KR102603818B1 - Flow rate correction method according to the water level of the conduit flow metering system - Google Patents

Abstract

The present invention relates to a conduit flow measurement system, and more specifically, to a flow rate correction method according to the water level of the conduit flow measurement system. For this purpose, in the flow rate correction method using the flow meter 100 installed in the conduit 10 and the pressure sensor 200 to measure the water level, the flow meter 100 measures the flow rate (S100), and the pressure sensor 200 Measuring pressure (S110); The pressure signal processing unit 250 calculates the water level based on the pressure (S120); The control unit 300 calculates the flow rate of the conduit 10 based on the flow rate and water level (S130); The control unit 300 calculates a corrected flow rate by applying a predetermined correction coefficient to the flow rate in response to the water level (S140); The control unit 300 calculates the average flow rate by excluding the maximum and minimum values among the corrected flow rates (S150); and a step (S160) in which the control unit 300 outputs the average flow rate. A flow rate correction method according to the water level of the conduit flow measurement system is provided.

Description

Flow rate correction method according to the water level of the conduit flow metering system}

The present invention relates to a conduit flow measurement system, and more specifically, to a flow rate correction method according to the water level of the conduit flow measurement system.

Generally, a method of measuring the sewage flow rate in a sewer pipe includes using an electro-magnetic flowmeter; A method of calculating flow rate using devices that measure point flow velocity at one point or several points of the same flow cross section within a sewer pipe; A method of measuring flow rate by installing a weir and flume in a sewer pipe; A method of calculating flow rate by installing an aperture device in a sewer pipe and measuring the differential pressure generated there; A method of calculating flow rate by combining an ultrasonic time difference flowmeter and a water level sensor; Flow measurement methods were used, such as the ultrasonic multi-line method, which calculates the flow rate by installing several ultrasonic time difference flow sensors on the outer wall of the sewer pipe and a separate measurement pipe and calculating the flow rate by averaging their flow velocities. Among these, the method of measuring sewage flow rate by combining ultrasonic water level gauges and other water level measurement methods and ultrasonic Doppler flow velocity sensors at the bottom of sewer pipes was the most widely used.

More specifically, an ultrasonic Doppler flowmeter is used to measure the flow rate of liquid (e.g. water, sewage, sewage, rainwater, etc.) flowing in the conduit. In particular, in non-obese pipes with a water level in the conduit (liquid only partially In the case of the filled) type, the water level is measured with a separate pressure sensor and then the flow rate is measured using the pipe diameter and water level.

However, due to the nature of the pressure sensor, immersion type flow meters have a dead zone where the water level cannot be measured, and in the case of non-invasive pipes, waves occur at the water level of the flowing water. For this reason, it is difficult to measure the exact flow rate. Therefore, a technology that can measure the accurate flow rate of liquid flowing through a conduit in real time is needed.

1. Japanese Patent Publication No. 1997-229734 (ultrasonic Doppler flowmeter), 2. Japanese Patent Publication No. 2020-118660 (Method for measuring water movement by ultrasonic waves), 3. Republic of Korea Patent Registration No. 10-1753891 (Control device and control method for drain inlet valve and parallel operation pump).

Therefore, the present invention was created to solve the above problems, and the problem to be solved by the present invention is to adjust the water level of the conduit flow measurement system that can measure the accurate flow rate by correcting the flow rate according to the water level of the pipe. It provides a flow rate correction method.

Another object of the present invention is to provide a flow rate correction method according to the water level of a conduit flow measurement system that can calculate a reliable average flow rate even if there is a large difference between the maximum flow rate and the minimum flow rate.

However, the technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly apparent to those skilled in the art from the description below. It will be understandable.

In order to achieve the above technical problem, in the flow rate correction method using the flow meter 100 installed in the conduit 10 and the pressure sensor 200 to measure the water level, the flow meter 100 measures the flow rate (S100), A step in which the pressure sensor 200 measures pressure (S110); The pressure signal processing unit 250 calculates the water level based on the pressure (S120); The control unit 300 calculates the flow rate of the conduit 10 based on the flow rate and water level (S130); The control unit 300 calculates a corrected flow rate by applying a predetermined correction coefficient to the flow rate in response to the water level (S140); The control unit 300 calculates the average flow rate by excluding the maximum and minimum values among the corrected flow rates (S150); and a step (S160) in which the control unit 300 outputs the average flow rate. A flow rate correction method according to the water level of the conduit flow measurement system is provided.

Additionally, the conduit 10 is a non-fat conduit.

In addition, the measurement steps (S100, S110) to the average flow rate calculation step (S150) are repeated at regular intervals, and the constant time is determined in the range of 5 seconds to 3 minutes.

In addition, the average flow rate calculation step (S150) excludes the maximum and minimum values during a certain period of time.

Additionally, the flow rate calculation step (S130) uses the input diameter of the conduit (10).

Additionally, the correction coefficient is 0.98 when the water level is 0.095 m or less, 1 when the water level is 0.096 to 0.15 m, and 1.03 when the water level is greater than 0.15 m.

Additionally, in the correction flow rate calculation step (S140), the correction flow rate is calculated by multiplying the flow rate by the correction coefficient.

Additionally, the velocity meter 100 is an ultrasonic Doppler type velocity meter.

According to one embodiment of the present invention, the accurate flow rate can be measured by correcting the flow rate according to the water level in the pipe. Therefore, even if the flow rate affected by the water level is measured using the ultrasonic Doppler method, accurate measurement is possible by correcting the flow rate. Additionally, errors in flow rate measurement may occur depending on the installation location of the flow meter. By correcting these measurement errors, accurate flow rate calculation is possible.

In addition, when there is a large difference between the maximum flow rate and the minimum flow rate, reliability was greatly reduced because the average flow rate was calculated by including all these values. However, according to an embodiment of the present invention, a more reliable and accurate flow rate can be obtained by excluding the maximum and minimum flow rates from the average calculation.

However, the effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned above will be clearly understood by those skilled in the art from the description below. You will be able to.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described later. Therefore, the present invention includes the matters described in such drawings. It should not be interpreted as limited to only .
1 is a schematic block diagram of a conduit flow measurement system;
Figure 2 is a flow chart showing a flow rate correction method according to the water level of the conduit flow measurement system according to an embodiment of the present invention.

Below, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, since the description of the present invention is only an example for structural or functional explanation, the scope of the present invention should not be construed as limited by the examples described in the text. In other words, since the embodiments can be modified in various ways and can have various forms, the scope of rights of the present invention should be understood to include equivalents that can realize the technical idea. In addition, the purpose or effect presented in the present invention does not mean that a specific embodiment must include all or only such effects, so the scope of the present invention should not be understood as limited thereby.

The meaning of terms described in the present invention should be understood as follows.

Terms such as “first” and “second” are used to distinguish one component from another component, and the scope of rights should not be limited by these terms. For example, a first component may be named a second component, and similarly, the second component may also be named a first component. When a component is referred to as being “connected” to another component, it should be understood that it may be directly connected to the other component, but that other components may also exist in between. On the other hand, when a component is referred to as being “directly connected” to another component, it should be understood that there are no other components in between. Meanwhile, other expressions that describe the relationship between components, such as "between" and "immediately between" or "neighboring" and "directly neighboring" should be interpreted similarly.

Singular expressions should be understood to include plural expressions, unless the context clearly indicates otherwise, and terms such as “comprise” or “have” refer to the specified features, numbers, steps, operations, components, parts, or them. It is intended to specify the existence of a combination, and should be understood as not excluding in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

All terms used herein, unless otherwise defined, have the same meaning as commonly understood by a person of ordinary skill in the field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as consistent with the meaning they have in the context of the related technology, and cannot be interpreted as having an ideal or excessively formal meaning unless clearly defined in the present invention.

Configuration of the Example

Hereinafter, the configuration of the preferred embodiment will be described in detail with reference to the attached drawings. Figure 1 is a schematic block diagram of a conduit flow measurement system. As shown in FIG. 1, the conduit 10 may be a pipe forming a closed cross-section.

The liquid flowing in the conduit 10 is typically constant.

The conduit (10) may be full, but in the case of an empty pipe, there is a water level (20) within the conduit (10), and the water level (20) is expressed as the height (H) from the floor.

The flow meter 100 is installed on both sides of the bottom or near the bottom of the conduit 10 and transmits ultrasonic waves 120 to the flowing liquid. The flow meter 100 can measure the flow velocity (v) by applying the formula of the Doppler effect to the received ultrasonic waves.

The flow speed signal processing unit 150 receives the signal from the flow meter 100 and outputs digitized flow speed (V) information. To this end, the flow rate signal processing unit 150 includes an ultrasonic oscillation circuit, an amplification circuit, a filter, an analog-to-digital conversion circuit, etc. The flow rate signal processing unit 150 is connected to the control unit 300.

The pressure sensor 200 is an immersion type sensor and is installed on the bottom of the conduit 10 to output a pressure proportional to the water pressure as an output signal. Sensors for measuring the water level include ultrasonic water level measurement sensors and radar-type water level measurement sensors in addition to the pressure sensor 200 using water pressure, and various types of water level measurement sensors can replace the pressure sensor 200 of the present invention. there is.

The pressure signal processing unit 250 outputs digitized water level (H) information in proportion to the compressed signal by water pressure. For this purpose, the pressure signal processing unit 150 includes an amplifier circuit, a filter, an analog-to-digital conversion circuit, etc. The pressure signal processing unit 150 is connected to the control unit 300.

The control unit 300 calculates the flow rate using the flow rate (v) input from the flow signal processing unit 150, the water level (H) input from the pressure signal processing unit 250, and the diameter information of the conduit 10 input in advance. . That is, the control unit 300 obtains the cross-sectional area of the liquid from the water level (H) and the diameter, and calculates the flow rate using the flow velocity (v). The control unit 300 may be a microcomputer, CPU, laptop, or computer.

Operation of the Embodiment

Hereinafter, the operation of the preferred embodiment will be described in detail with reference to the attached drawings. Figure 2 is a flow chart showing a flow rate correction method according to the water level of the conduit flow measurement system according to an embodiment of the present invention. As shown in FIG. 2, first, the flow meter 100 measures the flow rate (S100), and the pressure sensor 200 measures the pressure (S110). Specifically, the flow meter 100 irradiates ultrasonic waves 120 and receives the reflected ultrasonic waves 120, and the flow speed signal processing unit 150 calculates the flow speed (v) information and outputs it to the control unit 300. At the same time, the pressure sensor 200 measures pressure.

Next, the pressure signal processing unit 250 converts the measured pressure into digitized water level (H) information (S120).

Next, the control unit 300 receives the flow rate (v) and the water level (H), and calculates the flow rate using the diameter of the conduit 10 input in advance (S130). The control unit 300 obtains the cross-sectional area of the liquid from the water level (H) and diameter, and calculates the flow rate using the flow velocity (v). This flow rate is calculated every certain time (e.g. 5 seconds). The schedule time is determined in the range of 5 seconds to 3 minutes. If it is too frequent, it will overload the calculation processing and cause delays, and if it is too long, there will be a problem of not being able to respond to changes in flow rate.

Next, the control unit 300 calculates the corrected flow rate by multiplying the flow rate by a predetermined correction coefficient corresponding to the water level (H) (S140). The correction coefficient is 0.98 when the water level (H) is 0.095 m or less, 1 when the water level (H) is 0.096 to 0.15 m, and 1.03 when the water level (H) is greater than 0.15 m. The correction coefficient can be applied proportionally to pipes 10 having different diameters.

Next, the control unit 300 groups a plurality of corrected flow rates calculated at intervals of 1 minute (e.g., 5 seconds) into groups, and calculates the average flow rate using the remaining flow rate information excluding the maximum and minimum flow rates within the group. Do it (S150). The reason for excluding the maximum flow rate and minimum flow rate is that, firstly, the flow rate (v) or water level (H) within the pipe 10 may produce results significantly different from the current flow rate due to an instantaneous measurement error. Second, if the deviation between the maximum and minimum flow rates is large, the reliability of the average flow rate decreases.

Next, the control unit 300 stores and outputs the average flow rate (S160). Output includes displaying it on the display within the device or transmitting it to an external device (e.g., a server computer in a central control center) through wired or wireless communication. This output can be done in 1-minute increments.

Experiment example

Hereinafter, the experiment and experimental data of the flow rate correction method according to the water level of the conduit flow measurement system according to the present invention will be described.

Experiment example

hour Standard flow rate
(m ³ /h) Water level
(m) flow rate
(m/sec) Flow rate before correction
(m ³ /h) correction coefficient Calibrated flow rate
(m/sec) Calibrated flow rate
(m ³ /h) 01-06 13:30 15 0.09 0.235 15.46 0.98 0.23 15.195 01-06 13:30 0.09 0.232 15.256 0.227 14.924 01-06 13:30 0.09 0.231 15.19 0.226 14.943 01-06 13:30 0.09 0.234 15.388 0.229 14.969 01-06 13:31 0.09 0.234 15.394 0.229 15.018 01-06 13:31 0.09 0.235 15.453 0.23 15.109 01-06 13:31 0.09 0.238 15.651 0.233 15.234 01-06 13:31 0.091 0.233 15.559 0.228 15.129 01-06 13:32 0.091 0.237 15.826 0.232 15.413 01-06 13:32 0.09 0.236 15.519 0.231 15.217 average flow rate 15.470 average flow rate 15.115

[Table 1] shows the results of measuring the water level and flow rate at 15-second intervals for a standard flow rate of 15 m ³ /h and then multiplying the correction coefficient to calculate the corrected flow rate. [Table 1] and the following experiments were accurately measured using a reference device (electromagnetic flowmeter) with guaranteed traceability in the laboratory of a national calibration institute. [Table 1] shows that the average flow rate before correction was 15.47 m ³ /h, which was 4.7% higher than the standard flow rate (for reference, the allowable flow rate error is ±2%). Accordingly, the correction coefficient was adjusted by -2% (0.98) to fall within the acceptable range. In other words, the flow rate of 15.115 m ³ /h corrected by multiplying the correction coefficient falls within the allowable error range.

hour Standard flow rate
(m ³ /h) Water level
(m) flow rate
(m/sec) Flow rate before correction
(m ³ /h) correction coefficient Calibrated flow rate
(m/sec) Calibrated flow rate
(m ³ /h) 01-06 13:35 20.1 0.099 0.271 20.399 One 0.271 20.399 01-06 13:35 0.099 0.270 20.304 0.27 20.304 01-06 13:35 0.099 0.267 20.074 0.267 20.074 01-06 13:35 0.099 0.270 20.177 0.27 20.177 01-06 13:36 0.099 0.270 20.239 0.27 20.239 01-06 13:36 0.099 0.270 20.201 0.27 20.201 01-06 13:36 0.099 0.271 20.398 0.271 20.398 01-06 13:36 0.099 0.270 20.328 0.27 20.328 01-06 13:37 0.099 0.262 19.648 0.262 19.648 01-06 13:37 0.1 0.266 20.114 0.266 20.114 average flow rate 20.188 average flow rate 20.188

[Table 2] shows the results of measuring the water level and flow rate at 15 second intervals for a standard flow rate of 20.1 m ³ /h and then multiplying the correction coefficient to calculate the corrected flow rate. [Table 2] shows that the average flow rate before correction is 20.188 m ³ /h, which falls within the allowable flow rate error (±2%) range. Therefore, no correction is necessary.

hour Standard flow rate
(m ³ /h) Water level
(m) flow rate
(m/sec) Flow rate before correction
(m ³ /h) correction coefficient Calibrated flow rate
(m/sec) Calibrated flow rate
(m ³ /h) 01-06 13:40 25.3 0.108 0.293 24.777 1.03 0.302 25.422 01-06 13:40 0.108 0.296 25.031 0.305 25.708 01-06 13:40 0.107 0.293 24.465 0.302 25.363 01-06 13:40 0.108 0.294 24.862 0.303 25.557 01-06 13:41 0.108 0.292 24.693 0.301 25.466 01-06 13:41 0.107 0.294 24.557 0.303 25.404 01-06 13:41 0.107 0.294 24.598 0.303 25.39 01-06 13:41 0.107 0.291 24.298 0.300 25.164 01-06 13:42 0.107 0.298 24.882 0.307 25.741 01-06 13:42 0.107 0.290 24.214 0.299 25.091 average flow rate 24.638 average flow rate 25.431

[Table 3] shows the results of measuring the water level and flow rate at 15-second intervals for a standard flow rate of 25.3 m ³ /h and then multiplying the correction coefficient to calculate the corrected flow rate. [Table 3] shows that the average flow rate before correction was 24.638 m ³ /h, which was 6.62% lower than the standard flow rate. Accordingly, a correction coefficient of +3% (1.03) was corrected to bring it within the acceptable range. In other words, the flow rate of 25.431 m ³ /h corrected by multiplying the correction coefficient falls within the allowable error range.

Flow correction water level section correction coefficient 0.001~0.095(m) 0.98 0.096~0.15(m) One 0.16~(m) 1.03

[Table 4] is a table showing correction coefficients for each water level range in the experiments of [Table 1] to [Table 3] described above.

No hour Standard flow rate
(m ³ /h) Measured flow rate
(m ³ /h) Standard flow rate
average (m ³ /h) moving average Maximum and minimum applicable
moving average apply
data average flow rate
(m ³ /h) average deviation
(%) average flow rate
(m ³ /h) average deviation
(%) One 01-06 14:56 15.001 14.956 2 01-06 14:56 14.998 14.807 3 01-06 14:56 15.101 13.522 4 01-06 14:56 14.999 14.945 5 01-06 14:56 14.568 14.765 6 01-06 14:56 15 15.006 7 01-06 14:56 14.998 14.955 8 01-06 14:56 14.9 14.806 9 01-06 14:56 14.877 14.740 10 01-06 14:56 15.21 21.520 14.965 15.402 2.92 14.873 -0.62 No 1~10 11 01-06 14:57 15.121 15.218 14.977 15.428 3.01 14.905 -0.48 No. 2~11 12 01-06 14:57 15.001 15.039 14.978 15.452 3.17 14.934 -0.29 No. 3~12 13 01-06 14:57 14.885 14.819 14.956 15.581 4.18 14.944 -0.08 No. 4~13 14 01-06 14:57 15.002 15.012 14.956 15.588 4.22 14.953 -0.02 No. 5~14 15 01-06 14:57 15.01 15.083 15.000 15.620 4.13 14.992 -0.05 No 6~15 16 01-06 14:57 14.82 14.772 14.982 15.596 4.10 14.963 -0.13 No. 7~16 17 01-06 14:57 15.011 14.958 14.984 15.597 4.09 14.963 -0.14 No. 8~17 18 01-06 14:57 15.16 15.102 15.010 15.626 4.11 15.000 -0.06 No. 9~18 19 01-06 14:57 15.3 15.086 15.052 15.661 4.05 15.040 -0.08 No. 10~19 20 01-06 14:57 15.095 15.108 15.041 15.020 -0.14 15.026 -0.10 No. 11~20

[Table 5] calculates the average flow rate by shifting 10 pieces of data one by one for the flow rate measured at 6-second intervals. In [Table 5], the minimum value of the measured flow rate is 13.522 m ³ /h and the maximum value is 21.520 m ³ /h. Therefore, it can be seen that if the average flow rate is calculated including these maximum and minimum values, an error of 3 to 4% occurs, and if the average flow rate is calculated using 8 data excluding the maximum and minimum values, the measurement error can be reduced to within 1%. It was confirmed that it was possible.

A detailed description of preferred embodiments of the invention disclosed above is provided to enable any person skilled in the art to make or practice the invention. Although the present invention has been described above with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the scope of the present invention. For example, a person skilled in the art may use each configuration described in the above-described embodiments by combining them with each other. Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The present invention may be embodied in other specific forms without departing from the spirit and essential features of the present invention. Accordingly, the above detailed description should not be construed as restrictive in all respects and should be considered illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention. The present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, claims that do not have an explicit reference relationship in the patent claims can be combined to form an embodiment or included as a new claim through amendment after filing.

10: conduit,
20: water level,
100: tachometer,
120: ultrasound,
150: flow rate signal processing unit,
200: pressure sensor,
250: pressure signal processing unit,
300: control unit,
H: water level,
V: Flow velocity.

Claims (8)

In the flow correction method using the flow meter 100 installed in the conduit 10 and the pressure sensor 200 to measure the water level,
The flow meter 100 measures the flow rate (S100) and the pressure sensor 200 measures the pressure (S110);
The pressure signal processing unit 250 calculates the water level based on the pressure (S120);
The control unit 300 calculates the flow rate of the conduit 10 based on the flow rate, the water level, and the input diameter of the conduit 10 (S130);
The control unit 300 calculates a corrected flow rate by multiplying the flow rate by a predetermined correction coefficient corresponding to the water level (S140);
The control unit 300 calculates an average flow rate excluding the maximum value of the correction flow rate and the minimum value of the correction flow rate during a certain period of time (S150); and
It includes a step (S160) of the control unit 300 outputting the average flow rate,
The measurement steps (S100, S110) to the average flow rate calculation step (S150) are repeated at the predetermined time,
The schedule time is 5 seconds to 3 minutes,
The conduit (10) is a fat pipe,
The velocimeter 100 is an ultrasonic Doppler type velocimeter,
The correction coefficient is 0.98 when the water level is 0.095 m or less, 1 when the water level is 0.096 to 0.15 m, and 1.03 when the water level is greater than 0.15 m. Flow rate according to the water level of the conduit flow measurement system. Correction method. delete delete delete delete delete delete delete

Images