GB/T 24159-2022_English: PDF (GB/T24159-2022)
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| Standard ID | GB/T 24159-2022 (GB/T24159-2022) | | Description (Translated English) | Welded insulated cylinders | | Sector / Industry | National Standard (Recommended) | | Classification of Chinese Standard | J 74 | | Classification of International Standard | 23.020.30 | | Date of Issue | 2022-07-11 | | Date of Implementation | 2023-02-01 | | Older Standard (superseded by this standard) | GB/T 24159-2009 | | Standard ID | GB 24159-2009 (GB24159-2009) | | Description (Translated English) | [GB/T 24159-2009] Welded insulated cylinders | | Sector / Industry | National Standard | | Classification of Chinese Standard | J74 | | Classification of International Standard | 23.020.30 | | Word Count Estimation | 28,281 | | Date of Issue | 2009-06-25 | | Date of Implementation | 2010-04-01 | | Quoted Standard | GB 150; GB/T 228; GB/T 229; GB/T 1804; GB/T 2653; GB/T 3280; GB/T 4237; GB 7144; GB/T 9251; GB/T 12137; GB/T 13005; GB 15384; GB/T 18443.2; GB/T 18443.3; GB/T 18443.4; GB/T 18443.5; JB 4708; JB/T 4730.2; JB/T 4744; JB/T 6896 | | Drafting Organization | Ningbo Mingxin Chemical Machinery Co., Ltd. | | Administrative Organization | National Standardization Technical Committee cylinders | | Regulation (derived from) | Announcement of Newly Approved National Standards No. 8, 2009 (No. 148 overall) | | Proposing organization | National Standardization Technical Committee cylinder (SAC/TC 31) | | Issuing agency(ies) | Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China; Standardization Administration of China | | Summary | This Chinese standard specifies the welding insulation cylinder (hereinafter referred to as cylinders) definitions, symbols, Types, basic parameters, materials, design, manufacture, test methods, inspection rules, marking, packaging, transportation Lohan, storage and other requirements. This standard applies to the normal ambient temperature (-40��C ~ 60��C) under use, storage medium is liquid oxygen, liquid nitrogen, liquid argon, carbon dioxide and nitrous oxide cryogenic liquids, the design temperature not lower than -196��C, nominal volume of 10 L ~ 450 L, working pressure of 0. 2MPa ~ 3. 5 MPa refillable vertical cylinders. |
GB/T 24159-2022
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.30
CCS J 74
Replacing GB/T 24159-2009
Welded insulated cylinders
焊接绝热气瓶
ISSUED ON. JULY 11, 2022
IMPLEMENTED ON. FEBRUARY 01, 2023
Issued by. State Administration for Market Regulation;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative references... 5
3 Terms and definitions... 7
4 Symbols... 8
5 Model naming methods and basic parameters... 9
6 Materials... 10
7 Design... 11
8 Manufacturing... 17
9 Inspection methods... 25
10 Inspection rules... 29
11 Marking, packaging and transportation... 32
12 Exit-factory data... 33
13 Data preservation... 34
Annex A (normative) Maximum allowable filling coefficient... 35
Annex B (normative) Valve inlet and outlet joints... 37
Annex C (Normative) Safe discharge volume and discharge area... 40
Annex D (normative) Vibration test... 47
Annex E (normative) Drop test... 49
Annex F (informative) Product certification... 52
Annex G (informative) Batch inspection quality certificate... 55
Welded insulated cylinders
1 Scope
This document specifies the symbols for welded insulated gas cylinders (hereinafter
referred to as "cylinders"). It specifies cylinder model naming methods, basic
parameters, materials, design, manufacturing, test methods, inspection rules, type test,
marking, packaging, transportation, exit-factory data, data preservation and other
requirements.
This document is applicable to the refillable cylinders that are used under normal
ambient temperature (-40℃~60℃), are used to store liquid oxygen, liquid nitrogen,
liquid argon of which the nominal volume range is 10L~1000L, the nominal volume of
LNG ranges from 150L to 1000L, that the design temperature is not higher than -196℃,
and the nominal working pressure is 0.2MPa~3.5MPa.
For cylinders storing liquid carbon dioxide and liquid nitrous oxide, the manufacture
and inspection can be carried out with reference to this document.
NOTE. All pressures not stated in this document refer to gauge pressure.
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 228.1, Metallic materials - Tensile testing - Part 1.Method of test at room
temperature
GB/T 229, Metallic materials - Charpy pendulum impact test method
GB/T 1804, General tolerances - Tolerances for linear and angular dimensions
without individual tolerance indications
GB/T 2653, Bend test methods on welded joints
GB/T 7144, Coloured cylinder mark for gases
GB/T 9251, Hydrostatic test method for gas cylinders
GB/T 12137, Methods for leakage test of gas cylinders
adiabatic process and the vacuuming process).
3.2 tare of cylinder
The mass of the empty cylinder (for horizontal gas cylinder, it includes frame or support)
that meets the basic functions of filling, storage, transportation, use and safety.
3.3 effective volume
The maximum volume of liquid that the cylinder is allowed to fill.
3.4 heat transfer coefficient
The amount of heat that can be transferred between hot and cold fluids in unit area, unit
temperature difference, unit time, representing the strength of the heat transfer process.
[Source. GB/T 18517-2012, 2.6.2, modified]
3.5 free air
Air at an absolute pressure of 1.01325×105 Pa and a temperature of 15.6°C.
4 Symbols
The following symbols apply to this document.
Di. Inner diameter of head or cylinder body, mm.
D0.Outer diameter of head or cylinder body, mm.
E0.Elastic modulus of the material, MPa.
g. Acceleration of gravity, g=9.81m/s2.
Hi. Inner height of head, equal to the sum of the depth of the inner surface of the head
and the height of the straight edge of the head, mm.
hi. Depth of the inner surface of the head, mm.
h0.Total height of the outer surface of the head, h0=hi+Sn; mm.
k1.Coefficient determined by the ratio of the major and minor axes of the ellipse.
L. Sum of the length of the cylinder, the height of the straight side of each head, and
1/3 of the depth of the inner surface, mm.
P. Nominal working pressure, MPa.
Pb. Design burst pressure of rupture disc, MPa.
Pcr. Critical pressure, MPa.
Pd. Design pressure, MPa.
Pf. Discharge pressure of the safety valve or the design burst pressure of the rupture
disc safety device, MPa.
Pt. Pressure of withstand voltage test, MPa.
Pz. Safety valve setting pressure, MPa.
P1.External pressure, MPa.
R. Outer radius of the spherical shell of the dish-shaped head and the outer radius of
the equivalent spherical shell of the elliptical head, mm.
S. Design wall thickness, mm.
Sb. Measured minimum wall thickness of the cylinder, mm.
Se. Effective thickness, equal to nominal wall thickness minus corrosion allowance and
negative deviation of steel thickness, mm.
Sh. Minimum wall thickness of the head after forming, mm.
Sn. Nominal wall thickness, mm.
σ. Wall stress, MPa.
ΔHi. Height tolerance inside the head, mm.
ΔπDi. Tolerance of the inner circumference of the head, mm.
5 Model naming methods and basic parameters
5.1 Model naming methods
Vertical type is represented by "DPL". Horizontal type is represented by "DPW". The
rest are named according to the method specified in GB/T 15384.When the design is
changed, Roman numerals I, II, III, etc. can be added at the end of the model as serial
numbers.
5.2 Basic parameters
5.2.1 Nominal volume and inner diameter of inner vessel
The nominal volume and inner diameter of the inner vessel shall be selected according
to Table 1.The nominal volume shall be an integer multiple of 5.
7.1.1 Composition
7.1.1.1 A cylinder is mainly composed of an inner vessel, an outer shell, a thermal
insulation system, a connecting piece between the inner vessel and the outer shell, a
valve piping system, a protection device for protecting the valve piping system, a base
and so on. The valve piping system includes valves, instruments, safety relief devices,
pipe fittings, pipes and pipe supports. The protective device shall be a protective cover,
a protective circle (ring), a frame and so on.
7.1.1.2 The main body of the inner vessel shall not exceed three parts, that is, no more
than one longitudinal weld and no more than two circumferential welds.
7.1.2 Connecting piece between inner vessel and outer shell
The stress value of the connecting piece between the inner vessel and the outer shell
shall not be greater than 2/3 of the material's normal temperature yield strength (or
specified plastic extension strength) under the following independent loads.
a) Vertical gas cylinders shall meet the following requirements.
1) The load perpendicular to the cylinder axis shall not be less than the product
of the maximum mass and 2g;
2) The load along the vertical direction of the cylinder axis shall not be lower than
the product of the maximum mass and 3g.
b) Horizontal cylinders shall meet the following requirements.
1) The load perpendicular to the cylinder axis and parallel to the ground shall not
be less than the product of the maximum mass and 2g;
2) The load along the cylinder axis shall not be less than the product of the
maximum mass and 2g;
3) The load perpendicular to the cylinder axis and in the vertical direction shall
not be less than the product of the maximum mass and 3g.
NOTE. "Maximum mass" is the sum of the total mass of the medium (filling the saturated medium
to the effective volume under standard atmospheric pressure), the mass of the inner vessel metal and
the mass of the thermal insulation layer.
7.1.3 Performance indicators
The leakage rate of vacuum interspace and the leakage rate of vacuum interspace are as
specified in Table 4.The static evaporation rate with the nominal working pressure not
greater than 2.4MPa is in accordance with the provisions of Table 4.The static
evaporation rate with the nominal working pressure greater than 2.4MPa is in
accordance with the requirements of the drawings.
7.4.2.1 The cross-sectional area of the relief pipeline connected to the safety pressure
relief device shall not be less than the sum of the inlet area of the safety pressure relief
device. It can ensure that the discharge capacity meets the safety discharge requirements
of gas cylinders.
7.4.2.2 The inlet pipe of the safety pressure relief device shall be located at the top of
the inner vessel. Its lowest point shall be located above the liquid level of 98% of the
nominal volume.
7.4.3 Safety pressure relief device
7.4.3.1 The main safety pressure relief device and the auxiliary safety pressure relief
device shall be arranged in parallel. The main safety pressure relief device shall use
safety valves. The auxiliary safety pressure relief device of LNG is only allowed to use
safety valves. The auxiliary safety pressure relief device for the rest of the medium shall
be safety valve or bursting disc safety device.
7.4.3.2 The set pressure of the main safety relief device (safety valve) shall not be
greater than 1.2 times the nominal working pressure (Pz≤1.2P). The discharge pressure
shall meet the following requirements.
a) In the case of C.1.1, the discharge pressure of liquid oxygen, liquid nitrogen and
liquid argon cylinders shall not be greater than 1.1 times the set pressure;
b) In the case of C.1.2, the discharge pressure of the LNG cylinder shall not be
greater than 1.1 times the set pressure.
7.4.3.3 The auxiliary safety pressure relief device is only applicable to the situation of
C.1.2.It shall meet the following requirements.
a) When a safety valve is used, the set pressure is 1.4 times to 1.6 times the nominal
working pressure (1.4P≤Pz≤1.6P). The discharge pressure shall not be greater than
1.1 times the set pressure;
b) When the bursting disc safety device is used, the design bursting pressure is 1.54
times to 1.76 times the nominal working pressure (1.54P≤Pb≤1.76P).
7.4.3.4 Safety valve shall meet the requirements of GB/T 12243.The reseating pressure
is not less than 90% of the set pressure. Except for the screw thread of the bursting disc
safety device, the rest shall comply with the provisions of GB/T 16918.The safety valve
and bursting disc safety device shall pass the relevant type test verification.
7.5 Pressure relief device of outer shell
The outer shell shall be provided with a pressure relief device to meet the following
requirements.
- The relief pressure shall not be greater than 0.1MPa;;
- The minimum discharge area shall not be less than the product of the nominal
volume of the liner and 0.34mm2/L. The minimum inner diameter is not less than
6mm;
- The double closed structure shall not be used;
- Protective measures shall be taken to avoid injury during discharge.
8 Manufacturing
8.1 Responsibilities of manufacturer
8.1.1 Before the official production of the manufacturer, the documents used for
manufacturing shall have passed the appraisal and approval. Sample cylinders produced
in accordance with this document shall have been verified by type test.
8.1.2 The inspection department of the manufacturer shall conduct inspection and
testing in accordance with the requirements specified in this document and the design
document. Issue corresponding reports. Be responsible for the correctness and
completeness of the report.
8.2 Batching
8.2.1 Manufacture according to inner vessel batches. The material batch number of the
same batch of inner vessel shall not exceed two. Product batches are carried out on the
basis of inner vessel batches. The same inner vessel batch shall be one product batch,
or it can be composed of multiple product batches.
8.2.2 The quantity of a batch of inner vessels shall not be more than 200 (excluding
destructive inspection bottles).
8.3 Material re-inspection
The main material of the inner vessel shall be re-inspected for chemical composition
according to the furnace number. The mechanical properties shall be re-inspected
according to the batch number. The mechanical property test specimens shall be taken
along the direction perpendicular to the rolling direction of the steel plate.
8.4 Mark transplant
The material of the pressure components shall be marked with traceability. In the
manufacturing process, if the original mark is cut off or the material is divided into
several pieces, the manufacturer shall specify the expression of the mark. Before the
material is divided, use a chlorine-free and sulfur-free marker to complete the mark
transplant. Hard stamping shall not be used.
8.5 Unspecified tolerance
Figure 3 -- Schematic diagram of the height of the axial edge and corner of the
girth weld
8.9.3 The components welded on the inner cylinder body shall avoid the longitudinal
and circumferential welded joints of the inner cylinder body.
8.9.4 The connection between the base, frame and hoisting accessories and the cylinder
body shall avoid the longitudinal and circumferential welds of the outer shell.
8.10 Welding
8.10.1 Welding preparation and welding environment
8.10.1.1 Repositories for welding materials shall be kept dry. The relative humidity
shall not be greater than 60%.
8.10.1.2 Welding (including welding rework) shall be carried out on a clean, dry indoor
dedicated site. When any of the following conditions occurs in the welding environment
and there is no effective protective measures, welding shall not be applied.
- When gas shielded welding, the wind speed is greater than 2m/s;
- Relative humidity is greater than 90%;
- The temperature of the weldment is lower than -20℃.
8.10.1.3 When the temperature of the weldment is lower than 0°C, but not lower than -
20°C, it shall be preheated to about 15°C within 100mm of the initial welding point.
8.10.2 Groove requirements
There shall be no cracks, delamination, inclusions and other defects on the groove
surface. Before welding, the groove and other harmful impurities such as oxides, oil
stains and other harmful impurities shall be removed within at least 20mm of the surface
of the base metal on both sides (calculated by the groove edge).
8.10.3 Qualification of inner vessel welding procedure
8.10.3.1 The longitudinal and annular welded joints of inner vessel as well as welded
joints of all components and inner vessel shall be subject to welding procedure
qualification. Welding procedure qualification shall comply with the provisions of this
document and GB/T 33209.
8.10.3.2 For qualification of welding procedures with nominal volume less than or
equal to 100L, sample cylinder can be used for longitudinal seam and circular seam or
flat test piece can be used for longitudinal seam; cylindrical specimen is used for
circumferential seam. Plate specimens can be used when the nominal volume is greater
than 100L.
8.10.3.3 When the thickness of the material is not enough to prepare the impact test
specimen for the welding procedure qualification of the inner vessel of which its
thickness is 2.5mm, it shall use the materials of which the carbon content (mass fraction)
is not less than 0.05% and the thickness is not more than 3.2mm and the same welding
process to weld the specimen cylinder or test piece. Then prepare 2.5mm specimens.
8.10.3.4 The requirements for the welding procedure qualification test results of the
longitudinal and annular welded joints of the inner vessel are as follows.
- No matter where the tensile specimen breaks, the measured tensile strength shall
not be less than the provisions of 6.3 and the requirements of the design documents;
- After the specimen is bent to 180°, there shall be no opening defects in the weld
and heat affected zone on the tensile surface. The edge and corner opening defects
of the specimen are generally not counted. However, the length of angular opening
defects caused by lack of fusion, slag inclusion or other internal defects shall be
counted;
- The average value of Charpy impact energy absorbed energy (KV2) of
10mm×10mm×55mm standard specimen at -192℃ shall not be less than 31J. At
least one specimen is allowed to be less than 31J, but not less than 21.7J. The KV2
indexes of the small-size specimens with widths of 7.5mm, 5mm and 2.5mm are
75%, 50% and 25% of the standard specimens, respectively.
8.10.4 Inner vessel welding
8.10.4.1 Welding equipment, welding marks
Longitudinal and annular welded joints shall use mechanized gas shielded welding.
After welding, the longitudinal and circumferential welded joints shall have traceable
identification and records. The marks shall not be hard-printed.
8.10.4.2 Arc ignition plate and arc quenching plate
When welding, the longitudinal welded joint shall have arc initiation plate and arc
quenching plate. Ring weld joints shall not strike arcs at non-welded locations. It shall
use cutting method to remove the arc striking plate and the arc quenching plate. The
tapping method shall not be used. The cut shall be smoothed after removal.
8.10.4.3 Product welding specimen
8.10.4.3.1 Each batch of inner vessels shall be made according to the material batch
number of the inner vessel cylinder body and the following regulations to make
specimen cylinders or product welding test pieces for mechanical property test and
bending performance test.
a) When the nominal volume is not more than 100L, the longitudinal and
circumferential welded joints shall be made separately;
8.11 Nondestructive testing
8.11.1 The non-destructive testing of the longitudinal and circumferential welded joints
of the inner vessel shall be carried out after the shape, size and appearance comply with
8.10.4.4.
8.11.2 The radiographic inspection technology level is level AB. The test result
evaluation and quality classification are in accordance with the provisions of NB/T
47013.2.The qualification level is not lower than level II.
8.12 Withstand voltage test of inner vessel
8.12.1 The withstand voltage test of inner vessel shall be carried out one by one after
the non-destructive testing is qualified.
8.12.2 The test shall have reliable safety protection measures. It is confirmed and
approved by the technical person in charge of the manufacturer or the person in charge
of safety production.
8.12.3 The test shall use two pressure test instruments with the same range and within
the validity period of the verification. The range is 1.5 times to 3 times the test pressure
(shall be 2 times the test pressure). The accuracy is not less than level 1.6.The diameter
of the mechanical dial is not less than 100mm.
8.12.4 During the test, welded joints with leakage shall be repaired in accordance with
the provisions of 8.10.4.5.After passing the test, perform the withstand voltage test
again.
8.12.5 The pressure shall not drop during the pressure holding check. There shall be no
leakage, visible macroscopic deformation and abnormal sound.
8.13 Surface quality and cleanliness
8.13.1 There shall be no defects on the surface of the sheet that will affect normal use.
For sharp scratches, grinding shall be carried out. The maximum grinding slope shall
be 1.3.Grinding shall be smooth and clean. After grinding, the thickness of the inner
vessel meets the requirements of 7.2.The thickness of the outer shell meets the
requirements of 7.3.
8.13.2 Components forming (or in) a vacuum space shall be cleaned of hydrocarbons
(oil, grease and so on), decontaminated. Good protection measures shall be taken after
disposal. Residual hydrocarbons shall not exceed 125mg/m2 after treatment of parts in
direct contact with oxygen.
8.14 Air tightness test
8.14.1 The air tightness test pressure shall not be lower than the nominal working
pressure.
test method is in accordance with the provisions of GB/T 2653.
9.4 Nondestructive testing
9.4.1 The inspection of the longitudinal and annular welded joints of the inner vessel
shall adopt the radiographic inspection method (film photosensitive, digital imaging,
computer-aided imaging). When using film photosensitive, it shall comply with the
provisions of NB/T 47013.2.When using digital imaging, it shall comply with the
provisions of GB/T 17925 or NB/T 47013.11.When using computer-aided imaging
detection, it shall comply with the provisions of NB/T 47013.14.
9.4.2 The longitudinal and ring welded joints of the inner vessel shall be tested in the
following methods.
a) When the withstand voltage test is carried out with air pressure, the longitudinal
and annular welded joints are 100% radiographically inspected one by one;
b) When hydraulic pressure test is used, the proportion of longitudinal welded joints
extracted shall not be less than 10% of the total number of each batch. There shall
be no less than 2 pieces for 100% radiographic inspection.
9.5 Withstand voltage test of inner vessel
9.5.1 The hydraulic test method is as follows.
- Use clean water with chloride ion content not exceeding 25mg/L;
- The test procedures and steps are carried out in accordance with the provisions of
GB/T 9251;
- After the hydraulic test, the water in the inner vessel and the connecting pipe shall
be drained in time and dried.
9.5.2 The air pressure test method is as follows.
- Use dry and clean air, nitrogen or other inert gases;
- During the test, first slowly increase the pressure to 10% of the test pressure. Hold
the pressure and conduct initial inspection of all welded joints and connections.
After confirming that there is no leakage, continue to increase the pressure to 50%
of the test pressure. If there is no abnormal phenomenon, then increase the pressure
step by step according to 10% of the test pressure until the test pressure is reached.
Hold the pressure at least 30s, and it is fully expanded. Then reduce to the nominal
working pressure. Hold the pressure to check.
9.6 Surface quality and cleanliness
The treatment method of surface quality and cleanliness shall be in accordance with the
......
GB/T 24159-2009 (Renamed from GB 24159-2009)
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.020.30
J 74
GB 24159-2009
Welded Insulated Cylinders
焊接绝热气瓶
ISSUED ON: JUNE 25, 2009
IMPLEMENTED ON: APRIL 01 2010
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, Definitions and Symbols ... 5
4 Types and Basic Parameters... 9
5 Materials ... 11
6 Design ... 13
7 Manufacturing ... 16
8 Test Methods ... 25
9 Inspection Rules ... 29
10 Marking, Packaging, Transportation and Storage ... 32
11 Maintenance ... 33
Appendix A (Normative) Design and Calculation of Safety Relief Capacity . 34
Appendix B (Informative) Test Method of Air Supply ... 37
Appendix C (Informative) Product Certificate ... 39
Appendix D (Informative) Lot Inspection Quality Certificate ... 41
Bibliography ... 43
Welded Insulated Cylinders
1 Scope
This standard specifies the definitions and symbols, types and basic parameters,
materials, design, manufacturing, test methods, inspection rules as well as marking,
packaging, transportation and storage requirements of welded gas cylinders
(hereinafter referred to as cylinders).
This standard is applicable to vertical cylinders, with the storage medium of liquid
oxygen, liquid nitrogen, liquid argon, carbon dioxide and nitrous oxide cryogenic liquid,
design temperature no less than -196℃, nominal volume of 10L~450L and service
pressure of 0.2MPa~3.5MPa respectively, that are used under normal ambient
temperature (-40℃~60℃) and may be filled repeatedly.
2 Normative References
The following normative documents contain provisions which, through reference in this
standard, constitute provisions of this standard. For dated references, subsequent
amendments to (excluding corrigenda), or revisions of, any of these publications do
not apply. However, all parties coming to an agreement according to this standard are
encouraged to study whether the latest editions of these documents apply. For undated
references, the latest editions of the normative document apply.
GB 150 Steel Pressure Vessels
GB/T 228 Metallic Materials - Tensile Testing at Ambient Temperature (GB/T 228-2002,
eqv ISO 6892: 1998)
GB/T 229 Metallic Materials - Charpy Pendulum Impact Test Method (GB/T 229-2007,
ISO 148-1: 2006, MOD)
GB/T 1804 General tolerances - Tolerances for Linear and Angular Dimensions without
Individual Tolerance Indications (GB/T 1804-2000, eqv ISO 2768-1:1989)
GB/T 2653 Methods of Bend and Compression Tests for Welded Joint (GB/T 2653-
2008, ISO 5173: 2000, IDT)
GB/T 3280 Cold Rolled Stainless Steel Plate Sheet and Strip
GB/T 4237 Hot Rolled Stainless Steel Plate Sheet and Strip
GB 7144 Coloured Cylinder Mark for Gases
6.4.5 Braze welding and threaded connection are only allowed to be used for joints
that are indirectly connected to the inner containment vessel.
6.5 Accessories
6.5.1 Safety accessories
6.5.1.1 The inner containment vessel of the cylinder shall be arranged with safety
accessories such as safety valve, bursting disc and pressure gauge and they shall be
directly connected to the inner containment vessel.
6.5.1.2 The selected safety accessories shall meet requirements of relevant
standards and product safety shall be guaranteed through relevant type test.
6.5.1.3 The relief capacity of the safety valve and bursting disc shall meet
requirements of the safety relief capacity. The calculation of the safety relief capacity
is detailed in Appendix A. The opening pressure of the safety valve is less than or equal
to 1.2 times of the service pressure while the burst pressure of the bursting disc is less
than or equal to twice the service pressure.
6.5.1.4 No-oil pressure gauge shall be adopted for the pressure gauge with the
measuring range of (1.5~3) times service pressure and the precision less than Grade
2.5.
6.5.1.5 The cylinder shall be equipped with valves and level gauge that meet
operation requirements such as filling, output and discharge of cryogenic liquid. The
sealing member used for the valve and level gauge components shall be compatible
with the filled media.
6.5.2 Other accessories
6.5.2.1 Structure design and arrangement of the accessories shall be convenient for
operation and weld inspection. The connection weld of the accessories and cylinder
shall be kept clear from the longitudinal and circumferential welds of the cylinder.
Structural shape of the accessories and the connection to the cylinder shall avoid
accumulated liquid.
6.5.2.2 The base shall guarantee the stability of the cylinder while it is erected.
6.5.2.3 Where the total mass after the cylinder is filled with media is greater than
40kg, accessories shall be considered to be hoisted.
6.5.2.4 Protection devices such as cylinder valve, pipeline and safety accessories
shall be considered so as to avoid damage.
7 Manufacturing
7.1 Lot grouping
Cylinders are manufactured according to the lot grouping of the inner containment
vessels and product lot grouping is carried out on the basis of lot grouping for the inner
containment vessels, namely one lot grouping of the inner containment vessels is
permissible to be grouped into several product lots.
7.2 Welding procedure qualification
7.2.1 Where the manufacturing unit of the cylinders changes inner containment
vessel materials, welding materials, welding procedure and welding equipment,
welding procedure qualification shall be carried out before they are put into production.
The welding procedure qualification shall meet not only requirements of this standard,
but also requirements of JB 4708.
7.2.2 Welding procedure qualification may be carried out either on the test plate for
welding procedure qualification or on the inner containment vessel cylinder. The weld
for welding procedure qualification shall be able to represent the principal weld
(longitudinal, circumferential and fillet welds) of the inner containment vessel.
7.2.3 Test plate for welding procedure qualification shall be free from defects such as
undercut, crack, surface gas cavity, welding slag, pit and weld beading after
appearance inspection. The test plate weld shall be subject to 100% radiography
inspection and the inspection results shall meet Grade II requirements of JB/T 4730.2.
7.2.4 Specimen quantity of welded joints for welding procedure qualification is
specified as follows: 2 tensile specimens, 4 transverse bend specimens (two for
surface and back bending respectively) and 6 low-temperature impact specimens
under minimum application temperature of the inner containment vessel material
(three for welds and heat-affected zone respectively).
7.2.5 Where the thickness of inner containment vessel material is greater than or
equal to 2.5mm, the low temperature impact test under minimum application
temperature shall be carried out; where the thickness is less than 2.5mm, the test may
be omitted.
7.2.6 Test result requirements of welding procedure qualification are as follows:
a) No matter where the fracture of the welded joint specimen occurs, the
measured tensile strength shall be greater than or equal to the lower limit of
standard specified value for the inner containment vessel material.
b) The impact value of the low temperature impact specimen for the welded joints
7.7.2 Welding for longitudinal and circumferential welds of the cylinder shall adopt
automatic gas-shielded arc welding, and the welding shall be carried out in strict
accordance with the qualified welding procedure.
7.7.3 Shape and size of welding groove shall meet those specified in the drawing.
The groove surface shall be smooth and clean, and free from any cracks, layers and
occluded foreign substances.
7.7.4 The welding (including repair of weld) shall be carried out in special site indoors,
and the welding site shall be maintained clean and dry; the ground shall be paved with
rubber or wooden sub-plate. The spare parts shall be placed on shelves paved with
wood board.
7.7.5 Welding of cylinder shall be carried out indoor with relative humidity no greater
than 90% and temperature greater than or equal to 0℃.
7.7.6 During welding, arc ignition shall not be carried out on non-welding places of
cylinder. The longitudinal weld shall be provided with run-on plate and arc blowout
plate. Cut off method shall be adopted during removing of run-on plate and arc blowout
plate. The application of knock method is prohibited strictly; moreover, the place of
cutting off shall be rubbed down.
7.8 Weld appearance
7.8.1 Reinforcement for butt weld of inner containment vessel is between
0mm~1.5mm, and the difference between the widest place and narrowest place of the
same weld is not greater than 3mm.
7.8.2 Geometrical shape of fillet shall transit smoothly to that of the base material.
7.8.3 Weld on cylinder shall be free from undercut and incomplete penetration; weld
and heat-affected zone surface shall be free from any crack, gas hole, hollowness and
irregular mutation; splashes on both sides of the weld shall be cleaned up.
7.9 Non-destructive testing
7.9.1 Non-destructive testing shall be carried out according to the requirements for
longitudinal and circumferential joints of inner containment vessel after they are
qualified through appearance inspection. Personnel with "personnel certificate for
inspection and testing of special equipment" of corresponding testing method shall
undertake the non-destructive testing non-destructive testing of cylinder.
7.9.2 100% radiography testing shall be carried out for longitudinal and
circumferential welds of inner containment vessel according to JB/T 4730.2. Weld
defect grade is higher than or equal to Grade II, and quality of radiograph is Grade AB.
7.10 Weld repairing
7.10.1 Weld repairing shall be carried out according to repair process, by personnel
with qualification specified in Article 7.7.1, appearance inspection and non-destructive
testing shall be carried out over again for repair positions according to Sections 7.8
and 7.9.
7.10.2 Repairing time for the position of weld of inner containment vessel should not
exceed 2, otherwise the repair shall be approved by technical director of the
manufacturing unit in advance.
7.10.3 The repairing times and position shall be recorded in the manufacture and
inspection record of product; moreover, they shall be indicated in the product certificate.
7.11 Surface quality and cleanness
7.11.1 Internal and external surfaces of inner containment vessel and outer shell
shall be smooth and free from cracks, double-skin and scratched; otherwise grinding
shall be carried out. The grinding position shall be round, smooth and clean; moreover,
the wall thickness shall be in accordance with the requirements of Article 6.2.2.
7.11.2 Degreasing treatment shall be carried out for internal and external surfaces of
inner containment vessel and all the spare parts having contact with medium, the
relevant requirements in JB/T 6896 shall be met, and moreover, well protection
measures shall be adopted.
7.11.3 Surface and spare parts under vacuum conditions shall be clean and dry, and
free from oil stain and dust.
7.12 Volume and quality
7.12.1 Measured water volume in inner containment vessel of cylinder shall be
greater than or equal to its nominal capacity, and the measured volume may be
replaced with the theoretically calculated value; however, negative deviation shall be
avoided.
7.12.2 After manufacturing of cylinder is finished, net weight shall be determined one
by one.
7.13 Pressure test
7.13.1 Pressure test shall be carried out for inner containment vessel of cylinder one
by one after it is qualified through radiography testing, and hydraulic pressure or air
pressure shall be adopted in the test, moreover, the testing pressure is in accordance
with the requirements of Article 4.2.4. Medium of hydraulic test is clean water with
chloride ion content no greater than 25×10-6; and dry and oil-free air or nitrogen shall
over again after the weld is qualified after repairing; and then vacuum leak test will be
carried out as required after it is qualified in pressure test.
7.17 Vacuum
After the cylinder is filled with liquid nitrogen, vacuum degree of the interspace is
greater than or equal to 2×10-2Pa.
7.18 Tightness test of pipeline
After valve and safety accessories of the cylinder are assembled, tightness test of
pipeline shall be carried out by using dry and oil-free pure air or nitrogen. The test
pressure is the service pressure and the pressure holding duration is greater than or
equal to 1min. Valve, joint and safety accessories shall be free from any leakage.
7.19 Maximum filling capacity
The maximum filling capacity of the cylinder shall be indicated in the design
drawing and the technical documents provided for the user.
8 Test Methods
8.1 Reinspection of materials
Reinspection on chemical compositions and mechanical property of stainless steel of
cylinder shall be carried out according to the methods specified in its material standard
for sampling analysis and test.
8.2 Mechanical property test of template for welding procedure qualification
8.2.1 According to requirements in Article 7.2.2, where the rough specimen is taken
from the template (refer to Figure 6 for its size) for welding procedure qualification,
removed parts on both ends of it shall be greater than or equal to 50mm, rough
specimen is generally taken by machining method. In thermal cutting, the heat-affected
zone shall be removed. Where rough specimen is taken from inner containment vessel
by thermal cutting (refer to Figure 7 for the taken parts), heat-affected zone must not
be remained in the specimen.
8.2.2 Quantity of welded joint specimen for welding procedure qualification is
determined according to the requirements of Article 7.2.4.
8.2.3 Machining shall be carried out in front and back of the weld in specimen to
make it level to base material; cold compression method shall be carried out for jaggy
specimen to make it flatten.
8.2.4 Specimen preparation and test methods
thickness less than 3.2mm and meet the requirements of Sections 5.1, 5.2 and 5.3,
the carbon content of test plate material must not be lower than 0.05%. This furnace
number of test plate may be different from furnace number of inner containment vessel
in the same lot, but the same welding procedure and same heat treatment shall be
adopted.
8.3 Non-destructive inspection of weld
Non-destructive inspection on longitudinal and circumferential weld of inner
containment vessel is carried out according to JB/T 4730.2.
8.4 Mechanical property test of welded joint
8.4.1 The welded joint specimen is taken from inner containment vessel: one tensile
force specimen, one horizontal surface bending specimen and one back bending
specimen are taken respectively from longitudinal weld as well as three low
temperature impact specimens (the notch is in weld center). If circumferential weld and
longitudinal weld are made by different welding methods (or welding procedures),
same quantity of specimen shall also be taken from circumferential weld, taking parts
of test plate and rough specimen see Figure 7.
8.4.2 Welded joint specimen is taken from product weld test plate: one piece of
tensile specimen, one horizontal surface bending specimen and one back bending
specimen, three pieces of impact specimens (notch is in weld center), taking parts of
rough specimen are detailed in Figure 6.
8.4.3 Rough specimen taking method from inner containment vessel of cylinder or
product weld test plate shall meet the requirements of Article 8.2.1.
8.4.4 Processing of welded joint specimen shall meet the requirements of Article
8.2.3.
8.4.5 Preparation and test methods of welded joint specimen
Tensile force of welded joint as well as the preparation of bending specimen and impact
specimen and its test shall be carried out according to the requirements of Article 8.2.4.
8.5 Pressure test of inner containment vessel
Hydraulic test of inner containment vessel is carried out according to requirements in
GB/T 9251, the pressure boosting procedure of pneumatic testing shall be carried out
by reference to "Technologic Supervision Regulations On Safety Of Pressure Vessels".
8.6 Tightness test of pipeline
Tightness test of pipeline shall be carried out according to GB/T 12137; the test
medium shall be dry, clean and oil-free air or nitrogen.
8.13 Leak and outgassing rate test
Test method of leak and outgassing rate is in accordance with those specified in GB/T
18443.4.
8.14 Static evaporation rate test
Test of static evaporation rate is carried out according to the requirements of GB/T
18443.5.
8.15 Air supply test
Air supply may be tested according to Appendix B.
9 Inspection Rules
9.1 Material inspection
9.1.1 As for the material of inner containment vessel, the manufacturing unit shall, in
accordance with methods specified in Section 8.1, carry out verification analysis for its
chemical composition according to the furnace No. and verification test for its
mechanical property according to the lot No.
9.1.2 As for the material of inner containment vessel, the reinspection results of its
chemical composition and mechanical property tests shall meet the requirements of
Sections 5.2 and 5.3. If any imported material is adopted, it shall meet the requirements
of Article 5.1.1.
9.2 Delivery inspection
9.2.1 One-by-one inspection
One-by-one inspection shall be carried out according to those specified in Table 7.
9.2.2 Lot inspection
9.2.2.1 Lotting and sampling rules
No more than 200 inner containment vessels are taken as one lot and 1 is sampled
from each lot to carry out mechanical property test for welded joints.
9.2.2.2 Inspection items of the cylinder lot shall be in accordance with those specified
in Table 7, thereinto, for the static evaporation rate test, no less than 3 from each lot
shall be sampled at random.
9.2.3 Reinspection rule
11 Maintenance
11.1 The property unit of the cylinder shall be responsible for the safety of the in-
service product. The property unit and the using unit shall correctly use according to
requirements of the operating instruction, regularly inspect the safety accessories such
as pressure gauge, safety valve, bursting disc and governor, and make good records.
11.2 During the operation, if the insulation property is degraded or abnormal
phenomena endangering the safety take place, proper measures shall be immediately
taken to lead the filled liquid medium out of the empty cylinder and stop using the
cylinder. Meanwhile, the local inspection unit or the manufacturing unit shall be
immediately informed to handle it.
11.3 If quality problems take place in the maintenance period of the manufacturing
unit, relevant maintenance unit shall be responsible for maintenance; if not, the
property unit, the using unit and the manufacturing unit shall settle them through
negotiation.
11.4 After the repairing, the repair unit shall make a permanent mark on the cylinder,
indicate the maintenance completion time and make good records on files.
11.5 Delivery documents
Before the delivery, at least one of the following documents shall be provided with:
a) Product Certificate, see Appendix C;
b) Lot Inspection Quality Certificate, see Appendix D;
c) Operating Instruction.
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