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Similar standardsGB/T 12241-2021: Safety valves - General requirements---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/GBT12241-2021NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA ICS 13.240 J 16 Replacing GB/T 12241-2005 Safety valves - General requirements (ISO 4126-1.2013, Safety devices for protection against excessive pressure - Part 1. Safety valves, MOD) Issued on. MARCH 09, 2021 Implemented on. OCTOBER 01, 2021 Issued by. State Administration for Market Regulation; Standardization Administration of the People's Republic of China. Table of ContentsForeword... 3 1 Scope... 6 2 Normative references... 6 3 Terms and definitions... 7 4 Symbols and units... 9 5 Design... 10 5.1 General... 10 5.2 End connection... 11 5.3 Minimum requirements for springs... 12 5.4 Pressure-temperature rated values... 15 6 Exit-factory tests... 15 6.1 Purpose... 15 6.2 General... 16 6.3 Hydraulic test... 16 6.4 Air pressure test... 17 6.5 Adjustment of set pressure or cold differential test pressure... 18 6.6 Seal test... 18 7 Type test... 18 7.1 General... 18 7.2 Action performance test... 20 7.3 Discharge capacity performance test... 21 7.4 Determination of coefficient of discharge... 23 7.5 Certified coefficient of discharge... 23 8 Determination of discharge capacity performance of safety valve... 24 9 Determination of safety valve size... 24 10 Marks and lead seals... 24 10.1 Marks... 24 10.2 Lead seal of safety valve... 25 Bibliography... 26ForewordThis Standard was drafted in accordance with the rules given in GB/T 1.1-2009. This Standard replaces GB/T 12241-2005 “Safety valves - General requirements”. Compared with GB/T 12241-2005, in addition to the editorial modifications, the main technical changes are as follows. a) Changed applicable flow diameter range (see Chapter 1 of this Edition, Chapter 1 of Edition 2005); b) Deleted the terms and definitions for "pilot-operated safety valve, equivalent discharge capacity, mechanical characteristics"; Added the terms and definitions for “maximum allowable pressure, back pressure, balanced bellows, coefficient of discharge” (see Chapter 3 of this Edition, Chapter 3 of Edition 2005); c) Added symbols and unit descriptions (see Chapter 4 of this Edition); d) Added the requirements for lift limit mechanism (see 5.1.3 of this Edition); e) Added the requirements for "sliding mating surfaces, valve seats and discs, sealing elements, and lifting mechanisms" (see 5.1.8~5.1.11 of this Edition); f) Deleted the requirements for nominal diameter and nominal pressure (see 4.1.2 of Edition 2005); g) Changed the end connection involving requirements (see 5.2.2 of this Edition, 4.1.3.2 of Edition 2005); h) Changed the minimum requirements for springs and divided into "minimum requirements for helical compression springs" and "minimum requirements for disc springs" (see 5.3 of this Edition, 4.1.4 of Edition 2005); i) Deleted the safety valve material requirements (see 4.1.5 of Edition 2005); j) Changed the general requirements of exit-factory test (see 6.2 of this Edition, 5.1.2 of Edition 2005); k) Changed the adjustment requirements for cold differential test pressure (see 6.5 of this Edition, 5.1.5 of Edition 2005); l) Changed the requirements for operating performance and discharge capacity test (see Chapter 7 of this Edition, 5.2 of Edition 2005); m) Deleted the requirements of "quality assurance system, installation of safety valves, adjustment, maintenance and repair of safety valves" (see Chapter 9~11 of Edition 2005). This Standard uses redrafting method to modify and adopt ISO 4126-1.2013 (including Amendment in 2016) “Safety devices for protection against excessive pressure - Part 1. Safety valves”. Compared with ISO 4126-1.2013 (including Amendment in 2016), there are some structural adjustments in this Standard. The specific chapter numbers are as follows. a) The content of 7.2.4 in ISO4126-1.2013 is 7.2.3 in this Standard. b) The note in Figure 1 of ISO 4126-1.2013 is adjusted to 5.2.2 of this Standard. There are technical differences between this Standard and ISO 4126-1.2013 (including Amendment in 2016). These differences and their reasons are as follows. a) Regarding normative references, this Standard has made adjustments with technical differences to adapt to China's technical conditions and meet the needs of China's application. The adjustment is concentrated in Chapter 2 "Normative references". The specific adjustments are as follows. • Use GB/T 36588 that is modified by adopting the international standard to replace ISO 4126-7; • Added GB/T 1239.2, GB/T 7306 (all parts), GB/T 9124 (all parts), GB/T 12224, GB/T 12716, GB/T 15530.1, GB/T 15530.8, GB/T 17241.6, GB/T 17241.7, GB/T 23934, JB/T 2768, JB/T 2769 appear in the text. b) Deleted the terms and definitions of "safety valve with power assist" and "safety valve with supplementary load" not used in the text. c) Added the requirements of 5.2.1 end connection type to meet the needs of China in practical applications. d) Added specific requirements for pressure-temperature ratings in 5.4 to meet the needs of China in practical applications. e) Deleted the test equipment requirements in 7.2.3 of ISO 4126-1.2013, because the corresponding provisions have been made in GB/T 12242. This Standard made the following editorial modifications. a) Changed the standard name from “Safety devices for protection against excessive pressure - Part 1.Safety valves” to “Safety valves - General requirements” that is unified with GB/T 12241-2005. b) Added bibliography to facilitate China's needs in practical applications. This Standard was proposed by China Machinery Industry Federation. This Standard shall be under the jurisdiction of National Technical Committee on Safety Pressure Relief Device of Standardization Administration of China (SAC/TC 503). The drafting organizations of this Standard. Shanghai Kite Valve Manufacturing Co., Ltd., Hefei General Machinery Research Institute Co., Ltd., Shanghai Valve Factory Co., Ltd., Yongyi Valve Group Co., Ltd., Tianzheng Valve Co., Ltd., Yangzhong Valve Factory Co., Ltd., Beijing Aerospace Petrochemical Technology Equipment Engineering Co., Ltd., Wuhan Boiler Group Valve Co., Ltd., Chengde High and Medium Pressure Valves and Fittings Group Co., Ltd., Jiangsu Suyan Valve Machinery Co., Ltd., Shanghai Hugong Valve Factory (Group) Co., Ltd., Henan Gaoshan Valve Co., Ltd., Zhejiang Chaochao Safety Valve Manufacturing Co., Ltd. Company, Xuzhou Bafang Safety Equipment Co., Ltd., Wujiang Dongwu Machinery Co., Ltd., Keke Group Co., Ltd., Wuhan Huake Energy Environmental Technology Co., Ltd., Kairuite Valve Co., Ltd., Lianggong Valve Group Co., Ltd. Main drafters of this Standard. Zhao Nanping, Wang Deping, Wang Xiaojun, Wang Qiulin, Gan Aigen, Zhang Junce, Chen Jinlong, Wang Xuebin, Zhang Na, Zhan Yongfu, Han Zhenghai, Yang Xiongjun, Yang Quanqing, Ding Chaochao, Shu Yuan, Zi Xiaofeng, Wang Haizhuang, Hu Liangyin, Zhang Chuanhu, Peng Yu Lin, Jiang Zhendong. Versions of standard substituted by this Standard are. - GB/T 12241-1989, GB/T 12241-2005. Safety valves - General requirements1 ScopeThis Standard specifies the terms and definitions of safety valve, design, exit-factory test, type test, determination of safety valve discharge capacity performance, determination of safety valve size, marks and lead seals.2 Normative referencesThe 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.3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply. the pressure increments above the set pressure of the safety valve4 Symbols and unitsSee Table 1 for a description of symbols and units.5 DesignThe spring manufacturer shall provide a quality assurance certificate for the spring, to indicate that the spring is made of the specified material and has been processed and tested according to the technical requirements of the safety valve manufacturer. The pressure-temperature rating of the steel safety valve is in accordance with the provisions of GB/T 12224.6 Exit-factory testsFor hydraulic tests of safety valve shells that meet the following requirements, equivalent tests (such as design verification tests combined with statistical sampling) are allowed to be used instead.7 Type testThe purpose of the test is to determine, under specific test conditions, at least the following characteristics of the valve before opening, during discharge and when reseated.8 Determination of discharge capacity performance of safety valveThe determination of the discharge capacity performance of the safety valve is in accordance with the provisions of GB/T 36588.9 Determination of safety valve sizeThe size of the safety valve is determined according to the provisions of GB/T 36588. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al. |
