GB/T 12238-2008 PDF English
US$105.00 · In stock · Download in 9 secondsGB/T 12238-2008: Flanged and wafer resilient seal butterfly valves Delivery: 9 seconds. True-PDF full-copy in English & invoice will be downloaded + auto-delivered via email. See step-by-step procedureStatus: Valid GB/T 12238: Evolution and historical versions
| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB/T 12238-2008 | English | 105 |
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Flanged and wafer resilient seal butterfly valves
| Valid |
| GB/T 12238-1989 | English | 519 |
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General purpose industrial valves--Flanged and wafer butterfly valves
| Obsolete |
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GB/T 12238-2008: Flanged and wafer resilient seal butterfly valves---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT12238-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 23.060.99
J 16
Replacing GB/T 12238-1989
Flanged and wafer resilient seal butterfly valves
Issued on. DECEMBER 23, 2008
Implemented on. JULY 01, 2009
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of China.
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative references... 5
3 Structural form... 6
4 Technical requirements... 9
5 Materials... 14
6 Test methods... 15
7 Inspection rules... 16
8 Marking... 18
9 Painting and storage... 19
Annex A (informative) Calculation of minimum wall thickness of valve body... 20
1 Scope
This Standard specifies the structural form, technical requirements, materials, test
methods and inspection rules, marking, painting, packaging, storage and transportation
of flanged and wafer resilient seal butterfly valves.
This Standard is applicable to. flanged resilient seal butterfly valves with nominal
pressure not greater than PN25 and nominal size of DN50~DN4000; wafer resilient seal
butterfly valves with nominal pressure not greater than PN16 and nominal size of
DN50~DN1200.
The medium is non-corrosive liquids and gases. In the fully open position, the flow rate
of the medium in the pipe is not greater than 5 m/s.
2 Normative references
The provisions in following documents become the provisions of this Standard through
reference in this Standard. For dated references, the subsequent amendments (excluding
corrigendum) or revisions do not apply to this Standard, however, parties who reach an
agreement based on this Standard 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 150, Pressure vessels
GB/T 228, Metallic materials -- Tensile testing (GB/T 228-2002, eqv ISO 6892.1998)
GB/T 9113 (all parts), Integral steel pipe flanges
GB/T 12220, Industrial valves -- Marking (GB/T 12220-1989, idt ISO 5209.1977)
GB/T 12221, Metal valves -- Face to face, end to end, center to face and center to
end dimensions (GB/T 12221-2005, ISO 5752.1982, MOD)
GB/T 12223, Part-turn valve actuator attachments (GB/T 12223-2005, ISO
5211.1991, MOD)
GB/T 12224, General requirements for industrial steel valves (GB/T 12224-2005,
3 Structural form
3.1 The basic structure and main parts names of the butterfly valve are shown in Figures
1 and 2.
4 Technical requirements
4.1 Parameters
4.2 Butterfly valve performance
4.2.1 Shell strength
There shall be no structural damage to the butterfly valve after the shell strength test.
No visible leakage is allowed through the valve housing wall and any fixed valve body
connections. If the test medium is a liquid, there shall be no visible droplets or surface
moisture. If the test medium is air or other gas, there shall be no bubbles leaking out.
4.3 Use of butterfly valves
4.3.1 Butterfly valves shall be capable of flow regulation.
4.3.2 Butterfly valves with specified medium flow directions shall be installed and used
in the direction indicated by the flow direction.
4.3.3 Butterfly valves shall not be installed in free-draining pipelines.
4.4 Valve body
4.4.1 The structural length of the butterfly valve shall comply with the provisions of
4.4.7 The minimum diameter of the valve seat flow passage shall not be less than the
requirements in Table 2.
Table 2 -- Minimum size of valve seat flow passage
4.4.8 The connection between the valve body sealing ring (valve seat) and the valve
body shall ensure that the valve will not loosen or leak during use.
4.4.9 When the valve body material is HT200, the nominal size shall not be larger than
DN2000, and the minimum wall thickness of the valve body shall be as specified in
Table 3.The valve body is made of other materials, and its minimum wall thickness can
be calculated by referring to Annex A.
4.5 Butterfly plate
4.5.1 The guide surface of the butterfly plate is not to hinder the flow of the medium.
4.5.2 The butterfly plate shall be guaranteed not to deform or be damaged under 1.5
times the maximum allowable operating pressure difference.
4.5.3 The connection strength between the butterfly plate and the valve stem shall be
designed to effectively transmit the valve stem torque. The connection method between
the butterfly plate and the valve stem shall ensure that no loosening occurs under normal
operating conditions.
4.6 Valve stem
4.7 Stem bearing
4.7.1 For butterfly valves with a nominal size of not less than DN350, bearings of
appropriate materials shall be selected to withstand radial thrust.
4.7.2 During the testing and use of butterfly valves, the bearings shall be able to
withstand the maximum load transmitted by the valve stem.
4.7.3 Butterfly valves with axial force shall use appropriate bearings to withstand the
axial thrust. It is not allowed to use spring retaining rings as thrust.
4.8 Stem seal
5 Materials
5.1 The pressure-receiving parts of butterfly valves whose nominal pressure is greater
than PN10 and whose nominal size is greater than DN1000 shall not be made of gray
cast iron.
5.7 The filler can be made of rubber "O"-shaped rings, "V"-shaped
polytetrafluoroethylene, molded flexible graphite and other materials; or according to
the requirements of the ordering contract.
5.8 The bracket can be made of the same material as the valve body or a material with
higher performance than the valve body.
5.9 The materials of other parts can be in accordance with JB/T 5300 or the
requirements of the ordering contract.
5.10 For butterfly valves used in drinking water, food, medicine and other fields, all
materials in contact with the medium shall meet the relevant requirements for hygienic
performance.
6 Test methods
6.1 Shell test
Carry out in accordance with the provisions of GB/T 13927.
6.2 No-load operation test
The drive is mounted directly on the valve. Use the designed drive device to open and
close the butterfly valve three times from fully closed to fully open to fully closed again.
Check whether the butterfly valve is operating normally.
6.6 Measurement of valve stem hardness
Use a hardness tester to measure at both ends of the valve stem. Take the average of
three measurement points for each measurement.
6.7 Analysis of material composition
Take a sample from the body of the valve body. Drill cutting sampling shall be carried
out at 6.5 mm below the surface.
6.8 Mechanical properties of valve body material
Use test rods with the same furnace number and batch of heat treatment as the valve
body to perform the test according to the method specified in GB/T 228.
7 Inspection rules
7.1 Inspection items, technical requirements and inspection methods are as specified in
Table 4.
7.2 Exit-factory test
Butterfly valves must undergo exit-factory inspection and testing one by one. Only after
passing the inspection can it leave the factory.
7.3 Type inspection
7.3.1 In any of the following situations, 1~2 valves shall be provided for type testing.
After passing the test, batch production can be carried out.
7.4 Sampling method
8 Marking
8.1 Mark contents
Butterfly valves shall be marked according to the provisions of GB/T 12220 and JB/T
106, and shall comply with the provisions of 8.2 and 8.3.
8.2 Marking on the valve body
The valve body must be marked with the following permanent markings.
8.3 Mark on nameplate
The nameplate of the gate valve shall have the following content.
9 Painting and storage
9.1 Except for butterfly valves made of austenitic stainless steel, the outer surface of
butterfly valves made of other materials can be painted according to the provisions of
JB/T 106 or according to the color required by the ordering contract.
9.2 Covers made of wood, wood composites, plastic or metal materials shall be used to
protect the ports of the butterfly valve connecting pipes. The cover shall be shaped with
lug edges.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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