1 Scope
This standard specifies the technical requirements, inspection, marking, packaging and storage of polyfluortetraethylene gasket.
This standard is applicable to polyfluortetraethylene gasket.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments (excluding amended error) to, or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest editions of these documents are applicable. For undated references, the latest edition of the normative document referred to applies.
GB/T 12385-1990 Standard Test Method for Sealability of Gaskets for Pipe Flanges
GB/T 12622-1990 Test Method for Compressibility and Recovery of Gaskets for Pipe Flanges
3 Technical Requirements
3.1 Performance
3.1.1 The chemical compositions, physical and mechanical performances of polyfluortetraethylene gasket (hereinafter referred to as gasket) materials shall meet the requirements of the relevant material standard.
3.1.2 The test condition and index for compressibility and recovery of gasket shall be in accordance with those specified in Table 1.
3.1.3 The test condition and index for leakage rate of gasket shall be in accordance with those specified in Table 2.
Table 1 Test Condition and Index for Compressibility and Recovery of Gasket
Gasket type Test condition Index
Specification of gasket sample mm Autofrettage pressure, MPa Compressibility (%) Recovery (%)
polyfluortetraethylene gasket DN 40~DN 80, thickness 1.0~3.0 35.0 20 5
≥30
Carbon fiber reinforced polyfluortetraethylene gasket 35.0 13 5
≥40
Elastomeric polyfluortetraethylene gasket 17.25 45 5
≥10
Table 2 Test Condition and Index for Leakage Rate of Gasket
Gasket type Test condition Index
Gasket thickness mm Test medium Autofrettage pressure, MPa Test pressure MPa Leakage rate cm3/s
Polyfluortetraethylene gasket DN40~DN80, thickness 1.0~3.0 99.9 % nitrogen 35.0 4.0 ≤1.0×10-3
Carbon fiber reinforced polyfluortetraethylene gasket 35.0
Expanded polytetrafluoroethylene gasket 17.25
3.2 Appearance
The surface and edge of gasket shall be flat, smooth and free from such defects as crack, lamination, pit, machinery scratch, exogenous impurity, which may affect application.
3.3 Limit deviation of dimension
3.3.1 The limit deviation of gasket dimension for flat pipe flange and raised-face pipe flange shall be in accordance with those specified in Table 3.
Foreword III
1 Scope
2 Normative References
3 Technical Requirements
4 Inspection
5 Marking, Packaging and Storage
Table 1 Test Condition and Index for Compressibility and Recovery of Gasket…………………
Table 2 Test Condition and Index for Leakage Rate of Gasket
Table 3 Limit Deviation of Gasket Dimension for Flat and Raised Face Pipe Flanges
Table 4 Limit Deviation of Gasket Dimension for Male and Female, Tongued and Grooved Pipe Flanges
