Some standard content:
National Metrology Verification Regulation of the People's Republic of China JJG1033-—2007
Electronagnetic Flowmeters
2007 - 11 21 Issued
Implementation on 2008-02—21
The General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China issued JJG 1033—2007
Verification Regulation of
Electromagnetic Flowmeters
JJG 1033-2007
Replaces the electromagnetic flow part of JJG198—1994
This regulation was approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on November 21, 2007, and will be implemented on February 21, 2008.
Responsible unit: National Technical Committee for Flow and Capacity Measurement Main drafting unit: China National Institute of Metrology Participating drafting unit: Henan Institute of Metrology Shanghai Guanghua-Aiermei Instrument Co., Ltd. Shanghai Chengbo Automation Equipment Co., Ltd.
Beijing Ruipu Electronics Group
Kaifeng Instrument Co., Ltd.
Hangzhou Zhenhua Instrument Co., Ltd.
ABB (China) Co., Ltd.
This regulation entrusts the National Technical Committee for Flow and Capacity Measurement to be responsible for interpreting this regulation Main drafter:|| tt||JJG1033—2007
Meng Tao (China National Institute of Metrology)
Participating drafters:
Zhu Yonghong (Henan Institute of Metrology) Song Jianjun (Shanghai Guanghua-Aiermei Instrument Co., Ltd.) Cheng Xianxi (Shanghai Chengbo Automation Equipment Co., Ltd.) Li Zhenzhong (Beijing Ruipu Electronics Group)
Liang Zhonghai (Kaifeng Instrument Co., Ltd.)
Fang Xiaofeng (Hangzhou Zhenhua Instrument Co., Ltd.) Wang Rongjie (ABB (China) Co., Ltd.) Scope·
2 References
3 Terminology·
4 Overview·
4.1 Working principle
4.2 Structure and purpose
5 Metrological performance requirements
5.1 Accuracy level
5.2 Reference error
5.3 Error expression method and selection principle
S.4 Repeatability·
6 General technical requirements
Random documents·
Appearance·
Sealing
6.5 Protection function·
7 Measuring instrument control
7.1 Verification conditions,
7.2 Verification items and verification methods
7.3 Processing of verification results·
7.4 Verification cycle·
Appendix A Type evaluation outline
JJG 1033—2007
Appendix B Format of verification certificate and verification result notice (inside page) (1)
(2)
(2)
(3)
...(3)
1 Scope
JJG1033—2N7
Verification Procedure for Electromagnetic Flowmeter
This procedure applies to the type evaluation, initial verification, subsequent verification and in-use inspection of electromagnetic flowmeters (hereinafter referred to as flowmeters) installed in closed pipelines. It is not applicable to flowmeters for measuring blood, solid metal and iron ore slurries and open channel flow measurement, nor is it applicable to the verification of insertion electromagnetic flowmeters and electromagnetic water meters. 2 References
The provisions contained in the following standards and regulations constitute the provisions of this procedure through reference. LIF 1004-2004 Flow measurement terms and definitions GB/T 18659-2002 (idt ISO 9104: 1991) Performance evaluation method of magnetic flowmeter
GB/T 18660-2002 (idt ISO 6817: 1992) Method of using magnetic flowmeter
JB/T 9248-1999 Electromagnetic flowmeter
Attention should be paid to the current valid versions of the above-mentioned references. 3 Terms
3.1 Primary device (sensor) (prinary device) Measurement device for the flow of conductive liquids in closed pipes Measurement device for the flow of conductive liquids in closed pipes is used to generate a signal proportional to the flow rate. The primary device mainly includes the following units: a measuring tube through which the conductive liquid to be measured flows, and a pair or more pairs of radially opposed electrodes, which are usually electrically insulated between the inner and outer surfaces, are used to measure the signal generated by the flow of the conductive liquid: an electromagnet that generates a magnetic field in the measuring tube. 3.2 Secondary device (converter) (secondarydevice) is an electric device that converts the induced electromotive force taken out from the secondary device into a standard output signal proportional to the flow rate.
3.3 Flowmeter characteristic coefficient (meter characteristic coefficient) can change the parameters of the flowmeter's metering performance by modifying its value. Note: 1. Due to different processes or names of flowmeters produced by various manufacturers, this parameter may be a sensor coefficient, a converter coefficient, a correction coefficient or other parameters:
2. This parameter may consist of one or a group of parameters. 3.4 Flow conditioner (flowconditioncr) is a component that can reduce vortices and improve velocity distribution. 1
3.5 Reference error (fiducial error) JJG 1033--2007
The error of flow divided by the specific value of the flowmeter. Note: This specific value is generally called the reference value, which can be the upper limit of the flowmeter's range or nominal range. 4 Overview
4.1 Working principle
In a closed pipeline, a magnetic field perpendicular to the flow direction is set up, and the flow rate is calculated by measuring the induced electromotive force generated by the movement of the conductive liquid in the magnetic field. 4.2 Structure and use
The flowmeter consists of a primary device and a secondary device. According to the combination of the primary device and the secondary device, the flowmeter can be divided into a split type and an integrated type; the flowmeter is mainly used to measure the volume flow of conductive liquids. 5 Metering performance requirements
5.1 Accuracy level
The accuracy level and maximum allowable error of the flowmeter within the specified flow range shall comply with the provisions of Table 1. The flowmeter error is expressed using the relative indication error.
Table 1 Accuracy grade and maximum allowable error
Accuracy grade
Maximum allowable error
Accuracy grade
Maximum allowable error
Note: Grades without brackets are preferred. 5.2 Reference error
(±0.25%)
For flowmeters that use instantaneous flow indication, the error can also be expressed as the error. The maximum allowable error series should comply with the provisions of Table 1. The accuracy grade is no longer given in the expression of the verification results, but the maximum allowable error is used, and FS should be marked after the maximum allowable error. For example, 10.5%FS. 5.3 Error expression method and selection principle
In the first calibration of a flow meter, the error expression method of the flow meter shall be given in accordance with the methods in 5.1 and 5.2; for flow meters that use a combination of relative indication error and reference error to express the error, "the first calibration shall also use a unified method to express its error.
5.4 Repeatability
The repeatability of the flow meter shall not exceed 1/3 of the absolute value of the maximum allowable error specified for the corresponding accuracy grade. 6 General technical requirements
6.1 Random documents
JJG 1033---2007
The flowmeter should be accompanied by an instruction manual, which should explain the technical conditions and the metering performance of the flowmeter. The flowmeter that is periodically calibrated should also have the calibration certificate of the previous calibration. 6.2 Identification
6.2.1 The flowmeter should have a nameplate. The meter body or nameplate should indicate: a. Product and manufacturer name;
b. Product specifications and model:
c. Factory number;
d. Manufacturing meter license mark and number: e. Maximum working pressure;
f. Applicable working temperature range;
g. .Nominal diameter;
h. Flow rate (or velocity) range;
i. Accuracy level (or maximum allowable error): j. Flow meter characteristic coefficient;
k: Explosion-proof level and explosion-proof certificate number (for explosive gas environment); 1. Protection level;
m. Year and month of manufacture.
6.2.2 The flow meter should have obvious flow direction markings. 6.3 Appearance
6.3.1 The appearance of the newly manufactured flow meter should be well treated and should not have burrs, scratches, cracks, rust, mildew spots, and the coating should not have peeling or flaking. 6.3.2 The welding of the connection part of the flow meter body should be smooth and clean, and there should be no cold welding, desoldering and other phenomena. 6.3.3 The sealing surface should be flat and free of damage. 6.3.4 The numbers in the display window should be eye-catching and neat, and the symbols and signs indicating the functions should be complete, clear and correct; the protective glass on the reading device should have good transparency, without defects that distort the reading and hinder the reading; the buttons should not be sticky. bzxZ.net
6.4 Exposure seal
Under the test installation conditions, the flow meter is kept at the maximum test pressure for 5 minutes, and there should be no leakage at the connection between the flow meter and the upstream and downstream straight pipe sections
6.5 Protection function
The flow meter should have a protection function for the modification of the flow characteristic coefficient, which can avoid accidental changes or record the historical modification process. The coefficient value should be recorded during the calibration and indicated in the calibration certificate. The value of the characteristic coefficient of the flow meter for periodic calibration should be the same as the coefficient set during the last calibration and has not been modified. 7 Measuring instrument control
Measuring instrument control includes type evaluation, initial verification, subsequent verification and in-use inspection. Appendix A is the evaluation outline of type 3
.
7.1 Verification conditions
7.1.1 Flow standard device
JJG 1033--2007
7.1.1.1 The flow standard device (hereinafter referred to as the device) and its supporting instruments shall have a valid verification certificate. 7.1.1.2 The expanded uncertainty of the measurement result of the device shall not be greater than 1/3 of the absolute value of the maximum allowable error of the flow meter being tested.
When the vapor pressure of the verification liquid is higher than the atmospheric pressure, the device shall be closed. 7.1.1.33
7.1.1.4 The electrical equipment used for verification shall be grounded. 7.1.1.5 The equipment used to collect the output signal of the meter under test during the calibration shall match the collected signal and meet the calibration requirements.
7.1.1.6 If the instantaneous flow of the meter under test is to be calibrated, the flow stability of the device shall meet the following requirements: for flow meters with a maximum allowable error of equal to or less than 0.5%, the flow stability of the device shall be better than 0.2%; for flow meters with a maximum allowable error of greater than 0.5%, the flow stability of the device shall be better than 0.5%. 7.1.2 Calibration liquid
7.1.2.1 The calibration liquid can generally be clear water without air, fibers, magnetic particles and other visible particles. If other liquids are used, their type (including commercial name), viscosity, density and conductivity shall be stated in the calibration certificate.
7.1.2.2 During the calibration, the liquid shall always fill the test pipe and flow in a single-phase stable and vortex-free manner. 7.1.2.3 The pressure of the test liquid at any point in the pipeline system and flowmeter should be higher than its saturated vapor pressure. For easily vaporized test liquids, there should be a certain back pressure downstream of the flowmeter. The recommended back pressure is 1-25 times the saturated vapor pressure of the test liquid at the highest test temperature. 7.1.2.4 The conductivity m of the test liquid is within the range of 5mS/m (50S/cm) to .500mS/m (5000uS/cm), or otherwise determined according to the technical indicators given by the flowmeter manufacturer. 7.1.2.5 The temperature range of the calibration liquid should be between 4℃ and 35℃. During each calibration process at each flow point, the liquid temperature change should not exceed ±0.5
7.1.3 Calibration environmental conditions
7.1.3.1 The atmospheric environmental conditions should generally meet the following requirements: - Ambient temperature: 5℃～35℃;
-Relative humidity: 15%-85%;
-Atmospheric pressure: 86kPa～106kPac
7.1.3.2 The AC power supply voltage should be (220±22)V, and the power supply frequency should be (50±2.5)Hz. You can also use a suitable AC or DC power supply (such as 24V DC power supply) according to the requirements of the flow meter. 7.1.3.3 The external magnetic field should be so small that the effect on the flow meter can be ignored. 7.1.3.4 The mechanical vibration and noise should be so small that the effect on the flow meter can be ignored. 7.1.4 Installation conditions
JJG 1033--2007
7.1.4.1 The length of the straight pipe section on the downstream side of the flowmeter The length of the pipe section on the downstream side of the flowmeter shall be determined according to the requirements of the flowmeter instruction manual. If there is no provision in the instruction manual, the flowmeter shall be installed in a straight pipe section at least 10 times the nominal diameter (1ODN) away from any downstream disturbance component. When the upstream straight pipe section is not long enough, a flow conditioner can be installed. The length of the pipe section during installation shall meet the requirements of the flow conditioner instruction manual.
7.1.4.2 Requirements for the straight pipe sections upstream and downstream of the flowmeter The inner wall of the straight pipe sections upstream and downstream of the flowmeter shall be clean, without obvious dents, brittleness and peeling. In the absence of specific regulations by the manufacturer, the deviation between the inner diameter of the flow meter and the downstream true pipe section and the flow meter measuring pipe diameter should be less than 3%:
7.1.4.3 During installation, the flow distance marked on the flow meter should be consistent with the direction of fluid flow. : 7.1.4.4 There should be no leakage at the connection between the flow meter and the test pipe section; the sealing block at the connection should not protrude into the fluid. 7.1.4.5 For flowmeters with special installation requirements, they shall be installed strictly in accordance with their instructions. 7.1.5 The time of the first measurement shall not be less than the maximum measurement time of the device and the flowmeter under test. 7.1.6 When the pulse output of the meter under test is used for calibration, the number of pulses recorded in a calibration shall not be less than [10 times the reciprocal of the absolute value of the maximum allowable error:
7.1.7 The flowmeter input signal
shall be collected and processed in accordance with the provisions of the flowmeter manual. For flowmeters with multiple signal inputs, the inspection method or the method recommended in the manual shall be used first. If the requirements are not met, it is recommended to use the pulse output of the flowmeter for inspection.
7.1.8 The flowmeter grounding shall be carried out and inspected in accordance with the requirements of the flowmeter manual. The designated liquid and secondary device should be at an intermediate potential. 7.2 Verification items Verification method 7.2.1 Verification item list Verification item list Random documents, labels and appearance Machine indication error (or indication error) Second verification Note: The inspection is not allowed, which means that no inspection is required. 7.2.2 Inspection of random items, labels and appearance 7.2.2.1 Check that the random items meet the requirements of Section 6.1. Subsequent inspection is for secondary inspection. 7.2.2.2 Use the traceability method to check the label and appearance of the flowmeter, and the results should meet the requirements of Sections 6.2~6.3. 7.2.3 Sealing inspection 1033—2007
After installing the flowmeter on the device, pass the test liquid to the maximum test pressure, check the tightness of the flowmeter, and it should meet the requirements of Section 6.4.
7.2.4 Verification of relative indication error (or reference error) 7.2.4.1 Pre-operation inspection
Connect, turn on, preheat, and check the setting of flowmeter parameters and zero calibration according to the method specified in the flowmeter manual.
7.2.4.2 Let the verification liquid flow through the flowmeter, and let the flowmeter be in normal operation. Wait for the liquid temperature, pressure and flow rate to stabilize before formal verification. 7.2.4.3 Verification flow points
The flowmeter verification should include the following flow points: 4max, qmin, 0.10qmax, 0.25gmx, 0.50gmx and 0.75qmx. When the verification point is less than qmm, the verification point can be cancelled. During the calibration process, the deviation between the actual measured flow rate and the set flow rate at each flow point shall not exceed ±5% or ±1%9mx
7.2.4.4, Number of calibrations
For flow meters using relative indication error, the number of repeated calibrations for each flow point with an accuracy level equal to or better than 0.2 shall not be less than 6 times; the number of repeated calibrations for each flow point with an accuracy level lower than 0.2 shall not be less than 3 times.
For flow meters using reference error, the number of repeated calibrations for each flow point shall not be less than 3 times. 7.2.4.5 Verification procedure
(1) Adjust the flow rate to the specified flow rate value and wait for the flow rate, temperature and pressure to stabilize: (2) Record the initial indications of the standard instrument and the flow meter being tested (or reset to zero), and start the standard instrument (or the recording function of the standard instrument) and the flow meter being tested (or the output function of the flow meter being tested) at the same time; (3) After running for a period of time according to the device operation requirements, stop the standard instrument (or the recording function of the standard instrument) and the flow meter being tested (or the output function of the flow meter being tested), and record the final indications of the standard instrument and the flow meter being tested; (4) Calculate the cumulative flow value or instantaneous flow value recorded by the flow meter and the standard instrument respectively. 7.2.4.6 In each verification, the indication of the flow meter's return instrument, the indication of the standard instrument and the verification time should be read and recorded. The temperature and pressure of the fluid at the standard instrument and flow meter should also be measured and recorded as needed. 7.2.4.7 Calculation of relative indication error
(1) The relative indication error of a flow meter at each flow point after a single calibration is: E, = 0) × 100%
E, -- (g)
×100%
Wherein: E, — — relative indication error of the flow meter under test at the ith calibration point, %; 6
JJG1033—2007
Q; — — the cumulative flow value displayed by the flow meter during the ith calibration point, m; (Q); — the cumulative flow value converted from the standard device to the state of the flow meter during the ith calibration point, m: 95 — the instantaneous flow value displayed by the flow meter during the ith calibration point, which can be the average of the instantaneous flow values read multiple times during a test, m2/h: (4), — — the instantaneous flow value converted from the standard device to the state of the flow meter during the ith calibration point, m'/h.
When the pulse output of the meter under test is used for calibration, Q can be calculated as follows: N
Where: N is the number of pulses output by the flow meter under test at the ith calibration point; (3)
is the flow meter coefficient, which is the number of pulses emitted by the flow meter when a unit volume of fluid flows through the flow meter. It should be obtained from the flow meter manual or nameplate, (m\)\; If the manufacturer has other regulations, it should be calculated according to the regulations in the flow meter manual.
In formula (1), for (Q), calculate as follows: (Q.), - (V.), [1-β(.-8m)]. [1 + x(p-pm)] In the formula: (V); is the actual volume of the liquid measured by the standard instrument during the second calibration at the ith calibration point, m; β is the volume expansion coefficient of the calibration liquid under the calibration state, ℃1; (4)
g,.-- are the liquid temperatures of the standard instrument and the flow meter at the ith calibration point during the second calibration, C; r is the compression coefficient of the calibration liquid under the calibration state, Pa-1; p, force m" are the liquid repulsion forces at the standard instrument and the flow meter at the ith calibration point during the second calibration, Pa. When the difference between, ㎡ is less than 5℃, and P, is less than 0.1MPa, the above formula can be simplified to (Q): = (V):
When using the mass method to calibrate the device, the density of the liquid used for calibration needs to be measured. At the same time, the influence of air buoyancy should be taken into account. The displayed mass is converted to the actual volume (V.) according to the following formula: M
(V), = c
Formula: M, - the mass indicated by the weighing device during the first calibration, kg; pl——density of the liquid used for calibration, kg/n; C——buoyancy correction coefficient.
The buoyancy correction is calculated as follows:
prpr - p.)
ot(pr - pa)
Where: e—-ambient atmospheric density, kg/m; Pr——weight density of the weighing device, kg/m. If the weighing device does not use weights when calibrating the flowmeter, then formula (7) is rewritten as: (6)
EIG 1033--2007
When the meter under test is still using simulated signal or lazy rate input for calibration, 4 should be calculated according to the method specified in the flow meter production or instruction manual; if the output signal of the meter under test is honey, the following calculation is generally used: lI
Irx Thn
Wu:
First: The instantaneous value of the flowmeter output signal during the first calibration can be the average of multiple measurements during the test;
m... - The upper limit of the flowmeter output signal range, which should be obtained from the flowmeter manual or nameplate; - The lower limit of the flowmeter output signal range, which should be obtained from the flowmeter manual or nameplate: 4mx - The flow rate corresponding to the flowmeter output at Imx, m/h. Wu (2) (9), calculated as follows:
Calibration time, 54
(Q.2×3600
(2 ）The relative indication error of the flowmeter at each calibration flow point is calculated as follows: E,-E
Formula: E = relative indication error of the flowmeter at the first calibration point, %: number of calibration points
(3) The relative indication error E of the flowmeter is the maximum error among the relative indication errors of each flow point of the flowmeter: The relative indication error of the flowmeter shall comply with the requirements of Section 5.1 of this standard. 7.2.4.8 Error calculation
(1) The reference error of the flowmeter at a single calibration flow point can be calculated according to formula (13). If the flowmeter manufacturer has its own specifications, it can be calculated according to its requirements
(,), 4(g)
武中：（）…the first, calibration point, the second, the measured flow meter’s indication error.%（2）The reference error of each calibration flow meter is calculated as follows:（E）
武小，（）the apparent error of the flow meter under test, 雅（3）The non-application error E of the flow meter is the maximum error among the apparent errors of each flow meter’s flow points. The application error of the flow meter shall comply with the requirements of 5.2 of this regulation. 7.2.5 Calculation of flow meter repeatability
When each flow point is calibrated twice, the repeatability of the flow meter using relative indication error is calculated as follows (14)8Calculate as follows:
Calibration time, 54
(Q.2×3600
(2) The relative indication error of each calibration flow point of the flow meter is calculated as follows: E,-E
Formula: E=the relative indication error of the flow meter at the first calibration point, %: the number of calibration points
(3) The relative indication error E of the flow meter is the maximum error among the relative indication errors of each flow point of the flow meter: The relative indication error of the flow meter should comply with the requirements of Section 5.1 of this standard. 7.2.4.8 Periodic error calculation
(1) The reference error of the flow meter at a single calibration flow point can be calculated according to formula (13). If the flow meter manufacturer has its own specifications, it can be calculated according to its own requirements
(,), 4(g)
武中：（）…the first, calibration point, the second, the measured flow meter’s indication error.%（2）The reference error of each calibration flow meter is calculated as follows:（E）
武小，（）the apparent error of the flow meter under test, 雅（3）The non-application error E of the flow meter is the maximum error among the apparent errors of each flow meter’s flow points. The application error of the flow meter shall comply with the requirements of 5.2 of this regulation. 7.2.5 Calculation of flow meter repeatability
When each flow point is calibrated twice, the repeatability of the flow meter using relative indication error is calculated as follows (14)8Calculate as follows:
Calibration time, 54
(Q.2×3600
(2) The relative indication error of each calibration flow point of the flow meter is calculated as follows: E,-E
Formula: E=the relative indication error of the flow meter at the first calibration point, %: the number of calibration points
(3) The relative indication error E of the flow meter is the maximum error among the relative indication errors of each flow point of the flow meter: The relative indication error of the flow meter should comply with the requirements of Section 5.1 of this standard. 7.2.4.8 Periodic error calculation
(1) The reference error of the flow meter at a single calibration flow point can be calculated according to formula (13). If the flow meter manufacturer has its own specifications, it can be calculated according to its own requirements
(,), 4(g)
武中：（）…the first, calibration point, the second, the measured flow meter’s indication error.%（2）The reference error of each calibration flow meter is calculated as follows:（E）
武小，（）the apparent error of the flow meter under test, 雅（3）The non-application error E of the flow meter is the maximum error among the apparent errors of each flow meter’s flow points. The application error of the flow meter shall comply with the requirements of 5.2 of this regulation. 7.2.5 Calculation of flow meter repeatability
When each flow point is calibrated twice, the repeatability of the flow meter using relative indication error is calculated as follows (14)8
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