JP5974280B2 - Large flow rate measuring device - Google Patents

Description

  The present invention relates to a large flow rate measuring apparatus for measuring a flow rate of a fluid to be measured such as gas, particularly a large flow rate.

  In general, a measurement device that measures the flow rate of a fluid to be measured such as gas measures the flow rate based on an output from a flow sensor. As this flow sensor, an ultrasonic sensor that performs measurement by transmitting and receiving ultrasonic waves is well known. This measuring device using ultrasonic waves has various advantages, such as being able to perform instantaneous measurement, and is beginning to spread in place of conventional diaphragm membrane type measuring devices in fluids to be measured such as gas.

  However, since the measuring device using ultrasonic waves has a characteristic that the ultrasonic waves are easily attenuated, the measurement flow path for transmitting and receiving the ultrasonic waves cannot be made very large, and a large flow rate measurement that requires a large flow path is required. It was not suitable for the device. That is, when the installation distance between the first and second ultrasonic transducers is increased in a pipe having a diameter larger than that of the ultrasonic transducer, such as plant piping, the S / N ratio decreases. As a result, the measurement accuracy is lowered, and there is a limit to the installation distance between the first and second ultrasonic transducers. Therefore, since the first and second ultrasonic transducers are provided on the side walls of the flow path, the flow path must have a predetermined size (cross section) or less.

  In addition, if the cross-sectional area of the flow path is large, the flow velocity distribution of the fluid to be measured differs greatly between the vicinity of the road wall and the central part due to the viscous resistance of the fluid on the road wall flowing through the flow path. Even in the case of using a sensor, the measurement accuracy deteriorates depending on the position where the flow sensor is provided. From this point of view, not only ultrasonic measurement but also other flow sensors can be used. There was a problem with the direct measurement.

  In order to deal with such a problem, as shown in FIG. 6A, a plurality of branch passages 104 divide between the inlet 102 and the outlet 103 of the flow path 101, and each of the branch passages 104 is branched. A pair of ultrasonic transducers 105 is provided, the flow rate flowing through the branch passage 104 is measured by the propagation time of the ultrasonic wave, and these are added together so that a large flow rate can be measured. That is, as shown in FIG. 5B, the ultrasonic propagation times t11 to t13 and t21 to t23 of the ultrasonic transducers 105 provided in the respective branch passages 104 are summed to calculate the flow rate based on the sum of the propagation times. However, a large flow rate can be measured with ultrasonic waves (see, for example, Patent Document 1).

  In addition, as shown in FIG. 7A, the applicant forms a plurality of branch passages 104 between the inlet 102 and the outlet 103 of the flow path 101 through which a large flow rate flows, as shown in FIG. Measuring means 106 using an ultrasonic transducer is installed in each branch passage 104, the flow rate of the branch passage 104 is measured by the propagation time of the ultrasonic wave to calculate the flow rate, and the calculated flow rate of each branch passage is the flow rate. A method has been proposed in which a large flow rate flowing through the flow path 101 can be measured with ultrasonic waves by summing with the measurement control device 107 (see, for example, Patent Document 1). In the figure, reference numeral 108 denotes an open / close valve provided in each branch passage 104.

Furthermore, since this measuring device has a measuring circuit unit in which the measuring means 106 of each branch passage 104 transmits and receives an ultrasonic wave and calculates the flow rate from the propagation time, the configuration is complicated and the power consumption is increased. As one embodiment, as shown in FIG. 2B, the measurement means 106 is switched by the switching means 109 and switched to the main measurement circuit unit 110 in the flow rate measurement control device 107. By connecting and calculating the flow rate, it is possible to eliminate the individual measurement circuit units inherent to each measurement means 106 and to measure the flow rate of each branch passage with one main measurement circuit unit 110, thereby simplifying the system. I also proposed that.

JP-A-11-287686 Japanese Patent No. 4688253

  Any of the above measurement devices can measure the large flow rate by overcoming the problem of the flow velocity distribution that occurs even if the weakness of ultrasonic measurement and other flow rate sensors are used. Since the flow rate flowing through each branch passage 104 is simply summed to measure a large flow rate, if a measurement error or the like occurs in any one of the branch passages for some reason, the influence of the measurement error is affected by the flow path 101. There was a problem that it appeared directly in the measured flow value of the total flow that flows through the, and lowered the measurement accuracy.

  In the latter measuring device, each measuring unit 106 is switched and connected to one main measuring circuit unit 110 in the flow rate measuring control unit 107 by the switching unit 109 so as to calculate the flow rate of each branch passage. Although the configuration can be simplified, there is no description of the specific configuration, and the measurement circuit unit provided in each measurement means 106 can be simply abolished.

  In addition, since both the measuring devices are configured to measure a large flow rate by summing the flow rates flowing through the respective branch passages 104 as described above, a failure or the like occurs in the measurement means of any one of the branch passages 104. When this occurs, there is also a problem that the flow rate cannot be measured.

  The present invention has been made in view of the above points, and a first object of the present invention is to provide a large flow rate measuring device capable of measuring with high accuracy while simplifying the configuration and saving power. A second object is to enable accurate flow rate measurement to be continued even when an abnormality such as a failure occurs in any of the ultrasonic transducers.

  In order to achieve the first object, the present invention provides a flow path through which a fluid to be measured flows, a plurality of branch passages provided between an inlet and an outlet of the flow path, and each of the plurality of branch paths. A large flow rate measurement apparatus comprising: a measurement unit arranged; and a control unit having a flow rate measurement circuit unit that controls the measurement unit to measure a flow rate of the branch passage. A switching unit for arbitrarily switching and connecting the unit to the flow rate measurement circuit unit; and the flow rate measurement circuit unit calculates an individual flow rate of each branch passage connected via the switching unit, and the individual flow rate is calculated. The total flow rate that flows through the flow path is calculated by calculating and averaging the individual total flow rates that flow through the flow path for each branch passage.

  This makes it possible to accurately measure a large flow rate regardless of factors such as attenuation of ultrasonic waves and variations in flow velocity distribution used for flow rate measurement, as well as measurement and calculation in individual branch passages. Even if there is an error in the individual total flow rate Qm, the error is reduced by averaging the individual total flow rate Qm, and highly accurate measurement is possible.

  In addition, since the individual flow rate of each branch passage is measured and calculated by a single flow rate measurement circuit provided in the control means, as in the case where each branch passage has a measurement circuit made up of arithmetic means, etc. Measurement errors due to performance variations unique to each measurement circuit can also be eliminated, and measurement with higher accuracy becomes possible.

  In addition, since only one flow measurement circuit unit is required, it is possible to measure the simplification of the configuration and power saving, and this large flow measurement device is a unit component (such as an ultrasonic transducer) of a small flow measurement device used for home use. Each branch passage unit component in which a flow sensor is set can be used, and any flow rate measuring device can be easily and easily handled.

  The large flow rate measuring device of the present invention can measure with high accuracy while simplifying the configuration and saving power, and can easily and easily correspond to any size measuring device. A large flow rate measuring device capable of being provided can be provided.

Block diagram of a large flow rate measuring apparatus according to Embodiment 1 of the present invention The block diagram which shows the relationship between the control means and measurement unit of the large flow volume measuring device in Embodiment 1 The flowchart which shows measurement operation | movement of the large flow volume measuring apparatus in the same Embodiment 1. The block diagram which shows the relationship between the control means and measurement unit of the large flow volume measuring apparatus in Embodiment 2 of this invention. The flowchart which shows the measurement operation | movement of the large flow volume measuring apparatus in Embodiment 2 (A) Block diagram showing a conventional large flow rate measuring device, (b) Explanatory drawing showing the same measurement technique (A) Block diagram showing another conventional large flow rate measuring device, (b) Block diagram showing an example of the same measurement

  A first invention is a flow path through which a fluid to be measured flows, a plurality of branch passages provided between an inlet and an outlet of the flow path, a measurement unit disposed in each of the plurality of branch paths, and the measurement And a control means having a flow rate measurement circuit unit for controlling the unit to measure the flow rate of the branch passage, and further comprising a measurement unit for each branch passage in the flow rate measurement circuit unit. Switching means for arbitrarily switching connection is provided, and the flow rate measurement circuit unit calculates an individual flow rate of each branch passage connected via the switching means, and individually flows into the flow path based on the individual flow rate The total flow rate is calculated for each branch passage and averaged to calculate the total flow rate flowing through the flow path.

  This makes it possible to accurately measure a large flow rate regardless of factors such as attenuation of ultrasonic waves and variations in flow velocity distribution used for flow rate measurement, as well as measurement and calculation in individual branch passages. Even if there is an error in the individual total flow rate Qm, the error is reduced by averaging the individual total flow rate Qm, and highly accurate measurement is possible.

  In addition, since the individual flow rate of each branch passage is measured and calculated by a single flow rate measurement circuit provided in the control means, as in the case where each branch passage has a measurement circuit made up of arithmetic means, etc. Measurement errors due to performance variations unique to each measurement circuit can also be eliminated, and measurement with higher accuracy becomes possible.

  In addition, since only one flow measurement circuit unit is required, it is possible to measure the simplification of the configuration and power saving, and this large flow measurement device is a unit component (such as an ultrasonic transducer) of a small flow measurement device used for home use. Each branch passage unit component in which a flow sensor is set can be used, and any flow rate measuring device can be easily and easily handled.

According to a second invention, in the first invention, the measurement unit has a configuration for detecting a flow rate based on a propagation time difference using an ultrasonic transducer disposed in each branch passage,
The flow rate measuring circuit section, the flow rate measuring characteristic of the correction constant by ultrasonic transducers comprise in each branch passage, calculates the individual flow by selectively using the correction constant with the switching by the switching Rikae means As a configuration.

  As a result, since the flow rate of each branch passage is measured using a correction constant suitable for the branch passage, the flow can be reduced while simplifying the configuration and reducing the power consumption including the storage means for storing the correction constant. The total flow rate measurement of the entire road can be made more accurate.

  According to a third invention, in the first and second inventions, the control means includes a plurality of the flow rate measurement circuit units, and the switching means includes the plurality of flow rate measurement units in the branch passages. It is configured to be switchable and connectable to any of the measurement circuit units.

  As a result, maintenance of the flow measurement circuit unit that is not used for measurement among the plurality of flow measurement circuit units can be performed while continuing the flow measurement using the other flow measurement circuit unit. improves.

  According to a fourth aspect, in the third aspect, the apparatus further comprises abnormality detection means for detecting an abnormality of the flow rate measurement circuit unit, and when the abnormality of the flow rate measurement circuit part is detected, the switching means detects the flow rate at which the abnormality is detected. The measurement unit of each branch passage is switched and connected to the flow rate measurement circuit unit other than the measurement circuit unit.

  As a result, even if a fault or abnormality occurs in one of the flow measurement circuit units, it can be connected to another flow measurement circuit unit and measurement can be continued. Will improve.

  According to a fifth aspect of the present invention, in order to achieve the second object, in the fourth aspect of the invention, the abnormality detection means detects a measurement abnormality by the measurement unit of each branch passage, and the abnormality detection means When it is detected that the measurement by any one of the measurement units in the passage is abnormal, the control means resets the measurement of the branch passage, and the flow measurement circuit unit is measured in a branch passage other than the branch passage. The total flow rate flowing in the flow path is calculated based on the individual total flow rate calculated with the individual flow rate.

  This enables high-precision measurement without being affected by the measured flow rate of the branch passage where a failure or abnormality has occurred, and continues to measure the flow rate of the entire flow path even if a failure or abnormality occurs in the measurement of each branch passage. This can greatly improve the reliability of the measuring device.

According to a sixth invention, in the fourth or fifth invention, the control means further includes a communication means, and communicates a failure of the flow measurement circuit unit to the outside.

  As a result, if a failure or abnormality occurs in one of the flow measurement circuit units, it can be communicated to an external management company by means of communication, and measurement is continued using a flow measurement circuit unit other than the failure or abnormality. In addition, since the flow circuit unit that has failed or malfunctioned can be replaced or repaired, the fail-safe property can be recovered at an early stage, and the reliability of the measuring device can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the flow rate sensor using an ultrasonic transducer is described as an example. However, the present invention is not limited to this.

(Embodiment 1)
FIG. 1 is a block diagram of a large flow rate measuring device, FIG. 2 is a block diagram showing the relationship between the control means and a measuring unit provided in each branch passage, and FIG. 3 is a flowchart showing a measuring operation.

  In FIG. 1, reference numeral 1 denotes a flow path through which a large flow rate flows, and a branch passage 4 that is branched into a plurality of portions is provided between the inlet 2 and the outlet 3. Each of the branch passages 4 is provided with a measuring unit 5 described later. 6 is an opening / closing means provided at the inlet 2 of the flow path 1, 7 is a control means for calculating the flow rate flowing through each branch passage 4 and the total flow rate flowing through the entire flow path 1 from this individual flow rate, and 8 is each branch. Switching means 9 for arbitrarily switching and connecting an ultrasonic transducer of the measuring unit 5 to be described later in the passage 4 and the control means 7, 9 is a communication means for communicating with an external management company via the Internet network or the like.

  FIG. 2 shows the relationship between the control means 7 and the measurement unit 5 provided in each branch passage 4, and the first vibrator 10 that transmits ultrasonic waves as a flow sensor to the measurement unit 5 in each branch passage 4. The second vibrator 11 for receiving is arranged in the flow direction. Further, the control means 7 has a flow rate measuring circuit section 12 for calculating an individual flow rate flowing through each branch passage 4 and an individual total flow rate flowing through the entire flow path 1 from the individual flow rate. The total flow rate flowing through the flow path 1 is calculated by averaging the individual total flow rates.

  Reference numeral 13 denotes transmission means for the first vibrator 10, reference numeral 14 denotes reception means for the signal received by the second vibrator 11, and reference numeral 15 denotes amplification means for amplifying the signal from the reception means 14. The amplified signal is a reference signal. When the comparison circuit compares and detects a signal equal to or higher than the reference signal, the ultrasonic signal is repeatedly transmitted after the signal is delayed by the repeating means and the delay means for the set number of times. The propagation time when the transmission of ultrasonic waves is repeated for the set number of times and is completed is obtained by the time measuring means 16 such as a timer counter.

  Next, the transmission / reception of the first vibrator 10 and the second vibrator 11 is switched by the switching means 8, and ultrasonic waves are transmitted from the second vibrator 11 to the first vibrator 10, that is, from downstream to upstream. The transmission is repeated as described above and the propagation time is measured. From the time difference, the flow rate calculation means 18 obtains the flow rate value in consideration of correction specific to the branch passage such as the size of the flow path and the flow state.

  In other words, the flow rate calculation means 18 determines the individual flow rate by using the correction constant specific to the measurement in the measurement unit 5 of each branch passage 4 obtained in advance by experiment for each measurement unit 5.

  Here, in this embodiment, the control means 7 is provided with a plurality of flow rate measurement circuit sections 12 having the same configuration as the flow rate measurement circuit section 12, for example, another one in this embodiment, and the switching means 8 Is configured so that the switching connection destination of each measurement unit 5 can be switched to another flow measurement circuit unit 12.

  Further, the control means 7 is provided with an abnormality detection means 19, and this abnormality detection means 19 detects a failure or abnormality of each flow rate measurement circuit section 12. When the abnormality detecting means 19 detects an abnormality in the flow measurement circuit section 12 that is the connection switching target of each measurement unit 5, the switching means 8 is the flow measurement circuit section 12 that is the switching connection target of each measurement unit 5. Is switched to another normal flow rate measurement circuit unit 12.

  Next, the operation and action will be described with reference to FIG.

In the following description, the number of measurement units 5 is n, the individual flow rate flowing through each branch passage 4 is qm (m = 1 to n), and the individual total flow rate calculated from the individual flow rate qm is Qm (m = 1). To n).

  First, when the control means 7 opens the opening / closing means 6, a fluid to be measured such as gas flows into the flow path 1 from the inlet 2, flows out of the outlet 3 through each branch passage 4, and the flow rate is measured. The

  That is, first, the switching means 8 connects one of the first and second vibrators 10 and 11 of the measuring units 5 provided in each branch passage 4 to the control means 7 (step 31). The flow rate qm is calculated (step 32), and the individual total flow rate Qm flowing through the flow path 1 is calculated from the individual flow rate qm (step 33). When this measurement is completed, the switching means 8 switches and connects the first and second vibrators 10 and 11 of the measurement unit 5 provided in the next branch passage 4 to the control means 7 and measures the individual flow rate qm of the branch passage 4. Then, the individual total flow rate Qm is calculated in the same manner as described above. This is repeated sequentially for the number of branch passages 4 (step 34), and the total flow rate Q of the entire flow path 1 is measured (step 35).

  In the flow rate measurement, first, an ultrasonic wave is transmitted from the first vibrator 10 based on a signal from the transmission means 13, and this ultrasonic signal propagates through the flow of the fluid to be measured and passes through the second vibrator 11. Received by the receiving means 14 and signal processed by the amplifying means 15, the propagation time from transmission to reception is measured by the time measuring means 16.

If the sound in the stationary fluid is c and the flow velocity of the fluid is v, the propagation speed of the ultrasonic wave in the forward direction of the flow is (c + v). When the distance between the first transducer 10 and the second transducer 11 is L, and the angle between the ultrasonic propagation axis and the central axis of the pipe is φ, the time t when the ultrasonic wave reaches is
t = L / (c + vCOSφ) (1)
It becomes.

  The flow rate calculation means 18 calculates the flow rate from the equation (1) based on the time measured by the time measuring means 16 and calculates the individual flow rate q flowing through each branch passage 4 (step 32).

That is, from equation (1), the flow velocity v is
v = (L / tc) / COSφ (2)
If L and φ are known, the flow velocity v can be obtained by measuring t. The individual flow rate qm flowing through each branch passage 4 from this flow velocity v is defined as vm as the flow velocity in each branch passage, Sm as the passage area, and Km as a correction constant specific to the branch passage measurement.
qm = Km · Sm · vm (3)
It becomes.

  Here, after calculating the individual flow rate qm, the flow rate measurement circuit unit 12 first calculates the individual total flow rate Qm flowing through the entire flow path 1 individually for each branch passage 4 (step 33).

  That is, a ratio (total flow rate / individual flow rate) between the total flow rate passing through the outlet 3 of the flow path 1 and the individual flow rate measured in the branch path 4 is obtained in advance for each branch passage 4. The individual total flow rate Qm is obtained for each branch passage from the equation (3) using the ratio (Cm (m = 1 to n)).

That is, the individual total flow rate Qm is calculated from the equation (3).
Qm = Km / Sm / vm / Cm (4)
It becomes.

  It is checked whether the calculation of each individual total flow rate Qm has been performed in all the branch passages 4 (step 34), and the calculation of the individual total flow rate Qm in all the branch passages 4 is finished.

Next, the flow rate calculation means 18 of the control means 7 adds up all the individual total flow rates Q1... Qn calculated for each of the branch passages 4, and divides the sum by the number of branch passages n to give a total flow rate Q. Is calculated (step 35).
Q = (Q1 + Q2 + ... Qn) / n (5)
At that time, the abnormality detection means 19 performs abnormality determination (step 36) of the flow rate measurement circuit unit 12 for switching and connecting the measurement units 5 of each branch passage 4, and if there is an abnormality, the connection destination of the measurement unit 5 of each branch passage 4 Is switched to another flow rate measurement circuit unit 12 (step 37), and the flow rate measurement circuit unit 12 is used to perform the above-described measurement.

  As described above, in this large flow rate measuring device, first, the individual flow rate qm is measured for each branch passage 4, the individual total flow rate Qm is calculated individually, and further, this individual total flow rate Qm is summed. By dividing by the number n and averaging, the final total flow rate Q flowing through the flow path 1 is calculated, so even if the individual total flow rate Qm measured and calculated in each branch passage 4 varies, The variation is reduced by dividing by the number of branch passages n and is averaged. The individual flow qm measured in each branch passage 4 is directly added, or the ultrasonic propagation time of each branch passage 4 is added. Thus, unlike the case of calculating the flow rate, the measurement error values in the respective branch passages 4 are not added as they are, and the measurement accuracy is high.

  In the above measurement, the switching unit 8 switches and connects each branch passage 4 to the flow rate measurement circuit unit 12 of the control unit 7, and the individual flow rate qm, Since the individual total flow rate Qm and the total flow rate Q are calculated, measurement errors due to performance variations unique to each measurement circuit as in the case where each branch passage 4 has a measurement circuit made up of arithmetic means and the like are also eliminated. And more accurate measurement is possible.

  In addition, when the individual flow rate qm is calculated, the flow rate measurement circuit unit 12 calculates the individual flow rate qm by properly using the correction constant specific to each branch passage in accordance with the switching by the switching means 8, so that the individual flow rate qm can be measured with high accuracy. The total flow rate can be measured with higher accuracy.

  In addition, as apparent from the description of the above configuration, it is not necessary to provide a measurement circuit in the measurement unit 5 of each branch passage 4, and it is not necessary to provide a storage unit for storing a correction constant unique to each branch passage. In addition to simplification, it is possible to save power because no power is used in the measurement circuit provided in each branch passage.

  Further, in this large flow rate measuring device, when a failure or abnormality occurs in the flow rate measurement circuit unit 12 that is connected to each measurement unit 5 and performs flow rate measurement, the switching means 8 causes the other flow rate measurement circuit unit 12 to switch. It is possible to continue to measure the flow rate by switching the measurement units 5 to connect to each other. That is, the fail-safe property of the flow rate measurement can be ensured, and the reliability of the measuring device is greatly improved.

  Further, even if there is no abnormality, the switching means 8 can arbitrarily switch the flow measurement circuit unit 12 used for flow measurement, and even if there is no abnormality in the flow measurement circuit unit 12, the flow measurement can be performed by the user's will. Maintenance of the flow rate measurement circuit unit 12 that is not used for flow rate measurement by switching the circuit unit 12 can be performed, for example, check and correction of correction constants can be performed, and maintainability is also improved.

  Further, since the communication means 9 is provided in the control means 7, when a failure occurs in the flow measurement circuit section 12 and the switching means 8 is switched and connected to the normal flow measurement circuit section 12, this is connected to the outside. For example, on a holiday such as Sunday when a large flow rate measuring device is not used, repairs such as replacement of the flow rate measuring circuit unit 12 that has caused a failure or abnormality can be performed. improves.

  In addition, the measurement unit 5 of each branch passage 4 having the first and second vibrators 10 and 11 can be configured using unit parts of a small flow rate measuring device used for home use, and any size. There is also an advantage that the flow rate measuring device can be easily and easily handled.

(Embodiment 2)
FIG. 4 shows a large flow rate measuring device according to the second embodiment. In this embodiment, when there is an abnormality in the measurement unit 5 that measures the flow rate of each branch passage 4, the other measurement units 5 except for the abnormal measurement unit 5 are excluded. The total flow rate Q is measured based on the individual flow rate qm measured by the measurement unit 5.

  That is, in FIG. 4, the same elements as those in FIG. 2 are denoted by the same reference numerals and description thereof is omitted, and only different parts will be described. It is configured so that it can be detected when an abnormality occurs due to dust adhering to the surface of the child 10, 11 or a fault on the connection occurs.

  FIG. 5 is a flowchart showing the operation of the first flow rate measuring device according to the second embodiment, and the abnormality detection means 59 determines whether or not there is an abnormality in the measurement unit 5 during the individual flow rate measurement of each branch passage 4 (step 38).

  If an abnormality is detected in the first and second vibrators 10 and 11 of the measurement unit 5 at this time, the flow rate calculation means 18 based on the output of the abnormality detection means 59, except for the branch passage 4 where the abnormality occurs, The individual flow rate qm of each normal branch passage 4 is calculated, and the individual total flow rate Qm is calculated from the individual flow rate qm excluding the branch passage 4 in which the abnormality is detected (step 39). Thereafter, the individual total flow rate Qm calculated from the individual flow rates qm of the branch passages 4 excluding the branch passage 4 in which the abnormality has occurred is summed, and divided by the number of branch passages n excluding the branch passage 4 in which the abnormality has occurred. The average of the total flow rate Q flowing in the path 1 is calculated (step 35), and the control means 7 resets the outputs of the first and second vibrators 10 and 11 in the branch path 4 (step 40).

Then, at the next measurement, for example, after 2 seconds, the above operation is repeated again to measure the total flow rate Q of the flow path 1, but at that time, the measurement unit 5 of the branch passage 4 that has failed or is abnormal is reset. Then, since it is used again for the calculation of the total flow rate Q, the parameter of the total flow rate Q calculation is restored to the original number n, and the same high measurement accuracy as in the initial stage can be secured. If a failure or abnormality remains in the measurement unit 5 of the branch passage 4 even after resetting, the abnormality detection means 59 detects this, and finally the total result except for the measurement result of the branch passage 4 is the same as described above. The flow rate Q is calculated.

  As described above, in this large flow rate measuring device, when a failure or abnormality occurs for some reason in the first and second vibrators 10 and 11 of the measurement unit 5 of each branch passage 4, the abnormality detection means 59 detects this. Based on this detection, the flow rate calculation means 18 calculates the total flow rate Q of the flow path 1 by adding up the measurement results in the branch passage 4 and dividing the sum by the number n of the branch passages excluding the branch passage 4. Therefore, even if a failure or an abnormality occurs in the measurement unit 5 of the branch passage 4, the measurement can be continued without being unable to measure the flow rate as described in the conventional example, and the branch passage in which the abnormality or the like has occurred. High-precision measurement can be continued without being affected by the measurement result at 4.

Further, in this case, if it is set to notify the management company or the like via the Internet network by means of the communication means 9 in the same manner as when the failure of the flow rate measurement circuit unit 12 is detected, the previous period. In the same manner as in the above, on a holiday such as Sunday when the large flow rate measuring device is not used, repair such as replacement of the measuring unit 5 of the branch passage 4 that has caused a failure or abnormality can be performed. The measurement continuation period with the measurement accuracy reduced by the amount excluding the four measurement units 5 can be shortened, and the reliability of the user with respect to the measurement accuracy can be further improved.

  As described above, the present invention provides a large flow rate measuring device capable of measuring a large flow rate with high accuracy while simplifying the configuration and reducing power consumption. It is shown as an example in implementation, and it goes without saying that various modifications can be made within the scope of achieving the object of the present invention.

  For example, in each of the above-described embodiments, the flow rate sensor for measuring the flow rate is exemplified by using the first and second transducers 10 and 11 that are ultrasonic transducers. In particular, the sensor is particularly suitable for a sensor that easily attenuates ultrasonic waves.For example, a sensor that does not attenuate a measurement signal, such as a thermal flow sensor, is affected by variations in flow rate distribution. It may be.

  Further, when calculating the total flow rate Q of the entire flow path 1 from the individual total flow rate Qm of the branch passage 4, in each embodiment, the total value of the individual total flow rates Qm of each branch passage 4 is divided by the number of branch passages n. The average value is calculated by dividing the total value of the individual total flow rates Qm of the k branch passages 4 (k <n) at each measurement time by k, for example. It may be made to come out. There is also a method in which the total flow rate Q is finally obtained by changing the number of branch passages 4 to be measured at each measurement time.

  The branch passages 4 of the flow channel 1 preferably have the same cross-sectional area, but there is no problem even if they are different from each other.

  As described above, the present invention enables highly accurate measurement while simplifying the configuration and saving power, and can easily and easily correspond to any size measuring apparatus. A large flow rate measuring device can be provided, and can be widely applied to gases such as gas as well as liquids such as tap water and oil.

DESCRIPTION OF SYMBOLS 1 Flow path 2 Inlet 3 Outlet 4 Branch passage 5 Measuring unit 6 Opening / closing means 7 Control means 8 Switching means 9 Communication means 10 1st vibrator | oscillator (ultrasonic vibrator)
11 Second transducer (ultrasonic transducer)
DESCRIPTION OF SYMBOLS 12 Flow measurement circuit part 13 Transmitting means 14 Receiving means 15 Amplifying means 16 Time measuring means 18 Flow rate calculating means 19 Abnormality detecting means 59 Abnormality detecting means

Claims (6)

A flow path through which the fluid to be measured flows;
A plurality of branch passages provided between an inlet and an outlet of the flow path;
A measuring unit disposed in each of the plurality of branch passages;
A control unit having a flow rate measurement circuit unit for controlling the measurement unit to measure the flow rate of the branch passage, and a large flow rate measurement device comprising:
Furthermore, it comprises switching means for arbitrarily switching and connecting the measurement unit of each branch passage to the flow rate measurement circuit unit,
And the flow measurement circuit part is
The individual flow rate of each branch passage connected via the switching unit is calculated, and the individual total flow rate flowing through the flow channel is calculated for each branch passage based on the individual flow rate and averaged to flow through the flow channel. Large flow rate measuring device configured to calculate the total flow rate. The measurement unit has a configuration for detecting a flow rate based on a propagation time difference using an ultrasonic transducer disposed in each branch passage,
The flow rate measuring circuit section, the flow rate measuring characteristic of the correction constant by ultrasonic transducers comprise in each branch passage, calculates the individual flow by selectively using the correction constant with the switching by the switching Rikae means The large flow rate measuring device according to claim 1, which is configured. The control means, the flow rate with a plurality includes a measurement circuit section, the Switching Operation recombinant means the claim 1, the measuring unit of the branch passages to either a switching can be connected configuration of said plurality of flow measurement circuit section Or the large flow volume measuring apparatus of 2 description. Further comprising an abnormality detection means for detecting an abnormality of the flow rate measurement circuit unit;
4. The apparatus according to claim 3, wherein upon detecting an abnormality in the flow rate measurement circuit unit, the switching means switches and connects the measurement unit of each branch passage to a flow rate measurement circuit unit other than the flow rate measurement circuit unit that detected the abnormality. Flow measurement device. The abnormality detection means is configured to detect a measurement abnormality by the measurement unit of each branch passage,
When the abnormality detection means detects that the measurement by any of the measurement units of each branch passage is abnormal,
The control means resets the measurement of the branch passage,
The large flow rate measurement circuit unit according to claim 4, wherein the flow rate measurement circuit unit is configured to calculate a total flow rate flowing in the flow path based on an individual total flow rate calculated with an individual flow rate measured in a branch passage other than the branch passage. Flow measurement device. It said control means further comprises a communication means, a large flow rate measuring device according to claim 4 or 5 for communicating the abnormality of the flow rate measuring circuit unit to the outside.