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GB/T 18443.7-2010 English PDF (GBT18443.7-2010)

GB/T 18443.7-2010 English PDF (GBT18443.7-2010)

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GB/T 18443.7-2010: Testing method of performance for vacuum insulation cryogenic equipment -- Part 7: Holding time measurement

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.
GB/T 18443.7-2010
NATIONAL STANDARD OF THE
PEOPLE 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,
Q??t - 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);
?? - The static evaporation rate, in percent per year (%/d);
??lt - 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); Q??t - 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);
??gt - The specific volume of the test liquid vapor under the test pressure, in cubic meters

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