JP2018025438A - Flow rate measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate measuring device that can perform more reliable determination of a gas appliance.SOLUTION: A flow rate measuring device comprises: flow rate measuring means that measures a flow rate of gas flowing in a channel at a fixed time interval; arithmetic means that calculates a differential value between flow rate values measured at two continuous timing; holding means that temporarily holds the flow rate value and the differential value; and appliance determination means that, when a predetermined determination condition is satisfied, determines that a gas appliance that has started to operate is a specific gas appliance. When a first determination condition as the predetermined determination condition is satisfied in which in a first predetermined number of differential values from a start of the operation of the gas appliance, a second predetermined number or more of positive differential values within a first predetermined range are present, the appliance determination means determines that the gas appliance is the specific gas appliance.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for discriminating a gas appliance that has started to be used by detecting a change in a gas flow rate.

  There has been proposed a gas meter device that identifies the type of gas appliance that has started to be used on the basis of a change in the flow rate of the gas flowing in the pipe. For example, the following Patent Document 1 measures the gas flow rate at regular time intervals, and compares the obtained flow rate value change pattern with the flow rate value change pattern obtained in advance for each gas appliance. , A gas meter device for discriminating a gas appliance that has been used is disclosed. For the purpose of reference, the entire disclosure of Japanese Patent Application Laid-Open No. 2011-095200 is incorporated herein by reference.

  Patent Document 1 further proposes to improve the accuracy of discrimination by using the flow rate indicating the characteristics of the gas appliance for discrimination of the gas appliance. Patent Document 1 exemplifies an “intermediate stable flow rate” as one of the flow rates indicating the characteristics of the gas appliance. The intermediate stable flow rate is the rate of increase in flow rate that appears between the rise of the flow rate immediately after the start of use of the gas appliance and the flow rate stabilizes to a substantially constant value in the flow rate change pattern obtained at regular time intervals. It refers to the flow rate corresponding to a relatively small area. In other words, the intermediate stable flow rate is a flow rate corresponding to a flat portion that appears in the middle of an increase in the flow rate in the flow rate change pattern.

  A gas appliance that performs a slow ignition operation, typified by a fan heater, typically exhibits such a flow rate change pattern at the start of use. Therefore, the extraction of the intermediate stable flow rate from the flow rate change pattern measured at regular time intervals is useful for improving the accuracy of discrimination of gas appliances that have been used. Here, the slow ignition is an ignition operation in a state where the gas pressure is suppressed in order to moderate the flame at the time of ignition.

JP 2011-095200 A

  However, according to the study by the inventors of the present application, even if the gas appliance that has been used is a device that performs a slow ignition operation, a flat portion may not appear in the actually measured flow rate change pattern. . In such a case, depending on the detection of the pattern corresponding to the intermediate stable flow rate, it may not be possible to specify that the gas appliance that has been used is an appliance that performs a slow ignition operation.

  In the discrimination of the gas appliance based on the change in the flow rate of the gas flowing in the pipe, it is necessary to discriminate the gas appliance with higher accuracy.

  An exemplary flow rate measurement device according to the present specification includes a flow rate measurement unit that measures a gas flow rate flowing in a flow path at a constant time interval, and a calculation unit that calculates a difference value between flow rate values at two consecutive measurement timings. A holding means for temporarily holding the flow rate value and the difference value, and an appliance determination means for determining that the gas appliance that has started operation is a specific gas appliance when a predetermined determination condition is satisfied. The determination means includes, as the predetermined determination condition, in the first predetermined number of difference values from the start of operation of the gas appliance, a first determination condition in which a positive difference value within the first predetermined range is greater than or equal to a second predetermined number. If so, the gas appliance is determined to be a specific gas appliance.

  According to the flow rate measuring device of the present invention, the gas appliance can be more surely determined based on the flow rate change of the gas flowing in the pipe.

FIG. 1 is a block diagram illustrating an exemplary configuration of a gas meter 100 according to an embodiment of the present invention. FIG. 2 is a graph showing a typical example of a change in flow rate at the start of use of a gas appliance that performs a slow ignition operation. FIG. 3A is a graph showing another example of a flow rate change at the start of use of a gas appliance that performs a slow ignition operation. FIG. 3B is a graph showing still another example of the flow rate change at the start of use of the gas appliance that performs the slow ignition operation. FIG. 4 is a graph showing an example of a change in flow rate value regarding a gas appliance different from the gas appliance to be detected. FIG. 5 is a graph showing another example of a change in flow rate value regarding a gas appliance different from the gas appliance to be detected. FIG. 6 is a block diagram illustrating an example of a hardware configuration of the gas meter 100.

  First, the inventions made by the present inventors are as follows.

  A flow rate measuring device according to a first invention of the present application is a flow rate measuring unit that measures a gas flow rate flowing in a flow path at a constant time interval, and an arithmetic unit that calculates a difference value between flow rate values at two consecutive measurement timings. A holding means for temporarily holding the flow rate value and the difference value, and an appliance determination means for determining that the gas appliance that has started operation is a specific gas appliance when a predetermined determination condition is satisfied. The determination means includes, as the predetermined determination condition, in the first predetermined number of difference values from the start of operation of the gas appliance, a first determination condition in which a positive difference value within the first predetermined range is greater than or equal to a second predetermined number. If so, the gas appliance is determined to be a specific gas appliance.

  In the flow rate measuring apparatus according to the second invention of the present application, the instrument determining means has a third predetermined number measured after a plurality of flow rate values used for calculating the first predetermined number of difference values as the predetermined determination condition. The gas appliance is determined to be a specific gas appliance when the second determination condition in which the arithmetic average of the flow rate values is within the second predetermined range is further satisfied.

  In the flow rate measuring device according to the third invention of the present application, the instrument determining means has, as the predetermined determination condition, a third determination condition in which variation from the arithmetic average in the third predetermined number of flow rate values is within the third predetermined range. Is determined to be a specific gas appliance.

  In the flow measurement device according to the fourth invention of the present application, the appliance determination means obtains a plurality of moving average values from a plurality of flow values, and when the fourth determination condition is further satisfied as a predetermined determination condition, The gas appliance is determined to be a specific gas appliance, and a fourth determination condition is that a difference between two consecutive moving average values among a plurality of moving average values is a fourth predetermined range in which the difference is equal to or more than the first predetermined number of times. This is the inner condition.

  A flow rate measuring device according to a fifth invention of the present application is a conversion table holding means for holding a conversion table in which a plurality of sections corresponding to the magnitude of a difference value and inclinations determined according to the respective sections are associated with each other. And a difference value conversion means for converting the difference value into a slope based on the conversion table, and the appliance determination means includes a first predetermined number of difference values corresponding to the first predetermined number of difference values from the start of operation of the gas appliance. In the inclination, it is determined whether or not the first determination condition is satisfied by determining whether or not there is a second predetermined number or more of inclinations within the fifth predetermined range.

(Knowledge obtained by the present inventors)
Here, prior to the description of the embodiment of the flow rate measuring device according to the present invention, the problems found by the present inventors will be described.

  FIG. 2 shows a typical example of a flow rate change at the start of use of a gas appliance that performs a slow ignition operation. In FIG. 2, the vertical axis of the graph represents the flow rate value (L / h), and the horizontal axis represents the timing of measurement of the flow rate value. Here, the measurement timing is a fixed time interval (hereinafter, also referred to as “sampling interval”), and the interval (sampling interval) is, for example, 0.5 seconds.

  In the example shown in FIG. 2, the flow rate shows a relatively large increase between the measurement timings 0 and 1. This corresponds to the start of use of the gas appliance at the measurement timing 0. The flow rate shows an increase from the measurement timing 0, then shows a relatively small increase rate between the measurement timings 2 to 4, and the increase rate increases again between the measurement timings 4 and 5. Therefore, in this example, a flat portion appears between the measurement timings 2 to 4 (portion surrounded by the broken line F1) in the flow rate change pattern. This flat portion in the flow rate change pattern reflects the fact that the slow ignition operation was performed. Note that, after the measurement timing 6, the flow rate is almost constant and stable. According to the study by the inventors of the present application, after the gas appliance is ignited, a region where such a flow rate is stable generally appears in the flow rate change pattern.

  In the technique described in Patent Document 1 described above, when the flow rate change is such that the absolute value of the difference between the flow rate values between two adjacent measurement timings is 20 L / h or less, the flow rate value at that time is continuous. Is calculated as an intermediate stable flow rate. In the case of the flow rate change illustrated in FIG. 2, the average of the flow rate values at the measurement timings 3 and 4 is calculated as the intermediate stable flow rate, and is used for determining the gas appliance.

  The measurement result of the flow rate at the start of use of the gas appliance that performs the slow ignition operation ideally shows a pattern having a flat portion as shown in FIG. However, according to a detailed study by the inventors of the present application, even in a gas appliance that performs a slow ignition operation, the flow rate change pattern may not show a pattern having a flat portion.

  3A and 3B show another example of the flow rate change at the start of use of the gas appliance that performs the slow ignition operation. In these examples, attention is paid to the period from the rise of the flow rate (corresponding to the start of use of the gas appliance) to the maximum flow rate in the illustrated range. In the pattern illustrated in FIG. 3A, the flow rate shows a moderate increase with the start of use of the gas appliance (measurement timings 0 to 5), and then changes at a substantially constant level (measurement timings 7 to 16). . Therefore, a flat part is not seen in the middle of the increase in the flow rate. In the flow rate change pattern illustrated in FIG. 3B, the change rate of the flow rate increases and decreases between the measurement timings 0 to 8, but the flow rate shows a tendency to increase as a whole, and the portion corresponding to the slow ignition operation It is difficult to find clearly. When the flow rate change pattern as shown in FIG. 3A and FIG. 3B is acquired, the detection of the slow ignition operation and the calculation of the intermediate stable flow rate based on the flow rate change pattern described above by the method described in Patent Document 1 are performed. Have difficulty.

  Therefore, when the measured flow rate shows a change pattern as shown in FIGS. 3A and 3B, by detecting a characteristic change in the flow rate corresponding to the slow ignition operation, the slow ignition operation is performed. It is difficult to determine that the use of the gas appliance to be started has started. The inventors of the present invention have made extensive studies in view of the above and completed the present invention.

  Embodiments of a flow rate measuring device according to the present invention will be described below with reference to the accompanying drawings. In the embodiment described below, a gas meter is given as an example of the flow rate measuring device, and the process will be described. In the drawings, the same components are denoted by the same reference numerals, and the description of the components already described is omitted. Note that the present invention is not limited to the embodiments described below.

(Exemplary configuration of flow measurement device)
FIG. 1 shows a configuration example of a gas meter 100 according to an embodiment of the present invention. The gas meter 100 has a flow path 102 therein and is used in a state of being connected to a gas pipe 10a that supplies gas. The gas meter 100 is disposed between the gas pipe 10a and one or more gas appliances (a gas stove, a gas fan heater, a water heater, etc.). FIG. 1 shows a state in which one end of the flow path 102 of the gas meter 100 is connected to the upstream gas pipe 10a and the other end of the flow path 102 is connected to the downstream gas pipe 10b. Gas appliances 13, 14 and 15 are connected to the tube 10b.

  In the configuration illustrated in FIG. 1, the gas meter 100 schematically includes a flow rate measuring unit 104, a control unit 105, and a blocking unit 122 arranged in the middle of the flow path. The flow rate measuring unit 104 measures the flow rate of the gas flowing through the flow path 102 at regular time intervals. As the flow rate measuring means 104, for example, an ultrasonic flow meter can be applied. The ultrasonic flow meter measures the instantaneous flow rate of gas by emitting ultrasonic waves at regular time intervals to the gas flowing through the flow path 102 and obtaining a propagation time difference caused by the gas flow. By obtaining data indicating the flow rate at regular time intervals detected by the flow rate measuring means 104, it is possible to detect a change in the amount of gas used.

  In the configuration illustrated in FIG. 1, the control unit 105 includes a holding unit 106, a calculation unit 108, and an appliance determination unit 116. In the example illustrated, the control unit 105 further includes a conversion table holding unit 110 and a difference value conversion unit 112. A typical example of the operation of the gas meter 100 will be described later.

  In this example, the gas meter 100 includes a blocking unit 122 disposed between the gas pipe 10a and the flow rate measuring unit 104. The shut-off means 122 stops the gas supply to the gas appliances 13, 14 and 15 connected to the gas pipe 10 b based on the control of the control means 105 when an abnormal increase in the gas flow rate is detected. As the shut-off means 122, for example, a shut-off valve can be used.

  Based on the flow rate value acquired by the flow rate measuring unit 104, the calculation unit 108 calculates a difference value between the flow rate values at two consecutive measurement timings. That is, when the flow rate value at a certain measurement timing is Q (n) and the flow rate value at the immediately preceding measurement timing is Q (n−1), the calculation means 108 calculates the difference value D ( n) = Q (n) −Q (n−1) is calculated.

  The holding unit 106 includes instantaneous value data of the flow rate output from the flow rate measuring unit 104 (hereinafter, also referred to as “flow rate value data”), data indicating the calculation result of the above-described difference value D (n), and the like. It is a memory that stores temporarily. In addition to temporarily holding the flow rate value in the calculation of the difference value, the holding unit 106 can also temporarily hold the calculation result from the calculation unit 108, for example, the difference value obtained by the calculation. The difference value and the flow rate value may be held in a single memory, or each may be held in a separate memory. The holding means 106 includes not only a single memory but also a configuration having a plurality of memories. The holding unit 106 may be disposed inside the control unit 105 or may be disposed outside the control unit 105.

  The appliance determination unit 116 determines whether or not a predetermined determination condition is satisfied based on the difference value held in the holding unit 106. When the predetermined determination condition is satisfied, the gas appliance that has started operation is specified. It is determined that it is a gas appliance. As schematically shown in FIG. 1, data of a flow rate value acquired by the flow rate measuring unit 104 may be provided to the instrument determining unit 116. When a predetermined determination condition is satisfied, the appliance determination unit 116 determines that, for example, a gas appliance that has started operation, that is, a gas appliance that has started to be used is a gas appliance that performs a slow ignition operation.

(Example of judgment operation)
Hereinafter, an example of the determination operation of the appliance determination unit 116 will be described with reference to the drawings. As will be apparent from the following description, according to the embodiment of the present invention, in the flow rate change pattern, even if a flat portion does not appear in the middle of the increase in the flow rate at the start of operation, the slow ignition operation is performed. The start of operation of the gas appliance to be performed (for example, a fan heater) can be detected.

  As described above, the appliance determination unit 116 determines whether or not a predetermined determination condition is satisfied based on the difference value held in the holding unit 106. As will be described later, the predetermined determination condition is not limited to a single condition, and may include two or more conditions.

(First judgment condition)
The appliance determination unit 116 performs determination using a predetermined number of data among the flow rate data output from the flow rate measurement unit 104 by measuring the flow rate of the gas flowing through the flow path 102 at a constant time interval. In the first example described here, a first predetermined number of difference values from the start of operation of the gas appliance are calculated, and determination is performed using the first predetermined number of difference values.

  Refer to FIG. 3A again. FIG. 3A plots 17 flow values measured at a constant sampling interval. Table 1 below shows the flow rate value Q (n) at each measurement timing of the graph illustrated in FIG. 3A and the difference value D (n) corresponding to each flow rate value Q (n).

  The sampling interval is, for example, 0.5 seconds. In this case, FIG. 3A shows the change in gas flow rate for 8 seconds from the start of use of the gas appliance. The determination of the gas appliance based on the flow rate change pattern acquired at regular time intervals as described in Patent Document 1 is typically based on a plurality of flow rate values acquired in a period of about 8 seconds. Executed. In other words, in determining the gas appliance that has started to be used, the flow rate value over a period of about 8 seconds from the start of operation of the gas appliance (hereinafter, sometimes referred to as “determination period” for convenience of explanation). Is required. On the other hand, in the first example described here, the determination is performed using a first predetermined number of difference values obtained during a period in which the flow rate value generally increases.

  The appliance determination means 116 determines whether or not there is a second predetermined number or more of positive difference values within the first predetermined range in the first predetermined number of difference values from the start of operation of the gas appliance as a predetermined determination condition. Determine (first determination condition). Here, the determination using six difference values from the start of operation of the gas appliance as the first predetermined number of difference values is illustrated. For example, the appliance determination unit 116 operates when there are 5 or more positive difference values in the range of 0 L / h or more and 90 L / h or less in 6 difference values from the start of operation of the gas appliance. It is determined that the started gas appliance is a gas appliance that performs a slow ignition operation.

  As can be seen from Table 1, in the example shown in FIG. 3A, the difference value D (1) among the six difference values D (1) to D (6) that are continuous in time series from the start of operation of the gas appliance. ) To D (5) are all positive difference values within the above range. In other words, the positive difference value within the above range is continued four times. Therefore, when the data of the flow rate value Q (n) as shown in Table 1 is obtained, the appliance determination means 116 determines that the first condition is satisfied, and as a result, the gas appliance that has started operation becomes loose. It is determined that the gas appliance performs an ignition operation, for example, a fan heater. In this specification, “determination” by the appliance determination unit 116 includes, for example, that a value indicating a determination result is output from the appliance determination unit 116 or a value is set in a flag. The result of the determination can be written in storage means such as a memory.

  Reference is now made to FIG. Table 2 below shows the flow rate value Q (n) and the difference value D (n) at each measurement timing of the graph illustrated in FIG. 3B.

  As can be seen from Table 2, in the example shown in FIG. 3B, among the six difference values D (1) to D (6) from the start of operation of the gas appliance, the difference value D (1) continuous in time series. ~ D (6) are all positive difference values within the above range. Therefore, when the above-described first determination condition is applied, it is determined that the gas appliance that has started operating is a gas appliance that performs a slow ignition operation.

  Here, the start of operation of the gas appliance can be determined by the change in the flow rate value measured at regular time intervals indicating an increase in the predetermined range. For example, when the difference value of 10 L / h or more is obtained, the above-described determination operation may be executed. The determination as to whether or not the gas appliance performs the slow ignition operation after the start of operation of the gas appliance is detected may be executed after the first predetermined number of difference values are obtained. It may be executed in parallel with the calculation.

  In this example, whether or not the gas appliance that has started operation is a gas appliance that performs a slow ignition operation by determining whether or not the flow rate has increased in a characteristic size for the gas appliance that performs a slow ignition operation. Judging. For example, in the case of a gas leak, a more rapid increase in the flow rate value is detected, so by applying the first determination condition, the occurrence of the gas leak is erroneously determined as, for example, the start of fan heater operation. The possibility can be reduced. Further, in a gas stove in which the flow rate zone at the start of operation is close to that of a fan heater, generally, the mild ignition operation is not applied, and the flow rate rapidly increases at the start of operation. Therefore, for the same reason as in the case of gas leakage, the possibility that the operation start of the gas stove is erroneously determined as, for example, the operation start of the fan heater is reduced. Since gas appliances having close flow rates can be distinguished, the determination method of the present invention is useful for determining, for example, whether the fan heater has been used.

  Thus, according to the embodiment of the present invention, although it is a gas appliance that performs a slow ignition operation, even when the pattern of change in flow rate at the start of operation does not indicate a pattern having a flat portion, It is possible to specify that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation. The first predetermined number, the first predetermined range, and the second predetermined number in the first determination condition can be appropriately changed according to the type of gas appliance for which the operation start is desired to be detected, the sampling interval, and the like.

  In addition, about the typical example of the flow rate change pattern of the gas appliance that performs the slow ignition operation described with reference to FIG. 2, six difference values D (1) to D (6) from the start of the operation of the gas appliance are obtained. When calculated, they are 90 L / h, 55 L / h, 5 L / h, 8 L / h, 50 L / h, and -5 L / h, respectively, and five consecutive difference values D (1) to D (5 ) Are all positive difference values within the above-mentioned range. Therefore, when the first determination condition is applied as the predetermined determination condition, it is determined in the example shown in FIG. 2 that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation.

  The above-described determination operation may be executed alone, or may be applied in combination with a device determination process as described in Patent Document 1. For example, the above-described determination operation may be executed after the appliance determination process described in Patent Document 1. Thereby, the operation start of the gas appliance which performs a slow ignition operation | movement can be caught more reliably. As a first determination condition, in the first predetermined number of difference values from the start of operation of the gas appliance, it is determined whether or not the positive difference value within the first predetermined range continues for a predetermined number of times (for example, four times) or more. May be.

(Judgment using slope)
In the above-described example, it is determined whether or not the gas appliance that performs the slow ignition operation is started using the difference value calculated from the flow rate value. However, the determination is not limited to the difference value itself calculated from the flow rate value, and the determination may be performed using another amount determined based on the difference between the flow rate values at two consecutive measurement timings. For example, as will be described below, the determination may be made using a slope determined according to the absolute value of the difference value calculated from the flow rate value.

  Refer to FIG. 1 again. The gas meter 100 illustrated in FIG. 1 includes a conversion table holding unit 110 and a difference value conversion unit 112. The conversion table holding means 110 holds a conversion table 110a in which a plurality of sections corresponding to the magnitude of the difference value D (n) described above and slopes determined according to the respective sections are associated. Table 3 below shows an example of the conversion table 110a.

  The difference value conversion unit 112 obtains the difference value D (n) from the calculation unit 108 and refers to the conversion table 110a held in the conversion table holding unit 110, thereby corresponding to the difference value D (n). The inclination is converted to C (n). Data relating to the inclination C (n) corresponding to each measurement timing is passed from the difference value conversion means 112 to the instrument determination means 116.

  When using the inclination degree C (n), the appliance determination means 116 has a first predetermined number corresponding to a first predetermined number (for example, six) difference values from the start of operation of the gas appliance as a predetermined determination condition. It is determined whether or not there is a second predetermined number (for example, five) or more of inclinations within a predetermined range in the inclination C (n). For example, the appliance determination means 116 that has received data relating to the inclination C (n) has an inclination of 1 to 6 in six inclinations C (1) to C (6) from the start of operation of the gas appliance. It is determined whether 5 or more appear.

  For example, when the gradients C (1) to C (6) are obtained based on Table 1 and Table 3 for the example shown in FIG. 3A, C (1) = 5, C (2) = 5, C (3) = 4, C (4) = 4, C (5) = 3, C (6) = 1, and there are six gradients of 1-6. Therefore, when a flow rate value as shown in Table 1 is obtained, the appliance determination means 116 determines that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation.

  Similarly, when the gradients C (1) to C (6) are obtained based on Table 2 and Table 3 for the example shown in FIG. 3B, C (1) = 4, C (2) = 5, C (3) = 2, C (4) = 4, C (5) = 2, and C (6) = 3. Therefore, even when the flow rate values shown in Table 2 were obtained, the instrument determination unit 116 started operation. It is determined that the gas appliance is a gas appliance that performs a slow ignition operation. For FIG. 2, C (1) = 6, C (2) = 6, C (3) = 2, C (4) = 2, C (5) = 6, and C (6) = 2. In the same manner as in the case where the determination based on the difference value D (n) is made, it is determined that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation.

  Thus, you may perform determination using the quantity converted from the difference of the flow value of two continuous measurement timings. By making the determination by converting the difference between the flow values into the slope, it is possible to make a determination independent of the size of the gas appliance to be detected (may be referred to as the gas flow rate to be used). Moreover, the calculation load in determination can be reduced by converting the difference between the flow values into the slope and performing the determination. By appropriately setting the upper limit of the inclination, for example, when it is desired to detect the start of operation of the fan heater, it is possible to reduce the possibility of detecting the start of operation of the gas stove near the flow rate as the start of operation of the fan heater.

  In the above-described example, in the determination using the difference value D (n), the positive difference value D (n) is extracted from the calculated difference value D (n). It should be noted that in the determination using C (n), the absolute value of the difference value D (n) is converted into the gradient C (n) and used for the determination. However, both the case where the difference value D (n) is used and the case where the gradient C (n) is used are common in that the determination based on the difference between the flow rate values at two consecutive measurement timings is performed.

(Second determination condition)
In the first example described above, paying attention to the measurement timing included in the initial period of the start of operation of the gas appliance, as a predetermined determination condition, a first predetermined number of difference values (or gradients from the start of operation of the gas appliance). ) Is applied. However, the predetermined determination condition is not limited to a single condition. As described below, when other conditions are further satisfied as the predetermined determination condition, it may be determined that the gas appliance that has been used is a specific gas appliance.

  Please refer to FIG. As already described, the graph shown in FIG. 2 is a typical example of the flow rate change at the start of use of the gas appliance that performs the slow ignition operation. When attention is paid to the graph shown in FIG. 2, it can be seen that the entire period shown in FIG. 2 (measurement timings 0 to 15, corresponding to the determination period) roughly includes two periods. The first period is an initial period (measurement timing 0 to 5 in this example) in which the measured flow rate value generally increases with the start of use of the gas appliance, and the second period is the first period. Is a later period (measurement timings 6 to 15 in this example) in which the flow rate value changes at a substantially constant level. In the technique described in Patent Document 1, a “stable flow rate” is calculated as one of the instrument characteristic flows indicating the characteristics of the gas appliance from the flow rate value measured in the second period, and is used for discrimination of the gas appliance. Yes. Note that the start point and the end point of the second period may differ depending on the acquired flow rate change pattern.

  Here, a second determination condition focusing on the transition of the flow rate value in the second period is set, and it is determined whether or not the second determination condition is further satisfied in addition to the first determination condition. When the second determination condition is further satisfied in addition to the first determination condition, it is determined that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation. The second determination condition is a condition in which the arithmetic average of the third predetermined number of flow values measured after the plurality of flow values used for calculating the first predetermined number of difference values is within the second predetermined range. Can be used. In the example described here, the appliance determination unit 116 determines whether or not the second determination condition is further satisfied in addition to the first determination condition described above, and the first and second determination conditions are satisfied. In this case, it is determined that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation.

  Reference is now made to FIG. 3A. In the graph shown in FIG. 3A, 17 flow rate values obtained at measurement timings 0 to 16 are plotted. As already described, in the first example in which the first determination condition is applied, the first predetermined number (six in this case) of difference values D (6) using the flow rate values Q (0) to Q (6). 1) to D (6) are calculated. In this example, the period for acquiring the flow values Q (0) to Q (6) used for calculating the difference values D (1) to D (6) can be referred to as a first period.

  For example, the appliance determination unit 116 performs arithmetic operation on a third predetermined number of flow rate values measured after a plurality of flow rate values (here, flow rate values Q (0) to Q (6)) measured in the first period. An average, for example, an arithmetic average Ave of six flow rate values Q (11) to Q (16) is acquired, and whether the arithmetic average Ave is within a second predetermined range, for example, 90 L / h or more and 210 L / h or less. Determine. The calculation of the arithmetic average Ave may be executed by the instrument determination unit 116 or may be executed by the calculation unit 108.

  When the arithmetic average Ave of the flow rate values Q (11) to Q (16) is obtained with reference to Table 1, it is 113.5 L / h, which is in the range of 90 L / h to 210 L / h. That is, the flow rate change shown in FIG. 3A satisfies the second determination condition. As already described, the flow rate change shown in FIG. 3A satisfies the first determination condition described above. That is, since the first and second determination conditions are satisfied, the appliance determination unit 116 determines that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation. With respect to the flow rate change shown in FIG. 3B, the same determination result can be obtained by calculating the arithmetic average of the flow rate values Q (11) to Q (16) with reference to Table 2.

  As described above, the appliance determination unit 116 further determines whether or not the second determination condition is satisfied, and when the second determination condition is further satisfied, the gas appliance that has started use is specified. You may determine that it is a gas appliance. By applying a combination of two or more conditions as the predetermined determination condition, the determination accuracy can be improved. For example, when a gas leak occurs downstream of the gas meter 100, the measured flow rate value increases after the gas leak occurs, and thereafter changes at a substantially constant flow rate value. However, in the case of a gas leak, the flow value that remains substantially constant generally belongs to a larger flow rate zone than, for example, the arithmetic average Ave and the stable flow rate described above for the fan heater. Therefore, by determining whether the arithmetic average of the third predetermined number of flow values measured after the plurality of flow values measured in the first period is within the second predetermined range, the gas leakage is For example, the possibility of accidental detection as the start of operation of the fan heater can be reduced.

(Third determination condition)
As the predetermined determination condition, it may be determined whether or not the third determination condition is further satisfied. Then, when the third determination condition is further satisfied, it may be determined that the gas appliance that has been used is a specific gas appliance. As a weighted third determination condition, a variation from the above-mentioned arithmetic average Ave in a third predetermined number of flow values measured after a plurality of flow values used to calculate the first predetermined number of difference values May be applied within the third predetermined range.

For example, with respect to the flow rate change shown in FIG. 3A or the flow rate change shown in FIG. 3B, the instrument determination means 116 can calculate, for example, each of the flow rate values Q (11) to Q (16) and the arithmetic average Ave Get the sum of absolute values of the differences. That is, Σ _j | Q (j) −Ave | is acquired (j is an integer from 11 to 16). The appliance determination unit 116 determines whether or not Σ _j | Q (j) −Ave | is within the third predetermined range, for example, 30% or less of the arithmetic average Ave, and Σ _j | Q (j) −Ave. When | is within the third predetermined range, it is determined that the gas appliance that has started operation is a gas appliance that performs a slow ignition operation.

Variations from the arithmetic average Ave include Σ _j | Q (j) −Ave |, the sum of the squares of the difference between each of the third predetermined number of flow values and these arithmetic averages, or the sum thereof. An amount divided by the third predetermined number (this is equal to the sample variance) may be used. The specific numerical range of the third predetermined range may be appropriately set according to what amount is used as the variation from the arithmetic average Ave. The calculation of the variation from the arithmetic average Ave may be executed by the instrument determination unit 116 or may be executed by the calculation unit 108.

  According to the study by the inventors of the present application, the arithmetic average Ave may accidentally fall within the second predetermined range while showing a drastic fluctuation in the flow rate value in the second period. For example, depending on the gas appliance, the flow rate value may show severe fluctuations in the second period, and the second determination condition may be satisfied when focusing only on the arithmetic average of the flow rate values acquired in the second period There is sex. By determining whether or not the third determination condition is satisfied in addition to the first and second range conditions, for example, the operation start of the gas appliance different from the fan heater is erroneously determined as the operation start of the fan heater. The possibility of being lost can be reduced.

(Fourth determination condition)
Reference is now made to FIGS. FIG. 4 and FIG. 5 are graphs showing still other examples of changes in flow rate values, and show examples of changes in flow rate values related to gas appliances different from the gas appliance to be detected. In these examples, the flow rate values from the measurement timing 0 at which the flow rate value starts rising to the measurement timing 16 corresponding to the end point of the determination period are plotted.

  As can be seen with reference to FIGS. 4 and 5, in these examples, the flow rate value generally increases over the entire measurement timings 0 to 16. Table 4 and Table 5 below show the flow rate value Q (n) and the difference value D (n) at the respective measurement timings of the graph shown in FIG. 4 and the graph shown in FIG.

  Both the example shown in FIG. 4 and the example shown in FIG. 5 show behaviors different from typical changes in the flow rate value during operation of a gas appliance that performs a slow ignition operation, for example, a fan heater. However, as can be seen by referring to Tables 4 and 5, both the example shown in FIG. 4 and the example shown in FIG. There are five or more positive difference values in the range of 0 L / h to 90 L / h. Therefore, assuming that the first determination condition is satisfied, there is a possibility that the gas appliance that has started operation is erroneously determined to be a gas appliance that performs a slow ignition operation.

  Further, in these examples, the region where the flow rate value changes at a substantially constant level cannot be recognized. However, for example, when calculating the arithmetic average Ave of the six flow rate values Q (11) to Q (16) measured after the flow rate values Q (0) to Q (6), 90 L / h or more and 210 L / h, respectively. 206.0 L / h and 102.8 L / h within the range of h or less. Therefore, even if the second determination condition is further applied, there is a possibility that the gas appliance that has started operation is erroneously determined as a gas appliance that performs a slow ignition operation.

  Thus, when the flow rate value rises slowly over a relatively long period (for example, about 5 seconds to 10 seconds), or when the flow rate value change pattern draws a convex parabola, It may be advantageous to grasp the overall transition of the flow rate value during the determination period rather than part of the determination period. In the example described here, it is further determined whether or not the fourth determination condition focusing on the transition of the plurality of flow rate values obtained in the determination period is satisfied. Note that the fourth determination condition described below is not necessarily applied in combination with all of the above-described first to third determination conditions. For example, when the first and fourth determination conditions are satisfied as the predetermined determination condition, it may be determined that the gas appliance that has been used is a specific gas appliance. Alternatively, when the first, second, and fourth determination conditions are satisfied, it may be determined that the gas appliance that has been used is a specific gas appliance.

  Here, the following condition is set as the weighted fourth determination condition. Hereinafter, a specific example of the fourth determination condition will be described by describing an operation example in the gas meter 100.

  First, a plurality of moving average values (simple moving average values) are generated based on a plurality of flow rate values obtained during the determination period. The calculation of the moving average value may be executed by the appliance determination unit 116 or may be executed by the calculation unit 108. Here, an example using a four-point moving average will be described.

In the calculation of the four-point moving average value, a plurality of flow rate values obtained corresponding to a plurality of measurement timings included in the determination period, each of which has a predetermined number (here, four) of flow rate values as elements. A set is generated. The k-th set S _k is composed of four flow rate values that are continuous in time series from Q (k−1). That is, for the first set S ₁ , Q (0), Q (1), Q (2), and Q (3) are selected as elements. The second set S _2, the measurement timing one shifted four flow rate value Q (1), composed of Q (2), Q (3 ) and Q (4). In this example, since 17 flow values are obtained in the determination period, 14 sets S _{1 to} S ₁₄ are generated.

Next, a set set in which the difference between the moving average values of each of the two adjacent sets selected from the generated 14 sets is within the fourth predetermined range continues for the first predetermined number of times or more. It is determined whether or not. That is, to calculate the 14 sets S ₁ to S moving average SMA ₁ ~SMA ₁₄ for each of _14, the difference between two moving averages successive selected from these (SMA ₂ -SMA _1), ( SMA ₃ -SMA ₂ ),..., (SMA ₁₄ -SMA ₁₃ ), the difference within the fourth predetermined range, for example, −4 L / h to 4 L / h is the first predetermined number of times (for example, 4 times). It is determined whether or not it is continuous.

In the example shown in FIG. 4, the fourth predetermined range among the differences (SMA ₂ −SMA ₁ ), (SMA ₃ −SMA ₂ ),..., (SMA ₁₄ −SMA ₁₃ ) between two successive moving average values. There is no inner difference. For the example shown in FIG. 5, among the differences (SMA ₂ −SMA ₁ ), (SMA ₃ −SMA ₂ ),..., (SMA ₁₄ −SMA ₁₃ ) between two consecutive moving average values, (SMA ₃ − − SMA ₂ ), (SMA ₁₂ -SMA ₁₁ ), (SMA ₁₃ -SMA ₁₂ ), and (SMA ₁₄ -SMA ₁₃ ) are within the fourth predetermined range. However, the fourth predetermined range continues only three times. Therefore, in both the example illustrated in FIG. 4 and the example illustrated in FIG. 5, it is determined that the fourth determination condition is not satisfied. As a result, it is possible to prevent the gas appliance that shows the flow rate change pattern as shown in FIGS. 4 and 5 from being determined as a gas appliance that performs the slow ignition operation.

  As described above, according to the embodiment of the present invention, even if it is difficult to extract an intermediate stable flow rate from a flow rate change pattern measured at regular time intervals, a gas appliance that performs a slow ignition operation. The start of operation can be detected. Note that the various determinations described above may be executed after waiting for accumulation of a plurality of flow rate values corresponding to a plurality of measurement timings included in the determination period. Alternatively, the acquisition and determination of the flow rate value or the difference value may be performed in parallel.

(Hardware configuration)
FIG. 6 shows an exemplary hardware configuration of the gas meter 100. In the configuration illustrated in FIG. 6, the gas meter 100 includes a central processing circuit (CPU) 210, a memory 220, a flow meter 204, and a cutoff device 222. The flow meter 204 is an example of the flow measurement unit 104 shown in FIG. 1 and may be a known flow meter, for example, an ultrasonic flow meter. The cutoff device 222 is an example of the cutoff means 122 shown in FIG. 1, and a known cutoff device, for example, a cutoff valve can be used.

  The CPU 210 executes a computer program 221 stored in the memory 220. The computer program 221 describes the various processes described above. For example, the CPU 210 executes various processes of the calculation unit 108, the difference value conversion unit 112, and the appliance determination unit 116 shown in FIG. The memory 220 typically includes RAM and ROM, and corresponds to, for example, the holding unit 106 and the conversion table holding unit 110 shown in FIG. The difference value conversion unit 112 and / or the instrument determination unit 116 may include the memory 220 as a part thereof. It should be noted that the reference value for determining whether to shut off the gas can be stored in the memory 220.

  Each of the calculation means 108, the difference value conversion means 112, and the appliance determination means 116 may be part of a single processor (CPU 210). The control unit 105 may be realized by a set of a plurality of processors. The control means 105 may include one or more memories and peripheral circuits. One or more memories may be arranged outside the control unit 105. For example, the holding unit 106 may be disposed outside the control unit 105. By executing the various processes described above using the CPU 210 and the memory 220, it is possible to determine the appliance with high accuracy.

  The embodiments of the present invention have been described above. The above description of the embodiment is an exemplification of the present invention and does not limit the present invention. In addition, an embodiment in which the components described in the above embodiment are appropriately combined is possible. The present invention can be modified, replaced, added and omitted within the scope of the claims and the equivalents thereof.

  According to the embodiment of the present invention, in the flow rate change pattern, even when a flat portion does not appear in the middle of an increase in the flow rate at the start of operation, the use of the gas appliance that performs the slow ignition operation is started. Can be detected. Embodiments of the present invention are not limited to fan heaters, and can be applied to discrimination of gas appliances (for example, dryers) that can have a flat portion in the middle of an increase in flow rate at the start of operation in a flow rate change pattern. It is useful for a gas meter having a discrimination function of gas appliances.

13 to 15 Gas appliance 100 Gas meter 102 Flow path 104 Flow rate measuring means 105 Control means 106 Holding means 108 Calculation means 110 Conversion table holding means 112 Difference value conversion means 116 Appliance determination means 122 Blocking means

Claims (5)

A flow rate measuring means for measuring the flow rate of gas flowing in the flow path at regular time intervals;
A calculation means for calculating a difference value between flow rate values at two consecutive measurement timings;
Holding means for temporarily holding the flow value and the difference value;
Instrument determination means for determining that the gas instrument that has started operation is a specific gas instrument when a predetermined determination condition is satisfied;
With
In the first predetermined number of difference values from the start of operation of the gas appliance, the appliance determination means includes a first predetermined number of positive difference values within a first predetermined range as a first predetermined number. When the determination condition is satisfied, the flow rate measuring device determines that the gas appliance is the specific gas appliance.   The appliance determination means is configured to calculate, as the predetermined determination condition, an arithmetic average of a third predetermined number of flow values measured after a plurality of flow values used for calculating the first predetermined number of difference values is a second predetermined value. The flow rate measuring device according to claim 1, wherein when the second determination condition within the range is further satisfied, the gas appliance is determined as the specific gas appliance.   The appliance determination means, as the predetermined determination condition, when the third determination condition in which a variation from the arithmetic average in the third predetermined number of flow rate values is within a third predetermined range is further satisfied. The flow measuring device according to claim 2, wherein an instrument is determined to be the specific gas instrument. The appliance determination means obtains a plurality of moving average values from a plurality of flow rate values, and determines the gas appliance as the specific gas appliance when a fourth determination condition is further satisfied as the predetermined determination condition. And
The fourth determination condition is a condition in which a difference between two consecutive moving average values among the plurality of moving average values is continuously within a fourth predetermined range for a first predetermined number of times or more. The flow rate measuring device according to any one of 1 to 3. A conversion table holding means for holding a conversion table in which a plurality of sections according to the size of the difference value and inclinations determined according to the respective sections are associated;
Difference value conversion means for converting the difference value into the slope based on the conversion table;
Further comprising
In the first predetermined number of inclinations corresponding to the first predetermined number of difference values from the start of operation of the gas appliance, the appliance determination means has an inclination within a fifth predetermined range equal to or greater than the second predetermined number. The flow rate measuring device according to claim 1, wherein it is determined whether or not the first determination condition is satisfied by determining whether or not it exists.

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