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

Foreword

GB/T 18443 "Testing method of performance for vacuum insulation cryogenic equipment" consists of the following 8 parts.

- Part 1: Basic requirements;

- Part 2: Vacuum degree measurement;

- Part 3: Leak rate measurement;

- Part 4: Leak-outgassing rate measurement;

- Part 5: Static evaporation rate measurement;

- Part 6: Heat-leak rate measurement;

- Part 7: Holding time measurement;

- Part 8: Volume measurement. This is Part 7 of GB/T 18443.

Annex A, Annex B and Annex C of this Part are informative.

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

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.

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.

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. […]

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.

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.

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.O

7.2 The initial filling amount shall comply with the provisions of 6.4.

7.3 The system to be tested shall be left empty for not less than 48h. After the inner pressure of the inner tank of the test piece reaches the pressure specified in 6.2, open the overflow valve. Drain excess fluid.

7.4 When the pressure of the inner tank rises to the opening pressure of the safety valve and the safety valve starts to move, stop the timing.

7.5 Start timing from closing all valves until the safety valve starts to operate. The time elapsed in the whole process is recorded in hours and minutes as "tested holding time".

8 Data processing

8.1 High vacuum multilayer insulation holding time H20 of standard state (standard ambient condition)

8.3 High vacuum insulation holding time H20 of standard state

9 Test record and test report

9.1 Refer to Annex A for the test record format.

Annex A (informative) Calculation of holding time of standard state from test results of static evaporation rate

Annex B (informative)

Test record of holding time Refer to Table B.1 for the test record of holding time.

Annex C (informative)

Test report of holding time Refer to Table C.1 for test report of holding time. […]