ASME Y14.40.8 pdf download

ASME Y14.40.8 pdf download GRAPHICALSYMBOLS FORDIAGRAMS, PART8: VALVES AND DAMPERS
1 sCOPE
This Standard specifies graphical symbols for valvesand dampers in diagrams, including symbols for gen-eral-purpose valves, those used in fluid power systems,and hygienic valves used in the food and pharmaceuticalindustries.
For the fundamental rules of creation and applicationof graphical symbols in diagrams, see ASME Y14.40.0.For an overview of the ASME Y14.40 series, informa-tion on the creation and use of registration numbers foridentifying graphical symbols used in diagrams, rulesfor the presentation and application of these symbols,and examples of their use and application, see ASMEY14.40.1.
REFERENCES
The following references contain provisions that,through reference in this text, constitute provisions ofthis Standard.The latest edition applies.
ASME Y14.40.0,Basic Rules for the Design of GraphicalSymbols for Use in the Technical Documentation ofProducts
ASME Y14.40.1,Graphical Symbols for Diagrams, Part1: General Information and Indexes
ASME Y14.40.2,Graphical Symbols for Diagrams, Part2: Symbols Having General Application
ASME Y14.40.4,Graphical Symbols for Diagrams, Part4: Actuators and Related Devices
Publisher: The American Society of Mechanical Engi-neers (ASME)，Three Park Avenue,New York,NY10016; Order Department: 22 Law Drive,Box 2300,Fairfield, NJ 07007
3TERMS AND DEFINITIONs
For the purposes of this Standard, the following termsand definitions apply.
3.1
safety oalve: valve that automatically, without the assist-ance of any energy other than that of the fluid concerned,discharges a certified quantity of the fluid so as to pre-vent a predetermined safe pressure being exceeded, andthat is designed to reclose and prevent the further flow
of fluid after normal pressure conditions of service have been restored.
3.2 vacuum valve: valve that automatically and without the assistance of any energy other than that of the gas con- cerned, admits gas to a pipeline or tank in order to prevent a predetermined safe underpressure being exceeded.
3.3 control valve: power-operated valve in an industrial- process control system for changing the flow rate of the process fluid.
3.4 restrictor: device that restricts the flow of a fluid, thereby creating a pressure drop.
3.5 restrictor valve: valve in which the inlet and outlet ports are interconnected through a restricted passageway.
NOTE: In a fixed restrictor valve, the cross-sectional area cannot be altered; in an adjustable restrictor valve, the cross-sectional area can be adjusted. 3.6 release valve: valve through which undesired air or steam in a pipe system may be released.
3.7 pressure-reducing valve pressure regulator: valve in which, with varying inlet pressure or outlet flow, the outlet pressure remains substantially constant, but in which the inlet pressure remains higher than the selected outlet pressure.
3.8 pressure-reliefvalve: valve that limits maximum pressure by exhausting fluid when the required pressure is reached.
3.9 exhaust valve: valve in which the outlet is automatically opened to exhaust when the air pressure falls atthe inlet.