 47a. Alternatively, the pressure value at each time may be corrected by subtracting the value on the approximate expression at the same time. This is because more appropriate correction can be performed by the approximate expression. In particular, the approximate expression passes through the correction start points A1 and A2, but does not necessarily pass through the correction end points C1 and C2. Therefore, even if there is an error in the time of the correction end points C1 and C2, this deviation should be corrected. Because you can.

Here, an example of an approximate expression calculation method will be described. FIG. 14 is a conceptual diagram illustrating an example of an approximate expression calculation method. First, the start point determination unit 47c and the end point determination unit 47d obtain the correction start point A1 and the correction end point C1 in the same manner as described above. At this time, the coordinates of the correction start point A1 are set to (0, Ps), and the coordinates of the correction end point C1 are set to (t ₀ , Pe). Note that Ps is the pressure at the start, that is, the original pressure, and Pe is the pressure at the time of stabilization. Also, t ₀ is the first time that the stable pressure is reached. In such a case where the correction start point A1 and the correction end point C1 are obtained, the correction reference value generation unit 47e generates P = Ps− (Ps−Pe) · {1−exp (−t / 0. 632 · t ₀ )} is applied. And the correction | amendment part 47f will correct | amend by subtracting the value P on the type | formula of the attenuation curve at the same time from the pressure value in each time memorize | stored by the memory | storage part 47a.

It is a lineblock diagram of a gas supply system containing a judgment 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 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 graph which shows the pressure waveform at the time of the start of use of the gas appliance in the case where the original pressure is rising and the case where it is not rising. FIG. 4 is a graph showing a correction start point and a correction end point determined by the start point determination unit and the end point determination unit shown in FIG. 3, and shows a case where the pressure in the pipe is rising. FIG. 4 is a graph showing a correction start point and a correction end point determined by a correction start point determination unit and an end point determination unit shown in FIG. 3, and shows a case where the source pressure has not increased. It is a graph which shows the pressure value after correction | amendment in the case where the original pressure is rising, and the case where it is not rising. It is a flowchart which shows the pressure value correction method of the gas meter which concerns on this embodiment. It is a flowchart which shows the detail of step S16 shown in FIG. 12, and has shown the process regarding use of a gas appliance and a gas leak determination. It is a conceptual diagram which shows an example of the calculation method of an approximate expression.

Explanation of symbols

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 sensor 42 ... Pressure sensor 47 ... Microcomputer 47a ... Storage section (storage means)
47b ... determination unit 47c ... start point determination unit (start point determination means)
47d: End point determination unit (end point determination means)
47e ... Correction reference value generation unit (correction reference value generation means)
47f ... Correction unit (correction means)

Claims (10)

A determination device that determines use of gas appliances and gas leakage based on the detected pressure value at each time,
Storage means for storing the detected pressure value at each time;
Among the pressure values at each time stored by the storage means, start point determining means for determining a correction start point for pressure fluctuation;
Of the pressure values at each time stored by the storage means, an end point determining means for determining a correction end point of pressure fluctuation;
Correction reference value generation means for generating a correction reference value at each time based on the correction start point determined by the start point determination means and the correction end point determined by the end point determination means;
Correction means for correcting by subtracting the correction reference value at the same time generated by the correction reference value generation means from the pressure value at each time stored by the storage means;
A judgment device comprising: The determination device according to claim 1, wherein the start point determination unit determines a correction start point from a pressure value when the pressure fluctuation occurs and a time when the pressure fluctuation occurs. The end point determination means determines a correction end point from an average pressure value near a point when a predetermined pressure detection time has elapsed since the start of pressure detection and a time when the pressure detection time has elapsed. The determination device according to claim 1, wherein: The end point determination means includes an end point correction pressure value indicating an average pressure value near a time point when the detected change amount of pressure becomes equal to or less than a predetermined value, and a detected pressure value after the correction start point. Determining the correction end point from the time when the end point correction pressure value is reached or the time when the moving average value of the detected pressure first reaches the end point correction pressure value after the correction start point. The determination apparatus according to claim 1, wherein the determination apparatus is characterized. The end point determination means determines an end point correction pressure value indicating an average pressure value near the time point when the detected amount of change in pressure becomes equal to or less than a predetermined value, a specific time in advance, and the detected pressure value Is the time when the end point correction pressure value is reached closest to the specific time, or the time when the moving average value of the detected pressure reaches the end point correction pressure value closest to the specific time, The determination device according to claim 1, wherein a correction end point is determined. The correction reference value generation unit is configured to display the correction start point determined by the start point determination unit and the end point on a graph indicating a correlation between the pressure value stored in the storage unit and the time when the pressure value is obtained. A value on a straight line connecting the correction end point determined by the point determination means is generated as a correction reference value at each time,
6. The correction unit according to claim 1, wherein the correction unit corrects the pressure value at each time stored by the storage unit by subtracting the value on the straight line at the same time. Determining device described in 1. The correction reference value generation means is based on a time at an intermediate point between the correction start point determined by the start point determination means and the correction end point determined by the end point determination means, and an average pressure value around this time. On the graph showing the correlation between the pressure value stored by the storage means and the time at which the pressure value was obtained, the intermediate point is obtained and the values on the curve connecting the correction start point, the intermediate point and the correction end point Generate as a correction reference value at time,
6. The correction unit according to claim 1, wherein the correction unit performs correction by subtracting a value on the curve at the same time from a pressure value at each time stored by the storage unit. Determining device described in 1. The correction reference value generation unit is configured to start the correction from data of all pressure values measured between the correction start point determined by the start point determination unit and the correction end point determined by the end point determination unit. Find an approximate expression that passes through the points, and generate a value on this approximate expression as the correction reference value at each time.
The correction means corrects the pressure value at each time stored by the storage means by subtracting the value on the approximate expression at the same time. Judgment device given in the paragraph. The correction reference value generation means obtains a correction reference value for at least one of the correction start point and the correction end point, and when calculating the correction reference value before the correction start point, When a value on a straight line that maintains the pressure value at the correction start point is generated as a correction reference value, and the correction reference value after the correction end point is obtained, the pressure value at the correction end point is maintained on the graph. The determination apparatus according to claim 6, wherein a value on a straight line is generated as a correction reference value. A pressure value correction method for a determination device that determines use of a gas appliance and gas leakage based on a detected pressure value at each time,
A storage step of storing the detected pressure value at each time;
Of the pressure values at each time stored in the storage step, a start point determining step for determining a correction start point for pressure fluctuation;
Of the pressure values at each time stored in the storage step, an end point determination step for determining a correction end point of pressure fluctuation;
A correction reference value generation step for generating a correction reference value at each time based on the correction start point determined in the start point determination step and the correction end point determined in the end point determination step;
A correction step of correcting by subtracting the correction reference value at the same time generated by the correction reference value generation step from the pressure value at each time stored by the storage step;
A pressure value correction method for a determination apparatus, comprising:

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