ISO 17292:2015 石油、石油化学および関連産業向けの金属製ボールバルブ | ページ 6

3.1

DN

alphanumeric designation of size common for components used in a piping system, used for reference purposes, comprising the letters DN followed by a dimensionless number indirectly related to the physical size of the bore or outside diameter of the end connection as appropriate

Note 1 to entry: The dimensionless number following DN does not represent a measurable value and is not used for calculation purposes except where specified in this International Standard. Prefix DN usage is applicable to steel valves bearing PN designations.

3.2

nominal pipe size

NPS

alphanumeric designation of size common for components used in a piping system, used for reference purposes, comprising the letters NPS followed by a dimensionless number indirectly related to the physical size of the bore or outside diameter of the end connection as appropriate

Note 1 to entry: The dimensionless number may be used as a valve size identifier without the prefix NPS. The dimensionless size identification number does not represent a measurable value and is not used for calculation purposes except where specified in this International Standard. Prefix NPS usage is applicable to steel valves bearing Class designations.

3.3

PN

dimensionless alphanumeric designation used to define a maximum pressure/temperature rating applicable to the valve pressure containing shell comprising the letters PN followed by a dimensionless whole number

Note 1 to entry: The number following the letters PN does not represent a measurable value and is not used for calculation purposes except where specified in this International Standard.

3.4

Class

dimensionless alphanumeric designation used in ASME standards to define a maximum pressure/temperature rating applicable to the valve pressure containing shell comprising the letters Class followed by a dimensionless whole number

Note 1 to entry: The number following the letters Class does not represent a measurable value and is not used for calculation purposes except where specified in this International Standard.

3.5

anti-static design

design that provides for electrical continuity between the body, ball, and stem of the valve

3.6

polytetrafluoroethylene

PTFE

synthetic fluoropolymer of tetrafluoroethylene which is a high-molecular-weight thermoplastic consisting wholly of carbon and fluorine

3.7

reinforced PTFE

PTFE (3.6) compounded with filler or reinforcing materials such as glass fibre, carbon, metal powders, and graphite uniformly dispersed within to achieve greater strength, increase creep resistance, lower wear rate, and higher pressure-temperature rating

3.8

modified PTFE

PTFE (3.6) compounded with a small percentage of perfluoropropyl vinyl ether (PPVE) to reduce melt viscosity during processing enabling better fusion of the PTFE particles during sintering thereby increasing creep resistance

3.9

reinforce modified PTFE

modified PTFE (3.8) compounded with filler or reinforcing materials such as glass fibre, carbon, metal powders, and graphite uniformly dispersed within to achieve greater strength, increase creep resistance, lower wear rate, and higher pressure-temperature rating