JP4953001B2 - Flow rate measuring device, flow rate measuring method, and computer program - Google Patents

Description

  The present invention relates to a technique of a flow rate measuring device and a flow rate measuring method that can measure the flow rates of various fluids flowing inside a metal pipe using ultrasonic waves in a non-contact manner.

  As an ultrasonic flowmeter using an ultrasonic pulse, there is a technique disclosed in Patent Document 1.

  This ultrasonic flow meter is called a Doppler type, which emits an ultrasonic pulse from a transducer toward a measurement line in the fluid piping, and is an ultrasonic wave that is a reflected wave from suspended fine particles in the fluid flowing in the fluid piping. It is a device that analyzes the echo signal and determines the flow velocity distribution and flow rate of the fluid along the measurement line from the position and velocity of the suspended fine particles. The measurement line is formed by a beam of ultrasonic pulses emitted from the transducer.

  The ultrasonic flow meter can be applied to opaque fluid and opaque piping, can measure the fluid flowing in the fluid piping in a non-contact manner, and can measure the flow velocity distribution and flow rate in the fluid piping by line measurement along the measurement line. On the other hand, it can be applied to the flow velocity distribution and flow rate measurement of an opaque fluid, and has the advantage that it can be used to measure the flow of liquid metals such as mercury and sodium.

  However, it cannot be used unless there are reflectors that can reflect ultrasonic waves in the fluid, such as bubbles. A technique for compensating for this drawback is an ultrasonic flowmeter based on a propagation time difference method as shown in FIG. This is because the ultrasonic transducers face each other on the upstream side and the downstream side, and the ultrasonic waves that are transmitted and received are changed according to the flow velocity that the ultrasonic waves oscillated from the upstream side to the downstream side are faster because they are in the flow. The flow rate is determined using the principle of

Furthermore, as shown in FIG. 14, an ultrasonic flowmeter other than the Doppler method or the propagation time difference method described above that measures the average flow rate from the time difference between the oscillation and reception of the ultrasonic wave has a flow velocity by cross-correlation from the time difference of the reflected waves. There are also flowmeters that determine the distribution.
In this cross-correlation method, the measurement principle is to obtain the velocity of the reflector from the time difference of echo signals for a plurality of different pulses from the same reflector. Although accurate flow rate measurement based on the flow velocity distribution is possible, there is a drawback that it takes time for cross-correlation processing. For this reason, efficient cross-correlation processing with improved time resolution is desired.

Japanese Patent Application Laid-Open No. 2004-228620 describes a technique for improving the processing speed by setting a search window and specifying a region where cross-correlation processing is executed. This derives the frequency characteristic of the echo signal from the reflector, and sets the search window from this average value and standard deviation.
In order to find an echo signal from the same reflector, the first oscillation pulse is the “reference wave”, the second oscillation pulse is the “search wave”, and the correlation value between the reference wave and the search wave is large. Searching for the search wave within the search window, which is identified as an echo signal from the reflector, but the reflected wave that is not the search wave may be mistaken for the search wave Can reduce false positives.

JP 2000-97742 A Japanese Patent No. 3795510

  In the technique described in Patent Document 2, it is necessary to incorporate a considerable number of series of measurement data in order to accurately derive the frequency characteristics, resulting in a long processing time.

The problem to be solved by the present invention is to provide a technique for measuring a flow velocity distribution or flow rate that is easy to use by reducing the time of cross-correlation processing.
An object of the invention described in claims 1 to 4 is to provide a flow rate measuring device for measuring a flow velocity distribution or a flow rate that is easy to use by reducing the time of cross-correlation processing.
An object of the invention described in claims 5 to 8 is to provide a flow rate measuring method for measuring a flow velocity distribution or a flow rate that is easy to use by reducing the time of cross-correlation processing.
An object of the invention described in claims 9 to 12 is to provide a flow rate measurement program for measuring an easy-to-use flow velocity distribution or flow rate by shortening the time of cross-correlation processing.

(Claim 1)
The invention according to claim 1 relates to a flow rate measuring apparatus capable of using flow velocity measurement by a propagation time difference method and flow velocity measurement by a cross-correlation method for a pipe through which a fluid to be measured flows.
That is, an emission trigger oscillating means for outputting a trigger signal at a constant oscillation period, and an ultrasonic pulse is generated at a constant period in response to the output of the trigger signal from the emission trigger oscillating means, and the fluid pipe through which the fluid to be measured flows A first transducer that outputs an ultrasonic echo and receives an ultrasonic echo; a second transducer that is fixed at a position facing the downstream side of the pipe to which the first transducer is fixed; and the second transducer And the signal processing means for processing the ultrasonic echo received by the first transducer into an echo processing signal, and the echo processing signal processed by the signal processing means using the propagation time difference method / calculation means An average flow velocity calculating means for calculating a flow velocity, and an eco-process processed by the signal processing means. Using the fluctuation search window / calculation means and the cross-correlation method / calculation means, the position and velocity of the reflector along the measurement line are calculated, and the flow velocity distribution or flow rate of the fluid to be measured is calculated. And a flow velocity distribution / flow rate calculating means.
The propagation time difference method / calculation means includes an ultrasonic pulse received by the second transducer after the ultrasonic pulse oscillated from the first transducer has passed through the fluid to be measured, and an ultrasonic pulse oscillated from the second transducer. The average flow velocity in the pipe is calculated by analyzing the time difference from the ultrasonic pulse received by the first transducer after the sonic pulse has passed through the fluid to be measured.
The fluctuation search window / calculation means sets the size of the search window using the average flow velocity for each oscillation period of the trigger signal.
The cross-correlation method / calculation means generates an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured while either the first transducer or the second transducer oscillates. Alternatively, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation of the reference wave and the search wave in the search window for the echo processing signal received by either of the second transducers and processed by the signal processing means. It is characterized by that.

(Function)
First, the emission trigger oscillation means outputs a trigger signal at a constant oscillation period. The first transducer receives an output of the trigger signal from the emission trigger oscillating means, generates an ultrasonic pulse at a constant period, and outputs it along a measurement line in a fluid pipe through which the fluid to be measured flows. The second transducer also receives an output of the trigger signal from the emission trigger oscillating means, generates an ultrasonic pulse at a constant period, and outputs it along a measurement line in the fluid piping through which the fluid to be measured flows.
The ultrasonic echoes received by the second transducer and the first transducer are subjected to signal processing by the signal processing means into an echo processing signal.
From the echo processing signal processed by the signal processing means, the average flow velocity calculation means calculates the average flow velocity in the pipe using the propagation time difference method / calculation means. In other words, the said propagation time difference method, calculation means, an ultrasonic pulse the ultrasonic pulses oscillated from the first transducer is received by the second transducer after transmitted through the fluid to be measured, emitted from the second transducer The average flow velocity in the pipe is calculated by analyzing the time difference from the ultrasonic pulse received by the first transducer after the ultrasonic pulse transmitted through the fluid to be measured.
The calculated average flow velocity in the pipe is used for setting the size of the search window for each oscillation period of the trigger signal in the fluctuation search window / calculation means. Thereby, the search window can be determined efficiently and effectively.
On the other hand, the echo processing signal processed by the signal processing means is obtained by using the fluctuation search window / calculation means and the cross-correlation method / calculation means by the flow velocity distribution / flow rate calculation means, and the position of the reflector along the measurement line. And the speed are calculated. Since the search window is determined efficiently and effectively, the flow velocity distribution or flow rate of the fluid to be measured can be calculated accurately and quickly.

(Claim 2)
According to the second aspect of the present invention, the flow rate measurement by the propagation time difference method and the flow rate measurement by the cross-correlation method are performed on the pipe through which the fluid to be measured flows, in which the configuration of the flow measurement device according to the first aspect is slightly changed. The present invention relates to a flow measuring device that can be used.
The difference from the flow rate measuring apparatus according to claim 1 is that the emission trigger oscillation means for outputting the trigger signal at a constant oscillation period is not essential, and the size of the search window in the fluctuation search window / calculation means is set. This is a different method. That is, the fluctuation search window / calculation means of the flow rate measuring apparatus according to claim 2 is common in that the size of the search window is set using the average flow velocity calculated using the propagation time difference method / calculation means. It is different in that it is set with a set oscillation cycle.

  Here, the “predetermined oscillation period” is, for example, 0.1 second to 1 second. This range has been obtained empirically. If it is less than 0.1 seconds, it is easy to be affected by turbulent flow, and if it is longer than 1 second, the flow rate itself such as pump output fluctuation changes and is easily affected. For example, when calculating the flow velocity distribution and flow rate after acquiring echo signals collectively with “0.1 second oscillation period”, after calculating the average flow velocity only once, 100 trigger signals are generated, Ultrasonic echoes are acquired, and 99 flow velocity distributions and flow rates are calculated using the same search window obtained from the average flow velocity.

(Function)
The fluctuation search window / calculation unit sets the size of the search window using the average flow velocity separately calculated by the propagation time difference method / calculation unit, but sets the search window with a predetermined transmission cycle.
Since the search window is determined efficiently and effectively, the flow velocity distribution or flow rate of the fluid to be measured can be calculated accurately and quickly. This is possible using calculation means.

(Claim 3)
The invention according to claim 3 limits the flow rate measuring device according to claim 1 or claim 2.
That is, the fluctuation search window / calculation means temporarily sets a search range of a fluctuation window obtained from the average flow velocity value, and sets the search range to a predetermined multiple of the temporary setting.

(Glossary)
As the “predetermined multiple”, a numerical value specified empirically at each measurement site is adopted. For example, when the flow velocity is high or the pipe diameter is large, the calculation of the flow velocity distribution or flow rate can be made faster by using a smaller numerical value. Conversely, when the flow velocity is slow or the pipe diameter is small, the calculation of the flow velocity distribution or flow rate can be made more accurate by setting a larger numerical value.
It has been empirically understood from many measurement sites that it is reasonable to set the search range to twice the average flow velocity value, that is, to set the predetermined multiple to 2.

(Claim 4)
According to a fourth aspect of the present invention, in the first to third aspects of the invention, the average flow velocity calculated in real time by the propagation time difference method / calculation means and the flow velocity distribution data calculated by the cross-correlation method / calculation means are obtained. The present invention relates to a flow rate measuring apparatus characterized in that a database is created by associating and accumulating, and the flow velocity distribution data is extracted from the database using the average flow velocity calculated by the propagation time difference method / calculating means.

(Function)
The average flow velocity data is calculated in real time by the propagation time difference method / calculation means. Further, the flow velocity distribution data is calculated by the cross-correlation method / calculation means using the average flow velocity data. Then, the average flow velocity data and the flow velocity distribution data are stored in association with each other to form a database.
If the average flow velocity data can be calculated in real time by the propagation time difference method / calculation means, but the cross correlation method / calculation means is not suitable for outputting the flow velocity distribution or flow rate in real time, use a pre-built database. The flow velocity distribution data related to the average flow velocity data can be extracted, and the flow velocity distribution or the flow rate can be calculated and output.

(Claim 5)
The invention according to claim 5 is a method invention corresponding to the flow rate measuring device according to claim 1, wherein the flow velocity measurement by the propagation time difference method and the flow velocity measurement by the cross correlation method are performed on the pipe through which the fluid to be measured flows. This relates to a flow measurement method using
That is, an emission trigger oscillation procedure that outputs a trigger signal at a constant oscillation cycle, and the first transducer that receives the trigger signal output by the emission trigger oscillation procedure generates an ultrasonic pulse at a constant cycle, and the fluid to be measured flows The first ultrasonic transmission / reception procedure for outputting along the measurement line in the pipe and receiving the ultrasonic echo, and the second transducer fixed to the position facing the downstream side of the pipe to which the first transducer is fixed are super Processed by a second ultrasonic transmission / reception procedure for transmitting / receiving a sound pulse, a signal processing procedure for processing an ultrasonic echo received by the first transducer and the second transducer into an echo processing signal, and the signal processing procedure. Calculate the average flow velocity in the pipe using the propagation time difference method for the echo processing signal. And the echo processing signal processed in the signal processing procedure, using a variation search window and a cross-correlation method, to calculate the position and velocity of the reflector along the measurement line, A flow velocity distribution / flow rate calculation procedure for calculating a flow velocity distribution or a flow rate.
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is The average flow velocity in the pipe is calculated by analyzing the time difference from the ultrasonic pulse received by the first transducer after passing through the fluid to be measured.
The fluctuation search window sets the size of the search window using the average flow velocity for each oscillation period of the trigger signal.
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation between the reference wave and the search wave in the search window.

(Claim 6)
The invention according to claim 6 is a method invention corresponding to the flow rate measuring device according to claim 2, wherein flow velocity measurement by the propagation time difference method and flow velocity measurement by the cross-correlation method are performed on the pipe through which the fluid to be measured flows. This relates to a flow rate measurement method using.
That is, the first transducer outputs an ultrasonic pulse along a measurement line in a pipe through which the fluid to be measured flows, and receives a first ultrasonic transmission / reception procedure for receiving an ultrasonic echo, and a pipe on which the first transducer is fixed A second ultrasonic transmission / reception procedure in which a second transducer fixed to a position facing the downstream side of the ultrasonic wave transmits / receives an ultrasonic pulse, and ultrasonic processing received by the first transducer and the second transducer as an echo processing signal A signal processing procedure, an echo processing signal processed in the signal processing procedure, an average flow velocity calculation procedure for calculating an average flow velocity in the pipe using a propagation time difference method, and an echo processed in the signal processing procedure Calculating the position and velocity of the reflector along the measurement line using a variation search window and cross-correlation method for the processed signal; A flow velocity distribution / flow rate calculation procedure for calculating a flow velocity distribution or a flow rate of the fluid to be measured.
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is The average flow velocity in the pipe is calculated by analyzing the time difference from the ultrasonic pulse received by the first transducer after passing through the fluid to be measured.
The fluctuation search window sets the size of the search window using the average flow velocity at a predetermined set oscillation period.
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation between the reference wave and the search wave in the search window.

(Claim 7)
The invention according to claim 7 limits the flow rate measuring device according to claim 5 or 6.
That is, the fluctuation search window temporarily sets a search range of the fluctuation window obtained from the average flow velocity value, and sets the search range to a predetermined multiple of the temporary setting.

(Claim 8)
The invention according to claim 8 limits the flow rate measuring method according to any one of claims 5 to 7.
That is, a flow velocity distribution database creation procedure for associating the flow velocity distribution data calculated by the flow velocity distribution / flow velocity calculation means with the average flow velocity calculated by the average flow velocity calculation means and accumulating in the flow velocity distribution database; And a stored data utilization calculation procedure for calculating a flow velocity distribution or a flow rate of the fluid to be measured by extracting flow velocity distribution data corresponding to the average flow velocity data.

(Claim 9)
A ninth aspect of the present invention relates to a computer program for causing a computer to execute the flow rate measuring method according to the fifth aspect, and a flow velocity measurement and cross-correlation method using a propagation time difference method for a pipe through which a fluid to be measured flows. It is a computer program for making a computer perform the flow rate measuring method using the flow velocity measurement by.
The program includes an emission trigger oscillation procedure that outputs a trigger signal at a constant oscillation cycle, and the first transducer that receives the trigger signal output by the emission trigger oscillation procedure generates an ultrasonic pulse at a constant cycle, and The first ultrasonic transmission / reception procedure for receiving ultrasonic echoes while outputting along the measurement line in the pipe through which the pipe flows, and the second transducer fixed at a position facing the downstream side of the pipe to which the first transducer is fixed A second ultrasonic transmission / reception procedure for transmitting / receiving ultrasonic pulses, a signal processing procedure for processing an ultrasonic echo received by the first transducer and the second transducer into an echo processing signal, and processing by the signal processing procedure The calculated echo processing signal is averaged to calculate the average flow velocity in the pipe using the propagation time difference method. Calculate the position and velocity of the reflector along the measurement line from the flow velocity calculation procedure and the echo processing signal processed in the signal processing procedure, using a variation search window and a cross-correlation method, The flow rate distribution / flow rate calculation procedure for calculating the flow rate distribution or flow rate of the fluid is executed by a computer.
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is The average flow velocity in the pipe is calculated by analyzing the time difference from the ultrasonic pulse received by the first transducer after passing through the fluid to be measured.
The fluctuation search window sets the size of the search window using the average flow velocity for each oscillation period of the trigger signal.
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation between the reference wave and the search wave in the search window.

(Claim 10)
The invention according to claim 10 relates to a computer program for causing a computer to execute the flow rate measuring method according to claim 6.
That is, the first transducer outputs an ultrasonic pulse along a measurement line in a pipe through which the fluid to be measured flows, and receives a first ultrasonic transmission / reception procedure for receiving an ultrasonic echo, and a pipe on which the first transducer is fixed A second ultrasonic transmission / reception procedure in which a second transducer fixed to a position facing the downstream side of the ultrasonic wave transmits / receives an ultrasonic pulse, and ultrasonic processing received by the first transducer and the second transducer as an echo processing signal A signal processing procedure, an echo processing signal processed in the signal processing procedure, an average flow velocity calculation procedure for calculating an average flow velocity in the pipe using a propagation time difference method, and an echo processed in the signal processing procedure Calculating the position and velocity of the reflector along the measurement line using a variation search window and cross-correlation method for the processed signal; A flow rate distribution / flow rate calculation procedure for calculating a flow rate distribution or a flow rate of the fluid to be measured is executed by a computer.
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is The average flow velocity in the pipe is calculated by analyzing the time difference from the ultrasonic pulse received by the first transducer after passing through the fluid to be measured.
The fluctuation search window sets the size of the search window using the average flow velocity at a predetermined set oscillation period.
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation between the reference wave and the search wave in the search window.

(Claim 11)
The invention described in claim 11 limits the computer program described in claim 7,
If the search range of the fluctuation window obtained from the average flow velocity value is temporarily set, the search range is set to a predetermined multiple of the temporary setting.

(Claim 12)
The invention described in claim 12 limits the computer program described in claims 9-11.
A flow velocity distribution database creation procedure for associating the flow velocity distribution data calculated by the flow velocity distribution / flow velocity calculation means with the average flow velocity calculated by the average flow velocity calculation means and accumulating in the flow velocity distribution database;
By extracting flow velocity distribution data corresponding to predetermined average flow velocity data from the flow velocity distribution database, the stored data utilization calculation procedure for calculating the flow velocity distribution or flow rate of the fluid to be measured is executed by a computer. And

  The procedure defined in claim 12 is, for example, to output the flow velocity distribution or flow rate using the cross-correlation method / calculation means in real time, although the average flow velocity data can be calculated in real time by the propagation time difference method / calculation means. In cases where it is not suitable, it is selectively executed.

  If the computer program according to any one of claims 9 to 12 is installed in a predetermined information processing terminal and the first and second transducers are set, the flow measuring device according to any one of claims 1 to 4 is provided. It will be.

According to the first to fourth aspects of the present invention, it is possible to provide a flow rate measuring device that measures a flow velocity distribution or a flow rate that is easy to use by reducing the time of cross-correlation processing.
According to the invention described in claims 5 to 8, it is possible to provide a flow rate measuring method for measuring a flow velocity distribution or a flow rate that is easy to use by reducing the time of cross-correlation processing.
According to the invention described in claims 9 to 12, it is possible to provide a flow rate measurement program for measuring a flow velocity distribution or flow rate that is easy to use by reducing the time of cross-correlation processing.

  The present invention will be described with reference to embodiments and drawings. The drawings used here are FIGS. 1 to 12. 1, FIG. 3, FIG. 4 and FIG. 5 are block diagrams showing embodiments of the present invention. FIG. 2 is a conceptual diagram showing the principle of the present invention. FIG. 6 is a hardware configuration diagram. 7 to 12 are diagrams for explaining the processing procedure of the cross-correlation method.

(Figure 1)
FIG. 1 is a block diagram showing a first embodiment of the present invention. That is, in the first embodiment, the average flow velocity is calculated by the propagation time difference method / calculation system, the average flow velocity is used in setting the search window in the cross-correlation method / calculation system, and the flow velocity of the fluid to be measured by the cross-correlation method. The distribution or flow rate is calculated.

  The propagation time difference method / calculation system transmits ultrasonic waves from ultrasonic transducers facing each other upstream and downstream, and receives each other's ultrasonic waves at each transducer. The ultrasonic wave directed from the transducer installed upstream to the transducer installed downstream is faster than the ultrasonic wave directed from the transducer installed downstream to the transducer installed upstream. This is because it proceeds along the flow of the fluid. The propagation time difference method / calculation system calculates the flow velocity distribution by capturing the difference in propagation time.

On the other hand, the cross-correlation method / calculation system transmits an ultrasonic wave from a single ultrasonic transducer and receives a reflected wave reflected by the reflector. The ultrasonic wave to be transmitted has a reference wave and a search wave, and searches for them within the search window. If the range setting of the search window is large, there are few mistakes and the calculation of the flow velocity distribution is accurate. However, if the range is too large, it takes a lot of calculation time.
Therefore, by setting the search window using the average flow velocity calculated by the propagation time difference method / calculation system described above, a reasonable search range is obtained, the flow velocity distribution or flow rate is calculated, and the calculation result is output to the output means. It is what is output. In order to show the case where the flow velocity distribution is output instead of the unit time flow rate, it is indicated by a two-dot broken line in FIG.

(Figure 2)
FIG. 2 illustrates the reference window, the echo signal of the reference wave, the search window, and the echo signal of the search window, and conceptually shows the procedure for determining the search range using the average flow velocity therefrom. .
Conventionally, in the variable search window method in which the size of the search window is set for each oscillation period τ of the emission trigger, the so-called 3σ rule of statistics is calculated from the average frequencies fG and σ calculated by FFT of the digital ultrasonic echo signal at each τ. (In the normal distribution, 99.7% of the whole is included in the range of the average value ± 3σ), the frequency band that can appear is regarded as the range of the average frequency fG ± 3σ, and the velocity of the ultrasonic reflector that can exist The minimum value umin and the maximum value umax are determined from fG + 3σ and fG-3σ, the search window sizes Δτmin and Δτmax are determined, and the search wave is searched in this range (range (a) in the figure). .
The calculation for obtaining the size of the search window is limited in scope using the 3σ rule, but requires enormous calculation.

On the other hand, in the present invention, the position predicted from the average flow velocity calculated by the propagation time difference method and the predicted position (the position and range indicated by (d) in the figure) are the center, and the search range is an integer of the average flow velocity. By setting it to double, the size of the search window is determined (range (b) in the figure). This makes it possible to make the search range smaller than the 3σ rule.
Since the flow direction is specified, one search window is not necessary, and one of the search windows can be specified (range (c) in the figure).

(Figure 3)
In FIG. 3, the data flow is indicated by numerals and used in the following description.
The second embodiment shown in FIG. 3 is the same as the first embodiment in that the average flow velocity data is calculated in the propagation time difference method / calculation system and sent to the cross-correlation method / calculation system (1) ( The case of the same processing procedure as in the first embodiment is indicated by a two-dot broken line).
Once the flow velocity distribution data can be calculated by the propagation time difference method / calculation system, it is compiled into a database by accumulating it in the flow velocity distribution database together with the aforementioned average flow velocity data (2, 3).
Then, relevant relevant data is extracted from the flow velocity distribution database, and the flow velocity distribution or flow rate is calculated (4).

  According to this embodiment, the average flow velocity data can be calculated in real time by the propagation time difference method / calculation means, but the cross-correlation method / calculation means is not suitable for outputting the flow velocity distribution or flow rate in real time. Even so, the flow velocity distribution or flow rate can be calculated and output.

(Fig. 4)
In FIG. 4, the first embodiment described above is indicated by a solid line, and a portion related only to the second embodiment is indicated by a two-dot broken line.
An emission trigger oscillation means oscillates a trigger signal for the first and second transducers. Then, the ultrasonic pulse oscillation means provided in each transducer transmits an ultrasonic pulse toward the fluid to be measured in the pipe. And while receiving the ultrasonic pulse which mutually oscillated in each transducer, it receives a necessary reflected wave. In this illustrated example, the first transducer receives a reflected wave (ultrasonic echo) by an ultrasonic pulse oscillated by itself and an ultrasonic pulse oscillated by the second transducer. The second transducer receives only the ultrasonic pulse generated by the first transducer.

  The ultrasonic pulse and ultrasonic echo received by each transducer are subjected to appropriate signal processing by the signal processing means. As shown in FIG. 5, although not shown in this figure, filtering by a low-pass filter, analog-digital conversion by an AD converter, wall filtering processing by a wall filter, and the like.

The processing signal processed by the signal processing means is sent necessary data to the average flow velocity calculation means and the flow velocity distribution / flow rate calculation means.
In the average flow velocity calculation means, the average flow velocity data is calculated by the propagation time difference method calculation means. When an average flow velocity database for accumulating average flow velocity data is provided, it is databased together with related data.

  In the flow velocity distribution / flow rate calculation means, the fluctuation search window / calculation means searches for the search wave and the reference wave within the search window. In the search window range setting, the above average flow velocity data is used. Then, the flow velocity distribution or flow rate is calculated by the cross-correlation / calculation means, and the calculation result is output via the output means.

(Fig. 5)
FIG. 5 illustrates in detail the signal processing means in the first embodiment.
That is, the signal processing means includes a low-pass filter 30b, an AD converter 32, and a wall filter processing unit 33. An unnecessary frequency component is removed by the low-pass filter 30b, and analog-digital conversion is executed by the AD converter 32. Then, the clutter noise is removed by the wall filter of the wall filter processing unit 33.
The processing signal processed as described above is used in the average flow velocity calculation means and the flow velocity distribution / flow rate calculation means 37.

(Fig. 6)
FIG. 6 schematically shows the system configuration of the first or second embodiment described above.
The personal computer ("PC" 11 in the figure) and the ultrasonic flow velocity distribution and flow rate measurement program that can be read and executed by the personal computer 11 cooperate with each other, and the ultrasonic flow velocity distribution is applied to the pipe 18 through which the fluid to be measured flows. Functions as a meter and flow meter. That is, the ultrasonic velocity distribution and flow measurement program is installed in the hard disk built in the personal computer 11.

In the pipe 18, a first transducer 15 is fixed on the upstream side, and a second transducer 15 a is fixed on the downstream side facing the first transducer 15.
The ultrasonic transducers 15 and 15a are installed on the pipe 18 from the outside at a predetermined installation angle θ. The ultrasonic pulse transmitted from the first transducer 15 is incident and suspended (mixed) in the fluid to be measured 17 flowing in the pipe 18 along the measurement line ML shown in FIG. It is reflected by. The reflected wave reflected by the ultrasonic reflector (bubble 48) returns to the ultrasonic transducer 15. The ultrasonic pulse transmitted from the second transducer 15a is also received.
On the other hand, the second transducer 15 a receives the ultrasonic pulse transmitted from the first transducer 15.

Although illustration is omitted, the above-described transducers 15 and 15a are generally installed in the pipe 18 via an acoustic coupler in order to match the acoustic impedance.
At the time of ultrasonic flow velocity distribution and flow rate measurement, for example, processing operations associated with measurement such as control of the frequency of ultrasonic pulses transmitted by the transducers 15 and 15a and gain adjustment when receiving reflected waves (hereinafter referred to as “basic”). The “processing operation”) has various functions realized by a preset basic processing program. The basic processing program is recorded and stored in a recording means readable by the personal computer 11 such as a hard disk built in the personal computer 11, for example.

(Fig. 7)
The cross-correlation / calculation means executes a process for calculating the flow velocity, but it can be repeated to create and store a flow velocity profile. The created profile is used for error correction of the calculated flow velocity.
The flow velocity distribution is made into a database together with related data. By providing the data of flow velocity distribution in a database, it can be used when it is difficult to calculate real-time average flow velocity data.

(Fig. 8)
FIG. 8 details the signal processing means of FIG. 5 and explains the relationship between the trigger signal and ultrasonic echo signal reception waveform and the sampling timing of the AD converter 32.
The horizontal axis represents the time axis, the vertical axis represents the signal level, the upper stage shows the time change of the trigger signal, the middle stage shows the time change of the received waveform of the ultrasonic echo signal, and the lower stage shows the sampling timing of the AD converter 32. As shown in the upper part of FIG. 8, for example, pulse signals are output one after another as the trigger signal at predetermined time (τ) intervals. The timing of reception of the ultrasonic echo signal and the sampling of the AD converter 32 are controlled in accordance with the timing of this trigger signal.

  As shown in the lower part of FIG. 8, the AD converter 32 digitally samples the ultrasonic echo signal for a very short time width, for example, every 1 μs, and obtains the digital ultrasonic echo signal, that is, the time series of the required number of series. Data (for example, 512 series) is acquired. When the AD converter 32 completes acquisition of time series data for the required number of series, the wall filter processing unit 33 executes WF processing on the digital ultrasonic echo signal as a wall filter (WF) processing step. The wall filter processing unit 33 reduces clutter noise. The ultrasonic echo signal for which the WF process has been completed is subjected to signal analysis by a signal analysis procedure.

  The signal analysis is to obtain a velocity distribution along the measurement line (diameter direction line of the stainless steel pipe) ML of the fluid 17 flowing in the pipe 18 by analyzing the ultrasonic echo signal using the cross-correlation method. The flow rate is obtained by obtaining a velocity distribution along the line and integrating the obtained flow velocity distribution along the internal area of the pipe 18.

  The signal analysis procedure includes a reflector position / velocity calculation step for calculating the position and velocity of the ultrasonic reflector group in the fluid, and a position of the ultrasonic reflector group in the fluid calculated in the reflector position / velocity calculation step. And a flow rate calculation step of calculating a flow rate distribution of the fluid from the velocity, and a flow rate calculation step of calculating the flow rate by performing an integral operation along the internal area of the pipe 18 with respect to the flow rate distribution calculated in the flow rate distribution calculation step.

  In the signal analysis of the ultrasonic echo signal as the signal analysis procedure, first, the reflector position / velocity calculation unit 36 calculates the position and velocity of the ultrasonic reflector group as a reflector position / velocity calculation step. The position and velocity of the ultrasonic reflector group are calculated for a very short time width, for example, a continuous series of digital ultrasonic echo signals sampled 512 series every 1 μs, that is, reflected waves included in the nth series (see Wave) 45 and the cross-correlation between the reflected wave (search wave) 46 included in the (n + 1) th series (n is an integer satisfying 1 <n <511).

  The calculation of the cross-correlation between the reference wave 45 and the search wave 46 as the cross-correlation calculation processing step is performed by setting the size of the search window using the variation search window method, and in the necessary search range in the search wave 46 Cross correlation with wave 45 is performed from n = 1 to n = 511. Then, the cross-correlation between the reference wave 45 and the search wave 46 is calculated, and when the correlation value is equal to or greater than a certain value (threshold value), a phase specifying step that regards the reflected wave from the same ultrasonic reflector is executed, Then, the phase difference between the reference wave 45 and the search wave 46 specified in the phase difference calculation step is obtained, and the position / velocity calculation step for calculating the position and velocity of the ultrasonic reflector from the phase difference is executed.

  In this way, when the correlation value between the reference wave 45 and the search wave 46 is a certain value (threshold value) or more, it is regarded as a reflected wave from the same ultrasonic reflector and the ultrasonic wave is reflected in the fluid 17. The position and speed of each ultrasonic reflector are calculated. Then, the flow velocity distribution calculating unit 37 calculates the flow velocity distribution of the fluid 17 to be measured from the position and velocity of the ultrasonic reflector group calculated as the flow velocity distribution calculating step.

  The flow velocity distribution calculation unit 37 calculates the flow velocity distribution of the fluid to be measured 17 to be measured from the position and velocity data of the obtained ultrasonic reflector group. The calculated flow velocity distribution of the fluid 17 to be measured is regarded as the velocity of the ultrasonic reflector group suspended in the fluid 17, and the pipe 18 (stainless steel is obtained from the position and velocity data of the obtained ultrasonic reflector group. The relationship between the position of the pipe) and the velocity of the ultrasonic reflector group at that position, that is, the flow velocity distribution of the fluid 17 in the pipe 18 is calculated.

  The signal analysis procedure includes a reflector position / velocity calculation step, a flow velocity distribution calculation step, and a flow rate calculation step. However, the signal analysis procedure includes a reflector position / velocity calculation step and a flow velocity distribution calculation step. The form provided with. In this case, the ultrasonic flow velocity distribution meter and the flow meter 10 calculate only the flow velocity distribution of the fluid 17 to be measured in the pipe 18 and do not calculate the flow rate, and the flow velocity is displayed on a display means such as a display of the personal computer 11. The distribution is displayed.

(Fig. 9)
FIG. 9 is a process for explaining the ultrasonic flow velocity distribution and flow measurement processing method performed by the personal computer 11 executing the ultrasonic flow velocity distribution and flow measurement program in the ultrasonic flow velocity distribution meter and flow meter shown in FIG. FIG.
That is, the ultrasonic flow velocity distribution and flow rate measurement processing method obtains the flow velocity distribution and flow rate of the fluid 17 by performing signal processing on the received ultrasonic echo signal and signal analysis of the ultrasonic echo signal after the signal processing. A signal analysis procedure.

  The signal processing procedure includes a BPF processing step for performing BPF processing for extracting the same frequency band as the used ultrasonic wave from the received ultrasonic echo signal, an AD conversion step for AD converting the ultrasonic echo signal, and an ultrasonic echo signal. And a WF processing step for reducing clutter noise components superimposed on the.

  The signal analysis procedure includes a reflector position / velocity calculating step for calculating the position and velocity of the ultrasonic reflector group in the fluid 17 to be measured, and the ultrasonic reflector group calculated in the reflector position / velocity calculating step. A flow velocity distribution calculating step of calculating a flow velocity distribution of the fluid from the position and velocity, and a flow rate calculating step of calculating a flow rate of the fluid 17 from the flow velocity distribution calculated in the flow velocity distribution calculating step.

First, arithmetic processing means such as a CPU built in the personal computer 11 reads out and executes the ultrasonic flow velocity distribution and the flow measurement PG 12, and performs a signal processing procedure (steps S1 to S3) and a signal analysis procedure (steps S4 to S6). Execute.
In the signal processing procedure in the ultrasonic flow velocity distribution and flow rate measurement processing method, the BPF processing step is performed in step S1, the AD conversion step is performed in step S2, and the WF processing step is performed in step S3.

(Fig. 10)
FIG. 10 is a process flowchart showing more detailed processing steps of the reflector group position / velocity calculating step (step S4) in the signal analysis procedure.
The reflector group position / velocity calculating step in step S4 includes a cross-correlation calculating step (step S21), a phase specifying step (step S22), a phase difference calculating step (step S23), and a position / velocity calculating step (step). S24) and a search completion determination step (step S25).

  In the reflector group position / velocity calculating step, first, a cross-correlation calculation processing step is performed in step S21, and the cross-correlation between the reference wave 45 and the search wave 46 by the cross-correlation method is calculated to calculate a correlation value. The correlation value is calculated by setting the size of the search window of the search wave 46 by the variable search window method and calculating the cross-correlation with the reference range of the reference wave 45 in the search range of the search wave 46. . When the calculation of the correlation value is completed, the cross-correlation calculation processing step (step S21) is completed, and then the phase specifying step is performed in step S22.

  In the phase identification step of step S22, the phase of the search wave 46 having a relationship in which the correlation value obtained in the cross correlation calculation processing step (step S21) is equal to or greater than the threshold value s is identified. The threshold s is set before or during execution of the PG. The phase identification step (step S22) is completed, and then a phase difference calculation step is performed in step S23.

In the phase difference calculation step of step S23, the phase difference between the phase of the identified search wave 46 and the phase referred to by the reference wave 45 is calculated. When the calculation of the phase difference is completed, the phase difference calculation step (step S23) is completed, and then the position / velocity calculation step is performed in step S24.
In the position / velocity calculating step of step S24, the position and velocity of the ultrasonic reflector within the search range of the search wave 46 are calculated from the calculated phase difference. When the calculation of the position and velocity of the ultrasonic reflector within the search range of the search wave 46 is completed, the position / velocity calculation step (step S24) is completed, and then the search completion determination step of step S25 is performed.

  In the search completion determination step of step S25, it is determined whether or not the search has been completed for all search ranges searched in the search wave 46. If the search has not been completed for all search ranges (NO in step S25), the process proceeds to step S21, and the processing steps after step S21 are repeated. By repeating the processing steps after step S21, the position and speed of the ultrasonic reflector group flowing in the fluid 17 are calculated. On the other hand, when the search has been completed for all the search ranges (YES in step S25), the reflector group position / velocity calculating step is terminated.

  When the reflector group position / velocity calculating step (step S4) is completed in the signal analysis procedure, the flow velocity distribution calculating step (step S5) is subsequently performed. In the flow velocity distribution calculating step in step S5, the relationship between the position and velocity of the ultrasonic reflector group, that is, the flow velocity distribution is calculated from the reflector group position and velocity calculated in the reflector group position / velocity calculating step. When calculating the flow velocity distribution, the velocity of all the ultrasonic reflectors acquired at the same position at the same corresponding time (for example, corresponding time τ1) in each series is calculated by averaging or squaring.

  When the flow velocity distribution is calculated, the flow velocity distribution calculation step (step S5) is completed, and then the flow rate calculation step (step S6) is performed. In the flow rate calculation step of step S6, the flow rate is calculated by integrating the flow velocity distribution in the calculated pipe 18 along the internal area of the pipe 18. At this time, information necessary for the integral calculation other than the flow velocity distribution such as the inner diameter D of the pipe 18 is input and set before the ultrasonic flow velocity distribution and flow rate measurement processing is performed.

  When the calculation of the flow rate is completed, the flow rate calculation step (step S6) is completed, and the signal analysis procedure completes all the processing steps. When the signal analysis procedure is completed, the entire processing procedure in the ultrasonic flow velocity distribution and flow rate measurement processing method is completed. The display of the ultrasonic flow velocity distribution and the flow measurement processing result is performed by reading out and executing the basic processing program after the arithmetic processing means such as the CPU built in the personal computer 11 completes the entire processing procedure of the ultrasonic flow velocity distribution and flow measurement program. That is done.

(Fig. 11)
FIG. 11 shows the basis on which it is possible to assume that a quarter of the measurement line (a quarter of the diameter) is an average flow velocity when a flow velocity distribution profile is created.
That is, the fluid to be measured in the fluid pipe has a maximum speed near the center of the pipe and zero on the inner wall of the pipe. Therefore, even if the calculation is performed assuming that the quarter of the measurement line is the average flow velocity, a large error does not occur. This is because the average flow velocity data is not used to directly calculate the flow velocity but only to set the search window.

(Wall filter)
In the ultrasonic flow velocity distribution meter and the flow meter 10, when the metal pipe 18 is used as the fluid pipe that guides the fluid 17 to be measured, the flow velocity distribution and the flow rate of the measurement target fluid 17 are measured. In addition, a noise component called clutter noise is significantly superimposed. This noise component can lead to incorrect tracer particle position and velocity information. In order to avoid this, the clutter noise reduction processing by the WF processing unit 33 described above is executed. Hereinafter, a clutter noise reduction processing method using WF will be described.

(Fig. 12)
FIG. 12 illustrates a time series change of the trigger signal, the ultrasonic echo signal, and the clutter noise.
Each series of clutter noise is substantially the same in any series, and is a noise that attenuates and oscillates as time passes. The clutter noise is noise in which the noise corresponding to the number of series slides and is superimposed by the time difference τ, and thus has various frequency components and n peaks for each start time of the 1st to nth series.

In conventional filtering processing using LPF (low pass filter) and HPF (high pass filter) and filtering processing using BPF (band pass filter), clutter noise having various frequency components cannot be effectively filtered. The part where this occurs is regarded as the reflected wave of the ultrasonic pulse from the tracer particle group, and the clutter noise is erroneously analyzed as an effective signal.
Therefore, a filtering process (WF process) using a WF (wall filter) is executed to prevent the clutter noise from being recognized as an effective signal and to sufficiently reduce the clutter noise with respect to the effective signal. In the WF process, first, a corresponding time echo level signal is acquired from a digital ultrasonic echo signal.

  The present invention can be used in the flow meter and current meter manufacturing industry, the flow meter and current meter sales and maintenance business, the plant maintenance and maintenance business, and the computer program production and maintenance business related to plant control. There is.

It is a block diagram which shows 1st embodiment which concerns on this invention. It is a conceptual diagram which shows the setting principle of the search window in this invention. It is a block diagram which shows 1st embodiment which concerns on this invention. It is a block diagram which shows 1st and 2nd embodiment which concerns on this invention. It is a block diagram which shows 1st and 2nd embodiment which concerns on this invention. It is a conceptual diagram which shows the hardware constitutions of 1st to 3rd embodiment which concerns on this invention. It is a conceptual diagram which shows the preparation procedure of the flow velocity profile. It is explanatory drawing explaining the relationship between a trigger signal and an ultrasonic echo signal reception waveform, and the timing of sampling of AD converter. It is a processing flowchart which shows the signal processing procedure and signal analysis procedure of the ultrasonic flow velocity distribution and flow measurement processing method according to the present invention. It is a processing flowchart which shows the reflector position and speed calculation process by the flow velocity distribution and flow measurement processing method according to the present invention. It is a conceptual diagram which shows the basis which can assume that the point (1/4 of a diameter) of a measurement line is an average flow velocity. It is explanatory drawing explaining the time series change (lower stage) of a trigger signal (upper stage), an ultrasonic echo signal (middle stage), and clutter noise. It is a conceptual diagram which shows the principle of a propagation time difference method. It is a conceptual diagram which shows the principle of a cross correlation method.

Explanation of symbols

10 Flow meter 11 Personal computer (PC)
14 signal line 14a signal line 15 transducer 15a ultrasonic pulse oscillator 17 fluid to be measured 18 piping (metal piping)
30b Low-pass filter 32 AD converter 33 Wall filter processing unit 37 Flow velocity distribution / flow rate calculation means 45 Reference wave 46 Search wave 48 Bubble (reflector)

Claims (12)

A flow rate measuring device that can use flow velocity measurement by a propagation time difference method and flow velocity measurement by a cross-correlation method for a pipe through which a fluid to be measured flows,
An emission trigger oscillation means for outputting a trigger signal at a constant oscillation period;
A first transducer that receives an output of a trigger signal from the emission trigger oscillation means, generates ultrasonic pulses at a constant period, outputs the ultrasonic pulses along a measurement line in a pipe through which a fluid to be measured flows, and receives an ultrasonic echo When,
A second transducer for transmitting and receiving ultrasonic pulses while being fixed to a position facing the downstream side of the pipe to which the first transducer is fixed;
Signal processing means for processing the ultrasonic echo received by the second transducer and the first transducer into an echo processing signal;
The echo processing signal processed in the signal processing means, an average flow velocity calculating means for calculating an average flow velocity in the pipe using a propagation time difference method / calculating means,
The echo processing signal processed in the signal processing means is calculated using the variation search window / calculation means and the cross-correlation method / calculation means to calculate the position and velocity of the reflector along the measurement line, and to be measured A flow velocity distribution / flow rate calculating means for calculating the flow velocity distribution or flow rate of the fluid,
The propagation time difference method / calculation means includes an ultrasonic pulse received by the second transducer after the ultrasonic pulse oscillated from the first transducer has passed through the fluid to be measured, and an ultrasonic pulse oscillated from the second transducer. By calculating the average flow velocity in the pipe by analyzing the time difference with the ultrasonic pulse received by the first transducer after the sonic pulse has passed through the fluid to be measured,
The fluctuation search window / calculation means sets the size of the search window using the average flow velocity for each oscillation period of the trigger signal, and the cross-correlation method / calculation means includes the first transducer or the second Either one of the transducers oscillates, and either the first transducer or the second transducer receives an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured, and the signal processing means outputs a signal. A flow rate measuring apparatus characterized in that, for a processed echo processing signal, a flow velocity distribution or a flow rate of a fluid to be measured is calculated from a cross-correlation between a reference wave and a search wave in the search window. A flow rate measuring device that can use flow velocity measurement by a propagation time difference method and flow velocity measurement by a cross-correlation method for a pipe through which a fluid to be measured flows,
A first transducer for outputting an ultrasonic pulse along a measurement line in a pipe through which a fluid to be measured flows, and receiving an ultrasonic echo;
A second transducer for transmitting and receiving ultrasonic pulses while being fixed to a position facing the downstream side of the pipe to which the first transducer is fixed;
Signal processing means for processing the ultrasonic echo received by the second transducer and the first transducer into an echo processing signal;
The echo processing signal processed in the signal processing means, an average flow velocity calculating means for calculating an average flow velocity in the pipe using a propagation time difference method / calculating means,
The echo processing signal processed in the signal processing means is calculated using the variation search window / calculation means and the cross-correlation method / calculation means to calculate the position and velocity of the reflector along the measurement line, and to be measured A flow velocity distribution / flow rate calculating means for calculating the flow velocity distribution or flow rate of the fluid,
The propagation time difference method / calculation means includes an ultrasonic pulse received by the second transducer after the ultrasonic pulse oscillated from the first transducer has passed through the fluid to be measured, and an ultrasonic pulse oscillated from the second transducer. By calculating the average flow velocity in the pipe by analyzing the time difference with the ultrasonic pulse received by the first transducer after the sonic pulse has passed through the fluid to be measured,
The fluctuation search window / calculation means sets the size of the search window using the average flow velocity at a predetermined unity oscillation period,
The cross-correlation method / calculation means generates an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured while either the first transducer or the second transducer oscillates. Alternatively, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation of the reference wave and the search wave in the search window for the echo processing signal received by either of the second transducers and processed by the signal processing means. A flow rate measuring device characterized by that.   3. The fluctuation search window / calculation means, when temporarily setting a search range of a fluctuation window obtained from the average flow velocity value, sets the search range to a predetermined multiple of the temporary setting. The flow measuring device according to any one of the above. A flow velocity distribution database that accumulates the flow velocity distribution data calculated by the flow velocity distribution / flow velocity calculation means and the average flow velocity calculated by the average flow velocity calculation means in association with each other;
The flow velocity distribution / flow rate calculation means can calculate a flow velocity distribution or a flow rate of a fluid to be measured by extracting flow velocity distribution data corresponding to predetermined average flow velocity data from the flow velocity distribution database. The flow rate measuring device according to any one of claims 1 to 3. A flow rate measurement method using flow velocity measurement by a propagation time difference method and flow velocity measurement by a cross-correlation method for a pipe through which a fluid to be measured flows,
An emission trigger oscillation procedure that outputs a trigger signal at a constant oscillation period;
Upon receiving the trigger signal output from the emission trigger oscillation procedure, the first transducer generates an ultrasonic pulse at a constant period, outputs it along the measurement line in the pipe through which the fluid to be measured flows, and receives an ultrasonic echo. A first ultrasonic transmission / reception procedure;
A second ultrasonic transmission / reception procedure in which the second transducer fixed to a position facing the downstream side of the pipe to which the first transducer is fixed transmits and receives an ultrasonic pulse;
A signal processing procedure for signal processing the ultrasonic echoes received by the first transducer and the second transducer into an echo processing signal;
The echo processing signal processed in the signal processing procedure, an average flow velocity calculation procedure for calculating the average flow velocity in the pipe using the propagation time difference method,
The echo processing signal processed in the signal processing procedure is used to calculate the position and velocity of the reflector along the measurement line using a fluctuation search window and a cross-correlation method. A flow velocity distribution / flow rate calculation procedure for calculating the flow rate,
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is By calculating the average flow velocity in the pipe by analyzing the time difference with the ultrasonic pulse received by the first transducer after passing through the measured fluid,
The variation search window is to set the size of the search window using the average flow velocity for each oscillation period of the trigger signal,
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation of the reference wave and the search wave in the search window. A flow measurement method characterized by A flow rate measurement method using flow velocity measurement by a propagation time difference method and flow velocity measurement by a cross-correlation method for a pipe through which a fluid to be measured flows,
A first ultrasonic transmission / reception procedure in which the first transducer outputs an ultrasonic pulse along a measurement line in a pipe through which the fluid to be measured flows, and receives an ultrasonic echo;
A second ultrasonic transmission / reception procedure in which the second transducer fixed to a position facing the downstream side of the pipe to which the first transducer is fixed transmits and receives an ultrasonic pulse;
A signal processing procedure for signal processing the ultrasonic echoes received by the first transducer and the second transducer into an echo processing signal;
The echo processing signal processed in the signal processing procedure, an average flow velocity calculation procedure for calculating the average flow velocity in the pipe using the propagation time difference method,
The echo processing signal processed in the signal processing procedure is used to calculate the position and velocity of the reflector along the measurement line using a fluctuation search window and a cross-correlation method. A flow velocity distribution / flow rate calculation procedure for calculating the flow rate,
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is By calculating the average flow velocity in the pipe by analyzing the time difference with the ultrasonic pulse received by the first transducer after passing through the measured fluid,
The fluctuation search window is set with a predetermined oscillation period, and sets the size of the search window using the average flow velocity,
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation of the reference wave and the search wave in the search window. A flow measurement method characterized by The variation search window, the When the search range of the variation window obtained from the average flow velocity value provisionally set, claim 5 or claim 6, characterized in that to set the search range to a predetermined multiple of the temporarily set The flow measurement method described in 1. A flow velocity distribution database creation procedure for associating the flow velocity distribution data calculated by the flow velocity distribution / flow velocity calculation means with the average flow velocity calculated by the average flow velocity calculation means and accumulating in the flow velocity distribution database;
The accumulated data utilization calculation procedure for calculating the flow velocity distribution or flow rate of the fluid to be measured by extracting flow velocity distribution data corresponding to predetermined average flow velocity data from the flow velocity distribution database. The flow rate measuring method according to any one of claims 5 to 7. A computer program for causing a computer to execute a flow rate measurement method using a flow velocity measurement by a propagation time difference method and a flow velocity measurement by a cross-correlation method for a pipe through which a fluid to be measured flows,
The program consists of an emission trigger oscillation procedure that outputs a trigger signal at a fixed oscillation period,
Upon receiving the trigger signal output from the emission trigger oscillation procedure, the first transducer generates an ultrasonic pulse at a constant period, outputs it along the measurement line in the pipe through which the fluid to be measured flows, and receives an ultrasonic echo. A first ultrasonic transmission / reception procedure;
A second ultrasonic transmission / reception procedure in which the second transducer fixed to a position facing the downstream side of the pipe to which the first transducer is fixed transmits and receives an ultrasonic pulse;
A signal processing procedure for signal processing the ultrasonic echoes received by the first transducer and the second transducer into an echo processing signal;
The echo processing signal processed in the signal processing procedure, an average flow velocity calculation procedure for calculating the average flow velocity in the pipe using the propagation time difference method,
The echo processing signal processed in the signal processing procedure is used to calculate the position and velocity of the reflector along the measurement line using a fluctuation search window and a cross-correlation method. The flow rate distribution / flow rate calculation procedure for calculating the flow rate is executed by a computer.
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is By calculating the average flow velocity in the pipe by analyzing the time difference with the ultrasonic pulse received by the first transducer after passing through the measured fluid,
The fluctuation search window sets the size of the search window using the average flow velocity for each oscillation period of the trigger signal,
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation of the reference wave and the search wave in the search window. A computer program characterized by the above. A computer program for causing a computer to execute a flow rate measurement method using a flow velocity measurement by a propagation time difference method and a flow velocity measurement by a cross-correlation method for a pipe through which a fluid to be measured flows,
The program includes a first ultrasonic transmission / reception procedure in which a first transducer outputs an ultrasonic pulse along a measurement line in a pipe through which a fluid to be measured flows and receives an ultrasonic echo;
A second ultrasonic transmission / reception procedure in which the second transducer fixed to a position facing the downstream side of the pipe to which the first transducer is fixed transmits and receives an ultrasonic pulse;
A signal processing procedure for signal processing the ultrasonic echoes received by the first transducer and the second transducer into an echo processing signal;
The echo processing signal processed in the signal processing procedure, an average flow velocity calculation procedure for calculating the average flow velocity in the pipe using the propagation time difference method,
The echo processing signal processed in the signal processing procedure is used to calculate the position and velocity of the reflector along the measurement line using a fluctuation search window and a cross-correlation method. The flow rate distribution / flow rate calculation procedure for calculating the flow rate is executed by a computer.
In the propagation time difference method, the ultrasonic pulse oscillated from the first transducer is transmitted through the fluid to be measured and then received by the second transducer, and the ultrasonic pulse oscillated from the second transducer is By calculating the average flow velocity in the pipe by analyzing the time difference with the ultrasonic pulse received by the first transducer after passing through the measured fluid,
The fluctuation search window is set with a predetermined oscillation period, and sets the size of the search window using the average flow velocity,
In the cross-correlation method, either the first transducer or the second transducer oscillates, and an ultrasonic echo generated by being reflected by a reflector in the fluid to be measured is generated by the first transducer or the first transducer. For the echo processing signal received by either of the two transducers and processed by the signal processing means, the flow velocity distribution or flow rate of the fluid to be measured is calculated from the cross-correlation of the reference wave and the search wave in the search window. A computer program characterized by the above.   11. The variation search window, when temporarily setting a search range of the variation window obtained from the average flow velocity value, sets the search range to a predetermined multiple of the temporary setting. A computer program described in 1. A flow velocity distribution database creation procedure for associating the flow velocity distribution data calculated by the flow velocity distribution / flow velocity calculation means with the average flow velocity calculated by the average flow velocity calculation means and accumulating in the flow velocity distribution database;
From the flow velocity distribution database, the flow rate distribution data corresponding to the predetermined average flow velocity data is extracted to calculate the flow velocity distribution or flow rate of the fluid to be measured. The computer program according to claim 11.

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