Specification for minimal thickness of the shell of valves
1 Scope
This standard specifies the requirements for thickness of iron and steel valves such as ball valves, butterfly valves, gate valves, globe valves, check valves, plug valves and diaphragm valves.
The parameter range of valves applicable to this standard is as follows:
a) Steel valves with nominal pressure of PN 10 to PN 760, nominal pressure of PN 760 is only applicable to welded end valves;
b) Flange, wafer and butt-welding end steel valves with nominal dimension not greater than DN 1250;
c) Socket welding and threaded end steel valves with nominal dimension not larger than DN 100;
d) Iron valves with nominal pressure of PN 1.0 to PN 25;
e) Iron valves with nominal dimension not greater than DN 3000.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this national standard. For dated references, subsequent amendments (excluding corrections) to, or revisions, of any of these publications do not apply to this standard. 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. For undated references, the latest edition of the normative document referred to applies.
GB/T 12224-2005 General requirements for industrial steel valves (ASTM B16.34a: 1998, NEQ)
GB/T 14976 Seamless stainless steel pipes for fluid transport (GB/T 14976-2002, ASTM A269: 2000, NEQ)
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3 Minimal thickness of steel valve
3.1 General requirements
3.1.1 Determination of minimal thickness by table look-up
The thickness tm of steel valve body shall not be less than that specified in Table 1, except for the end dimensions specified in 3.1.3 to 3.1.6 and 3.1.8, and 6.2 and 6.7 of GB/T 12224-2005.
When using Table 1, the listed intermediate value may be obtained by linear interpolation method.
The thickness of valve body without lining is measured from the inner surface in contact with the fluid. The minimal thickness of the gaskets, insert or bushing is not covered.
3.1.2 Calculation of minimal thickness
The thickness cannot be obtained from Table 1, but may be calculated using Equation (1). The minimal thickness specified in Table 1 is larger than that calculated using Equation (1).
Foreword i
1 Scope
2 Normative references
3 Minimal thickness of steel valve
4 Minimal thickness of iron valve
Annex A (Informative) Relationship between nominal dimension of steel valve and basic inner diameter of valve body end
