KR20190001506A - Electronic Flow Meter and The Measurement Error Correcting Methode - Google Patents

Abstract

In a flow meter, characteristic of an error in accordance with a change in a flow rate per hour is not linear as shown in Fig. 1, so a method of performing connector by proper division of a flow rate section is selected. To perform the correction by the proper division of the flow rate section should pass through a correction test, such that measurement quality is improved as the number of correction segments is increased, but the number of the correction test is increased, thereby an efficient correction test method is required. Moreover, a measurement coefficient detected through a correction test of a predetermined number of reference samples is integrally applied to a manufactured product, a lot of products are out of an error margin due to a device difference of each flow meter, and such product should pass a correction procedure through a retest, such that productivity degradation is large. Accordingly, disclosed are an electronic flow meter having a correction function, which uses programming and communication functions of a micro control unit (MCU) of an electronic flow meter to detect and apply a measurement coefficient corrected by reflecting each device difference to each flow meter by one or two tests per section, and a correction method thereof. According to the present invention, the method comprises a step a flowing step and a flow rate information receiving step.

Description

 BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electronic flow meter,

The present invention has a function of measuring the flow rate by integrating the flow rate per revolution of the impeller (hereinafter referred to as a measurement factor) by the number of revolutions of the impeller when the impeller is rotated with the impeller rotating by a fluid flowing in a constant channel in the flow meter, The flow rate of the impeller in the flow meter is not linearly proportional to the change in the speed of the fluid flowing in the pipe, Measuring error of the flow rate caused by the deviation caused by the deviation and the difference in the number of revolutions of the impeller caused by the mechanical difference of the internal structure of each flowmeter, that is, by the train (instrument difference) A more efficient and accurate method of calibrating the measurement factor in a flow meter that adopts a method of calibrating the flow rate value In order to improve the productivity of the product and to improve the quality of the product, the deviation of the impeller rotation speed according to the flow velocity is divided into a plurality of flow velocity sections, and a measurement coefficient corresponding to each of the flow velocity sections is divided. An electronic flow meter that improves the productivity and measurement quality of a product by obtaining an accurate measurement coefficient of the flow meter at each flow point without any deviation by each train by measuring and applying the direct measurement coefficients by interval, .

As the most common flow meter to which the present invention is applied, there is a household flow meter such as a flow meter of a water meter, a meter of a hot water meter, and the like. The calibration method of the flowmeter and the development status of the flowmeter have been developed passively according to the change of the calibration standard established by the national institution. In the electronic flowmeter, if the mechanical structure of the flowmeter is separately measured, Since the correction process of errors takes a large part in the production process of the product, an efficient correction method is required.

 FIG. 1 is a graph showing an error between a supply flow rate and a measured flow rate due to a change in flow rate (l / h) (X axis) per hour of a fluid flowing through a flow meter As a graph of the error rate characteristic of a general flow meter showing the percentage (Y axis), it shows an error rate characteristic graph of a flow meter in which a measurement number is corrected at a flow rate (l / h) have.

Fig. 2 shows a flow meter in which the flow rate per hour is divided by 3 (11,12,13), the specific point of the flow rate per hour (20 21 22) is corrected and the calibrated measurement coefficients (30, 31, 32) The error rate characteristic graph is shown.

It can be seen that the error rate (40, 42, 42) between the supplied flow rate and the measured flow rate at the specific flow rate (l / h) points 20, 21, 22 of the flow meter having the error rate characteristic of FIG.

In a calibration test for finding the measurement coefficients (30, 31, 32) at the flow rate (l / h) points (20, 21, 22)

Step 1: First, a plurality of samples are selected and a constant test flow rate is passed to the flow meter at the flow rate (l / h) per hour of 20, 21, and 22 and the correction factor at each point is calculated. 31, 32).

Knowing the feed rate (N), the measured flow value (M), the impeller rotation speed (R), the set measurement factor (P) and the corrected measurement factor (P ' '= N / R can be directly obtained. However, since the number of revolutions of the impeller is an internal variable used in the program of the electronic flow meter, the tester can not know. Thus, using the measured flow rate value that appears in the measurement result displayed on the indicator, a correction value of the measurement coefficient is obtained as P '= N / M * P

Step 2: The product is produced by reflecting the measurement coefficients (30, 31, 32) obtained in Step 1 in the program. The produced product is subjected to a correction test by selecting one flow rate point (22) per hour and correcting the measurement coefficient (32) by obtaining the correction rate of the error, and applying the correction rate to 30 and 31, .

Step 3: In each section of the calibrated flowmeter, find the flowmeter that has the section where the excessive error occurs through the flowmeter test, and perform the re-calibration test to correct it.

The electronic flowmeter has a flow rate sensor and an LCD display to indicate the flow rate. It has a communication function with the outside, so that the measured value can be transmitted to the outside to enable remote meter reading. In normal flow meter operation mode, the information that the tester knows is only the value of the supply flow rate that feeds the flowmeter to the flow meter and the measured flow rate after the flow is displayed on the LCD window. The flow meter itself is complicated by the fact that it must be tested by changing the operation mode of each individual flow meter by changing the mode selection switch to the hardware for the feedback correction method or calibration test to check and re- This is because the function and information depend on the test method.

According to the present invention, in the electronic flow meter for performing the interval correction as described above, the setting of various test modes and the constant test flow rate are provided in the interval correction method, the measured values appearing on the meter are checked and corrected, By providing a technology that can calculate and apply the accurate measurement coefficient of the test section by one test without complicated calibration process which is corrected again through the feedback of the result, it is possible to improve the productivity of the product and increase the measurement quality of the flow meter, Using the inventive technique, we suggest ways to automate the entire calibration test process.

 As a technical solution to achieve the object of the present invention,

  Operation of flow sensor, flow rate value display and data communication function are connected with intelligent electronic flowmeter, electronic flowmeter and serial communication line which are processed by the program embedded in MCU and MCU. A hand terminal connected to the mobile terminal is presented. The interlocking hand terminal provides the test flow information to the flowmeter that the electronic flowmeter should know in order to directly calculate the measurement coefficient during the calibration test and perform the function such as checking the result or read the basic data related to the calibration from the flowmeter, And provides the function of calculating the correction coefficient and providing it to the flow meter. The test flow information is information about the flow rate value or flow rate section that passed the test to the flow meter.

4, a hand terminal 203, which is connected to the electronic flow meters 100, 101, ... N by a communication line 204 and is capable of exchanging information with the electronic flow meter by a predetermined protocol, A fluid supply device 200 having a flow regulation function 201 and a fluid pipe opening / closing function 202 is required. The hand terminal 203 shares information such as flow rate section information of the correction target flowmeter, the supply flow rate, the measurement flow rate, the number of revolutions of the impeller, and the measurement coefficient through the flowmeter and the communication line And provided with a function to control the flow rate regulating function 201 per hour of the test apparatus and the fluid channel opening / closing function 202, or a flow meter and a communication connection module It is a device that can be programmed such as a general computer, a notebook computer and the like.

The present invention simplifies the test procedure for error correction of flow measurement values of an electronic flow meter, thereby enhancing the productivity of the product and correcting the error more accurately. Thus, it is possible to improve the flow measurement quality of the flow meter, And provides techniques that can be applied to the automation of

1 shows a graph of the error rate characteristic of the result of applying the measurement coefficient 32 corrected at the correction point 22 of the flow rate per hour (l / h) to the flow rate measurement of the whole flow rate section.
2 is a graph showing the error rate characteristics of the results of applying the measurement coefficients 30 and 31 further corrected at one point 20 and 21 of the flow rate per hour (l / h) to the constant interval 11 and 12 including the correction point, Show.
FIG. 3 shows the results of FIG. 2, in which the measurement coefficients 33 and 34 are obtained at one point 23 and 24 of the flow rate per hour (l / h), and the two points 20, The equation of the straight line 52 is obtained by the straight line 50 and the coordinates 23 and 33 21 and 31 and the straight line 51 and the coordinates 24 and 34 and 22 and 32 in the flow rate The measurement coefficient outside the calibration point shows a graph of the error rate characteristic of the result obtained by linearly correcting the measurement coefficient in this linear equation.
Fig. 4 is a configuration diagram of a test equipment required for testing the flowmeter of the present invention.
5 is a flow chart showing the procedure of the calibration test of the product meter of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. An ideal flow meter is one in which the measured value of the supply flow is measured with the inherent measuring means and the displayed value should be the same as the supplied flow rate. N = R * P when the flow rate (N), flow rate (M), number of rotations of the impeller (R), and number of rotations per unit of rotation (P) The measured coefficient is calculated as P = N / R, which is an accurate measured coefficient, not a correction target. The flow rate including the one-point correction point of the flow rate per hour is divided by one or more, I would like to suggest ways to save.

Flow rate section (l / h)      a1       a2         a3 ~~         moment Test flow (ℓ) N1 N2 N3 ~~ Nn Revolutions R1 R2 R3 ~~ Rn Measurement factor (ℓ) P1 P2 P3 ~~ Pn

As shown in the above table, if we divide the interval of the flow rate per hour into n and calculate the calibration coefficient in each interval, based on the flowchart in Fig. 5, The value is obtained from the test sample and is not referenced in the calibration test. Measurement initialization is the measurement value displayed on the display of the flowmeter = 0 The state of the impeller rotation number = 0 which is an internal variable of the flowmeter. In the hand terminal, the flow rate information according to the calibration test scenario and the test flow rate supplied from one measurement point within the interval are set. 50. After the product is manufactured and the initialized flowmeter is ready for testing, the test flow rate (N1) corresponding to the flow rate section (a1) per hour is passed through the test apparatus. 51 The flowmeter detects the number of rotations of the impeller (R1) with respect to the flow rate.

52. Provide flow information to the flow meter for the calculation of the measurement factor at the hand terminal.

(Here, the flow information provided by the hand terminal is either the test flow value (N1) and the flow range (a1), or the test flow value is always constant in a constant flow range and the test flow value (N1) is set to a fixed value in the built- In this case, it may be the flow rate section a1.

53. The flowmeter calculates and stores the measurement factor P1 (= N1 / R1) to obtain a measurement factor P1 corresponding to the flow rate section a1 for a certain time.

 54. Perform measurement initialization in the hand terminal for the next interval test

The process of 51 and 53 is processed automatically by the processor of the flow meter, so the tester does not have to consider this step.

The test is completed by repeating the set flow point to obtain the measurement coefficient. The test flow point to obtain the measurement factor can be one or two within a flow range and the measurement factor obtained at the flow range boundary point can be shared in both sections.

 In the above test, one measurement coefficient is obtained in one interval, and the error rate characteristic curve of the flow meter using the measurement coefficient for each flow interval is shown in FIG.

As can be seen in FIG. 2, the error rate of the measured flow point is corrected to zero, but it can be seen that the correction of the error rate is unsatisfactory at the flow rate outside the correction point according to the error rate characteristic. A further subdivision of the calibration interval may result in a higher level of calibration, but if the interval is too large, the number of calibration tests may increase, which may hinder productivity.

Here, it is possible to derive a linear equation by measuring the measurement coefficient at another point in the flow rate section, that is, by using the two flow points in one flow section and the measurement factors at that point. In the flow points belonging to the section, 1 and 2, the measurement coefficients 33 and 34 are obtained at one point 23 and 24 of the flow rate per hour (l / h), and the flow rate points (20,30) (23,33) consisting of two measurement points made up of a straight line (50), coordinates (23,33) (21,31) 52 shows the graph of the error rate characteristic of the result obtained by linearly correcting the measurement coefficient in the linear equation by using the measurement coefficient outside the correction point within the flow rate (l / h) per hour. The choice of two flow points in the section for linear correction is either the section point or the point within the section depending on the nature of the error rate, or the flow point selected to reduce the flow section and increase the error correction factor.

In addition, if there is one measurement range in one flow range in the above process, the correction of the interval is corrected to one measurement factor, and if there are two measurement ranges in one flow range, an optional method of performing linear correction . This is selected depending on the nature of the error rate that appears in the whole of the flow rate per hour of the calibrated flowmeter, and the selection of the calibration method is automatically processed by the built-in program of the flow meter according to the number of measured measurement factors present in one flow period.

In order to perform the calibration test, a flow supply device 200 having an electronic control function such as a supply flow rate adjusting function 201 and a fluid channel opening / closing function 202 is configured as a test facility and a series of test scenarios To implement the function of controlling the supply flow rate regulation function 201 and the fluid channel opening / closing function 202 of the flow rate supply device and connecting one or more correction target flow rates to easily implement batch automation for all steps of the calibration test I can see that it is possible.

20,21,22, 23,24 Point of flow (l / h) per hour selected for calibration test
30,31,32 Measurement factor at the flow compensation point (flow rate per impeller (l))
40, 41, 42 Measurement error rate
50,51,52 A straight line formed by two flow points and measurement coefficients in the flow section
11,12,13 Flow rate per hour for which the number of measurement is applied
200 Test Flow Supply
201 hour supply flow adjustment function
202 Fluid line open / close function
100,101, .... N Calibration target flowmeter
203 Hand terminal (computer device connected with flow meter and serial communication method)
204 Serial communication line between hand terminal and flow meter
X Flow rate per hour (l / h) (X axis)
Y Percentage of error between supply flow and measured flow (Y axis)

Claims (5)

An electronic flow meter operated by a built-in program that measures the flow rate by integrating the number of revolutions of the rotating impeller and the unit flow rate value per revolution according to the flow of the supplied fluid. The flow rate is divided into one or more And measuring the actual measurement coefficient at a certain flow rate point within each flow rate section, the flow rate information about the flow rate of the impeller about the flow rate is transmitted to the flow rate meter as a test flow rate at the flow rate point corresponding to the flow rate point, And the flow rate is measured by correcting the error according to the interval based on the actual measurement coefficient obtained at the test flow point.
Method for correcting the interval coefficient according to claim 1 The actual measurement coefficient is obtained at one flow point belonging to one or more flow velocity sections and used for the flow rate measurement of the corresponding section to correct the error as shown in Fig. Processor-based electronic flowmeter that measures flow rate.
The method according to claim 1, wherein the method comprises the steps of: selecting two flow points that can include a boundary point within one or more flow regions and measuring measured values at the flow points (flow rate, The measurement coefficient obtained by the change of the flow rate in the corresponding section is obtained by using the equation of the straight line formed by the coordinates of the two points made of the coordinates Flow meter.
The method according to claim 1, wherein the step of correcting the measurement coefficient of each section comprises the step of correcting the error by dividing the second or third item according to the characteristic of the error rate of each section in the section- Measuring processor based electronic flowmeter.
In an electronic flowmeter operated by a built-in program that measures the flow rate by integrating the number of revolutions of the rotating impeller and the unit flow rate value per revolution according to the flow of the supplied fluid, a constant flow rate of the flow rate divided into one or more For the test to obtain the actual measurement coefficient at the point, set the flow supply device to the purpose of the test and connect one or more flowmeters to be tested to the hand terminal and the communication line as shown in Fig. 4
1) passing the constant supply flow rate to the flow meter at the flow velocity of the flow velocity section to be corrected
2) The flowmeter receives the flow rate information about the supplied flow rate from the hand terminal connected to the communication line and calculates the actual measurement coefficient of the flow rate point.

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