Piping, Fittings, and Valves 2024-2025. Questions and Correct Answers. Graded A+, Exams of Engineering

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Piping, Fittings, and Valves 2024-2025.

Questions and Correct Answers. Graded A+

______need leakage from packing but ______do not - ANSShaft seals; valve stems (shafts rotate at high speed, leakage prevents overheating of packing) Actual OD - ANSDesignates pipes over 12" Ball valve - ANSA valve named for the ball-shaped, movable element in the center of the valve; quick opening: 1/4 turn; excellent for flow applications; can be used for throttling Baskets - ANSCan be removed for easy cleaning; 3 types: simplex, duplex, y- strainers Butterfly valve - ANSvalve characterized by their disc-shaped flow-control element, which pivots from its center; more compact than ball or globe valve; 1/ turn to open or close; can throttle; best for low pressure applications; easily equipped for remote operation Check Valve - ANSa valve that automatically closes to prevent the flow of liquid or gas in a reverse direction; prevents return or back flow in pipes Common Schedules - ANSStandard - schedule 40 Extra Strong - Schedule 80 Double Extra Strong - Schedule 160

(Higher the number, thicker the pipe) Compression packing - ANSPacking used to seal shafts, rods, or valve stem seals Design considerations for piping (determine materials, valves, fitting, thickness) - ANSType of fluid transferred Operating pressures and temps Amount of fluid delivered Rate of fluid delivered Drop - ANSVertical pipe line flows downward Duplex - ANSTwo baskets - flow may be diverted to clean off line strainer Flanges - ANSAllow 2 pipes to be mechanically connected together and easily disconnected Gaskets for Flanges - ANSJoints must have gaskets between the faces of the flanges; common type- crush(flexitallic gasket): steel outer ring reinforcing ring and center portion designed to be crushed Gate valve - ANSA shutoff valve closed by lowering a wedge-shaped gate across the passage; parallel gate interposed perpendicular to axis of flow Limitation: Can't throttle- disc will chatter Benefit: loses no pressure; straight flow through

Globe valve - ANSflow of water is cut off by a circular disk that fits against the valve seat. Best for: throttling limitation: large pressure drops Insulation - ANSMinimizes thermal exchange between fluids in pipes and anything outside pipe Lagging - ANSConsists of cloth, tape, or sheet metal and protects the relatively soft insulating material Mechanical compression packing - ANSBenefits: Easy to install Little maintenance Reliable Leaks occur if: Valve stem is bent, scored or rusty Packing gland is crooked Stuffing box scored or nicked Gland not aligned with shaft Gland nuts aren't tight enough Packing is fully compressed Needle Point Valve - ANSType of globe valve, provides fine adjustment throttling Nominal outside diameter - ANSMeasures pipes from 1/8" to 12"

Packing varies with substance being sealed like: - ANSSteam Acids Caustics Solvents Petroleum products Pipe Measurements - ANSOD- outside diameter ID- Inside diameter OD-ID= Wall Thickness or Schedule Pipe Support- support weight of fluid and allow for expansion/contraction - ANSClamped support Roller support Spring/Cleve's support Piping connections - ANSThreads Welds Brazing Flanges Compression fittings Flared fittings Solder Cement

Piping systems - ANSConnect machinery and equipment: Sections of pipe Fittings to join piping Valves to control flow Other accessories like vents, drains, traps, strainers, gauges, relief valves Piping systems codes - ANSASME- American society of mechanical engineers ASTM- American society for testing and materials Reducing valves - ANSAutomatic valves used to reduce supply pressure to a lower discharge pressure; reduced pressure is maintained regardless of supply pressure changes Relief valves - ANSa pressure limiting device - prevent pressure from building up to a point where seals might burst; held closed by spring pressure; when system pressure overcomes spring pressure, pressure in system is relieved Riser - ANSVertical pipe line flows upward Run - ANSHorizontal line Simplex - ANSOnly one basket Strainers - ANSPrevent passage of grit and other foreign matter that could obstruct pump suction valves, throttle valves

Y-strainer - ANSprevents foreign particles from entering a reducing valve