JP5468156B2 - Gas flow rate change judgment device - Google Patents

Description

  The present invention relates to a gas flow rate change determination device that detects a change in the flow rate of a gas flowing in a gas pipe connecting a gas supply source and a gas appliance.

  Conventionally, an electronic gas meter periodically measures the flow rate of a gas flowing through a gas pipe connecting a gas supply source and a gas appliance by a flow sensor, and can instantaneously measure the current flow rate of the gas. it can. According to such a gas meter, an accurate flow rate can be measured with respect to a gas flow having a stable flow rate. However, for example, when a gas appliance that is intermittently driven, such as a gas heat pump (GHP), is connected to the gas line, pressure fluctuations occur in the gas line, pulsation occurs, and the gas flow rate is reduced. Even in such a state, the gas meter instantaneously measures the flow rate, and the accuracy is lacking.

  On the other hand, in addition to the function of measuring the gas flow rate, the gas meter has a security function called a use time cutoff function (see, for example, Patent Document 1 and Patent Document 2). This usage time cutoff function measures the continuous usage time for the flow rate being used (that is, the flow rate segmented for each predetermined flow range), and this continuous usage time is determined by a predetermined time limit ( This function is to stop (shut off) the gas supply when the allowable use time is exceeded. Further, the allowable usage time is determined for each flow rate category, and when the flow rate category is switched to another flow rate category according to the flow rate change, the continuous usage time is reset and then measurement is started again.

  Since the gas meter described above has a problem in measurement accuracy in a situation where the gas flow rate is unstable, for example, when pulsation occurs, the flow rate is not changed so that the flow rate classification is originally switched. It is erroneously determined that there has been a change, and as a result, the flow rate classification is switched, the continuous use time is reset, and the continuous use time of the flow rate being used exceeds the allowable use time. There was a risk of danger.

  In order to solve such a problem, the instantaneous flow rate measurement is performed a predetermined number of times (average parameter number) in accordance with the current flow rate, and a value obtained by averaging the measured instantaneous flow rates (that is, a value) , An average value) is used to determine a flow rate change (see Patent Document 3). According to this technique, the average value of the instantaneous flow rate is obtained to improve the accuracy and the flow rate change error. In addition to preventing judgment, the number of flow measurement is changed according to the current flow rate.In particular, when the current flow rate is large, the average parameter is reduced to reduce the number of flow measurement times. The change in flow rate could be determined. In addition to the above, by increasing the flow rate change amount determination value used for determining the flow rate change and providing a sufficient margin, the same as the technique disclosed in Patent Document 3 described above. In addition to preventing such erroneous determination, the flow rate change can be determined in a short determination time by reducing the number of times of flow rate measurement (for example, once).

JP 2001-330493 A JP 2001-330244 A JP 2008-298587 A

  It is known that gas pulsation in a general gas supply facility occurs only in a limited manner, and pulsation hardly occurs in most gas usage environments. However, in the technique disclosed in Patent Document 3, the flow rate is measured the number of times (average parameter) determined based on the current flow rate regardless of whether or not pulsation occurs, so there is no pulsation. Even when the gas flow rate is in a stable state, the flow rate measurement may be performed many times, and there is a problem that the response to the flow rate change (that is, the judgment speed) becomes slow, and the average when the current flow rate is high Since the parameter is made small, if pulsation occurs in such a case, the determination accuracy of the flow rate change is lowered, and there is a possibility that erroneous determination may occur. In addition, in the configuration in which the flow rate change amount determination value used for the flow rate change determination is increased, the response to the flow rate change (that is, sensitivity) becomes dull and there is no pulsation, and the gas flow rate is in a stable state. Even if there is a change in the flow rate, if the flow rate change is detected and the continuous use time is reset, the flow rate change cannot be determined (that is, erroneous determination) and the continuous use time continues. As a result, the allowable usage time was exceeded and the gas supply was accidentally shut off.

  The present invention aims to solve the above problems. That is, an object of the present invention is to provide a gas flow rate change determination device capable of preventing an erroneous determination of a gas flow rate change and improving the response to the flow rate change when no pulsation occurs.

  In order to achieve the above object, the invention described in claim 1 is a flow rate acquisition means 31 for periodically acquiring the flow rate of the gas flowing in the gas pipeline, as shown in the basic configuration diagram of FIG. A change amount calculating means 32 for calculating a change amount between the two flow rates acquired successively by the flow rate acquiring means 31, and the change amount calculated by the change amount calculating means 32 and a preset change amount. In the gas flow rate change determining device 33, which has a flow rate change determining unit 33 for determining a change in the flow rate based on a comparison result with a determination value, the flow rate acquiring unit 31 is preset with an instantaneous flow rate of the gas. A pulsation detecting unit that measures the average number of times, calculates an average value of the plurality of instantaneous flow rates, obtains the average value as the flow rate, and detects whether or not the gas pulsation has occurred. 3 When the pulsation detecting means 34 detects that the pulsation has not occurred, the average parameter is changed to a speed-oriented parameter value, and the pulsation detecting means 34 detects that the pulsation has occurred. And an average parameter changing means 36 for changing the average parameter to an accuracy-oriented parameter value larger than the speed-oriented parameter value.

  According to the first aspect of the present invention, an average value of a plurality of instantaneous flow rates measured an average number of times is acquired as a flow rate used for determination of a change in flow rate, and the average parameter is set to determine whether or not there is gas pulsation. Based on the detection result, when it is detected that no pulsation has occurred, it is changed to a speed-oriented parameter value.When it is detected that pulsation has occurred, it is changed to an accuracy-oriented parameter value that is greater than the speed-oriented parameter value. Therefore, the average parameter can be changed to an appropriate value depending on whether or not pulsation occurs.

According to a second aspect of the present invention, in the first aspect of the present invention, as shown in the basic configuration diagram of FIG. 2, the pulsation detecting means 34 includes a plurality of pulsation detection periods that are continuous in time series. In each case, the pulsation detection period fluctuation amount measuring means 34a for measuring the fluctuation amount of the instantaneous flow rate generated in each pulsation detection period, and the pulsation detection period fluctuation amount measurement means 34a at each end of the pulsation detection period. Fluctuation amount pulsation detecting means 34b for detecting the presence or absence of occurrence of the pulsation during the pulsation detection period based on a comparison result between the fluctuation amount and the preset pulsation detection period fluctuation amount determination value. It is characterized by that.

According to the invention described in claim 2, after measuring the fluctuation amount of the instantaneous flow rate generated in each of a plurality of pulsation detection periods that are continuous in time series, the fluctuation is detected at each end of the pulsation detection period. Based on the comparison result between the amount and pulsation detection period fluctuation amount judgment value, the presence or absence of pulsation during the pulsation detection period is detected, so the presence or absence of pulsation is detected based on the amount of flow fluctuation during the pulsation detection period. it can.

According to a third aspect of the present invention, in the first aspect of the present invention, as shown in the basic configuration diagram of FIG. 3, the pulsation detecting means 34 includes a plurality of pulsation detection periods that are continuous in time series. In a plurality of divided periods each divided into a predetermined number of divisions, a divided period fluctuation amount measuring means 34c that measures the fluctuation amount of the instantaneous flow rate generated in each divided period, and the divided period at each end of the divided period Based on a comparison result between the fluctuation amount measured by the period fluctuation amount measuring unit 34c and a preset divided period fluctuation amount determination value, a flow rate for determining whether the flow rate state in the divided period is a stable state or an unstable state a state determination unit 34d, and the unstable state counting means 34e for counting the number of the flow conditions by the flow state determining means 34d is determined to be unstable the divided period, the instability counting Depending on the counting by stage 34e, the pulsation detecting period the unstable ratio calculating means flow conditions to calculate the ratio of the number of unstable state it determined to be the divided periods 34f for the division number of the unstable An unstable state ratio pulsation detecting unit 34g for detecting the presence or absence of the pulsation in the pulsation detection period based on a comparison result between the ratio calculated by the ratio calculating unit 34f and a ratio determination value set in advance. It is characterized by that.

According to the invention described in claim 3, the fluctuation amount of the instantaneous flow rate generated in each of the plurality of divided periods obtained by dividing each of the plurality of pulsation detection periods continuous in time series into a predetermined number of divisions was measured. After that, at each end of the divided period, it is determined whether the gas flow state in the divided period is a stable state or an unstable state based on the fluctuation amount, and the number of divided periods determined as the unstable state And calculating a ratio of the number of divided periods determined to be unstable with respect to the number of divisions of the pulsation detection period according to the count, and based on a comparison result between the ratio and the ratio determination value, Since the presence / absence of pulsation in the pulsation detection period is detected, the presence / absence of pulsation can be detected based on the ratio of the unstable state of the flow rate in the pulsation detection period.

  According to the first aspect of the present invention, the average parameter can be changed to an appropriate value depending on whether or not pulsation occurs, so when it is detected that no pulsation has occurred, the average parameter is It is possible to improve the judgment speed against the change in flow rate by changing to a smaller value-oriented parameter value, and when the occurrence of pulsation is detected, the average parameter is set to a value larger than the velocity-oriented parameter value. By changing to a precision-oriented parameter value, the accuracy of the flow rate can be improved, and an erroneous determination of a change in the flow rate due to the influence of pulsation can be prevented. Therefore, it is possible to prevent an erroneous determination of the gas flow rate change and improve the determination speed (reaction) for the flow rate change when no pulsation occurs.

According to the second aspect of the invention, since the presence or absence of occurrence of pulsation can be detected based on the fluctuation amount of the instantaneous flow rate in the pulsation detection period, for example, by setting the pulsation detection period to a relatively short time The change amount determination value and / or the average parameter can be quickly changed.

According to the third aspect of the present invention, since the presence or absence of pulsation can be detected based on the ratio of the unstable state of the flow rate state in the pulsation detection period, for example, the pulsation detection period is set to one day to several days, etc. By setting to a relatively long time, it is possible to avoid an unnecessary change amount determination value and / or average parameter change caused by a rare change in the pulsation occurrence state (that is, a change in the flow rate state).

It is a figure which shows the basic composition of the gas flow rate change determination apparatus of this invention. It is a figure which shows an example of the basic composition of the pulsation detection means of FIG. It is a figure which shows another example of the basic composition of the pulsation detection means of FIG. It is a principal part block diagram of the gas meter of the 1st Embodiment of this invention. It is a flowchart which shows an example of the judgment value change process which concerns on this invention in CPU of the gas meter of FIG. It is a flowchart which shows an example of the pulsation detection process which concerns on this invention in CPU of the gas meter of FIG. It is a flowchart which shows an example of the flow volume change determination process and usage time interruption | blocking process in CPU of the gas meter of FIG. It is a flowchart which shows another example of the determination value change process which concerns on this invention in CPU of the gas meter of FIG. It is a flowchart which shows another example of the pulsation detection process which concerns on this invention in CPU of the gas meter of FIG. 10 is a flowchart continued from FIG. 9.

(First embodiment)
Hereinafter, a gas meter as a first embodiment of a gas flow rate change determination device of the present invention will be described with reference to FIGS. This gas meter (indicated by reference numeral 1 in the figure) has the above-mentioned function of shutting down the use time as well as the function of measuring the flow rate of gas flowing through a gas pipe (not shown). Further, the gas meter 1 detects the presence or absence of pulsation from the amount of fluctuation in the flow rate in a pulsation detection period of a predetermined length that is continuous in time series, and changes the change amount determination value used to determine the change in gas flow rate. It has the function to do.

  FIG. 4 shows a block diagram of the main part of the gas meter 1. The gas meter 1 includes a microcomputer (hereinafter referred to as a microcomputer) 2, a flow rate detection unit 70, and a blocking unit 80. The microcomputer 2 includes a CPU 30 that performs various processes according to a predetermined processing program, a ROM 40 that stores a processing program in which the processes performed by the CPU 30 are described, various determination values, and a work area ( A RAM 50 having a data storage area for storing various data) and a timer 60 used for measuring the continuous use time of gas are provided, and these elements are connected by a bus line.

  The flow rate detection unit 70 includes a flow rate sensor such as a well-known ultrasonic sensor capable of measuring an instantaneous flow rate of gas flowing through a gas pipe (that is, a gas flow path) (not shown). The flow rate detector 70 measures the instantaneous flow rate of the gas periodically according to the measurement request signal from the microcomputer 2 or autonomously, and directs the flow rate signal corresponding to the measured instantaneous flow rate to the microcomputer 2. Output. Note that the ultrasonic sensor detects the instantaneous flow rate from the signal propagation time of the ultrasonic signal propagating in the gas flow path, as in the above-mentioned Patent Document 1 and Patent Document 2. The shut-off unit 80 includes a shut-off valve installed in the gas pipeline and a drive circuit for driving the shut-off valve. The drive circuit drives the shut-off valve in response to a control signal output from the microcomputer 2. Open and close the gas line to supply or shut off the gas.

  The CPU 30 executes a processing program stored in the ROM 40 to thereby obtain a flow rate acquisition means, a change amount calculation means, a flow rate change determination means, a pulsation detection means (a pulsation detection period fluctuation amount measurement means, a fluctuation amount pulsation detection means), and , Function as various means such as determination value changing means.

  The ROM 40 includes (1) a measurement frequency upper limit determination value used for determining the upper limit of the number of times of instantaneous flow rate measurement during the pulsation detection period, and (2) pulsation detection period variation used for determining the amount of fluctuation of the instantaneous flow rate during the pulsation detection period. An amount determination value, (3) a high sensitivity determination value as a change amount determination value used for determining a change in gas flow rate when it is detected that no pulsation has occurred in the pulsation detection period, and (4 ) Low sensitivity determination value (however, low sensitivity determination value> high sensitivity determination) as a change amount determination value used for determination of gas flow rate change when it is detected that pulsation has occurred in the pulsation detection period (Value), (5) various determination values and parameters such as allowable usage time (time limit) for each flow rate category are stored. In addition, each value is set so that the value obtained by multiplying the measurement period of the instantaneous flow rate in the flow rate detection unit 70 by the measurement number upper limit determination value becomes the length of the pulsation detection period. The ROM 40 stores in advance a precision-oriented parameter value and a speed-oriented parameter value. Further, for example, in the configuration in which the flow rate detection unit 70 measures the instantaneous flow rate Q at a cycle of 2 seconds, 32 is stored as a precision-oriented parameter value, 8 is stored as a speed-oriented parameter value, and the like.

  Further, the RAM 50 stores (1) an area for storing the number of times of measurement of the instantaneous flow rate in the pulsation detection period (flow rate measurement number C), and (2) the maximum value of the instantaneous flow rate in the pulsation detection period. Area (maximum value Qmax), (3) area (minimum value Qmin) where the minimum value of the instantaneous flow rate in the pulsation detection period is stored, and (4) determination value used for determination of gas flow rate change. A storage area for various data such as an area (change amount determination value X) to be performed (5) an area for storing a flow rate acquired immediately before (a previous flow rate Vpre) is provided. The RAM 50 is preliminarily provided with an average parameter storage area (average parameter Y).

  Hereinafter, an example of the pulsation detection process and the determination value change process according to the present invention executed by the CPU 30 will be described with reference to the flowcharts of FIGS. 5 and 6.

  When the power of the gas meter 1 is turned on, the CPU 30 of the microcomputer 2 provided in the gas meter 1 transmits a control signal for autonomous operation to the flow rate detection unit 70 and initializes a storage area for various data. After the initialization process, the process proceeds to step S100.

  In step S100, pulsation detection processing is performed. The pulsation detection process includes steps S110 to S200 as substeps.

  In step S110, the flow measurement count C is initialized (ie, C = 0). Also, the maximum value Qmax and the minimum value Qmin of the flow rate detected within the immediately preceding pulsation detection period are initialized. Then, the process proceeds to step S120.

  In step S120, the instantaneous flow rate Q is acquired based on the flow rate signal received from the flow rate detector 70. Then, the process proceeds to step S130.

  In step S130, the instantaneous flow rate Q acquired in step S120 is compared with the maximum value Qmax. When the instantaneous flow rate Q is larger than the maximum value Qmax, the process proceeds to step S140 (Y in S130), and the instantaneous flow rate Q is less than the maximum value Qmax. In step S150, the process proceeds to step S150 (N in S130).

  In step S140, the instantaneous flow rate Q is stored in the maximum value Qmax, and the maximum value Qmax is updated. Then, the process proceeds to step S170.

  In step S150, the instantaneous flow rate Q is compared with the minimum value Qmin. If the instantaneous flow rate Q is smaller than the minimum value Qmin, the process proceeds to step S160 (Y in S150), and if the instantaneous flow rate Q is greater than or equal to the minimum value Qmin, step S170 is performed. (N in S150).

  In step S160, the instantaneous flow rate Q is stored in the minimum value Qmin, and the minimum value Qmin is updated. Then, the process proceeds to step S170.

  In step S170, the flow rate measurement count C is incremented by one. Then, the process proceeds to step S180.

  In step S180, the flow rate measurement count C is compared with the measurement count upper limit determination value. If the flow rate measurement count C exceeds the measurement count upper limit determination value, it is assumed that the pulsation detection period has ended (elapsed). Proceeding to S190 (Y in S180), when the flow rate measurement count C is equal to or less than the measurement count upper limit determination value, it is assumed that the pulsation detection period has continued without ending, and the flow returns to step S120 (N in S180). The instantaneous flow rate Q is acquired again. That is, the pulsation detection period is measured based on the number of times of instantaneous flow rate Q that is periodically measured.

  In step S190, the fluctuation amount D of the instantaneous flow rate during the pulsation detection period is calculated by subtracting the minimum value Qmin from the maximum value Qmax. Then, the process proceeds to step S200.

  In step S200, the fluctuation amount D of the instantaneous flow rate calculated in step S190 is compared with the pulsation detection period fluctuation amount determination value. If the fluctuation amount D is equal to or greater than the pulsation detection period fluctuation amount determination value, the pulsation is detected in the pulsation detection period. When the fluctuation amount D is smaller than the pulsation detection period fluctuation amount determination value, it is assumed that no pulsation has been detected in the pulsation detection period. ) Ends.

  In step S310, it is determined whether or not pulsation has occurred in the pulsation detection process in step S100. If it is determined that pulsation has been detected, the process proceeds to step S320 (Y in S310), and the pulsation is detected. If it is determined that it has not been detected, the process proceeds to step S330 (N in S310).

  In step S320, the low sensitivity determination value is set (stored) in the change amount determination value X, and the accuracy-oriented parameter value is set in the storage area (average parameter Y) of the average parameter provided in advance in the RAM 50. Only the accuracy-oriented parameter value may be set without setting the low-sensitivity determination value (that is, the change amount determination value X is a constant value). And it returns to step S100 and performs again from the pulsation detection process mentioned above.

  In step S330, a determination value for high sensitivity is set (stored) in the change amount determination value X, and a speed-oriented parameter value (however, speed-oriented) is stored in an average parameter storage area (average parameter Y) provided in advance in the RAM 50. Set the population value <the accuracy-oriented population value). Only the speed-oriented parameter value may be set without setting the high sensitivity determination value (that is, the change amount determination value X is a constant value). And it returns to step S100 and performs again from the pulsation detection process mentioned above.

  Step S100 described above corresponds to the pulsation detecting means in the claims, steps S110 to S190 correspond to the pulsation detection period fluctuation amount measuring means in the claims, and step S200 corresponds to the fluctuation amount pulsation detecting means. Steps S310 to S330 correspond to determination value changing means in the claims.

  In the above-described flowchart, the pulsation detection period is measured based on the number of times the instantaneous flow rate Q is measured periodically (determination of the end of the pulsation detection period), but is not limited thereto. The timer 60 may be used to measure time. The pulsation detection process in step S100 detects the presence or absence of pulsation during the pulsation detection period. After the process is completed and the change amount determination value is set, the pulsation detection process is executed again. . That is, since the pulsation detection process is repeatedly executed, a plurality of pulsation detection periods are continued in time series.

  In addition, the CPU 30 executes a flow rate change determination process and a use time blocking process in parallel with the pulsation detection process and the determination value change process described above. An example of these flow rate change determination processing and usage time blocking processing will be described with reference to the flowchart of FIG.

  When the gas meter 1 is powered on, the CPU 30 of the microcomputer 2 included in the gas meter 1 performs a predetermined initialization process, and then proceeds to step S510 in parallel with the above-described pulsation detection process and determination value change process.

  In step S510, the timer T that counts the continuous usage time for the used flow rate (that is, the flow rate category) is initialized, and then the time measurement is started. Then, the process proceeds to step S520.

  In step S520, the flow rate V is acquired. As the flow rate V, the instantaneous flow rate Q is acquired a predetermined average parameter number (specifically, the average parameter value stored in the storage area (average parameter Y) of the average parameter value provided in advance in the RAM 50) times. Then, an average value of the plurality of instantaneous flow rates Q is calculated, and this average value is defined as a flow rate V. Thus, by using the average value of a plurality of instantaneous flow rates Q as the flow rate V, the influence of flow rate disturbance (pulsation) can be avoided and the accuracy can be improved. Then, the process proceeds to step S530.

  In step S525, the difference between the flow rate V acquired in step S520 and the previous flow rate Vpre is calculated, and the ratio of the difference to the flow rate V (that is, the flow rate change rate from the previous flow rate, hereinafter referred to as flow rate change amount H). ) Is calculated. Then, after the acquired flow rate V is stored in the immediately preceding flow rate Vpre, the process proceeds to step S530. In addition, as the change amount H of the flow rate, the difference between the flow rate V acquired in step S520 and a plurality of flow rates measured immediately before (the previous (preceding) flow rate, the previous two flow rates,...) An average value may be calculated and a ratio of the average value of the difference to the flow rate V may be calculated or used. Alternatively, the flow rate difference H may be used as the flow rate change amount H, which is suitable for the configuration of the gas meter. Things can be used.

  In step S530, the change amount H calculated in step S525 is compared with the change amount determination value X (that is, the high sensitivity determination value or the low sensitivity determination value). Then, when the change amount H is equal to or greater than the change amount determination value X, it is assumed that there is a change in the used flow rate (that is, there is a change in the flow rate category), and the process returns to step S510 (Y in S530) When the time is reset and the change amount H is smaller than the change amount determination value X, it is assumed that there is no change in the used flow rate (that is, there is no switching of the flow rate classification), and the timer T continues to count time, step S540. (N in S530).

  In step S540, the timer T is compared with a predetermined allowable usage time for the used flow rate, and if the timer T exceeds the allowable usage time, the process proceeds to step S550 (Y in S540), When the timer T is less than or equal to the allowable usage time, the process returns to step S520 (N in S540), and the flow rate V is acquired again.

  In step S550, a control signal for blocking the gas is transmitted to the blocking unit 80. Based on this control signal, the shut-off unit 80 drives the shut-off valve by the drive circuit to close the gas pipeline and shut off the gas. And the process of this flowchart is complete | finished.

  Step S520 described above corresponds to the flow rate acquisition means in the claims, step S525 corresponds to the change amount calculation means in the claims, and step S530 corresponds to the flow rate change determination means in the claims.

  Next, an example of the operation (action) of the above-described gas meter 1 in the pulsation detection processing and determination value change processing according to the present invention will be described.

  The pulsation detection period in the gas meter 1 is set to 48 seconds. The ROM 40 stores 5% as the high sensitivity determination value, 30% as the low sensitivity determination value, 3L / sec as the pulsation detection period fluctuation amount determination value, and 24 as the measurement frequency upper limit determination value of the instantaneous flow rate Q. ing. The flow rate detector 70 of the gas meter 1 measures the instantaneous flow rate Q at a cycle of 2 seconds.

  The gas meter 1 measures the instantaneous flow rate Q of the gas flowing through the gas pipeline (S120), acquires the maximum value and the minimum value of the instantaneous flow rate Q in the pulsation detection period (S130 to S160), and ends the period of the pulsation detection period. Every time (Y in S180), the fluctuation amount D of the instantaneous flow rate Q in the pulsation detection period is calculated from these maximum and minimum values (S190). When the fluctuation amount D is a value indicating that pulsation has occurred (D ≧ 3 L / second, Y in S200), the low sensitivity determination value is used as the change amount determination value X used for determining the flow rate change. When set (S320), and the fluctuation amount D is a value indicating that no pulsation has occurred (D <3L / sec, N in S200), a determination value for high sensitivity is set as the variation determination value X. (S330). Thus, in the current pulsation detection period, the flow rate V acquired using the change amount determination value selected by detecting the presence or absence of occurrence of pulsation based on the amount of fluctuation of the flow rate in the previous (immediately) pulsation detection period. The flow rate change is determined (S530).

  According to the present embodiment, when the CPU 30 detects that the change amount determination value X used for determining the flow rate change is based on the detection result of the presence or absence of gas pulsation, the sensitivity is high. When the occurrence of pulsation is detected, it is changed to a low sensitivity judgment value that is larger than the high sensitivity judgment value. Can be changed to any value.

  Further, after the CPU 30 measures (calculates) the flow amount fluctuation amount D generated in each of a plurality of pulsation detection periods that are continuous in time series, the fluctuation amount and the pulsation detection are detected every time the pulsation detection period ends. Since the presence / absence of pulsation during the pulsation detection period is detected based on the comparison result with the period variation determination value, the presence / absence of pulsation can be detected based on the amount of flow fluctuation during the pulsation detection period.

  As described above, according to the present invention, the change amount determination value X can be changed to an appropriate value depending on whether or not pulsation has occurred. Therefore, when it is detected that no pulsation has occurred, the change amount determination value X Can be changed to a small high-sensitivity determination value to increase the sensitivity to changes in flow rate, and when it is detected that pulsation has occurred, the change amount determination value X is changed to a high-sensitivity determination value. By changing the determination value to a larger value for low sensitivity, it is possible to prevent erroneous determination of a change in flow rate due to the influence of pulsation. Therefore, it is possible to prevent misjudgment of the gas flow rate change and to improve the sensitivity (reaction) to the flow rate change when no pulsation occurs.

  Further, since it is possible to detect the occurrence of pulsation based on the flow rate fluctuation amount D in the pulsation detection period, for example, by setting the pulsation detection period to a relatively short time, the change amount determination value can be quickly changed. .

  Further, the CPU 30 obtains an average value of a plurality of instantaneous flow rates Q measured average number of times as a flow rate V used for determination of flow rate change, and the average parameter is based on the detection result of the presence or absence of gas pulsation, When it is detected that no pulsation has occurred, it is changed to a speed-oriented parameter value.When it is detected that pulsation has occurred, it is changed to an accuracy-oriented parameter value that is greater than the speed-oriented parameter value. The average parameter can be changed to an appropriate value depending on whether or not it occurs. As is clear from the above operation, the CPU 30 also functions as an average parameter changing unit.

  If the average parameter can be changed to an appropriate value depending on whether pulsation has occurred or not, when it is detected that no pulsation has occurred, the average parameter is changed to a smaller value-oriented parameter value. Therefore, when it is detected that pulsation has occurred, the average parameter is changed to an accuracy-oriented parameter value that is greater than the speed-oriented parameter value. To prevent erroneous determination of changes in flow rate due to the influence of pulsation. Therefore, it is possible to prevent an erroneous determination of the gas flow rate change and improve the determination speed (reaction) for the flow rate change when no pulsation occurs.

(Second Embodiment)
Hereinafter, a gas meter as a second embodiment of the gas flow rate change determination device of the present invention will be described with reference to FIGS. 4 and 8 to 10. This gas meter (indicated by reference numeral 1A in the figure) has the function of measuring the flow rate of gas flowing through a gas pipe (not shown) as well as the function of shutting down the use time described above, as with the gas meter 1 of the first embodiment described above. . In addition, the gas meter 1A detects the presence or absence of pulsation from the ratio at which the gas flow rate becomes unstable during a time-series continuous pulsation detection period, and determines a change amount determination value used for determining a change in gas flow rate. Has the function to change.

  FIG. 4 shows a principal block diagram of the gas meter 1A. 1 A of gas meters are provided with the microcomputer (microcomputer) 2, the flow volume detection part 70, and the interruption | blocking part 80 similarly to the gas meter 1 of 1st Embodiment mentioned above. The microcomputer 2 includes a CPU 30 that performs various processes according to a predetermined processing program, a ROM 40 that stores a processing program in which the processes performed by the CPU 30 are described, various determination values, and a work area ( A RAM 50 having a data storage area for storing various data) and a timer 60 used for measuring the continuous use time of gas are provided, and these elements are connected by a bus line. Since the flow rate detection unit 70 and the blocking unit 80 are the same as those in the first embodiment described above, description thereof is omitted.

  The CPU 30 executes a processing program stored in the ROM 40 to thereby obtain a flow rate acquisition means, a change amount calculation means, a flow rate change determination means, a pulsation detection means (a divided period fluctuation amount measurement means, a flow rate state determination means, an unstable state count). Functions as a means, an unstable state ratio calculating means, an unstable state ratio pulsation detecting means), and a judgment value changing means.

  The ROM 40 includes (1) a measurement frequency upper limit determination value used for determination of the upper limit of the number of measurement of instantaneous flow rate in the divided period, and (2) divided period fluctuation amount determination value used for determination of the fluctuation amount of the instantaneous flow rate in the divided period. (3) the number of divisions in the pulsation detection period, (4) the ratio determination value used for determining the ratio of the number of division periods determined to be unstable with respect to the number of divisions in the pulsation detection period, and (5) in the pulsation detection period When it is detected that no pulsation has occurred, a highly sensitive determination value as a change amount determination value used for determining a gas flow rate change, and (6) that pulsation has occurred in the pulsation detection period. Low-sensitivity determination value (however, low-sensitivity determination value> high-sensitivity determination value) as a change amount determination value used for determination of gas flow rate change when detected, (7) Permissible for each flow rate category Usage time (when limited) ), Various determination values and parameters, such are stored. In the present embodiment, the value obtained by multiplying the instantaneous flow rate measurement period in the flow rate detection unit 70 by the above-described upper limit determination of the number of times of measurement is the length of the divided period, and the value obtained by multiplying this divided period by the number of divided parts is as follows. Each value is set so as to be the length of the pulsation detection period.

  In addition, the RAM 50 stores (1) an area for storing the number of times of measurement of the instantaneous flow rate in the divided period (flow rate measurement number C), and (2) the maximum value of the instantaneous flow rate in the divided period. Area (maximum value Qmax), (3) area in which the minimum value of the instantaneous flow rate in the divided period is stored (minimum value Qmin), and (4) area in which the determination value used to determine the change in gas flow rate is stored. (Change amount determination value X), (5) area for storing the flow rate acquired immediately before (flow rate Vpre immediately before), (6) area for storing the number of divided periods in which the flow rate is determined to be unstable (unstable) An information storage area such as the number of divided periods F) is provided.

  Hereinafter, another example of the pulsation detection process and the determination value change process according to the present invention executed by the CPU 30 will be described with reference to the flowcharts of FIGS.

  When the gas meter 1A is turned on, the CPU 30 of the microcomputer 2 included in the gas meter 1A transmits predetermined control signals such as transmission of control signals for autonomous operation to the flow rate detector 70 and initialization of storage areas for various data. After the initialization process, the process proceeds to step T100.

  In step T100, pulsation detection processing is performed. The pulsation detection process includes steps T105 to T240 as substeps.

  In step T105, the number of unstable division periods F is initialized (that is, F = 0), and a one-day timer that counts one day (24 hours) as a pulsation detection period is initialized to start timing. Then, the process proceeds to Step T110.

  In step T110, the flow rate measurement count C is initialized (ie, C = 0). Further, the maximum value Qmax and the minimum value Qmin of the flow rate detected in the immediately preceding divided period are initialized. Then, the process proceeds to Step T120.

  In step T120, the instantaneous flow rate Q is acquired based on the flow rate signal received from the flow rate detector 70. Then, the process proceeds to Step T130.

  In step T130, the instantaneous flow rate Q acquired in step T120 is compared with the maximum value Qmax. When the instantaneous flow rate Q is larger than the maximum value Qmax, the process proceeds to step T140 (Y in T130), and the instantaneous flow rate Q is less than the maximum value Qmax. In step S150, the process proceeds to step T150 (N in T130).

  In step T140, the instantaneous flow rate Q is stored in the maximum value Qmax, and the maximum value Qmax is updated. Then, the process proceeds to Step T170.

  In step T150, the instantaneous flow rate Q is compared with the minimum value Qmin. When the instantaneous flow rate Q is smaller than the minimum value Qmin, the process proceeds to step T160 (Y in T150), and when the instantaneous flow rate Q is greater than or equal to the minimum value Qmin, step T170 is performed. (N at T150).

  In step T160, the instantaneous flow rate Q is stored in the minimum value Qmin, and the minimum value Qmin is updated. Then, the process proceeds to Step T170.

  In step T170, the flow rate measurement count C is incremented by one. Then, the process proceeds to Step T180.

  In step T180, the flow rate measurement count C is compared with the measurement count upper limit determination value. If the flow rate measurement count C exceeds the measurement count upper limit determination value, it is determined that the divided period has ended (elapsed), and step T190 (Y in T180), when the flow rate measurement count C is equal to or less than the measurement count upper limit determination value, it is assumed that the division period continues without ending, and the process returns to step T120 (N in T180), and again. The instantaneous flow rate Q is acquired. In other words, the divided period is measured based on the number of times of instantaneous flow rate Q measured periodically.

  In step T190, the fluctuation amount D of the instantaneous flow rate in the divided period is calculated by subtracting the minimum value Qmin from the maximum value Qmax. Then, the process proceeds to Step T200.

  In Step T200, the fluctuation amount D of the instantaneous flow rate calculated in Step T190 is compared with the divided period fluctuation amount determination value. When the fluctuation amount D is equal to or larger than the divided period fluctuation amount determination value, the flow rate state in the divided period is not correct. It is determined that the state is stable, and the process proceeds to step T210 (Y in T200). When the fluctuation amount D is smaller than the divided period fluctuation amount determination value, it is determined that the flow rate state in the divided period is stable. The process proceeds to step T220 (N in T200).

  In Step T210, the unstable division period number F is increased by one. Then, the process proceeds to Step T220.

  In step T220, the ratio R of the unstable division period to the division number is calculated by dividing the unstable division period number F by the division number of the pulsation detection period. Then, the process proceeds to Step T230.

  In step T230, the ratio R calculated in step T220 is compared with the ratio determination value. When the ratio R is equal to or greater than the ratio determination value, it is determined that pulsation has occurred in the pulsation detection period, and the pulsation detection process is performed. When (T100) ends (Y in T230) and the ratio R is smaller than the ratio determination value, the process proceeds to Step T240 (N in T230).

  In step T240, it is determined whether the time counted by the one-day timer has passed one day. When one day has passed, it is determined that no pulsation has occurred in the pulsation detection period, and a pulsation detection process ( (T100) is ended (Y in T240), and if one day has not elapsed, the process returns to step T110 and the above-described processing is executed again.

  In step T310, it is determined whether or not pulsation has occurred in the pulsation detection process in step T100. If it is determined that pulsation has been detected, the process proceeds to step T320 (Y in T310), and the pulsation is detected. When it is determined that it has not been detected, the process proceeds to step T330 (N in T310).

  In step T320, a low sensitivity determination value is set (stored) in the change amount determination value X, and a precision-oriented parameter value is set in a storage area (average parameter Y) of an average parameter provided in advance in the RAM 50. Only the accuracy-oriented parameter value may be set without setting the low-sensitivity determination value (that is, the change amount determination value X is a constant value). Then, the process proceeds to Step T340.

  In step T330, a determination value for high sensitivity is set (stored) in the change amount determination value X, and a speed-oriented parameter value (however, speed-oriented) is stored in an average parameter storage area (average parameter Y) provided in advance in the RAM 50. Set the population value <the accuracy-oriented population value). Only the speed-oriented parameter value may be set without setting the high sensitivity determination value (that is, the change amount determination value X is a constant value). Then, the process returns to Step T100 and is executed again from the pulsation detection process described above.

  In step T340, it is determined whether the time counted by the one-day timer has passed one day, and the determination is repeated until one day has passed (N in T340). When one day has passed, the process returns to step T100 and described above. Execute again from the pulsation detection process.

  Step T100 described above corresponds to the pulsation detecting means in the claims, steps T110 to S190 correspond to the divided period variation measuring means in the claims, and step T200 corresponds to the flow rate state determining means in the claims. Correspondingly, step T210 corresponds to the unstable state counting means in the claims, step T220 corresponds to the unstable state ratio calculating means, and steps T230 and T240 correspond to the unstable state ratio pulsation detection in the claims. Steps T310 to T330 correspond to determination value changing means in the claims.

  In the above-described flowchart, the pulsation detection period is measured based on the number of times the instantaneous flow rate Q is measured periodically (determination of the end of the pulsation detection period), but is not limited thereto. The timer 60 may be used to measure time. Further, the pulsation detection process in step T100 detects the presence or absence of pulsation during the pulsation detection period. After the process is completed and the change amount determination value is set, the pulsation detection process is executed again. . That is, since the pulsation detection process is repeatedly executed, a plurality of pulsation detection periods are continued in time series.

  In addition, the CPU 30 executes a flow rate change determination process and a use time blocking process in parallel with the pulsation detection process and the determination value change process described above. Since these flow rate change determination processing and usage time blocking processing are the same as those in the first embodiment, description thereof will be omitted.

  Next, an example of the operation (action) of the gas meter 1A described above in the pulsation detection process and the determination value change process according to the present invention will be described below.

  The pulsation detection period in the gas meter 1A is set to one day. The ROM 40 has a high sensitivity determination value of 5%, a low sensitivity determination value of 30%, a divided period fluctuation amount determination value of 3 L / sec, a pulsation detection period division number of 96, and an instantaneous flow rate Q measurement number upper limit determination. 450 is stored as the value, and 25% is stored as the ratio determination value. The flow rate detector 70 of the gas meter 1 measures the instantaneous flow rate Q at a cycle of 2 seconds. That is, the length of the divided period is set to 15 minutes (15 minutes = 2 seconds × 450 = 24 hours / 96).

  The gas meter 1A measures the instantaneous flow rate Q of the gas flowing through the gas pipeline (T120), and acquires the maximum value and the minimum value of the instantaneous flow rate Q in a plurality of divided periods obtained by dividing the pulsation detection period into a predetermined number of divisions. (T130 to T160) At every end of the divided period (Y in T180), the fluctuation amount D of the instantaneous flow rate Q in the divided period is calculated from the maximum value and the minimum value (T190). When the fluctuation amount D is a value indicating that the flow rate is unstable (D ≧ 3 L / second, Y in S200), the divided period is counted as a divided period in which the flow rate is unstable. (T210). Then, the ratio R of the divided period in which the flow rate with respect to the pulsation detection period is in an unstable state is calculated (T220).

  When the ratio R is a value indicating that pulsation has occurred (R ≧ 25%, Y at T230), a low sensitivity determination value is set as the change amount determination value X used for determining the flow rate change (T320). After that, it waits for the remaining time of the pulsation detection period to elapse (T340). Alternatively, when the ratio R is a value indicating that no pulsation has occurred (R <25%, N at T230) and when the pulsation detection period has elapsed (Y at T240), the change amount determination value X A determination value for high sensitivity is set in (T330). Then, using the change amount determination value selected according to the ratio of the unstable state, the flow rate change of the acquired flow rate V is determined (T530).

  That is, when the ratio of the unstable state of the flow rate increases in the pulsation detection period, the determination value for low sensitivity is immediately switched to the determination value for low sensitivity, and in the current pulsation detection period and the subsequent pulsation detection period. When the flow rate change determination is performed or when it is confirmed that the ratio of the unstable state of the pulsation has decreased at the time when the current pulsation detection period has elapsed, it is switched to the determination value for high sensitivity and continued. In the pulsation detection period, the flow rate change determination using the high sensitivity determination value is performed.

  According to the present embodiment, when the change amount determination value X used for determining the flow rate change is detected based on the detection result of the presence or absence of gas pulsation, the determination value for high sensitivity is detected. When the occurrence of pulsation is detected, it is changed to a determination value for low sensitivity that is larger than the determination value for high sensitivity, so the change amount determination value is set to an appropriate value depending on whether pulsation has occurred. Can change.

  In addition, after measuring a flow amount variation D generated in each of a plurality of divided periods obtained by dividing each of a plurality of pulsation detection periods continuous in time series into a predetermined number of divisions, each time the period of the divided period ends , Determining whether the gas flow rate in the divided period is stable or unstable based on the fluctuation amount D, counting the number of divided periods determined to be unstable, and according to the count, A ratio R of the number of divided periods determined to be in an unstable state with respect to the number of divisions of the pulsation detection period is calculated, and the presence or absence of pulsation in the pulsation detection period is determined based on a comparison result between the ratio R and the ratio determination value. Since it detects, the presence or absence of a pulsation can be detected based on the ratio of the unstable state of the flow rate in the pulsation detection period.

  As described above, according to the present invention, the change amount determination value X can be changed to an appropriate value depending on whether or not pulsation has occurred. Therefore, when it is detected that no pulsation has occurred, the change amount determination value X Can be changed to a small high-sensitivity determination value to increase the sensitivity to changes in flow rate, and when it is detected that pulsation has occurred, the change amount determination value X is changed to a high-sensitivity determination value. By changing the determination value to a larger value for low sensitivity, it is possible to prevent erroneous determination of a change in flow rate due to the influence of pulsation. Therefore, it is possible to prevent misjudgment of the gas flow rate change and to improve the sensitivity (reaction) to the flow rate change when no pulsation occurs.

  In addition, since the presence or absence of pulsation can be detected based on the ratio of the unstable flow rate during the pulsation detection period, for example, by setting the pulsation detection period to a relatively long time such as one day to several days, It is possible to avoid an unnecessary change in the change amount determination value X caused by a change in the pulsation occurrence state (that is, a change in the flow rate state) that occurs only in

  Further, the CPU 30 obtains an average value of a plurality of instantaneous flow rates Q measured average number of times as a flow rate V used for determination of flow rate change, and the average parameter is based on the detection result of the presence or absence of gas pulsation, When it is detected that no pulsation has occurred, it is changed to a speed-oriented parameter value.When it is detected that pulsation has occurred, it is changed to an accuracy-oriented parameter value that is greater than the speed-oriented parameter value. The average parameter can be changed to an appropriate value depending on whether or not it occurs. As is clear from the above operation, the CPU 30 also functions as an average parameter changing unit.

  If the average parameter can be changed to an appropriate value depending on whether pulsation has occurred or not, when it is detected that no pulsation has occurred, the average parameter is changed to a smaller value-oriented parameter value. Therefore, when it is detected that pulsation has occurred, the average parameter is changed to an accuracy-oriented parameter value that is greater than the speed-oriented parameter value. To prevent erroneous determination of changes in flow rate due to the influence of pulsation. Therefore, it is possible to prevent an erroneous determination of the gas flow rate change and improve the determination speed (reaction) for the flow rate change when no pulsation occurs.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

1, 1A gas meter (gas flow rate change judgment device)
2 Microcomputer 30 CPU (flow rate acquisition means, change amount calculation means, flow rate change determination means, pulsation detection means, determination value change means, average parameter change means, pulsation detection period fluctuation amount measurement means, fluctuation amount pulsation detection means, division (Period fluctuation amount measuring means, flow rate state determining means, unstable state counting means, unstable state ratio calculating means, unstable state ratio pulsation detecting means)
40 ROM
50 RAM
60 Timer 70 Flow rate detection unit 80 Blocking unit

Claims (3)

A flow rate acquisition means for periodically acquiring the flow rate of the gas flowing in the gas pipeline, a change amount calculation means for calculating a change amount between the two flow rates acquired successively by the flow rate acquisition means, and the change In a gas flow rate change determination device comprising: a flow rate change determination unit that determines a change in the flow rate based on a comparison result between the change amount calculated by the amount calculation unit and a preset change amount determination value.
The flow rate acquisition means is provided as means for measuring the instantaneous flow rate of the gas by a predetermined average parameter number, calculating an average value of the plurality of instantaneous flow rates, and acquiring the average value as the flow rate, And
Pulsation detecting means for detecting presence or absence of occurrence of pulsation of the gas;
When the pulsation detecting means detects that the pulsation has not occurred, the average parameter is changed to a speed-oriented parameter value, and when the pulsation detecting means detects that the pulsation has occurred, An apparatus for determining a change in gas flow rate, comprising: an average parameter changing means for changing an average parameter to an accuracy-oriented parameter value larger than the speed-oriented parameter value. The pulsation detecting means is
In each of a plurality of pulsation detection periods continuous in time series, a pulsation detection period fluctuation amount measuring means for measuring the fluctuation amount of the instantaneous flow rate generated in each pulsation detection period;
At each end of the period of the pulsation detection period, based on a comparison result between the fluctuation amount measured by the pulsation detection period fluctuation amount measuring unit and a preset pulsation detection period fluctuation amount determination value, the pulsation detection period 2. The gas flow rate change determination device according to claim 1, further comprising: a fluctuation amount pulsation detecting unit that detects whether or not the pulsation occurs. The pulsation detecting means is
In a plurality of divided periods obtained by dividing each of a plurality of pulsation detection periods that are continuous in time series into a predetermined number of divisions, a divided period fluctuation amount measuring unit that measures a fluctuation amount of the instantaneous flow rate generated in each divided period;
At each end of the divided period, the flow rate state in the divided period is stabilized based on a comparison result between the fluctuation amount measured by the divided period fluctuation amount measuring means and a preset divided period fluctuation amount determination value. Flow rate determination means for determining whether the state is unstable or unstable;
Unstable state counting means for counting the number of the divided periods in which the flow state is determined to be unstable by the flow state determination means;
An unstable state ratio calculating means for calculating a ratio of the number of the divided periods in which the flow rate state is determined to be an unstable state to the divided number of the pulsation detection period according to the counting by the unstable state counting means;
An unstable state ratio pulsation detecting means for detecting the presence or absence of the pulsation in the pulsation detection period based on a comparison result between the ratio calculated by the unstable state ratio calculating means and a preset ratio determination value; The gas flow rate change determination device according to claim 1, wherein:

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