JP2014215211A - Flow rate measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow rate measurement device capable of acquiring the total flow rate of a fluid passing through even when there is a measurement flow passage where the flow rate of the fluid cannot be measured correctly.SOLUTION: A gas measurement device 1 includes: a plurality of measurement flow passages 22a-22d provided in parallel between a flow inlet 7 where a fluid flows in and a flow outlet 8 where the fluid flows out; individual flow rate measurement units 31a-31d provided at the measurement flow passages 22a-22d respectively and acquiring the flow rate of the fluid passing through the measurement flow passages 22a-22d; individual measurement abnormality detection units 32a-32d for detecting abnormality of the measurement flow passages 22a-22d; a flow rate information unit 33 for calculating the total flow rate by acquiring the flow rate acquired in the individual flow rate measurement units 31a-31d and abnormality information; and a flow rate ratio storage unit 34 for storing flow rate ratio data showing a flow rate ratio between the respective measurement flow passages.

Description

  The present invention relates to a flow meter that measures the flow rate of a fluid such as a gas, and more particularly to a flow rate measuring device that includes a plurality of measurement channels.

  As a flow meter used in a gas meter that measures the amount of gas used, the flow rate of the fluid is detected based on the time (propagation time) that the ultrasonic wave propagates through the fluid, and the detected flow rate is multiplied by the cross-sectional area of the flow path. Ultrasonic flowmeters that measure are well known.

  Conventionally, this type of flow rate measuring apparatus is used in facilities that consume a large amount of gas, such as hospitals and factories, as shown in FIG. 6, such as a transducer drive unit 101, a control circuit unit 102, and a plurality of measurement channels 103 ( 103a to 103c), the transducer 104 (104a, 104b), the safety sensor unit 105, the memory unit 106, the cutoff valve driving unit 107, the cutoff valve 108, and the display unit 109 ( For example, see Patent Document 1).

  Then, the flow rate of each measurement flow path 103 is measured for each of the plurality of measurement flow paths 103 using the transducer 104 provided in the measurement means, and the control circuit unit 102 is measured by each measurement flow path 103. The total flow from the inflow path to the outflow path is obtained by adding the flow rates.

  In addition, when the occurrence of an abnormality in a plurality of measurement channels 103 is detected, a flow rate obtained by multiplying the flow rate in a normal measurement channel in which no abnormality is detected is used instead of the flow rate in the measurement channel in which the abnormality is detected. The flow rate flowing through the measurement channel in which an abnormality has occurred is calculated.

JP 2004-20395 A

  However, although the conventional configuration is based on the premise that the flow rate uniformly flows in the plurality of measurement channels, the flow rate does not flow uniformly in the plurality of measurement channels. An accurate flow rate cannot be calculated by using a flow rate that is equal to the flow rate in a normal measurement channel in which no abnormality is detected in place of the flow rate in FIG. That is, there is a problem that an accurate flow rate cannot be measured if an abnormality such as a failure of a transducer, a deformation of the measurement channel, or a disconnection of a wiring connecting the transducer occurs in any of the measurement channels. .

  The present invention solves the above-mentioned conventional problem, and when a flow rate does not flow uniformly with respect to a plurality of measurement channels, an accurate flow rate even when an abnormality occurs in any of the plurality of measurement channels. It aims at providing the flow measuring device which can measure.

  The flow rate measuring device according to the present invention corresponds to each of the plurality of measurement channels provided in parallel between the inlet into which the fluid flows and the outlet from which the fluid flows out, and the plurality of measurement channels. An individual flow rate measurement unit that measures the individual flow rate of the fluid that is provided, an individual measurement abnormality detection unit that detects a measurement abnormality in the individual flow rate measurement unit, and an output that receives the flow rate from the individual flow rate measurement unit A flow rate information unit for obtaining a sum of the flow rates of the fluid passing through the outlet, and the flow rate information unit is configured in advance so that the flow rate of the fluid passing through the plurality of measurement flow paths when the individual flow rate measurement unit is normal in advance. A flow rate storage unit that stores a flow rate ratio, and when an abnormality is detected by the individual measurement abnormality detection unit, the flow rate of the measurement channel in which the abnormality is detected is set to normal flow rate information of the measurement channel and the flow rate Flow calculated from flow rate ratio It is configured to determine the flow rate sum of the fluid passing through the outlet from the inlet as.

  The present invention has the configuration described above, and has an effect that the total flow rate of the fluid passing through the measurement channel can be obtained even when there is a measurement channel in which the fluid flow rate cannot be measured correctly.

The top view which shows schematically the structure of the gas measuring device in Embodiment 1 of this invention. The figure which shows typically the principal part structure of the gas measuring device in Embodiment 1 of this invention. The block diagram which shows the flow volume information part and individual flow volume measurement part of the gas measuring device in Embodiment 1 of this invention. The graph which shows an example of the relationship between the flow rate ratio data memorize | stored in the flow rate ratio memory | storage part with which the main control part of the gas measuring device in Embodiment 1 of this invention is equipped, and the gas flow rate which passed the measurement flow path. The flowchart which shows an example of the processing flow which concerns on the gas measuring device in Embodiment 1 of this invention. Block diagram showing the configuration of a conventional gas measuring device

  The first invention is a plurality of measurement channels provided in parallel between an inlet into which a fluid flows and an outlet from which the fluid flows out, and a passage provided corresponding to each of the plurality of measurement channels. An individual flow rate measurement unit for measuring the individual flow rate of the fluid to be measured, an individual measurement abnormality detection unit for detecting a measurement abnormality in the individual flow rate measurement unit, and an output of the flow rate from the individual flow rate measurement unit, and the flow rate from the inlet. A flow rate information unit for obtaining a sum of the flow rates of the fluid passing through the outlet, and the flow rate information unit is configured to obtain a flow rate ratio of the fluid passing through the plurality of measurement channels when the individual flow rate measurement unit is normal in advance. A flow rate storage unit for storing, and when an abnormality is detected by the individual measurement abnormality detection unit, the flow rate of the measurement channel in which the abnormality is detected is determined from the flow rate information of the normal measurement channel and the flow rate ratio. As the calculated flow rate, the flow Since the sum of the flow rates of the fluid passing through the outlet from the mouth is obtained, an abnormality occurs in one measurement channel among the plurality of measurement channels, and the fluid passing through the measurement channel Even when the flow rate cannot be obtained, the fluid that passes through the measurement flow channel in which an abnormality has occurred from the flow rate and flow rate ratio of the fluid obtained by the individual flow rate detection unit provided in the other measurement flow channel And the sum of the flow rates of the fluid passing from the inlet to the outlet can be obtained.

  According to a second aspect of the present invention, in the flow measurement device according to the first aspect, when the abnormality is detected by the individual measurement abnormality detection unit, the flow information unit includes flow information on other normal measurement channels. The flow rate of the fluid passing through the measurement flow path in which an abnormality has occurred is estimated from the respective flow rate ratios, and the sum of the flow rates passing through the flow outlet from the flow inlet is determined. Even if an abnormality occurs in, the flow rate of the measurement channel where the abnormality occurred is estimated from the flow rate of other normal measurement channels, and the flow rate value approximated by the true value of the flow rate in the abnormal measurement channel Can be obtained.

  According to a third aspect of the present invention, in the flow measurement device according to the first aspect, the flow rate information unit is one of a plurality of other normal measurement channels when an abnormality is detected by the individual measurement abnormality detection unit. The flow rate information for one normal measurement channel and the flow rate of the fluid passing through the measurement channel in which an abnormality has occurred are estimated from the flow rate ratio, and the sum of the flow rates passing through the outlet from the inlet is determined. Even if an abnormality occurs in a certain measurement channel, if there is at least one normal measurement channel, the flow rate of the abnormal measurement channel is estimated from the flow rate in the normal measurement channel, and the total flow rate of the fluid Can be requested.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following, the same or corresponding components are denoted by the same reference numerals throughout all the drawings, and the description thereof is omitted.
(Embodiment 1)
(Configuration of gas measuring device)
First, the configuration of a gas measuring device (flow rate measuring device) 1 according to Embodiment 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view showing a configuration related to a flow rate measurement process in the gas measurement device 1 of the present embodiment. FIG. 2 is a block diagram showing the main control unit 9 and the auxiliary control unit 6 in the gas measuring device 1 according to the present embodiment.

  The gas measuring device 1 according to the present embodiment is an ultrasonic gas meter that is installed in the middle of a gas pipe and obtains a consumed gas flow rate (gas consumption). The gas measuring device 1 is not limited to such an ultrasonic gas meter. For example, the gas flow rate may be obtained by an instantaneous flow meter such as a flow sensor using an electronic detection principle or a fluidic sensor.

  As shown in FIG. 1, the gas measuring device 1 includes a flow path unit (flow path) 2, upstream ultrasonic sensors 4 a to 4 d, downstream ultrasonic sensors 5 a to 5 d, auxiliary control units 6 a to 6 d, and an inlet 7. , Outlet 8, main control unit 9, battery 10, display unit 11, security sensor 12, and electronic circuit board 30. Here, it is assumed that the gas flows in one direction in the flow path unit 2 from the inlet 7 toward the outlet 8.

  The inlet 7 is an inlet through which gas flows into the gas measuring device 1 from the gas pipe on the gas supply side. In the gas measuring device 1 according to the present embodiment, an inflow port 7 is provided on the upper surface, and the gas pipe on the gas supply side and the flow path unit 2 are connected.

  The outflow port 8 is an outlet through which gas flows from the gas measuring device 1 to the gas pipe on the gas consumption side. In the gas measuring device 1 according to the present embodiment, an outlet 8 is provided on the upper surface, and the gas pipe on the gas consumption side and the flow path unit 2 are connected.

  The flow path unit 2 is a cylindrical tube having a rectangular cross section through which a gas supplied to a consumer flows. As shown in FIG. 1, the flow path unit 2 includes a plurality of measurement flow paths 22a to 22d, upstream ultrasonic sensors 4a to 4d, and downstream ultrasonic sensors 5a to 5d in the measurement flow paths 22a to 22d. It is configured with.

  Here, the measurement flow paths 22a to 22d are flow paths for measuring the flow rate of the consumed gas (the flow rate of the gas passing through the gas measurement device 1). The flow channel cross-sectional areas of the measurement flow channels 22a to 22d may be the same or different. In addition, when it is not necessary to distinguish and explain the measurement flow paths 22a to 22d, they are simply referred to as measurement flow paths 22.

  Further, an inlet buffer 21 is provided on the upstream side of the flow path unit 2, and an outlet buffer 23 is provided on the downstream side. The inlet buffer 21, the flow path unit 2, and the outlet buffer 23 communicate with each other, and the flow rate of the gas passing between the inlet buffer 21 and the outlet buffer 23 is measured by the flow path unit 2.

  Further, the gas measuring device 1 includes a shutoff valve 3 upstream of the flow path unit 2 (upstream of the inlet buffer 21). For example, the shutoff valve 3 is configured so that the flow path unit 2 is detected when an abnormality such as gas leakage is detected between the gas measuring device 1 and the gas device, or in response to a shutoff request for the flow path unit 2 from the outside. The gas flow is blocked and the gas flow is blocked. The shutoff valve 3 can block or open the flow path between the inlet 7 and the inlet buffer 21 based on a control instruction from the main controller 9. The shut-off valve 3 includes a valve body (not shown) for closing the flow path of the flow path unit 2 and a stepping motor (not shown) that is a power source of the valve body. First, the flow path of the flow path unit 2 is closed or opened as follows.

  That is, in the shut-off valve 3, a pulsed current having a phase difference is applied to a stator coil (not shown) of the stepping motor in accordance with a control instruction from the main control unit 9. Then, by applying this current, the rotor (not shown) of the stepping motor rotates forward. Due to the forward rotation of the rotor, the valve element advances toward the valve seat (not shown) and closes the flow path. Thereby, the gas flow can be shut off in the gas measuring device 1. On the contrary, when the flow path is opened, the stepping motor is reversely rotated in the shutoff valve 3 so that the valve body is separated from the valve seat.

  The upstream ultrasonic sensors 4a to 4d and the downstream ultrasonic sensors 5a to 5d transmit and receive ultrasonic waves to each other. The upstream ultrasonic sensors 4a to 4d and the downstream ultrasonic sensors 5a to 5d are provided in the measurement channels 22a to 22d, respectively. Note that the upstream ultrasonic sensors 4a to 4d are simply referred to as the upstream ultrasonic sensor 4 when there is no need to distinguish between them. Similarly, the downstream ultrasonic sensors 5a to 5d are simply referred to as the downstream ultrasonic sensor 5 when it is not necessary to distinguish between them.

  The upstream ultrasonic sensor 4 and the downstream ultrasonic sensor 5 are driven in accordance with control instructions from auxiliary control units 6 a to 6 d provided in association with the respective measurement flow paths 22. It is configured as follows. The auxiliary control units 6a to 6d are also simply referred to as the auxiliary control unit 6 when it is not necessary to distinguish between them.

  That is, the upstream ultrasonic sensor 4 is provided on the upstream side wall in the measurement flow path 22, and the downstream ultrasonic sensor 5 is provided on the downstream side wall in the measurement flow path 22 so as to face each other. When a drive signal (control signal) is input from the main control unit 9 to the upstream ultrasonic sensor 4 via the auxiliary control unit 6, the upstream ultrasonic sensor 4 transmits ultrasonic waves to the downstream ultrasonic sensor 5. Output toward.

  The ultrasonic wave output from the upstream ultrasonic sensor 4 travels obliquely downward in the measurement flow path 22 toward the downstream side and propagates toward the downstream ultrasonic sensor 5. Conversely, when a drive signal is input from the main control unit 9 to the downstream ultrasonic sensor 5 via the auxiliary control unit 6, the downstream ultrasonic sensor 5 directs the ultrasonic wave toward the upstream ultrasonic sensor 4. Output. The ultrasonic wave output from the downstream ultrasonic sensor 5 travels obliquely upward in the measurement channel 22 toward the upstream side and propagates toward the upstream ultrasonic sensor 4.

  Then, the individual flow rate measurement unit 31 in the auxiliary control unit 6 measures the arrival time of each ultrasonic wave, and obtains the flow velocity of the gas flowing through the flow path unit 2 from the difference in arrival time. Then, the individual flow rate measurement unit 31 obtains the flow rate by multiplying the obtained flow velocity by the cross-sectional area of the flow path unit 2 or the like. When the individual flow rate measurement unit 31 obtains the gas flow rate, the individual flow rate measurement unit 31 outputs the obtained result to the flow rate information unit 33 in the main control unit 9, and the flow rate information unit 33 obtains the total gas flow rate flowing through the entire gas measurement device 1.

  The main control unit 9 controls various operations in each unit of the gas measuring device 1. The main control unit 9 determines abnormality of the maximum flow rate over based on the total gas flow rate calculated by the flow rate information unit 33, and detects the abnormality. The presence or absence of an abnormality is determined from the sensing result of the sensor 12 for a sensor, or it is determined whether or not an instruction to shut off a flow path formed in the gas measuring device 1 is received from the outside. When it is determined that an abnormality has occurred, or when it is determined that a shut-off instruction has been received, the main control unit 9 applies a current to the shut-off valve 3 so that the flow path of the flow path unit 2 is set as described above. Control to close.

  Further, the main control unit 9 controls to display various information such as displaying the integrated value of the flow rate based on the total gas flow rate calculated by the flow rate information unit 33 on the display unit 11 constituted by an LCD or the like. Further, the main control unit 9 also includes a flow rate information unit 33 and a flow rate ratio storage unit 34 as “flow rate measurement processing at the time of occurrence of abnormality”, and estimates the flow rate in the flow channel when an abnormality occurs in the measurement flow channel. be able to. Details of the “flow rate measurement process at occurrence of abnormality” in the gas measurement device 1 according to the present embodiment will be described later.

  In addition, the auxiliary control units 6a to 6d include individual measurement abnormality detection units 32a to 32d, respectively, and can also detect an abnormality in the measurement channel.

  The auxiliary control unit 6 described above can be realized by, for example, an ultrasonic measurement LSI (Large Scale Integration). This ultrasonic measurement LSI includes an analog circuit that enables ultrasonic measurement and a digital circuit that sequentially performs an operation of measuring the propagation time of ultrasonic waves. On the other hand, the main control unit 9 can be realized by a CPU, for example.

(Configuration related to flow measurement processing when an abnormality occurs)
Here, in addition to FIG. 1, FIG. 2, the structure which concerns on the "gas flow rate measurement process" in the gas measuring device 1 which concerns on this Embodiment is demonstrated more concretely. FIG. 3 is a diagram illustrating a flow rate information unit and an individual flow rate measurement unit in the flow rate measurement device.

  As shown in FIG. 2, the main control unit 9 includes a flow rate ratio storage unit 34 as a configuration related to the “flow rate measurement process when an abnormality occurs”. In the flow rate ratio storage unit 34, the flow rate ratio between the flow rate in each measurement flow channel and the other measurement flow channel is stored as flow rate ratio data.

  The auxiliary control units 6a to 6d are provided with individual flow rate measurement units 31a to 31d and individual measurement abnormality detection units 32a to 32d. When there is no need to distinguish between them, the individual flow rate measurement unit 31 is simply used. The individual measurement abnormality detection unit 32 will be referred to.

  The individual flow rate measuring unit 31 obtains the flow velocity of the gas per unit time flowing through the measurement flow path 22 from the difference in the arrival time of the ultrasonic waves obtained by the upstream ultrasonic sensor 4 and the downstream ultrasonic sensor 5, Based on the obtained flow velocity and the cross-sectional area of the measurement flow path 22, the flow rate of the gas flowing through the measurement flow path 22 is obtained. And it outputs to the flow volume information part 33 in the main control part 9. The upstream ultrasonic sensor 4, the downstream ultrasonic sensor 5, and the individual flow rate measuring unit 31 realize the flow rate measuring means of the present invention.

  In the present embodiment, the upstream ultrasonic sensor 4 and the downstream ultrasonic sensor 5 are configured to transmit and receive ultrasonic waves a plurality of times every 2 seconds. For this reason, in the gas measuring device 1 which concerns on this Embodiment, it becomes the structure which confirms the flow volume change of gas every 2 second.

  The individual measurement abnormality detection unit 32 is configured to monitor an abnormality in the measurement flow path every time a change in gas flow rate is confirmed. For this reason, in the gas measuring device 1 which concerns on this Embodiment, it becomes the structure which monitors the abnormality of a measurement flow path every 2 seconds.

  The flow rate information unit 33 receives the flow rate information and abnormality detection information of the measurement flow path from the individual flow rate measurement unit 31 and obtains the sum of the flow rates. Further, when the abnormality detection information is received, the flow rate ratio data stored in the flow rate ratio storage unit 34 is referred to and the flow rate in the measurement channel is estimated from the flow rate measured in another normal measurement channel. Calculate the total flow rate.

  The flow rate ratio storage unit 34 is a readable / writable storage device that stores information such as flow rate ratio data used when the flow rate information unit 33 calculates the sum of the flow rates. For example, the flow rate ratio storage unit 34 can be realized by a semiconductor storage device such as a readable / writable RAM or ROM.

  The flow rate ratio storage unit 34 stores the flow rate ratio of the measurement flow path 22 with respect to the other measurement flow paths 22 from the flow rate of the gas flowing through each measurement flow path 22 per unit time.

  Specifically, as shown in FIG. 4, the flow rate ratio storage unit 34 stores a flow rate ratio that is determined according to the gas flow rate flowing through the measurement flow paths 22 a to 22 d. That is, the ratio of the flow rate of one measurement flow channel to the flow rate of one or more other measurement flow channels is determined as the flow rate ratio data in a state where the gas flow rate flowing through each measurement flow channel 22a to 22d is known in advance. It is stored in the ratio storage unit 34. The flow rate ratio data recorded as these flow rate ratio storage units 34 are values that change in accordance with fluctuations in the gas flow rates (Qa to Qd) flowing through the measurement flow paths 22a to 22d.

  However, the flow rate data is not limited to this. For example, the flow rate ratio data may be a fixed value that is constant regardless of the magnitude of the gas flow rate flowing through the measurement flow paths 22a to 22d.

  The flow rate information unit 33 estimates the flow rate of the abnormal measurement channel by referring to the flow rate measured in the normal measurement channel and the flow rate storage unit 34 recorded as the flow rate data. The total flow rate of the gas flowing through the flow path 22 is calculated.

  Next, a process flow of “gas flow measurement process” for obtaining the total flow rate of the gas flowing through the gas measurement apparatus 1 in the gas measurement apparatus 1 having the above-described configuration will be described with reference to FIG. FIG. 5 is a flowchart showing an example of a processing flow related to the gas measuring device 1 according to the present embodiment.

(Flow rate measurement processing method when an abnormality occurs)
First, the flow rate ratio data is stored in the flow rate ratio storage unit 34 as pre-processing (step S11).

  More specifically, when the measurement channel 22 is normal in advance, a gas whose gas flow rate is known in advance is caused to flow from the inlet 7, and the flow rate (Qa) measured in each of the measurement channels 22a to 22d at this time. To record Qd). Then, the measured flow rates are compared, and the ratio of the flow rates flowing through the flow paths is calculated. The flow rate through which this operation is passed is changed a plurality of times, and the ratio of the flow rate flowing through each flow path is stored in the flow rate ratio storage unit 34.

  In the above embodiment, the flow rate ratio data of the measurement flow paths 22a to 22d is described as having individual characteristics in the flow rate range as shown in FIG. 4, but the flow rate ratios of the measurement flow paths 22a to 22d are described. Needless to say, when the data is represented by a straight line having the same slope, it is not necessary to change the flow rate a plurality of times, and it is possible to do it once.

  After performing the above-described pretreatment, the gas measuring device 1 is installed for actual use. And use of gas is started by the gas equipment etc. which are connected with the gas measuring device 1. At this time, the shutoff valve 3 is assumed to open the flow path of the flow path unit 2.

  When the use of the gas is started, the gas that has entered from the inlet 7 is divided into the measurement flow paths 22 a to 22 d through the inlet buffer 21 and flows toward the outlet buffer 23. In each individual flow measurement part 31a-31d, from the difference in the arrival time of the ultrasonic wave measured by the upstream ultrasonic sensors 4a-4d and the downstream ultrasonic sensors 5a-5d, the gas flowing through the measurement flow paths 22a-22d Determine the flow rate. And from each calculated | required flow velocity, the flow volume of each gas in each measurement flow path 22a-22d is calculated (step S12).

  Further, each individual flow rate measurement unit 31 acquires abnormality detection information indicating whether or not there is an abnormality in each measurement channel from each individual measurement abnormality detection unit 32 (step S13).

  Thereafter, each individual flow rate measurement unit 31 outputs flow rate information and abnormality detection information in the measurement channel to the flow rate information unit 33 (step S14).

  Next, in the flow rate information unit 33, it is determined whether there is a measurement channel in which an abnormality is detected (step S15). If it is determined that there is an abnormality, the flow rate ratio data is read from the flow rate ratio storage unit 34, and the flow rate of the abnormal measurement flow path is estimated using the flow rate ratio data and the flow rates in the other measurement flow paths (step S16). For example, when the measurement flow path 22a is abnormal, the ratio between the flow rate (Qa) of the measurement flow path 22a and the flow rates (Qb to Qd) of the other measurement flow paths 22b to 22d is calculated from the flow rate ratio storage unit 34. The flow rate ratio data to be expressed is read, and the flow rate (Qa) of the abnormal measurement channel is estimated using the flow rates (Qb to Qd) in the other measurement channels. Three types of flow rates can be estimated using other measurement channels, and the average value of these is calculated, and the flow rate (Qa) of the abnormal measurement channel is estimated. If it is determined in step S15 that there is no abnormality, the process in step S16 is omitted.

  When estimating the flow rate in step S16, in addition to the method of estimating from the average value using other measurement channels as described above, abnormal measurement is performed using flow rate information of one normal measurement flow rate. A method for estimating the flow rate of the flow path is also conceivable.

  And the sum total of the flow volume of each measurement flow path calculated | required by the above is calculated, and the result is determined to be the actual total flow volume of the gas which flowed through the gas measuring device 1 (step S17).

(effect)
As described above, the total gas total flow rate flowing through the gas measuring device 1 can be obtained from the gas flow rate obtained for each of the measurement flow paths 22a to 22d.

  By the way, in use of the gas measuring device 1, an abnormality occurs in any of the upstream ultrasonic sensors 4a to 4d, the downstream ultrasonic sensors 5a to 5d, and the auxiliary control units 6a to 6d provided in the measurement flow paths 22a to 22d. May occur, and the flow rate of the gas flowing through the measurement flow paths 22a to 22d may not be measured correctly.

  As a countermeasure method when an abnormality occurs, as described in the conventional example, the individual flow rate measurement units 31a to 31d estimate the flow rate measured in the normal measurement flow path and the same flow rate as the flow rate in the abnormal measurement flow path. Although the structure which performs is considered, this assumes that the flow volume which flows into each measurement flow path is the same. However, in practice, even if the cross-sectional areas of the measurement flow paths 22a to 22d are the same, it is difficult to equalize the flow state from the inlet 7 to each measurement flow path. The flow rate cannot be made the same, and the total gas total flow rate flowing through the gas measuring device 1 cannot be obtained.

  On the other hand, in the gas measuring device 1 according to the present embodiment, as described above, the auxiliary control units 6a to 6d obtain the respective flow rates in the measurement flow paths 22a to 22d, respectively, and an abnormality is detected. Since the main control unit 9 can estimate the abnormal flow rate of the measurement flow path 22, it can correctly measure the flow rate obtained in the other measurement flow paths 22 except the measurement flow path 22 where the gas flow rate cannot be measured correctly. The flow rate of the measurement flow path 22 that has not been present can be estimated, and the total gas total flow rate that flows through the gas measurement device 1 can be obtained.

  That is, even if the flow rates flowing through the measurement flow paths 22a to 22d are not the same, the flow rate ratio data between the measurement flow paths obtained in advance at the normal time is used to obtain an abnormality based on the flow rate of the normal measurement flow paths. It is possible to determine the flow rate of the measurement flow path in which the occurrence of spilling occurs.

  Further, in the gas measurement device 1 according to the present embodiment, a gas whose total flow rate is known in advance is caused to flow from the inlet 7 of the gas measurement device 1 and measured at each of the measurement flow paths 22a to 22d at this time. In this configuration, the flow rate ratio data indicating the flow rate ratio with each measurement channel 22 is calculated from the flow rates (Qa to Qd). That is, once a gas whose total flow rate is known is caused to flow, flow rate ratio data used in the flow rate information unit 33 provided in the main control unit 9 can be obtained collectively.

(Modification)
In addition, in the gas measurement device 1 according to the present embodiment, the configuration includes four measurement flow paths 22, but is not limited thereto, and may be configured to include two or three, for example. It may be a configuration provided with five or more, and it is preferable that the number of the measurement flow paths 22 is appropriately determined in consideration of the size of the gas flow rate used.

  Further, in the gas measurement device 1 according to the present embodiment, in the measurement flow path 22 in which an abnormality has occurred, the flow rate ratio data from the flow rate storage unit 34 is used to calculate the average from the flow rates of other normal measurement flow paths 22. Although it is the structure which takes a value and estimates the flow volume of the measurement flow path where abnormality occurred, it is not limited to this structure.

  For example, the measurement flow path 22 in which the abnormality has occurred is configured to estimate the gas flow rate in the measurement flow path in which the abnormality has occurred from the flow rate ratio data of one normal measurement flow path 22 among the plurality of normal measurement flow paths 22. It may be.

  Further, the gas flow rate of the measurement flow path in which an abnormality has occurred is estimated from the flow rate and flow rate ratio data measured in each of the plurality of normal measurement flow paths 22, and the maximum value and the minimum value of the multiple estimated flow rates are respectively determined. It is good also as a structure which determines the flow rate of the gas in the measurement flow path in which abnormality generate | occur | produces the average value of the value except for. Or it is good also as a structure which calculates | requires an average value except the estimated flow volume from which a value becomes larger than a predetermined value compared with another estimated flow volume, or becomes small, and determines with an actual flow volume. Alternatively, the measurement flow path 22 in which the abnormality has occurred is obtained by calculating the median or mode value of the estimated flow rate of the gas in the abnormal measurement flow path obtained from the flow rate ratio data with the normal measurement flow path 22. The structure which determines with may be sufficient. It is preferable that the flow rate information unit 33 determine the actual gas flow rate by adopting a method capable of obtaining an approximate value that approximates the true value from the actually obtained estimated flow rate distribution.

  In the above-described embodiment, the gas measuring device 1 that measures the amount of gas used has been described as an example. However, the measurement target is not limited to gas, and may be a fluid.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  The flow rate measuring device of the present invention is provided with a plurality of flow paths for measuring the flow rate of a large-capacity gas, and the flow rate measuring apparatus for measuring the total flow rate of the fluid from the flow rate of the fluid passing through each of the multiple flow paths. It is particularly useful.

1 Gas measuring device (flow rate measuring device)
7 Inlet 8 Outlet 22, 22a-22d Measurement flow path 31, 31a-31d Individual flow rate measurement unit 32, 32a-32d Individual measurement abnormality detection unit 33 Flow rate information unit 34 Flow rate ratio storage unit

Claims (3)

A plurality of measurement channels provided in parallel between an inlet through which the fluid flows and an outlet through which the fluid flows;
An individual flow rate measuring unit that measures the individual flow rate of the fluid that is provided corresponding to each of the plurality of measurement flow paths;
An individual measurement abnormality detection unit for detecting a measurement abnormality in the individual flow rate measurement unit;
A flow rate information unit that receives the output of the flow rate from the individual flow rate measurement unit and obtains the sum of the flow rates of the fluid that passes through the outlet port from the inlet port,
The flow rate information unit has a flow rate ratio storage unit that stores a flow rate ratio of the fluid that passes through the plurality of measurement channels when the individual flow rate measurement unit is normal in advance, and the individual measurement abnormality detection unit When an abnormality is detected, the flow rate of the fluid passing through the outlet from the inlet is set as the flow rate calculated from the flow rate information of the normal measurement channel and the flow rate ratio. A flow rate measuring device characterized by obtaining the sum. When an abnormality is detected by the individual measurement abnormality detection unit, the flow rate information unit passes through the measurement channel in which an abnormality has occurred from the flow rate information for the other plurality of normal measurement channels and the respective flow rate ratios. The flow rate measuring device according to claim 1, wherein the flow rate of the fluid to be estimated is estimated and a sum of the flow rates passing through the outlet port from the inlet port is obtained. When an abnormality is detected by the individual measurement abnormality detection unit, the flow rate information unit is abnormal from the flow rate information for one normal measurement channel among a plurality of other normal measurement channels and the flow rate ratio. The flow rate measuring device according to claim 1, wherein the flow rate of the fluid passing through the measurement flow path in which the occurrence of the flow is estimated and the sum total of the flow rates passing through the outlet port is obtained from the inlet port.

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