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JJG 1114-2015 PDF in English


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JJG 1114-2015: PDF in English

JJG 1114-2015
JJG
NATIONAL METROLOGICAL VERIFICATION REGULATION
OF THE PEOPLE’S REPUBLIC OF CHINA
Liquefied Natural Gas Dispensers
ISSUED ON: JUNE 15, 2015
IMPLEMENTED ON: SEPTEMBER 15, 2015
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China
Table of Contents
Introduction ... 5 
1 Scope ... 6 
2 Normative references ... 6 
3 Terms and units of measurement ... 6 
3.1 Terms ... 6 
3.2 Units of measurement ... 8 
4 General ... 9 
4.1 Construction ... 9 
4.2 Principle ... 9 
5 Metrological performance requirements ... 10 
5.1 Maximum allowable error ... 10 
5.2 Repeatability ... 10 
5.3 Flow range ... 10 
5.4 Minimum quality variable ... 10 
5.5 Payment amount error ... 10 
6 General technical requirements ... 10 
6.1 Appearance and accompanying documents ... 10 
6.2 Error adjustment ... 11 
6.3 Seal settings ... 11 
6.4 Safety functions ... 12 
7 Control of measuring instruments ... 12 
7.1 Verification conditions ... 12 
7.2 Verification items and methods ... 13 
7.3 Processing of verification results ... 21 
7.4 Verification cycle ... 21 
Appendix A Cryogenic liquids flow standard facilities by weighing method ... 22 
Appendix B Information format of verification certificate/verification result
notification and original record ... 28 
Verification Regulation of Liquefied Natural Gas
Dispensers
1 Scope
This Regulation applies to the initial verification, subsequent verification and
in-service inspection of liquefied natural gas (LNG) dispensers (hereinafter referred
to as dispensers).
2 Normative references
GB/T18442.1, Static vacuum insulated cryogenic pressure vessels - Part 1: General
requirements
GB/T 19204, General characteristics of liquefied natural gas
GB/T 20368, Production, storage and handling of liquefied natural gas (LNG)
GB/T 25986, Filling device of natural gas vehicles
GB 50156, Technical standard of fuelling station
OIML R81:2006(E), Dynamic measuring devices and systems for cryogenic liquids
For dated references, only the dated version applies to this Regulation; for undated
references, the latest edition (including all amendments) applies to this Regulation.
3 Terms and units of measurement
3.1 Terms
3.1.1 Liquefied natural gas (LNG) dispensers
A complete measuring system of LNG semi-invariant – providing LNG filling
service – which generally consists of cryogenic flowmeter, control valve, dispenser
nozzle, reclaiming nozzle, filling hose, reclaiming hose, as well as electronic
computer and ancillary devices.
3.1.2 LNG gas vessel
A vacuum insulated cryogenic pressure vessel used for storing and supplying LNG
fuel, of which the technical indicators shall meet the requirements of GB/T 18442.1.
3.1.3 Filling receptacle
A connecting part, after being connected with the dispenser nozzle, for filling LNG
fuel to the LNG gas vessel.
3.1.4 Reclaiming receptacle
A connecting part, after being connected with the reclaiming nozzle, used to reclaim
the residual gas in the LNG gas vessel.
3.1.5 Circulation receptacle
A connecting part on the gas dispenser used, after being connected with the
dispenser nozzle, for the pre-cooling circulation.
3.1.6 Dispenser nozzle
A special tool for manual operation on the gas dispenser for connecting the filling
receptacle or the circulation receptacle, which shall meet the requirements of GB/T
25986.
3.1.7 Reclaiming nozzle
A special tool for manual operation on the gas dispenser for connecting the
reclaiming receptacle, which shall meet the requirements of GB/T 25986.
3.1.8 Breakaway coupling valve
A special protection device on the gas dispenser, which is installed on the filling
hose and the reclaiming hose of the gas dispenser, and can be broken into two
sections under the action of the rated pull-out force.
3.1.9 Emergency shutdown device
A special protection device on the gas dispenser, which, after being manually
triggered in an emergency, can execute the corresponding shutdown logic, cut off or
isolate the LNG fuel source, and shut down the equipment that will aggravate and
expand the accident due to continued operation. It is generally located at an obvious
location of the gas dispenser.
3.1.10 Electronic computer
A calculation and control device of the gas dispenser, which can receive the flow
electric signal transmitted by the flow meter and the pressure electric signal
transmitted by the pressure sensor, etc., and calculate according to the set parameters;
can carry out data transmission and display operations, and automatically judge and
control the flow of the fluid; has the functions of returning to zero, indicating the
payment amount, etc., and can also realize the adjustment of the measurement error.
refilling. The electronic computer of the gas dispenser automatically controls the gas
filling process, and calculates according to the flow signal output by the flowmeter.
The mass of LNG filled into the gas vessel is the difference between the
measurement value of the liquid-phase flowmeter and the measurement value of the
gas-phase flowmeter (when the gas dispenser is not connected to the reclaiming
pipeline, the measurement value of the gas-phase flowmeter is zero), and the panel
of the gas dispenser displays the final measurement value.
For the gas dispenser used for trade settlement, a gas-phase flow meter must be
installed in the reclaiming pipeline to measure the residual gas in the gas vessel
recycled.
5 Metrological performance requirements
5.1 Maximum allowable error
The maximum allowable error of the gas dispenser is ±1.5%.
5.2 Repeatability
The measurement repeatability of the gas dispenser does not exceed 0.5%.
5.3 Flow range
The mass flow rate of the gas dispenser is less than or equal to 80 kg/min, and the
range ratio is not less than 4:1.
5.4 Minimum quality variable
The minimum quality variable of the gas dispenser shall not be greater than 0.01 kg.
5.5 Payment amount error
The payment amount displayed on the gas dispenser panel shall not be greater than
the calculated payment amount (the product of the unit price and the displayed
value).
6 General technical requirements
6.1 Appearance and accompanying documents
6.1.1 Appearance
6.1.1.1 The nameplate and markings of the gas dispenser shall be clear and reliable.
6.1.1.2 The connectors of the gas dispenser must be firm and reliable, and shall not
loosen or fall off due to vibration.
6.1.2 Accompanying documents
The gas dispenser shall be provided with the factory inspection certificate and the
instruction manual, which shall give the technical requirements, installation
conditions, usage methods, safety protection measures and the like.
6.1.3 Markings and nameplate
6.1.3.1 There shall be obvious safety and operation markings on the dispenser.
6.1.3.2 The nameplate of the gas dispenser generally indicates the following
contents:
1) Manufacturer’s name (trademark), product name and model specifications;
2) Date of manufacture and serial number;
3) Marking and number of the license for manufacturing measuring instruments;
4) Applicable medium, flow range, accuracy grade or maximum allowable error;
5) Applicable ambient temperature range, maximum working pressure, power
supply voltage;
6) Explosion-proof grade, explosion-proof identification and explosion-proof
certificate number, etc.
6.1.3.3 For gas dispensers with two or more nozzles, the number of the dispensers
shall be marked.
6.1.4 Cryogenic flowmeter
The cryogenic flowmeter used in the gas dispenser shall have clear nameplate and
complete identification; the measurement accuracy grade shall not be lower than 0.5;
the flow range, temperature range, pressure range, and use medium shall meet the
requirements of the gas dispenser.
6.2 Error adjustment
The gas dispenser shall have the function of adjusting the measurement error. For
important parameters that can change the metrological performance, mechanical or
electronic seals shall be used to ensure that the parameters of the gas dispenser
cannot be changed at will.
6.3 Seal settings
6.3.1 The error adjustment device or key components shall be equipped with
protective devices with mechanical seals, such as cryogenic flowmeter, electronic
standard facilities by weighing method (Appendix A) for on-site verification of the
gas dispenser.
7.1.1.2 The expanded uncertainty of the verification device (including factor k=2)
shall not be greater than 1/3 of the absolute value of the maximum allowable error of
the tested gas dispenser.
7.1.1.3 The verification device shall be equipped with a valid verification or
calibration certificate, meet the explosion-proof requirements, and have an
explosion-proof certificate within the validity period; the master standard shall be a
cryogenic flowmeter, of which the accuracy grade shall not be lower than 0.15, and
the pressure range and flow range shall be compatible with the gas dispenser to be
inspected; the ancillary devices (such as pressure gauge, safety valve) of the
verification device shall be provided with verification certificate or test report within
the validity period.
7.1.1.4 The pipelines and valves where LNG is stored and flows through shall meet
the design requirements for low temperature pipelines.
7.1.2 Verification medium
The verification medium shall be LNG, which shall fill the pipelines and flow meters;
the gas characteristics shall be in accordance with the provisions of GB/T 19204.
7.1.3 Gas release
The gas release after the verification shall comply with the regulations on natural gas
release in GB/T 20368 and GB 50156.
7.1.4 Verification environment
7.1.4.1 Ambient temperature: -25 ℃ ~ 55 ℃.
7.1.4.2 Relative humidity: 35% ~ 95%.
7.1.4.3 Atmospheric pressure: 86 kPa ~ 106 kPa.
7.1.4.4 Power supply voltage: voltage (220±22) V, frequency: (50±1) Hz.
7.2 Verification items and methods
7.2.1 Verification items
See Table 1 for the items of the initial verification, subsequent verification and
in-service inspection.
value of the verification device at the same time. Use Formula (2) to
calculate the relative error Eij of a single measurement indication value of
the gas dispenser:
Where:
Eij – relative error of a single measurement indication value of the jth
measurement at the flow point qi, %;
(mJ)ij – the accumulative flow indication value displayed on the gas
dispenser panel during the jth measurement at the flow point qi, kg;
(mB)ij – the accumulative flow indication value of the verification device
during the jth measurement at the flow point qi, kg.
7.2.6.5 Maximum allowable error
1) After the three measurements at the flow point qi, take the average value of the
relative errors of the three indication values as the indication error Ei at the
flow point. See Formula (3).
Where:
Ei – indication error at the flow point qi, %;
n – measurement times, n=3.
2) Take the maximum absolute value of the indication error, when the flow point
q1 and q2 are subject to separate verification of the liquid-phase flowmeter and
the flow point q1 is subject to whole machine verification, as the indication
error of the gas dispenser.
3) The maximum allowable error of the gas dispenser shall meet the requirements
of 5.1.
7.2.6.6 Repeatability
1) The repeatability Er is calculated by Formula (4):
Where:
(Er)i – measurement repeatability at the flow point qi, %;
Ei max – the maximum value of relative error of a single measurement
indication value at the flow point qi, %;
Ei min – the minimum value of relative error of a single measurement indication
value at the flow point qi, %;
dn – range coefficient (when the number of measurements is 3, dn = 1.69).
2) Take the maximum repeatability value, when the flow points q1 and q2 are
subject to separate verification of the liquid-phase flowmeter, and the flow
point q1 is subject to the whole machine verification, as the repeatability of the
gas dispenser.
3) The repeatability of the gas dispenser shall meet the requirements of 5.2.
7.2.6.7 Minimum quality variable
Check the minimum quality variable of the gas dispenser, which shall meet the
requirements of 5.4.
7.2.6.8 Payment amount error
1) The payment amount error can be performed simultaneously with the
maximum allowable error verification.
2) After the single gas filling is completed, record the gas filling volume Qj and
the payment amount Pj displayed on the gas dispenser panel, and use the
Formula (5) to calculate the single payment amount error Ej.
Where:
Ej – the jth gas dispenser payment amount error, yuan;
Pj – the payment amount displayed on the gas dispenser panel after the jth
refilling, yuan;
Qj – the refilling volume displayed on the gas dispenser panel after the jth
refilling, kg;
A.2.2 Check the flow range marked on the nameplate of the gas dispenser, which
shall meet the requirements of 5.3.
A.2.3 The verification flow point and actual flow range shall meet the requirements
in Table 2.
A.2.4 Strictly follow the safety protection requirements in 7.2.6.3 during
verification.
A.2.5 Place the electronic balance on a hard flat ground; ground the electronic
balance, and place an electronic balance windproof device around it; adjust the
electronic balance to a horizontal position; power on and pre-heat the balance to the
prescribed time. According to the weighing range used on site, use standard weights
to calibrate the balance to check whether it is within the maximum allowable error
range.
A.2.6 Before each refilling, use compressed air or nitrogen to purge the surface of
the frost-prone parts such as the dispenser nozzle, filling receptacle, reclaiming
nozzle and reclaiming receptacle.
A.2.7 Place the emptied gas vessel on the electronic balance smoothly; then, reset
the electronic balance to zero (tare).
A.2.8 The circulation process of the gas dispenser: connect the dispenser nozzle of
the gas dispenser and the circulation receptacle (see Figure A.1); turn on the gas
dispenser for filling; observe the transient flow rate displayed on the gas dispenser
panel; at the same time, adjust the flow rate through methods such as adjusting the
output pressure of the cryogenic pump of the fuelling station or reducing the
pressure in the LNG storage tank or installing a control valve at the end of the gas
filling pipeline of the gas dispenser. When it is observed that the flow value of the
circulation process meets the actual flow range corresponding to a certain flow point
and meets the verification conditions such as temperature and density, stop the
circulation process.
Reclaiming
Liquid-phase flowmeter
Control
valve
Fuelling station
LNG storage tank
Dispenser
nozzle
Gas-phase
flowmeter
LNG dispenser
Filling
Regulating valve
Filling
hose
Circulation
receptacle
Eimin – the minimum value of relative error of a single measurement indication value
at the flow point qi, %;
dn – range coefficient (when the number of measurements is 3, dn = 1.69).
A.4.2 Take the maximum repeatability, when the flow points q1 and q2 are subject to
liquid-phase flowmeter separate verification and the flow point q1 is subject to whole
machine verification, as the repeatability of the gas dispenser.
A.4.3 The repeatability of the gas dispenser shall meet the requirements of 5.2.
A.5 Minimum quality variable
Check the minimum quality variable of the gas dispenser, which shall meet the
requirements of 5.4.
A.6 Payment amount error
A.6.1 The payment amount error can be performed simultaneously with the
maximum allowable error verification.
A.6.2 After the single gas filling is completed, record the gas filling volume Qj and
the payment amount Pj displayed on the gas dispenser panel, and use the Formula
(A.4) to calculate the single payment amount error Ej.
Where:
Ej – the jth gas dispenser payment amount error, yuan;
Pj – the payment amount displayed on the gas dispenser panel after the jth refilling,
yuan;
Qj – the refilling volume displayed on the gas dispenser panel after the jth refilling,
kg;
P – the unit price of LNG displayed on the gas dispenser panel, yuan/kg.
A.6.3 Repeat 3 times, the payment amount error shall meet the requirements of 5.5.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.