JP2011099702A - Device and method for determination - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for determination which enable improvement in determination accuracy. <P>SOLUTION: A gas meter 40 is equipped with a determination part 43. The determination part 43 is equipped with a first determination part 43a which determines at least either of gas leakage and a gas appliance 10 being used from a waveform obtained in a minute time from the time of a change of at least either of a gas flow and gas pressure, a second determination part 43b which determines the gas appliance 10 being used from a waveform pattern of the gas flow obtained in a longer time than the minute time, and a selection part 43c which selects one of a first state wherein the first determination part 43a alone is made to function, a second state wherein the second determination part 43b alone is made to function and a third state wherein both of the first and second determination parts 43a and 43b are made to function. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, there has been proposed a gas appliance determination device that determines a gas appliance being used based on a flow rate waveform pattern detected by a flow sensor. In this gas appliance determination device, for example, the waveform pattern of the flow rate for each gas appliance is stored in advance, the waveform pattern from the start to the end of use of the gas appliance is acquired, and the acquired waveform pattern and the stored waveform pattern Match with. And in a gas appliance determination apparatus, the used gas appliance will be judged by the result of matching (for example, refer patent documents 1 and 2).

JP 2003-148728 A JP 2007-93459 A

  In addition, the present inventors have acquired a waveform in a minute time (for example, a maximum of 2 seconds) after a change in gas pressure or gas flow rate by high-speed sampling, and a novel device for judging a gas appliance from the obtained waveform characteristics in the minute time A gas appliance judgment device is being developed. Moreover, in this gas appliance judgment apparatus, it is judged also about the gas leak from the characteristic of the waveform in minute time. According to this gas appliance determination device, it is possible to determine a gas appliance to be used and a gas leak by acquiring data in a minute time, and to make a quick determination.

  However, in the new gas appliance determination device developed by the present inventors, the waveform in a minute time is sampled at a high speed, so that the waveform is disturbed, such as when instantaneous noise is superimposed on the waveform, and the gas appliance used In addition, there is a possibility that the judgment accuracy of the gas leak is lowered.

  In addition, in this specification, although the new gas appliance judgment apparatus under development is demonstrated, this description does not admit publicity about a new gas appliance judgment apparatus.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a determination device and a determination method capable of improving the determination accuracy. .

  The determination apparatus of the present invention includes first determination means for determining at least one of a gas leak and a used gas appliance from a waveform obtained during a minute time from a change in at least one of a gas flow rate and a gas pressure, and the minute time A second determination unit that determines a gas apparatus to be used from a waveform pattern of a gas flow rate obtained in a longer time, a first state in which only the first determination unit functions, and a second state in which only the second determination unit functions. Selecting means for selecting one of two states and a third state in which both the first and second determining means function.

  According to this determination apparatus, at least one of a gas leak and a gas appliance to be used is determined from a waveform obtained during a minute time from the time when at least one of the gas flow rate and gas pressure changes, and the flow rate from when the gas flow rate changes. The gas appliance to be used is determined by matching the waveform pattern of the above and the memory pattern stored in advance for each gas appliance. Then, one of a first state in which only the former is functioned, a second state in which only the latter is functioned, and a third state in which both are functioned is selected. For this reason, when it is difficult for the former function to judge a gas leak or a gas appliance to be used due to noise or the like, the latter function or both functions can be executed to improve the judgment accuracy.

  In the determination device of the present invention, it is preferable that the selection unit selects the first state in an initial state and selects the second state or the third state when a predetermined condition is satisfied.

  According to this determination apparatus, in order to select the first state in the initial state and select the second state or the third state when the predetermined condition is satisfied, the first determination is executed from the waveform of the minute time initially. In addition to enabling quick determination by the determination means, and when the predetermined condition is satisfied due to noise or the like and the determination by the first determination means becomes difficult, the determination accuracy is improved only by the second determination means or both. Can do. Therefore, the determination accuracy can be improved more quickly.

  In the determination apparatus of the present invention, it is preferable that the selection unit selects the first state when the predetermined condition is not satisfied after the predetermined condition is satisfied.

  According to this determination apparatus, when the predetermined condition is not satisfied and the condition is not satisfied, the first state is selected, so that the first determination means capable of determining as quickly as possible is made to function, and the determination can be made more quickly. Can do.

  Further, in the determination device of the present invention, the selection means is configured to perform the second state when the change in the gas flow rate is less than the second specified value even though the change in the gas pressure is equal to or higher than the first specified value. Is preferably selected.

  According to this determination device, the second state is selected when the change in the gas flow rate is less than the second specified value despite the change in the gas pressure being equal to or higher than the first specified value. In this case, the pressure fluctuation is large but the flow fluctuation is small. Usually, pressure fluctuations and flow fluctuations are correlated, and the occurrence of such a phenomenon is considered noise. When noise is generated, the determination accuracy tends to be reduced by the first determination means that performs determination based on a waveform of a minute time. For this reason, by selecting the second state, it is possible to improve the determination accuracy by performing the determination by the second determination unit that determines from a relatively long-time waveform.

  In the determination device of the present invention, it is preferable that the selection unit selects the third state when it is determined that a gas appliance having a gas flow rate or gas pressure amplitude of a predetermined value or more is used.

  According to this determination apparatus, when it is determined that a gas appliance having a gas flow rate or gas pressure amplitude of a predetermined value or more is used, the third state is selected. Here, when a gas appliance having a gas flow rate or gas pressure amplitude of a predetermined value or more is used, even if a gas appliance having a small gas flow rate or gas pressure amplitude is used, the gas appliance having a large amplitude waveform. This makes it difficult to make a judgment by the first judging means. However, since it is unclear whether or not a gas appliance having a small gas flow rate or gas pressure amplitude is used after a gas appliance having a gas flow rate or gas pressure amplitude of a predetermined value or more is used, the third state is The second determination means for making a determination from a relatively long time waveform is made to function without stopping the function of the first determination means. Thereby, even if the waveform of the gas appliance with a small amplitude is buried, by using the second determination means that makes a determination from the waveform for a relatively long time, the use of the gas appliance with a small amplitude can be determined, Judgment accuracy can be improved.

  Further, in the determination device of the present invention, the selection means determines that the gas instrument having a gas flow rate or gas pressure amplitude of a predetermined value or more is used by the first determination means, and uses the gas instrument. When the gas flow rate after the determination is stable and the flow rate value decreased after the stabilization exceeds zero, the third state is selected and the second determination unit is made to function, and the second determination unit is configured to operate the gas flow rate or the gas pressure. It is preferable to determine the used gas appliance based on the waveform pattern of the flow rate after the gas appliance having the amplitude of is not less than a predetermined value.

  According to this determination apparatus, it is determined by the first determination means that a gas appliance having a gas flow rate or gas pressure amplitude of a predetermined value or more is used, and the gas flow rate is stabilized after the use of the gas appliance is determined, When the flow rate value decreased after stabilization exceeds zero, the third state is selected and the second determination means is made to function. Here, when the gas flow rate is stable and the flow rate value decreased after stabilization exceeds zero, the use of another gas appliance is started and continued until one gas appliance starts and ends. It is assumed that In this case, the used gas appliance is determined by causing the second determination means to function. At this time, the used gas appliance is determined based on the waveform pattern of the flow rate after the gas appliance having a gas flow rate or gas pressure amplitude of a predetermined value or more is used. Thereby, even if it is unclear when another gas appliance has started to be used, it is possible to determine another gas appliance to be used.

  Further, in the determination device of the present invention, the selection means determines that the gas instrument having a gas flow rate or gas pressure amplitude of a predetermined value or more is used by the first determination means, and uses the gas instrument. When the gas flow rate after the determination is stable and the flow rate value decreased after the stabilization is zero, it is preferable to select the first state without selecting the third state.

  According to this determination apparatus, even if a gas appliance having a large amplitude is used, if the flow rate value becomes zero when the flow rate subsequently decreases, it can be estimated that the gas appliance having a large amplitude is simply used and stopped. Therefore, it is not necessary to make the second determining means function. Therefore, power consumption can be suppressed without unnecessarily increasing the processing load.

  In addition, the determination method of the present invention includes a first determination step of determining at least one of a gas leak and a gas appliance to be used from a waveform obtained during a minute time from a change in at least one of a gas flow rate and a gas pressure, A second determination step of determining a gas appliance to be used by matching a waveform pattern of a flow rate from the time of a flow rate change and a memory pattern stored in advance for each gas appliance; a first state for executing the first determination step; And a selection step of selecting one of a second state in which the second determination step is executed and a third state in which both the first and second determination steps are executed.

  According to this determination method, at least one of a gas leak and a gas appliance to be used is determined from a waveform obtained during a minute time from when at least one of the gas flow rate and gas pressure changes, and the flow rate from when the gas flow rate changes. The gas appliance to be used is determined by matching the waveform pattern of the above and the memory pattern stored in advance for each gas appliance. Then, one of a first state in which only the former is functioned, a second state in which only the latter is functioned, and a third state in which both are functioned is selected. For this reason, when it is difficult for the former function to judge a gas leak or a gas appliance to be used due to noise or the like, the latter function or both functions can be executed to improve the judgment accuracy.

  According to the present invention, it is possible to provide a determination device and a determination method capable of improving determination accuracy.

It is a lineblock diagram of a gas supply system containing a judgment device concerning an embodiment of the present invention. It is a block diagram which shows the detail of the gas meter shown in FIG. It is a flowchart which shows operation | movement of the selection part shown in FIG. It is a figure which shows an example of the waveform obtained during the micro time immediately after a gas appliance is used. It is a figure which shows an example of a waveform when a gas appliance with a small amplitude is used while using a gas appliance with a large amplitude, wherein (a) shows a combined waveform by using both gas appliances, (b) The waveform of only a gas appliance with a large amplitude is shown, and (c) shows the waveform of only a gas appliance with a small amplitude. It is a figure which shows the outline of the gas leak vibration waveform produced | generated by the production | generation part shown in FIG. It is a figure which shows the mode of a pressure fluctuation | variation, Comprising: (a) shows the pressure change at the time of gas leak, (b) has shown the pressure change at the time of gas appliance use. It is a graph which shows continuous NCC at the time of gas leak. It is a graph which shows continuous NCC at the time of water heater use. It is a graph which shows continuous NCC at the time of floor heating use. It is a flowchart which shows an example of a process of the 1st judgment part shown in FIG. It is a flowchart which shows an example of a process of the 2nd judgment part shown in FIG. 2, Comprising: The process in a 2nd state is shown. It is a flowchart which shows an example of a process of the 2nd judgment part shown in FIG. 2, Comprising: The process in a 3rd state is shown. It is a flowchart which shows operation | movement of the switching part which concerns on 2nd Embodiment. It is a block diagram which shows the detail of the gas meter which concerns on 3rd Embodiment. It is a graph which shows the spectrum data obtained by Fourier-transforming the pressure waveform when a gas leak generate | occur | produces. It is a graph which shows the spectrum data obtained by Fourier-transforming the pressure waveform when a table stove is used. It is a graph which shows the spectrum data obtained by Fourier-transforming the pressure waveform when a gas stove is used. It is a graph which shows the spectrum data obtained by Fourier-transforming the pressure waveform when a water heater is used. It is a graph which shows the spectrum data obtained by Fourier-transforming the pressure waveform when a fan heater is used. It is a flowchart which shows operation | movement of the 1st judgment part which concerns on 3rd Embodiment.

  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 a fuel gas to each gas appliance 10 such as a gas stove, a fan heater, a water heater, a floor heater, and a table stove. The gas supply system 1 includes a plurality of gas appliances 10 and a gas supply source regulator. 20, pipes 31 and 32, and a gas meter (judgment 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 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.

  FIG. 2 is a configuration diagram showing details of the gas meter 40 shown in FIG. As shown in FIG. 2, the gas meter 40 includes a flow sensor 41, a pressure sensor 42, a determination unit 43, a trigger signal generation unit 44, a generation unit 45, a similarity transition storage unit 46, and a waveform pattern storage unit 47. And have. The flow sensor 41 outputs a measurement value signal corresponding to the gas flow rate in the flow path of the gas meter 40. The pressure sensor 42 outputs a measurement value signal corresponding to the gas pressure in the flow path of the gas meter 40.

  Based on at least one of the gas flow rate detected based on the signal from the flow rate sensor 41 and the gas pressure detected based on the signal from the pressure sensor 42, the determination unit 43 performs at least one of the gas leakage and the used gas appliance 10. One of them is judged. Such a determination unit 43 includes a first determination unit (first determination unit) 43a, a second determination unit (second determination unit) 43b, and a selection unit (selection unit) 43c.

  The 1st judgment part 43a judges at least one of a gas leak and a use gas appliance from the waveform acquired in the minute time from the time of the change of at least one of a gas flow rate and a gas pressure. Here, the minute time is, for example, a time within a few seconds (2 seconds at the maximum), and the first determination unit 43a determines the gas leak and the used gas appliance 10 from the waveform obtained within the time within a few seconds.

  The 2nd judgment part 43b judges a use gas appliance from the waveform pattern of the gas flow rate obtained in time longer than micro time. In particular, in the present embodiment, the second determination unit 43b is used by matching a flow rate waveform pattern obtained during a time longer than a minute time from when the gas flow rate is changed with a memory pattern stored in advance for each gas appliance. The gas appliance 10 is determined. Here, the waveform pattern includes at least the gas flow rate when the flow rate changes and the gas flow rate after a predetermined time after the flow rate change. Furthermore, the gas flow rate when it is determined that use of the gas appliance 10 is stopped may be included. In addition, the 2nd judgment part 43b may have a function to judge that it is a gas leak, when the use gas appliance 10 cannot be judged.

  The selection unit 43c has a first state in which only the first determination unit 43a functions, a second state in which only the second determination unit 43b functions, and a third state in which both the first and second determination units 43a and 43b function. One of the states is selected. In particular, the selection unit 43c selects the first state in the initial state, causes only the first determination unit 43a to function, selects the second state or the third state when a predetermined condition is satisfied, and selects only the second determination unit 43b. Or function both the first and second determination units 43a and 43b.

  Next, the operation of the selection unit 43c and predetermined conditions will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the selection unit 43c shown in FIG. First, the selection unit 43c selects the first state in the initial state and causes only the first determination unit 43a to function. And the judgment part 43 judges whether noise is large based on the signal from the flow sensor 41 and the pressure sensor 42 (S1).

  Specifically, noise tends to increase when using a neighboring gas appliance or using a nearby commercial on / off control appliance. When the gas appliance 10 of the adjacent house is used and the amplitude of the gas flow rate or the gas pressure is large for the gas appliance 10, vibration due to the amplitude is transmitted through the flow path and the flow sensor 41 and the pressure sensor 42 in the gas meter 40. The measurement value will be affected. That is, noise increases. More specifically, in the above case, the measurement value of the flow sensor 41 has little influence, but the measurement value of the pressure sensor 42 tends to have a large influence. Similarly, when using a nearby commercial on / off control device, the measurement value of the flow sensor 41 is less affected, but the measurement value of the pressure sensor 42 tends to increase.

  Accordingly, the determination unit 43 determines that the noise is large when the change in the gas flow rate is less than the second specified value despite the change in the gas pressure being equal to or greater than the first specified value (S1: YES). The selection unit 43c selects the second state (S2). Thereby, the function of the 1st judgment part 43a is stopped, and only the 2nd judgment part 43b is functioned. Then, the process shown in FIG. 3 ends.

  Here, the reason for selecting the second state will be described. FIG. 4 is a diagram illustrating an example of a waveform obtained during a minute time immediately after the gas appliance 10 is used. As shown in FIG. 4, when the gas appliance 10 is used, it tends to exhibit an amplitude of about 0.1 kPa or less at a specific frequency during a minute time. Moreover, this amplitude and frequency have the characteristic for every gas appliance 10 used. The 1st judgment part 43a judges the used gas appliance 10 based on the amplitude and frequency of the waveform in micro time. However, when the noise increases, the waveform is disturbed, for example, a change of 0.1 kPa or more occurs, making it difficult to determine the gas appliance 10 to be used.

  On the other hand, the 2nd judgment part 43b judges use gas appliance 10 from a flow pattern of a waveform for a comparatively long time. In particular, the flow rate value when using a gas appliance is relatively large, such as 50 L / h or more, and is not easily affected by noise. Therefore, when the noise is large, it can be said that the second determination unit 43b has higher determination accuracy than the first determination unit 43a. Therefore, the selection unit 43c selects the second state, stops the function of the first determination unit 43a, and causes only the second determination unit 43b to function.

  FIG. 3 will be referred to again. The determination unit 43 determines that the noise is not large (S1: NO), and determines whether the gas appliance 10 having a gas flow rate or gas pressure amplitude of a predetermined value or more is used (S3). When it is determined that the gas appliance 10 having the gas flow rate or the gas pressure amplitude equal to or larger than the predetermined value is used (S3: YES), the selection unit 43c selects the third state (S4), and the first and second determination units. Both 43a and 43b are made to function. Then, the process shown in FIG. 3 ends. On the other hand, when it is determined that the gas appliance 10 having the gas flow rate or the gas pressure amplitude not smaller than the predetermined value is used (S3: NO), the selection unit 43c selects the first state (S5), and the first determination is made. Only the part 43a is caused to function. Then, the process shown in FIG. 3 ends.

  Here, the reason for selecting the third state will be described. FIG. 5 is a diagram illustrating an example of a waveform when the gas appliance 10 having a small amplitude is used while the gas appliance 10 having a large amplitude is used. In FIG. 5, (a) shows the combined waveform when both gas appliances are used, (b) shows the waveform of only the gas appliance 10 with a large amplitude, and (c) shows only the gas appliance 10 with a small amplitude. The waveform is shown.

  As shown in FIG. 5A, it is assumed that a water heater (an example of a gas appliance 10 having a large amplitude) is started to be used at time 0. Then, it is assumed that the gas table (an example of the gas appliance 10 having a small amplitude) starts to be used at time t1. Then, it is assumed that the hot water heater is stopped at time t2. In this case, the flow rate rises from time 0 and shows an amplitude at the flow rate value a1. And the flow rate maintains the value a3 with the use stop of the water heater at time t2.

  When this is disassembled, FIG. 5 (b) and FIG. 5 (c) are obtained. Specifically, the flow rate of only the water heater shows an increase from time 0 and shows an amplitude at the flow rate value a2. After time t2, the flow rate value “0” is indicated. Further, the flow rate of only the gas table increases from time t1, and maintains the flow rate value a3. The flow waveform in FIG. 5A is a combination of FIG. 5B and FIG.

  And in the waveform of Fig.5 (a), it becomes difficult to observe a waveform as shown in FIG. 4 about a gas table. That is, the use of the gas appliance 10 having a large amplitude as the water heater from time 0 causes the waveform of the gas table to be buried, making it difficult to observe the waveform as shown in FIG. For this reason, it becomes difficult for the first determination unit 43a to determine the use of the gas table.

  However, since the 2nd judgment part 43b judges the gas appliance 10 to be used from the waveform pattern of the flow for a comparatively long time, it can judge the gas appliance 10 also in such a condition. More specifically, the second determination unit 43b subtracts the waveform shown in FIG. 5B from the waveform shown in FIG. 5A to obtain the waveform shown in FIG. And the 2nd judgment part 43b judges use of a gas table from the waveform of FIG.5 (c).

  Note that the waveform of the water heater to be subtracted (the waveform of FIG. 5B) is stored in the waveform pattern storage unit 47 as described later.

  FIG. 3 will be referred to again. As described above, the selection unit 43c selects the first to third states. Since the process shown in FIG. 3 is repeatedly executed, the selection unit 43c selects the first state when the predetermined condition is not satisfied (that is, “NO” in both steps S1 and S3), and the first determination unit 43a. Will only work. As described above, since the first determination unit 43a determines the gas leak or the gas appliance 10 to be used from the waveform obtained during the minute time, it can make a quick determination. Therefore, the selection unit 43c basically selects the first state so that only the first determination unit 43a functions.

  The details of the determination unit 43 will be described together with the trigger signal generation unit 44, the generation unit 45, the similarity transition storage unit 46, and the waveform pattern storage unit 47 with reference to FIG. The trigger signal generator 44 detects a change in gas flow rate or gas pressure and outputs a trigger signal. For example, the trigger signal generator 44 includes a differentiation circuit, and detects a change greater than a predetermined value by the differentiation circuit.

  The trigger signal is input to the sensors 41 and 42 and the determination unit 43. When the trigger signal is input, the determination unit 43 shortens the sampling time and measures the waveform in a minute time in detail. That is, high-speed sampling is performed in order to make the determination by the first determination unit 43a accurate. In addition, when a trigger signal is input, each of the sensors 41 and 42 operates in accordance with high speed sampling. Note that the drive current of the sensors 41 and 42 in the normal state may be reduced, and the drive current may be increased to the normal current after the trigger signal is input.

  The generation unit 45 generates a gas leak vibration waveform when it is assumed that a gas leak has occurred. The first determination unit 43a determines gas leakage based on the gas leakage vibration waveform generated by the generation unit 45.

  FIG. 6 is a diagram showing an outline of a gas leakage vibration waveform generated by the generation unit 45 shown in FIG. As illustrated in FIG. 6, the generation unit 45 generates a gas leak vibration waveform that vibrates while the pressure decreases as time passes. This gas leakage vibration waveform is a waveform generated based on a second-order delay step response equation including the frequency, gain, and damping ratio of the damped vibration. Here, the present inventors have found that vibrations occur in the measured values of pressure and flow rate in a very short time immediately after the occurrence of gas leakage. For this reason, the generation unit 45 generates a gas leak vibration waveform based on a second-order delay step response formula as information necessary for the gas leak determination, and the first determination unit 43a is generated by the generation unit 45. The occurrence of gas leakage is determined based on the gas leakage vibration waveform.

  In the example illustrated in FIG. 6, the generation unit 45 generates a gas leakage vibration waveform of pressure, but the generation unit 45 is not limited thereto, and may generate a gas leakage vibration waveform that vibrates while the flow rate increases with time. Good. Further, it is desirable that this waveform is also determined based on a second-order delay step response equation.

Reference is again made to FIG. The first determination unit 43 a calculates the transition of the similarity between the input signal waveform from the sensors 41 and 42 in a minute time and the gas leakage vibration waveform generated by the generation unit 45. The similarity transition refers to continuous normal cross correlation (NCC) in the present embodiment. More specifically, the similarity _RNCC is obtained by the following equation (1). The first determination unit 43a obtains the similarity transition (hereinafter referred to as continuous NCC) by continuously calculating the similarity _RNCC according to the equation (1).

  Furthermore, the first determination unit 43a determines the occurrence of gas leakage based on the calculated similarity transition. In particular, in this embodiment, as an example, it is determined that a gas leak has occurred when the representative value of the similarity transition calculated by the first determination unit 43a is equal to or greater than a threshold value. Here, the representative value may be the total degree of similarity or the average value of a specific period of the whole degree of similarity, or the degree of similarity at a specific time after a change in pressure or flow rate occurs. Alternatively, other values may be used.

  Next, with reference to FIG. 7, the pressure change at the time of a gas leak and use of a gas appliance is demonstrated. FIGS. 7A and 7B are diagrams showing the state of pressure fluctuation, in which FIG. 7A shows a pressure change when a gas leaks, and FIG. 7B shows a pressure change when a gas appliance is used. As shown in FIG. 7A, when a gas leak occurs, a waveform that vibrates while the pressure decreases is shown. This waveform has a high correlation with the gas leak vibration waveform generated by the generation unit 45 as shown in FIG. For this reason, the representative value of the similarity transition shows a high value, and the first determination unit 43a determines that a gas leak has occurred.

  FIG. 8 is a graph showing continuous NCC at the time of gas leakage. In FIG. 8, the solid line and the broken line indicate continuous NCC when conditions such as a difference in piping state, a difference in gas leak location, and a difference in gas leak flow rate in each home are different.

  As shown in FIG. 8, the continuous NCC immediately after the occurrence of a pressure change at the time of gas leakage (near time 0 seconds) shows a value of about “0.7” to “0.8”. However, the continuous NCC shows a value of “0.9” or more after time 0.025 seconds. Therefore, the first determination unit 43a determines that a gas leak has occurred when the representative value of the similarity transition calculated by the similarity transition first determination unit 43a is equal to or greater than “0.9”.

  On the other hand, as shown in FIG. 7B, when the gas appliance is used, a vibration waveform different from that at the time of gas leakage is shown. For this reason, this waveform cannot be said to have a high correlation with the gas leakage vibration waveform generated by the generation unit 45 as shown in FIG. 6, and the representative value of the similarity transition does not show a high value. Therefore, the first determination unit 43a determines that no gas leak has occurred, and determines that the gas appliance 10 has been used.

  FIG. 9 is a graph showing continuous NCC when using a water heater, and FIG. 10 is a graph showing continuous NCC when using floor heating. As shown in FIG. 9 and FIG. 10, the continuous NCC immediately after the occurrence of the pressure change when using the gas appliance (near time 0 seconds) shows a value near “1.0”. However, the continuous NCC shows a value lower than “0.9” after time 0.02 seconds, and shows a value much lower than “0.8” after that. Therefore, the first determination unit 43a determines that no gas leakage has occurred when the representative value of the calculated similarity transition is not “0.9” or more.

  In addition, the case where the change of the pressure or the flow rate occurs is almost when the gas leak occurs or when the gas appliance is used. Therefore, the first determination unit 43a determines that the gas appliance 10 is used when the representative value of the calculated similarity transition is not “0.9” or more.

  7 to 10 show the pressure vibration waveform and the continuous NCC based on the pressure vibration waveform, the gas leak determination can be similarly performed for the flow rate. In the following description, gas leak judgment based on the vibration waveform of pressure will be described, but it goes without saying that the same applies to the flow rate.

Next, details of the gas leak determination will be described. If it demonstrates in detail, the production | generation part 45 will produce | generate a gas leak vibration waveform as follows. First, the generation unit 45 stores the following expression (2).

Here, y (t) indicates the amount of change in pressure, K indicates the gain, ω _d indicates the frequency of the damped vibration, and ζ indicates the damping ratio. In particular, the gain K, the damping vibration frequency ω _d , and the damping ratio ζ are obtained from the waveforms actually measured by the pressure sensor 42. Next, these calculation methods will be described with reference to FIG.

The generation unit 45 calculates the frequency ω _{d of the} damped vibration from the following equation (3).

Here, Tp is the overshoot time, and as shown in FIG. 7A, it is the time from the occurrence of pressure change to the first extreme value V1 (minimum value V1). Generator 45, the first extreme V1 is confirmed from the input signal, determine the overshoot time Tp, it calculates the frequency omega _d damped oscillation from equation (3).

The frequency ω _{d of the} damped vibration is not limited to that obtained from the equation (3), but the second extreme value M (maximum point M) or the third extreme value V2 (minimum point) from the time of occurrence of the pressure change. It may be calculated based on V2).

Next, the generation unit 45 calculates the gain K from the following equation (4).

  Since it is such a formula, generation part 45 will calculate gain K from a formula (4), if extreme values V1, M, and V2 are checked from the inputted signal.

  As is clear from FIG. 7A, the gain K can also be obtained from the difference between the pressure value before the pressure change occurs and the pressure value after the pressure change occurs. Therefore, the generation unit 45 may obtain the gain K from the difference when the pressure change occurs and the pressure value becomes a substantially constant value (time 0.4 seconds in FIG. 7A). Further, the generation unit 45 may calculate the gain K in consideration of the fourth and subsequent extreme values from the time of occurrence of the pressure change.

Next, the generation unit 45 calculates the damping ratio ζ from the following equation (5).

  Here, δ is a logarithmic decay rate, and m is the number of periods. In the case of Expression (5), the number of periods m is “0.5”.

  Since it is such a formula, generation part 45 will compute damping ratio ζ from formula (5), if extreme values V1 and M are confirmed from the inputted signal.

As described above, the generation unit 45 calculates the gain K, the frequency ω _{d of the} damped vibration, and the damping ratio ζ, and obtains the vibration waveform expression from Expression (2). And the production | generation part 45 will obtain | require continuous NCC according to Formula (1) from the calculated | required formula and the input pressure waveform.

Here, the generation unit 45 may calculate the frequency ω _{d of the} damped vibration and the damping ratio ζ as follows. That is, the vibration waveform shown in FIG. 7A tends to depend on the flow rate at the time of gas leakage. For this reason, the generation unit 45 stores in advance an equation that includes only the flow rate value as a variable, and substitutes the flow rate value measured by the flow rate sensor 41 into this equation to obtain the frequency ω _{d of the} damping vibration and the damping ratio ζ. You may make it ask.

Specifically, the generation unit 45 obtains the frequency ω _{d of the} damping vibration and the damping ratio ζ from the following formula (6).

Here, L is a flow rate value, and a ₁ , a ₂ , b ₁ , and b ₂ are constants. In this way, the calculation amount may be reduced by obtaining from Expression (6), and the calculation process may be simplified. There is a certain correlation between the flow rate and the pressure. For this reason, instead of the equation (6), an equation including only the pressure value as a variable may be stored, and the frequency ω _{d of the} damping vibration and the damping ratio ζ may be obtained from this equation.

  Furthermore, in this case, the generation unit 45 desirably calculates the gain K from the difference between the pressure value before occurrence of the pressure change and the pressure value after occurrence of the pressure change without calculating the gain K from Expression (4). This is because the amount of calculation can be further reduced.

  Reference is again made to FIG. The first determination unit 43a has a gas appliance determination function in addition to the gas leak determination function described above. Next, the gas appliance determination function will be described.

  As shown in FIGS. 9 and 10, the continuous NCC is different between the water heater and the floor heating. That is, the continuous NCC is different for each gas appliance 10 and represents the characteristics of each gas appliance 10. In this embodiment, the similarity transition storage unit 46 is provided, and the similarity transition storage unit 46 stores continuous NCC data of each gas appliance 10 in advance. That is, the similarity transition storage unit 46 stores continuous NCC data approximated to that shown in FIG. 9 for hot water heaters, and stores continuous NCC data approximated to that shown in FIG. 10 for floor heating. . For other gas appliances 10, the similarity transition storage unit 46 stores continuous NCC data.

  And the 1st judgment part 43a judges that the gas appliance 10 which the continuous NCC data nearest to the calculated continuous NCC among the continuous NCC data memorize | stored by the similarity transition memory | storage part 46 shows was used.

  Next, the second determination unit 43b and the waveform pattern storage unit 47 will be described in detail with reference to FIG. The waveform pattern storage unit 47 stores a flow rate waveform pattern as shown in FIGS. 5B and 5C, for example. That is, the waveform pattern storage unit 47 stores a waveform pattern approximated to that shown in FIG. 5B for the water heater, and stores a waveform pattern approximated to that shown in FIG. 5C for floor heating. is doing. The waveform pattern storage unit 47 also stores waveform patterns for other gas appliances 10.

  And the 2nd judgment part 43b judges that the gas appliance 10 which the waveform pattern nearest to the waveform actually obtained among the waveform patterns memorize | stored by the waveform pattern memory | storage part 47 shows was used. Moreover, the 2nd judgment part 43b judges that it is a gas leak, when it is judged that it is not near about any waveform pattern.

  Next, the operation of the gas meter 40 according to this embodiment will be described. FIG. 11 is a flowchart illustrating an example of processing of the first determination unit 43a illustrated in FIG. As shown in FIG. 11, first, the first determination unit 43a determines whether or not a trigger signal is input from the trigger signal generation unit 44 (S11). If it is determined that the trigger signal has not been input (S11: NO), this process is repeated until it is determined that the trigger signal has been input.

  On the other hand, when it is determined that a trigger signal is input (S11: YES), the first determination unit 43a shortens the sampling time and measures the pressure with the shortened sampling time (S12). At this time, the first determination unit 43a adjusts so as to measure the pressure at intervals of about 1 microsecond. The measurement time is preferably less than 1 second. This is because the vibration waveform is not observed in the time exceeding 1 second. Further, instead of the pressure sampling time, the flow rate sampling time may be shortened.

Then, after the pressure measurement, the generation unit 45 determines the frequency ω _{d of the} damped vibration, the gain K, and the damping ratio ζ (S13). At this time, the generation unit 45 may calculate the frequency ω _{d of the} damped vibration, the gain K, and the damping ratio ζ based on the equations (3) to (5) or may be obtained from the equation (6). Good.

Next, the generating unit 45 generates a gas leakage vibration waveform based on the second-order delay step response equation from the damping vibration frequency ω _d , the gain K, and the damping ratio ζ determined in step S13 (S14). ). At this time, the generation unit 45 generates the gas leakage vibration waveform by substituting the damping vibration frequency ω _d , the gain K, and the damping ratio ζ determined in step S113 into Expression (2).

  And the 1st judgment part 43a calculates continuous NCC from Formula (1) based on the gas leak vibration waveform determined by step S4, and the waveform which consists of a measured value measured in step S12 (S15). . Next, the first determination unit 43a determines a representative value of continuous NCC and determines whether the representative value is equal to or greater than a threshold value (S16).

  When it is determined that the representative value is greater than or equal to the threshold (S16: YES), the first determination unit 43a determines that a gas leak has occurred (S17). Thereafter, the process shown in FIG. 11 ends.

  When it is determined that the representative value is not equal to or greater than the threshold (S16: NO), the first determination unit 43a reads the similarity transition data for each gas appliance from the similarity transition storage unit 46 (S18). Next, the first determination unit 43a identifies the gas N10 that is closest to the continuous NCC calculated in step S15 among the continuous NCC data for each gas appliance read in step S18 (S19). . Then, the process shown in FIG. 11 ends.

  FIG. 12 is a flowchart illustrating an example of processing of the second determination unit 43b illustrated in FIG. 2 and illustrates processing in the second state. As shown in FIG. 12, first, the second determination unit 43b determines whether or not the gas flow rate has increased (S31). When it is determined that the gas flow rate has not increased (S31: NO), this process is repeated until it is determined that the gas flow rate has increased.

  On the other hand, when it is determined that the gas flow rate has increased (S31: YES), the second determination unit 43b stores the gas flow rate (S32). Thereafter, the second determination unit 43b determines whether or not the gas flow rate has decreased (S33). If it is determined that the gas flow rate has not decreased (S33: NO), the process proceeds to step S32.

  When it is determined that the gas flow rate has decreased (S33: YES), the second determination unit 43b reads the waveform pattern for each gas appliance from the waveform pattern storage unit 47 (S34). And the 2nd judgment part 43b specifies the closest thing to the waveform pattern of the gas flow rate memorize | stored in step S32 among the waveform patterns for every gas appliance read in step S34, and judges the gas appliance 10 to be used. (S35). Then, the process shown in FIG. 12 ends.

  In the example shown in FIG. 12, the second determination unit 43b determines the gas appliance 10 to be used after confirming the decrease in the flow rate in step S33. However, the present invention is not limited to this, and confirms the decrease in the gas flow rate. Alternatively, the used gas appliance 10 may be determined by performing waveform pattern matching.

  Next, prior to describing the processing illustrated in FIG. 13, the third state will be described in detail. First, the selection unit 43c selects the third state when the first determination unit 43a determines that the gas appliance 10 having an amplitude greater than or equal to a predetermined value is used. At this time, the stopped second determination unit 43b starts its function. Taking FIG. 5A as an example, the first determination unit 43a functions immediately after time 0 shown in FIG. 5A, and the first determination unit 43a determines the use of the gas appliance 10 having a large amplitude. Then, the 2nd judgment part 43b judges use gas appliance 10 with respect to the waveform of time 0 to t2 going back to time 0.

  FIG. 13 is a flowchart illustrating an example of processing of the second determination unit 43b illustrated in FIG. 2 and illustrates processing in the third state. First, the second determination unit 43b stores the gas flow rate (S41). Thereafter, the second determination unit 43b determines whether or not the gas flow rate has decreased (S42). If it is determined that the gas flow rate has not decreased (S42: NO), the process proceeds to step S41.

  When it is determined that the gas flow rate has decreased (S42: YES), the second determination unit 43b reads the waveform pattern for each gas appliance from the waveform pattern storage unit 47 (S43). At this time, the 2nd judgment part 43b reads the waveform pattern of the use gas appliance 10 judged by the 1st judgment part 43a.

  Thereafter, the second determination unit 43b performs a subtraction process (S44). Referring to FIG. 5 as an example, after the waveform as shown in FIG. 5 (a) is obtained, the second determination unit 43b reads out the waveform pattern of the water heater and reads out the waveform shown in FIG. 5 (a). Subtract waveform pattern.

  Then, the 2nd judgment part 43b reads the waveform pattern for every gas appliance except the waveform pattern read in step S43 (S45). Next, the second determination unit 43b identifies the waveform pattern read out in step S45 that is closest to the waveform obtained by the subtraction process in step S44, and determines the gas appliance 10 to be used (S46). Thereafter, the process shown in FIG. 13 ends.

  As described above, according to the gas meter 40 and the determination method according to the present embodiment, at least one of the gas leakage and the used gas appliance from the waveform obtained during the minute time from the change of at least one of the gas flow rate and the gas pressure. In addition, the gas appliance 10 to be used is determined by matching the waveform pattern of the flow rate from when the gas flow rate is changed with a memory pattern stored in advance for each gas appliance. Then, one of a first state in which only the former is functioned, a second state in which only the latter is functioned, and a third state in which both are functioned is selected. For this reason, when it is difficult to determine the gas leakage or the gas appliance 10 to be used with the former function due to noise or the like, the latter function or both functions can be executed to improve the determination accuracy.

  In addition, since the first state is selected in the initial state and the second state or the third state is selected when a predetermined condition is satisfied, the first determination unit 43a that initially performs a determination from a waveform of a very short time quickly In addition, when the predetermined condition is satisfied due to noise or the like and the determination by the first determination unit 43a becomes difficult, the determination accuracy can be improved only by the second determination unit 43b or both. . Therefore, the determination accuracy can be improved more quickly.

  In addition, when the predetermined condition is not satisfied and the condition is not satisfied, the first state is selected, so that the first determination unit 43a capable of determining as quickly as possible is caused to function, and a more prompt determination can be made.

  Further, the second state is selected when the change in gas flow rate is less than the second specified value despite the change in gas pressure being equal to or greater than the first specified value. In this case, the pressure fluctuation is large but the flow fluctuation is small. Usually, pressure fluctuations and flow fluctuations are correlated, and the occurrence of such a phenomenon is considered noise. When noise is generated, the determination accuracy tends to be reduced in the first determination unit 43a that performs determination based on a waveform of a minute time. Therefore, by selecting the second state, it is possible to improve the determination accuracy by performing the determination by the second determination unit 43b that performs determination from a relatively long-time waveform.

  Further, when it is determined that the gas appliance 10 having a gas flow rate or gas pressure amplitude of a predetermined value or more is used, the third state is selected. Here, when a gas appliance having a gas flow rate or gas pressure amplitude of a predetermined value or more is used, even if a gas appliance 10 having a small gas flow rate or gas pressure amplitude is used, the gas waveform has a large amplitude. It will be buried in the instrument 10, and the judgment by the 1st judgment part 43a will become difficult. However, since it is unclear whether or not the gas instrument 10 having a small gas flow rate or gas pressure amplitude is used after the gas instrument having a gas flow rate or gas pressure amplitude of a predetermined value or more is used, the third state And the second determination unit 43b that makes a determination from a relatively long time waveform is caused to function without stopping the function of the first determination unit 43a. As a result, even if the waveform of the gas appliance 10 having a small amplitude is buried, the use of the gas appliance 10 having a small amplitude is determined by performing the determination using the second determination unit that determines from the waveform for a relatively long time. It is possible to improve the determination accuracy.

  Next, a second embodiment of the present invention will be described. The gas meter 40 and the determination method according to the second embodiment are the same as those of the first embodiment, but the processing contents are partially different. Hereinafter, differences from the first embodiment will be described.

  FIG. 14 is a flowchart showing the operation of the switching unit 43c according to the second embodiment. As shown in FIG. 14, first, the selection unit 43c selects the first state in the initial state, and causes only the first determination unit 43a to function. And the judgment part 43 judges whether noise is large based on the signal from the flow sensor 41 and the pressure sensor 42 (S51). At this time, the determination unit 43 determines that the noise is large when the change in the gas flow rate is less than the second specified value even though the change in the gas pressure is equal to or greater than the first specified value.

  If the change in gas pressure is not less than the first specified value but the change in gas flow rate is less than the second specified value, the determining unit 43 determines that the noise is large (S51: YES), and the selecting unit 43c. Selects the second state (S52). Thereby, the function of the 1st judgment part 43a is stopped, and only the 2nd judgment part 43b is functioned. Then, the process shown in FIG. 14 ends.

  On the other hand, when determining that the noise is not large (S51: NO), the determination unit 43 determines whether the gas appliance 10 having the gas flow rate or the gas pressure amplitude of a predetermined value or more is used (S53). At this time, the first determination unit 43a determines whether or not the gas appliance 10 having the gas flow rate or the gas pressure amplitude equal to or larger than the predetermined value is used. When it is determined that the gas appliance 10 having the gas flow rate or the gas pressure amplitude equal to or larger than the predetermined value is used (S53: YES), the determination unit 43 determines whether or not the gas flow rate is stabilized and then decreased. (S54).

  If it is determined that the gas flow rate is stable and has not decreased after being stabilized (S54: NO), this process is repeated until it is determined that the gas flow rate has decreased. On the other hand, when it is determined that the gas flow rate is stabilized and then decreased (S54: YES), the determination unit 43b determines whether or not the decreased gas flow rate exceeds zero (S55).

  When it is determined that the gas flow rate after the decrease does not exceed zero (S55: NO), that is, when the flow rate value after the decrease is zero, the selection unit 43c selects the first state without selecting the third state. Is selected (S57). Thereafter, the process shown in FIG. 14 ends.

  If it is determined that the gas flow rate after the decrease exceeds zero (S55: YES), the selection unit 43c selects the third state (S56), and causes both the first and second determination units 43a and 43b to function.

  As described above, in the second embodiment, unlike the first embodiment, steps S54 and S555 are added. This is due to the following reason. In the example shown to Fig.5 (a), after using the gas appliance 10 with a large amplitude, the gas appliance 10 with a small amplitude is used. However, even if the gas appliance 10 having a large amplitude is used, the gas appliance 10 having a small amplitude is not always used. For this reason, when it can be estimated that the gas appliance 10 having a small amplitude is not used, the first state is set instead of the third state.

  For example, even if the gas appliance 10 having a large amplitude is used, if the flow rate value becomes zero when the flow rate is reduced thereafter, it can be estimated that the gas appliance 10 having a large amplitude is simply used and stopped. In this case, in the second embodiment, as shown in FIG. 14, “NO” is determined in the step S55, and the selection unit 43c selects the first state. On the other hand, if the gas appliance 10 having a large amplitude is used and the flow rate value exceeds zero when the flow rate is subsequently reduced, the gas appliance 10 having a small amplitude may be used while the gas appliance 10 having a large amplitude is used. Therefore, in the second embodiment, as shown in FIG. 14, “YES” is determined in the step S55, and the selection unit 43c selects the third state.

  Thus, according to the second embodiment, the determination accuracy can be improved as in the first embodiment.

  Furthermore, according to the second embodiment, the first determination unit 43a determines that the gas appliance 10 having the gas flow rate or the gas pressure amplitude equal to or larger than the predetermined value is used, and after the use of the gas appliance 10 is determined. When the gas flow rate is stabilized and the flow rate value decreased after stabilization exceeds zero, the third state is selected and the second determination unit 43b is caused to function. Here, when the gas flow rate is stabilized and the flow rate value decreased after stabilization exceeds zero, the use of another gas device 10 is started and continued until one gas device 10 is started and finished. Is assumed. In this case, the used gas appliance 10 is determined by causing the second determination unit 43b to function. At this time, the used gas appliance 10 is determined based on the waveform pattern of the flow rate after the gas appliance 10 having a gas flow rate or gas pressure amplitude of a predetermined value or more is used. Thereby, even if it is unclear when another gas appliance 10 has started to be used, it is possible to determine another gas appliance 10 to be used.

  Further, it is determined by the first determination unit 43a that the gas appliance 10 having a gas flow rate or gas pressure amplitude equal to or greater than a predetermined value is used, and the gas flow rate is stabilized after the use of the gas appliance 10 is determined. When the decreased flow rate value is zero, the first state is selected without selecting the third state. Thus, even when the gas appliance 10 having a large amplitude is used, it can be estimated that the gas appliance 10 having a large amplitude is simply used and stopped when the flow rate value becomes zero when the flow rate decreases thereafter. Therefore, it is not necessary to make the second determination unit 43b function. Therefore, power consumption can be suppressed without unnecessarily increasing the processing load.

  Next, a third embodiment of the present invention will be described. The gas meter 40 and the determination method according to the third embodiment are the same as those of the first embodiment, but the gas leakage by the first determination unit 43a and the determination method of the used gas appliance 10 are different.

  FIG. 15 is a configuration diagram showing details of the gas meter 40 according to the third embodiment. As shown in FIG. 15, the gas meter 40 according to the third embodiment includes a spectrum data storage unit 48 instead of the generation unit 45 and the similarity transition storage unit 46 of the first embodiment. The spectrum data storage unit 48 performs a Fourier transform on a waveform that is predicted to be obtained in a minute time immediately after the occurrence of a gas leak, and a waveform that is expected to be obtained in a minute time immediately after the use of each gas appliance 10. Spectral data that has undergone Fourier transform is stored.

  FIG. 16 is a graph showing spectrum data obtained by Fourier transforming a pressure waveform when gas leakage occurs, and FIG. 17 is a spectrum obtained by Fourier transforming the pressure waveform when a table stove is used. It is a graph which shows data. FIG. 18 is a graph showing spectral data obtained by Fourier transforming the pressure waveform when the gas stove is used, and FIG. 19 is a graph showing the Fourier transform of the pressure waveform when the water heater is used. FIG. 20 is a graph showing spectrum data obtained, and FIG. 20 is a graph showing spectrum data obtained by Fourier transforming a pressure waveform when the fan heater is used.

  As shown in FIG. 16, when a gas leak occurs, the obtained pressure waveform contains almost no frequency component of 20 Hz or more. As shown in FIG. 17, when a table stove is used, the obtained pressure waveform contains almost no frequency component of 20 Hz or more, but tends to show a large amplitude in the frequency component around 10 Hz. .

  Moreover, as shown in FIGS. 18-20, when a gas stove, a water heater, and a fan heater are used, the obtained pressure waveform tends to show a large amplitude in a frequency component of 20 Hz or more. More specifically, as shown in FIG. 18, when a gas stove is used, the obtained pressure waveform tends to show a large amplitude in a frequency component of about 20 to 40 Hz. As shown in FIG. 19, when a water heater is used, the obtained pressure waveform tends to show a large amplitude in a frequency component of 70 Hz or more in addition to a frequency component of about 20 to 40 Hz. Furthermore, as shown in FIG. 20, when a fan heater is used, the obtained pressure waveform tends to show a large amplitude in frequency components of about 20 to 40 Hz and about 250 Hz. In addition, the peak which exists in 60-Hz vicinity in FIGS. 16-20 is the noise by a commercial power source.

  FIG. 15 will be referred to again. The spectrum data storage unit 48 stores spectrum data as shown in FIGS. And the 1st judgment part 43a judges gas leak and the use gas appliance 10 based on this spectrum data.

  FIG. 21 is a flowchart showing the operation of the first determination unit 43a according to the third embodiment. As shown in FIG. 21, first, the first determination unit 43a determines whether or not a trigger signal is input from the trigger signal generation unit 44 (S61). If it is determined that the trigger signal has not been input (S61: NO), this process is repeated until it is determined that the trigger signal has been input.

  On the other hand, when it is determined that the trigger signal is input (S61: YES), the first determination unit 43a shortens the sampling time and measures the pressure with the shortened sampling time (S62). After the pressure measurement, the first determination unit 43a performs a Fourier transform on the gas pressure waveform measured in step S62 (S63).

  Thereafter, the first determination unit 43a reads the spectrum data at the time of gas leakage stored in the spectrum data storage unit 48 (S64). And the 1st judgment part 43a calculates the similarity degree of the spectrum data obtained by the Fourier transform of step S63, and the spectrum data read in step S64 (S65). This similarity may be the above NCC, or may be calculated by another calculation method. Next, the first determination unit 43a determines whether or not the similarity calculated in step S43 is greater than or equal to a specific value (S66).

  When it is determined that the similarity calculated in step S65 is greater than or equal to a specific value (S66: YES), the first determination unit 43a determines that a gas leak has occurred (S67). Then, the process shown in FIG. 21 ends.

  By the way, when it is judged that the similarity calculated in step S65 is not more than a specific value (S66: NO), the 1st judgment part 43a reads the spectrum data for every gas appliance (S68), and each spectrum data is used. The similarity is calculated (S69). Then, the first determination unit 43a determines that the type of gas appliance 10 indicated by the spectrum data having the maximum similarity is used (S70). Then, the process shown in FIG. 14 ends.

  In the processing of steps S69 and S70 shown in FIG. 14, it is determined that the gas appliance 10 indicated by the highest spectrum data is used by obtaining the similarity to all the spectrum data stored for each gas appliance. However, the present invention is not limited to this, and the degree of similarity with the stored spectrum data for each gas appliance is sequentially obtained, and the gas appliance 10 indicated by the spectrum data is used when the similarity becomes equal to or higher than a predetermined value. After that, it may be determined that the calculation of the similarity is stopped. This is because by doing so, the number of similarities calculated can be reduced, leading to a reduction in power consumption.

  Furthermore, in this embodiment, the waveform obtained by the electrical signal from the pressure sensor 42 is Fourier transformed to determine the type of the gas appliance 10 and to determine the gas leakage. However, since there is a certain correlation between the pressure and the flow rate, the waveform obtained by the electrical signal from the flow rate sensor 41 is Fourier transformed to determine the type of the gas appliance 10 and to determine the gas leak. Good.

  Thus, according to the gas meter 40 and the determination method according to the third embodiment, the determination accuracy can be improved as in the first embodiment.

  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.

  In the present embodiment, the determination device is the gas meter 40, but the determination device is not limited thereto, and the determination device may be configured separately from the gas meter 40.

  Furthermore, in the first embodiment, the similarity transition is calculated by the expression (1). However, the present invention is not limited to this, and the similarity transition may be calculated by another method.

  In the first embodiment, the first determination unit 43a is similar when there is no continuous NCC data calculated by the first determination unit 43a among the continuous NCC data stored in the similarity transition storage unit 46. It may be determined that the gas appliance 10 indicated by the continuous NCC data stored in the degree transition storage unit 46 is insufficient.

  In this embodiment, the example in which the fuel gas is LP gas has been described. However, the present invention is not limited to this, and the present invention can also be applied to the case of city gas.

  Moreover, in this embodiment, based on the gas leak vibration waveform in the minute time within 1 second, the gas leak and the gas appliance 10 to be used are judged. In particular, in this embodiment, the time for measuring the pressure and the flow rate is sufficient within one second, but it may be measured for a time longer than one second in advance.

  In the present embodiment, the similarity transition storage unit 46 stores continuous NCC data for each gas appliance 10. Only one piece of this continuous NCC data may be stored for one gas appliance 10, or a plurality of pieces may be stored for one gas appliance 10. For example, in a water heater, the continuous NCC varies depending on the water temperature in the water heater. In this case, if there is only one continuous NCC data stored in the similarity transition storage unit 46, there is a possibility that the determination of the gas appliance 10 to be used is erroneous depending on the water temperature of the water heater. Therefore, it is desirable to store a plurality of continuous NCC data for such a gas appliance 10. This is because the gas appliance 10 to be used can be determined with higher accuracy.

  In the third embodiment, the first determination unit 43a calculates the similarity in the entire frequency range of the spectrum data. However, the present invention is not limited to this, and the similarity may be calculated only in a part of the frequency range. For example, since the water heater has a feature that a large amplitude can be obtained in the spectrum data even in a frequency range of 100 Hz or higher, the gas appliance 10 to be used is also specified by calculating the similarity of the spectral data in the frequency range of 100 Hz or higher. be able to. In this way, the calculation amount can be reduced by calculating the similarity only in a part of the frequency range.

DESCRIPTION OF SYMBOLS 1 ... Gas supply system 10 ... Gas appliance 20 ... Regulator 31 ... 1st piping 32 ... 2nd piping 40 ... Gas meter (determination apparatus)
41 ... Flow sensor 42 ... Pressure sensor 43 ... Determining unit 43a ... First determining unit (first determining means)
43b ... 2nd judgment part (2nd judgment means)
43c ... Selection part (selection means)
44 ... Trigger signal generation unit 45 ... Generation unit 46 ... Similarity transition storage unit 47 ... Waveform pattern storage unit 48 ... Spectrum data storage unit

Claims (8)

First determination means for determining at least one of a gas leak and a gas appliance to be used from a waveform obtained during a minute time from a change in at least one of a gas flow rate and a gas pressure;
Second determination means for determining a gas appliance to be used from a waveform pattern of a gas flow rate obtained in a time longer than the minute time;
Select one of a first state in which only the first determination unit functions, a second state in which only the second determination unit functions, and a third state in which both the first and second determination units function Selection means to
A judgment device comprising: 2. The determination device according to claim 1, wherein the selection unit selects the first state in an initial state and selects the second state or the third state when a predetermined condition is satisfied. The determination device according to claim 2, wherein the selection unit selects the first state when the predetermined condition is not satisfied and is not satisfied. The selection means selects the second state when a change in gas flow rate is less than a second specified value despite a change in gas pressure being equal to or greater than a first specified value. The determination device according to any one of claims 1 to 3. The said selection means selects the said 3rd state, when it is judged that the gas appliance whose gas flow volume or the amplitude of a gas pressure is more than predetermined value is used. The said 3rd state is characterized by the above-mentioned. The determination device according to any one of the above. The selection means determines that a gas appliance having an amplitude of a gas flow rate or gas pressure of a predetermined value or more is used by the first determination means, and the gas flow rate is stabilized after the determination of the use of the gas appliance. When the flow rate value that is decreased later exceeds zero, the third state is selected to cause the second determination means to function,
The said 2nd judgment means judges the gas appliance used based on the waveform pattern of the flow rate after the gas appliance with which the amplitude of gas flow rate or gas pressure is more than predetermined value is used. Determining device described in 1. The selection means determines that a gas appliance having an amplitude of a gas flow rate or gas pressure of a predetermined value or more is used by the first determination means, and the gas flow rate is stabilized after the determination of the use of the gas appliance. The determination apparatus according to claim 5, wherein when the flow rate value that is reduced later is zero, the first state is selected without selecting the third state. A first determination step of determining at least one of a gas leak and a gas appliance to be used from a waveform obtained during a minute time from a change in at least one of a gas flow rate and a gas pressure;
A second determination step of determining the gas appliance to be used by matching the waveform pattern of the flow rate from when the gas flow rate is changed and a memory pattern stored in advance for each gas appliance;
Selection to select one of a first state in which the first determination step is executed, a second state in which the second determination step is executed, and a third state in which both the first and second determination steps are executed Process,
The determination method characterized by having.