JP4059733B2 - Ultrasonic meter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  In the present invention, a pair of transducers are installed on the upstream side and the downstream side of a measurement channel through which fluid flows, and ultrasonic waves are transmitted between the transducers in the forward direction along the flow direction of the fluid flowing through the measurement channel. Propagation time measuring means for measuring a forward propagation time for propagating in the reverse direction and a backward propagation time for ultrasonic waves to propagate between the transducers in a direction opposite to the forward direction, and the propagation time measuring means The present invention relates to an ultrasonic meter device provided with a measuring means for deriving a flow velocity value related to the flow velocity of the fluid flowing through the measurement flow path from the forward propagation time and the backward propagation time measured by working.
[0002]
[Prior art]
  Conventionally, as a meter device used for a gas meter, a membrane type is mainly used. However, due to its convenience and the like, today, an ultrasonic flow rate or instantaneous flow rate of a fluid is measured using ultrasonic waves. The use of a sonic meter device has been proposed.
[0003]
  Such an ultrasonic meter device is provided with a pair of transducers on the upstream side and the downstream side of a measurement channel through which a fluid flows, and ultrasonic waves are transmitted in the forward direction along the fluid flow direction by the propagation time measuring means. Measures the forward propagation time t1 for propagation between the transducers and the backward propagation time t2 for the ultrasonic wave to propagate between the transducers in the opposite direction to the forward direction. The forward propagation time t1 and the backward propagation time t2 measured in this way are v, the flow velocity of the fluid along the forward direction of the measurement channel, and c the velocity of sound in the fluid in the measurement channel, When the distance between the transmitter and the receiver is d, the following equation 1 is obtained.
[0004]
[Expression 1]
  t1 = d / (c + v)
  t2 = d / (cv)
[0005]
  Therefore, the flow velocity v of the fluid flowing through the measurement channel can be obtained by the following equation 2 regardless of the sound velocity c.
[0006]
[Expression 2]
  v = (d / 2) · {(1 / t1) − (1 / t2)}
[0007]
  In other words, the measuring means has a flow rate obtained by the above equation (2) or a flow rate obtained by multiplying the flow rate by the cross-sectional area of the measurement flow channel at a predetermined measurement time interval such as a 2-second interval. For example, the flow rate value within a predetermined use period can be obtained from the flow rate value of the measurement time interval derived as described above.
[0008]
  In the ultrasonic meter device, the propagation time measuring means is from when an input signal that is an electrical signal is input to one transducer, to when an output signal that is an electrical signal is output from the other transducer. From the arrival time of, the transmission delay time from the input of the input signal in one transducer to the actual transmission of the ultrasonic wave as the acoustic signal and the ultrasonic wave as the acoustic signal in the other transducer Then, the time obtained by subtracting the delay time that is the sum of the reception delay time until the output signal is output is measured as the propagation time for the ultrasonic wave to propagate between the transducers.
[0009]
  And it is known that the delay time has temperature dependency, and the temperature dependency is caused by a subtle difference in manufacturing of the transducer.
  For this reason, in the ultrasonic meter device, a pair of transducers whose temperature dependence of the delay time is approximated is selected and installed, and the measurement means performs accurate measurement regardless of temperature. be able to.
[0010]
[Problems to be solved by the invention]
  However, in the process of using the ultrasonic meter device, there is a concern that the temperature dependency of the delay time may change over time due to deterioration of the transmitter / receiver, and the like. Due to changes over time, accurate measurement may not be possible.
[0011]
  Therefore, in view of the above-described circumstances, an object of the present invention is to realize an abnormal state determination technique for easily and accurately determining an abnormal state in which a measurement error occurs due to a temperature-dependent change in delay time.
[0012]
[Means for Solving the Problems]
  In order to achieve this object, the first characteristic configuration of the ultrasonic meter device according to the present invention is, as described in claim 1 of the claims, from the flow velocity value derived by the measuring means, A determination target flow velocity value extracting means for extracting a determination target flow velocity value maintained within a predetermined range, and a temperature of the measurement channel corresponding to the determination target flow velocity value extracted by the determination target flow velocity value extraction means A determination target temperature deriving means for deriving a determination target temperature;The delay time of the transducer is aged Based on the determination target flow velocity value corresponding to the determination target temperature in the specific temperature range that changes toIt is in the point provided with the abnormal condition determination means which determines an abnormal condition.
[0013]
  As described above in the section of the prior art, when the temperature dependence of the transmission delay time and the reception delay time in each transducer is close to each other, the measurement is performed regardless of the temperature of the measurement channel. The flow velocity value indicating the flow velocity or the flow rate measured by the means accurately indicates the flow velocity value of the fluid flowing through the measurement channel.
  However, when the temperature dependence of the delay time in each transducer is no longer approximate to each other, for example, the flow velocity value measured by the measurement means when the temperature of the measurement channel becomes a specific temperature range, The flow velocity or flow rate of the fluid flowing through the measurement channel may not be accurately indicated.
[0014]
  In addition, the inventors of the present application conducted an endurance test for a predetermined period using such an ultrasonic meter device, and the fluid in the measurement channel is in a non-flowing state (that is, no fluid is flowing through the measurement channel). In the state), before and after the endurance test, in the forward and reverse directions, when an input signal was input to one transducer, an output signal that was an electrical signal was output from the other transducer. The difference between the respective delay times in the forward direction and the reverse direction (hereinafter referred to as offsets) obtained as the difference between the respective arrival times until the time is set in a plurality of temperature ranges in which the temperature of the measurement channel is different from each other By measuring each and comparing each offset before and after the endurance test in each temperature range, it was confirmed that the temperature dependence of the transmission delay time and the reception delay time in each transducer changed.
[0015]
  That is, in the low temperature range where the temperature of the measurement channel is about −20 ° C. to 20 ° C., the offset before and after the endurance test was not substantially changed, whereas the temperature of the measurement channel is a high temperature of about 60 ° C. In the region, it was confirmed that the offset before and after the durability test was changed by an amount corresponding to about 50 L / h in terms of flow rate. From this, it can be said that the temperature dependence of the delay time has changed over time, and in particular, the delay time has changed when the temperature of the measurement channel is in the high temperature range.
[0016]
  And, the inventors of the present invention change the temperature dependence of the delay time over time, in particular, the delay time in a specific temperature range changes over time, and the delay time in other temperature ranges almost changes over time. In view of the above, the present invention relating to an abnormal state determination technique for simply and accurately determining an abnormal state in which a measurement error occurs due to a temperature-dependent change in delay time is completed.
[0017]
  That is, according to the ultrasonic meter device having the above first characteristic configuration, the flow velocity value of the fluid in the measurement flow path is maintained in a stable state within a predetermined range such as near 0 by the determination target flow velocity value extracting means. When it is recognized that the flow rate has been determined, the flow velocity value derived by the measurement means is extracted as the determination target flow velocity value. On the other hand, the temperature of the measurement channel corresponding to the determination target flow velocity value extracted by the determination target flow velocity value extraction unit, that is, the flow velocity value of the measurement channel is maintained within a predetermined range by the determination target temperature deriving unit. The temperature at the time can be derived as the determination target temperature.
[0018]
  The determination target flow velocity value obtained in this manner is between the transmitter and the receiver measured by using the propagation time measurement means when the flow velocity value of the measurement channel is maintained in a stable state within a predetermined range. Is derived on the basis of the forward propagation time and the backward propagation time of the ultrasonic wave. Therefore, when the temperature dependency of both delay times is relatively approximate to the initial state, the determination target flow velocity value should be a value that hardly depends on the determination target temperature. When the temperature dependency of the is changed, the determination target flow velocity value is a value dependent on the determination target temperature.
[0019]
  Therefore, the abnormality determination means analyzes the correlation between the determination target flow velocity value and the determination target temperature in the stable state obtained as described above, for example, a difference between at least two determination target flow velocity values having different determination target temperatures. When the determination target flow velocity value and the determination target temperature have a correlation more than an allowable level, such as when the difference is more than a tolerance, as described above, the temperature dependency of both delay times changes. The abnormal state in which the flow velocity value measured by the measurement means may not accurately represent the flow velocity or flow rate of the fluid flowing through the measurement flow path can be determined.
[0020]
  Therefore, to realize an ultrasonic flow meter that can easily and accurately determine an abnormal state in which a measurement error occurs due to a temperature-dependent change in delay time in transmission and reception of ultrasonic waves of both transducers. Can do.
[0021]
  The second characteristic configuration of the ultrasonic meter device according to the present invention is that, in addition to the first characteristic configuration, the measuring means is within a predetermined set time as described in claim 2 in the claims. The average value of the instantaneous flow velocity values derived by operating the propagation time measuring means at predetermined measurement time intervals is derived as the flow velocity value.
[0022]
  The flow velocity value of the measurement channel may be in an unstable state to which relatively high-frequency noise is added due to fluid pressure fluctuation, etc., and the determination used for the abnormal state determination from such a flow velocity value. When the target flow velocity value is extracted, there is a concern that the abnormal state is erroneously determined due to the fluctuation of the instantaneous value due to the noise.
[0023]
  Therefore, according to the ultrasonic meter device having the second characteristic configuration, the instantaneous flow velocity of the fluid flowing through the measurement flow path by using the measurement means by using the pre-propagation time measurement means at the measurement time interval such as an interval of 2 seconds. Alternatively, an instantaneous flow velocity value indicating an instantaneous flow rate is derived, and at each set time such as 30 seconds, an average value of instantaneous flow velocity values derived within the set time is derived as a flow velocity value. The flow velocity value is relatively stable with the high frequency noise cancelled. Therefore, the abnormality determination means can accurately determine the abnormal state by avoiding the erroneous determination using the determination target flow velocity value which is a stable flow velocity value.
[0024]
  The third characteristic configuration of the ultrasonic meter device according to the present invention is connected to the downstream side of the measurement flow channel in addition to the second characteristic configuration, as described in claim 3 in the claims. When the minimum flow rate of the fluid consumed during operation of the consumer device is equal to or higher than a predetermined lower limit flow rate, the measurement means derives the maximum value and the minimum value of the plurality of instantaneous flow velocity values together with the flow velocity value. The determination target flow velocity value extracting means is configured such that the flow velocity value derived by the measuring device is less than a set flow velocity value corresponding to the lower limit flow rate, and the maximum value derived by the measuring device is When the amount of change, which is the difference from the minimum value, is less than a predetermined set amount of change, the flow rate value is extracted as the determination target flow rate value.
[0025]
  In such an ultrasonic meter device, particularly an ultrasonic meter device used in a gas meter provided in each home, etc., the minimum flow rate of gas consumed by a consumer device such as a gas device connected to the downstream side of the measurement channel during operation For example, the minimum flow rate of the gas consumed by the ignition or the like may be equal to or higher than a predetermined lower limit flow rate such as 10 L / h.
[0026]
  If the flow rate is lower than the set flow rate value corresponding to the lower limit set flow rate below the minimum flow rate, there is a low possibility that the downstream consumer device is operating, and therefore the fluid is circulating in the measurement channel. There is a high possibility that the flow velocity value of the actual measurement channel is zero.
[0027]
  Further, when the measuring means derives an average value of a plurality of instantaneous flow velocity values at a predetermined set time as a flow velocity value, even if the flow velocity value is less than the set flow velocity value as described above, the set time In some of the time zones, the device may be in an operating state and fluid may have flowed through the measurement channel.
[0028]
  Therefore, according to the ultrasonic meter device of the third characteristic configuration, the consumption device in which the flow velocity value derived by the measurement means is connected to the downstream side of the measurement flow path by the determination target flow velocity value extraction means. Of the instantaneous flow velocity value within each set time that is less than the set flow velocity value corresponding to the lower limit set flow rate that is equal to or lower than the minimum flow rate of the fluid consumed during the operation and is derived by the measurement means corresponding to the flow velocity value. When the difference between the maximum and minimum values, that is, the amount of change in the instantaneous flow velocity value within the set time is less than the very small set change amount, the operation of the device is always stopped within the set time, Assuming that the flow velocity value is always maintained near 0, the flow velocity value can be extracted as the determination target flow velocity value.
[0029]
  Therefore, the measurement error of the measuring means occurs due to the temperature dependence of the delay time in the transmission and reception of the ultrasonic waves of both transducers, and the flow velocity value of the measurement channel is maintained in a stable state almost zero. Even if the flow velocity value measured by the measurement means is a value slightly deviating from 0, the determination target flow velocity value extraction means uses the flow velocity value, the maximum value, and the minimum value, and relatively accurately The determination target flow velocity value can be extracted.
[0030]
  According to a fourth characteristic configuration of the ultrasonic meter device according to the present invention, in addition to the third characteristic configuration, the determination target temperature deriving means includes the determination The determination target temperature is derived using one or both of the forward propagation time and the backward propagation time used to derive the target flow velocity value.
[0031]
  When the actual flow velocity or flow rate of the fluid in the measurement channel is maintained in the vicinity of 0, the forward propagation time or the backward propagation time measured by the propagation time measuring means at that time is the column of the prior art described above. As shown in the equation shown in Equation 1, the distance between the transmitter and the receiver is divided by the speed of sound in the measurement channel. Further, since this speed of sound is a function of the temperature of the measurement channel, the fluid flows. The determination target temperature of the measurement flow channel when not measured can be derived from the forward propagation time or reverse propagation time and the distance between the transmission and reception waves.
  Therefore, according to the ultrasonic meter device having the fourth characteristic configuration, the determination target temperature deriving unit is in a so-called stable state in which the flow velocity value is always maintained in the vicinity of 0 by the determination target flow velocity value extraction unit. When judged, the forward propagation time and backward propagation time used to derive the judgment target flow velocity value, which is the temperature when the flow velocity value in the measurement channel was the steady state flow velocity value, Using one or both of the above, it can be easily calculated as described above.
[0032]
  The fifth feature configuration of the ultrasonic meter device according to the present invention is that, in addition to the first to fourth feature configurations, the abnormality determining means includes a plurality of abnormality determining means as described in claim 5 of the claims. The determination target flow velocity value is classified into a plurality of temperature ranges using the determination target temperature, and the abnormal state is based on a difference between the temperature ranges of the determination target flow velocity values classified according to the temperature ranges. It is in the point comprised so that it may determine.
[0033]
  That is, according to the ultrasonic meter device of the fifth characteristic configuration, the abnormality determination unit converts a plurality of determination target flow velocity values into a plurality of temperature ranges such as a low temperature range and a high temperature range using the determination target temperature. Separately categorized, the delay time in the transmission and reception of ultrasonic waves of both transducers is assumed to change over time, and the target flow velocity value in a temperature range such as a high temperature range, and the delay time does not change much over time. By analyzing the difference from the flow velocity value to be judged in the temperature range such as the low temperature range, the temperature dependence of both delay times changes when the difference exceeds the tolerance, and the measurement The abnormal state can be determined on the assumption that the flow velocity value measured by the means may not accurately represent the actual flow velocity or flow rate of the measurement channel.
[0034]
  Further, as in the third feature configuration, when the determination target flow velocity value extraction unit extracts the determination target flow velocity value that is always maintained near 0, the abnormality determination unit includes the ultrasonic waves of both transducers. The flow velocity value to be judged in a temperature range such as a high temperature range in which the delay time in transmission and reception of the sensor is assumed to change over time is not changed over time, and the fluid is circulating in the measurement channel. It is determined whether or not the determination target flow velocity value in a stable state, that is, near zero, and the determination target flow velocity value in a temperature region such as a high temperature region is a value deviating from zero in the abnormal state. It can also be determined that there is.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
  An embodiment of an ultrasonic meter device according to the present invention will be described with reference to the drawings.
  FIG. 1 shows a situation in which the flow rate measurement of the gas f flowing through the measurement flow path 2 is performed by the ultrasonic meter device 1 of the present embodiment (hereinafter simply referred to as the device 1 of the present invention). .
  A gas f that is a flow rate measurement target fluid flows into the measurement channel 2 from the introduction unit 3 and is discharged from the derivation unit 4. That is, in the same figure, the flow direction of the gas f in the measurement flow path 2 is a direction from left to right.
[0036]
  The device 1 of the present invention includes a pair of transducers 5 installed on the upstream side and the downstream side of the measurement channel 2 and a control device 10 connected to the transducers 5.
[0037]
  The transducer 5a installed upstream of the measurement channel 2 and the transducer 5b installed downstream of the measurement channel 2 are installed opposite to each other at a distance d. The facing direction and the flow direction of the gas f flowing through the measurement channel 2 form an angle θ.
[0038]
  In addition, when an input signal, which is an electrical signal, is input from the control device 10, the transducer 5 transmits an ultrasonic wave, which is an acoustic signal, toward the other transducer 5 side, and further, the other transducer is received. When an ultrasonic wave transmitted from the device 5 side is received, an output signal that is an electric signal is output to the control device 10.
[0039]
  The control device 10 is configured by a computer including a timer 17, a storage unit 18 including a memory or a hard disk, an output unit 19 including a liquid crystal display unit, and the like, and when the computer executes a predetermined program, It functions as various means such as a propagation time measurement means 11, a measurement means 12, a determination target flow velocity value extraction means 13, a determination target temperature derivation means 14, an abnormality determination means 15 and the like which will be described later.
[0040]
  The propagation time measuring means 11 in which the control device 10 functions is a forward delay from the time from when the input signal is input to the upstream transducer 5a to when the output signal is output from the downstream transducer 5b. The time obtained by subtracting the time is measured as a forward propagation time t1 in which the ultrasonic wave propagates between the transducers 5 in the forward direction along the flow direction of the gas f flowing through the measurement flow path 2, and the downstream transmission / reception wave The time obtained by subtracting the reverse delay time from the time from when the input signal is input to the transmitter 5b until the output signal is output at the upstream transducer 5a is the reverse direction opposite to the forward direction. The ultrasonic wave is configured to be measured as a backward propagation time t <b> 2 for propagating between the transducers 5.
  Note that the forward and reverse delay times are the transmissions from the input of the input signal in one transducer in the forward and reverse directions to the actual transmission of the ultrasonic wave as an acoustic signal. It is the sum of the delay time and the reception delay time from the reception of the ultrasonic wave, which is an acoustic signal in the other transducer, to the output of the output signal. These delay times are measured when the device 1 of the present invention is manufactured. It has been done.
[0041]
  Further, as shown in the process flow diagram of FIG. 2, the propagation time measuring means 11 uses the timer 17 to measure such forward propagation time t1 and backward propagation time t2 at intervals of 2 seconds (measurement). (Example of time interval) is executed (# 101).
  Further, the measuring unit 12 in which the control device 10 functions uses the following formula 3 from the forward propagation time t1 and the backward propagation time t2 measured by the propagation time measuring unit 11 and stored in the storage unit 18. Thus, the instantaneous flow velocity v of the gas f flowing through the measurement flow path 2 is obtained, and the instantaneous flow speed v itself or the instantaneous flow speed v multiplied by the cross-sectional area of the measurement flow path 2 is derived as the instantaneous flow velocity value q. (# 102).
  Then, the forward propagation time t1 and the direction propagation time t2 measured by the propagation time measuring means 11 and the instantaneous flow velocity value q derived by the measuring means 12 are stored in the storage unit 18 at intervals of 2 seconds.
[0042]
[Equation 3]
  v = v ′ / cos θ = (d / 2 cos θ) · {(1 / t1) − (1 / t2)}
[0043]
  In addition, as shown in the process flow diagram of FIG. 3, the measuring means 12 calculates the average of the 15 instantaneous flow velocity values q derived at intervals of 2 seconds within 30 seconds every 30 seconds (an example of the set time). Value is the flow velocity value q_aveAnd a maximum value q from a plurality of instantaneous flow velocity values q within 30 seconds._maxAnd the minimum value q_minAre extracted (# 201).
[0044]
  Next, the determination target flow velocity value extraction means 13 on which the control device 10 functions is the flow velocity value q derived by the measurement means 12._aveIs maintained in a stable state within a predetermined range, and when it is determined that the state is stable, the flow velocity value q_aveIs extracted as the determination target flow velocity value Q.
  That is, the determination target flow velocity value extraction unit 13 firstly calculates a flow velocity value q derived by the measurement unit 12 every 30 seconds._aveIs a range less than the set flow velocity value A corresponding to the lower limit set flow rate of about 10 L / h, which is less than the minimum flow rate of gas consumed by, for example, a spark during operation of the gas equipment connected to the downstream side of the measurement channel 2 It is determined whether the current state is a stable state (# 202).
[0045]
  Further, the determination target flow velocity value extracting means 13 is configured to output the flow velocity value q_aveIs determined to be less than the set flow velocity value A, the maximum value q derived by the measuring means 12_maxAnd the minimum value q_minIt is determined whether the amount of change, which is the difference between the two, is less than a predetermined set change amount B corresponding to a very small 3 L / h or the like (# 203).
[0046]
  Then, the determination target flow velocity value extracting means 13 is configured to output the flow velocity value q_aveIs less than the set flow velocity value A and the change amount is less than a predetermined set change amount B, the operation of the gas device is always stopped within 30 seconds, and the gas f in the measurement channel 2 It is determined that the instantaneous flow velocity value q is always kept stable in the vicinity of 0, and the flow velocity value q at that time_aveIs extracted as the determination target flow velocity value Q (# 204).
[0047]
  The determination target temperature deriving unit 14 that the control device 10 functions is the flow velocity value q by the determination target flow rate value extracting unit 13 as described above._aveIs extracted as the determination target flow velocity value Q, the determination target temperature T that is the temperature of the measurement flow path 2 is derived (# 205).
[0048]
  Specifically, when the determination target flow velocity value extraction unit 13 extracts the determination target flow velocity value, the determination target temperature derivation unit 14 uses the forward propagation time t1 and the reverse propagation time used to derive the determination target flow velocity value Q. t2 is extracted from the storage unit 18, and the determination target temperature T is derived using the forward propagation time t1 and the backward propagation time t2.
[0049]
  That is, the forward propagation time t1 and the backward propagation time t2 measured when the instantaneous flow velocity value q of the gas f in the measurement channel 2 is always maintained in a stable state in the vicinity of 0, respectively, As shown in the equation, the distance d between the transducers is divided by the speed of sound c in the measurement channel.
[0050]
[Expression 4]
  t1 = d / c
  t2 = d / c
[0051]
  On the other hand, the sound velocity c is a function of the temperature T of the measurement channel 2 as shown in the following equation (5).
[0052]
[Equation 5]
  c = 392.2 + 0.64 · T
[0053]
  Therefore, the determination target temperature deriving unit 14 can derive the determination target temperature T using one or both of the forward propagation time t1 and the reverse propagation time t2 as shown in the following equation (6). .
[0054]
[Formula 6]
  T = {d / t1-392.2} /0.64
        = {D / t2-392.2} /0.64
        = [(D / 2) · {(1 / t1) + (1 / t2)}] / 0.64
[0055]
  Note that the determination target temperature deriving unit 14 may be configured to detect the determination target temperature T using a temperature sensor provided in the measurement flow path 2.
[0056]
  Furthermore, although the details will be described later, the control device 10 stores the determination target data (Q, T) of the determination target flow velocity value Q and the determination target temperature T in the storage unit 18 by the abnormality determination unit 15. At the same time, a classification process for classifying into a plurality of temperature ranges using the determination target temperature T is executed (# 206), and this processing flow ends.
[0057]
  Next, the abnormality determination means 15 in which the control device 10 functions is used when the determination target flow velocity value Q stored in the storage unit 18 and the determination target temperature T have a correlation more than an acceptable level. There is a possibility that the temperature dependence of the transmission delay time and the reception delay time changes, and the instantaneous flow velocity value q measured by the measuring means 12 does not accurately represent the actual instantaneous flow velocity value of the gas f flowing through the measurement flow path 2. It is assumed that there is an abnormal state, and the detailed processing flow will be described with reference to FIGS. 4 and 5.
[0058]
  First, as described above, the abnormality determination unit 15 executes the classification process shown in FIG. 4 when the determination target data (Q, T) is derived every 30 seconds (an example of a set time).
[0059]
  That is, the abnormality determination means 15 first refers to the determination target temperature T of the determination target data (Q, T), and uses this determination target data (Q, T) as the first temperature range (T ≦ T1), the first 2 temperature ranges (T1 <T ≦ T2),..., Nth temperature range (Tn-2 <T ≦ Tn-1), nth temperature range (Tn-1 <T) (# 301 to # 304).
[0060]
  And the average value Q of the determination target flow velocity values Q classified according to the temperature range₁, Q₂, Q_n-1, Q_nAnd the number N of judgment target data classified by temperature range₁, N₂, N_n-1, N_n(# 305 to # 308), and the average value Q of the determination target flow velocity values Q in each temperature range₁, Q₂, Q_n-1, Q_nAnd the above number N₁, N₂, N_n-1, N_nAre registered and updated in the data table of the average value and the number of data for each temperature range constructed in the storage unit 18 (# 309).
[0061]
  The plurality of temperature ranges for classifying the determination target data are, for example, two temperatures: a first temperature range where the determination target temperature T is less than a predetermined temperature such as less than 40 ° C. and a second temperature range which is equal to or higher than the predetermined temperature. Even if it is a range, for example, it may be a plurality of temperature ranges obtained by dividing a predetermined temperature range such as −10 ° C. to 60 ° C. at predetermined temperature intervals such as 10 ° C.
[0062]
  Further, the abnormality determination unit 15 calculates the average value Q in each temperature range calculated as described above and stored in the storage unit 18 for each predetermined determination period.₁, Q₂, Q_n-1, Q_nAnd the above number N₁, N₂, N_n-1, N_nAre used to execute the abnormal state determination process shown in FIG.
[0063]
  That is, the abnormality determination unit 15 firstly, at the end of a predetermined determination period such as one month, from the data table constructed in the storage unit 18, the data (Q₁, N₁), (Q₂, N₂), (Q_n-1, N_n-1), (Q_n, N_n) Is extracted (# 401).
[0064]
  Then, from the data in each temperature range, the average value Q in the low temperature range where a sufficient number of data exists._XAnd the average value Q in the high temperature range_YExtract the data.
  That is, the average value Q in the low temperature range where a sufficient number of data exists._XIn order to extract X, incrementing X one by one from 1 (# 402, # 406), N_XIs equal to or greater than a predetermined set number C such as 100 (# 403), and the number N_XIs an average value Q that is more than the set number C_XIs the average value in the low temperature range.
  On the other hand, the average value Q in the high temperature region where a sufficient number of data exists_Y, While decreasing Y one by one in order from n (# 407, # 410), N_YIs equal to or greater than a predetermined set number C such as 100 (# 408), and the number N_YIs an average value Q that is more than the set number C_YIs the average value in the high temperature range.
[0065]
  In addition, the average value Q of the low temperature range of the low temperature range_XAnd average value Q in high temperature range_YWhen X becomes n or when Y becomes 1, it is assumed that there is not a sufficient number of data in the data in each temperature range, and the abnormality determination cannot be performed with high accuracy. Then, the abnormality determination process ends (# 405, # 409).
[0066]
  In addition, the average value Q of the low temperature range of the low temperature range_XAnd average value Q in high temperature range_YIf X = Y, the average value Q in the low temperature range is extracted._XAnd average value Q in high temperature range_YAre the same data and cannot be compared, and this abnormality determination process is terminated (# 411).
[0067]
  Next, the abnormality determination unit 15 determines the average value Q of the determination target flow velocity values Q in different temperature ranges._X, Q_YThe average value Q of the high temperature range derived as above when_YAnd average value Q in the low temperature range_XThe absolute value Qd of the difference is obtained (# 412), and it is determined whether the absolute value Qd is equal to or larger than a predetermined tolerance D corresponding to 3 L / h (# 413). If the tolerance is greater than or equal to D, the average value Q of the determination target flow velocity values Q in the low temperature range_XAnd average value Q of judgment target flow velocity value Q in high temperature range_YHas a difference greater than or equal to a predetermined tolerance D corresponding to 3 L / h or the like depending on the temperature, so that the temperature dependence of the delay time of the transducers 5 changes, and the measurement is performed in a high temperature range. The instantaneous flow velocity value q measured by the measurement means 12 when the gas f is not flowing in the flow path 2 is shifted from the so-called zero point, and the instantaneous flow velocity value q measured by the measurement means 12 is not an accurate value. It is determined that there is a possibility that it is an abnormal state, and for example, an abnormality notification process is performed by outputting a message indicating that the state is abnormal to the output unit 19 (# 415).
[0068]
  On the other hand, the absolute value Qd is less than the tolerance D, and the average value Q of the determination target flow velocity values Q in the low temperature range._XAnd average value Q of judgment target flow velocity value Q in high temperature range_YAre substantially the same value, the temperature dependence of the delay time of each transducer 5 is approximate, and the instantaneous flow velocity value q measured by the measuring means 12 is an accurate value. Since the determination can be made, all the data used so far is reset to 0 without executing the abnormality notification process (# 414), and the abnormality determination process is terminated.
[Brief description of the drawings]
FIG. 1 is a diagram showing a situation where a flow velocity value is measured by an ultrasonic meter device.
FIG. 2 is a processing flow diagram showing propagation time measurement and instantaneous flow velocity value derivation processing.
FIG. 3 is a process flow diagram showing a determination target flow velocity value and a determination target temperature derivation process.
FIG. 4 is a processing flowchart showing classification processing.
FIG. 5 is a process flow diagram showing an abnormal state determination process.
[Explanation of symbols]
1: Ultrasonic meter device (device of the present invention)
2: Measurement channel
5: Transceiver
104: Control device
11: Propagation time measurement means
12: Measuring means
13: Determination target flow velocity value extraction means
14: Determination target temperature deriving means
15: Abnormality determination means
18: Storage unit
f: Gas (fluid)

Claims (5)

A pair of transducers are installed on the upstream side and downstream side of the measurement channel through which the fluid flows, and the order in which the ultrasonic waves propagate between the transducers in the forward direction along the flow direction of the fluid flowing through the measurement channel. Propagation time measurement means for measuring the direction propagation time and the reverse propagation time in which the ultrasonic wave propagates between the transducers in the reverse direction opposite to the forward direction, and the measurement was performed by using the propagation time measurement means An ultrasonic meter device comprising measurement means for deriving a flow velocity value related to the flow velocity of the fluid flowing through the measurement flow path from the forward propagation time and the backward propagation time,
A determination target flow velocity value extraction means for extracting a determination target flow velocity value maintained within a predetermined range from the flow velocity value derived by the measurement means;
Determination target temperature deriving means for deriving a determination target temperature that is the temperature of the measurement channel corresponding to the determination target flow velocity value extracted by the determination target flow velocity value extraction means;
An ultrasonic type comprising an abnormal state determination means for determining an abnormal state based on the determination target flow velocity value corresponding to the determination target temperature in a specific temperature range in which the delay time of the transducer changes with time. Meter device.   2. The apparatus according to claim 1, wherein the measurement unit is configured to derive an average value of instantaneous flow velocity values derived by operating the propagation time measurement unit at predetermined measurement time intervals within a predetermined set time as the flow velocity value. The ultrasonic meter device according to the description. In the case where the minimum flow rate of the fluid consumed during operation of the consumer device connected to the downstream side of the measurement channel is equal to or higher than a predetermined lower limit flow rate,
The measuring means is configured to derive a maximum value and a minimum value of the plurality of instantaneous flow velocity values together with the flow velocity value;
The determination target flow velocity value extraction means is such that the flow velocity value derived by the measurement means is less than a set flow velocity value corresponding to the lower limit flow rate, and the maximum value and the minimum value derived by the measurement means The ultrasonic meter device according to claim 2, wherein the flow rate value is extracted as the determination target flow rate value when a change amount as a difference is less than a predetermined set change amount.   The determination target temperature deriving means is configured to derive the determination target temperature using one or both of the forward propagation time and the backward propagation time used to derive the determination target flow velocity value. The ultrasonic meter device according to claim 3.   The abnormality determining means classifies the plurality of determination target flow velocity values into a plurality of temperature ranges using the determination target temperatures, and the difference between the temperature ranges in the determination target flow velocity values classified according to the temperature ranges. The ultrasonic meter device according to any one of claims 1 to 4, wherein the ultrasonic meter device is configured to determine the abnormal state based on the condition.

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