GB/T 31480-2015 PDF in English
GB/T 31480-2015 (GB/T31480-2015, GBT 31480-2015, GBT31480-2015)
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Materials for high vacuum multilayer insulation of cryogenic vessel
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GB/T 31480-2015: PDF in English (GBT 31480-2015) GB/T 31480-2015
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.40
A 82
Materials for high vacuum multilayer insulation of
cryogenic vessel
ISSUED ON: MAY 15, 2015
IMPLEMENTED ON: SEPTEMBER 01, 2015
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions... 5
4 Product types and models ... 6
5 Raw materials ... 9
6 Technical requirements ... 12
7 Test methods ... 14
8 Inspection rules ... 15
9 Sign, product exit-factory information ... 16
10 Packaging, transport, storage ... 17
Appendix A (Normative) Test method for apparent thermal conductivity ... 18
Appendix B (Normative) Test method of outgassing rate ... 26
Materials for high vacuum multilayer insulation of
cryogenic vessel
1 Scope
This standard specifies the product types and models, raw materials, technical
requirements, test methods, inspection rules, markings, product exit-factory
information, packaging, transportation, storage requirements of materials for high
vacuum multilayer insulation of cryogenic vessel.
This standard is applicable to the thermal insulation material, which is alternately
combined with spacing materials and heat-resistant radiation shields for high vacuum
multilayer insulation of cryogenic vessel.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 451.1 Paper and board - Determination of size and deviation
GB/T 451.2 Paper and board - Determination of size and deviation
GB/T 451.3 Paper and board - Determination of grammage
GB/T 3198 Aluminium and aluminium-alloy foil
GB/T 9914.2 Test method for reinforcement products - Part 2: Determination of
combustible - Matter content for glass fiber
GB/T 12914 Paper and board - Determination of tensile properties
GB/T 14014 Synthetic fiber bolting cloths
GB/T 15717 Test method for vacuum-deposited metal thickness - Electric resistance
method
GB/T 16958 Biaxially oriented polyester film for package
qualification certificate shall be provided.
5.1.2 According to the operating conditions of the cryogenic vessel, the compatibility
with oxygen shall be considered, when selecting raw materials.
5.1.3 The technological properties of raw materials shall be able to meet the
requirements of construction, baking temperature resistance, vacuuming of cryogenic
vessels.
5.1.4 When there are special requirements, the supplier and the buyer can negotiate
separately.
5.2 Spacing material
5.2.1 Types of spacing materials and their compatibility with oxygen
5.2.1.1 Typical types of spacing materials include glass fiber paper, glass fiber cloth,
chemical fiber paper, synthetic fiber screen, etc.
5.2.1.2 The compatibility of the spacing material with oxygen shall be evaluated,
according to 4.3 of GB/T 31481-2015.
5.2.2 Glass fiber paper
5.2.2.1 The thickness shall be tested according to the method of GB/T 451.3, which
should not be greater than 0.08 mm.
5.2.2.2 Quantitatively test shall be according to the method of GB/T 451.2, which
should be (14 ± 2.0) g/m2.
5.2.2.3 The longitudinal tensile strength shall be tested, according to the method of
GB/T 12914, which should not be less than 0.03 kN/m.
5.2.2.4 The content of combustibles shall be tested, according to the method of GB/T
9914.2, which should not exceed 1.0% (mass fraction).
5.2.3 Glass fiber cloth
5.2.3.1 The glass fiber cloth shall meet the requirements of JC/T 170.
5.2.3.2 The thickness shall be tested, according to the method of GB/T 451.3, which
should be 0.05 mm ~ 0.25 mm.
5.2.3.3 The longitudinal tensile strength shall be tested, according to the method of
GB/T 12914, which should not be less than 0.06 kN/m.
5.2.3.4 It needs to be degreased and dewaxed; the content of combustibles shall be
tested, according to the method of GB/T 9914.2, which shall not exceed 0.2% (mass
2004. The surface shall have a continuous, bright luster, without oil traces; the edges
shall be smooth and flat. Looking at the light source, there shall be no obvious scratches,
holes, impurities, or aluminized layer falling off.
5.3.3.2 The base material of aluminized polyester film shall comply with the provisions
of GB/T 16958; the thickness should be 0.005 mm ~ 0.025 mm.
5.3.3.3 The thickness of the aluminized layer shall be tested, according to the method
of GB/T 15717, which should not be greater than 1.0 Ω/□ (resistance method).
5.3.3.4 The uniformity of the aluminized layer shall be tested, according to the method
of GB/T 15717, which should be better than ±10%.
5.3.3.5 The adhesion of the aluminized layer (represented by the peeling area of the
aluminized layer) shall be tested, according to the method in 6.12 of BB/T 0030-2004,
which shall not exceed 10%.
6 Technical requirements
6.1 Manufacturing environment requirements
6.1.1 The whole manufacturing process shall be carried out in a clean environment.
6.1.2 The surface of the production equipment, tooling, tools, which are in contact with
the material, shall be kept clean and free of oil.
6.1.3 The human body shall avoid direct contact with raw materials, during the
production process.
6.2 Manufacturing requirements for multilayer insulation units
6.2.1 The heat-resistant radiation shield can be provided with ventilation holes.
6.2.2 The spacing material and the heat-resistant radiation shield layer shall not be fixed
by chemical adhesives, such as adhesives and tapes.
6.2.3 The surface of the multilayer insulation unit shall be clean; there shall be no oil
stains, sweat stains, fingerprints, or other stains.
6.2.4 The spacing material shall be parallel to the edge of the heat-resistant radiation
shield; the width of the spacing material shall be greater than the width of the heat-
resistant radiation shield. The heat-resistant radiation shield shall be evenly distributed
in the middle of the spacing material; the indentation on both sides of the heat-resistant
radiation shield shall be not less than 2 mm and not more than 18 mm.
6.2.5 The width of the multilayer insulation unit shall be subject to the width of the
spacing material; the allowable deviation of its width shall comply with the provisions
6.3.2.3 The length of the core of the multilayer insulation roll shall not be less than the
width of the product; either end shall not be recessed into the product.
6.3.3 Manufacturing requirements for multilayer insulation blankets
6.3.3.1 Fixing measures shall be taken between the multilayer insulation units; the
fixings shall be clean and evenly distributed.
6.3.3.2 Chemical adhesives, such as adhesives and tapes, shall not be used for fixing.
6.3.3.3 There shall be no obvious deviation in the thickness of the same multilayer
insulation blankets.
7 Test methods
7.1 Appearance quality
The appearance quality shall be visually inspected as required. The surface cleanliness
shall meet the requirements of 6.3.1.1.
7.2 Indentation of the heat-resistant radiation shield
The indentation of the heat-resistant radiation shield shall be tested, according to the
method of GB/T 451.1, which is expressed as the distance between the edge of the heat-
resistant radiation shield and the edge of the spacing material. It shall comply with the
provisions of 6.2.4.
7.3 Width deviation
The width deviation shall be tested, according to the method of GB/T 451.1, which shall
comply with the provisions of 6.2.5.
7.4 Width misalignment
The width misalignment shall be tested, according to the method of GB/T 451.1,
expressed as the misalignment of the same side edge of the spacing material of 2
multilayer insulation units, which shall comply with the provisions of 6.3.1.2.
7.5 Apparent thermal conductivity
The apparent thermal conductivity shall be tested, according to the method specified in
Appendix A, which shall meet the requirements of 6.2.6.
7.6 Outgassing rate
The outgassing rate shall be tested, according to the method specified in Appendix B,
which shall meet the requirements of 6.2.7.
7.7 Temperature resistance
Take a representative sample of 300 mm x 300 mm multilayer insulation unit. Sandwich
it between two 300 mm x 300 mm galvanized sheets, which have a thickness of 2 mm.
Place it in an oven. Heat it to (170 ± 5) °C. Keep it for 24 h. Take out the sample for
visual inspection. It shall meet the requirements of 6.2.8.
7.8 Compatibility test
7.8.1 The platinum wire combustion test of representative specimen and oxygen shall
be tested, according to the relevant methods in GB/T 31481-2015.
7.8.2 The representative specimen of the multilayer insulation roll is the full-thickness
specimen of the high-vacuum multilayer thermal insulation material, which is wound
in the interlayer space of the cryogenic vessel.
7.8.3 The representative specimen of the multilayer insulation blanket is the full-
thickness specimen of the high-vacuum multilayer thermal insulation blanket.
8 Inspection rules
8.1 Inspection classification
The inspection is divided into multilayer insulation unit inspection, product inspection,
performance test. The inspection items are as shown in Table 3.
8.2 Inspection of multilayer insulation unit
The inspection of multilayer insulation unit is a piece-by-piece inspection; the items are
as specified in Table 3.
8.3 Product inspection
The product inspection is a piece-by-piece inspection; the items are as specified in Table
3.
8.4 Performance test
If it is one of the following situations, the performance test shall be carried out. The test
items shall be in accordance with the provisions of Table 3:
a) When the product design is finalized;
b) After formal production, if there are changes in raw materials, processes, etc.,
which may affect product performance;
c) For normally produced products, a performance test shall be carried out once a
A.3 Test devices and instruments
A.3.1 Composition of the test device
The apparent thermal conductivity test device is mainly composed of a calorimeter, a
vacuum system, a flow measurement system, a temperature measurement and control
system.
- The calorimeter includes: The liquid inlet & outlet of protection section, the liquid
inlet & outlet of measuring section, the inner cylinder of the calorimeter, the outer
cylinder of the calorimeter, the upper protection section, the measurement section,
the lower protection section, the measured thermal insulation material;
- The vacuum system includes: The vacuum unit, vacuum valve, vacuum meter,
vacuum gauge;
- The flow measurement system includes: The heater, pressure gauge, thermometer,
gas mass flow meter;
- The temperature measurement and control system includes: The cold boundary
temperature measurement point, hot boundary thermometer measurement point,
temperature control device.
A.3.2 Requirements for test devices and instruments
A.3.2.1 Calorimeter:
a) The outer diameter of the test section is (130 ± 2) mm and the length is (380 ± 2)
mm; the diameter of the protection section is the same as that of the measurement
section, the length of the upper protection section is not less than 400 mm; the
length of the lower protection section is not less than 100 mm;
b) The inner diameter of the outer cylinder is (220 ± 5) mm;
c) The temperature range of the cold boundary of the measuring section is (77 ± 2)
K; the temperature range of the hot boundary is (293 ± 5) K.
A.3.2.2 Vacuum system:
a) The ultimate vacuum of the vacuum unit shall be more than an order of magnitude
higher than the vacuum degree, which is required by the test;
b) The effective pumping speed of the vacuum unit shall meet the gas load
requirements of the vacuum interlayer of the calorimeter, during the test of the
maximum design specimen;
c) Rubber-sealed vacuum gauge pipe joints shall comply with the requirements of
JB/T 8105.1; metal-sealed vacuum gauge pipe joints shall comply with the
requirements of JB/T 8105.2;
d) The type and measurement range of the vacuum gauge and the supporting vacuum
gauge shall meet the requirements of the interlayer vacuum; the uncertainty of
vacuum measurement shall be less than 20%.
A.3.2.3 Flow measurement system:
a) The allowable measurement error of the barometer and the pressure gauge, for
measuring the pressure at the outlet of the gas mass flowmeter, is ±50 Pa;
b) The allowable measurement error of the thermometer, for measuring the gas
temperature at the outlet of the gas mass flowmeter, is ±1 K;
c) When the range of the gas mass flowmeter is less than or equal to 5 L/min, the
accuracy shall reach 0.5%; when the range is greater than 5 L/min, the accuracy
shall reach 1.0%;
d) The rated flow rate of the gas mass flowmeter shall be 1 ~ 2 times the gas flow
rate, which is evaporated in the measurement section.
A.3.2.4 Temperature measurement and control system:
a) A platinum resistance thermometer or a thermocouple thermometer can be used,
to measure the temperature of the hot and cold boundary; the allowable
measurement error of the thermometer is ±0.5 K;
b) The outer cylinder's temperature control device controls the thermal boundary
temperature range to be (293 ± 5) K.
A.3.2.5 The material of the connecting pipeline should be stainless steel, copper or
aluminum alloy.
A.3.2.6 Measuring tools and instruments shall be calibrated, by the national legal
metrology agency AND within the validity period.
A.3.3 Test conditions and specimen preparation
A.3.3.1 Test conditions:
a) The test environment shall be clean, which has anti-static, anti-open flame and
other measures;
b) There shall be no strong electromagnetic interference, strong vibration or shock,
at the test site;
c) The zero and ground of the test power are separated; the chassis of the test system
is grounded; all electrical instruments and meters shall be well grounded at a
e) Put the inner cylinder of the calorimeter, with the wrapped specimen, into the
outer cylinder of the calorimeter, to ensure a good seal.
A.4.2 Vacuuming:
a) Start the vacuuming system, to vacuumize the interlayer of the calorimeter;
b) When the vacuum degree of the interlayer of the calorimeter is better than 1 × 10-
1 Pa, slowly add liquid nitrogen into the upper and lower protection sections and
the measuring section of the calorimeter, until the liquid nitrogen overflows at
both outlets of the inner cylinder, to ensure that within the test period, the vacuum
degree of the interlayer is better than 1 × 10-2 Pa (cold state).
A.4.3 Measurement and recording:
a) Use a barometer, to measure and record the ambient atmospheric pressure p;
b) After the first inner cylinder is filled with liquid nitrogen and left to stand for 1
hour, fill liquid nitrogen to the upper and lower protection sections and the test
section again, until the liquid nitrogen overflows from both liquid outlets of the
inner cylinder;
c) After no liquid nitrogen flows out from the outlet of the test section of the
calorimeter, connect it to the heater and the gas mass flowmeter;
d) Connect the liquid inlet & outlet of upper protection section to the bubbler;
e) Record the temperature T1 and pressure p1, at the outlet of the gas mass flowmeter,
every 10 min;
f) Record the flow rate of the gas mass flowmeter every 10 min. When the flow rate
change, at any two time intervals, within one hour, is less than 5%, the system is
deemed to be stable. Start measuring and recording the flow rate for the next 1 h.
Use this to calculate the average flow qm;
g) When the system reaches a steady state, record the cold and hot boundary
temperatures Tc and Th of the specimen, once every 10 minutes. Record
continuously for 1 hour;
h) After the measurement, close the vacuum valve. Close the vacuum unit;
i) Disconnect the liquid outlet of the measuring section from the heater and
flowmeter;
j) The heat pipe can be inserted into the middle and lower sections of the calorimeter,
to discharge the remaining low-temperature liquid, so that the calorimeter can
naturally return to normal temperature, OR wait for the calorimeter to naturally
return to normal temperature.
b) The test chamber shall be made of materials, which have a low outgassing rate.
B.3.2 Leak detector:
The minimum detectable leak rate shall be less than 1 × 10-11 Pa·m3/s.
B.3.3 Vacuum system:
a) The ultimate vacuum of the vacuum unit shall be better than 1 × 10-5 Pa;
b) The effective pumping speed of the vacuum unit shall meet the gas load
requirements of the specimen.
B.3.4 Vacuum measurement system:
a) Metal-sealed vacuum gauge pipe joints shall comply with the requirements of
JB/T 8105.2;
b) The type and measurement range of the vacuum gauge and the associated vacuum
gauge shall meet the requirements of the specified vacuum degree of the test
chamber; the measurement uncertainty of the vacuum degree shall be less than
10%.
B.3.5 The material of the connecting pipeline should be stainless steel, copper or
aluminum alloy.
B.3.6 Measuring tools and instruments shall be calibrated, by the national legal
metrology agency AND within the validity period.
B.4 Test conditions and test preparation
B.4.1 Test conditions:
a) The test environment shall be clean; there shall be anti-static, anti-open flame and
other measures;
b) There shall be no strong electromagnetic interference, strong vibration or shock,
at the test site;
c) The ambient pressure is the local atmospheric pressure; the temperature range is
0 °C ~ 40 °C; the relative humidity is less than 85%.
B.4.2 Test preparation:
a) Use a balance, to weigh (20 ± 2) g of specimen from the sample, accurate to 0.001
g. Record the balance reading m;
b) Use a helium mass spectrometer leak detector, to carry out leak detection of the
V - The volume of the test chamber, in cubic meters (m3);
p1 - When the valve is closed, the vacuum gauge's reading, in Pascal (Pa);
p2 - After the 60 min time interval, the vacuum gauge's reading, in Pascal (Pa);
Δt - Test time interval, in seconds (s).
B.5.2.2 When the calculated result of the background leakage and outgassing rate of
the test chamber is less than 2 × 10-8 Pa·m3/s, proceed to the next test. Otherwise, after
reprocessing the test device, proceed again according to B.4.
B.5.3 Background (including specimen) leakage and outgassing rate test of test
chamber
The test steps are as follows:
a) Put the weighed specimen into the test chamber and seal it;
b) Start the vacuum unit, to pre-pump the test chamber. After the pressure of the test
chamber is lower than the maximum pressure of the leak detection port, which is
allowed by the leak detector, open the helium mass spectrometer, to check the
system for leaks. Read and record the indicated value of the leak detector. It is
required that the system leakage rate is less than 1 × 10-9 Pa·m3/s; otherwise, the
system shall be re-sealed and leak-checked, until this requirement is met;
c) Turn on the vacuum unit, to pump air from the test chamber for 2 hours. Then
close the vacuum valve of the test chamber. Let it stand for 1 hour. Open the
vacuum valve of the test chamber. Pump the air from the test chamber for 1 hour;
d) Close the vacuum valve of the test chamber. Let it stand for 1 h;
e) Open the vacuum valve of the test chamber. Pump air from the test chamber for 1
h;
f) Close the vacuum valve of the test chamber. Record the vacuum gauge's reading
p3. Record the vacuum gauge's reading p4, after 60 min.
B.6 Data processing
B.6.1 The background (including the specimen) leakage and outgassing rate of the test
chamber is calculated, according to formula (B.2):
Where:
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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