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GB/T 18442 consists of the following seven parts under the general title Static vacuum insulated cryogenic pressure vessels:
——Part 1: General requirements;
——Part 2: Materials;
——Part 3: Design;
——Part 4: Fabrication;
——Part 5: Inspection and testing;
——Part 6: Safety protection;
——Part 7: Rules of pressure strengthening for inner vessels.
This is part 5 of GB/T 18442.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 18442.5-2011 Static vacuum insulated cryogenic pressure vessel - Part 5: Inspection and test. In addition to editorial changes, the following main technical changes have been made with respect to GB/T 18442.5-2011:
—— the test sequence is modified, and the implementation time is added for cold shock test, pressure test, leakage test, vacuum performance test, etc.;
—— the test requirements are modified for the pressure test, and the safety measures and basic requirements are added for the hydraulic test;
—— the requirements are modified for cold shock test;
—— the inspection requirements are added for cleanliness;
—— the selection rules are added for the test tank of the low temperature performance type test;
—— the contents and requirements are modified for other inspection items.
This part was proposed by and is under the jurisdiction of the National Technical Committee 262 on Boilers and Pressure Vessels of Standardization Administration of China.
The previous editions replaced by this part are as follows:
—— GB/T 18442.5-2011;
—— GB 18442-2001.
Static vacuum insulated cryogenic pressure vessels - Part 5: Inspection and testing
1 Scope
This part of GB/T 18442 specifies the test methods and inspection rules for static vacuum insulated cryogenic pressure vessels (hereinafter referred to as "cryogenic vessels") during the fabricating process and after completion.
This part is applicable to cryogenic vessels that simultaneously meet the following conditions:
a) cryogenic vessel with the working pressure of inner vessel is not less than 0.1 MPa;
b) cryogenic vessel with the geometric volume is not less than 1 m3;
c) cryogenic vessel with the insulation mode of vacuum powder insulation, vacuum composite insulation or high vacuum multilayer insulation;
d) cryogenic vessel storing refrigerated liquefied gas content with standard boiling point not lower than -196 ℃;
This standard is not applicable to the following cryogenic vessels:
a) cryogenic vessel with inner vessel and outer jacket made of non-ferrous metal or non-metal materials
b) cryogenic vessel with spherical structure;
c) cryogenic vessel with stacked insulation;
d) transportable cryogenic vessel;
e) cryogenic vessel storing refrigerated liquefied gas content with standard boiling point lower than -196 ℃;
d) cryogenic vessel storing toxic gas as specified in GB 12268;
g) cryogenic vessel with special requirements such as national defense military equipment.
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 150 (All parts) Pressure vessels
GB/T 18442.1 Static vacuum insulated cryogenic pressure vessels - Part 1: General requirements
GB/T 18442.2-2019 Static vacuum insulated cryogenic pressure vessels - Part 2: Materials
GB/T 18442.3-2019 Static vacuum insulated cryogenic pressure vessels - Part 3: Design
GB/T 18442.4-2019 Static vacuum insulated cryogenic pressure vessels - Part 4: Fabrication
GB/T 18442.6-2019 Static vacuum insulated cryogenic pressure vessels - Part 6: Safety protection
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: Vacuum degree measurement
GB/T 18443.5 Testing method of performance for vacuum insulation cryogenic equipment - Part 5: Static evaporation rate measurement
GB/T 18443.7 Testing method of performance for vacuum insulation cryogenic equipment - Part 7: Holding time measurement
GB/T 18443.8 Testing method of performance for vacuum insulation cryogenic equipment - Part 8: Volume measurement
GB/T 20801.5 Pressure piping code - Industrial piping - Part 5: Inspection and testing
JB/T 6896 Surface cleanliness of air separation plants
TSG 21 Supervision regulation on safety technology for stationary pressure vessel
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 150, GB/T 18442.1, GB/T 18442.3 and GB/T 18442.4, as well as the following apply.
3.1
cold shock test
fill the inner vessel with refrigerated liquefied gas at a set speed to cool the inner vessel to a predetermined temperature within a specified time, so as to investigate the ability of the inner vessel to withstand the speed and amplitude of temperature difference stress change
4 Test methods
4.1 Test sequence
4.1.1 If a cold shock test is required, it shall be carried out after the inner vessel is fabricated and passes the non-destructive test.
4.1.2 The pressure test of the inner vessel shall be carried out after the inner vessel is fabricated and passes the non-destructive test.
4.1.3 Helium mass spectrometry leak detection test for tank annular space shall be carried out after the inner vessel and outer jacket are assembled.
4.1.4 The pressure test of the external pipeline shall be carried out after the tank and external pipeline are fabricated and pass the non-destructive test.
4.1.5 Leakage test shall be carried out after the tank and pipeline system are assembled and all safety accessories, instruments and loading and unloading accessories are fully installed.
4.1.6 The cryogenic vessel may be subjected to low temperature performance inspection only after passing the pressure test and leakage test and the annular space vacuum pumping is completed. The static evaporation rate inspection shall be carried out after the vacuum performance inspection is acceptable, and the maintenance time inspection (if necessary) shall be carried out after the static evaporation rate inspection is completed.
4.2 Pressure test
4.2.1 Inner vessel pressure test
4.2.1.1 Basic requirements of pressure test
4.2.1.1.1 The finished inner vessels shall be subjected to pressure test (hydraulic pressure test, gas pressure test) according to those specified in the drawing.
4.2.1.1.2 Two verified pressure gauges with the same measuring range shall be used for the pressure test. The measuring range of the pressure gauge shall be 1.5 to 3.0 times the test pressure, and 2 times the test pressure is appropriate. The accuracy of the pressure gauge shall not be inferior to Grade 1.6, and the dial diameter shall not be less than 100 mm. The pressure gauge shall be installed on the pipeline leading from the top of the test inner vessel for easy observation.
4.2.1.1.3 Before the pressure test, the fastening bolts (if any) at each connection part of the inner vessel shall be fully configured and properly fastened, and the inner vessel and annular space pipeline shall be subjected to pressure test together as much as possible. During the pressure test, appropriate measures shall be adopted for the temporary pressure elements welded on the inner vessel to ensure their strength and safety.
4.2.1.1.4 The pressure test site shall have reliable safety protection facilities, which shall be inspected and approved by the technical responsible person of the fabrication unit and the safety management department.
4.2.1.1.5 Continuous pressure shall not be used to maintain the test pressure during the holding period, and during the pressure test, bolts shall not be tightened under pressure or external force shall be applied to the pressure elements.
4.2.1.1.6 During the pressure test, work that is not related to the test shall not be carried out, and irrelevant personnel shall not stay at the test site.
4.2.1.2 Hydraulic test
4.2.1.2.1 Water is generally used as the content for hydraulic test, and other test liquids that will not cause danger may also be used if necessary. During the test, the temperature of the liquid shall be lower than its flash point or boiling point, and reliable safety measures shall be provided.
4.2.1.2.2 The hydraulic test temperature shall meet the requirements of GB/T 150.4 and the design drawings.
4.2.1.2.3 The hydraulic test shall meet the following requirements:
a) air outlet shall be set at the top of the inner vessel, and the air in the vessel shall be exhausted when filling liquid. During the test, the exterior surface of the inner vessel shall be kept dry;
b) If the metal temperature of the inner vessel wall is close to the liquid temperature, the pressure may be slowly increased to the design pressure, and the pressure shall be continuously increased to the specified test pressure after confirming that there is no leakage. The pressure holding time is generally not less than 30 min, and then reduces the pressure to the design pressure, and the pressure holding time shall be long enough to inspect all welded joints and connection parts.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Test methods
5 Inspection rules
