Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 24925-2010 Gryogenic valve technical specifications. In addition to a number of editorial changes, the following main technical changes have been made with respect to GB/T 24925-2010:
——The terms “cryogenic treatment”, “drip plate”, “CWP” “internal cooling cycle”, and “cold box” are added; the term "bonnet extension” (颈部伸长量 in Chinese) is modified to "bonnet extension” (阀盖加长颈 in Chinese) (see Clause 3 of this edition and Clause 3 of Edition 2010).
——In Clause 4, axial flow check valve, top-mounted fixed ball valve, top-mounted floating ball valves and top-mounted eccentric butterfly valves are added; "cryogenic worm and wheel drive butterfly valve" is modified to "eccentric butterfly valve" (see Clause 4 of this edition and Clause 4 of Edition 2010).
——The requirements for valves’ pressure and temperature rating, connection type, drip plate, structure length, minimum diameter of the seat, installation direction, identification of pressure relief mode, etc., are added in 5.1 (see 5.1 of this edition and 5.1 of Edition 2010).
——"Performance" is added; the leak rate of the sealing test is modified; the fugitive emission test, low-temperature cycle life test, etc. are added for middle flange and valve stem (see 5.1 of this edition and Table 2 of Edition 2010).
——The requirements for minimum wall thickness of valve body and flanges are added (see 5.1.4 and 5.3.2 of this edition and 5.2 of Edition 2010).
——The requirements for the minimum elongation of bonnet extension (including those of low temperature valves for cold box and not for cold box) and for thermal insulation layer and drip plate are added (see 5.4.1 and 5.4.5 of this edition and 5.3 of Edition 2010).
——The requirements for torque and blow-out proof structure of valve stem are added, and the requirements for dangerous section setting are modified (see 5.5 of this edition and 5.4 of Edition 2010).
——"Discs" is changed to "Opening and closing parts (disc, valve plate, ball) and valve seats", in which the requirements for ball valve and butterfly valve are added (see 5.6 of this edition and 5.5 of Edition 2010).
——"Packing box” is modified to "Packing and packing box"; the requirements for packing and packing box structure are added (see 5.7 of this edition and 5.6 of Edition 2010).
——The requirements for middle flange seal are added (see 5.8 of this edition).
——"Operating force" is modified to "Operation", in which "Maximum operating force allowed at the moment of valve opening or closing", limit requirements and "Driving device and operation" are added (see 5.9 of this edition and 5.7 of Edition 2010).
——The requirements for mechanical properties and chemical composition of materials are added; the requirements for the welding parts of pressure-containing components of valves and for materials of bonnet fastenings are added (see 5.10.3, 5.10.4 and 5.10.5 of this edition).
——The requirements for appearance quality and defect treatment of steel casting are added (see 5.11 of this edition).
——The subclause related to non-destructive test is modified, with detailed requirements provided on the basis of the original one (see 5.13 of this edition and 5.11 of Edition 2010).
——"Test methods” are modified to "inspection and test methods"; Annex B is added, and corresponding inspection and test methods are added or deleted according to technical requirements (see Clause 6 and Annex B of this edition and Clause 6 of Edition 2010).
——The inspection items and technical requirements for low temperature valves in the inspection rules are modified, and the sampling method is deleted (see Table 10 of this edition and Clause 7 of Edition 2010).
——Clause 8 “Marking” is modified (see clause 8 of this edition and Clause 8 of Edition 2010).
——"Shipping and storage" is modified to "Painting, packaging, transportation and storage", with contents modified accordingly (see Clause 9 of this edition and Clause 9 of Edition 2010).
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of National Technical Committee 188 on Valve of Standardization Administration of China (SAC/TC 188).
The previous edition of this standard is as follows:
——GB/T 24925-2010.
Low temperature valve - Technical specifications
1 Scope
This standard specifies the structural types, technical requirements, test methods, inspection rules, marking, painting, packaging, transportation and storage of low temperature valve (hereinafter referred to as “valve”).
This standard is applicable to the flanged, wafer and welded low-temperature gate valves, stop valves, check valves, ball valves and butterfly valves with nominal pressures of PN16~PN400 and nominal dimension of DN15~DN1,200, or those with pressure class of 150~2,500, nominal dimension of NPS 1/2~NPS 48 and medium temperature of -196℃~-29℃.
This standard may be used for reference for other low temperature valves.
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 229 Metallic materials - Charpy pendulum impact test method
GB/T 9113 Integral steel pipe flanges
GB/T 12220 Industrial valves - Marking
GB/T 12221 Metal calves - Face to face, end to end, center to face and center to end dimensions
GB/T 12222 Multi-turn valve actuator attachments
GB/T 12223 Part-turn valve actuator attachments
GB/T 12224 General requirements for industrial steel valves
GB/T 12225 General purpose industrial valves - Specification of copper alloy castings
GB/T 12234 Bolted bonnet steel gate valves for petroleum and natural gas industries
GB/T 12235 Steel globe valves and lift check valve for petroleum petrochemical and allied industries
GB/T 12236 Steel swing check valve for petroleum petrochemical and allied industries
GB/T 12237 Steel ball valves for petroleum petrochemical and allied industries
GB/T 12238 Flanged and wafer resilient seal butterfly valves
GB/T 13402 Large diameter steel pipe flanges
GB/T 21387 Axial flow check valve
GB/T 22652 Overlaying-welding procedure qualification for valves sealing face
GB/T 26479 Fire test for soft-seated quarter-turn valves
GB/T 26480 Valve inspection and testing
GB/T 26482 Fire type-testing requirement for check valves
GB/T 26640 Specification for minimal thickness of the shell of valves
GB/T 28776 Steel gate, globe and check valve for the petroleum and natural gas industries (for sizes DN100 and smaller)
JB/T 6438 Technical requirements for plasma arc overlaying welding for valve sealing surface
JB/T 6439-2008 Methods of magnetic examination for valves
JB/T 6440-2008 Methods of radiographic examination for steel castings valves
JB/T 6903-2008 Methods for ultrasonic examination of steel forgings for valves
JB/T 7248 Technical specification for low temperature service steel casting for valves
JB/T 7746 Compact steel valves
JB/T 7927 Valve cast steel visual quality requirements
JB/T 7928 Industrial valves - Delivery specification
JB/T 8527 Metallic sealing butterfly valve
JB/T 12003 Specification for valve cryogenic test rig
JB/T 12622 Liquefied natural gas valves - Performance testing
NB/T 47009 Low alloy steel forgings for low temperature pressure equipment
NB/T 47010 Stainless and heat-resisting steel forgings for pressure equipments
NB/T 47013.2-2015 Nondestructive testing of pressure equipment - Part 2: Radiographic testing
NB/T 47013.4 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing
NB/T 47013.5-2015 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
NB/T 47014 Welding procedure qualification for pressure equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bonnet extension
part between the top of the bonnet bracket and the bottom of the bonnet packing box
part between the top of the lower bushing of the bonnet and the bottom of the packing box for the valve with lifting stem
part between the top of the lower bonnet bearing and the bottom of the packing box for quarter-turn valve
3.2
cryogenic treatment
treatment process as following: Immerse the parts in liquid nitrogen for cooling until their temperature is stable at -196℃, then maintain such temperature for 2h~4h according to the thickness of the parts, and then take them out of the box to return to room temperature naturally
3.3
drip plate
mesh plate arranged at the bonnet extension to prevent condensed water from entering the insulation layer of the extended bonnet
3.4
cold working pressure
CWP
maximum allowable working pressure of valve at medium temperature of -20℃~38℃
3.5
internal cooling cycle
method to reduce the temperature of the test valve by making the low-temperature medium flow through the test valve
3.6
cold box
box containing equipment lower than ambient temperature and filled with insulation material
4 Structural types
The typical structures of low temperature valves are shown in Figure 1 ~ Figure 10.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Structural types
5 Technical requirements
5.1 General requirements
5.2 Performance
5.3 Valve body
5.4 Bonnet
5.5 Valve stem
5.6 Opening and closing parts and valve seats
5.7 Packing and packing box
5.8 Middle flange seal
5.9 Operation
5.10 Materials
5.11 Appearance quality of steel casting
5.12 Defect disposal
5.13 Non-destructive testing
6 Test methods
6.1 Marking inspection
6.2 Appearance quality of steel castings
6.3 Dimension inspection
6.4 Chemical composition
6.5 Mechanical properties
6.6 Cold test
6.7 Low temperature test
6.8 Low-temperature cycle life test
6.9 Non-destructive testing
6.10 Anti-static test
7 Inspection rules
7.1 Inspection items
7.2 End-of-manufacturing inspection
7.3 Type test
8 Marking
9 Painting, packaging, transportation and storage
Annex A (Informative) Recommended material of low temperature valve
Annex B (Informative) Schematic diagram for internal cooling cycle
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 24925-2010 Gryogenic valve technical specifications. In addition to a number of editorial changes, the following main technical changes have been made with respect to GB/T 24925-2010:
——The terms “cryogenic treatment”, “drip plate”, “CWP” “internal cooling cycle”, and “cold box” are added; the term "bonnet extension” (颈部伸长量 in Chinese) is modified to "bonnet extension” (阀盖加长颈 in Chinese) (see Clause 3 of this edition and Clause 3 of Edition 2010).
——In Clause 4, axial flow check valve, top-mounted fixed ball valve, top-mounted floating ball valves and top-mounted eccentric butterfly valves are added; "cryogenic worm and wheel drive butterfly valve" is modified to "eccentric butterfly valve" (see Clause 4 of this edition and Clause 4 of Edition 2010).
——The requirements for valves’ pressure and temperature rating, connection type, drip plate, structure length, minimum diameter of the seat, installation direction, identification of pressure relief mode, etc., are added in 5.1 (see 5.1 of this edition and 5.1 of Edition 2010).
——"Performance" is added; the leak rate of the sealing test is modified; the fugitive emission test, low-temperature cycle life test, etc. are added for middle flange and valve stem (see 5.1 of this edition and Table 2 of Edition 2010).
——The requirements for minimum wall thickness of valve body and flanges are added (see 5.1.4 and 5.3.2 of this edition and 5.2 of Edition 2010).
——The requirements for the minimum elongation of bonnet extension (including those of low temperature valves for cold box and not for cold box) and for thermal insulation layer and drip plate are added (see 5.4.1 and 5.4.5 of this edition and 5.3 of Edition 2010).
——The requirements for torque and blow-out proof structure of valve stem are added, and the requirements for dangerous section setting are modified (see 5.5 of this edition and 5.4 of Edition 2010).
——"Discs" is changed to "Opening and closing parts (disc, valve plate, ball) and valve seats", in which the requirements for ball valve and butterfly valve are added (see 5.6 of this edition and 5.5 of Edition 2010).
——"Packing box” is modified to "Packing and packing box"; the requirements for packing and packing box structure are added (see 5.7 of this edition and 5.6 of Edition 2010).
——The requirements for middle flange seal are added (see 5.8 of this edition).
——"Operating force" is modified to "Operation", in which "Maximum operating force allowed at the moment of valve opening or closing", limit requirements and "Driving device and operation" are added (see 5.9 of this edition and 5.7 of Edition 2010).
——The requirements for mechanical properties and chemical composition of materials are added; the requirements for the welding parts of pressure-containing components of valves and for materials of bonnet fastenings are added (see 5.10.3, 5.10.4 and 5.10.5 of this edition).
——The requirements for appearance quality and defect treatment of steel casting are added (see 5.11 of this edition).
——The subclause related to non-destructive test is modified, with detailed requirements provided on the basis of the original one (see 5.13 of this edition and 5.11 of Edition 2010).
——"Test methods” are modified to "inspection and test methods"; Annex B is added, and corresponding inspection and test methods are added or deleted according to technical requirements (see Clause 6 and Annex B of this edition and Clause 6 of Edition 2010).
——The inspection items and technical requirements for low temperature valves in the inspection rules are modified, and the sampling method is deleted (see Table 10 of this edition and Clause 7 of Edition 2010).
——Clause 8 “Marking” is modified (see clause 8 of this edition and Clause 8 of Edition 2010).
——"Shipping and storage" is modified to "Painting, packaging, transportation and storage", with contents modified accordingly (see Clause 9 of this edition and Clause 9 of Edition 2010).
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of National Technical Committee 188 on Valve of Standardization Administration of China (SAC/TC 188).
The previous edition of this standard is as follows:
——GB/T 24925-2010.
Low temperature valve - Technical specifications
1 Scope
This standard specifies the structural types, technical requirements, test methods, inspection rules, marking, painting, packaging, transportation and storage of low temperature valve (hereinafter referred to as “valve”).
This standard is applicable to the flanged, wafer and welded low-temperature gate valves, stop valves, check valves, ball valves and butterfly valves with nominal pressures of PN16~PN400 and nominal dimension of DN15~DN1,200, or those with pressure class of 150~2,500, nominal dimension of NPS 1/2~NPS 48 and medium temperature of -196℃~-29℃.
This standard may be used for reference for other low temperature valves.
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 229 Metallic materials - Charpy pendulum impact test method
GB/T 9113 Integral steel pipe flanges
GB/T 12220 Industrial valves - Marking
GB/T 12221 Metal calves - Face to face, end to end, center to face and center to end dimensions
GB/T 12222 Multi-turn valve actuator attachments
GB/T 12223 Part-turn valve actuator attachments
GB/T 12224 General requirements for industrial steel valves
GB/T 12225 General purpose industrial valves - Specification of copper alloy castings
GB/T 12234 Bolted bonnet steel gate valves for petroleum and natural gas industries
GB/T 12235 Steel globe valves and lift check valve for petroleum petrochemical and allied industries
GB/T 12236 Steel swing check valve for petroleum petrochemical and allied industries
GB/T 12237 Steel ball valves for petroleum petrochemical and allied industries
GB/T 12238 Flanged and wafer resilient seal butterfly valves
GB/T 13402 Large diameter steel pipe flanges
GB/T 21387 Axial flow check valve
GB/T 22652 Overlaying-welding procedure qualification for valves sealing face
GB/T 26479 Fire test for soft-seated quarter-turn valves
GB/T 26480 Valve inspection and testing
GB/T 26482 Fire type-testing requirement for check valves
GB/T 26640 Specification for minimal thickness of the shell of valves
GB/T 28776 Steel gate, globe and check valve for the petroleum and natural gas industries (for sizes DN100 and smaller)
JB/T 6438 Technical requirements for plasma arc overlaying welding for valve sealing surface
JB/T 6439-2008 Methods of magnetic examination for valves
JB/T 6440-2008 Methods of radiographic examination for steel castings valves
JB/T 6903-2008 Methods for ultrasonic examination of steel forgings for valves
JB/T 7248 Technical specification for low temperature service steel casting for valves
JB/T 7746 Compact steel valves
JB/T 7927 Valve cast steel visual quality requirements
JB/T 7928 Industrial valves - Delivery specification
JB/T 8527 Metallic sealing butterfly valve
JB/T 12003 Specification for valve cryogenic test rig
JB/T 12622 Liquefied natural gas valves - Performance testing
NB/T 47009 Low alloy steel forgings for low temperature pressure equipment
NB/T 47010 Stainless and heat-resisting steel forgings for pressure equipments
NB/T 47013.2-2015 Nondestructive testing of pressure equipment - Part 2: Radiographic testing
NB/T 47013.4 Nondestructive testing of pressure equipments - Part 4: Magnetic particle testing
NB/T 47013.5-2015 Nondestructive testing of pressure equipments - Part 5: Penetrant testing
NB/T 47014 Welding procedure qualification for pressure equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bonnet extension
part between the top of the bonnet bracket and the bottom of the bonnet packing box
part between the top of the lower bushing of the bonnet and the bottom of the packing box for the valve with lifting stem
part between the top of the lower bonnet bearing and the bottom of the packing box for quarter-turn valve
3.2
cryogenic treatment
treatment process as following: Immerse the parts in liquid nitrogen for cooling until their temperature is stable at -196℃, then maintain such temperature for 2h~4h according to the thickness of the parts, and then take them out of the box to return to room temperature naturally
3.3
drip plate
mesh plate arranged at the bonnet extension to prevent condensed water from entering the insulation layer of the extended bonnet
3.4
cold working pressure
CWP
maximum allowable working pressure of valve at medium temperature of -20℃~38℃
3.5
internal cooling cycle
method to reduce the temperature of the test valve by making the low-temperature medium flow through the test valve
3.6
cold box
box containing equipment lower than ambient temperature and filled with insulation material
4 Structural types
The typical structures of low temperature valves are shown in Figure 1 ~ Figure 10.
Contents of GB/T 24925-2019
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Structural types
5 Technical requirements
5.1 General requirements
5.2 Performance
5.3 Valve body
5.4 Bonnet
5.5 Valve stem
5.6 Opening and closing parts and valve seats
5.7 Packing and packing box
5.8 Middle flange seal
5.9 Operation
5.10 Materials
5.11 Appearance quality of steel casting
5.12 Defect disposal
5.13 Non-destructive testing
6 Test methods
6.1 Marking inspection
6.2 Appearance quality of steel castings
6.3 Dimension inspection
6.4 Chemical composition
6.5 Mechanical properties
6.6 Cold test
6.7 Low temperature test
6.8 Low-temperature cycle life test
6.9 Non-destructive testing
6.10 Anti-static test
7 Inspection rules
7.1 Inspection items
7.2 End-of-manufacturing inspection
7.3 Type test
8 Marking
9 Painting, packaging, transportation and storage
Annex A (Informative) Recommended material of low temperature valve
Annex B (Informative) Schematic diagram for internal cooling cycle
