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This standard is not equivalent to the national standard of Italy "Threaded Tubular Rivets with Cylindrical Head" (UNI 9201:1988)
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 7512-2006 Valves for liquefied petroleum gas cylinders
The following main changes have been made with respect to GB/T 7512-2006:
——the term of “non-removable" is redefined;
——the model designation of the valve is modified;
——the structural type of the valve without self-closing devices is deleted;
——basic dimensions such as total height, the hand wheel diameter, the neck diameter of the valve, etc., are modified;
——the material designation HPb59-2 for the main parts of valves are added, requirements for mechanical properties and chemical composition of the materials are defined; (see Sub-clause 6.1.1 and Table 3)
——the requirement of stress corrosion resistance for the raw material of the valve body is changed to such requirement for the valve body;
——the pressure resistance of the valve body from is increased from 4 times the nominal working pressure to 5 times the nominal working pressure;
——the specification and dimension of the thread at gas inlet and outlet of the liquid-phase valve are added;
——the opening and closing requirements for the valve in the fully open state are added;
——the requirements for leakage amount of the valve are added, and the airtightness test methods are modified;
——the allowable mounting torque of PZ39.0 thread at gas inlet of the valve is added;
——the requirements and test methods for the temperature resistance of the valve and fire resistance of the hand wheel are added;
——the minimum design service life of the valve is added;
——the requirements for site re-inspection of nonmetal sealing elements are added;
——the number of valves per batch from 20,000 to 10,000 is reduced;
——the marking of the valve and the contents of the product certificate are added.
This standard was proposed by and is under the jurisdiction of the National Technical Committee on Gas Cylinder of Standardization Administration of China (SAC/TC 31).
The previous editions of this standard are as follows:
——GB/T 7512-1987, GB/T 7512-1999 and GB/T 7512-2008
Valves for liquefied petroleum gas cylinders
1 Scope
This standard specifies the terms and definitions, model designation, structural type and basic dimension, technical requirements, examination and test methods, inspection rules, marking, packaging and storage and transportation of valves for liquefied petroleum gas cylinders (hereinafter referred to as “valves”).
This standard is applicable to the valves for liquefied petroleum gas cylinders, at an ambient temperature of -40℃~ +60℃, with a nominal working pressure of not greater than 2.5 MPa, and with a medium in accordance with GB 11174.
This standard is not applicable to valves for liquefied petroleum gas cylinders for vehicles.
Note: The pressure referenced in this standard refers 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 normative document (including any amendments) applies.
GB/T 197 General purpose metric screw threads - Tolerances (GB/T 197-2003, ISO 965-1:1998, MOD)
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature (GB/T 228.1 - 2010, ISO 6892-1: 2009, MOD)
GB/T 1184 Geometrical tolerancing - Geometrical tolerances for features without individual tolerance indications (GB/T 1184-1996, eqv ISO 2768-2:1989)
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 3934 Specification of gauges for general purpose screw threads (GB/T 3934-2003, ISO 1502:1996, MOD)
GB/T 5121.1 Methods for chemical analysis of copper and copper alloys-Part 1: Determination of copper content (GB/T 5121.1-2008, ISO 1554.1976, ISO 1553:1976, MOD)
GB/T 5121.3 Copper and copper alloys-Determination of lead content (GB/T 5121.3-2008, ISO 4749:1984, MOD)
GB/T 5121.9 Methods for chemical analysis of copper and copper alloys-Part 9: Determination of iron content (GB/T 5121.9-2008, ISO 4748:1984, ISO 1812:1976, MOD)
GB/T 8335 Special threads for gas cylinders
GB/T 8336 Special thread gauges for gas cylinders
GB/T 10567.2 Wrought copper and copper alloys - Detection of residual stress - Ammonia test
GB 11174 Liquefied petroleum gas
GB/T 13005 Terminology of gas cylinders
GB/T 15382 General specifications of gas cylinder valves
3 Terms and definitions
For the purpose of this standard, the terms and definitions established in GB/T 13005 as well as the following ones apply.
3.1 non-removable valve
the valve that can be removed only by destroying the pressure parts on the valve, and can't work normally once removed
3.2 the self-closing device
a protective device set at the gas outlet of the valve, that automatically opens the valve once connected to the gas filling device (or pressure regulator) and automatically closes the valve once the gas filling device (or pressure regulator) is removed
4 Model designation
4.1 The code of the valve: it is represented by "YSQ”, i.e., the respective first letters of corresponding Chinese phonetic alphabets of the medium “liquefied petroleum gas”.
4.2 The code of the self-closing device: it is represented by "Z".
4.3 The modification S.N of the valve: it is represented by Arabic number, in the order of the number of modifications.
4.4 The code of thread at gas inlet of the valve: it is represented by capital English letters, "A" for PZ19.2 thread, "B" for PZ27.8 thread, and "C" for PZ39.0 thread.
Note: In order to adapt to the long-term convention of users, the code "B" of PZ27.8 thread can be omitted in the model designation.
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Example:
5 Structural type and basic dimension
5.1 The valve is non-removable in the structural type, and its basic dimension is in accordance with those specified in Figure 1 and Table 1.
5.2 The lift height of the valve shall not be less than the 1/4 of nominal diameter.
5.3 The thread at the gas inlet of the valve has three specifications. Types of threads used on the gas-phase valve are PZ19.2 and PZ27.8. The thread used on the liquid-phase valve is PZ39.0, and its dimension and manufacturing precision shall meet the requirements of GB/T 8335.
5.4 The thread at the gas outlet of the valve has three specifications. The type of gas outlet and connection dimensions are as specified in Table 2, while the thread dimension and manufacturing precision shall be in accordance with those specified in GB/T 197.
5.5 For the valve with PZ19.2 thread at the gas inlet , the diameter of gas inlet in its end part shall be not greater than 9 mm; for the valve with gas inlet thread of PZ27.8, the diameter of gas inlet in its end part shall be not greater than 14 mm. The end part of liquid-phase valve shall have liquid-phase pipe, whose inner diameter shall be greater than the diameter of gas inlet of the valve; and its connecting thread is M16×1.5.
5.6 Where relevant laws, regulations and codes of the State are met, as needed by the user, filling limit device or residual combustion device may be added at the gas inlet of the valve.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Model designation
5 Structural type and basic dimension
6 Technical requirements
6.1 Material Requirements
6.1.1 Metallic materials
6.1.2 Material of nonmetal sealing elements
6.2 Process requirements
6.3 Property requirements
6.3.1 Opening and closing property
6.3.2 Airtightness
6.3.3 Vibration resistance
6.3.4 Temperature resistance
6.3.5 Durability
6.3.6 Pressure resistance of valve body
6.3.7 Stress corrosion resistance of valve body
6.3.8 Installation
6.3.9 Fire resistance of hand wheel
6.4 Minimum service life
7 Examination and test method
7.1 General notes of test
7.2 Mechanical property test method and chemical composition analysis method of metallic material of valve body.
7.3 Material property test of nonmetal sealing elements
7.3.2 Low-temperature resistance test of non-rubber seal
7.4 Appearance inspection
7.5 Basic dimensions of the valve and inspection of thread at gas inlet and outlet
7.6 Mass inspection
7.7 Test of opening and closing
7.8 Airtightness test
7.9 Vibration resistance test
7.10 Temperature resistance test
7.11 Durability test
7.12 Pressure test of valve body
7.13 Stress corrosion resistance test of valve body
7.14 Installation test
7.15 Fire resistance test of hand wheel
8 Inspection rules
8.1 Material inspection
8.2 End-of-manufacturing inspection
8.3 Type test
8.4 Inspection items
9 Marking, packaging and storage
9.1 Marking
9.2 Packaging
9.3 Storage and transportation
