PUMPS, VALVES, PUMPS, VALVES, & FANS& FANS

……Moving fluidsMoving fluids

ObjectivesObjectives• Comprehend the basic construction Comprehend the basic construction

and application of valves usedand application of valves used• Comprehend the basic operation and Comprehend the basic operation and

application of different pumpsapplication of different pumps• Know Bernoulli’s principle, the Know Bernoulli’s principle, the

concept of pressure, & Net Positive concept of pressure, & Net Positive Suction HeadSuction Head

• Be familiar with operation and Be familiar with operation and application of centrifugal & axial fansapplication of centrifugal & axial fans

ValvesValves• Def’n: devices which control the Def’n: devices which control the

amount and direction of fluid flow in amount and direction of fluid flow in piping systemspiping systems• Typically made of bronze, brass, iron, Typically made of bronze, brass, iron,

or steel alloyor steel alloy• Components:Components: - Valve body- Valve body - Packing- Packing - -

DiscDisc - Packing gland/nut- Packing gland/nut- Seat- Seat - Stem- Stem - Bonnet- Bonnet - Wheel - Wheel

Types of ValvesTypes of Valves• Two basic groups:Two basic groups:

• Stop valves - used to shut off or Stop valves - used to shut off or partially shut off the flow of fluid ( ex: partially shut off the flow of fluid ( ex: globe, gate, plug, needle, butterfly)globe, gate, plug, needle, butterfly)

• Check Valves - used to permit flow in Check Valves - used to permit flow in only one direction (ex: ball-check, only one direction (ex: ball-check, swing-check, lift-check)swing-check, lift-check)

• Special types:Special types:• Relief valvesRelief valves• Pressure-reducing valvesPressure-reducing valves• Remote-operated valvesRemote-operated valves

Stop ValvesStop Valves• Globe ValvesGlobe Valves

• Most common type of stop valveMost common type of stop valve• Used in steam, air, water, & oil Used in steam, air, water, & oil

lineslines• Disc attached to valve stem rests Disc attached to valve stem rests

against seat to shut off flow of against seat to shut off flow of fluidfluid

• AdvAdv: Used for throttling: Used for throttling• DisadvDisadv: flow resistance: flow resistance

Globe ValveGlobe Valve

Stop ValvesStop Valves• Gate ValvesGate Valves

• Used when there must be Used when there must be straight-line flow of fluid w/ min. straight-line flow of fluid w/ min. resistanceresistance

• Gate usually wedge-shaped or a Gate usually wedge-shaped or a vertical discvertical disc

• AdvAdv: No flow restrictions: No flow restrictions• DisadvDisadv: poor throttling: poor throttling

Gate ValveGate Valve

Stop ValvesStop Valves• Butterfly ValvesButterfly Valves

• Used in water, fuel, and ventilation Used in water, fuel, and ventilation systemssystems

• AdvAdv: small, light-weight, & quick-acting: small, light-weight, & quick-acting• DisadvDisadv: leaks early & only low-flow : leaks early & only low-flow

throttlethrottle• Ball ValvesBall Valves

• Similar to butterfly valvesSimilar to butterfly valves• Normally found in seawater, sanitary, Normally found in seawater, sanitary,

trim and drain, and hydraulic systemstrim and drain, and hydraulic systems

Butterfly ValveButterfly Valve

Check ValvesCheck Valves• Controls direction of flowControls direction of flow• Operated by flow of fluid in pipeOperated by flow of fluid in pipe• Types:Types:

• Swing check - disc moves through Swing check - disc moves through an arcan arc

• Lift check - disc moves up and downLift check - disc moves up and down• Ball check - ball is located at end of Ball check - ball is located at end of

stem and lifts to allow flowstem and lifts to allow flow

Swing-check ValveSwing-check Valve

Relief ValvesRelief Valves• Used to protect piping system Used to protect piping system

from excessive pressurefrom excessive pressure• Opens automatically when Opens automatically when

fluid pressure becomes too fluid pressure becomes too high (pressure acts against high (pressure acts against spring pressure)spring pressure)

• Relieving pressure set by an Relieving pressure set by an adjusting screwadjusting screw

Pressure-reducing Pressure-reducing ValvesValves

• Used to automatically provide Used to automatically provide a steady, lower pressure to a a steady, lower pressure to a system from a higher pressure system from a higher pressure sourcesource

• Used in air, lube-oil, seawater, Used in air, lube-oil, seawater, and other systemsand other systems

Remote-operated Remote-operated ValvesValves

• Valves that allow operation from Valves that allow operation from distant stationsdistant stations

• Types:Types:• Mechanical - uses reach rods and gearsMechanical - uses reach rods and gears• Hydraulic - uses fluid and piston set upHydraulic - uses fluid and piston set up• Motor - uses and electric or pneumatic Motor - uses and electric or pneumatic

motormotor• Solenoid - uses coil and core Solenoid - uses coil and core

mechanism to open or close on an mechanism to open or close on an electric signalelectric signal

PumpsPumps

PumpsPumps• Def’n: device that uses and Def’n: device that uses and

external power source to apply external power source to apply force to a fluid in order to move force to a fluid in order to move it from one place to anotherit from one place to another

• Must overcome:Must overcome:• (1) frictional forces from large (1) frictional forces from large

quantities of fluidquantities of fluid• (2) difference in static pressure (2) difference in static pressure

between two locationsbetween two locations• Must provide any velocity Must provide any velocity

desired desired

Pumps – Bernoulli’s Pumps – Bernoulli’s TheoremTheorem

• Pressure head: measure of fluid’s mech. PEPressure head: measure of fluid’s mech. PE• Velocity head: measure of fluid’s mech. KEVelocity head: measure of fluid’s mech. KE• Friction head: measure of energy lost that Friction head: measure of energy lost that

heats fluid heats fluid

ZZ11 + P + P11// + V + V1122/2g = Z/2g = Z22 + P + P22// + V + V22

22/2g + [(U/2g + [(U22 – U – U11) – W – Q]) – W – Q]

q + wq + wshaftshaft = (h = (h2 2 – h– h11) + (v) + (v2222 – v – v11

22)/2 + g(z)/2 + g(z22 –z –z11))

Z/z: fluid height;Z/z: fluid height; P: fluid pressure; P: fluid pressure; : fluid density : fluid density V/v: fluid velocityV/v: fluid velocity U: internal energyU: internal energy W/w: workW/w: workQ/q: heat transferredQ/q: heat transferred h: enthalpyh: enthalpy g: grav. accelerationg: grav. acceleration

• BOTTOM LINE: Total energy within the control BOTTOM LINE: Total energy within the control volume is constant under SS conditions.volume is constant under SS conditions.

Components of PumpsComponents of Pumps• Drive mechanism (steam, Drive mechanism (steam,

electric, gear)electric, gear)• Pump shaftPump shaft• Impeller or pistonImpeller or piston• CasingCasing

Types of PumpsTypes of Pumps• Positive DisplacementPositive Displacement

• Fixed volume of fluid is displaced Fixed volume of fluid is displaced during each cycle regardless of during each cycle regardless of static head/pressure pumping static head/pressure pumping againstagainst

• Uses either a piston, gear, or Uses either a piston, gear, or screw type (reciprocating, rotary screw type (reciprocating, rotary gear, rotary screw, etc)gear, rotary screw, etc)

Positive Displacement Positive Displacement PumpPump

PumpsPumps• Non-positive DisplacementNon-positive Displacement: :

volume of fluid is dependent on volume of fluid is dependent on static head/pressurestatic head/pressure• CentrifugalCentrifugal: impeller inside a case : impeller inside a case

(called volute). Impeller is a disc w/ (called volute). Impeller is a disc w/ curved vanes mounted radially (like curved vanes mounted radially (like a paddle wheel)a paddle wheel)

• Suction is the Eye -> fluid accelerated as it Suction is the Eye -> fluid accelerated as it travels outward & then enters volutetravels outward & then enters volute

• PropellerPropeller: uses prop inside casing to : uses prop inside casing to move fluid -> not used much in Navymove fluid -> not used much in Navy

Centrifugal PumpCentrifugal Pump

PumpsPumps• Jet pumpsJet pumps: :

• Bernoulli’s principle and no Bernoulli’s principle and no moving partsmoving parts

• Velocity Head vs. Pressure headVelocity Head vs. Pressure head

hin + vin2/2 = hout + vout

2/2

Jet PumpJet Pump• Types:Types:

• Eductor - used to pump liquidsEductor - used to pump liquids• Ejector - used to pump gasesEjector - used to pump gases

Pump Characteristic Pump Characteristic CurvesCurves

• Pump Parameters:Pump Parameters:• N = pump speed, RPMN = pump speed, RPM• V = volumetric flow rate, GPMV = volumetric flow rate, GPM• HHpp = pump head (discharge pressure), = pump head (discharge pressure),

psigpsig• P = power required, HpP = power required, Hp

• Centrifugal Pump LawsCentrifugal Pump Laws• V V N N• HHpp N N22

• W W N N33

Positive Displacement Positive Displacement Pumps Pumps

Hp

GPM

N1 N2

N2 = ____

Centrifugal PumpsCentrifugal Pumps• Parallel PumpsParallel Pumps

Hp

GPM

2 Pumps

1 Pump

V2 = ____

Hp2 = ____

Centrifugal PumpsCentrifugal Pumps• Series pumps (called staging)Series pumps (called staging)

Hp

GPM

V2 = ____

Hp2 = ____2 Pumps

1 Pump

FansFans• Same Principle as Non-positive Same Principle as Non-positive

displacement pumpsdisplacement pumps• Types:Types:

• Centrifugal: majority used for Centrifugal: majority used for compressorscompressors

• Axial (like propeller): cooling fansAxial (like propeller): cooling fans

FansFans

Questions?Questions?QuestionQuestion

s?s?