GB/T 12221-2005 in English

《GB/T 12221-2005金属阀门 结构长度》由TC188（全国阀门标准化技术委员会）归口，主管部门为中国机械工业联合会
本标准规定了法兰连接阀门的结构长度、焊接端阀门的结构长度、对夹连接阀门的结构长度、内螺纹连接阀门结构长度、外螺纹连接阀门结构长度，及其结构尺寸的极限偏差。本标准适用于公称压力PN≤42.0 MPa，公称通径DN3mm～DN4000mm的闸阀、截止阀、球阀、蝶阀、旋塞阀、隔膜阀、止回阀等的结构长度。

1 Scope

This Standard specifies the basic series of face-to-face, centre-to-face, end-to-end and centre-to-end dimensions of flanged joint valves, welded end valves, wafer type connection valves, female thread connection valves, male thread connection valves, and the permissible variations of structural dimensions.
This standard is applicable to the face-to-face, centre-to-face, end-to-end and centre-to-end dimensions of gate valves, stop valves, ball valves, butterfly valves, plug valves, diaphragm valves and check valves with nominal pressure (PN) ≤ 42.0 MPa and nominal diameter of DN 3 mm ~ DN 4 000 mm.

2 Normative References

The following normative documents contain provisions which, through reference in this text, constitute provisions of this Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below.
GB/T 1047 Pipework Components — Definition and Selection of DN (Nominal Size) (GB/T 1047-2005, ISO 6708:1995, MOD)
GB/T 1048 Pipework Components — Definition and Selection of PN (GB/T 1048-2005, ISO 7268:1996, MOD)

3 Definitions