Method for setting zero of electromagnetic flowmeter, measuring device and system

Abstract

This invention discloses a method, measuring device, and system for calibrating and setting the zero point of an electromagnetic flowmeter. The method includes: measuring the first average flow velocity value of the electromagnetic flowmeter under test in a full-pipe static state within a first preset time period and saving the obtained initial zero-point flow velocity removal value to the electromagnetic flowmeter under test; running a water flow of a first preset flow rate and measuring the measured average flow rate value of the electromagnetic flowmeter under test and the standard average flow rate value of a standard electromagnetic flowmeter within a second preset time period to calculate a sensor coefficient and save it to the electromagnetic flowmeter under test; running a water flow of a second preset flow rate and measuring the average flow rate error between the standard electromagnetic flowmeter and the electromagnetic flowmeter under test within a third preset time period, and measuring the second average flow velocity value of the electromagnetic flowmeter under test; calculating the final zero-point flow velocity removal value and saving it to the electromagnetic flowmeter under test. This invention can meet the measurement accuracy requirements and improve the measurement accuracy of electromagnetic flowmeters.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic flowmeter technology, and in particular to a method, measuring device and system for calibrating and setting the zero point of an electromagnetic flowmeter. Background Technology

[0002] Electromagnetic flow meters are widely used as flow measurement devices. They require high accuracy, currently generally around 0.5%. However, current electromagnetic flow meters are calibrated using flow calibration equipment, where zero-point calibration is typically a single-step process; once the sensor coefficients are calibrated, the calibration is complete. While this calibration may achieve the required accuracy for high-speed flow, it results in significant errors for low-speed flow, sometimes exceeding the accuracy requirements. This leads to lower accuracy at small flow rates, ultimately reducing the overall measurement accuracy of the electromagnetic flow meter. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method, measuring device and system for calibrating and setting the zero point of an electromagnetic flowmeter, which can achieve accurate measurement error of electromagnetic flowmeter for small flow and large flow, meet the measurement accuracy requirements and improve the measurement accuracy of electromagnetic flowmeter.

[0004] To address the aforementioned technical problems, this invention provides a method for calibrating and setting the zero point of an electromagnetic flowmeter, comprising: placing the measuring tube of the electromagnetic flowmeter under test in a full-pipe static water state; measuring the first average flow velocity value of the electromagnetic flowmeter under test within a first preset time period to obtain an initial zero-point flow velocity removal value, and saving the initial zero-point flow velocity removal value to the electromagnetic flowmeter under test; introducing a first preset flow rate of water into the measuring tubes of the electromagnetic flowmeter under test and a standard electromagnetic flowmeter, and respectively measuring the measured average flow rate value of the electromagnetic flowmeter under test and the standard average flow rate value of the standard electromagnetic flowmeter within a second preset time period. The sensor coefficient is calculated using the measured average flow rate and the standard average flow rate, and then saved to the electromagnetic flow meter under test. A second preset flow rate is introduced into the measuring tubes of the electromagnetic flow meter under test and the standard electromagnetic flow meter, and the average flow rate error between the standard electromagnetic flow meter and the electromagnetic flow meter under test and the second average flow velocity value of the electromagnetic flow meter under test are measured within a third preset time period. The final zero-velocity removal value is calculated using the average flow rate error, the second average flow velocity value, and the initial zero-velocity removal value, and then saved to the electromagnetic flow meter under test.

[0005] As an improvement to the above scheme, the formula for calculating the sensor coefficient is K=f1 / f2; where K is the sensor coefficient, f1 is the standard average flow rate value, and f2 is the measured average flow rate value.

[0006] As an improvement to the above scheme, the final zero-velocity removal value is calculated as Zero2 = Zero1 - (V1 * E); where Zero2 is the final zero-velocity removal value, Zero1 is the initial zero-velocity removal value, V1 is the second average velocity value, and E is the average flow rate error.

[0007] As an improvement to the above scheme, the initial zero-point velocity removal value and the first average velocity value are opposites of each other.

[0008] As an improvement to the above scheme, the first preset flow rate is greater than the second preset flow rate.

[0009] As an improvement to the above scheme, the second preset flow rate is a flow rate that is greater than the minimum standard flow rate but less than a preset multiple of the range value.

[0010] Accordingly, the present invention also provides a measuring device for calibrating and setting the zero point of an electromagnetic flowmeter, comprising: a transceiver module for acquiring and transmitting data; a first measuring module for measuring the first average flow velocity value of the electromagnetic flowmeter under test within a first preset time period to obtain an initial zero-point flow velocity removal value; a second measuring module for measuring the measured average flow rate value of the electromagnetic flowmeter under test and the standard average flow rate value of a standard electromagnetic flowmeter within a second preset time period; a first calculation module for calculating a sensor coefficient using the measured average flow rate value and the standard average flow rate value; a third measuring module for measuring the average flow rate error between the standard electromagnetic flowmeter and the electromagnetic flowmeter under test within a third preset time period and measuring the second average flow velocity value of the electromagnetic flowmeter under test; and a second calculation module for calculating the final zero-point flow velocity removal value using the average flow rate error, the second average flow velocity value, and the initial zero-point flow velocity removal value.

[0011] As an improvement to the above scheme, the first calculation module includes a first calculation unit, which includes the calculation formula for the sensor coefficient: K=f1 / f2; where K is the sensor coefficient, f1 is the standard average flow rate value, and f2 is the measured average flow rate value.

[0012] As an improvement to the above scheme, the second calculation module includes a second calculation unit. The second calculation unit includes the calculation formula for the final zero-velocity removal value: Zero2=Zero1-(V1*E); where Zero2 is the final zero-velocity removal value, Zero1 is the initial zero-velocity removal value, V1 is the second average velocity value, and E is the average flow rate error.

[0013] Accordingly, the present invention also provides a system for calibrating and setting the zero point of an electromagnetic flowmeter, including a flow calibration device, an electromagnetic flowmeter under test, a standard electromagnetic flowmeter, and the above-mentioned measuring device, wherein both the electromagnetic flowmeter under test and the standard electromagnetic flowmeter are installed on the flow calibration device.

[0014] Implementing this invention has the following beneficial effects:

[0015] This invention enables accurate measurement of both small and large flow rates by the electromagnetic flowmeter, meeting measurement accuracy requirements and improving the measurement accuracy of the electromagnetic flowmeter.

[0016] Specifically, the measurement accuracy of the electromagnetic flowmeter is improved by setting an initial zero point and correcting the initial zero-point velocity using the obtained initial zero-point velocity removal value; calibrating the sensor coefficient of the electromagnetic flowmeter to ensure accurate measurement error at high flow rates; and calibrating the electromagnetic flowmeter at low flow rates and correcting the final zero-point velocity using the obtained final zero-point velocity removal value to ensure accurate measurement error at low flow rates. Attached Figure Description

[0017] Figure 1 is a flowchart of the method for calibrating and setting the zero position of the electromagnetic flowmeter of the present invention.

[0018] Figure 2 is a schematic diagram of the measuring device for calibrating and setting the zero position of the electromagnetic flowmeter of the present invention;

[0019] Figure 3 is a schematic diagram of the system for calibrating and setting the zero position of the electromagnetic flowmeter of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It is hereby declared that the directional terms such as up, down, left, right, front, back, inside, and outside used in this text are based solely on the accompanying drawings and are not intended to specifically limit the invention.

[0021] As shown in Figure 1, the present invention provides a method for calibrating and setting the zero point of an electromagnetic flowmeter, comprising:

[0022] S1. Place the measuring tube of the electromagnetic flowmeter to be tested in a full-pipe static water state;

[0023] It should be noted that when setting the initial zero position, the measuring tube of the electromagnetic flowmeter under test is installed on the flow calibration device, and the measuring tube of the electromagnetic flowmeter under test is filled with water through the flow calibration device. Then, the valves at both ends of the electromagnetic flowmeter under test are closed to form a full pipe static water state.

[0024] S2. Measure the first average flow velocity value of the electromagnetic flowmeter under test within the first preset time period to obtain the initial zero-point flow velocity removal value, and save the initial zero-point flow velocity removal value to the electromagnetic flowmeter under test.

[0025] It should be noted that while waiting for the flow rate to stabilize under the full-pipe static state, the flow rate value of the electromagnetic flowmeter under test is collected in real time within the first preset time period to measure the first average flow rate value within the first preset time period. The initial zero-point flow rate removal value that needs to be corrected is the opposite of the first average flow rate value.

[0026] In this embodiment, the first preset time period is preferably 30 seconds, but it is not limited to this and can be increased or decreased according to actual needs. During this first preset time period, the flow velocity value of the electromagnetic flowmeter under test is collected once per second to measure the first average flow velocity value as Zero1 = 0.011 m / s. Since the initial zero-velocity removal value and the first average flow velocity value are opposites (i.e., the two values ​​are equal but opposite in direction), the initial zero-velocity removal value is -Zero1 = -0.011 m / s. The initial zero-velocity removal value is saved to the electromagnetic flowmeter under test for initial zero-velocity correction.

[0027] S3. Pass a first preset flow rate of water into the measuring tubes of the electromagnetic flowmeter under test and the standard electromagnetic flowmeter, and measure the average flow rate of the electromagnetic flowmeter under test and the standard average flow rate of the standard electromagnetic flowmeter respectively within a second preset time period.

[0028] It should be noted that after releasing the full-pipe static state, the standard electromagnetic flowmeter is also installed in the flow calibration equipment. In this embodiment, a DN50 standard electromagnetic flowmeter is used as the comparison standard sample, with a maximum flow rate of 44 m³ / h and a minimum flow rate of 2.244 m³ / h. During sensor coefficient calibration or high-flow-rate calibration, the valves and water pumps at both ends of the tested electromagnetic flowmeter and the standard electromagnetic flowmeter are opened. The flow calibration equipment is then used to run water at a first preset flow rate to introduce water into the measuring pipes of both the tested and standard electromagnetic flowmeters. At this time, the relationship between the actual flow velocity V1 and the measured flow velocity V2 of the tested electromagnetic flowmeter is V1 = V2 - Zero1. This actual flow velocity V1 is the flow velocity value actually displayed in the display of the tested electromagnetic flowmeter or the flow velocity value after initial calibration.

[0029] Furthermore, the flow rates of the tested electromagnetic flowmeter and the standard electromagnetic flowmeter are collected in real time during the second preset time period to measure the average flow rate of the tested electromagnetic flowmeter and the standard average flow rate of the standard electromagnetic flowmeter during the second preset time period.

[0030] In this embodiment, the first preset flow rate is preferably a large flow rate of 27 m³ / h, which is 0.8 times the range value, but it is not limited to this and other large flow rates can be selected according to actual needs. The second preset time period is 2 minutes, but it is not limited to this and can be increased or decreased according to actual needs. Within the second preset time period, the standard average flow rate of the standard electromagnetic flowmeter is measured to be f1=27.0, and the measured average flow rate of the electromagnetic flowmeter under test is measured to be f2=29.8507.

[0031] S4. Calculate the sensor coefficient using the measured average flow rate and the standard average flow rate, and save the sensor coefficient to the measured electromagnetic flowmeter.

[0032] Specifically, the formula for calculating the sensor coefficient is K=f1 / f2; where K is the sensor coefficient, f1 is the standard average flow rate, and f2 is the measured average flow rate.

[0033] In this embodiment, the standard average flow rate is f1 = 27.0, and the measured average flow rate is f2 = 29.8507. Using the sensor coefficient calculation formula, the sensor coefficient K = 0.9045. The sensor coefficient K is saved to the electromagnetic flowmeter under test for sensor coefficient or high-flow-rate calibration. At this time, the flow rate of the electromagnetic flowmeter under test is consistent with that of the standard flowmeter to ensure accurate measurement error at high flow rates and meet measurement accuracy requirements. The relationship between the actual flow velocity V1 and the measured flow velocity V2 of the electromagnetic flowmeter under test is V1 = K * V2 - Zero1.

[0034] S5. Pass water of a second preset flow rate into the measuring tubes of the electromagnetic flow meter under test and the standard electromagnetic flow meter, and measure the average flow rate error between the standard electromagnetic flow meter and the electromagnetic flow meter under test within a third preset time period, and measure the second average flow velocity value of the electromagnetic flow meter under test.

[0035] It should be noted that during low-flow calibration, the valves and water pumps at both ends of the electromagnetic flowmeter under test and the standard electromagnetic flowmeter are opened. The flow calibration equipment is used to run water at a second preset flow rate, allowing this flow to enter the measuring tubes of both the electromagnetic flowmeter under test and the standard electromagnetic flowmeter. Then, within a third preset time period, the flow rates of the electromagnetic flowmeter under test and the standard electromagnetic flowmeter are collected in real time to measure the average flow rate error between them during this period. Additionally, the flow velocity of the electromagnetic flowmeter under test is collected in real time to measure its second average flow velocity. Furthermore, the first preset flow rate is greater than the second preset flow rate; the second preset flow rate is greater than the minimum standard flow rate but less than a preset multiple of the range value.

[0036] In this embodiment, the second preset flow rate is preferably a small flow rate of 2.3655 m³ / h, which is greater than the minimum standard flow rate and less than 0.1 times the range value, but it is not limited to this and other small flow rates can be selected according to actual needs. The third preset time period is 2 minutes, but it is not limited to this and can be increased or decreased according to actual needs. The average flow rate error E between the standard electromagnetic flowmeter and the electromagnetic flowmeter under test measured within the third preset time period is -10%. The average flow rate error E can be obtained by multiple measurements with different third preset time periods each time. For example, in this embodiment, the average flow rate errors E after two measurements are -0.14% and -0.07% respectively, and the average value is -10%. The second average flow velocity measured within the third preset time period is the actual average flow velocity V1 = 0.334 m / s.

[0037] S6. Calculate the final zero-velocity removal value using the average flow rate error, the second average flow velocity value, and the initial zero-velocity removal value, and save the final zero-velocity removal value to the electromagnetic flowmeter being measured.

[0038] Specifically, the formula for calculating the final zero-velocity removal value is Zero2 = Zero1 - (V1 * E); where Zero2 is the final zero-velocity removal value, Zero1 is the initial zero-velocity removal value, V1 is the second average velocity value, and E is the average flow rate error.

[0039] It should be noted that, based on the second average flow velocity value V1 and the average flow rate error E, the zero-point value to be corrected is Z = V1 * E = 0.334 * (-0.10%) = -0.00034 m / s. The zero-point is then corrected again to make the final zero-point velocity removal value Zero2 = Zero1 - Z = -0.011 - (-0.00034) = -0.01066 m / s. This final zero-point velocity removal value Zero2 is saved to the electromagnetic flowmeter under test for secondary or final zero-point calibration. At this point, the relationship between the actual flow velocity V1 and the measured flow velocity V2 of the electromagnetic flowmeter under test is V1 = V2 * K - Zero2, ensuring accurate measurement error for small flow rates and meeting measurement accuracy requirements.

[0040] For most electromagnetic flowmeters, the error can meet the requirements without re-zeroing. However, re-zeroing can provide better correction for a small number of electromagnetic flowmeters that are on the edge of the error limit, thereby improving the measurement accuracy. The following table compares the data of four tested electromagnetic flowmeters before and after re-zeroing.

[0041] Table 1 shows the data without secondary setting of the zero position:

[0042]

[0043] Table 2 shows the data for setting the zero position a second time:

[0044]

[0045] The two data tables above show that while the error accuracy for high-speed flow and large flow is the same and meets the accuracy requirements, the error for low-speed flow and small flow is larger. Specifically, the error of electromagnetic flowmeter No. 3 in Table 1 at the minimum flow point is 0.50%, which is at the critical point of the 0.5% accuracy error requirement. That is, the error at small flow is large and the accuracy is low for the electromagnetic flowmeter without secondary zero-point setting, thus reducing the measurement accuracy of the electromagnetic flowmeter. Table 2 shows that the error at small flow of the electromagnetic flowmeter after secondary zero-point setting according to this invention is small and accurate, meeting the 0.5% accuracy requirement. Therefore, this invention can achieve accurate measurement of both small and large flow rates for the electromagnetic flowmeter, meeting the measurement accuracy requirements and improving the measurement accuracy of the electromagnetic flowmeter.

[0046] As shown in Figure 2, the present invention also provides a measuring device for calibrating and setting the zero point of an electromagnetic flowmeter, including: a transceiver module 11, used to collect data from the electromagnetic flowmeter under test and a standard electromagnetic flowmeter and send the data to the electromagnetic flowmeter under test.

[0047] The first measurement module 12 is used to measure the first average flow velocity value of the electromagnetic flowmeter under test within a first preset time period to obtain the initial zero-point flow velocity removal value, and to send the initial zero-point flow velocity removal value to the electromagnetic flowmeter under test through the transceiver module 11.

[0048] It should be noted that when the flow rate of the electromagnetic flow meter under test is stable in the full pipe static water state, the flow rate value of the electromagnetic flow meter under test is collected in real time within the first preset time period to measure the first average flow rate value within the first preset time period. The initial zero-point flow rate removal value that needs to be corrected is the opposite of the first average flow rate value, and the initial zero-point flow rate removal value is sent to the electromagnetic flow meter under test.

[0049] In this embodiment, the first preset time period is preferably 30 seconds, but it is not limited to this and can be increased or decreased according to actual needs. During this first preset time period, the flow velocity value of the electromagnetic flowmeter under test is collected once per second to measure the first average flow velocity value as Zero1 = 0.011 m / s. Since the initial zero-velocity removal value and the first average flow velocity value are opposites (i.e., the two values ​​are equal but opposite in direction), the initial zero-velocity removal value is -Zero1 = -0.011 m / s. The initial zero-velocity removal value is saved to the electromagnetic flowmeter under test for initial zero-velocity correction.

[0050] The second measurement module 13 is used to measure the average flow rate of the electromagnetic flowmeter under test and the standard average flow rate of the standard electromagnetic flowmeter within a second preset time period.

[0051] It should be noted that after releasing the full-pipe static state, the standard electromagnetic flowmeter is also installed in the flow calibration equipment. In this embodiment, a DN50 standard electromagnetic flowmeter is used as the comparison standard sample, with a maximum flow rate of 44 m³ / h and a minimum flow rate of 2.244 m³ / h. During sensor coefficient calibration or high-flow-rate calibration, the valves and water pumps at both ends of the tested electromagnetic flowmeter and the standard electromagnetic flowmeter are opened. The flow calibration equipment is then used to run water at a first preset flow rate to introduce water into the measuring pipes of both the tested and standard electromagnetic flowmeters. At this time, the relationship between the actual flow velocity V1 and the measured flow velocity V2 of the tested electromagnetic flowmeter is V1 = V2 - Zero1. This actual flow velocity V1 is the flow velocity value actually displayed in the display of the tested electromagnetic flowmeter or the flow velocity value after initial calibration.

[0052] Furthermore, the flow rates of the tested electromagnetic flowmeter and the standard electromagnetic flowmeter are collected in real time during the second preset time period to measure the average flow rate of the tested electromagnetic flowmeter and the standard average flow rate of the standard electromagnetic flowmeter during the second preset time period.

[0053] In this embodiment, the first preset flow rate is preferably a large flow rate of 27 m³ / h, which is 0.8 times the range value, but it is not limited to this and other large flow rates can be selected according to actual needs. The second preset time period is 2 minutes, but it is not limited to this and can be increased or decreased according to actual needs. Within the second preset time period, the standard average flow rate of the standard electromagnetic flowmeter is measured to be f1=27.0, and the measured average flow rate of the electromagnetic flowmeter under test is measured to be f2=29.8507.

[0054] The first calculation module 14 is used to calculate the sensor coefficient using the measured average flow rate and the standard average flow rate; and to send the sensor coefficient to the measured electromagnetic flowmeter via the transceiver module 11. Specifically, the first calculation module 14 includes a first calculation unit 141, which includes the calculation formula for the sensor coefficient: K=f1 / f2; where K is the sensor coefficient, f1 is the standard average flow rate, and f2 is the measured average flow rate.

[0055] In this embodiment, the standard average flow rate is f1 = 27.0, and the measured average flow rate is f2 = 29.8507. Using the sensor coefficient calculation formula, the sensor coefficient K = 0.9045. The sensor coefficient K is saved to the electromagnetic flowmeter under test for sensor coefficient or high-flow-rate calibration. At this time, the flow rate of the electromagnetic flowmeter under test is consistent with that of the standard flowmeter to ensure accurate measurement error at high flow rates and meet measurement accuracy requirements. The relationship between the actual flow velocity V1 and the measured flow velocity V2 of the electromagnetic flowmeter under test is V1 = K * V2 - Zero1.

[0056] The third measurement module 15 is used to measure the average flow value error between the standard electromagnetic flow meter and the electromagnetic flow meter under test within a third preset time period, and to measure the second average flow velocity value of the electromagnetic flow meter under test.

[0057] It should be noted that during low-flow calibration, the valves and water pumps at both ends of the electromagnetic flowmeter under test and the standard electromagnetic flowmeter are opened. The flow calibration equipment is used to run water at a second preset flow rate, allowing this flow to enter the measuring tubes of both the electromagnetic flowmeter under test and the standard electromagnetic flowmeter. Then, within a third preset time period, the flow rates of the electromagnetic flowmeter under test and the standard electromagnetic flowmeter are collected in real time to measure the average flow rate error between them during this period. Additionally, the flow velocity of the electromagnetic flowmeter under test is collected in real time to measure its second average flow velocity. Furthermore, the first preset flow rate is greater than the second preset flow rate; the second preset flow rate is greater than the minimum standard flow rate but less than a preset multiple of the range value.

[0058] In this embodiment, the second preset flow rate is preferably a small flow rate of 2.3655 m³ / h, which is greater than the minimum standard flow rate and less than 0.1 times the range value, but it is not limited to this and other small flow rates can be selected according to actual needs. The third preset time period is 2 minutes, but it is not limited to this and can be increased or decreased according to actual needs. The average flow rate error E between the standard electromagnetic flowmeter and the electromagnetic flowmeter under test measured within the third preset time period is -10%. The average flow rate error E can be obtained by multiple measurements with different third preset time periods each time. For example, in this embodiment, the average flow rate errors E after two measurements are -0.14% and -0.07% respectively, and the average value is -10%. The second average flow velocity measured within the third preset time period is the actual average flow velocity V1 = 0.334 m / s.

[0059] The second calculation module 16 is used to calculate the final zero-velocity removal value using the average flow rate error, the second average flow velocity value, and the initial zero-velocity removal value; and to send the final zero-velocity removal value to the electromagnetic flowmeter under test via the transceiver module 11. Specifically, the second calculation module 16 includes a second calculation unit 161, and the second calculation unit 161 includes the following formula for calculating the final zero-velocity removal value: Zero2 = Zero1 - (V1 * E); where Zero2 is the final zero-velocity removal value, Zero1 is the initial zero-velocity removal value, V1 is the second average flow velocity value, and E is the average flow rate error.

[0060] It should be noted that, based on the second average flow velocity value V1 and the average flow rate error E, the zero-point value to be corrected is Z = V1 * E = 0.334 * (-0.10%) = -0.00034 m / s. The zero-point is then corrected again to make the final zero-point velocity removal value Zero2 = Zero1 - Z = -0.011 - (-0.00034) = -0.01066 m / s. This final zero-point velocity removal value Zero2 is saved to the electromagnetic flowmeter under test for secondary or final zero-point calibration. At this point, the relationship between the actual flow velocity V1 and the measured flow velocity V2 of the electromagnetic flowmeter under test is V1 = V2 * K - Zero2, ensuring accurate measurement error for small flow rates and meeting measurement accuracy requirements.

[0061] As shown in Figure 3, the present invention also provides a system for calibrating and setting the zero point of an electromagnetic flowmeter, including a flow calibration device 2, a measured electromagnetic flowmeter 3, a standard electromagnetic flowmeter 4, and the aforementioned measuring device 1. Both the measured electromagnetic flowmeter 3 and the standard electromagnetic flowmeter 4 are mounted on the flow calibration device 2. The flow calibration device 2 can operate water flows of different flow rates to be introduced into the measuring tubes of the measured electromagnetic flowmeter 3 and the standard electromagnetic flowmeter 4, and measurement tests are conducted through the measured electromagnetic flowmeter 3, the standard electromagnetic flowmeter 4, and the measuring device 1.

[0062] This invention enables accurate measurement of both small and large flow rates using the electromagnetic flowmeter, meeting measurement accuracy requirements and improving the measurement accuracy of the electromagnetic flowmeter. Specifically, it involves initial zero-point setting of the electromagnetic flowmeter and initial zero-point velocity correction using the acquired initial zero-point velocity removal value; sensor coefficient calibration of the electromagnetic flowmeter to ensure accurate measurement error at large flow rates; and calibration of the electromagnetic flowmeter at small flow rates and final zero-point velocity correction using the acquired final zero-point velocity removal value to ensure accurate measurement error at small flow rates, thereby improving the measurement accuracy of the electromagnetic flowmeter.

[0063] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for calibrating and setting the zero point of an electromagnetic flowmeter, characterized in that, include: The measuring tube of the electromagnetic flowmeter to be tested is placed in a state of full pipe static water; The first average flow velocity value of the electromagnetic flowmeter under test is measured within a first preset time period to obtain an initial zero-point flow velocity removal value, and the initial zero-point flow velocity removal value is saved to the electromagnetic flowmeter under test. A first preset flow rate of water is introduced into the measuring tubes of the electromagnetic flow meter under test and the standard electromagnetic flow meter, and the average flow rate of the electromagnetic flow meter under test and the standard average flow rate of the standard electromagnetic flow meter are measured respectively within a second preset time period. The sensor coefficient is calculated using the measured average flow rate and the standard average flow rate, and the sensor coefficient is saved to the measured electromagnetic flowmeter. A second preset flow rate of water is introduced into the measuring tubes of the electromagnetic flow meter under test and the standard electromagnetic flow meter, and the average flow rate error between the standard electromagnetic flow meter and the electromagnetic flow meter under test is measured within a third preset time period, and the second average flow velocity value of the electromagnetic flow meter under test is measured. The final zero-point velocity removal value is calculated using the average flow rate error, the second average flow velocity value, and the initial zero-point velocity removal value, and the final zero-point velocity removal value is saved to the electromagnetic flowmeter under test. Wherein, the first preset flow rate is greater than the second preset flow rate, and the second preset flow rate is greater than the minimum standard flow rate value but less than the range value of a preset multiple.

2. The method for calibrating and setting the zero point of an electromagnetic flowmeter according to claim 1, characterized in that, The formula for calculating the sensor coefficient is K=f1 / f2; Wherein, K is the sensor coefficient, f1 is the standard average flow rate value, and f2 is the measured average flow rate value.

3. The method for calibrating and setting the zero point of an electromagnetic flowmeter according to claim 1, characterized in that, The formula for calculating the final zero-point velocity removal value is Zero2=Zero1-(V1*E). Wherein, Zero2 is the final zero-point velocity removal value, Zero1 is the initial zero-point velocity removal value, V1 is the second average velocity value, and E is the average flow rate error.

4. The method for calibrating and setting the zero point of an electromagnetic flowmeter according to claim 1, characterized in that, The initial zero-point velocity removal value is the opposite of the first average velocity value.

5. A measuring device for calibrating and setting the zero point of an electromagnetic flowmeter, characterized in that, include: The transceiver module is used to collect and send data. The first measurement module is used to measure the first average flow velocity value of the electromagnetic flowmeter under test within a first preset time period to obtain the initial zero-point flow velocity removal value. The second measurement module is used to measure the average flow rate of the electromagnetic flowmeter under test and the standard average flow rate of the standard electromagnetic flowmeter under the first preset flow rate and within the second preset time period, respectively. The first calculation module is used to calculate the sensor coefficient using the measured average flow rate value and the standard average flow rate value; The third measurement module is used to measure the average flow rate error between the standard electromagnetic flowmeter and the electromagnetic flowmeter under test under the second preset flow rate and within the third preset time period, and to measure the second average flow velocity value of the electromagnetic flowmeter under test. The second calculation module is used to calculate the final zero-point flow velocity removal value using the average flow rate error, the second average flow velocity value, and the initial zero-point flow velocity removal value. Wherein, the first preset flow rate is greater than the second preset flow rate, and the second preset flow rate is greater than the minimum standard flow rate value but less than the range value of a preset multiple.

6. The measuring device according to claim 5, characterized in that, The first calculation module includes a first calculation unit, and the first calculation unit includes the calculation formula for the sensor coefficient: K=f1 / f2; Wherein, K is the sensor coefficient, f1 is the standard average flow rate value, and f2 is the measured average flow rate value.

7. The measuring device according to claim 5, characterized in that, The second calculation module includes a second calculation unit, and the calculation formula for the final zero-point velocity removal value is: Zero2=Zero1-(V1*E). Wherein, Zero2 is the final zero-point velocity removal value, Zero1 is the initial zero-point velocity removal value, V1 is the second average velocity value, and E is the average flow rate error.

8. A system for calibrating and setting the zero point of an electromagnetic flowmeter, characterized in that, It includes a flow calibration device, a measured electromagnetic flow meter, a standard electromagnetic flow meter, and the measuring device according to any one of claims 5-7, wherein the measured electromagnetic flow meter and the standard electromagnetic flow meter are both installed on the flow calibration device.

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