JP5713695B2 - Gas status judgment device, gas status judgment method, and trigger signal generator - Google Patents

Description

  The present invention relates to a gas status determination device, a gas status determination method, and a trigger signal generation device.

  Conventionally, a gas appliance determination system that determines a gas appliance in use has been proposed. In this gas appliance judgment system, the flow rate value of the gas flowing in the flow path is monitored for a long time, the flow rate value pattern which is the transition of the gas flow rate value is recognized, and the gas appliance is judged from the flow rate value pattern (for example, Patent Literatures 1 to 3).

  However, in the gas appliance determination system, the flow rate value of the gas flowing in the flow path must be monitored for a long time, and the gas appliance cannot be determined in a short time. For this reason, it is desirable to be able to determine the gas appliance used (hereinafter referred to as the used gas appliance) from the gas flow value in a short time. Some of them show almost the same flow rate value, which increases the possibility of making an error in the judgment of the gas appliance used.

  In view of this, there has been proposed a gas status determination device that determines a gas appliance to be used from a waveform in a short time. This gas condition determination device is based on the theory that vibrations peculiar to the gas appliances are generated in the measured values of pressure and flow rate in a very short time immediately after the start or end of use of the gas appliances. And this gas condition judgment device monitors a measured value in order to judge a gas appliance use start time and an end time, and generates a trigger signal when this measured value changes more than predetermined. When a trigger signal is generated, the gas status determination device acquires a waveform in a minute time (for example, a maximum of 2 seconds) after the trigger signal is generated by high-speed sampling, and determines a gas appliance from the acquired waveform characteristics in the minute time. Like to do. Moreover, in this gas appliance judgment apparatus, it is judged also about the gas leak from the characteristic of the waveform in minute time. Thereby, in this gas condition judgment device, use gas appliance and gas leak judgment can be judged by data acquisition in a minute time, and gas appliance judgment and gas leak judgment in a short time are enabled (for example, refer to patent documents 4).

JP 2003-148728 A JP 2008-107262 A JP 2008-107301 A JP 2008-108169 A

  Here, in the gas status determination device described in Patent Document 4, since it is necessary to obtain a waveform in a minute time after the measurement value change of the gas pressure or gas flow rate, the trigger signal is determined by accurately determining the measurement value change time point. Need to be generated. However, the gas status determination device described in Patent Document 4 has room for improvement in the accuracy of determination at the time of measurement value change. That is, if the trigger signal is generated when the measured value changes by a predetermined value or more, if there is vibration in the measured value of pressure or flow rate, the trigger signal is generated at that time. For this reason, there is a possibility that an erroneous trigger signal may be generated because it is not possible to accurately determine when the gas appliance starts to be used and when it ends and when the measured value changes when the gas leak occurs.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to improve the accuracy of judgment at the time of measurement value change and generate a trigger signal more accurately. It is an object of the present invention to provide a gas status determination device, a gas status determination method, and a trigger signal generation device that can be performed.

The gas status determination device of the present invention includes at least a pressure sensor that outputs a measurement value signal corresponding to the gas pressure in the flow path, and a flow rate sensor that outputs a measurement value signal corresponding to the gas flow rate in the flow path. Based on a waveform consisting of a measurement sensor consisting of one, a trigger signal generation means for generating a trigger signal, and a measurement value output by the measurement sensor during a minute time from the time when the trigger signal is generated by the trigger signal generation means, And a trigger signal generator for reading a measurement value signal from the measurement sensor every predetermined time, and the measurement value indicated by the read signal is greater than the predetermined time. If there is a large change than the predetermined value even for a long predetermined time before the measurement, and the temporary trigger signal generating means for generating a temporary trigger signal, the temporary trigger signal generating hand Optionally the temporary trigger signal is generated, the value changes with a change in the same direction when there significant change than the predetermined value specified time second predetermined value or more lower than a predetermined value than the previous measurement value, defined And a trigger signal generating means for generating the trigger signal as a trigger signal when the measured value from before time is continuously included a plurality of times.

Further, the gas status determination method of the present invention includes a trigger signal generation step for generating a trigger signal, and a measurement value corresponding to the gas pressure in the flow path during a very short time from the trigger signal generation time in the trigger signal generation step. Based on a waveform consisting of a measurement value output by a measurement sensor consisting of at least one of a pressure sensor that outputs a signal and a flow rate sensor that outputs a signal of a measurement value corresponding to the gas flow rate in the flow path, A determination step of determining at least one of the used gas appliances, and in the trigger signal generation step, a measurement value signal is read from the measurement sensor every predetermined time, and the measurement value indicated by the read signal is less than the predetermined time. If there is a large change than a predetermined value for a long predetermined time before the measurement, and the temporary trigger signal generating step of generating a temporary trigger signal, the temporary trigger signal generating step If Oite temporary trigger signal is generated, the value changes with a change in the same direction when there significant change than the predetermined value specified time second predetermined value or more lower than a predetermined value than the previous measurement value, A trigger signal generating step of generating the trigger signal as a trigger signal when the measured value from a predetermined time before is included a plurality of times continuously.

The trigger signal generation device of the present invention is a trigger signal generation device that generates a trigger signal, and reads a measurement value signal from a measurement sensor every predetermined time, and the measurement value indicated by the read signal is less than the predetermined time. A temporary trigger signal generating means for generating a temporary trigger signal and a temporary trigger signal generated by the temporary trigger signal generating means when there is a change larger than a predetermined value with respect to a measured value before a long specified time. A value that has changed more than a second predetermined value smaller than a predetermined value from a measured value before the specified time in the same direction as the change direction when there is a change larger than the value is continuously repeated several times among the measured values from the specified time before And a trigger signal generating means for generating the trigger signal as a trigger signal.

  According to these, the measurement value from the measurement sensor is read every predetermined time, and the temporary trigger signal is generated when the measurement value indicated by the read signal has a change larger than the predetermined value with respect to the measurement value before the specified time. Let For this reason, if the measured value indicated by the read signal changes more than the specified value relative to the measured value before the specified time, a temporary trigger signal is generated, and the measured value changes more than the specified value. Is not determined as the measurement value change time at the start or end of use of the gas appliance and the occurrence of gas leakage, and no trigger signal is generated.

  When a temporary trigger signal is generated, a value that has changed by more than the second predetermined value from the measured value before the specified time in the same direction as the change direction when there is a change greater than the predetermined value is measured from the specified time before. When the value is continuously included a plurality of times, this trigger signal is generated as a trigger signal. For this reason, after the provisional trigger signal is generated, the measurement values from before the specified time are referred to, and these measurement values are equal to or more than the second predetermined value in the same direction in a plurality of times with respect to the measurement values before the specified time. It will be judged that it is changing. Here, at the start of use of the gas appliance or when a gas leak occurs, the gas pressure tends to continuously decrease and the gas flow rate tends to increase continuously until the gas flow rate reaches a predetermined flow rate value. Similarly, at the end of use of the gas appliance, the gas pressure tends to continuously increase and the gas flow rate tends to decrease continuously until the gas flow rate decreases to a predetermined flow rate value. Therefore, by determining the continuity of the change of the second predetermined value or more in the same direction, it is possible to more accurately determine the start time and end time of use of the gas appliance, and the time of occurrence of gas leakage, and to use this trigger signal as a trigger signal. Can be generated as

  Therefore, it is possible to improve the accuracy of judgment at the time of measurement value change and generate a trigger signal more accurately.

  According to the gas status judgment device, gas status judgment method, and trigger signal generation device of the present invention, the accuracy of judgment at the time of measurement value change can be improved and a trigger signal can be generated more accurately.

It is a lineblock diagram of a gas appliance judgment system 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 figure which shows the outline of the gas leak vibration waveform produced | generated by CPU shown in FIG. It is a figure which shows the pressure change at the time of gas leak. It is a graph which shows continuous NCC at the time of gas leak. It is a graph which shows the pressure change at the time of gas appliance use start, Comprising: (a) shows the pressure change at the time of gas table use start, (b) shows the pressure change at the time of a small water heater use start, (c) Indicates the pressure change at the start of use of the water heater. It is a graph which shows the continuous NCC calculated by CPU shown in FIG. 2, (a) shows the continuous NCC at the time of a gas table use start, (b) shows the continuous NCC at the time of a small water heater use start. (C) has shown the continuous NCC at the time of a water heater start use. It is a graph which shows the spectrum data calculated by CPU shown in FIG. 2, Comprising: 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 calculated by CPU shown in FIG. 2, (a) shows the spectrum data at the time of starting use of a gas table, (b) shows the spectrum data at the time of starting use of a small water heater. (C) has shown the spectrum data at the time of a water heater start use. It is a timing chart which shows the mode of generation | occurrence | production of the temporary trigger signal by CPU shown in FIG. It is a timing chart which shows the mode of generation | occurrence | production of this trigger signal by CPU shown in FIG. It is a flowchart which shows the gas condition judgment method which concerns on this embodiment. It is a flowchart which shows the detail of the temporary trigger signal generation process (S1) shown in FIG. It is a flowchart which shows the detail of this trigger signal generation process (S3) shown in FIG. FIG. 13 is a flowchart showing details of the gas leakage / starting gas appliance determination process (S6) shown in FIG. 12 and shows a first determination method. FIG. 13 is a flowchart showing details of the gas leakage / starting gas appliance determination process (S6) shown in FIG. 12 and shows a second determination method. It is a graph which shows the pressure change at the time of completion | finish of gas appliance use, Comprising: (a) shows the pressure change at the time of completion | finish of use of a gas table, (b) shows the pressure change at the time of completion | finish of use of a small water heater, (c) Indicates the pressure change at the end of use of the water heater. It is a graph which shows the continuous NCC calculated by CPU shown in FIG. 2, Comprising: (a) shows continuous NCC at the time of completion | finish of use of a gas table, (b) is continuous at the time of completion | finish of use of a small water heater. NCC is shown, (c) has shown continuous NCC at the time of the end of use of a water heater. It is a graph which shows the spectrum data calculated by CPU shown in FIG. 2, Comprising: (a) shows the spectrum data at the time of completion | finish of use of a gas table, (b) shows the spectrum data at the time of completion | finish of use of a small water heater. , (C) shows the spectrum data at the end of use of the water heater. It is a flowchart which shows the gas condition judgment method which concerns on 2nd Embodiment. It is a flowchart which shows the detail of the completion | finish gas appliance determination process (S56) shown in FIG. 20, Comprising: The 1st determination method is shown. It is a flowchart which shows the detail of the completion | finish gas appliance determination process (S56) shown in FIG. 20, Comprising: The 2nd determination method is shown.

  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 appliance determination system including a gas appliance determination device according to an embodiment of the present invention. The gas appliance determination system 1 includes a plurality of gas appliances 10 such as a gas stove, a fan heater, a gas water heater, a floor heater, and a gas table, a gas supply source regulator 20, pipes 31 and 32, a gas meter (gas appliance). Determination device) 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 pressure sensor (measurement sensor) 41, an A / D converter 42, a CPU (trigger signal generation means, determination means) 43, and a memory 44. The A / D converter 42 and the memory 44 may be built in the CPU 43. The A / D converter 42 may be built in the pressure sensor 41. The pressure sensor 41 outputs a measurement value signal (analog signal) corresponding to the gas pressure in the flow path of the gas meter 40, and is configured by a sensor such as a piezoresistive type or a capacitance type.

  The pressure sensor 41 outputs a measurement value signal (analog signal) corresponding to the gas pressure in the flow path of the gas meter 40, and is configured by a sensor such as a piezoresistive type or a capacitance type. The A / D converter 42 receives the analog measurement value signal output from the pressure sensor 41, digitizes it, and outputs it to the CPU 43.

  One of the functions of the CPU 43 is to generate a trigger signal on the basis of the measurement value change time at the start of use of the gas appliance 10 and the gas leak occurrence time. The CPU 43 reads a digital measurement value signal transmitted from the pressure sensor 41 via the A / D converter 42 every predetermined time (for example, 2 ms). Further, the CPU 43 stores / accumulates the measured value data indicated by the digital signal in the memory 44 for a specified time (for example, 25 to 75 msec).

  Further, the CPU 43 includes a temporary trigger signal generation function (temporary trigger signal generation means), a main trigger signal generation function (main trigger signal generation means), and a gas leak / gas appliance determination function (determination means). The temporary trigger signal generation function compares the measured value indicated by the read signal with the measured value indicated by the signal before the specified time of the read signal, and the measured value indicated by the read signal is compared with the measured value before the specified time. This is a function for generating a temporary trigger signal when there is a change larger than a predetermined value. This temporary trigger signal is internally generated in the CPU 43.

  Further, when generating a temporary trigger signal, the CPU 43 validates this trigger signal generation function. The trigger signal generation function specifies the change direction of the pressure value when the temporary trigger signal is generated, that is, the change direction when the change is larger than a predetermined value. Here, in this embodiment, the change direction is a lower direction.

  Further, the trigger signal generation function refers to the accumulated measurement value from the specified time. At this time, the trigger signal generation function is configured such that a value that has changed by a second predetermined value or more in a specified change direction (a lower direction in the present embodiment) with respect to the measurement value before the specified time is It is determined whether or not the measurement value is continuously included a plurality of times. When it is determined that the trigger signal generation function is included, the trigger signal generation function generates the trigger signal as a trigger signal. This trigger signal is also generated internally in the CPU 43.

  The memory 44 stores information on the measurement value indicated by the signal from the pressure sensor 41. That is, the memory 44 stores and accumulates pressure data for a specified time. Further, when the trigger signal is generated, the CPU 43 collects a predetermined number (for example, continuous 200) of pressure data from the trigger signal generation time and stores it in the memory 44. Then, the gas leak / gas appliance determination function of the CPU 43 is activated, and the gas leak and the gas appliance 10 to be used are determined based on a predetermined number of pressure data.

  Further, when the gas leakage / gas appliance determination function of the CPU 43 is validated, the trigger signal generation function stops functioning.

  Next, the use gas appliance 10 by the CPU 43 and a method for determining gas leakage will be described. First, the present inventors have found that vibration occurs in the measured pressure value immediately after the start of use of the gas appliance 10 or immediately after the occurrence of gas leakage (for example, 2 s at the maximum). In the following determination method, the used gas appliance 10 and gas leakage are determined by analyzing this vibration. In the following, two determination methods are exemplified, but the determination methods are not limited to the following.

  First, the first determination method will be described. The first determination method uses similarity transition. Specifically, in this embodiment, the similarity transition is continuous NCC, and continuous NCC refers to continuous normal cross correlation (NCC).

  In determining the gas appliance 10 to be used and gas leakage in the first determination method, the CPU 43 first generates a predetermined waveform. Here, the generated waveform is, for example, a vibration waveform when a gas leak is predicted to be obtained when the gas leak occurs.

  FIG. 3 is a diagram showing an outline of a gas leakage vibration waveform generated by the CPU 43 shown in FIG. As shown in FIG. 3, the CPU 43 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.

Next, the CPU 43 calculates a similarity transition between the generated predetermined vibration waveform and a waveform formed from a predetermined number of pressure data. More specifically, the similarity _RNCC is obtained by the following equation (1). CPU43, by performing the calculation of the similarity _{R NCC} according to the equation (1) continuously, the similarity transition (i.e., that a continuous NCC) Request.

  After calculating the similarity transition, the CPU 43 determines that a gas leak has occurred when the representative value of the calculated similarity transition is equal to or greater than a threshold value. Here, the representative value may be the total degree of similarity or the average value for a specific period of the whole degree of similarity, or the degree of similarity at a specific time after the trigger signal is generated. Other values may be used.

  FIG. 4 is a diagram showing a pressure change at the time of gas leakage. As shown in FIG. 4, when a gas leak occurs, a waveform that vibrates while the pressure decreases is shown. This waveform has a high correlation with the gas leakage vibration waveform generated by the CPU 43 as shown in FIG. For this reason, the representative value of the similarity transition shows a high value, and the CPU 43 determines that a gas leak has occurred.

  FIG. 5 is a graph showing continuous NCC at the time of gas leakage. In FIG. 5, the solid line and the broken line indicate continuous NCCs when conditions such as a difference in piping state, a difference in gas leak location, and a difference in gas leak flow rate are different in each home.

  As shown in FIG. 5, 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 CPU 43 determines that a gas leak has occurred when the representative value of the calculated similarity transition is “0.9” or more.

  FIG. 6 is a graph showing the pressure change at the start of gas appliance use, where (a) shows the pressure change at the start of use of the gas table, and (b) shows the pressure change at the start of use of the small water heater. (C) has shown the pressure change at the time of a water heater start use.

  As shown in FIG. 6A, a pressure waveform that smoothly vibrates at a pressure of about 2.9 kPa is obtained at the start of use of the gas table. In addition, as shown in FIG. 6B, a pressure waveform is obtained in which the pressure vibrates strongly by 0.1 kPa with reference to 2.93 kPa at the end of use of the small water heater. Furthermore, as shown in FIG. 6 (c), a pressure waveform is obtained that shows a slightly rougher vibration than the small water heater on the basis of the pressure of 2.93 kPa at the end of use of the water heater.

  FIG. 7 is a graph showing the continuous NCC calculated by the CPU 43 shown in FIG. 2, wherein (a) shows the continuous NCC at the start of gas table use, and (b) at the start of use of the small water heater. The continuous NCC is shown, and (c) shows the continuous NCC at the start of use of the water heater.

  When the use of the gas table is started, the vibration waveform of FIG. 6A is obtained, and the continuous NCC calculated by the CPU 43 is as shown in FIG. That is, the continuous NCC initially shows about “1.0”, then falls below “0.2”, and returns to “0.95” in about 0.04 seconds. The continuous NCC becomes about “0.5” in about 0.1 second, and then slowly rises to near “0.65”.

  When the use of the small water heater is started, the vibration waveform of FIG. 6B is obtained, and the continuous NCC calculated by the CPU 43 is as shown in FIG. That is, the continuous NCC initially shows about “1.0”, then falls below “0.2”, and returns to “0.9” in about 0.04 seconds. Then, the continuous NCC again decreases to about “0.4”, and then slowly increases to near “0.7”.

  When the use of the water heater starts, the vibration waveform shown in FIG. 6C is obtained, and the continuous NCC calculated by the CPU 43 is as shown in FIG. That is, the continuous NCC initially shows a value of “0.8”, then falls below “0.2” and returns to “0.7” in about 0.02 seconds. Then, the continuous NCC decreases to about “0.6” and then returns to about “0.7”. After that, the continuous NCC again decreases to about “0.5”, and then becomes less than “0.6” in about 0.1 second. Thereafter, the continuous NCC rises slowly to near “0.65”.

  Thus, at the start of use of the gas appliance 10, the continuous NCC does not show “0.9” or more in most periods. For this reason, when the representative value of the continuous NCC is not equal to or greater than the threshold value, the determination unit 52a determines that the gas appliance 10 has been used, not a gas leak.

  The continuous NCC is different for each gas appliance 10. Therefore, the CPU 43 determines the gas appliance 10 to be used from such a continuous NCC pattern. Specifically, a continuous NCC pattern of each gas appliance 10 is stored in the memory 44. That is, the memory 44 stores a continuous NCC pattern as shown in FIG. 7 (a) for the gas table, and stores a continuous NCC pattern as shown in FIG. 7 (b) for the small water heater, A continuous NCC pattern as shown in FIG. 7C is stored for the water heater. Then, the CPU 43 determines that use of the gas appliance 10 indicated by the continuous NCC data closest to the calculated continuous NCC among the continuous NCC data stored in the memory 44 has started.

Next, a method for generating a predetermined vibration waveform generated by the CPU 43 will be described. The CPU 43 generates a gas leak vibration waveform as follows. First, the CPU 43 stores the following formula (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 41. Next, these calculation methods will be described with reference to FIG.

The CPU 43 calculates the frequency ω _{d of the} damped vibration from the following equation (3).

Here, Tp is an overshoot time, and as shown in FIG. 4, refers to the time from the occurrence of a pressure change to the first extreme value V1 (minimum value V1). CPU43, when the first extreme V1 is confirmed from the measured value data, 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 CPU 43 calculates the gain K from the following equation (4).

  Since it is such a formula, CPU43 will calculate gain K from a formula (4), if extreme values V1, M, and V2 are checked from measurement value data.

  As is clear from FIG. 4, 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 CPU 43 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. 4). Further, the CPU 43 may calculate the gain K by taking into account the fourth and subsequent extreme values from when the pressure change has occurred.

Next, the CPU 43 calculates an attenuation 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 an expression, when the extreme values V1 and M are confirmed from the measured value data, the CPU 43 calculates the attenuation ratio ζ from the expression (5).

As described above, the CPU 43 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 CPU43 will obtain | require continuous NCC according to Formula (1) from the calculated | required formula and measured value data (pressure waveform).

Here, the CPU 43 may calculate the frequency ω _{d of the} damping vibration and the damping ratio ζ as follows. That is, the vibration waveform shown in FIG. 4 tends to depend on the flow rate at the time of gas leakage. For this reason, the CPU 43 may store an expression including only the flow rate value as a variable in advance and substitute the flow rate value into this expression to obtain the damping vibration frequency ω _d and the damping ratio ζ.

Specifically, the CPU 43 obtains the damping vibration frequency ω _d and the damping ratio ζ from the following equation (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.

  Further, in this case, the CPU 43 desirably obtains the gain K from the difference between the pressure value before the pressure change occurrence and the pressure value after the pressure change occurrence without calculating the gain K from the equation (4). This is because the amount of calculation can be further reduced.

  Next, the second determination method will be described. The second determination method uses spectral data. Specifically, the CPU 43 according to the present embodiment calculates spectral data by Fourier transforming the vibration waveform. The CPU 43 is not limited to calculating spectrum data by Fourier transform, and may calculate spectrum data by other methods.

  FIG. 8 is a graph showing the spectrum data calculated by the CPU 43 shown in FIG. 2 and showing the spectrum data obtained by Fourier transforming the pressure waveform when a gas leak occurs. As shown in FIG. 8, when a gas leak occurs, the obtained pressure waveform contains almost no frequency component of 20 Hz or more. In addition, it is thought that the peak which exists in 60 Hz vicinity is the noise by a commercial power source.

  FIG. 9 is a graph showing spectrum data calculated by the CPU 43 shown in FIG. 2, wherein (a) shows spectrum data at the start of gas table use, and (b) at the start of use of the small water heater. The spectrum data is shown, and (c) shows the spectrum data at the start of use of the water heater.

  As shown in FIG. 9A, when the use of the gas table is started, the obtained pressure waveform has many frequency components of 30 Hz or less, and tends to show a large amplitude particularly in the vicinity of 10 to 20 Hz. Further, as shown in FIG. 9B, when the use of the small water heater is started, the pressure waveform includes a pressure component up to 150 Hz, and particularly tends to show a very large amplitude at about 30 Hz. Furthermore, as shown in FIG. 9C, when the use of the water heater is started, the pressure waveform includes a pressure component up to 180 Hz, and particularly tends to show a very large amplitude at about 20 Hz.

  Further, the memory 44 stores spectrum data as shown in FIGS. And CPU43 judges a gas leak and the use gas appliance 10 based on this spectrum data.

  That is, the CPU 43 compares the calculated spectrum data with the spectrum data stored in the memory 44, specifies the spectrum data having the highest similarity, and determines the occurrence of gas leakage and the gas appliance 10 to be used. Here, the similarity may be the above-described NCC, or may be a similarity calculated by another method.

  Next, trigger signal generation by the CPU 43 according to the present embodiment will be described in detail. As described above, the CPU 43 has a temporary trigger signal generation function and a main trigger signal generation function. With these functions, the CPU 43 collects pressure data by more accurately detecting when a gas leak occurs or when the gas appliance 10 starts to be used.

  FIG. 10 is a timing chart showing how the temporary trigger signal is generated by the CPU 43 shown in FIG. As described above, the CPU 43 reads the digitally converted signal from the pressure sensor 41 every predetermined time. Then, the CPU 43 compares the measured value at the time of reading with the measured value of the pressure before the specified time (corresponding to Nmsec shown in FIG. 10). Here, the measured value at the time of reading is a (I + n), and the measured value before the specified time is a (I) shown in FIG.

  The CPU 43 internally generates a temporary trigger signal when the pressure value indicated by the signal a (I + n) exceeds the predetermined value (TH1 (for example, 17 to 33 Pa) shown in FIG. 10) below the signal a (I). Let

  FIG. 11 is a timing chart showing how the trigger signal is generated by the CPU 43 shown in FIG. When generating the temporary trigger signal, the CPU 43 validates the trigger signal generation function, and indicates the change direction of the pressure value when the temporary trigger signal is generated, that is, the change direction when the change is larger than the predetermined value TH1. Identify. Here, the specified change direction is a lower direction.

  Next, the CPU 43 determines that the value that has changed in the specified change direction (the lower direction in the present embodiment) by a second predetermined value (TH2 shown in FIG. 11 (for example, 8 to 18 Pa, TH1> TH2)) or more is the specified time. It is determined whether or not the measured values from before are included continuously a plurality of times (for example, three times). Here, the measured value before the specified time is a measured value from a (I) to a (I + n) shown in FIG.

  Referring to FIG. 11, first, the measured value a (k-4) is equal to or less than the second predetermined value TH2. However, the measured value a (k−3) is not less than or equal to the second predetermined value TH2. For this reason, the CPU 43 does not determine that the value changed by the second predetermined value TH2 or more is continuously included in the measured value from the specified time before a plurality of times.

  Thereafter, the measured value a (k−2) is again equal to or smaller than the second predetermined value TH2. However, the measured value a (k−1) is not less than or equal to the second predetermined value TH2. For this reason, in this case as well, the CPU 43 does not determine that the value changed by the second predetermined value TH2 or more is continuously included in the measured value from the specified time before a plurality of times.

  Next, the measured value a (k) is again equal to or smaller than the second predetermined value TH2. Furthermore, the measurement value a (k + 1) and the measurement value a (k + 2) are continuously below the second predetermined value TH2. For this reason, the CPU 43 determines that the value changed by the second predetermined value TH2 or more is continuously included in the measured value from the specified time before a plurality of times. As a result, the CPU 43 generates this trigger signal as a trigger signal. At this time, the generation timing of the trigger signal is the time point of the measurement value a (k−1). As is apparent from FIG. 11, if the measurement value a (k), the measurement value a (k + 1), and the measurement value a (k + 2) change by the second predetermined value TH2 or more, the measurement value a (k), The magnitude relationship between the measured value a (k + 1) and the measured value a (k + 2) is not a problem.

  When the trigger signal is generated as described above, the CPU 43 accumulates and stores a predetermined number of pressure data from a (k−1), and the above-described determination process of the gas leak and the gas appliance 10 to be used based on the accumulated pressure data. Will be executed.

  Next, a gas status determination method according to the present embodiment will be described with reference to a flowchart. FIG. 12 is a flowchart illustrating a gas status determination method according to the present embodiment.

  First, the CPU 43 executes a temporary trigger signal generation process (S1). This process determines whether or not a temporary trigger signal is generated. Thereafter, the CPU 43 determines whether or not a temporary trigger signal has been generated in step S1 (S2).

  If it is determined that the temporary trigger signal has not been generated (S2: NO), the process proceeds to step S1. On the other hand, when it is determined that the temporary trigger signal has been generated (S2: YES), the CPU 43 executes the trigger signal generation process (S3). This process determines whether or not this trigger signal is generated. Thereafter, the CPU 43 determines whether or not the trigger signal is generated in step S3 (S4).

  When it is determined that the trigger signal is not generated (S4: NO), the process proceeds to step S1. On the other hand, when it is determined that the trigger signal is generated (S4: YES), the CPU 43 stores a predetermined number of pressure data in the memory 44 (S5). Thereafter, the CPU 43 executes a gas leak / start gas appliance determination process (S6). Next, the CPU 43 determines whether or not a gas leak has occurred in the process of step S6 (S7). If it is determined that a gas leak has occurred (S7: YES), the CPU 43 executes a security process (S8), and the process shown in FIG. 12 ends.

  On the other hand, if it is determined that no gas leak has occurred (S7: NO), the CPU 43 does not execute the security process, and the process shown in FIG. 12 ends.

  FIG. 13 is a flowchart showing details of the temporary trigger signal generation processing (S1) shown in FIG. As shown in FIG. 13, in the temporary trigger signal generation process, the CPU 43 first reads a digital signal transmitted from the pressure sensor 41 and converted by the A / D converter 42 (S11).

  Next, the CPU 43 determines whether or not the measurement value indicated by the digital signal read in step S11 has changed beyond a predetermined value TH1 with respect to the measurement value before the specified time (S12).

  If it is determined that the value has not changed beyond the predetermined value TH1 (S12: NO), the process shown in FIG. 13 ends, and the process proceeds to step S2 in FIG. On the other hand, if it is determined that the value has changed beyond the predetermined value TH1 (S12: YES), the CPU 43 generates a temporary trigger signal (S13). Then, the process illustrated in FIG. 13 ends, and the process proceeds to step S2 in FIG.

  FIG. 14 is a flowchart showing details of the trigger signal generation processing (S3) shown in FIG. As shown in FIG. 14, first, the CPU 43 specifies the changing direction when the pressure has changed more than a predetermined value TH1 (S21). Next, the CPU 43 determines whether or not a value that has changed more than the second predetermined value TH2 in the change direction specified in step S21 among the measured values from the specified time before is continuously included a plurality of times (for example, three times). Is determined (S22).

  When it is determined that it is not included continuously a plurality of times (S22: NO), the process shown in FIG. 14 ends, and the process proceeds to step S4 shown in FIG. On the other hand, when it is determined that it is continuously included a plurality of times (S22: YES), the CPU 43 generates this trigger signal (S23). At this time, the process shown in FIG. 14 ends, and the process proceeds to step S4 in FIG. In step S23, the trigger signal is generated at the time when the CPU 43 inputs the measurement value immediately before the measurement value that is consecutive multiple times. Further, the generation time of the trigger signal is not limited to this, and may be before a predetermined time, may be a time when there is a change exceeding the predetermined value TH1, or may be another time.

FIG. 15 is a flowchart showing details of the gas leakage / starting gas appliance determination process (S6) shown in FIG. 12, and shows a first determination method. As shown in FIG. 15, first, the CPU 43 determines the frequency ω _{d of the} damped vibration, the gain K, and the damping ratio ζ from the vibration waveform obtained during the minute time (S31). At this time, the CPU 43 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).

Next, the CPU 43 generates a gas leakage vibration waveform from the damping vibration frequency ω _d , the gain K, and the damping ratio ζ determined in step S31, based on a second-order delay step response equation (S32). At this time, the CPU 43 generates a gas leakage vibration waveform by substituting the damping vibration frequency ω _d , the gain K, and the damping ratio ζ determined in step S31 into the equation (2).

  And CPU43 calculates continuous NCC from Formula (1) based on the gas leak vibration waveform produced | generated in step S32, and the vibration waveform which consists of received pressure data (S33).

  Next, the CPU 43 determines a representative value of the continuous NCC and determines whether or not the representative value is equal to or greater than a threshold value (S34). When it is determined that the representative value is equal to or greater than the threshold value (S34: YES), the CPU 43 determines that a gas leak has occurred (S35). Thereafter, the process illustrated in FIG. 15 ends, and the process proceeds to step S7 illustrated in FIG.

  When it is determined that the representative value is not equal to or greater than the threshold value (S34: NO), the CPU 43 reads the stored similarity transition data for each gas appliance 10 (S36). Next, the CPU 43 specifies the closest NCC data calculated in step S33 among the continuous NCC data for each gas appliance 10 read in step S36, and determines the gas appliance 10 that has started to be used (S37). . Thereafter, the process illustrated in FIG. 15 ends, and the process proceeds to step S7 illustrated in FIG.

  In the process shown in FIG. 15, prior to determining the gas appliance 10 that has started to be used in step S <b> 37, priority is given to the determination of gas leakage requiring quickness by determining gas leakage in step S <b> 34. To improve safety.

  FIG. 16 is a flowchart showing details of the gas leakage / starting gas appliance determination process (S6) shown in FIG. 12, and shows a second determination method.

  As shown in FIG. 16, first, the CPU 43 calculates spectrum data from the vibration waveform obtained during a very short time (S41). After that, the CPU 43 reads out the gas leak spectrum data (S42), and calculates the similarity between the read out gas leak spectrum data and the spectrum data calculated in step S41 (S43).

  Next, the CPU 43 determines whether or not the similarity calculated in step S43 is greater than or equal to a specific value (S44). When it is determined that the similarity calculated in step S43 is greater than or equal to a specific value (S44: YES), the CPU 43 determines that a gas leak has occurred (S45). Then, the process illustrated in FIG. 16 ends, and the process proceeds to step S7 illustrated in FIG.

  By the way, when it is judged that the similarity calculated in step S43 is not more than a specific value (S44: NO), CPU43 reads the spectrum data for every gas appliance 10 (S46), and read the spectrum data for every gas appliance 10 And the similarity with the spectrum data calculated in step S41 is calculated (S47).

  Thereafter, the CPU 43 determines that the use of the type of gas appliance 10 indicated by the spectrum data having the maximum similarity is started (S48). Then, the process illustrated in FIG. 16 ends, and the process proceeds to step S7 illustrated in FIG.

  In the process shown in FIG. 16, prior to determining the gas appliance 10 that has started to be used in step S <b> 48, priority is given to the determination of gas leakage that requires quickness by determining gas leakage in step S <b> 44. To improve safety.

  As described above, according to the gas meter 40 and the gas status determination method according to the present embodiment, the measurement value from the pressure sensor 41 is read every predetermined time, and the measurement value indicated by the read signal becomes the measurement value before the specified time. On the other hand, when there is a change larger than the predetermined value TH1, a temporary trigger signal is generated. For this reason, when the measured value indicated by the read signal changes more than the predetermined value TH1 with respect to the measured value before the specified time, a temporary trigger signal is generated, and there is a change larger than the predetermined value TH1. In this case, it is not determined that the measured value changes at the start or end of use of the gas appliance, or when the gas leak occurs, and no trigger signal is generated.

  When a temporary trigger signal is generated, a value that has changed by more than the second predetermined value TH2 from the measured value before the specified time in the same direction as the change direction when there is a change greater than the predetermined value TH1 is This trigger signal is generated as a trigger signal when the measured value is continuously included a plurality of times. For this reason, after the provisional trigger signal is generated, the measurement values from before the specified time are referred to, and these measurement values are continuously transmitted in the same direction a plurality of times with respect to the measurement values before the specified time in the same direction. It is judged that the above has changed. Here, at the start of use of the gas appliance 10 or when a gas leak occurs, the gas pressure tends to continuously decrease until the gas flow rate reaches a predetermined flow rate value. Therefore, by determining the continuity of the change of the second predetermined value TH2 or more in the same direction, this trigger signal is generated as a trigger signal by more accurately determining the start of use of the gas appliance 10 or the occurrence of gas leakage. Can be made.

  Therefore, it is possible to improve the accuracy of judgment at the time of measurement value change and generate a trigger signal more accurately.

  Next, a second embodiment of the gas meter 40 and the gas status determination method according to the present embodiment will be described. The gas meter 40 according to the second embodiment is the same as that of the first embodiment, but the processing content is partially different. Hereinafter, differences from the first embodiment will be described.

  First, in the first embodiment, the CPU 43 was intended to accurately determine the start of use of the gas appliance 10 and the occurrence of gas leakage. However, in the second embodiment, the CPU 43 is used at the end of use of the gas appliance 10. The purpose is to accurately determine. Here, the present inventors have found that vibration occurs in the measured pressure value even in a minute time immediately after the use of the gas appliance 10 is finished (for example, 2 s at the maximum). In particular, this vibration shows a characteristic for each gas appliance 10 in the same manner as when the gas appliance 10 starts to be used. For this reason, in the second embodiment, various processing contents are different from those in the first embodiment due to the difference between when the use is started and when it is ended.

  Specifically, in the configuration illustrated in FIG. 2, the CPU 43 temporarily determines that the measured value indicated by the digital signal output from the A / D converter 42 exceeds the measured value before the specified time by exceeding a predetermined value TH1. Generate a trigger signal.

  Further, when the use of the gas appliance 10 is finished, the vibration waveform obtained is different from that at the start of use, and therefore continuous NCC and spectrum data are also different from the first embodiment.

  FIG. 17 is a graph showing the pressure change at the end of use of the gas appliance, where (a) shows the pressure change at the end of use of the gas table, and (b) shows the pressure change at the end of use of the small water heater. , (C) shows the pressure change at the end of use of the water heater.

  As shown in FIG. 17 (a), when the use of the gas table is finished, a pressure waveform that vibrates smoothly at a pressure of about 2.85 kPa is obtained. Further, as shown in FIG. 17B, a pressure waveform is obtained in which the pressure oscillates about 0.1 kPa based on 2.85 kPa at the end of use of the small water heater. Furthermore, as shown in FIG. 17 (c), a pressure waveform is obtained that shows a slightly rougher vibration than the gas table with the pressure at 2.88 kPa at the end of use of the water heater.

  18 is a graph showing the calculated continuous NCC calculated by the CPU 43 shown in FIG. 2, wherein (a) shows the continuous NCC at the end of use of the gas table, and (b) shows the use of a small water heater. The continuous NCC at the end time is shown, and (c) shows the continuous NCC at the end of use of the water heater.

  When the use of the gas table is finished, the vibration waveform of FIG. 17A is obtained, and the continuous NCC calculated by the similarity transition calculation unit 52c is as shown in FIG. That is, the continuous NCC initially shows about “0.9”, then falls below “0.2”, and returns to “0.8” in about 0.03 seconds. Then, the continuous NCC becomes about “0.6” in about 0.1 seconds, and thereafter maintains around “0.6”.

  When the use of the small water heater is finished, the vibration waveform of FIG. 17B is obtained, and the continuous NCC calculated by the similarity transition calculation unit 52c is as shown in FIG. 18B. That is, the continuous NCC initially shows about “0.9”, then falls below “0.2”, and returns to “0.8” in about 0.01 seconds. Then, the continuous NCC again decreases to about “0.3” and then returns to about “0.6”. Thereafter, the continuous NCC becomes about “0.6” in about 0.1 seconds while repeating small vibrations. Next, the continuous NCC slowly rises to near “0.7”.

  When the use of the water heater ends, the vibration waveform of FIG. 17C is obtained, and the continuous NCC calculated by the similarity transition calculation unit 52c is as shown in FIG. That is, the continuous NCC initially shows about “0.9”, then falls below “0.2”, and returns to “0.6” in about 0.02 seconds. The continuous NCC again decreases to about “0.45” and then returns to about “0.6”. Thereafter, the continuous NCC again decreases to about “0.45”, and then becomes “0.6” in about 0.1 second. Next, the continuous NCC slowly rises to near “0.7”.

  Thus, even when the use of the gas appliance 10 ends, the continuous NCC differs for each gas appliance 10, and the CPU 43 determines the gas appliance 10 whose use has ended from the pattern of such continuous NCC. Specifically, a continuous NCC pattern of each gas appliance 10 is stored in the memory 44. That is, the memory 44 stores the continuous NCC pattern as shown in FIG. 18A for the gas table, and stores the continuous NCC pattern as shown in FIG. 18B for the small water heater, A continuous NCC pattern as shown in FIG. 18C is stored for the water heater. And CPU43 judges that use of the gas appliance 10 which the continuous NCC data nearest to the calculated continuous NCC among the continuous NCC data memorize | stored in the memory 44 shows was complete | finished.

  FIG. 19 is a graph showing spectrum data calculated by the CPU 43 shown in FIG. 2, wherein (a) shows spectrum data at the end of use of the gas table, and (b) shows at the end of use of the small water heater. The spectrum data is shown, and (c) shows the spectrum data at the end of use of the water heater.

  As shown in FIG. 19A, when the use of the gas table is finished, the obtained pressure waveform has many frequency components of 30 Hz or less, and tends to show a large amplitude particularly in the vicinity of 10 to 20 Hz. Further, as shown in FIG. 19 (b), when the use of the small water heater is finished, the pressure waveform includes a pressure component up to 150 Hz, and tends to show a large amplitude particularly at about 90 Hz. Furthermore, as shown in FIG. 19 (c), when the use of the water heater is finished, it has a slightly large amplitude at about 30 Hz and tends to contain almost no other frequency components. The existing peak is considered to be noise due to commercial power.

  The memory 44 stores spectrum data as shown in FIG. Then, the CPU 43 determines the gas appliance 10 that has been used based on the spectrum data stored in the memory 44.

  That is, the CPU 43 compares the calculated spectrum data with the spectrum data stored in the memory 44, specifies the spectrum data having the highest similarity, and determines the gas appliance 10 that has been used. Here, the similarity may be the above-described NCC, or may be a similarity calculated by another method.

  FIG. 20 is a flowchart illustrating a gas status determination method according to the second embodiment. Note that the processing in steps S51 to S55 shown in FIG. 20 is the same as the processing in steps S1 to S5 shown in FIG.

  As shown in FIG. 20, in step S56, the CPU 43 executes end gas appliance determination processing (S56). By this processing, the gas appliance 10 that has been used is determined. Thereafter, the process shown in FIG. 20 ends.

  FIG. 21 is a flowchart showing details of the end gas appliance determination process (S56) shown in FIG. 20, and shows a first determination method. In steps S61 to S63 shown in FIG. 21, the same processing as steps S31 to S33 shown in FIG. 15 is executed.

  Thereafter, in steps S64 and S65 shown in FIG. 21, the same processes as in steps S36 and S37 shown in FIG. 15 are executed. Then, the process illustrated in FIG. 21 ends, and the process proceeds to step S57 illustrated in FIG.

  FIG. 22 is a flowchart showing details of the end gas appliance determination process (S56) shown in FIG. 20, and shows a second determination method. In step S71 shown in FIG. 22, the same processing as step S41 shown in FIG. 16 is executed.

  Thereafter, in steps S72 to S74 shown in FIG. 22, the same processes as in steps S46 to S48 shown in FIG. 16 are executed. Then, the process illustrated in FIG. 22 ends, and the process proceeds to step S57 illustrated in FIG.

  As described above, according to the gas meter 40 and the gas status determination method according to the second embodiment, as in the first embodiment, the accuracy of determination at the time of measurement value change is improved, and the trigger signal can be generated more accurately. Can be generated.

  Furthermore, according to the second embodiment, the end point of the gas appliance 10 can be determined more accurately.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment, You may add a change in the range which does not deviate from the meaning of this invention, and combines each embodiment. Also good.

  For example, in the above embodiment, the similarity transition is calculated by the equation (1). However, the present invention is not limited to this, and the similarity transition may be calculated by another method.

  Further, in the above embodiment, the CPU 43 determines that there is a shortage in the gas appliance 10 indicated by the stored continuous NCC data when there is no stored continuous NCC data that is similar to the calculated continuous NCC. Good.

  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.

  In the present embodiment, the gas leak and the gas appliance 10 to be used are determined based on the gas leak vibration waveform in a minute time of 2 seconds at the maximum. In particular, in this embodiment, the time for measuring the pressure is sufficient within 2 seconds (desirably within 1 second), but it may be preliminarily measured longer than 2 seconds.

  In the present embodiment, the memory 44 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 gas water heater, the continuous NCC varies depending on the water temperature in the gas water heater. In this case, if there is only one continuous NCC data stored in the memory 44, there is a possibility that the determination of the gas appliance 10 to be used is erroneous depending on the water temperature of the gas 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. Similarly, a plurality of spectrum data may be stored for one gas appliance 10.

  In the above embodiment, the CPU 43 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, at the end of use of the gas water heater, there is a feature that a large amplitude can be obtained in the spectrum data even in a frequency range of 100 Hz or higher. Therefore, it is also used by calculating the similarity of spectral data in the frequency range of 100 Hz or higher. The finished gas appliance 10 can be identified. In this way, the calculation amount can be reduced by calculating the similarity only in a part of the frequency range.

  Furthermore, in the said embodiment, it determines by calculating | requiring continuous NCC and calculating | requiring spectral data about the gas appliance 10 which use was complete | finished, the gas appliance 10 which use was started, and gas leakage. However, the present invention is not limited to this. For example, the waveform at a minute time as shown in FIG. 4, FIG. 6, or FIG. 17 is directly stored. The started gas appliance 10 and gas leakage may be determined. Furthermore, the gas appliance 10 that has been used, the gas appliance 10 that has started to be used, and the gas leakage may be determined from the direct characteristics of the waveform such as a specific point of the waveform.

  Furthermore, although the pressure sensor 41 is provided in the above embodiment, a flow rate sensor may be provided instead of or in addition to this. The flow sensor outputs a measurement value signal corresponding to the gas flow rate in the flow path of the gas meter 40, and includes an ultrasonic sensor, a flow sensor, or the like. Here, there is a certain correlation between the pressure and the flow rate. For this reason, based on the signal from the flow sensor, the use start time or end time of the gas appliance 10 and the occurrence of gas leakage may be determined. In this case, in the first embodiment, the CPU 43 generates a temporary trigger signal when the measured value indicated by the signal input via the A / D converter 42 is larger than the measured value before the specified time by a predetermined value. Will be generated. In the second embodiment, the above is reversed.

  Furthermore, in the said embodiment, it is also possible to use as a trigger signal generator which has a temporary trigger signal generation function and this trigger signal generation function. In this case, the trigger signal can be generated more accurately by externally attaching to the existing gas meter 40 or the like.

DESCRIPTION OF SYMBOLS 1 ... Gas appliance judgment system 10 ... Gas appliance 20 ... Regulator 31 ... 1st piping 32 ... 2nd piping 40 ... Gas meter (gas condition judgment apparatus)
41 ... Pressure sensor 42 ... A / D converter 43 ... CPU (trigger signal generation means, temporary trigger signal generation function, main trigger signal generation function, determination means)

Claims (5)

A measurement sensor comprising at least one of a pressure sensor that outputs a measurement value signal corresponding to the gas pressure in the flow path, and a flow rate sensor that outputs a measurement value signal corresponding to the gas flow rate in the flow path;
Trigger signal generating means for generating a trigger signal;
A determination means for determining at least one of gas leakage and a used gas appliance based on a waveform composed of a measurement value output by the measurement sensor in a minute time from a trigger signal generation time by the trigger signal generation means; With
The trigger signal generating means includes
When a measurement value signal is read from the measurement sensor every predetermined time, and the measurement value indicated by the read signal changes more than the predetermined value with respect to the measurement value before a predetermined time longer than the predetermined time , a temporary trigger Temporary trigger signal generating means for generating a signal;
When the temporary trigger signal is generated by the temporary trigger signal generating means, a second predetermined value smaller than the predetermined value than the measured value before the specified time in the same direction as the change direction when there is a change larger than the predetermined value. And a trigger signal generating means for generating the trigger signal as the trigger signal when a value changed more than a predetermined value is continuously included a plurality of times in the measured value from before the specified time. Gas status judging device. A memory for storing a measurement value indicated by a signal read from the measurement sensor every predetermined time for a specified time;
The temporary trigger signal generating means generates a temporary trigger signal when the measured value indicated by the read signal has a change larger than a predetermined value with respect to the measured value before the specified time stored in the memory,
The trigger signal generating means is configured to cause a value that has changed by more than the second predetermined value from the measured value before the specified time in the same direction to be measured a plurality of times among the measured values stored before the specified time stored in the memory. When included continuously, this trigger signal is generated as the trigger signal.
The gas status determination apparatus according to claim 1, wherein: The trigger signal generating means is configured to cause a value that has changed by more than the second predetermined value from the measured value before the specified time in the same direction to be measured a plurality of times among the measured values stored before the specified time stored in the memory. When included continuously, this trigger signal is generated as the trigger signal at the time of the previous measurement value that is consecutive multiple times.
The gas status determination apparatus according to claim 2, wherein A trigger signal generation step for generating a trigger signal;
A pressure sensor that outputs a signal of a measurement value corresponding to the gas pressure in the flow path within a minute time from the trigger signal generation time in the trigger signal generation step, and a measurement value corresponding to the gas flow rate in the flow path A determination step of determining at least one of a gas leak and a used gas appliance based on a waveform consisting of a measurement value output by a measurement sensor consisting of at least one of a flow rate sensor that outputs a signal,
In the trigger signal generation step,
When a measurement value signal is read from the measurement sensor every predetermined time, and the measurement value indicated by the read signal changes more than the predetermined value with respect to the measurement value before a predetermined time longer than the predetermined time , a temporary trigger A temporary trigger signal generating step for generating a signal;
When a temporary trigger signal is generated in the temporary trigger signal generation step, a second predetermined value smaller than the predetermined value than the measured value before the specified time in the same direction as the change direction when there is a change larger than the predetermined value. A trigger signal generating step of generating the trigger signal as the trigger signal when a value that has changed by more than a value is continuously included a plurality of times in the measured value from before the specified time. How to determine the gas status. A trigger signal generator for generating a trigger signal,
When a measurement value signal is read from the measurement sensor every predetermined time, and the measurement value indicated by the read signal changes more than the predetermined value with respect to the measurement value before a predetermined time longer than the predetermined time , a temporary trigger Temporary trigger signal generating means for generating a signal;
When the temporary trigger signal is generated by the temporary trigger signal generating means, a second predetermined value smaller than the predetermined value than the measured value before the specified time in the same direction as the change direction when there is a change larger than the predetermined value. A trigger signal generating means for generating a trigger signal as the trigger signal when a value changed more than a value is continuously included a plurality of times in the measured value from the specified time;
A trigger signal generation device comprising:

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