JP2008286681A - Flow measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow measuring device that accurately detects abnormal flow rate change and announces the abnormality. <P>SOLUTION: A flow measuring device 1 has: a measuring means 11a having a plurality of measurement modes at different measurement periods and measuring the flow rate of a fluid at the measurement period corresponding to an arbitrary selected measurement mode; a selecting means 11b for selecting a measurement mode having shorter measurement period when the variation of measurement values by the measuring means 11a satisfied the mode switching conditions for high precision mode of the selected measurement mode, and selecting a measurement mode having longer period when the variation of measuring values by the measuring means 11a satisfies the switching conditions for low precision mode of the selected measurement mode; an abnormal change determining means 11c for determining whether the variation of measurement values by the measuring means 11a at the measurement mode having the shortest measurement period satisfies the predetermined abnormal change conditions; and an abnormal change announcing means 11d for announcing abnormality according to the determination by the abnormal change determining means 11c. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flow rate measurement device for a fluid such as gas or water, and more particularly to a flow rate measurement device that performs measurement using ultrasonic waves.

  2. Description of the Related Art Conventionally, a flow rate measuring device that measures the flow rate of a fluid such as gas or water using ultrasonic waves is, for example, propagation of ultrasonic waves between an ultrasonic transmission unit and a reception unit that are arranged to face each other along a fluid flow path The flow rate of the fluid is measured from the time, and the gas flow rate is obtained from the relationship between the flow rate and the cross-sectional area of the gas pipe. And the measurement by ultrasonic can instantly determine the flow rate, and if there is a pulsation in the fluid when measured at a fixed period, the measured value will fluctuate (ie, variation) and the flow rate can be measured accurately. Therefore, when measurement values vary widely, the measurement cycle to be performed within a given period is shortened.In other words, the measurement frequency is increased to increase the accuracy, thereby preventing the measurement accuracy from deteriorating and accurately measuring the flow rate. Was realized.

The flow rate measurement device disclosed in Patent Document 1 includes a normal measurement mode for measuring the flow rate of a fluid to be measured such as gas at a predetermined interval, a first variation value measurement mode for measuring at a higher frequency than the normal measurement mode, and a first The second variation value measurement mode for measuring at a higher frequency than the first variation value measurement mode is provided, and measurement is performed by switching each measurement mode in accordance with the flow rate variation. Then, the number of measurements in each measurement mode within a certain period is counted, and the ratio of the number of measurements in each measurement mode to the total number of measurements within a certain period (that is, the measurement ratio) is calculated, and the highest measurement accuracy When the measurement ratio in the second fluctuation value measurement mode exceeds a predetermined reference value, abnormal flow fluctuation in which measurement stability (that is, measurement accuracy) cannot be obtained even in measurement in the second fluctuation value measurement mode The occurrence of abnormality was reported as having occurred.
JP 2006-105890 A

  However, when the measurement ratio of the second variation value measurement mode with the highest measurement accuracy exceeds a predetermined reference value, that is, when the number of measurements in the second variation value measurement mode is large, the measurement is not necessarily stable. It cannot be said that there was an abnormal flow rate fluctuation that could not be obtained. For example, even if a flow rate fluctuation that is sufficiently accurate in the measurement in the second fluctuation value measurement mode has occurred, measurement accuracy can be obtained. There was a problem that the occurrence of abnormality was reported as being absent, that is, it was erroneously reported.

  Accordingly, an object of the present invention is to provide a flow rate measuring device that accurately detects abnormal flow fluctuations in a measurement mode with the highest measurement accuracy and notifies the abnormality in a fluid flow rate measuring device using ultrasonic waves. There is.

  In order to solve the above problems, the flow rate measuring device according to claim 1 made according to the present invention has a plurality of measurement modes with different measurement cycles and is arbitrarily selected as shown in the basic configuration diagram of FIG. The measurement unit 11a that measures the flow rate of the fluid at the measurement cycle corresponding to the measurement mode, and the high-precision mode switching condition corresponding to the measurement mode in which the variation amount of the measurement value by the measurement unit 11a is currently selected. When the measurement mode with a shorter measurement cycle is selected and the variation amount of the measurement value by the measurement means 11a satisfies the low-accuracy mode switching condition corresponding to the currently selected measurement mode, the measurement In the flow measurement device 1 having a selection unit 11b for selecting a measurement mode with a longer cycle, the measurement unit 11a in the measurement mode with the shortest measurement cycle is used. An abnormal fluctuation determining means 11c for determining that the fluctuation amount of the measured value satisfies a predetermined abnormal fluctuation condition, and an abnormality notifying means 11d for notifying the abnormality in accordance with the determination of the abnormal fluctuation determining means 11c. It is characterized by this.

  As shown in the basic configuration diagram of FIG. 1, the flow rate measuring device according to claim 2 is the flow rate measuring device according to claim 1, and measures the measurement ratio of the measurement mode with the shortest measurement cycle within a predetermined period. The abnormality ratio determining means 11e for determining that the measurement ratio satisfies a predetermined abnormality ratio condition, and the abnormality notifying means 11d is configured to determine the abnormality variation determining means and the abnormality ratio determining means 11e. It is a means which notifies abnormality according to this determination.

  According to the flow rate measuring apparatus of the present invention as set forth in claim 1, an abnormality is notified when the amount of fluctuation of the measured value by the measuring means in the measurement mode with the shortest measurement cycle satisfies a predetermined abnormal fluctuation condition. Therefore, in the measurement mode with the shortest measurement cycle, that is, the measurement mode with the highest measurement accuracy, it can be accurately detected that an abnormal flow rate fluctuation exceeding the measurement accuracy has occurred, so an accurate abnormality notification can be made. It becomes possible and can prevent misinformation.

  According to the flow rate measuring device of the present invention described in claim 2, when the abnormal variation condition is satisfied and the measurement ratio in the measurement mode with the shortest measurement cycle within the predetermined period satisfies the predetermined abnormal ratio condition. When there are few measurements in the measurement mode with the highest measurement cycle, when the abnormal variation condition is met, the abnormality is not reported and there are many measurements in the measurement mode with the highest measurement accuracy. When an abnormal variation condition is satisfied, an abnormality is reported.In other words, when the flow rate fluctuation is constantly small, if an abnormal flow rate fluctuation that exceeds the measurement accuracy occurs, an abnormality that can only be infrequent When the flow rate fluctuation is constantly large without detecting the abnormality as the detection of the abnormality, it is possible to notify the abnormality when the abnormal flow rate fluctuation exceeding the measurement accuracy occurs. Therefore, since it is possible to eliminate the detection of an abnormality that can occur only infrequently, it is possible to notify the abnormality more accurately in accordance with the actual use, and to prevent erroneous reporting.

  Next, an embodiment in which the flow rate measuring device according to the present invention is applied to a gas meter will be described with reference to FIGS.

  As shown in FIG. 1, a gas meter 1 that is a flow rate measuring device has a microprocessor (MPU) 10 that operates according to a predetermined program. As is well known, the MPU 10 includes a central processing unit (CPU) 11 that performs various processes and controls according to a predetermined program, a ROM 12 that is a read-only memory that stores programs for the CPU 11, and various data. And a RAM 13 which is a readable / writable memory having an area necessary for the processing operation of the CPU 11.

  The CPU 11 uses a program stored in the ROM 12 to (a) a first measurement mode in which measurement is performed at a predetermined measurement cycle, a second measurement mode in which measurement is performed at a measurement cycle shorter than the first measurement mode, and a second measurement mode. A measuring means having a third measuring mode for measuring at a shorter measuring period and measuring the flow rate of the fluid at a measuring period corresponding to each arbitrarily selected measuring mode; and (b) fluctuation of a measured value by the measuring means. When the high-accuracy mode switching condition corresponding to the currently selected measurement mode is satisfied, the measurement mode with the shorter measurement cycle is selected, and the variation amount of the measurement value by the measurement means is currently selected. Selection means for selecting a measurement mode having a longer measurement cycle when the low-accuracy mode switching condition corresponding to the measurement mode is satisfied; (D) measuring the measurement ratio of the measurement mode with the shortest measurement cycle; and (d) measuring the measurement ratio of the measurement mode with the shortest measurement cycle. An abnormal ratio determining means for determining that the measurement ratio satisfies a predetermined abnormal ratio condition; and (e) reporting an abnormality in accordance with the determination of the abnormal fluctuation determining means and the determination of the abnormal ratio determining means. It operates as various means such as an abnormality notification means.

  The RAM 13 stores information used in the processing of the CPU 11. Specifically, as shown in FIG. 3, the measurement mode information 13a indicating the current measurement mode and the maximum value of the measured flow rate in the third measurement mode are stored. Maximum flow rate information 13b and minimum flow rate information 13c indicating the minimum value, maximum flow rate information 13d and minimum flow rate information 13e indicating the maximum and minimum values of the measured flow rate in the current measurement mode, and the number of measurements in the third measurement mode. Various information such as third measurement mode measurement number information 13f, total measurement number information 13g indicating the total number of measurements within a certain period, and flow rate disturbance determination number 13h indicating the number of times the flow rate disturbance is detected are stored.

  The gas meter 1 further includes a memory unit 20, a flow rate sensor 21, a display unit 22, a communication unit 23, and a shutoff valve 24, and each is electrically connected to the MPU 10.

  The memory unit 20 can retain various stored data even when power supply from a battery or the like is cut off, and can be electrically erased / rewritten with a storage area for various information necessary for the processing of the CPU 11. A read-only memory (for example, EEPROM) is used.

  The memory unit 20 includes, for example, gas pipe cross-sectional area information required for calculating the flow rate, shut-off conditions for determining gas shut-off when an abnormal flow rate is detected, individual use for determining a gas appliance in use from the flow rate and its variation pattern In addition to basic information such as instrument determination information, high-precision mode switching conditions and low-precision mode switching conditions corresponding to each measurement mode, and flow rate fluctuation abnormalities in the third measurement mode, which is the measurement mode with the highest measurement accuracy Abnormal condition used for determination, abnormal ratio condition used for determining the measurement ratio abnormality in the measurement mode with the highest measurement accuracy, flow turbulence determination specified number of times for determining the flow turbulence determination, switching of measurement mode Includes judgment information such as the specified number of mode switching judgments that set the interval for making judgments, and the prescribed number of abnormal fluctuation judgments that made intervals for making abnormal flow fluctuation judgments. Various information is stored. These values are stored in the memory unit 20 in advance when the gas meter 1 is shipped. However, the present invention is not limited to this. For example, each information is rewritten after installation so as to adapt to the installation environment of the gas meter 1. It is also possible.

  As the high-accuracy mode switching conditions, switching condition values corresponding to the first measurement mode and the second measurement mode are stored, and specifically, a predetermined number of times measured in the first measurement mode or the second measurement mode, respectively. When the difference upper limit value of the maximum value and the minimum value included in the measurement value of the minute is stored and the difference exceeding the difference upper limit value is measured, the second measurement is performed if the current measurement mode is the first measurement mode. If the mode is the second measurement mode, the mode is switched to the third measurement mode, that is, the measurement mode with higher measurement accuracy. In addition, as low-accuracy mode switching conditions, condition values corresponding to the second measurement mode and the third measurement mode are stored, and specifically, predetermined values measured in the second measurement mode or the third measurement mode, respectively. If the difference lower limit value of the maximum value and the minimum value included in the measurement values for the number of times is stored and the difference lower than the difference lower limit value is measured, the first is the first measurement mode if the current measurement mode is the second measurement mode. If the measurement mode is the third measurement mode, the mode is switched to the second measurement mode, that is, the measurement mode with lower measurement accuracy. Note that the measurement mode switching condition is not limited to this, and for example, a standard deviation indicating a variation in a plurality of measurement values may be used as the switching condition.

  As the abnormal variation condition, a condition for determining the abnormal variation of the flow rate in the third measurement mode with the highest measurement accuracy is stored. Specifically, the abnormal variation condition includes a measurement value for a predetermined number of times measured in the third measurement mode. When the difference upper limit value of the maximum value and the minimum value included is stored and the difference exceeding the difference condition value is measured, it is determined that the flow rate disturbance exceeding the upper limit has occurred. In addition, the upper limit value of the flow rate turbulence ratio, which is the upper limit value of the flow rate turbulence occurrence rate within a predetermined measurement period, is stored, and when a flow rate turbulence exceeding this upper limit value of the flow rate turbulence rate is detected, abnormal flow rate fluctuations are detected. Is determined to have occurred. Note that the abnormal variation condition is not limited to this, and for example, a standard deviation of a predetermined number of measurement values may be used as the abnormal variation condition.

  As the abnormality ratio condition, a condition value for determining an abnormality in the measurement ratio in the third measurement mode with the highest measurement accuracy is stored. Specifically, in the third measurement mode for the total number of measurements within a certain period. When the measurement ratio upper limit value of the ratio of the number of times of measurement (that is, the measurement ratio) is stored and a measurement ratio exceeding this measurement ratio upper limit value is measured, the measurement ratio in the third measurement mode is abnormal, that is, It is determined that the number of measurements in the third measurement mode has been performed more times than expected.

  The flow rate sensor 21 measures the propagation time of the ultrasonic wave between the ultrasonic wave transmitting unit and the receiving unit that are arranged to face each other along the fluid flow path, and transmits the measured value to the MPU 10 as an electric signal. There is an ultrasonic transmission / reception unit and a sensor circuit unit. The MPU 10 calculates the gas flow rate from the received value, and obtains the gas flow rate from the relationship between the flow rate and the cross-sectional area of the gas piping stored in the memory unit 20. In the present embodiment, a flow rate sensor using ultrasonic waves is used. However, the present invention is not limited to this, and other sensors may be used as long as they can measure a flow velocity or a flow rate instantaneously.

  The display unit 22 is configured to include display means such as a known liquid crystal display, and receives a command from the MPU 10 via an interface circuit (not shown), and in response to this, displays an integrated flow rate display, vibration detection, gas leakage, In addition to various indications such as battery voltage drop, abnormal warning indications such as detection of abnormal flow fluctuations exceeding the measurement limit of the gas meter 1 are performed. The display unit 22 may include an LED. The LED is composed of a plurality of elements, and different types of alarms can be displayed by changing the combination of these light emission. For example, when the shut-off valve 24 is in a closed state, all the elements blink at a predetermined cycle.

  The communication unit 23 sends the flow rate measured by the gas meter 1 received from the MPU 10 and the integrated value thereof, abnormality information generated in the gas meter 1 and the like to the management center of the gas sales company via a public line such as a telephone line. It is for notification.

  The shut-off valve 24 has a valve body (not shown) and a drive circuit that drives the valve body. When the shut-off signal sent when the MPU 10 determines that the shut-off condition is satisfied, the shut-off valve 24 is provided in the gas flow path. By driving the valve seat so as to be shut off by the valve body, a supply stop state of shutting off the gas flow path is established. When a return signal is input from the MPU 10, the valve body is driven so as to open the valve seat, thereby providing a supplyable state in which the gas flow path is opened.

  The gas meter 1 configured in this way measures the amount of gas used using the flow sensor 21. Then, when a large amount of flow rate is measured, or when there has been use for a long time which is not normal (that is, when the cutoff condition is satisfied), it is determined that there is an abnormality and the cutoff valve 24 is driven. It has a safety function that shuts off the gas flow path and ensures safety.

  Next, an example of a processing outline according to the present invention executed by the CPU 11 of the gas meter 1 will be described below with reference to a flowchart shown in FIG.

  When the CPU 11 of the gas meter 1 is activated when the power is turned on, the CPU 11 initializes various information stored in the RAM 13 by setting information indicating the first measurement mode in the measurement mode information 13a, and then proceeds to step S11. . In step S11, the measurement mode information 13a is referred to, measurement is performed at a measurement cycle corresponding to the current measurement mode, the flow velocity is calculated from the average propagation time of the ultrasonic wave received from the flow sensor 21, and the flow velocity is calculated. And the current flow rate is calculated from the relationship between the gas pipe cross-sectional area. Then, after calculating the current flow rate, the total measurement count information 13g is incremented by 1, and the process proceeds to step S12.

  In this embodiment, the measurement cycle is 10 times every 2 seconds in the first measurement mode, 100 times every 2 seconds in the second measurement mode, and 200 times in every 2 seconds in the third measurement mode. That is, the flow rate calculation interval is the same, and the number of times of propagation time measurement during the flow rate calculation interval is different. Note that the measurement cycle is not limited to this, for example, 10 times every 2 seconds in the first measurement mode, 10 times per second in the second measurement mode, and every 0.5 seconds in the third measurement mode. 10 times, etc., where the flow rate calculation interval is different and the number of times of propagation time measurement performed during the flow rate calculation interval is the same, the flow rate calculation interval is different from the number of times of propagation time measurement performed during the flow rate calculation interval, Alternatively, the measurement cycle is arbitrary as long as the measurement accuracy in each measurement mode is different, such as the measurement time interval of the propagation time is different.

  In step S12, it is determined with reference to the measurement mode information 13a whether the current measurement mode is the third measurement mode with the highest measurement accuracy. If the measurement mode information 13a indicates the third measurement mode, the process proceeds to step S13 (Y in S12). If the measurement mode information 13a does not indicate the third measurement mode, the process proceeds to step S14 (N in S12). ).

  In step S13, the maximum value and the minimum value of the measurement value in the third measurement mode are updated, the number of times of measurement in the third measurement mode is counted, and the flow rate disturbance detection determination is performed. Specifically, the current flow rate acquired in step S11 is compared with the maximum flow rate information 13b in the third measurement mode. If the current flow rate is larger, the current flow rate is set as the maximum flow rate information 13b in the third measurement mode. Is stored. Then, the current flow rate acquired in step S11 is compared with the minimum flow rate information 13c in the third measurement mode stored in the RAM 13, and if the current flow rate is smaller, the minimum flow rate information 13c in the third measurement mode. Store the current flow rate as Then, after the third measurement mode measurement count information 13f is increased by 1, each time the third measurement mode measurement count information 13f reaches a predetermined flow rate turbulence determination specified count (for example, 10, 20, 30, The difference between the maximum flow rate information and the minimum flow rate information is compared with an abnormal fluctuation condition (that is, the difference upper limit value) every 10 times or the like, and when the difference exceeds the difference upper limit value, an abnormal flow rate disturbance is detected. It is determined that the flow rate turbulence determination count 13h is increased by 1. Then, the process proceeds to step S14.

  In step S14, the measurement mode is switched. The current flow rate acquired in step S11 is compared with the maximum flow rate information 13d in the current measurement mode. If the current flow rate is larger, the current flow rate is stored in the maximum flow rate information 13d in the current measurement mode. Then, the current flow rate acquired in step S11 is compared with the minimum flow rate information 13e in the current measurement mode. If the current flow rate is smaller, the current flow rate is stored as the minimum flow rate information 13e in the current measurement mode. To do.

  Then, every time the total measurement number information 13g reaches a predetermined mode switching determination prescribed number (for example, every 30 times, 60 times, 90 times, etc.), the maximum flow rate information 13d of the current measurement mode and When the difference from the minimum flow rate information 13e in the current measurement mode is compared with the high-accuracy mode switching condition (that is, the difference upper limit value) corresponding to the current measurement mode, and the difference exceeds the difference upper limit value, When the current measurement mode is the first measurement mode, the mode is switched to the second measurement mode, and when the current measurement mode is the second measurement mode, the mode is switched to the third measurement mode. Then, the difference between the maximum flow rate information 13d in the current measurement mode and the minimum flow rate information 13e in the current measurement mode is compared with the low-accuracy mode switching condition (that is, the difference lower limit value) corresponding to the current measurement mode, When the difference falls below the lower limit of the difference, the measurement mode has a lower measurement accuracy, that is, the first measurement mode when the current measurement mode is the second measurement mode, and the second when the current measurement mode is the third measurement mode. Switch to measurement mode. When the measurement mode is switched, the maximum flow rate information 13b in the third measurement mode, the minimum flow rate information 13c in the third measurement mode, the maximum flow rate information 13d in the current measurement mode, and the minimum flow rate in the current measurement mode. Each information 13e is initialized. Then, the process proceeds to step S15.

  In step S15, it is determined whether or not a period for determining occurrence of abnormal flow rate fluctuation has elapsed. Specifically, it is determined whether or not the total measurement count information 13g has reached a predetermined abnormal variation determination prescribed number (for example, 300 times), and if the abnormal variation determination prescribed count has been reached, the process proceeds to step S16 (S15). If not reached, the flow proceeds to step S11 to measure the flow rate again (N in S15).

  In step S16, occurrence of abnormal flow rate fluctuation is determined. Specifically, when the ratio of the flow rate turbulence determination number 13h to the third measurement mode measurement number information 13f (that is, the flow rate turbulence ratio) exceeds a predetermined flow rate turbulence ratio upper limit value, the process proceeds to step S17 (S16). Y), when the flow rate turbulence ratio is lower than the upper limit, the third measurement mode measurement number information 13f, the total measurement number information 13g, and the flow rate turbulence determination number 13h are initialized (that is, 0), and the process proceeds to step S11. Advance (N in S16). It should be noted that the abnormal fluctuation determination specified number, which is also the interval for initializing the total measurement count information 13g, is the flow rate disturbance determination specified number and the mode switching determination specified number so that a deviation between the flow rate disturbance determination interval and the measurement mode determination interval does not occur. It is preferable to set so as to be a common multiple of.

  In step S17, occurrence of an abnormal measurement ratio is determined. Specifically, when the ratio of the third measurement mode measurement number information 13f to the total measurement number information 13g, that is, the measurement ratio in the third measurement mode exceeds the measurement ratio upper limit value, the process proceeds to step S18 (in S17). Y) When the measurement ratio upper limit value is not exceeded, the third measurement mode measurement number information 13f, the total measurement number information 13g, and the flow rate disturbance determination number 13h are initialized (that is, 0), and the process proceeds to step S11 ( N at S17).

  In step S <b> 18, a command for displaying detection of abnormal flow rate fluctuations is sent to the display unit 22, and a signal for notifying the management center of an abnormality is sent to the communication unit 23. Then, the process shown in the flowchart ends.

  Note that step S11 in the above description corresponds to the measuring means in the claims, step S14 corresponds to the selecting means in the claims, steps S13 and S16 correspond to the abnormal variation determining means in the claims, and step S18 is abnormal. It corresponds to notifying means, and step S17 corresponds to an abnormal ratio determining means.

  Next, an operation example when an abnormal flow rate variation is detected in the gas meter 1 will be described with reference to FIG.

  In the gas meter 1, when measurement of the gas flow rate is started, first, measurement is performed in the first measurement mode with the lowest measurement accuracy. Then, the predetermined number of times of mode switching determination (for example, 30 times) is measured and the maximum value and the minimum value of the measured flow rate are stored (FIG. 5A). Then, after the measurement of the number of times, the difference between the stored maximum value and minimum value is calculated, and compared with the difference upper limit value in the first measurement mode (that is, the mode switching condition for high accuracy), the switching determination of the measurement mode is performed. If the difference upper limit is exceeded, the measurement is switched to the second measurement mode (FIG. 5B). Also in the second measurement mode, as in the first measurement mode, the maximum and minimum values of the measured flow rate are stored while measuring the number of times (FIG. 5C). Then, after measuring the number of times, the difference between the stored maximum value and minimum value is calculated, compared with the difference upper limit value in the second measurement mode (that is, the mode switching condition for high accuracy), and exceeds the difference upper limit value. If so, the measurement is switched to the third measurement mode and measurement is continued (FIG. 5D).

  In the third measurement mode, the same operation as in the first and second measurement modes described above is performed, and the flow rate disturbance determination is performed every measurement for a predetermined flow rate disturbance determination specified number of times (for example, 10 times) (FIG. 5E). Specifically, the maximum value and the minimum value of the measurement value in the measurement of the flow rate turbulence determination specified number of times are stored (FIG. 5E1), the difference between the maximum value and the minimum value is calculated, and the difference upper limit in the third measurement mode When the difference upper limit value is exceeded when compared with the value (that is, the abnormal fluctuation condition), it is determined that the flow rate disturbance exceeding the upper limit has been detected, and the flow rate disturbance determination count 13h is increased by 1 (FIG. 5E2). Then, the determination of the turbulence of the flow rate is repeated every predetermined number of times of the turbulence determination.

  Then, similarly to the above, whenever the number of measurements reaches a predetermined mode switching determination specified number of times, the measurement mode switching determination is repeatedly performed, and every time the flow rate disturbance determination specified number of times is reached in the third measurement mode, The determination of the flow rate disturbance is repeated (FIG. 5F).

  Then, the occurrence of an abnormal flow rate fluctuation is determined every measurement for a predetermined number of times of abnormal fluctuation determination (for example, 300 times) (FIG. 5G). That is, the ratio of the flow rate turbulence determination count 13h to the third measurement mode measurement count information 13f (that is, the flow rate turbulence ratio) is compared with a predetermined flow rate turbulence ratio upper limit value, and the flow rate turbulence ratio exceeds the flow rate turbulence ratio upper limit value. If it was, the flow continued to the abnormal ratio determination, and abnormal flow rate fluctuation occurred when the measurement ratio in the third measurement mode with respect to the total number of measurements exceeded the predetermined measurement ratio upper limit value. As a result, the display unit 22 and the communication unit 23 notify the occurrence of abnormality.

  As described above, according to the flow rate measuring device 1 of the present embodiment, the variation amount of the measurement value in the third measurement mode with the highest measurement accuracy satisfies the predetermined abnormal variation condition, and the measurement ratio in the third measurement mode. Since the abnormality is notified when the predetermined abnormality ratio condition is satisfied, the abnormality is not notified when the abnormal variation condition is satisfied when the measurement in the third measurement mode is small, and the abnormality is not detected in the third measurement mode. When abnormal conditions are satisfied when there are many measurements, an abnormality is reported.In other words, when abnormal fluctuations in flow rate exceeding the measurement accuracy occur when the fluctuations in the flow rate are low, the frequency is low. Abnormality notification is not performed as a possible abnormality detection, and abnormality can be notified when abnormal flow rate fluctuations exceeding the measurement accuracy occur when flow rate fluctuations are constantly high. Therefore, since it is possible to eliminate the detection of an abnormality that can occur only infrequently, it is possible to notify the abnormality more accurately in accordance with the actual use, and to prevent erroneous reporting.

  The above-described embodiments are merely representative examples of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

It is a block diagram which shows the flow volume measuring device basic composition of this invention. It is a block diagram which shows schematic structure of the flow measuring device (gas meter) of this invention. It is a part of memory map of RAM of the flow measuring device in FIG. It is a flowchart which shows an example of the process outline | summary which concerns on this invention which CPU of the flow measuring device in FIG. 2 performs. It is a time chart which shows the operation example of the flow measuring device in FIG.

Explanation of symbols

1 Flow rate measuring device (gas meter)
10 MPU
11 CPU
12 ROM
13 RAM
11a Measuring means (CPU)
11b Selection means (CPU)
11c Abnormal fluctuation determining means (CPU)
11d Abnormality notification means (CPU)
11e Abnormal ratio determining means (CPU)
21 Flow sensor

Claims (2)

A measuring unit that has a plurality of measurement modes with different measurement cycles and that measures the flow rate of the fluid at a measurement cycle corresponding to the arbitrarily selected measurement mode, and a variation amount of a measurement value by the measurement unit is currently selected. When the high-accuracy mode switching condition corresponding to the measurement mode is satisfied, the measurement mode with the shorter measurement cycle is selected, and the variation amount of the measurement value by the measurement unit is currently selected. In the flow measurement device having a selection unit that selects a measurement mode with a longer measurement cycle when the corresponding low-accuracy mode switching condition is satisfied,
An abnormal fluctuation determining means for determining that a fluctuation amount of a measurement value by the measuring means in the measurement mode with the shortest measurement cycle satisfies a predetermined abnormal fluctuation condition;
An abnormality notifying means for notifying abnormality in accordance with the determination of the abnormality fluctuation determining means. Measuring the measurement ratio of the measurement mode with the shortest measurement period within a predetermined period, and having an abnormality ratio determination means for determining that the measurement ratio satisfies a predetermined abnormality ratio condition;
The flow rate measuring device according to claim 1, wherein the abnormality notifying means is means for notifying abnormality in accordance with the determination of the abnormal fluctuation determining means and the determination of the abnormality ratio determining means.

Images