Lesson 14 hydraulics
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Hydraulics is the study of fluids at rest or in motion, especially regarding engineering applications. Hydraulic systems use pressurized fluids to gain mechanical advantage and perform work. Key components include hydraulic pumps that generate pressure, motors or cylinders that convert pressure into motion, and piping to transmit fluid. Hydraulics offers advantages like convenient power transfer with few moving parts and flexibility to distribute force in multiple directions. Common uses include steering, deck machinery, masts/antennas, weapons, and elevators/presses. Basic hydraulic theory involves properties like fluids conforming to containers and transmitting force equally in all directions according to Pascal's law.
![HydraulicsHydraulics
hy·drau·lics [hy·drau·lics [hh drólliksdrólliks ]] nounnoun
study of fluids: the study of water orstudy of fluids: the study of water or
other fluids at rest or in motion,other fluids at rest or in motion,
especially with respect to engineeringespecially with respect to engineering
applicationsapplications](https://image.slidesharecdn.com/lesson14-hydraulics-150531034404-lva1-app6891/85/Lesson-14-hydraulics-1-320.jpg)
Lesson 14 hydraulics
- 1. HydraulicsHydraulics hy·drau·lics [hy·drau·lics [hh drólliksdrólliks ]] nounnoun study of fluids: the study of water orstudy of fluids: the study of water or other fluids at rest or in motion,other fluids at rest or in motion, especially with respect to engineeringespecially with respect to engineering applicationsapplications
- 2. ObjectivesObjectives • Behavior of liquids & theory of operation • Basic hydraulic system components • Advantages & disadvantages of hydraulics • Electrohydraulic systems including speed gears & steering gears
- 3. Introduction/UsesIntroduction/Uses • Hydraulics used in many applications: • Steering/control systems (rudder, planes) • Deck machinery (anchor windlass, capstans, winches) • Masts & antennae on submarines • Weapons systems (loading & launching) • Other: elevators, presses
- 4. Hydraulic TheoryHydraulic Theory • Hydraulics • Covers the physical behavior of liquids in motion • Pressurized oil used to gain mechanical advantage and perform work • Important Properties • Shapelessness • Incompressibility • Transmission of Force
- 5. Important PropertiesImportant Properties • ““Shapelessness”Shapelessness” • Liquids have no neutral form • Conform to shape of container • Easily transferred through piping from one location to another • IncompressibilityIncompressibility • Liquids are essentially incompressible • Once force is removed, liquid returns to original volume (no permanent distortion) • Transmission of ForceTransmission of Force • Force is transmitted equally & undiminished in every direction -> vessel filled with pressure
- 6. Hydraulic TheoryHydraulic Theory • Pascal’s Law • Magnitude of force transferred is in direct proportion to the surface area (F = P*A) • Pressure = Force/AreaPressure = Force/Area • Liquid properties enable large objects (rudder, planes, etc) to be moved smoothly
- 7. Hydraulic Mechanical AdvantageHydraulic Mechanical Advantage F2 = F1 = 20 lbf A1 = 2 in2 A1 = 20 in2
- 8. Basic Hydraulic SystemBasic Hydraulic System • Hydraulic Fluid • Usually oil (2190 TEP) • Pressure Source • Hydraulic pump (A-end of system) • Pressure user • Hydraulic motor (B-end of system) • Piping system (w/ valves, tanks, etc) • Get fluid from A-end to B-end
- 9. Hydraulic Pump (A-End)Hydraulic Pump (A-End) • Pumps can be positive displacement or centrifugal •Waterbury pump •Variable-stroke piston pump •Tilting box can tilt fwd/aft while pump rotates •Angle of tilting box determines capacity and direction of oil flow
- 10. Hydraulic Pump (A-End)Hydraulic Pump (A-End) •Variable-stroke piston pump •Tilting box can tilt fwd/aft while pump rotates •Angle of tilting box determines capacity and dir. of flow
- 11. Cylinder/Motor (B-end)Cylinder/Motor (B-end) • Piston/cylinder used if desired motion is linear • Hydraulic pressure moves piston & ram • Load is connected to ram (rudder, planes, masts, periscopes) PistonPiston CylinderCylinder RAMRAM Hydraulic Fluid Supply/Return PortsHydraulic Fluid Supply/Return Ports SealSeal
- 12. Cylinder/Motor (B-end)Cylinder/Motor (B-end) • Motor used if desired motion is rotary • Essentially a variable- stroke pump in reverse • Used for capstan, anchor windlass, etc
- 13. Piping SystemPiping System • Has to withstand excessive pressure • Valves, filters, & HX’s all necessary • Accumulators • Holds system under pressure (w/out contin. pump) • Provides hydraulics when pump off/lost • Compensates for leakage/makeup volume • Types: piston, bladder, & direct contact
- 14. Accumulator TypesAccumulator Types • Piston • Most common • Bladder • Gun mounts • Steering systems • Direct contact • Least common
- 15. AdvantagesAdvantages • Convenient power transferConvenient power transfer • Few moving parts • Low losses over long distances • Little wear • FlexibilityFlexibility • Distribute force in multiple directions • Safe and reliable for many uses • Can be stored under pressure for long periods • Variable speed controlVariable speed control • Quick response (linear and rotary)
- 16. DisadvantagesDisadvantages • Requires positive confinement (to give shape) • Fire/explosive hazard if leaks or rupturesFire/explosive hazard if leaks or ruptures • Filtration critical - must be free of debris • Manpower intensive to clean up
- 17. Electrohydraulic Drive SystemElectrohydraulic Drive System • Uses hydraulics to transfer power from electric motor to load • Rotary: Waterbury pump connected to rotary piston hydraulic motor (speed gear) • Tilting box of A-end controls direction/speed of B-end • Adv: high starting torque, reversibility, high power-to- weight ratio • ex: Electrohydraulic Speed Gear or Steering Gear • capstan, anchor windlass, cranes, elevator, ammo hoist
- 18. Electrohydraulic Speed GearElectrohydraulic Speed Gear
- 19. Electrohydraulic Steering GearElectrohydraulic Steering Gear • Same as speed gear except B-end is a hydraulic cylinder to produce linear motion • Waterbury pumps connected by piping to hydraulic ram cylinder • Various methods for connecting rams to tillers • Two pumps for redundancy & reliability • Movement of steering wheel through hydraulic system moves rudder
- 20. Electrohydraulic Steering GearElectrohydraulic Steering Gear
- 21. Control of SystemControl of System • Remote control • Normal method • Control from bridge • Emergency • Take local control • Manually position control surface/rudder