GB/T 9126.2-2023Non-metallic flat gaskets for pipe flanges - Part 2: Class designated (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part

1.Structure and Drafting Rules of Standardization Documents" Drafting. This document is part 2 of GB/T 9126 "Non-metallic flat gaskets for pipe flanges". GB/T 9126 has released the following parts.

---Part 1: PN series;

2.Class Series. This document partially replaces GB/T 9126-2008 "Dimensions of non-metallic flat gaskets for pipe flanges" and GB/T 9129-2003 "Pipe flanges" Technical Conditions for Non-metallic Flat Gaskets", compared with GB/T 9126-2008 and GB/T 9129-2003, except for structural adjustment and editing In addition to the modifications, the main technical changes are as follows:

a) The asbestos rubber sheet gasket material is deleted (see

3.1 of GB/T 9129-2003);

b) Added gasket type (see Chapter 5);

c) Added that flat ring gaskets can be equipped with metal inner edges and related regulations (see Chapter 5, 6.3);

d) Added modified polytetrafluoroethylene and expanded polytetrafluoroethylene materials and requirements (see

e) Added gasket dimensions for DN550 (NPS22) flat flange, raised surface flange and concave and convex surface flange (see Table 1~Table 3);

f) The gasket (inner diameter) size and gasket thickness have been modified (see Table 1~Table 4, Table 5~Table 8 of GB/T 9126-2008);

g) Delete the PN series gasket dimensions (see Table 1~Table 4 of GB/T 9126-2008);

h) Changed the gasket size limit deviation (see Table 5 and Table 6, Table 5 and Table 6 of GB/T 9129-2003);

i) Added storage period and related regulations for rubber and asbestos-free fiber gaskets (see 11.2.2). Please note that some content in this document may be subject to patents. The publisher of this document assumes no responsibility for identifying patents. This document is proposed by China Machinery Industry Federation. This document is under the jurisdiction of the National Technical Committee on Standardization of Pipe Accessories (SAC/TC237). This document was drafted by: Ningbo Tiansheng Seals Co., Ltd., Zhongji Productivity Promotion Center Co., Ltd., Zhejiang Cathay Xiaoxing Sealing Materials Materials Co., Ltd., Cixi Hengli Sealing Materials Co., Ltd., Guangzhou Dongshan Southern Seals Co., Ltd., PetroChina East China Design Institute Ltd. The main drafters of this document. Qiu Kuanheng, Feng Feng, Wu Yimin, Li Xinggen, Wu Shuji, Xu Shaohuan, Liu Hongfu, Luo Wenjun. The previous versions of this document and the documents it replaces are as follows:

1 Scope

GB/T 9126.2-2023 is Part 2 of the Chinese series on non-metallic flat gaskets for pipe flanges, covering the Class designated series used with ASME-pattern flanges. Separating the two series is not bureaucratic: the bolt circles and raised face dimensions differ, and a gasket cut to the wrong series either overhangs into the bore or sits under the bolts, and in both cases the joint leaks. The standard sets the materials, the requirements on appearance, dimensions and dimensional tolerances, the inspection methods, the inspection rules with their sampling and acceptance provisions, the marking, and the packaging, storage and transport provisions, with an informative annex on the stress relaxation of gaskets in the commonly used materials. It took effect on 1 April 2024.

This document specifies the types, materials, requirements, test methods, inspection rules, markings and logo, packaging, storage and transportation. This document applies to non-metallic flat gaskets with nominal pressures of Class150 and Class300.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

GB/T 5574 Industrial rubber sheet

GB/T 12385-2008 Gasket sealing performance test method for pipe flanges

GB/T 12621-2008 Gasket stress relaxation test method for pipe flanges

GB/T 12622-2008 Test method for compression rate and rebound rate of gaskets for pipe flanges JC/T 2052 Roll-pressed asbestos-free fiber gasket material QB/T 5257 Polytetrafluoroethylene (PTFE) sheet

3 Terms and definitions

There are no terms or definitions to be defined in this document.

4 Symbols and abbreviations

The following symbols and abbreviations apply to this document. b. Inner wrapping width, unit is millimeter (mm) D. Gasket outer diameter, unit is millimeter (mm) d. Gasket inner diameter, unit is millimeter (mm) K. Bolt hole center circle diameter, unit is millimeter (mm) L. Bolt hole diameter, unit is millimeter (mm) n. Number of bolt holes, unit is units T. gasket thickness, unit is millimeter (mm) CR. Chloroprene Rubber (ChloropreneRubber) FKM. Fluororubber (Fluororubber) NAS. Non-asbestos fiber (Non-asbestos)