GB/T 24918-2010 PDF in English
GB/T 24918-2010 (GB/T24918-2010, GBT 24918-2010, GBT24918-2010)
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Cryogenic emergency shutoff valve
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GB/T 24918-2010: PDF in English (GBT 24918-2010) GB/T 24918-2010
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.060.99
J 16
Cryogenic emergency shutoff valve
ISSUED ON: AUGUST 09, 2010
IMPLEMENTED ON: DECEMBER 31, 2010
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 ... 5
4 Technical requirements ... 5
5 Test methods ... 10
6 Inspection rules ... 13
7 Marking ... 15
8 Supply requirements ... 15
Cryogenic emergency shutoff valve
1 Scope
This Standard specifies the terminology, technical requirements, test methods,
inspection rules, appearance, marking and supply requirements of cryogenic emergency
shutoff valve (hereinafter referred to as emergency shutoff valve).
This Standard applies to nominal dimensions DN 15 ~ DN 200, nominal pressure PN
16 ~ 63, operating temperature -196 ℃ ~ -29 ℃, emergency automatic cut-off
temperature 70 ℃ ± 5 ℃, and using low-temperature media of oxygen, nitrogen, argon,
natural gas, ethylene (O2, N2, Ar, CNG, C2H4) and other gases and liquids.
2 Normative references
The terms in the following documents become the terms of this Standard by reference
to this Standard. For dated references, all subsequent amendments (not including errata
content) or revisions do not apply to this standard. However, parties to agreements that
are based on this Standard are encouraged to study whether the latest versions of these
documents can be used. For undated references, the latest edition applies to this
Standard.
GB/T 229, Metallic materials - Charpy pendulum impact test method (GB/T 229-
2007, ISO 148-1:2006, MOD)
GB/T 1047, Pipework components - Definition and selection of nominal size
(GB/T 1047-2005, ISO 6708:1995, MOD)
GB/T 1048 Pipework components - Definition and selection of nominal pressure
(GB/T 1048-2005, ISO/CD 7268:1996, MOD)
GB/T 1220, Stainless steel bars
GB/T 1222, Spring steels
GB/T 4240, Stainless steel wires (GB/T 4240-1993, neq JIS G4309:1988)
GB/T 9113 (all parts), Integral steel pipe flanges
GB/T 12220, General purpose industrial valves - Marking (GB/T 12220-1989, idt
ISO 5209:1977)
GB/T 12221, Metal calves - Face to face, end to end, center to face and center to
end dimensions (GB/T 12221-2005, ISO 5752:1982, MOD)
GB/T 12224, General requirements for industrial steel valves (GB/T 12224-2005,
AST MB 16.34a-1998, NEQ)
GB/T 12230, General purpose industrial valves - Specification of stainless steel
castings
GB/T 12235, Steel globe valves and lift check valve for petroleum petrochemical
and allied industries
GB/T 24925, Low temperature valve - Technical specifications
JB/T 106, Valves marking and paint
JB/T 6697, Tractors and machinery for agriculture and forestry - Electrical
equipment - Basic specifications
JB/T 6902-2008, Methods for liquid penetrant examination of valves
JB/T 7248, Technical specification for low temperature service steel casting for
valves
JB/T 7927, Valve cast steel visual quality requirements
JB/T 7928, Industrial valves - Delivery specification
JB/T 9218-2007, Non-destructive testing - Penetrant testing
3 Terms
The following terms and definitions are applicable to this Standard.
3.1
emergency shut-off valve
Value – installed on a tanker (tank truck), storage tank or pipeline – that can be quickly
shut off manually or automatically in the event of an accident.
4 Technical requirements
4.1 General requirements
In addition to complying with the provisions of this Standard, emergency shut-off
valves shall also comply with the provisions of GB/T 24925.
4.2 Parameters
4.4 Structural length
The structural length of the emergency shut-off valve shall be in accordance with the
provisions of GB/T 12221, or in accordance with the requirements of the order contract.
4.5 Appearance
Except for austenitic stainless-steel valves, the non-machined outer surfaces of other
metals shall be painted. The paint layer shall use coating of durability. The coating at
the marking shall ensure that the marking is clear; the color of the paint shall be in
accordance with JB/T 106. Special requirements are specified in the order contract.
4.6 Connection form
The connection forms of emergency shut-off valve shall be welded connection or
flanged connection. The welded connection shall comply with the provisions of GB/T
12224, and the flanged connection shall comply with the provisions of GB/T 9113.
Special requirements are specified in the order contract.
4.7 Cleaning requirements
All parts of the emergency shut-off valve shall be cleaned before assembly.
4.8 Performance requirements
4.8.1 Operating performance
Operate separately at normal and low temperatures. The emergency shut-off valve shall
move flexibly without jamming or crawling.
4.8.2 Sealing performance
4.8.2.1 The sealing performance test shall be subjected separately to low-pressure and
high-pressure sealing tests. After the low-pressure sealing test is qualified, perform the
high-pressure sealing test.
4.8.2.2 Normal temperature sealing performance test
Test pressure: low pressure is 0.1MPa, high pressure is 1.1 times the nominal pressure
of the valve, the test medium is nitrogen, the duration is 15 minutes, and there must be
no leakage.
4.8.2.3 Low temperature sealing performance
Test pressure: low pressure is 0.1 MPa, high pressure is 1.1 times the nominal pressure
of the valve, the test medium is helium, the duration is 15 minutes each, and the leakage
is not allowed to be greater than 2×DN, in mL/min.
4.8.3 Shell strength
4.8.3.1 For emergency shut-off valves used in LNG tank containers, the strength test
pressure of the shell (valve body, valve cover) shall be 4 times the tank design pressure;
for emergency shut-off valves used in other situations, the strength test pressure of the
shell (valve body, valve cover) is 1.5 times the nominal pressure.
4.8.3.2 After passing the shell strength test, the emergency shut-off valve shall have no
structural damage, and there shall be no visible leakage on the pressure-bearing wall
and the connection between the valve body and the valve cover.
4.8.4 Emergency shutoff time
The emergency shut-off valve shall close within 10 seconds from the time it starts to
close.
4.8.5 Vibration resistance
The emergency shut-off valve for tankers and tank trucks shall be resistant to vibration
and shall comply with the requirements of JB/T 6697.
4.8.6 Overtemperature shutdown
The fusible plug shall be able to melt when the ambient temperature reaches 70 ℃ ±
5 ℃, and the emergency shut-off valve shall automatically cut off.
4.8.7 Natural closure
For valves that rely on air pressure to open and close, when fully open, they shall be
able to remain open for 48 hours and will not naturally close.
4.8.8 Anti-static
When the power supply voltage does not exceed 12 V, the resistance of the anti-static
circuit of the valve disc, valve stem and valve body shall be less than 10 Ω.
4.8.9 No-load operating life
The emergency shut-off valve shall be able to meet the performance requirements after
opening and closing 2 000 times under no load.
4.9 Parts
4.9.1 Main pressure parts shall be inspected for flaw detection. Casting defects shall not
be lower than Level 2 (including Level 2) in JB/T 6902-2008, and forging defects shall
not be lower than Level 2 (including Level 2) in JB/T 9218-2007.
4.9.2 The valve body, valve cover, valve disc, valve seat, valve stem and other parts
shall be cryogenically treated. The valve body shall be cryogenically treated before
assembly and grinding, and the rest shall be carried out before finishing.
For emergency shut-off valves used in LNG tank containers, the strength test pressure
of the shell (valve body, valve cover) shall be 4 times the tank design pressure; for
emergency shut-off valves used in other situations, the strength test pressure of the shell
(valve body, valve cover) is 1.5 times the nominal pressure.
5.1.2 Test duration
The test duration is as specified in Table 3.
Table 3 – Test duration
Nominal size DN ≤50 65 ~ 200
Test duration/min ≥10 ≥15
5.1.3 Test procedure
Fill the body cavity of each pressure test piece with the test medium (water); gradually
pressurize to the test pressure; maintain for the specified duration; then, inspect the
pressure test piece.
5.1.4 Test medium
The test medium is water. For stainless steel valves, the chloride ion content of the test
medium shall not exceed 25×10-6.
5.2 Sealing performance test
Conduct the sealing performance test at normal temperature and low temperature,
respectively. Perform the low temperature test after passing the normal temperature test.
The low temperature test temperature is -196 ℃.
5.2.1 External leakage test
5.2.1.1 The test pressure is 1.1 times the nominal pressure of the valve.
5.2.1.2 The test medium is nitrogen at normal temperature and helium at low
temperature.
5.2.1.3 During the test, the valve is in an open state, the outlet end is closed, pressure is
introduced from the inlet end, and there must be no leakage at the packing and the
connection between the valve body and the valve cover.
5.2.2 Air tightness test
5.2.2.1 The air tightness test shall be subjected separately to low pressure and high
pressure tests. After the low pressure air tightness test is qualified, perform the high
pressure air tightness test.
5.2.2.2 The air tightness test pressure is the maximum working pressure (high pressure)
and 0.1 MPa (low pressure) respectively, and the actuator test pressure is the maximum
working air source pressure.
5.2.2.3 The test medium is nitrogen at normal temperature and helium at low
temperature.
5.2.2.4 During the test, the valve is in a closed state, pressure is introduced from the
inlet end, and the leakage amount is in accordance with the provisions of 4.8.2.
5.3 Action test
Use nitrogen or helium to apply the same test pressure as the maximum working
pressure in the direction of medium flow. When the emergency shut-off valve starts to
operate, it must be closed within 10 seconds.
5.4 Natural closure test
For emergency shut-off valves that rely on air pressure to open and close, open the valve,
stop adding pressure to the system, and the valve shall meet the requirements of 4.8.7.
5.5 Vibration test
5.5.1 With the valve in a closed state, conduct a vibration test in accordance with the
provisions of JB/T 6697.
5.5.2 After the valve undergoes the vibration test, first conduct an external inspection.
The parts shall be free of damage and the fasteners shall not be loose. The subsequent
test shall meet the requirements of 5.2 and 5.3.
5.6 Anti-static test
Select a valve for testing and use a digital multimeter or electric bridge to measure the
resistance between the valve disc, valve stem and valve body. The test results shall meet
the requirements of 4.8.8.
5.7 No-load operating life test
The valve shall be subjected to repeated operating life tests under no load, and sealing
performance test shall be conducted after each opening and closing of 500, 1 000, 1 300,
1 600, 1 800 and 2 000 times. The test results shall meet the requirements of 4.8.2.
5.8 Fusible plug test
5.8.1 Fusible plug melting test
The test device is shown in Figure 3. Apply a pressure of 0.3 MPa to the fusible plug.
When it reaches 70 ℃ ± 5 ℃, the fusible alloy in the fusible plug shall be able to melt.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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