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GB/T 37842-2019 English PDF (GBT37842-2019)

GB/T 37842-2019 English PDF (GBT37842-2019)

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GB/T 37842-2019: Ball valves of thermoplastics materials

This standard specifies the terms, definitions and symbols, materials, design, requirements, test methods, inspection rules, signs, packaging, transportation and storage of ball valves of thermoplastics materials.
GB/T 37842-2019
GB
NATIONAL STANDARD OF THE
PEOPLE REPUBLIC OF CHINA
ICS 83.140.30
G 33
Ball valves of thermoplastics materials
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(ISO 16135:2006, Industrial valves - Ball valves of thermoplastics materials, MOD)
ISSUED ON: AUGUST 30, 2019
IMPLEMENTED ON: MARCH 01, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative references ... 6
3 Terms, definitions and symbols ... 7
4 Materials ... 12
5 Design ... 13
6 Requirements ... 16
7 Test method ... 20
8 Inspection rules ... 21
9 Marking, packaging, transportation and storage ... 23
Appendix A (Informative) Type selection of multi-way ball valve ... 25 Appendix B (Informative) Comparison between nominal outer diameter dn and nominal diameter DN ... 30
Appendix C (Informative) Purchasing Information ... 31
References ... 33
Ball valves of thermoplastics materials
1 Scope
This standard specifies the terms, definitions and symbols, materials, design, requirements, test methods, inspection rules, signs, packaging, transportation and storage of ball valves of thermoplastics materials (hereinafter referred to as ball valves).
According to the different materials of ball valves, this standard has a temperature range of -40 ??C ~ +120 ??C.
The nominal outer diameter range is dn16 mm ~ dn180 mm.
The nominal pressure range is PN 0.6 MPa ~ PN 2.5 MPa.
The range of pipe series is S2 ~ S12.5.
Note: It is the responsibility of the purchaser to select this product appropriately according to its specific application needs and in conjunction with relevant regulations, standards or specifications.
2 Normative references
The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this standard.
GB/T 2828.1-2012 Sampling procedures for inspection by attributes -Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection (AQL) (ISO 2859-1:1999, IDT)
GB/T 2918-2018 Plastics - Standard atmospheres for conditioning and
testing (ISO 291:2008, MOD)
GB/T 7306.1-2000 Pipe threads with 55 degree thread angle where
pressure-tight joints are made on the threads - Part 1: Parallel internal and taper external threads (eqv ISO 7-1:1994)
GB/T 7306.2-2000 Pipe threads with 55 degree thread angle where
pressure-tight joints are made on the threads - Part 2: Taper internal and external threads (eqv ISO 7-1:1994)
GB/T 8806-2008 Plastics piping systems - Plastics components -
Determination of dimensions (ISO 3126:2005, IDT)
GB/T 12223-2005 Part-turn valve actuator attachments (ISO 5211:2001,
MOD)
GB/T 17219 Safety evaluation standard for drinking water delivery and
distribution equipment and protective materials
GB/T 19278-2018 General terms and their definitions of thermoplastic pipes, fittings and valves
GB/T 21300-2007 Plastics pipes and fittings - Determination of opacity (ISO 7686:2005, IDT)
GB/T 27726-2011 Thermoplastics valves - Pressure test methods and
requirements (ISO 9393-1:2004, MOD)
GB/T 28494-2012 Globe valves of thermoplastics materials (ISO
21787:2006, MOD)
GB/T 30832-2014 Valves - Test method of flow coefficient and flow
resistance coefficient
ISO 10931:2005 Plastics piping systems for industrial applications - Poly (vinylidene fluoride) (PVDF) - Specifications for components and the system ISO 15493:2003 Plastics piping systems for industrial applications -
Acrylonitrile-butadiene-styrene (ABS), unplasticized poly (vinyl chloride) (PVC-U) and chlorinated poly (vinyl chloride) (PVC-C) -Specifications for components and the system - Metric series
ISO 15494:2015 Plastics piping systems for industrial applications -
Polybutene (PB), polyethylene (PE), polyethylene of raised temperature
resistance (PE-RT), crosslinked polyethylene(PE-X), polypropylene (PP) - Metric series for specifications for components and the system
3 Terms, definitions and symbols
The terms and definitions as defined in GB/T 19278-2018 as well as the
following terms and definitions apply to this document.
3.1 Terms and definitions related to geometric dimensions
3.1.1
Nominal size
S: Pipe series
4 Materials
4.1 Shell material
4.1.1 The polyvinylidene fluoride (PVDF), acrylonitrile-butadiene-styrene (ABS), unplasticized polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride, bonnets/bonnets (PVC-C), polybutene (PB), polyethylene (PE), heat-resistant polyethylene (PE-RT), cross-linked polyethylene (PEX), polypropylene (PP) used in the production of valve body and bonnet shall comply with the
requirements of ISO 10931:2005, ISO 15493:2003, ISO 15494:2015.
4.1.2 For the materials selected for the valve body and bonnet, the raw material supplier shall provide a raw material creep failure curve report that meets the requirements of the predicted strength reference curve.
4.1.3 When selecting polyphenylene ether (PPO/PPE), polyphenylsulfone
(PPSU), polyamide (PA) or other materials, the supplier shall provide the raw material creep failure curve report and temperature derating factor fr. 4.2 Materials of other components of ball valve
The selection of materials for other components such as seals, stems, balls shall ensure that the performance of the ball valve meets the requirements specified in Chapter 6; these materials shall not adversely affect the
performance of the ball valve.
4.3 Pressure-temperature reduction
4.3.1 The maximum allowable operating pressure MOP of the ball valve is related to the operating temperature, the characteristics of the valve body material, the structural design. The maximum allowable operating pressure MOP of the ball valve shall be determined by the derating factor fr, which can be calculated according to formula (2):
Where:
MOP - The maximum allowable operating pressure, in megapascals (MPa);
fr - The derating factor;
PN - Nominal pressure, in megapascals (MPa).
4.3.2 When the designed service life is 25 years and the delivered fluid has no a) Two-way ball valve:
- Two-way ball valve, which is suitable for two-way fluid flow and isolation; - One-way ball valve; the flow direction shall be marked with an arrow on the outside of the shell.
b) Multi-way ball valve:
- Suitable for commutation/allocation of fluids; it is also suitable for isolating one or more channels of it.
c) Ball:
- The ball is driven by the stem to rotate; it is positioned by friction at any position at the end or in the middle; the fluid pressure cannot rotate it. d) Stem:
- It is fixed in the valve body; the seal between it and the valve body shall meet the requirements of 6.7;
- It is sealed by the self-sealing elements;
- Design or mark the direction of the ball hole on the visible end of the stem (two-way ball valve), or the way the fluid passes through the ball (multi-way ball valve);
- The design of the connection between the stem and the ball shall ensure that the position of the above-mentioned marks or identifications cannot be changed when re-assembled after disassembly.
5.1.3 The minimum flow area shall be designed according to the requirements of Table 3, Table 4, Table 5 in 6.3.2.
5.1.4 Ball valves should use self-sealing elements or packing to seal the valve body.
5.2 Connection
5.2.1 There are the following ways to connect the ball valve to the pipeline: a) Bonding connection;
b) Electrofusion connection;
c) Hot-melt connection;
d) Socket elastic sealing ring connection;
6.3.2.4 Refer to Appendix B for the comparison between the nominal outer diameter dn and the nominal diameter DN.
6.4 Shell strength
The shell strength of the ball valve shall meet the requirements of A.2 in GB/T 27726-2011.
6.5 Overall strength of ball valve
The overall strength of the ball valve shall meet the requirements of A.3 in GB/T 27726-2011.
6.6 Flow capacity
The manufacturer shall provide the nominal value of the flow coefficient and flow resistance coefficient of the ball valve. The measured value of the flow coefficient shall not be less than 90% of the given value; the measured value of the flow resistance coefficient shall not be greater than 110% of the given value. 6.7 Tightness of seat and valve body
The tightness of the seat and valve body shall meet the requirements of A.4 in GB/T 27726-2011.
6.8 Operating torque
When the pressure difference is equal to the nominal pressure PN, the torque value of the ball valve fully opened or fully closed shall not be greater than the nominal value given by the manufacturer.
6.9 Fatigue strength
6.9.1 The ball valve shall not leak during the test.
6.9.2 After the test, the sealing performance of the ball valve shall meet the requirements of A.4 in GB/T 27726-2011.
6.9.3 All functions of the ball valve can still be used normally after the test. 6.9.4 The number of cycles of the ball valve with dn < 63 mm shall be no less than 15000; the number of cycles of the ball valve with dn ??? 63 mm shall be no less than 5000.
6.10 Light transmittance
The light transmittance of the ball valve shall be ??? 0.2%.
6.11 Hygiene requirements
valve according to Appendix C of GB/T 28494-2012; meanwhile it shall meet the following requirements:
a) At the input end of the ball valve, use water at MOP pressure and 15 ??C ~ 30 ??C as the test medium;
b) When the ball valve is fully opened, make the water flow rate reach (1 ?? 0.2) m/s;
c) When the ball valve is completely closed, the time for the pressure at the output end to be equal to atmospheric pressure shall not be less than 5 s; d) The stem shall not be affected by radial force during the test;
e) Repeat steps b) and c).
7.10 Light transmittance
Carry out test according to GB/T 21300-2007. The specimen is taken from a pipe made of the same material as the ball valve shell.
7.11 Hygiene requirements
Carry out test according to GB/T 17219.
8 Inspection rules
8.1 Inspection classification
Inspection is divided into exit-factory inspection and type inspection. 8.2 Group-batch and grouping
8.2.1 Group-batch
Ball valves of the same specification produced continuously by the same material, the same structure, the same assembly process are regarded as a batch. Ball valves with dn < 32 mm specifications do not exceed 30000 pcs per batch; ball valves with 32 mm ??? dn ??? 63 mm specifications do not exceed 10000 pcs per batch; ball valves with dn > 63 mm specifications do not exceed 5000 pcs per batch. If 7 days of production is still less than the above-mentioned quantity, then the output of 7 days will be used as a batch.
8.2.2 Grouping
Group the ball valves by size according to Table 6.
If there is one of the following conditions, type inspection shall also be carried out:
a) After formal production, if there are major changes in molds, materials, processes, which may affect product performance;
b) When the production has been stopped for more than one year for any
reason and then resumed;
c) When there is a big difference between the exit-factory inspection result and the last type inspection result.
8.5 Judgment rules
Appearance, color and size shall be judged according to Table 7. If there is one non-conformity in the hygiene requirements of the ball valve used to transport drinking water, it is judged as an unqualified batch (or product). When one of the other requirements fails to meet the requirements, it shall take double quantity of sample randomly for re-inspection. If it is still unqualified, it will be judged as an unqualified batch (or product).
9 Marking, packaging, transportation and storage
9.1 Markings
9.1.1 The following permanent marks shall be applied to the product:
a) Trademark;
b) Name or abbreviation of shell material;
c) Product specifications: Indicate the nominal outer diameter dn;
d) Ball valves with flanged connection ends, indicating dn and DN;
e) Indication of the nominal pressure PN and pipe series S;
f) Full bore ball valve shall be marked with "QJ";
g) Reduced bore ball valve shall be marked with "SJ".
9.1.2 The product packaging shall have at least the following marks:
a) The name, address, trademark of the manufacturer;
b) Product name and specifications;
c) Production batch number or production date;

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