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.

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

Ram unitRam unit

• TillerTiller- Converts linear motion to radial motion, aka - Converts linear motion to radial motion, aka crossheadcrosshead

• Rudder postRudder post- penetrates the hull, supports the rudder - penetrates the hull, supports the rudder and is connected to the tiller.and is connected to the tiller.

• Ram- Ram- operated by opposed cylinders these cylinders operated by opposed cylinders these cylinders work in unison to move the yoke/links/tillers/rudders, work in unison to move the yoke/links/tillers/rudders, simultaneous suction and discharge (waterbury pump)simultaneous suction and discharge (waterbury pump)

• Connecting linksConnecting links- transfers power from the ram and yoke to the - transfers power from the ram and yoke to the tillertiller

• Hand PumpHand Pump - - upon failure of the waterbury hydraulic upon failure of the waterbury hydraulic pump the hand pump system can be engaged to “set” the pump the hand pump system can be engaged to “set” the rudder. rudder.

Power unitPower unit• Electric motorElectric motor- prime mover for the waterbury - prime mover for the waterbury

hydraulic pumphydraulic pump

• Waterbury pump-Waterbury pump- Positive displacement pump, Positive displacement pump, variable stroke, consists of cylinder barrel, socket ring, and variable stroke, consists of cylinder barrel, socket ring, and tilting box. No tilt-no pumping, tilt-suction from one side tilting box. No tilt-no pumping, tilt-suction from one side and discharge to the otherand discharge to the other

• Transfer valvesTransfer valves- fixed to the cylinder barrel to direct - fixed to the cylinder barrel to direct oil suction and dischargeoil suction and discharge

• Remote steering unitRemote steering unit- A portable steering input for the - A portable steering input for the steering gear when the Ship’s Control Console is steering gear when the Ship’s Control Console is inoperative.inoperative.

• Trick WheelTrick Wheel- bypasses the electrical signal of the SCC, - bypasses the electrical signal of the SCC, control is in after steering. control is in after steering.

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