GB/T 17926-2022 PDF English
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Compressed natural gas cylinder valve for vehicle
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GB 17926-2009 | English | 85 |
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[GB/T 17926-2009] Compressed natural gas cylinder valve for vehicle
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Valves for compression natural gas cylinders for vehicles
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GB/T 17926-2022: PDF in English (GBT 17926-2022) GB/T 17926-2022
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.30
CCS J 74
Replacing GB/T 17926-2009
Compressed natural gas cylinder valve for vehicle
ISSUED ON: MARCH 09, 2022
IMPLEMENTED ON: OCTOBER 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative references ... 6
3 Terms and definitions... 7
4 Basic types ... 7
5 Technical requirements ... 8
5.1 Design requirements ... 8
5.2 Material requirements ... 9
5.3 Process requirements ... 10
5.4 Performance requirements ... 10
6 Inspection and test methods ... 15
6.1 Test conditions ... 15
6.2 Mechanical properties test and chemical composition analysis of metal parts materials .. 16
6.3 Material performance test of non-metallic seals ... 16
6.4 Valve body appearance inspection ... 17
6.5 Inlet and outlet thread inspection ... 17
6.6 Valve performance test ... 17
6.7 Safety pressure relief device performance test ... 22
6.8 Excess flow device performance test ... 25
7 Inspection rules ... 27
7.1 Enter-factory inspection of materials and parts ... 27
7.2 Enter-factory inspection ... 27
7.3 Type test ... 28
8 Marks, packaging and storage ... 32
8.1 Marks ... 32
8.2 Packaging ... 33
8.3 Storage ... 34
Compressed natural gas cylinder valve for vehicle
1 Scope
This Standard specifies the basic types, technical requirements, inspection and test
methods, inspection rules and signs, packaging, storage and transportation of
compressed natural gas cylinder valves for vehicles.
This Standard is applicable to the compressed natural gas cylinder valve for vehicles
(hereinafter referred to as the valve) whose working environment temperature is -
40℃~+85℃ and whose nominal working pressure is not more than 25MPa.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB/T 197, General purpose metric screw threads - Tolerances
GB/T 228.1, Metallic materials - Tensile testing - Part 1: Method of test at room
temperature
GB/T 1173, Casting aluminium alloys
GB/T 3512, Rubber, vulcanized or thermoplastic - Accelerated ageing and heat
resistance tests - Air-oven method
GB/T 3934, Specification of gauges for general purpose screw threads
GB/T 4423, Copper and copper alloy cold-drawn rod and bar
GB/T 5121.1, Methods for chemical analysis of copper – Part 1: The electrolytic
method for the determination of copper content
GB/T 5121.3, Methods for chemical analysis of copper and copper alloys - Part 3:
Determination of lead content
GB/T 5121.9, Methods for chemical analysis of copper and copper alloys - Part 9:
Determination of iron content
GB/T 5231, Designation and chemical composition of wrought copper and copper
alloys
5.2 Material requirements
5.2.1 Metal part material
5.2.1.1 The main metal parts of the valve (valve body, valve stem, valve, pressure cap,
safety cap) shall be made of HPb59-1 bar. Its mechanical properties and chemical
composition shall meet the requirements of GB/T 4423 and GB/T 5231. If other
materials are used, their mechanical properties shall not be lower than those specified
in HPb59-1.
5.2.1.2 The handwheel material shall be ZL 102, which shall meet the requirements of
GB/T 1173.
5.2.1.3 The bursting disc material shall comply with the provisions of GB/T 16918.
5.2.1.4 Fusible alloy materials shall comply with the provisions of GB/T 8337.
5.2.2 Non-metallic seal material
5.2.2.1 Oxygen aging resistance
The non-metallic seals shall be kept for 96h continuously in oxygen with a temperature
of 70℃±5℃, a test pressure of 2MPa and a purity of ≥99.5%, and there shall be no
visible cracks and damages.
5.2.2.2 Ozone aging resistance
Under the elongation of 20%, the rubber seal material shall be placed in the air at a
temperature of 40℃ ± 2℃ and an ozone concentration of (50 ± 5) × 10-8 for 72 hours,
and there shall be no cracks.
5.2.2.3 Dry heat resistance
After the rubber seal material is placed in the air at a temperature of 85℃ for 168 hours,
the change in tensile strength shall not exceed 25%, and the change in elongation shall
range from -30% to +10%.
5.2.2.4 Medium compatibility
5.2.2.4.1 After the non-metallic seals are soaked in natural gas of not less than 0.95
times the nominal working pressure for 70h, there shall be no tearing or cracking. Its
volume expansion rate shall not exceed 25% or shrinkage rate shall not exceed 1%. The
mass loss rate does not exceed 10%.
5.2.2.4.2 Immerse non-metallic seals in n-pentane at a temperature of 23℃±2℃ for 72
hours. The volume change rate shall not exceed 20%. Then place in the air at 40℃ for
48 hours. The mass loss rate shall not exceed 5%.
and 1.2 times the nominal working pressure respectively, and there shall be no air
bubbles.
5.4.1.5 Vibration resistance
At the nominal working pressure, the valve is subjected to vibration tests for 30 minutes
each at the resonance frequency or 500 Hz along the three orthogonal axes. After the
test, there shall be no damage and no loosening of the threaded connection, and shall
meet the requirements of 5.4.1.4.1, 5.4.2.2, 5.4.2.1, 5.4.2.7c) and 5.4.1.6.
5.4.1.6 Pressure resistance
When the valve is kept at 2.5 times the nominal working pressure for 3 minutes, there
shall be no leakage and other abnormal phenomena.
5.4.1.7 Stress corrosion resistance
The valve shall have no cracks after ammonia fumigation in the container box of
ammonia water-air mixture at a temperature of 34℃±2℃ and a time of 240h.
5.4.1.8 Salt spray corrosion resistance
The valve is placed in a salt spray chamber with a temperature of 33℃~36℃. The valve
must be subjected to a 500h salt spray test, which shall comply with 5.4.1.4.1, 5.4.2.1,
5.4.2.2, 5.4.2.7c) and 5.4.1.6.
5.4.1.9 Surface liquid resistance
Immerse the valve in the following three liquids for 24h. There shall be no cracks,
softening or expansion and other damage and phenomena to affect its performance. It
shall meet the requirements of 5.4.1.4.1, 5.4.2.2, 5.4.2.1 and 5.4.1.6.
Liquid used in the test:
a) Sulfuric acid aqueous solution: a solution of sulfuric acid and water with a volume
ratio of 19:81;
b) Ethanol/gasoline: E10 fuel with a volume ratio of 10:90 that meets the
requirements of GB 18351;
c) Windshield washer fluid: a 1:1 volume ratio of methanol and water washer fluid.
5.4.1.10 Durability
The valve shall comply with the provisions of 5.4.1.4.1, 5.4.1.1 and 5.4.1.6 under the
following conditions:
a) When the temperature is 15°C~30°C and it is the nominal working pressure, the
full stroke can be opened and closed 1920 times;
b) When the temperature is 85°C and it is the nominal working pressure, the full
stroke can be opened and closed 40 times;
c) When the temperature is -40°C and it is the nominal working pressure, the full
stroke is opened and closed 40 times.
5.4.2 Safety pressure relief device performance
5.4.2.1 Extrusion resistance
After holding the pressure for 30 minutes at 1.2 times the nominal working pressure,
increase the pressure to 2.25 times the nominal working pressure at a rate of 0.5MPa/s,
and the fusible alloy of PRD shall not be extruded.
5.4.2.2 Air tightness
PRD shall be free of bubbles under the following conditions. If bubbles are found, the
leak rate needs to be measured by an appropriate method. The leakage rate shall be less
than 2cm3/h (under standard conditions):
a) Under the condition of -40°C, the test pressure of PRD shall be maintained for at
least 2min at 0.75 times the nominal working pressure;
b) Under the condition of 85°C, the test pressure of PRD shall be maintained for at
least 2min at 1.3 times the nominal working pressure.
5.4.2.3 Durability
PRD shall meet the requirements of 5.4.2.2 and 5.4.2.7c) under the following conditions:
a) Under the high temperature condition of 85°C, cycle 2000 times within the range
of 10%~100% nominal working pressure;
b) Under the condition of 57℃±2℃, cycle 18000 times within the range of 10%~100%
of the nominal working pressure.
5.4.2.4 Accelerated life
PRD accelerated life shall meet the following requirements:
a) Under the conditions of maximum burst pressure and fusible alloy flow
temperature, PRD operates within 10 hours;
b) Under the conditions of nominal working pressure and accelerated life test
temperature (TL), PRD does not operate within 500h.
Accelerated life test temperature (TL), is expressed as:
Where: Tf is the flow temperature in degrees Celsius (°C).
5.4.2.5 Temperature cycle
PRD temperature cycling shall meet the following requirements:
a) Incubate at -40°C and 85°C for at least 2h each and complete 15 temperature
cycles;
b) Incubate at -40°C for at least 2h. Complete another 100 pressure cycles under the
(10%~100%) nominal working pressure, which meets the requirements of 5.4.2.2
and 5.4.2.7c).
5.4.2.6 Condensation corrosion resistance
Under the temperature condition of 21℃±2℃, soak PRD in the prepared test solution
for 100h and then take it out. When it is heated to 85℃, place for 100h, which shall
meet the requirements of 5.4.2.2 and 5.4.2.7c).
5.4.2.7 Pressure relief
PRD pressure relief shall meet the following requirements:
a) The burst pressure of PRD is the hydraulic test pressure of the matching gas
cylinder, and the allowable deviation is ;
b) The flow temperature of fusible alloy is 110℃±5℃;
c) After PRD is tested for durability, temperature cycling, condensation corrosion
resistance, salt spray corrosion resistance and vibration resistance respectively,
under the condition of 11℃±1℃ above the flow temperature of fusible alloy, the
operating pressure is within the range of 75% to 105% of the PRD reference
operating pressure.
NOTE: The reference operating pressure of PRD is the average value of burst pressure measured
in a).
5.4.2.8 Flowability
Under the pressure state of 0.8MPa~0.9MPa, the difference between the maximum flow
rate and the minimum flow rate of PRD shall be within 10% of the maximum flow rate.
5.4.3 Performance of excess flow device
5.4.3.1 Durability
6.2 Mechanical properties test and chemical composition analysis of metal parts
materials
The test methods for material mechanical properties of main metal parts of the valve
(valve body, valve stem, valve, pressure cap, safety cap) are according to the provisions
of GB/T 228.1. The chemical composition analysis method shall comply with the
provisions of GB/T 5121.1, GB/T 5121.3, GB/T 5121.9 and the provisions of 5.2.1.1.
NOTE: In the case of non-arbitration, the chemical composition analysis methods of metal materials
can choose electrolysis method, atomic absorption method, volume method and spectroscopic
method.
6.3 Material performance test of non-metallic seals
6.3.1 Oxygen aging resistance test
Place 3 non-metallic seal test pieces in the aging test device. Remove air from the device.
Fill with oxygen with a purity of ≥99.5%. Make the pressure reach 2MPa. Warm up to
70℃±5℃. Keep 96h and take out. Visually inspect its changes, which shall meet the
requirements of 5.2.2.1.
6.3.2 Ozone aging resistance test
According to the test method specified in GB/T 13642, put 3 rubber seal material test
pieces at 20% elongation. Put them in an air ozone box with a temperature of 40℃ ±
2℃ and an ozone concentration of (50±5) ×10-8. Keep it for 72h and take it out. Check
its changes with a 25x magnifying glass, which shall meet the requirements of 5.2.2.2.
6.3.3 Dry heat resistance test
According to the test method specified in GB/T 3512, place 3 rubber seal material test
pieces in an air box with a temperature of 85℃ for 168h dry heat resistance test, which
shall meet the requirements of 5.2.2.3.
6.3.4 Medium compatibility test
6.3.4.1 The medium used in this test is compressed natural gas for vehicles. Carry out
at room temperature. Use three samples for each test. Each sample shall be placed on a
small diameter wire loop. Determination of its volume: first weigh in air (M1) and then
in water (M2). Dry the sample. Place it in a test device for compressed natural gas for
vehicles with a working pressure of not less than 0.95 times the nominal working
pressure. After 70h, the samples shall be taken out of the device one by one without
cracks and weighed in the air on the same wire ring (M3). This mass shall be weighed
within 3 minutes after it leaves the test medium. Determine the final mass in water
immediately afterwards (M4). Each sample shall be immersed in ethanol and then in
6.6.1.1 Opening-closing test at room temperature
Install the valve on the test special device. Keep the valve closed. Charge the air source
from the valve air inlet to the nominal working pressure. Block the air outlet. Open the
valve according to the torque specified in Table 1. The valve shall be able to open fully.
Then close the valve according to the torque specified in Table 1. The valve shall be
able to close and comply with the provisions of 5.4.1.1.
6.6.1.2 Opening-closing test at low temperature
Install the valve on the test special device. Place in a temperature-controlled box at -
40°C. Keep the valve closed. Charge the air source from the valve air inlet to the
nominal working pressure. Block the air outlet. Open the valve according to the torque
specified in Table 1. The valve shall be able to open fully. Then close the valve
according to the torque specified in Table 1. The valve shall be able to close and comply
with the provisions of 5.4.1.1.
6.6.2 Excess torque resistance test
Use a nut or plug to screw the air outlet of the valve. Then tighten the nut or plug with
150% of the installation torque, respectively. The applied torque shall be maintained for
more than 15min. Then remove the nut or plug. Visually inspect the valve that shall not
be deformed or damaged. Carry out the test according to the provisions of 6.6.4.1 and
6.6.6, which shall comply with the provisions of 5.4.1.4.1 and 5.4.1.6.
Install the air inlet of the valve on the test special device. Use a torque wrench to tighten
according to the installation torque specified in Table 2. Carry out the test according to
the provisions of 6.6.4.1 and 6.6.6, which shall comply with the provisions of 5.4.1.4.1
and 5.4.1.6.
6.6.3 Bending moment test
Fix the air inlet of the valve to the test rig (see Figure 1). Connect a pipe longer than
300mm to the outlet of the valve. Fill the pipeline with 0.05MPa air and follow the steps
below:
a) Apply the force specified in Table 3 in any direction of the vertical (up and down)
and horizontal (left and right) directions of the force point. Keep it for at least
15min. Use leak detection fluid to coat valve outlet threaded connections without
removing force. Visually inspect it and there shall be no leakage;
b) Follow step a) to complete the other three direction tests;
c) After completing the above test steps, remove the valve. Visually inspect the valve
and there shall be no deformation. Carry out the test according to the provisions
of 6.6.4.1 and 6.6.6, which shall comply with the provisions of 5.4.1.4.1 and
5.4.1.6.
pressure. Immerse the valve in water to maintain pressure for at least 2min, which shall
meet the requirements of 5.4.1.4.1b).
6.6.4.1.3 High temperature test
Install the valve on the test special device. Keep the valve in any open state. Block the
air outlet and place in water. Put it in the thermostat. Through the external pipeline, fill
the air source into the valve to 0.05 times and 1.5 times the nominal working pressure,
respectively. Keep this pressure. Then gradually increase the temperature to 85°C ± 2°C
while the initial temperature is room temperature. When the specimen valve reaches
this temperature, visually inspect the valve for at least 2 minutes, which shall meet the
requirements of 5.4.1.4.1c).
Install the valve on the test special device. Close the valve and place in water. Put it in
the thermostat. Through the external pipeline, fill the air source into the valve to 0.05
times and 1.5 times the nominal working pressure, respectively. Keep this pressure.
Then gradually increase the temperature to 85°C ± 2°C while the initial temperature is
room temperature. When the specimen valve reaches this temperature, visually inspect
the valve for at least 2 minutes, which shall meet the requirements of 5.4.1.4.1c).
6.6.4.2 Exit-factory inspection air tightness
At room temperature, according to the test method specified in 6.6.4.1.2, fill the valve
with 0.025 times and 1.2 times the nominal working pressure respectively for air
tightness test. Keep it for 1min, which shall comply with 5.4.1.4.2.
6.6.5 Vibration resistance test
Install the valve on the test special device. Block the air outlet. Open the valve. Fill the
valve with air source to the nominal working pressure. Mount the device on a vibration
test bench. In the sinusoidal range of 10Hz to 500Hz, conduct sweep vibration at an
acceleration of 1.5g for 10min. Find the resonant frequency of the valve. At this
frequency, the valve is subjected to vibration tests for 30 minutes along the three
orthogonal axes, respectively. If no resonance frequency is found, the valve shall be
subjected to vibration tests for 30 minutes respectively along the three orthogonal axes
at a frequency of 500Hz. After the test, there shall be no damage and no loosening of
the threaded connections. Then carry out the test according to the provisions of 6.6.4.1,
6.7.2, 6.7.1, 6.7.7.3 and 6.6.6, which shall comply with 5.4.1.4.1, 5.4.2.2, 5.4.2.1,
5.4.2.7c) and 5.4.1.6.
6.6.6 Pressure resistance test
Remove safety relief from valve. Block each vent between the valve and the outside
world (except the air inlet connected to the gas cylinder). Open the valve. Connect the
air inlet of the valve to the water pressure pump. Fill the valve with clean water. Boost
to 2.5 times the nominal working pressure. Keep this pressure for 3min, which shall
comply with the provisions of 5.4.1.6.
6.6.7 Stress corrosion resistance test
Pour ammonia water with a relative density of 0.94 (specific gravity) into a glass
container with a lid. The ratio of the added ammonia water to the container volume is
21.2 ml/L (for example, 636mL of ammonia water is added to a 30L glass container).
Use a torque specified by the manufacturer to screw the air inlet and outlet of the valve
on the plug. No fillers such as Teflon are allowed to be attached to the thread. The valve
is then placed in a lidded glass container with ammonia water. The valve shall be placed
40mm above the ammonia water level. Cover with glass cover. Put the glass container
in a temperature-controlled box. The set temperature is 34℃±2℃. After 240h of heat
preservation, the valve shall be inspected under a magnifying glass of 25 times, which
shall meet the requirements of 5.4.1.7.
6.6.8 Salt spray corrosion resistance test
Place the valve in a salt spray chamber between 33°C and 36°C. Block the air inlet and
outlet. Without any cover, use a salt solution composed of 5% sodium chloride and 95%
distilled water (by weight), to continuously carry out the salt spray test to the valve for
500h. Then take out. Immediately rinse the test piece with clean water. Gently wipe
away salt deposits. Carry out the test according to the provisions of 6.6.4.1, 6.7.2, 6.7.1,
6.7.7.3 and 6.6.6, which shall comply with 5.4.1.4.1, 5.4.2.2, 5.4.2.1, 5.4.2.7c) and
5.4.1.6.
6.6.9 Surface liquid resistance test
Block the valve inlet and outlet. Carry out the test as follows:
a) Soak the valve in a solution of sulfuric acid and water in a volume ratio of 19:81.
After soaking for 24 hours, rinse and wipe the valve with clean water. It shall
meet the requirements of 5.4.1.9, that is, there is no cracks, softening or expansion
and other damages that affect its performance;
b) Immerse the valve in a mixed solution of E10 fuel ethanol and gasoline with a
concentration of 10:90 by volume. After soaking for 24 hours, rinse the wipe
valve with clean water. It shall meet the requirements of 5.4.1.9, that is, there is
no cracks, softening or expansion and other damages that affect its performance;
c) Soak the valve in a 1:1 volume ratio of methanol and water in a windshield washer
solution. After soaking for 24 hours, rinse the wipe valve with clean water. It shall
meet the requirements of 5.4.1.9, that is, there is no cracks, softening or expansion
and other damages that affect its performance;
d) After immersion in three liquids, the test shall be carried out according to the
provisions of 6.6.4.1, 6.7.2, 6.7.1 and 6.6.6, which shall meet the provisions of
5.4.1.4.1, 5.4.2.2, 5.4.2.1 and 5.4.1.6.
6.6.10 Durability test
times/min. Complete 18000 cycles at 57°C ± 2°C. The fusible alloy shall be free of
extrusion after the specified number of cycles.
After completing the above test, carry out the test according to the provisions of 6.7.2
and 6.7.7.3, which shall meet the provisions of 5.4.2.2 and 5.4.2.7c).
6.7.4 Accelerated life test
Install the valve with PRD on the test special device. Keep the valve closed. Place in a
high and low temperature box or a liquid bath. Gradually increase the temperature, so
that the temperature of the PRD is controlled within the range of ±1°C of the flow
temperature. Charge the air source to the air inlet of the valve through the external
pipeline to the maximum burst pressure. It shall act within 10h under this pressure and
temperature and meet the requirements of 5.4.2.4a).
Install the valve with PRD on the test special device. Keep the valve closed. Place in a
high and low temperature box or a liquid bath. Gradually increase the temperature, so
that the temperature of PRD is controlled at the accelerated life test temperature TL. Fill
the air source from the valve air inlet through the external pipeline to the nominal
working pressure (tolerance is ±0.7MPa). Keep at this pressure and temperature for
more than 500h, which shall comply with the provisions of 5.4.2.4b).
6.7.5 Temperature cycle test
PRD is tested according to the following steps:
a) Put the valve with PRD in the liquid tank or high and low temperature box at -40℃
for at least 2h. Take out the valve. Within 5min, place it in a liquid tank or a high
and low temperature box with a temperature of 85°C for at least 2h;
b) Take out the valve that has been placed in the liquid tank or high and low
temperature box at a temperature of 85°C for at least 2h. Within 5min, place the
valve in a liquid tank or a high and low temperature box with a temperature of -
40°C for at least 2h;
c) Above-mentioned a), b) step is a temperature cycle. Repeat steps a) and b).
Complete 15 temperature cycles;
d) Put the valve that has completed the temperature cycle in a liquid tank or a high
and low temperature box with a temperature of -40°C for at least 2h. Charge the
air source to the air inlet of the valve through the external pipeline to the nominal
working pressure. Then reduce from nominal working pressure to below 10%
nominal working pressure. This boost-to-buck process is a pressure cycle. PRD
completes 100 pressure cycles at a cycle frequency of no more than 10 cycles/min.
After the above tests are completed, the test shall be carried out according to the
provisions of 6.7.2 and 6.7.7.3, which shall comply with the provisions of 5.4.2.2 and
...... Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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