This standard specifies the structural types, product models, requirements, inspection and test methods, inspection rules, marking, packaging, transport and storage all regarding the slow closure butterfly check valve (hereinafter referred to as the check valve).
This standard is applicable to the check valve of DN300 ~ DN2000 (with nominal pressure not greater than PN10 for those of DN1000 or above and PN16 for those of DN1000 or below), with water or other liquids of which physical and chemical properties are similar to those of water as the medium, which is installed onto pump outlet pipeline to prevent medium backflow and destructive water hammer caused by abnormal pumping off.
2 Normative References
The following standards contain provisions which, through reference in this standard, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding corrigendum), or revisions of, any of these publications do not apply. However, all parties coming to an agreement based on this standard are encouraged to investigate whether the most recent editions of the standards apply. For undated references, the latest editions of the normative documents referred to apply.
GB/T 196 General Purpose Metric Screw Threads - Basic Dimensions
GB/T 197 General Purpose Metric Screw Threads - Tolerances
GB/T 1047 Pipework Components - Definition and Selection of DN (Nominal Size)
GB/T 1048 Pipework Components - Definition and Selection of PN (Nominal Pressure)
GB/T 6739-2006 Paints and Varnishes - Determination of Film Hardness by Pencil Test
GB/T 8923-1988 Rust Grades and Preparation Grades of Steel Surfaces Before Application of Paints and Related Products
GB/T 9286-1998 Paints and Varnishes--Cross Cut Test for Films
GB/T 9969.1 General Principles for Preparation of Instructions for Use of Industrial Products
GB/T 12220 General Purpose Industrial Valves - Marking
GB/T 12221-2005 Metal Valves - Face to Face, End to End, Center to Face and Center to End Dimensions
