hydraulic&pneumatic (new)

7/29/2019 Hydraulic&Pneumatic (New)

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HYDRAULICS SYSTEM

DEALS WITH GENERATION, TRANSMISSION AND CONTROL OF

POWER USING PRESSURISED FLUID (BY VIRTUE OF PASCALS LAW)

PNEUMATIC SYSTEM

DEALS WITH TRANSMISSION AND CONTROL OF POWER USING

PRESSURISED AIR.

ELECTRICAL SYSTEM

DEALS WITH TRANSMISSION AND CONTROL OF HYDRAULIC AND

PNEUMATIC SYSTEM.


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ObjectivesAt the end of the course the candidate should be

able to Understand & explain :

The basics of hydraulics & pneumatics

The comparison between electric , hydraulic &

pneumatic systems

Various components of a typical hydraulic and

pneumatic circuit alongwith their symbols

The working & construction of various hydraulic &

pneumatic system components

Some simple hydraulic & pneumatic circuits

Some shipboard application of hydraulics & pneumatics

Practical demonstration


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USES OF HYDRAULICS

Shipboard systems using hydraulic power

Steering gear: rudder, fairwater and stern planes

Deck machinery: anchor windlass, capstans,

winches, etc. Valve Actuators

Mast and antennas on submarines

Weapons systems: munitions loading and

launching(guns, missiles, and torpedoes)

Other: presses, elevators

3


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PROPERTIES OF LIQUIDS

Shapelessness

No natural shape

Conforms to the shape of the container

Incompressibility

Transmission of force

Force is equally distributed throughout theliquid

Fluid we use: 2190 TEP

4


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PASCALS LAW

Pressure in a fluid acts equally in

all directions


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F2 =

F1 = 20 lbf

A1 = 2 in2

A1 = 2 0 in2

PRESSURE =

FORCE/AREA

Find Pressure

Find F2


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COMPARISONS OF

ELECTRICAL, HYDRAULIC AND PNEUMATIC SYSTEMS

Electrical Hydraulic Pneumatic

Energy storage

Usually from

outside supplierElectric motor or

diesel driven

Electric motor

or diesel drivenLimited (batteries) Limited

(accumulator)

Good (reservoir)

Lowest Medium Highest

Energy source

Energy costRotary actuators

Linear actuators

Controllable force

AC & DC motors. Low speed, Good Wide speed rangeGood control on control. Can be Accurate speedDC motors. stalled control difficult

Short motion via Cylinders, Very Cylinders.solenoid high force Medium force

Possible with Controllable high Controllablesolenoid & DC force Medium force

fire hazard


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WORKING LINE

PILOT LINE

DRAIN LINE

CROSSING

WORKING LINE

CROSSING WORK &

PILOT LINE

CROSSING DRAIN LINE

GRAPHIC SYMBOLS OF VARIOUS COMPONENTS


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ELECTRIC LINE

FLEXIBLE LINES

RESERVOIR

PIPE TERMINATED

BELOW FLUID LEVEL

PIPE TERMINATED ABOVE

FLUID LEVEL


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ENERGY FLOW HYDRAULIC

ONE DIRECTION ONLY

ENERGY FLOW HYDRAULIC

BOTH DIRECTIONS

ENERGY FLOW PNEUMATIC

BOTH DIRECTIONS

ENERGY FLOW PNEUMATIC

ONE DIRECTION

FIXED RESTRICTION


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BASIC PUMP SYMBOL

FLOW LINES CONNECTED

TO PUMP

SHAFT TURNS IN ONE

DIRECTION

SHAFT TURNS IN BOTH

DIRECTIONS


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HYDRAULIC PUMP

UNIDIRECTIONAL

HYDRAULIC PUMP

BIDIRECTIONAL

VARIABLE DISPLACEMENT

UNIDIRECTIONAL


BIDIRECTIONAL


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HYDRAULIC MOTOR

UNIDIRECTIONAL

HYDRAULIC MOTORBIDIRECTIONAL


UNIDIRECTIONAL


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PRESSURISED RESERVOIR

TEMP. GAUGE

FLOW METER


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ACCUMULATOR

LUBRICATOR

AUTO DRAIN


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M

M

ELECTRIC MOTOR

HEAT ENGINE

FREE FLOW IN ONE DIRN,

RESTD IN OTHER

PILOT LINE


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COOLER

HEATER

MANUAL SHUT OFF VALVE

VARIABLE FLOW CONTROL

VALVE


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ab

aob

TWO POSITION VALVE

THREE

POSITION VALVE

DIRECTIONAL CONTROL VALVES


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P

A

T

A

P

2\2 WAY VALVE

3\2 WAY VALVE


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P T

BA

4\2 WAY VALVE

4\3 WAY VALVE

P T

A B


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S P R

B A

S P R

B A

5\2 WAY VALVE

5\3 WAY VALVE


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P T

A B

PROPORTIONAL

VALVE (4\3)


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CYLINDERS

SINGLE ACTING

DOUBLE ACTING


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DIRECTIONAL CONTROL VALVES

THESE VALVES, AS THEIR

NAMES IMPLIES, CONTROL THE DIRECTION OF

FLOW OF THE FLUID IN THE SYSTEM.

THESE ARE OF THREE TYPES :-A. POSITIVE SEATED TYPE : IN WHICH A BALL

OR PISTON MOVES ON OR OFF THE SEAT.

B. ROTORY SPOOL TYPE : IN WHICH THE

SPOOL ROTATES ABOUT ITS OWN AXIS.

C. SLIDING SPOOL TYPE : IN WHICH THE

SPOOL MOVES AXIALLY IN A BORE.


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3/2 WAY DIRECTIONAL CONTROL

VALVE (POPPET)


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3/2 WAY DIRECTIONAL CONTROL VALVA (POPPET)


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VALVE (SPOOL)


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VALVE (SPOOL)


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R A

PB

ROTOR

R A

P B

A R

P BOFF


VALVE (ROTARY)


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PILOT OPERATED VALVES

LARGE CAPACITY PNEUMATIC VALVES AND

HYDRALIC VALVES, THE OPERATING FORCE

REQUIRED TO MOVE THE VALVE IS LARGE. IF

THE REQUIRED FORCE IS TOO LARGE FOR A

SOLONOID OR MANUAL OPERATION, A TWO

STAGE PROCESS CALLED PILOT OPERATION IS

USED.


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PILOT OPERATED VALVE


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SEQENCING VALVE

SEQUENCE VALVE IS A CLOSE RELATIVE OF THE

PRESSURE RELIEF VALVE AND IS USED WHERE

ASET OF OPERATIONS ARE REQUIRED TO BE

CONTROLLED IN A PRESSURE RELATED

SEQUENCE.


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33SEQUENCING VALVE


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CHECK VALVES

CHECK VALVES ONLY ALLOW FLOW IN ONE

DIRECTION AND, AS SUCH ARE SIMILAR INOPERATION TO ELECTRONIC DIODES.


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CHECK

VALVE

RIGHT ANGLE

CHECK VALVE


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TIME DELAY VALVE

TIME DELAY VALVES ARE USED TODISPLAY OPERATIONS WHERE TIME BASED

SEQUENCES ARE REQUIRED. THE TIME

DELAY CAN BE ADJUSTED BY THE NEEDLE

VALVE SETTING AS PER REQUIREMENT.


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TIME DELAY VALVE


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SHUTTLE VALVE

A SHUTTLE VALVE, ALSO KNOWN AS A

DOUBLE CHECK VALVE, ALLOWS

PRESSURE IN A LINE TO BE OBTAINED

FROM ALTERNATIVE SOURCES. IT IS

PRIMARILY A PNEUMATIC DEVICE AND IS

RELY FOUND IN HYDRAULIC CIRCUITS.


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SHUTTLE VALVE


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EXHAUST VALVE

EXHAUST VALVES ARE USED TO VENT

CYLINDERS QUICKLY. THESE VALVES ARE

USUALLY MOUNTED LOCAL TO, OR DIRECTLY

ONTO, CYLINDERS AND SPEED UPRESPONSE BY AVOIDING ANY DELAY FROM

RETURN PIPES AND CONTROL VALVES.


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EXHAUST VALVE


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PROPORTIONAL VALVE

INPUT AND OUTPUT SINGAL.

ORIFICE/GROVES ARE PROVIDED ON SPOOL.

EXTERNAL CIRCUIT REQUIRED e.g OPAM.

HIGH CURRENT REQUIRED 120 TO 800mA.

CLOSE LOOP AS WELL AS OPEN LOOP.

2-10% OF DEAD BAND i.e +ve DEAD BAND


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PRO


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RESTRICTORS

RESTRICTORS ARE USED IN THE

HYDRAULIC AND PNEUMATIC SYSTEM TO

CONTROL THE SPEED OF ACTUATORS BY

ADJUSTING THE RATE AT WHICH A FLUIDISADMITTED TO A DEVICE.

THESE ARE OF TWO TYPES:

FIXED RESTRICTORS

VARIABLE RESTRICTORS


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MOTION DETECTORS

THESE ARE BASICALLY PILOT VALVES USED INPNEUMATIC SYSTEM FOR PILOT OPERATIONS,WHICH CONVERT MECHANICAL MOTION INTOPRESSURE CHANGE.

THESE ARE OF TWO TYPES:-

BLEED TYPE

(i) DIRECT ACTING(ii) REVERSE ACTING

NON-BLEED TYPE


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BAFFLE/NOZZLE

BAFFLE/NOZZLE IS THE HEART OF ALL

PNEUMATIC PROCESS CONTROL DEVICES

TO CONVERT A SMALL DISPLACEMENT INTOA PRESSURE CHANGE, WHICH REPRESENTS

THE PROPERTY CAUSING THE

DISPLACEMENT INTO A PRESSURE CHANGE.


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AIR RELAY

DIRECT ACTING- BLEED TYPE

AIR RELAY BALANCES INPUT PRESSURE WITH

HE FORCE FROM THE RANGE SPRING. AN

INCREASING SIGNAL CAUSES AIR TO PASS

FROM THE SUPPLY TO THE LOAD, WHILE A

DECREASING INPUT SIGNAL CAUSES AIRTOVENTILATE FROM THE LOAD.


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PUMPS

A PUMP TAKES OIL FROM A TANK AND DELIVERS ITTO THE REST OF THE HYDRAULIC CIRCUIT WITH

RAISING OIL PRESSURE TO THE REQUIRED LEVEL.

THERE ARE THREE TYPES OF POSITIVEDISPLACEMENT PUMPS USED IN HYDRAULICSYSTEMS.

- GEAR PUMPS

- VANE PUMPS

- PISTON PUMPS


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GEAR PUMP


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PISTON PUMP


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HYDRAULIC RESERVOIR


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A HYDRAULIC SYSTEM IS CLOSED, AND THE OIL

USED IS STORED IN A TANK OR RESERVOIR TOWHICH IT IS RETURNED AFTER USE.

THE MAIN FUNCTIONS OF THE RESERVOIR IN A

HYDRAULIC SYSTEM ARE TO STORE AND SUPPLY HYDRAULIC FLUID

TRANSFERING OF WASTE HEAT.

AS A DEAERATOR.

USED AS A PLATFORM.


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DRAIN

RETURN

TO

PUMP

ACCESS

PLATE

COARSE

FILTER

BAFFLE

PLATE

DRIP

TRAY

ACCUMULATOR


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IT IS A RESERVOIR OF OIL AT SUPPLY

PRESSURE. THE OIL IN IT IS PRESSURISED

BY A BAG OF NITROGEN GAS.

THE BAG IS PRE-CHARGED WITH GAS TO

A PRESSURE OF HALF THE (PRESSURE

OF) SYSTEM PRESSURE.

FORCING OIL IN AT SYSTEM PRESSURE

GAS IS COMPRESSED INSIDE THE

ACCUMULATOR.

GASCHARGING


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CHARGING

VALVE

GAS

FLUID

BLADDER

POPPETVALVE

PRESSURE

SWITCHTO SYSTEM

PRESSURE CONTROL VALVES


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THESE VALVES ARE USED TO REGULATE FLUIDPRESSURE. THERE ARE TWO MAIN TYPES

PRESSURE OF CONTROL VALVES.

A. PRESSURE RELIEF VALVE

B. PRESSURE REDUCING VALVE

THE BASIC DIFFERENCE BEING THAT THE

RELIEF VALVE IS CLOSED BY THE SPRING, ANDTHE REDUCING VALVE OPENED BY THE SPRING.


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PRESSURE RELIEF VALVE


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TWO WAY PRESSURE REGULATING


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THREE WAY PRESSURE

REGULATOR

DESIGN OF SIMPLE PNEUMATIC CIRCUIT


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DESIGN OF SIMPLE PNEUMATIC CIRCUIT

DESIGN OF SIMPLE HYDRAULIC CIRCUIT


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DESIGN OF SIMPLE HYDRAULIC CIRCUIT

PNEUMATIC AND HYDRAULIC CONTROL SYSTEM


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PNEUMATIC AND HYDRAULIC CONTROL SYSTEM

OF CPP

SYSTEM IS USED TO CONTROL THE PROPELLER

PITCH IN BOTH DIRECTIONS FROM ZERO TO

MAXIMUM.

MAIN PARTS OF THE SYSTEM

PUMPS : PROVIDED WITH TWO PUMPS. WHENLEAD PUMP FAILS, MOTOR DRIVEN PP. (STAND BY)

TAKES OVER THE CONTROL.


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PROPELLER :

SYSTEM ISPROVIDED WITH FIVE REMOVABLE

BLADES BOLTED TO THE AFT FLANGE OF THE

PROPELLER SHAFT.


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PNEUMATIC SYSTEM HYGIENE

AIR INLET FILTER TO BE CHECKED/CLEANED.

AIR BOTTLE TO BE DRAINED DAILY.

LUB OIL SEPERATOR TO BE DRAINED REGULARLY.

CLEAN FILTERS FITTED IN SYSTEM.

CHECK THE LEVEL OF OIL IN THE AIR SEPERATOR.

CHECK FOR LEAKAGE IN THE SYSTEM.

CHECK THE NEEDLE VALVE OF THE FILTER.

CHECK SAFETY VALVE OPERATION PERIODICALLY.


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HYDRAULIC SYSTEM HYGIENE

INSPECT FILTER ELEMENTS

DO NOT USE LEAKED FLUID KEEP FRESH FLUID SAFE

USE CLEAN CONTAINERS, FUNNELS ETC.

KEEP OPEN COMPONENTS FREE FROM

DIRT

USE PROPER FLUID AS RECOMMENDED


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KEEP NAKED FLAMES AWAY FROM THE

SYSTEM.

USE PROPER FLUID AS RECOMMENDED

ALWAYS RUN SYSTEM WITH FILTERELEMENTS

CHECK SAFETY VALVE OPERATION

PERIODICALLY.

CARRY OUT FLUID ANALYSIS

PERIODICALLY

COMMON FAULTS IN HYDRAULIC &


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COMMON FAULTS IN HYDRAULIC &

PNEUMATIC SYSTEMS

HYDRAULICS EXCESSIVE VIBRATION OF PUMP.

PUMP NOT DEVELOPING PRESSURE.

ACTUATOR NOT MOVING.

SYSTEM NOT RESPONDING.

EXCESSIVE OIL TEMPERATURE.

DIFFERENTIAL PRESSURE TOO HIGH.

HUNTING OF SYSTEM


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PNEUMATICS

EXCESSIVE VIBRATION OF COMPRESSURE.

COMPRESSURE NOT DEVELOPING RESSURE.

ACTUATOR NOT MOVING.

SYSTEM NOT RESPONDING

FAULT DETECTION TECHNIQUES


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FAULT DETECTION TECHNIQUES

INCORRECT FLOWNO FLOW LOW FLOW EXCESSIVE FLOW

PP NOT RECEIVING

FLUID

FLOW CONTROL

V V. SET TOO LOW

FLOW CONTROL VALVE

SET TOO HIGH

PP DRIVE MOTOR

NOT OPERATING

RELIEF VALVE SET

TOO LOW

YOKE ACTUATING

DEVICE INOPERATIVE

PP TO DRIVE

COUPLING SHEARED

FLOW BYPASSING RPM OF MOTOR

INCORRECT

D.C. VALVE SET IN

WRONG POSITION

RPM OF MOTOR

INCORRECT

INPROPER SIZE OF PP

USED TO REPLACE PP.

FLOW PASSINGOVER RELIEF VALVE EXTERNALLEAKAGE


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INCORRECT PRESSURELOW PRESSURE ERRATIC PRESSURE EXCESSIVE PR.

PRESSURE RELIEF

V V EXISTS.

AIR IN FLUID. PR. RELIEF V V

MIS-ADJUSTMENT.

PR. REDUCING V V

SET TOO LOW.

WORN RELIEF VALVE. PR. REDUCING V V

DAMAGED.

PR.REDUCING V V

DAMAGED.

CONTAMINATED FLUID.

PUMP DAMAGED. DEFECTIVE PUMP.

hydraulic&pneumatic (new)

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