PDF Actual Sample: JJG 1030-2007 (Release/modified date: 2019-11-30/2019-12-03. Wayne Zheng et al.)
| Standard ID | JJG 1030-2007 (JJG1030-2007) |
| Description (Translated English) | Verification Regulation of Ultrasonic Flowmeters |
| Sector / Industry | Metrology & Measurement Industry Standard |
| Classification of Chinese Standard | A53 |
| Classification of International Standard | 17.120 |
| Word Count Estimation | 30,350 |
| Date of Issue | 2007-08-21 |
| Date of Implementation | 2007-11-21 |
| Older Standard (superseded by this standard) | JJG 198-1994 |
| Quoted Standard | AQSIQ Announcement No. 142 of 2007 |
| Drafting Organization | China Institute of Metrology |
| Administrative Organization | National Flow & Volume Capacity Measurement Technical Committee |
| Regulation (derived from) | AQSIQ Announcement No. 142 of 2007 |
| Issuing agency(ies) | State Administration of Quality Supervision, Inspection and Quarantine |
| Summary | This standard applies to the time difference method for the principle of the closed pipe using ultrasonic flowmeter type evaluation, initial verification, testing and use of follow-up inspection. This procedure does not apply to open channels or culverts ultrasonic flow measuring instruments of the test. |
ENGLISH: JJG 1030-2007 (Translated) JJG 1030-2007
NATIONAL METROLOGY TECHINICAL SPECIFICATION
OF THE PEOPLE’S REPUBLIC OF CHINA
Ultrasonic Flowmeters
超声流量计
ISSUED ON: AUGUST 21, 2007
IMPLEMENTED ON: NOVEMBER 21, 2007
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine
_______________________________________________________________________
This Regulation was approved by General Administration of Quality Supervision,
Inspection and Quarantine on August 21, 2007, and shall be implemented since
November 21, 2007.
Jurisdiction organization:
National Flow and Capacity Measurement Technical Committee
Main drafting organizations:
National Institute of Metrology, China
Natural Gas Chengdu Branch, National Crude Oil Large Flowrate Measurement
Station
Participating drafting organizations:
National Water Large Flowrate Measurement Station
Tianjin Institute of Metrological Supervision and Testing
Daniel Measurement and Control Department of Emerson Process Management
Co., Ltd.
Beijing CHANGMIN Tech Co., Ltd.
Beijing WEIYEYUANGUAN Science & Trade Co., Ltd.
Shenzhen JIANHENG Industrial Automation System Co., Ltd.
Tangshan HUIZHONG Instrument Co., Ltd.
National Flow and Capacity Measurement Technical Committee is entrusted for
interpretation of this Regulation.
Replacing “Ultrasonic Flow”
part in JJG 198-1994
Verification Regulation of Ultrasonic
Flowmeters
Main drafters of this Regulation:
Wang, Chi (National Institute of Metrology, China)
Qiu, Fengchun (Natural Gas Chengdu Branch, National Crude Oil Large Flowrate
Measurement Station)
Participating drafters:
Miao, Yusheng (National Water Large Flowrate Measurement Station)
Chen, Xing (Tianjin Institute of Metrological Supervision and Testing)
Wang, Shuishan (Daniel Measurement and Control Department of Emerson
Process Management Co., Ltd.)
Pu, Qihuan (Beijing CHANGMIN Tech Co., Ltd.)
Shi, Lei (Beijing WEIYEYUANGUAN Science & Trade Co., Ltd.)
Xiao, Cong (Shenzhen JIANHENG Industrial Automation System Co., Ltd.)
Zhang, Lixin (Tangshan HUIZHONG Instrument Co., Ltd.)
Table of Contents
1 Scope ... 5
2 References ... 5
3 Terms and Definitions ... 6
4 Overview ... 8
5 Requirements of Metrological Performance ... 10
6 General Technical Requirements ... 11
7 Control of Measuring Instrument ... 12
Appendix A Type Evaluation of Ultrasonic Flowmeter ... 22
Appendix B Special Requirements of On-site Verification ... 33
Appendix C In-use Inspection ... 35
Appendix D Installation Requirements of Ultrasonic Flowmeter ... 42
Appendix E Format of Verification Certificate (inner page) ... 45
Verification Regulation of Ultrasonic Flowmeters
1 Scope
This Regulation is applicable to the type evaluation, initial verification, subsequent
verification and in-use inspection of ultrasonic flowmeters for closed pipes (hereinafter
referred to as flowmeters), which takes time difference method as the principle.
This Regulation is not applicable to the verification of ultrasonic flow measuring
instrument in open channels and closed conduits.
2 References
Through reference, the clauses included in the following standards and regulations
become the clauses of this Regulation.
JJF 1001-1998 General Terms in Metrology and Their Definitions
JJF 1004-2004 Metrological Terms and Their Definitions for Flow Rate
GB 3836 Electrical Apparatus for Explosive Gas Atmospheres
GB/T 18604-2001 Measurement of Natural Gas Flow by Ultrasonic Flow Meter
GB 17820-1999 Natural Gas
GB 50251-2003 Code for Design of Gas Transmission Pipeline Engineering
GB/T 13609-1999 Natural Gas - Sampling Guidelines
GB/T 13610-2003 Analysis of Natural Gas by Gas Chromatography
GB/T 17747.2-1999 Natural Gas - Calculation of Compression Factor - Part 2:
Calculation Using Molar - Composition Analysis
ISO 17089: 2004 (CD) Measurement of Fluid Flow in Closed Conduits - Ultrasonic
Meters for Gas; Meters for Fiscal and Allocation Measurement
ISO/TR 12765: 1997 Measurement of Fluid Flow in Closed Conduits - Methods Using
Transit Time Ultrasonic Flowmeters
AGA Report-1992 No.8 Compressibility Factors of Natural Gas and Other Related
Hydrocarbon Gases
AGA Report No.9-1998 Measurement of Gas by Multipath Ultrasonic Meters
AGA Report No.10-2003 Speed of Sound in Natural Gas and Other Related
Hydrocarbon Gases
ANSI/API MPMS 5.8-2004 Measurement of Liquid Hydrocarbons by Ultrasonic Flow
Meters Using Transit Time Technology
Please make sure to adopt the currently valid version of the above-mentioned
references.
3 Terms and Definitions
3.1 Ultrasonic Flowmeter
Ultrasonic flowmeter refers to a flowmeter which utilizes the transmission characteristic
of ultrasonic wave in fluid to measure flow.
3.2 Ultrasonic Transducer
Ultrasonic transducer refers to a device which can generate acoustic output under the
effect of electric signal and transduce acoustic signal to electric signal.
3.3 Wetted Ultrasonic Meters
Wetted ultrasonic meters refers to flowmeters which embed transducer into fluid
pipelines; allow the transducer to directly contact the fluid.
3.4 Clamp-on Ultrasonic Meters
Clamp-on ultrasonic meters refers to flowmeters which fixate transducer outside fluid
pipelines; whose acoustic wave transmission path penetrates through the wall of fluid
pipelines.
3.5 Transit Time
Transit time refers to the time of ultrasonic signal’s transmission in the fluid medium
part.
3.6 Acoustic Path
Acoustic path refers to the actual path of ultrasonic signal’s transmission among paired
ultrasonic transducers.
3.7 Transmission Angle
Transmission angle refers to the included angle between acoustic path and pipeline’s
axes.
3.8 Single-path Meter
Single-path meter refers to a flowmeter that merely has one pair of transducers.
3.9 Dual-paths Meter
Dual-paths meter refers to a flowmeter that has two pairs of transducers.
3.10 Multiple-paths Meter
Multiple-paths meter refers to a flowmeter that has above two pairs of transducers.
3.11 Meter Body
Meter body refers to a pipe section which is adopted for the installation of components
like ultrasonic transducer; can comply with the stipulations of relevant standards in all
the aspects after going through special manufacture.
3.12 Zero-flow Reading
Zero-flow reading refers to flowmeter’s maximum flowrate reading when the medium
is under a stationary state.
3.13 Pulse Factor
Pulse factor refers to pulse count sent out by a flowmeter when a unit volume of fluid
flows through the flowmeter. Generally speaking, it is also known as K factor, which
shall be expressed in symbol K.
3.14 Flow Conditioner
Flow conditioner refers to a component that can reduce vortex and improve the
distribution of speed.
3.15 Signal Processing Unit
Signal processing unit is constituted of electronic components and microprocessor
system. It is a part of flowmeter.
3.16 Transition Flowrate (qt)
Transition flowrate refers to a flow value between the maximum flow and the minimum
flow. It segments the range of flow into two zones with different allowable errors,
namely, “high zone” and “low zone”.
3.17 Meter Factor
Meter factor refers to a factor that is used to correct the value indicated by flowmeter
in accordance with the result of actual flow verification of the flowmeter. The value is
the ratio of the value indicated by the standard to the value indicated by flowmeter.
Generally speaking, it is expressed in symbol F.
4 Overview
4.1 Operating Principle
Flowmeter takes the measurement of the relations between the time and the flow of
acoustic wave’s transmission in flowing medium as the principle. Generally speaking,
it is believed that acoustic wave’s actual transmission speed in fluid is constituted of
acoustic wave’s transmission speed (cf) under the stationary state of the medium, and
the component of fluid’s axial average flow rate (vm) in the direction of acoustic
transmission. As it is shown in Figure 1, the relations between the downstream and
upstream transmission time, and the various components are as follows:
Where,
tup---time of ultrasonic wave’s upstream transmission in fluid;
tdown---time of ultrasonic wave’s downstream transmission in fluid;
L---length of acoustic path;
cf---ultrasonic wave’s transmission speed in fluid;
vm---fluid’s axial average flow rate;
ϕ---transmission angle.
Figure 1 -- Universal Sketch Map
The two formulas in Formula (1) may be utilized to obtain the formula of fluid flow rate.
Or, similar methods may also be adopted to obtain the transmission speed of acoustic
wave.
Use mathematical functional relationship to unite the obtained fluid flow rates
( ) of multiple acoustic paths. Thus, an estimated value ( ) of
pipeline’s average flow rate may be obtained. Multiply it by flow area (A), then, volume
flow rate (qv) may be obtained, as it is shown in Formula (4):
Where,
Where,
k---number of acoustic paths.
NOTE: even if the number of acoustic paths is provided, the precise form of
will be vary with the arrangement of acoustic paths and the
different calculation methods of numerical value.
4.2 Structural Form
4.2.1 Composition
Flowmeter is mainly constituted of meter body, ultrasonic transducer and its installation
parts, signal processing unit, and (or) flow computer. In terms of on-site wetted
ultrasonic meters and clamp-on ultrasonic meters, pipelines where transducer is
installed may be used as meter body. The transducer of wetted ultrasonic meters
directly contacts the fluid being measured, while the transducer of clamp-on ultrasonic
meters is tightly installed on the external wall of pipelines.
4.2.2 Form
4.2.2.1 In accordance with the installation mode of transducer, flowmeter may be
divided into two forms, namely, wetted and clamp-on.
4.2.2.2 In accordance with the different numbers of transducers, wetted ultrasonic
meters may be divided into single-path meter, dual-paths meter and multiple-paths
meter.
4.2.2.3 The output mode of flowmeter includes: pulse output, analog output and digital
communication output, etc.
5 Requirements of Metrological Performance
5.1 Grade of Accuracy
Table 1 provides recommended accuracy grade series. If a grade of accuracy that is
not listed in this table is adopted, the maximum allowable error needs to comply with
corresponding principles in Table 1 and needs to be clearly indicated in flowmeter
product instruction and flowmeter nameplate. Within the flow range of qt ≤ q ≤ qmax, the
maximum allowable error of flowmeter shall comply with the stipulations in Table 1.
Within the flow range of qmin ≤ q ≤ qt, the maximum allowable error shall not exceed
twice of the maximum allowable error stipulated in Table 1. Furthermore, in terms of
gas flowmeter, the corresponding flow rate of qt shall be not more than 3 m/s; in terms
of liquid flowmeter, the corresponding flow rate of qt shall be not more than 0.3 m/s.
Table 1
5.2 Repeatability
Repeatability of flowmeter shall not exceed 1/5 of the absolute value of the maximum
allowable error stipulated by the corresponding grade of accuracy.
5.3 Flowmeter Factor Adjustment
If meter factor is changed during verification, then, the verification certificate shall
clearly indicate the previous meter factor, the meter factor after the current adjustment
and the amount of meter factor adjustment.
5.4 Requirements of Two-way Measurement Flowmeter
Flowmeter that allows two-way measurement shall be respectively verified in two
measurement directions.
5.5 Requirements of Clamp-on Flowmeter
In terms of clamp-on flowmeter, all the transducers shall be verified; verification shall
be conducted under pipe diameter that is as identical to the adopted pipe diameter as
possible. If the ratio of the used pipe diameter to the verification pipe diameter is larger
than 2, or, less than 1/2, then, the flowmeter in use shall add an additional error of
0.5%.
Grade of Accuracy
Maximum Allowable
Error E
6 General Technical Requirements
6.1 Product Documents
6.1.1 Flowmeter shall be accompanied by an instruction for use.
6.1.2 In terms of clamp-on ultrasonic meters, the instruction for use shall describes
flowmeter’s installation methods and operating requirements in details.
6.1.3 The instruction for use of flowmeter shall provide the operating pressure range
and operating temperature range of transducers; provide the geometric dimensions of
the installation of transducers. In the product documents, wetted ultrasonic meters
shall include an inspection report of geometric dimensions of the flowmeters in exit-
factory inspection.
6.1.4 Flowmeters, which are under periodic verification, shall also have the previous
verification certificate and the inspection report of various in-use inspections after the
previous verification.
6.2 Nameplate and Marking
6.2.1 Flowmeter shall have marking of flow direction.
6.2.2 Flowmeter shall have a nameplate. Generally speaking, meter body or
nameplate shall indicate:
a. Name of manufacturer;
b. Product name and model;
c. Exit-factory serial number;
d. Marking and serial number of permit of manufacturing metrological instruments;
e. Pressure rating (merely restricted to wetted flowmeter);
f. Nominal diameter or applicable pipe diameter range;
g. Applicable operating pressure range and operating temperature range;
h. The maximum, minimum flow or flow rate under operating conditions;
i. Transitional flowrate (when flowmeter has this index);
j. Grade of accuracy;
k. Explosion-proof grade and explosion-proof certificate number (merely restricted
to explosion-proof flowmeter);
l. Year and month of manufacture;
And other relevant technical indexes.
6.2.3 Each pair of ultrasonic transducers shall have permanent uniqueness marking
and installation marking in obvious positions.
6.2.4 When transducer’s signal cable needs to make one-to-one correspondence with
ultrasonic transducer, there shall be permanent uniqueness marking and installation
marking in obvious positions.
6.3 Appearance
6.3.1 Newly manufactured flowmeter shall have satisfying surface treatment; there
shall be no phenomena like burrs, scratches, cracks, corrosion, mildew stains or
stripping of coating. The sealed surface shall be flat; there shall be no damages.
6.3.2 The welding of the connected part of flowmeter body shall be flat and smooth;
there shall be no phenomena like insufficient soldering or de-soldering.
6.3.3 Connectors must be firm and reliable. Connectors shall not become loosened or
fall off due to vibration.
6.3.4 The displayed figures shall be striking and orderly. Character symbols and
markings that express functions shall be complete, distinct and neat.
6.3.5 Keys shall have moderate hand feeling; there shall be no adhesion phenomenon.
6.3.6 The various markings of flowmeter shall be correct. The protective glass on the
reading device shall have satisfying transparency; there shall be no defects that would
interfere with the reading, for example, distorted reading.
6.4 Protective Function
Flowmeter shall have the function of protecting flowmeter factor and recording the
historic modification process, so as to avoid any accidental modification. The value of
flowmeter factor shall be identical to the factor that is input in the previous verification
and shall not be amended.
6.5 Air-tightness
Verify the medium under the maximum experimental pressure, maintain for 5 min,
there shall be no leakage in the various ports of the flowmeter body.
7 Control of Measuring Instrument
The control of measuring instrument includes type evaluation, initial verification,
subsequent verification and in-use inspection. Appendix A stipulates the test conditions,
items and methods of type evaluation. Appendix B stipulates the special requirements
of on-site verification. Appendix C stipulates the test conditions, items and methods of
in-use inspection.
7.1 Verification Conditions
7.1.1 Requirements of flow calibration device
7.1.1.1 Flow calibration device (hereinafter referred to as device) and its matching
instrument shall have valid verification certificate.
7.1.1.2 Uncertainty of the measurement result of the device shall be not larger than
1/3 of the absolute value of the maximum allowable error of the flowmeter being
verified.
7.1.1.3 When the vapor pressure of liquid used for verification is higher than the
ambient atmospheric pressure, the device shall be sealed.
7.1.1.4 When the temperature of fluid that flows through the flowmeter needs to be
measured, temperature measurement may be conducted directly through the
temperature-measuring holes on the meter body. If there is no temperature-measuring
hole on the meter body, it shall, according to the requirements of the flowmeter and
relevant stipulations, determine the measurement location of temperature. If there is
no special requirement, in terms of one-way measurement flowmeter, the location for
temperature measurement shall be set up at the downstream (3 ~ 5)D area (D signifies
internal diameter of pipeline) of the flowmeter; in terms of two-way measurement
flowmeter, the location for temperature measurement shall be set up at least 5D away
from the flowmeter. The influence of measurement error of the used thermometer on
the verification result shall be within 1/5 of the maximum allowable error of the
flowmeter.
7.1.1.5 When the pressure of fluid that flows through the flowmeter needs to be
measured, directly take pressure from pressure ports on the flowmeter body. If there
are no pressure ports on the flowmeter body, it shall, according to the requirements of
the flowmeter, determine the measurement location of pressure. If there are no special
requirements, the device shall install pressure meter at 10D area on the upstream side
of the flowmeter. The axes of the pressure ports shall be vertical to the axes of the
measuring pipe; the diameter shall be (4 ~ 12) mm. The influence of measurement
error of the used pressure meter on the verification result shall be within 1/5 of the
maximum allowable error of the flowmeter.
7.1.2 Fluid for verification
7.1.2.1 Universal conditions
(1) Fluid used for verification shall be single-phase gas or liquid. Use it to fill test
pipeline; its flow shall manifest no vortex.
(2) Fluid used for verification shall be clean; there shall be no visible particles or
fibers.
(3) Liquid flowmeter shall use liquid as the verification medium. Gas flowmeter
shall use gas as the verification medium. In addition, the physical parameters
(density and viscosity, etc.) of the verification medium and the actually used
medium shall be approximate.
7.1.2.2 Liquid used for verification
(1) The pressure of liquid used for verification on any point in the pipeline system
and the flowmeter shall be higher than the saturated vapor pressure. In terms
of easily vaporized liquid that is used for verification, there shall be certain
backpressure at the downstream of the flowmeter. The recommended
backpressure is 1.25 times of saturated vapor pressure of verification liquid
under the highest verification temperature.
(2) During each verification process of each flow point, the variation of liquid
temperature shall not exceed ± 0.5 °C.
(3) The liquid shall not be mingled with gas.
7.1.2.3 Gas used for verification
(1) In terms of flowmeter whose operating pressure is 0.4 MPa and above, the
pressure of gas in the pipeline shall be not lower than 0.1 MPa; try to maintain
the consistency with the actual operating conditions. In terms of flowmeter
whose operating pressure is below 0.4 MPa, pressure of gas in the pipeline
shall not be higher than 0.4 MPa; verification may be conducted under
atmospheric pressure.
(2) Impurities like free water or oil shall not exist; the grain size of solids like dust
shall be less than 5 μm.
(3) In terms of flowmeter whose accuracy grade is not lower than Grade 1.0, in
each verification process of each flow point, temperature variation of gas used
for verification shall not exceed ± 0.5 °C. In terms of flowmeter whose
accuracy grade is lower than Grade 1.0, in each verification process of each
flow point, temperature variation of gas used for verification shall not exceed
± 1 °C.
(4) When gas used for verification is natural gas, the quality of natural gas shall
comply with the requirements of Type-2 gas in GB 17820; the relative density
of natural gas shall be 0.55 ~ 0.80.
(5) When gas used for verification is natural gas, during the verification process,
gas component shall be relatively stable. The sampling of natural gas shall
comply with GB/T 13609; the composition analysis of natural gas shall comply
with GB/T 13610.
(6) During the verification process of each flow point, pressure fluctuation shall not
exceed ± 0.5%.
7.1.3 Verification environment conditions
7.1.3.1 Generally speaking, ambient temperature is (5 ~ 45) °C; humidity is (35 ~ 95) %
RH; atmospheric pressure is (86 ~ 106) kPa.
7.1.3.2 AC power supply voltage shall be (220 ± 20) V; power frequency shall be (50
± 2.5) Hz. Or, in accordance with the requirements of flowmeter, suitable AC power or
DC power may be used (for example, 24 V DC).
7.1.3.3 The external magnetic field shall be so small that its influence on flowmeter can
be neglected.
7.1.3.4 Mechanical vibration and noise shall be so small that its influence on flowmeter
can be neglected.
7.1.3.5 When flammable or explosive fluid, for example, natural gas, is used as the
medium for verification, all the verification devices and their auxiliary equipment, and
verification site shall comply with the requirements in GB 50251. All the equipment and
environment conditions must comply with relevant safety explosion-proof requirements
in GB 3836.
7.1.4 Installation conditions
7.1.4.1 The installation of flowmeter shall comply with the requirements in Appendix D.
7.1.4.2 During verification, in principle, all the components that constitute flowmeter
shall be submitted for verification.
7.1.5 Each measurement time shall be not less than the allowed shortest measurement
time of the device and the flowmeter being verified.
7.1.6 When the pulse output of the flowmeter being verified is adopted for verification,
the pulse count recorded in one verification shall not be less than 10 times of the
reciprocal of the absolute value of the maximum allowed error.
7.1.7 All the electrical apparatus used for verification shall be grounded in the same
point.
7.2 Verification Items and Verification Methods
7.2.1 Verification items
Verification items of the initial verification, subsequent verification and in-use
inspection are listed in Table 2.
Table 2 -- Table of Verification Items
Verification Items Initial Verification Subsequent Verification In-use Inspection
Product documents and
Appearance + + +
Air-tightness + + +
Flowmeter Parameters - - +
Reading Error + + -
Repeatability + + -
Flowmeter Factor Correction + + -
NOTE: “+” signifies items that need to be verified; “-” signifies items that do not need to be verified.
7.2.2 Product documents and appearance inspection
7.2.2.1 Inspect the product documents, which shall comply with the requirements in
Clause 6.1.
7.2.2.2 Use the method of visual inspection to inspect the appearance of flowmeter,
which shall comply with the requirements in Clause 6.2 and Clause 6.3.
7.2.3 Verification of reading error
7.2.3.1 Pre-operation inspection
Connect, initiate, pre-heat; in accordance with the method appointed in the instruction
of flowmeter, inspect the parameter setting of the flowmeter.
7.2.3.2 Air-tightness inspection
Conduct visual inspection to inspect the air-tightness of flowmeter, which shall comply
with the requirements in Clause 6.5.
7.2.3.3 Flowmeter shall operate within the range of 70% ~ 100% of the maximum
verification flow that can be reached; maintain for at least 5 min. Wait till the fluid
temperature, pressure and flow rate become stable, then, proceed to the official
verification.
7.2.3.4 Flow point control and verification factors
(1) Generally speaking, verification shall include the following flow points: qmin, qt,
0.40 qmax and qmax. In terms of flowmeter whose accuracy grade is not lower
than 0.5% and measuring range ratio is not larger than 20:1, add two flow
points: 0.25 qmax and 0.70 qmax. In terms of flowmeter whose accuracy grade
is superior to 0.5% and measuring range ratio is larger than 20:1, add one
verification point, whose flow is 0.1 qmax.
(2) When the device’s maximum verification flow cannot reach qmax, qmax may take
the maximum flow of the device. However, in terms of the maximum flow of
verification, fluid shall be not less than 10 qt; gas shall be not less than 4 qt.
(3) During the verification process, the deviation between each actual verification
flow rate of each flow point and the set flowrate shall not exceed ± 5% of the
set flow rate, or, shall not exceed ± 1% qmax; the corresponding fluid flow rate
of the minimum flow point shall not be less than the minimum flow rate
indicated on flowmeter’s nameplate.
(4) The times of verification of each flow point shall not be less than 3 times. In
terms of flowmeter whose type evaluation and accuracy grade are not lower
than Grade 0.5, the times of verification of each flow point shall be not less
than 6 times.
7.2.3.5 Verification procedure
(1) Regulate flow to the stipulated flow value. After it becomes stable, record the
initially indicated value of the standard and the flowmeter being verified.
Meanwhile, initiate the standard (or standard’s recording function) and the
flowmeter being verified (or the flowmeter’s output function).
(2) In accordance with the operating requirements of the device, operate for a
certain period of time. Meanwhile, stop the standard (or standard’s recording
function) and the flowmeter being verified (or the flowmeter’s output function).
(3) Record the final value indicated by the standard and the flowmeter being
verified.
(4) Respectively calculate the accumulative flow value or instantaneous flow rate
recorded by the flowmeter and the standard.
7.2.3.6 Calculation of reading error
(1) The relative reading error of single verification of flowmeter is:
Where,
Eij---relative reading error of flowmeter being verified in the jth verification in
the ith verification flow point, expressed in (%);
Qij---accumulative flow value displayed by flowmeter in the jth verification in
or
the ith verification flow point, expressed in (m3);
(Qs)ij---accumulative flow value when standard is converted into flowmeter
status in the jth verification in the ith verification flow point, expressed in
(m3);
qij---instantaneous flow rate value displayed by flowmeter in the jth verification
in the ith verification flow point; it may be an average value of
instantaneous flow rate values read in multiple times during a verification
process; expressed in (m3/h);
(qs)ij---instantaneous flow rate value when standard is converted into
flowmeter status in the jth verification in the ith verification flow point,
expressed in (m3/h).
When the standard displays accumulative flow:
Where,
t---time of the jth verification in the ith verification flow point, expressed in (s).
① In terms of liquid flowmeter, calculate (Qs)ij in accordance with the formula
below:
Where,
(Vs)ij---actual volume of liquid measured by standard in the jth verification in
the ith verification flow point, expressed in (m3);
β---volume expansion factor of verification liquid under the verification status,
expressed in (°C)-1;
θs, θm---liquid temperature at the standard and the flowmeter in the jth
verification in the ith verification flow point, expressed in (°C);
κ---compression factor of verification liquid under the verification status,
expressed in Pa-1;
ps, pm---fluid pressure respectively at the standard and the flowmeter in the
jth verification in the ith verification flow point, expressed in (Pa);
When the difference between θs and θm is less than 5 °C, and the difference
between ps and pm is less than 0.1 MPa, the formula above may be simplified
into:
When Gravimetric device is adopted for verification, the density (ρ1) of the
liquid needs to be measured. Meanwhile, in consideration of the influence of
air buoyancy with the density of (ρa), in accordance with the following
formula, convert the mass (Mij) displayed by electronic scale into the actual
volume (Vs)ij:
② In terms of gas flowmeter, calculate (Qs)ij in accordance with the formula
below:
Where,
Ts, Tm---gas thermodynamic temperature respectively at the standard and
the flowmeter in the jth verification in the ith verification flow point, expressed
in (K);
zs, zm---gas compression factor respectively at the standard and the
flowmeter in the jth verification in the ith verification flow point.
(2) The relative reading error of various verification flow points of flowmeter shall
be calculated in accordance with the formula below:
Where,
Ei---relative reading error of the ith verification flow point of flowmeter, expressed
in (%);
n---times of verification of the ith verification flow point;
Eij---relative reading error of the jth verification in the ith verification flow point of
flowmeter.
(3) The relative reading error of flowmeter is:
Where,
ǀEiǀmax---the maximum value of relative reading error of various verification
points in the high zone and the low zone of flowmeter.
The result shall comply with the requirements in 5.1.
7.2.4 Repeatability of flowmeter
When each flow point is repeatedly verified for n times, the repeatability of this flow
point shall be assessed in accordance with the following formula:
Where,
(Er)i---repeatability of the ith verification flow point.
The repeatability of the high zone and the low zone of flowmeter shall respectively be:
The result shall comply with the requirements in 5.2.
7.2.5 Meter factor correction
After verification, meter factor may be corrected in accordance with appropriate
methods. After the factor of a new flowmeter is written into flowmeter, respectively
select at least 1 flow point below and above qt for testing, so as to confirm the effect of
the correction. In addition, calculate the flowmeter factor adjustment amount
and . Then, write the previous flowmeter factor F0, the new flowmeter factor F and
the flowmeter factor adjustment amount into verification certificate.
7.3 Processing of Verification Result
Flowmeters that are qualified in the verification shall receive a verification certificate.
The requirements of the content of the verification certificate are shown in Appendix E.
Flowmeters that are disqualified in the verification shall receive a verification result
notification, which shall indicate the disqualified items. Flowmeters that receive in-use
inspection shall receive an inspection report.
7.4 Verification Cycle
Generally speaking, verification cycle shall not exceed 2 years. In terms of plug-in
flowmeter, if the flowmeter has self-diagnostic functions and can retain alarm records,
verification may be conducted once in every 6 years and in-use inspection shall be
conducted on the site every year.
Appendix A
Type Evaluation of Ultrasonic Flowmeter
A.1 Scope
It is applicable to type evaluation of ultrasonic flowmeters.
A.2 References
Through reference, the causes included in the following standards and regulations
become clauses of this Regulation.
JJF 1015-2002 General Norm for Pattern Evaluation and Pattern Approval of
Measuring Instruments;
JJF 1016-2002 The Rules for Drafting Program of Pattern Evaluation of Measuring
Instruments;
GB/T 2423.1-2001 Environmental Testing for Electric and Electronic Products - Part 2:
Test Methods - Tests A: Cold;
GB/T 2423.2-2001 Environmental Testing for Electric and Electronic Products - Part 2:
Test Methods - Tests B: Dry Heat;
GB/T 2423.3-2006 Environmental Testing for Electric and Electronic Products - Part 2:
Testing Methods - Test Cab: Damp Heat Steady State;
GB/T 2423.4-1993 Basic Environmental Testing Procedures for Electric and Electronic
Products: Test Db: Damp Heat, Cyclic;
GB/T 2423.10-1995 Environmental Testing for Electric and Electronic Products - Part
2: Testing Methods - Test Fc and Guidance: Vibration (sinusoidal);
GB 4208-1993 Degrees of Protection Provided by Enclosure (IP code);
GB/T 4857.2-2005 Packaging - Basic Tests for Transport Packages - Part 2:
Temperature and Humidity Conditioning;
GB/T 4857.5-1992 Packaging - Transport Packages - Vertical Impact Test Method by
Dropping;
GB/T 17626.2-2006 Electromagnetic Compatibility (EMC) - Testing and Measurement
Techniques - Electrostatic Discharge Immunity Test;
GB/T 17626.4-1999 Electromagnetic Compatibility (EMC) - Testing and Measurement
Techniques - Electrical Fast Transient/burst Immunity Test;
GB/T 17626.5-1999 Electromagnetic Compatibility (EMC) - Testing and Measurement
Techniques - Surge Immunity Test;
GB/T 17626.8-2006 Electromagnetic Compatibility (EMC) - Part 8: Testing and
Measurement Techniques - Power Frequency Magnetic Field Immunity Test;
GB/T 17626.11-1998 Electromagnetic Compatibility (EMC) - Testing and Measurement
Techniques - Voltage Dips, Short Interruptions and Voltage Variations Immunity Tests;
GB/T 17747.2-1999 Natural Gas - Calculation of Compression Factor - Part 2:
Calculation Using Molar - Composition Analysis;
GB/T 11062-1998 Natural Gas - Calculation of Calorific Values, Density, Relative
Density and Wobbe Index from Composition
Please make sure to adopt the currently valid version of the above-mentioned
references when this outline is put into effect.
A.3 Technical Information and Test Prototype Submitted by Applicant
A.3.1 The submitted technical information shall comply with the requirements in
Chapter 5 in JJF 1015.
A.3.2 In terms of wetted ultrasonic meters, flowmeter whose nominal diameter is not
more than 100 mm: choose 3 test prototypes; flowmeter whose nominal diameter is
more than 100 mm and not more than 300 mm: choose 2 test prototypes; flowmeter
whose nominal diameter is more than 300 mm, choose 1 test prototype. In terms of
clamp-on ultrasonic meters: choose 3 test prototypes.
A.3.3 In terms of ultrasonic flowmeter series of products for type evaluation, select 1/3
representative specification products including the minimum size for prototype testing.
A.3.4 If significant defects or deficiencies are found in the technical information review,
return the technical information and the prototype back to the applicant; request for
corrections.
A.4 Requirements of Legal Management
A.4.1 Unit of measurement
Flowmeter shall adopt legal unit of measurement. The preferred unit of flow
measurement is (m3/h); the preferred unit of volume is (m3); the preferred unit of
pressure is (MPa) or (kPa); the preferred unit of temperature is (°C).
A.4.2 Grade of accuracy (maximum allowable error)
The stipulations of the accuracy grade of flowmeter shall comply with the requirements
in Clause 5.1 in this Regulation.
A.4.3 Metrological mark and marking of measuring instrument
Metrological mark and marking of measuring instrument must be left on obvious parts
(such as nameplate, panel or header) of flowmeter. The nameplate and the mark must
be clearly identifiable, steady and reliable.
A.4.4 External structural design
In terms of flowmeter that does not allow users’ self-adjustment, sealed structural
design shall be adopted, or, a location of affixed seal must be retained. Any artificial
mechanical interference that would affect the accuracy of measurement will leave
permanent tangible damage traces on flowmeter, or the protective mark or safeguard
mark of verification.
A.4.5 Installation marking
On the flowmeter body, there shall be marking of installation instruction.
A.4.6 If errors or content that does not comply with the requirements are found in the
review of the technical information, timely inform the applicant and request for
corrections.
A.5 Requirements of Measurement
A.5.1 The main metrological performance of flowmeter is: flow range, accuracy grade
(maximum allowable error), operating pressure range and operating temperature
range. These contents shall be clearly indicated on the external part of flowmeter.
Other metrological performance shall be stated in the instruction for use.
A.5.2 The maximum allowable error and measurement repeatability of flowmeter shall
comply with the stipulations of Clause 5.1 and Clause 5.2 in this Regulation.
A.5.3 Zero-flow reading
A.5.3.1 Gas flowmeter
In terms of each acoustic path, zero-flow reading of gas flowmeter shall be not more
than 12 mm/s.
A.5.3.2 Liquid flowmeter
In terms of each acoustic path, zero-flow reading of liquid flowmeter shall be not more
than 4 mm/s.
A.5.4 Except from the listed test items, in accordance with prototype product standards
and technical requirements of type evaluation, test items can be added.
A.6 Technical Requirements
A.6.1 Product documents and appearance
A.6.1.1 The submitted technical information shall comply with the requirements of
Clause 6.1 in this Regulation. Except from this, there shall also be: photos of prototype;
product standards (including inspection methods); test reports provided by
manufacturers or technical institutions.
A.6.1.2 The appearance of flowmeter shall comply with the requirements of Clause 6.2
and Clause 6.3 in this Regulation.
A.6.1.3 The air-tightness of flowmeter shall comply with the requirements of Clause
6.5 in this Regulation.
A.6.2 Impact of safety performance
A.6.2.1 Explosion-proof performance
Flowmeter that is applied to explosive gas atmosphere shall obtain explosion-proof
test report and explosion-proof certificate issued by a nationally appointed explosion-
proof inspection institution.
Flowmeters that are applied to different purposes shall comply with the requirements
of corresponding protection grade in GB 4208; obtain protection grade certificate
issued by a nationally certified institution.
A.6.2.2 Resistance to internal pressure
Flowmeter body shall be able to endure pressure resistance strength test under the
test pressure that is 1.5 times of the maximum operating pressure for 5 min; manifest
no damage or leakage.
A.6.2.3 Insulation resistance
The value of insulation resistance between flowmeter’s power supply terminal and
grounding terminal; between output terminal and grounding terminal shall be not less
than 20 MΩ.
A.6.2.4 Dielectric strength
Flowmeter’s power supply terminal and grounding terminal; output terminal and
grounding terminal shall be able to endure test pressure under the frequency of 50 Hz
and the pressure listed out in Table A.1, maintain for 1 min; there shall be no
phenomena like breakdown or arcing.
A.6.3 Flow computer’s function check
A.6.3.1 Flow computer shall have self-diagnostic functions, such as: automatic gain
control (AGC), signal strength and reception rate, signal to noise ratio, etc. The normal
range of the various indexes shall be provided in the instruction for use.
A.6.3.2 Flow computer shall have the functions of data storage, such as: storage
capacity and format, etc.;
A.6.3.3 Flow computer shall have the functions of flow accumulation, such as: flow
accumulation of day, month and year;
A.6.3.4 Flow computer shall have the function of historical data query.
A.6.3.5 Flow computer shall have the function of computation; standards adopted in
the computation and the setting of standard reference conditions shall be provided in
the instruction for use.
A.6.3.6 Flow computer shall have the function of output, for example, the display of
information like flow, flow rate and acoustic speed;
A.6.3.7 Flow computer shall have the function of confidentiality; implement multi-level
password management.
Table A.1 -- Requirements of Dielectric Strength
A.6.4 Auxiliary function check
A.6.4.1 Power undervoltage protection
Data in flowmeter shall be able to be maintained on a long-term basis; be free from the
influence of low voltage and battery replacement, etc.
A.6.4.2 Protective function
Flowmeter shall have a reliable capability of resisting abnormal external operations.
When there are abnormal operations or external interferences, flowmeter shall be able
to have protective reaction, or, be free from their influence.
A.6.4.3 Other functions
Power Supply Holding Time Test Voltage and Frequency
AC
DC
In accordance with flowmeter product standards and the technical requirements of type
evaluation, determine test items and test requirements, such as: output, software,
inspection and supervision function, and alarm, etc.
A.6.5 Environmental requirements
A.6.5.1 Low-temperature storage
Low-temperature storage shall comply with the requirements of “Test Ad” in GB/T
2423.1.
A.6.5.2 High-temperature storage
High-temperature storage shall comply with the requirements of “Test Bd” in GB/T
2423.2.
A.6.5.3 Damp heat steady state storage
Damp heat steady state storage shall comply with the requirements of “Test Ca” in
GB/T 2423.3.
A.6.5.4 Cyclic damp heat storage
Cyclic damp heat storage shall comply with the requirements of “Test Db” in GB/T
2423.4.
A.6.6 Mechanical vibration
A.6.6.1 Sinusoidal vibration test
Sinusoidal vibration test shall comply with the requirements of “Test Fc” in GB/T
2423.10.
A.6.6.2 Transport package dropping test
In terms of flowmeter being tested, put its transport package in the state of ready-to-
be transported. In accordance with the stipulations of Condition 6 in Clause 2.1 in GB/T
4857.2, conduct pre-treatment for 4 h. In accordance with the requirements in Clause
3.5 in GB/T 4857.5, tilt one side of the bottom of the transport package to the height of
25 mm. Then, let it freely drop to a rigid ground. Randomly take 4 surfaces; each
surface shall drop once. After the test, the prototype shall manifest no breakage or
distortion on the surface; the electric circuit part shall manifest no phenomena like open
welding or de-soldering.
A.6.7 Power supply
A.6.7.1 Power supply voltage variation test
Under the state of power supply, place it for sufficient time. Respectively adjust the
power supply voltage to ± 10% of normal voltage; the meter shall be normally
functioning.
A.6.7.2 DC reverse protection
In terms of flowmeter under two-wire DC power supply, between power supply
terminals, reversely apply 1.1 times of the nominal voltage value, maintain for 1 min;
there shall be no damage.
A.6.8 Electromagnetic compatibility
A.6.8.1 Electric transient burst immunity test
Conduct the test in accordance with GB/T 17626.4; test grade shall be Grade 2. During
the test process, prototype is allowed to have errors. 30 s after the test is completed,
re-start the prototype, and it shall be normally functioning.
A.6.8.2 Electrostatic discharge immunity test
Conduct the test in accordance with GB/T 17626.2; test grade shall be Grade 3. During
the test process, prototype shall be normally functioning.
A.6.8.3 Power frequency magnetic field immunity test
Conduct the test in accordance with GB/T 17626.8; test grade shall be Grade 3. During
the test process, prototype shall be normally functioning.
A.6.8.4 Surge immunity test
Conduct the test in accordance with GB/T 17626.5; test grade shall be Grade 2. During
the test process, prototype is allowed to have errors. After the test is completed, the
prototype shall be able to automatically recover.
A.6.8.5 Power interruption test
Conduct the test in accordance with test grade 0%UT in GB/T 17626.11.
A.6.9 After flowmeter receives the above-mentioned tests, re-measure the reading
error in the flow points qmin, qt and 0.4 qmax, which shall still comply with the
requirements of Clause 5.1 in this Regulation.
A.7 Conditions and Methods of Type Evaluation
A.7.1 Conditions of type evaluation
A.7.1.1 Standard flow device that is used in type evaluation test shall comply with the
requirements in Clause 7.1.1 in this Regulation.
A.7.1.2 Test medium that is used in type evaluation test shall comply with the
requirements in Clause 7.1.2 in this Regulation.
A.7.1.3 Environmental conditions in type evaluation test shall comply with the
requirements in 7.1.3 in this Regulation.
A.7.2 Requirements of legal management
In accordance with the requirements in Clause A.4 in this Regulation, conduct visual
inspection item by item.
A.7.3 Product documents and appearance inspection
Conduct visual inspection, which shall comply with the requirements in A.6.1.1, A.6.1.2
and A.6.2.1.
A.7.4 Safety performance impact test
A.7.4.1 Resistance to internal pressure
Slowly inject fluid into flowmeter to 1.5 times of the maximum operating pressure;
maintain for 5 min. Then, slowly relieve the pressure. In the pressure-holding stage,
the indicated pressure shall not drop. The various parts of meter body and the
connecting parts shall have no breakage or leakage.
A.7.4.2 Air-tightness
Slowly inject gas into flowmeter to the maximum operating pressure. The various parts
of the meter body and the connecting parts shall have no leakage.
A.7.4.3 Insulation resistance
Conduct insulation resistance test right after damp heat steady state storage test is
completed. Use megameter to measure the insulation resistance between flowmeter’s
power supply terminal and grounding terminal; between output terminal and grounding
terminal, which shall satisfy the requirements in A.6.2.3.
A.7.4.4 Dielectric strength
Conduct dielectric strength test right after insulation resistance test is completed. It
shall comply with the requirements in A.6.2.4.
A.7.5 Flow computer
In accordance with the requirements of flowmeter instruction, conduct inspection item
by item. The result shall comply with the requirements in A.6.3.
A.7.6 Metrological performance test
A.7.6.1 Zero-flow reading
When test medium is gas or high-pressure water, connect both ends of flowmeter to
blind flange. Then, use the mode of suction or replacement to exhaust all the air in the
flowmeter. Push in pure water or nitrogen; the pressure shall be not lower than the
lowest pressure of normal operation of ultrasonic transducer. When test medium is
atmospheric pressure liquid, the flowmeter can be completely immersed into liquid in
a vertical direction. In this measurement chamber, pressure and temperature shall
maintain stable. The flow rate measurement of each acoustic path shall maintain 30 s
of observation and recording. The result shall comply with the requirements in Clause
A.5.3.
A.7.6.2 Adopt the method of visual inspection to check flowmeter’s air-tightness, which
shall comply with the requirements in A.6.1.3.
A.7.6.3 In accordance with 7.2.3.4 in this Regulation, select flow points and determine
the times of verification.
A.7.6.4 In accordance with 7.2.3.5 in this Regulation, conduct the test.
A.7.6.5 In accordance with 7.2.3.6 in this Regulation, calculate flowmeter’s relative
reading error.
A.7.6.6 In accordance with the method in 7.2.4 in this Regulation, calculate flowmeter’s
measurement repeatability.
A.7.7 Climatic environmental test
A.7.7.1 Low-temperature test
In accordance with the requirements in A.6.5.1, place flowmeter under low-
temperature (-40 °C) condition for 2 h; recovery time: 2 h. The temperature variation
rate of warming and cooling shall not exceed 1 °C/min. In terms of air humidity, it is
requested that the whole test period shall avoid condensate water.
A.7.7.2 High-temperature test
In accordance with the requirements in A.6.5.2, place flowmeter under high-
temperature (55 °C) condition for 2 h; recovery time: 2 h. The temperature variation
rate of warming and cooling shall not exceed 1 °C/min. In terms of air humidity, it is
requested that the whole test period shall avoid condensate water.
A.7.7.3 Damp heat steady state test
In accordance with the requirements in A.6.5.3, place flowmeter under the condition
(temperature: 30 °C; relative humidity: 93%) for 48 h; recovery time: 2 h. This process
shall also avoid condensate water.
A.7.7.4 Cyclic damp heat test
In accordance with the requirements in A.6.5.4, place flowmeter in a constant
temperature and humidity chamber. The temperature shall alternatively change
between 25 °C and 55 °C. In the lower limit of the temperature, maintain above 95%
relative humidity; in the upper limit of the temperature, maintain 93% relative humidity.
When temperature rises, the surface of the electronic device might generate
condensate water. Test time shall be two 24 h cycles; each cycle shall comply with the
stipulated procedures in GB/T 2423.4.
A.7.8 Mechanical environment test
A.7.8.1 Sinusoidal vibration test
In accordance with the requirements in A.6.6.1, accelerated speed shall be 2 m/s2. At
the frequency multiplication of 1/min, within the vibration frequency of (10 ~ 150) Hz,
conduct sinusoidal vibration test. Respectively vibrate in three axial directions that are
mutually vertical.
A.7.8.2 Transport package drop test
Conduct the test in accordance with the requirements in A.6.6.2. After the test, check
the damage of the package; inspect the sample being tested.
A.7.9 Power supply
A.7.9.1 Power supply voltage variation test
Conduct the test in accordance with the requirements in A.6.7.1.
A.7.9.2 DC reverse protection test
Conduct the test in accordance with the requirements in A.6.7.2
A.7.10 Electromagnetic compatibility test
A.7.10.1 Electric transient burst immunity test
Conduct the test in accordance with the requirements in A.6.8.1. Pulse rise time is 1
ns. Pulse duration is 50 ns.
A.7.10.2 Electrostatic discharge immunity test
Conduct the test in accordance with the requirements in A.6.8.2. Test for 10 times.
There shall be certain time interval between electrostatic discharges.
A.7.10.3 Power frequency magnetic field immunity test
Conduct the test in accordance with the requirements in A.6.8.3. Apply continuous
magnetic field to prototype. Test field strength is 10 A/m.
A.7.10.4 Surge immunity test
Conduct the test in accordance with the requirements in A.6.8.4. In selected points, at
least add 5 times of positive polarity and 5 times of negative polarity. Repetition rate is:
do not exceed 1 time in every minute. The applied surge strength is: line-line
interference: 0.5 kV, duration: 50 μs; line-ground interference: 1.0 kV, duration: 50 μs.
A.7.10.5 Power interruption test
In accordance with the requirements in A.6.8.5, under the state of normal power supply,
interrupt power supply for 10 times; the time interval shall be at least 10 s.
A.7.11 Metrological performance re-test
In accordance with the requirements in A.6.9, respectively verify 3 times in each point.
A.7.12 Determination principles
A.7.12.1 The test process of prototype shall satisfy the requirements from A.6.2 to
A.6.8 in this Regulation.
A.7.12.2 Prototype shall not manifest program disorder or functional failure. Before
and after the applied interference, parameters and historical data in the prototype shall
have no changes.
A.8 Determination of Type Evaluation Result
A.8.1 Items of type evaluation are divided into primary items and non-primary items.
The items in Clause A.6.1.2 are non-primary items, and the others are primary items.
A.8.2 When a single item of a prototype is disqualified in type evaluation, this item shall
be determined as disqualified.
A.8.3 When more than one (including one) primary items are disqualified in type
evaluation, then, the result of type evaluation shall be determined as disqualified.
A.8.4 When the type evaluation result of one specification in a series of products is
disqualified, then, the result of type evaluation of this series of products shall be
disqualified.
Appendix B
Special Requirements of On-site Verification
This Appendix is applicable to on-line verification on the site of usage of ultrasonic
flowmeters. This Appendix is not applicable to type evaluation or initial verification.
B.1 Requirements of Standard Device
B.1.1 Flow standard shall have complete legal files.
B.1.2 The measurement range of flow standard shall be able to cover the on-site flow
range of the flowmeter being verified.
B.1.3 Standard flowmeter shall be verified in accordance with a certain cycle and have
valid verification certificate. Standard flowmeter shall have satisfying recurring
performance.
B.1.4 The uncertainty of the measurement result of flow standard shall be not larger
than 1/3 of the absolute value of the maximum allowable error of the flowmeter being
verified.
B.1.5 Standard devices used in explosion-proof areas shall have corresponding
explosion-proof certificate.
B.2 Installation Conditions of Flow Standard
B.2.1 Flow standard shall adapt to variations of flow, pressure and temperature, and
the type of the medium being tested. If necessary, protective equipment shall be
installed, so as to guarantee that flow standard can normally function under the
designed conditions.
B.2.2 The installation of flow standard shall satisfy the lowest requirements of relevant
national standards, or, be consistent with flow standard manufacturer’s requirements
(manufacturer’s requirements shall be not lower than relevant national standards).
B.2.3 The distance between flow standard and flowmeter being verified shall be as
short as possible, as long as they do not cause mutual interference. The difference
between the diameter of connecting pipeline and the diameter of the standard
flowmeter shall be within 1%, so as to guarantee the flow profile that is required by the
standard flowmeter in the verification.
B.2.4 Temperature and pressure transmitter installed on the pipe sections of flow
standard shall satisfy the stipulations of 7.1.1.4 and 7.1.1.5 in this Regulation.
B.3 Verification Methods
B.3.1 The inspection before operation shall comply with the requirements in 7.2.3.1 in
this Regulation.
B.3.2 Verification points
B.3.2.1 Under general circumstances, verification points shall select: the minimum flow
of flowmeter (qmin), transition flowrate (qt), the maximum flow (qmax) that the system can
reach; 2 equant flow points in the middle of transition flowrate and qmax.
B.3.2.2 If the system cannot reach (qmin), then, the minimum flow that the system can
reach needs to be measured. If the system’s attainable range is less than 5:1, then,
within the actual operating flow range of the flowmeter, select at least 3 flow points.
B.3.2.3 If the system cannot implement flow regulation and the flowmeter is used in
fixed points, then, verification points may choose actually used flow points; the
verification certificate shall indicate: use in fixed points.
B.3.2.4 During a test process, the maximum variation of instantaneous flow rate shall
not exceed 5%.
B.3.3 Times of verification: comply with 7.2.3.4.
B.4 On-site verification and its conditions shall be indicated in the verification certificate.
B.5 The remaining shall comply with the stipulations in this Regulation.
Appendix C
In-use Inspection
In-use inspection of ultrasonic flowmeter is used to inspect the reliability of the
metrological performance of flowmeter within the verification cycle after the verification
on actual flow device is completed. In-use inspection has two methods: one is to on-
line adopt 1 standard flowmeter for comparison; the other is to take the comparison of
sound speed as the basis to conduct on-line inspection of flowmeter.
C.1 Technical Requirements
C.1.1 Time arrangement of inspection
Within 1 month after the flowmeter to be inspected is installed on pipeline and put into
use, conduct the first inspection. After that, conduct the inspection in accordance with
the cycle of at least once a year.
C.1.2 In in-use inspection of flowmeter, the previous inspection report of the flowmeter
must be taken along.
C.1.3 Check whether flowmeter factor changes after the previous verification.
C.2 Standard Flowmeter Comparison Method
C.2.1 Requirements of standard flowmeter
C.2.1.1 Standard flowmeter shall comply with the requirements in B.1.2 and B.1.4 in
the Appendix of this Regulation.
C.2.1.2 Standard flowmeter shall have satisfying recurring performance; its accuracy
grade shall be not lower than the accuracy grade of the flowmeter being inspected.
C.2.2 Installation conditions of standard flowmeter
Installation conditions of standard flowmeter shall comply with the requirements in B.2
in the Appendix of this Regulation.
C.2.3 Inspection method
Operating procedure is the same as B.3 of this Regulation.
C.2.4 Inspection result calculation
C.2.4.1 Measurement deviation
In comparison with standard flowmeter, the measurement deviation of flowmeter is:
Where,
ǀEiǀmax---the maximum value in the measurement deviation of various inspection points
of flowmeter;
Fi---the average value of flowmeter factor in the ith inspection point obtained in this
inspection;
F0i---the average value of flowmeter factor in the ith inspection point obtained in the first
inspection.
The computing method of flowmeter factor is as follows:
Where,
Qsij---value indicated by standard flowmeter in the jth inspection in the ith inspection
point;
Qij---value indicated by flowmeter being verified in the jth inspection in the ith inspection
point;
Fij---flowmeter factor in the jth inspection in the ith inspection point.
C.2.4.2 Repeatability
Flowmeter’s repeatability shall be calculated in accordance with 7.2.4.
C.2.5 Result processing
If measurement deviation (E) and repeatability of flowmeter do not exceed the
corresponding allowable value of the accuracy grade of the flowmeter, then, the result
shall be determined as qualified; the flowmeter may continue to be used. Otherwise,
the result shall be determined as disqualified; the flowmeter shall be submitted for
inspection.
C.3 Sound Speed Inspection Method
C.3.1 Standard equipment and installation conditions of gas ultrasonic
flowmeter
C.3.1.1 The adopted standard equipment includes: online chromatographic analyzer,
sampler; thermometer; pressure meter; calculation software.
C.3.1.2 The technical performance of the chromatographic analyzer shall comply with
GB/T 13610-2003; the accuracy of measurement shall reach 0.05%. The selection and
installation of chromatographic analyzer shall satisfy manufacturer’s technical
requirements.
C.3.1.3 The selection and installation of the sampling system shall satisfy GB/T 13609-
1999.
C.3.1.4 Temperature and pressure transmitter shall be installed near sampling points.
The installation of temperature and pressure transmitter shall satisfy the requirements
of 7.1.1.4 and 7.1.1.5 in this Regulation. The accuracy of pressure transmitter shall be
superior to 0.1%; the accuracy of temperature transmitter shall be superior to 0.1 °C.
C.3.1.5 Calculation software shall comply with AGA Report No. 10 and be approved
by metrological department.
C.3.1.6 Analyze the various components of pipeline gas listed out in Table C.1. When
the conditions allow, more components may be analyzed, so as to guarantee the
accuracy of the final calculation result.
Table C.1 -- Main Components of Natural Gas and Universal Range
C.3.2 Standard equipment and installation conditions of liquid ultrasonic
flowmeter
C.3.2.1 The adopted standard equipment includes: sound speed measurement
standard device; thermometer; pressure meter; calculation software.
C.3.2.2 Sound speed measurement standard device is a pair of ultrasonic transducers;
the distance between them is precisely measured and changeless.
C.3.2.3 Immerse sound speed measurement standard device into the fluid. The
temperature and pressure of the fluid shall be consistent with the fluid in the pipeline.
C.3.3 Operating conditions of standard equipment
C.3.3.1 All the standard equipment shall have a valid verification certificate.
C.3.3.2 The uncertainty introduced by standard equipment shall not be more than the
repeatability of the flowmeter being verified.
C.3.3.3 The measurement range of the standard equipment shall be able to satisfy the
full-range inspection requirements of the flowmeter being verified.
C.3.4 Inspection methods
Name Universal Range NOTE
Reference condition:Relative Density
Methane
Ethane
Propane
Butane
Pentane
Hexane +
Nitrogen
Carbon Dioxide
Carbon Monoxide
Argon
Oxygen
Water
Hydrogen Sulfide
C.3.4.1 Pre-operation inspection: connect, initiate, pre-heat; inspect in accordance
with the method appointed in the instruction of standard equipment; confirm whether
the parameter setting of all the standard equipment is correct.
C.3.4.2 Mechanical inspection: in accordance with the verification regulation and
national standard (or manufacturer’s enterprise standard), inspect the installation and
pipe diameter of the flowmeter to be verified on the site; conduct other mechanical and
electronic testing, so as to confirm that the flowmeter is correctly installed.
C.3.4.3 Flowmeter status inspection
C.3.4.3.1 Inspection of alarm files
Flowmeter shall have fault alarm function and record, including the time, type and
status record of fault alarm, etc. Inspect the alarm records. Confirm that there are no
alarms caused by flowmeter itself but sufficient to trigger metrological errors.
C.3.4.3.2 Signal inspection
Manufacturer shall provide the following diagnostic measurement data through
computer communication or on-site display; inspect the following indexes and compare
them with the data of the previous inspection; the deviation shall be within the allowable
range in the product instruction. If excessive deviation exists, the flowmeter shall be
submitted for inspection.
a. Gain value of each acoustic path signal, namely, strength of signal sent out
(received) by the probe that is installed on the flowmeter body;
b. Percentage of received signal of each acoustic path;
c. Signal to noise ratio of each acoustic path.
C.3.4.4 Inspection of sound speed measurement
C.3.4.4.1 Flow points of inspection
Under general circumstance, flow points of inspection shall select: the minimum
flowrate of flowmeter, or, the minimum flowrate that the system can reach (qmin),
transition flowrate (qt), the maximum flow (qmax) that the system can reach; 1 ~ 2 equant
flow points in the middle of transition flowrate and qmax.
If the system cannot implement flow regulation and the flowmeter is used in fixed points,
then, inspection flow points may choose actually used flow points; the inspection report
shall indicate: use in fixed points.
C.3.4.4.2 Times of inspection point: comply with 7.2.3.4.
C.3.4.4.3 Operating procedures
(1) Adjust the flow to the stipulated flow value; wait till it becomes stable.
Meanwhile, conduct sampling analysis, sound speed measurement and
flowmeter output record; record the determination result of the standard
equipment and the equipment being inspected.
(2) Output of equipment being inspected
Manufacturer shall provide the following diagnostic measurement data through
RS-232, RS-485 or on-site display:
a. Instantaneous sound speed value of each acoustic path of the flowmeter
being inspected;
b. Within the sampling ......
(Release/modified date: 2019-11-30 / 2019-12-03. Wayne Zheng et al.)
https://www.chinesestandard.net/PDF.aspx/JJG1030-2007