GB/T 18443.7-2010 PDF English
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Testing method of performance for vacuum insulation cryogenic equipment - Part 7: Holding time measurement
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GB/T 18443.7-2010: PDF in English (GBT 18443.7-2010) GB/T 18443.7-2010
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020
J 74
Testing method of performance for vacuum insulation
cryogenic equipment - Part 7.Holding time measurement
ISSUED ON. SEPTEMBER 26, 2010
IMPLEMENTED ON. FEBRUARY 01, 2011
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3
1 Scope... 4
2 Normative references... 4
3 Terms and definitions... 5
4 Test principles and methods... 5
5 Test devices, equipment and instruments... 5
6 Test conditions and test preparation... 6
7 Test steps... 6
8 Data processing... 7
9 Test record and test report... 8
Annex A (informative) Calculation of holding time of standard state from test results of
static evaporation rate... 9
Annex B (informative) Test record of holding time... 11
Annex C (informative) Test report of holding time... 12
Testing method of performance for vacuum insulation
cryogenic equipment - Part 7.Holding time measurement
1 Scope
This Part of GB/T 18443 specifies test principles and methods, test devices, equipment
and instruments, test conditions and test preparation, test procedures, data processing
and test record and test report for holding time measurement of vacuum insulation
cryogenic equipment.
This Part applies to the holding time measurement of vacuum insulation cryogenic
equipment such as vacuum insulation cryogenic pressure vessels, vacuum insulation
cryogenic welding gas cylinders, except the liquid hydrogen storing and transporting
equipment.
2 Normative references
The provisions in following documents become the provisions of this Part of GB/T
18443 through reference in this Part. For dated references, the subsequent amendments
(excluding corrigendum) or revisions do not apply to this Part, however, parties who
reach an agreement based on this Part are encouraged to study if the latest versions of
these documents are applicable. For undated references, the latest edition of the
referenced document applies.
GB/T 18443.1, Testing method of performance for vacuum insulation cryogenic
equipment - Part 1.Basic requirements
GB/T 18443.2, Testing method of performance for vacuum insulation cryogenic
equipment - Part 2.Vacuum degree measurement
GB/T 18443.3, Testing method of performance for vacuum insulation cryogenic
equipment - Part 3.Leak rate measurement
GB/T 18443.4, Testing method of performance for vacuum insulation cryogenic
equipment - Part 4.Leak-outgassing rate measurement
GB/T 18443.5, Testing method of performance for vacuum insulation cryogenic
equipment - Part 5.Static evaporation rate measurement
GB/T 18443.6, Testing method of performance for vacuum insulation cryogenic
equipment - Part 6.Heat-leak rate measurement
GB/T 18443.8, Testing method of performance for vacuum insulation cryogenic
equipment - Part 8.Volume measurement
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T
18443.1~GB/T 18443.6 as well as the followings apply.
3.1 closed system
A system that during the test, the mass of the medium in the vacuum insulation
cryogenic equipment remains unchanged, with neither medium input nor medium
output.
3.2 tested holding time
The vacuum insulation cryogenic equipment is filled to the initial filling volume
specified in this Part. Start from the starting conditions specified in this Part. Shut down
each pipeline of the equipment. Start timing until the pressure rises to the operating
pressure of the pressure limiting device. The time elapsed for this process is the tested
holding time, in hours (h).
3.3 holding time of standard ambient condition
The tested holding time is converted to the holding time under the standard
environmental state, in hours (h).
4 Test principles and methods
4.1 The holding time of vacuum insulation cryogenic equipment shall be determined by
a closed system.
4.2 When the storage and transportation medium is a non-flammable and explosive
medium, the holding time is allowed to be calculated from the static evaporation rate
of the vacuum insulation cryogenic equipment. Refer to Annex A for the calculation
method.
5 Test devices, equipment and instruments
Test devices, equipment and instruments shall comply with the provisions of 4.2 in
GB/T 18443.1, and shall meet the following requirements.
a) When measuring the holding time of vacuum insulation cryogenic equipment, the
safety valve shall be used as the pressure limiting device of the system. Bursting
discs, back pressure regulators or other pressure limiting devices shall be
temporarily removed or isolated;
b) The opening pressure of the safety valve is the end pressure of the holding time
measurement;
c) The accuracy of the pressure gauge is not less than level 2.5.The diameter of the
dial is not less than 100mm. The range shall be 2 times the maximum test pressure.
Pressure sensors of the same accuracy class and range can also be used.
6 Test conditions and test preparation
6.1 Test conditions and test preparation shall comply with the provisions of GB/T
18443.1.
6.2 The initial conditions for the test of the inner tank pressure of the test piece shall
meet the following requirements.
a) For liquid carbon dioxide and nitrogen oxide medium, take the gauge pressure of
1.5MPa;
b) For other mediums, take the standard atmospheric pressure (101.325kPa), that is,
the gauge pressure of the inner container shall be below 20Pa.
6.3 Except for the vacuum insulation cryogenic equipment specially designed to store
special cryogenic liquids, the test medium of the tested parts shall comply with the
provisions in 4.3 of GB/T 18443.1.
6.4 Determine the initial charge mass at the start of the holding time test.
6.4.1 When the critical pressure of the storage medium of the test piece is higher than
the pressure value set by the test piece pressure limiting device, the filling volume of
the medium at the operating temperature shall not be lower than the design filling
volume of the equipment, and not higher than 98%. Close the overflow valve after
filling.
6.4.2 When the critical pressure of the medium is less than the opening pressure of the
pressure limiting device, the filling amount shall be determined according to the
requirements of the holding time to be measured.
7 Test steps
7.1 The full volume measurement of the inner tank of the test piece can be carried out
according to GB/T 18443.8.Or use the full volume of the inner tank indicated in the
technical documents of the vacuum insulation cryogenic equipment.
Annex A
(informative)
Calculation of holding time of standard state from test results of static
evaporation rate
A.1 Calculate the average loss rate of the test liquid from the static evaporation rate.
The static evaporation rate test is measured according to GB/T 18443.5.
Where,
Qαt - The average loss rate measured by the test liquid, in kilograms per second (kg/s);
V - The effective volume of the inner container, in cubic meters (m3);
α - The static evaporation rate, in percent per year (%/d);
νlt - The specific volume of the test liquid under test pressure, in cubic meters per
kilogram (m3/kg).
A.2 Calculate the heat transfer rate of the shipping liquid
Where,
qs - The calculated heat transfer rate of the shipping liquid, in watts (W);
Qαt - The average loss rate measured by the test liquid, in kilograms per second (kg/s);
hfgt - The latent heat of evaporation of the test liquid under the test pressure, in joules
per kilogram (J/kg);
Tcs - The saturation temperature of the shipping liquid at 1 atmosphere pressure, in
Kelvin (K);
Tct - The saturation temperature of the test liquid at 1 atmosphere pressure, in Kelvin
(K);
νgt - The specific volume of the test liquid vapor under the test pressure, in cubic meters
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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