Hydraulic Systems and Hydraulic Systems and ApplicationsApplications

ObjectivesObjectives

• Basic hydraulics theory. Basic hydraulics theory.

• Method of determination of output given Method of determination of output given input and configuration of given hydraulic input and configuration of given hydraulic systems.systems.

• Basic operation, principle components, and Basic operation, principle components, and safety considerations related to hydraulic safety considerations related to hydraulic systems.systems.

ReferencesReferences

• INEINE Chapter 15Chapter 15

Shipboard Hydraulic Shipboard Hydraulic SystemsSystems

• Steering gear (rudder, stern planes, etc.)Steering gear (rudder, stern planes, etc.)

• Deck machinery: Anchor windless, Deck machinery: Anchor windless, winches, capstanswinches, capstans

• Weapons systems: Gun mounts, launchersWeapons systems: Gun mounts, launchers

• Other applications: Hydraulic presses, Other applications: Hydraulic presses, ramps, elevators, catapult retractor, blast ramps, elevators, catapult retractor, blast shields, valve operations, etc. shields, valve operations, etc.

Properties of LiquidsProperties of Liquids

• ShapelessnessShapelessness– No natural shapeNo natural shape– Conforms to the shape of the containerConforms to the shape of the container

• IncompressibilityIncompressibility

• Transmission of forceTransmission of force– Force is equally distributed throughout the Force is equally distributed throughout the

liquid in all directionsliquid in all directions

PASCAL’S LAWPASCAL’S LAW

Pressure in a fluid acts Pressure in a fluid acts equally in all directionsequally in all directions

PRESSURE = FORCE/AREA

Find PressureFind F2

F2 =

F1 = 20 lbf

A1 = 2 in2

A1 = 20 in2

Pressure = 10 psi

200 lbf

Simple Hydraulic SystemSimple Hydraulic System

• Reservoir - Storage TankReservoir - Storage Tank

• Pressure source - Hydraulic pump (A-end)Pressure source - Hydraulic pump (A-end)

• Pressure user - (B-end)Pressure user - (B-end)– Hydraulic motor - rotary motionHydraulic motor - rotary motion– Hydraulic cylinder - linear motionHydraulic cylinder - linear motion

• Piping systemsPiping systems– valves, filters, heat exchangersvalves, filters, heat exchangers

• Accumulator - stores pressurized oilAccumulator - stores pressurized oil

• Hydraulic fluid (normally oil)Hydraulic fluid (normally oil)

Advantages of Using Oil Advantages of Using Oil As a Hydraulic FluidAs a Hydraulic Fluid..

• Non-corrosiveNon-corrosive

• Superb lubricantSuperb lubricant

Basic HydraulicsBasic Hydraulics

Axial Piston, Variable Axial Piston, Variable Stroke PumpsStroke Pumps

• Waterbury PumpWaterbury Pump– Electric MotorElectric Motor– Rotary Piston hydraulic pump/motorRotary Piston hydraulic pump/motor

• Hydraulic pump ("A" end)Hydraulic pump ("A" end)

• Hydraulic motor ("B" end)Hydraulic motor ("B" end)

Variable Stroke PumpVariable Stroke Pump“A End”“A End”

““A End”A End”

““B End” PistonB End” Piston

PistonPiston CylinderCylinder RAMRAM

Hydraulic Fluid Supply/Return PortsHydraulic Fluid Supply/Return Ports

SealSeal

Advantages of Advantages of Hydraulic SystemsHydraulic Systems

• Convenient method of power transmission Convenient method of power transmission over long distancesover long distances

• Great flexibilityGreat flexibility

• Variable speed controlVariable speed control

• Safety and reliabilitySafety and reliability

Disadvantages of Disadvantages of Hydraulic SystemsHydraulic Systems

• Need for positive confinement Need for positive confinement

• Fire hazard if leaks occurFire hazard if leaks occur

• Leaks in high pressure systems pose a Leaks in high pressure systems pose a safety hazardsafety hazard

• Adequate oil filtration must be maintainedAdequate oil filtration must be maintained

Steering UnitSteering Unit

Methods of Steering Methods of Steering ControlControl

• Normal control from ship's bridgeNormal control from ship's bridge– Utilizes remote electrical signal to control tilt-box Utilizes remote electrical signal to control tilt-box

position of hydraulic pumpposition of hydraulic pump

• Alternate control from after steeringAlternate control from after steering– "Trick wheel” manually operated to control tilt-box "Trick wheel” manually operated to control tilt-box

angleangle

• Emergency control Emergency control – Hand pump - Manually pressurizes hydraulic fluid to Hand pump - Manually pressurizes hydraulic fluid to

take local control of ruddertake local control of rudder

SummarySummary