CT02 BASIC HYDRAULICS

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Introduction to Hydraulics

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UTCUTC

Module CT02


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Objective

In this module, you will learn :

CTU Hydraulic systems.

Advantage of hydraulic systems.

Principal and operation of hydraulic circuits.

Operation and application for each basic component.


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CTU Hydraulic Pumps

Pump Circuit Pressure

(PSI)

Pump Flow Rate

(GPM)

Injector - 1 3,000 30

Injector - 2 3,000 60

Reel 2,500 16

Level Wind(Override)

2,500 30

BOPs 3,000 12

Priority 2,000 12

Aux. 3,000 30


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What is Hydraulics ?

Hydraulics is the study of devices that use the pressure in

a confined fluid to generate, transmit, and control power.

A device that uses the impact or kinetic energy in a liquid to

transmit power is a hydrodynamic device. e.g the water-wheel

(Pelton turbine)

A device operated by the force applied to a confined liquid is a

hydrostatic device. (eg. a hydraulic car-jack)


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Fundamentals

Pascals Law

Pressure applied on a confined fluid is transmitted undiminished in

all directions, and acts with equal force on equal areas, and at

right angles to them.

Law of Conservation of Energy

Energy can neither be created nor destroyed.

Bernoullis principle

If the flow rate is constant, the sums of the kinetic energy andpressure energy at various points in a system are constant.


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Mechanical Advantage

1 sq. in. 8 sq. in.

100 lbs800 lbs

800 lbs100 lbs

8 ft 1 ft


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Advantages of Hydraulic Systems

Variable speed

Reversible

Overload protection / stalling

High bhp/kg ratios

Reliability and ease of maintenance

Flexibility of placement


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Hydraulic Fluid

Transmits power

Low viscosity - hence low friction.

Incompressible

Lubricates

All hydraulic components internally lubricated Seals

Metal-to-meal seals work because of close tolerances and

viscosity of hydraulic oil.

Cools

And... Additional properties such as resistance to foaming, protection

against rust and oxidation


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Viscosity

Viscosity is the measure of the fluids resistance to flow.

A high viscosity is desirable for maintaining seal between

mating surfaces. But...

Too high a viscosity will lead to high friction, increased powerlosses, higher operating temperatures.

Too low a viscosity will cause increased internal leakage, lower

pump efficiency, and possible breakdown of oil under heavy loads.

Typical hydraulic grades - ISO32, or SAE10W


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Symbols

Pump Motor

Relief valve

Reservoir

A pilot line operates a valve

or other controls Pressure line is a

working line


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Symbols

Single Acting Cylinder Double Acting Cylinder

Piston Rod

Hydraulic Rams


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Symbols

IN

OUT

Pilot Line denotes

operation by pressure

Arrow showes flow path

and direction

Relief valve (Infinite Positioning)

Arrow indicates

adjustable


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Symbols

Port Connections aredrawn to center or neutral

position

Three envolopes means

the valve has three positions

Arrows show flow

path and direction

Directional Valve (Finite Positioning)


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Symbols

Horizontal bars

indicates infinite

positioning ability

Directional Valve (Infinite Positioning)


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Check Valve

IN OUT


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2 Way Spool Valve

Pr to B

A Blocked

A B

Pr to A

B Blocked

A B

A B

P T


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4 Way Spool Valve

Pr to B

A to tank

A B

Pr to A

B to tank

A B

A B

TP


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Direct Acting ReliefValve


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Balanced Piston ReliefValve


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Pilot-operated pr.-reducing valve


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Unloading Valve


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Counter Balance Valve


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Vanes

Drive shaft Rotor

system pressure

pressure on this vanegives rise to a force

the force acting on the vanecreates a torque on the shaft


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Vane Motor - Unbalanced


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Vane Motor - Balanced


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In-Line Pistons Motor

oil under pressure

at the inlet...

swash plate

drive shaftshoe retainer plate

pistonscylinder block


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Vane Pump


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Vane Pump - Contd...


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Gear Pump


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Lobe Pump


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Radial Pistons Motor


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Reservoir

Stores and supplies hydraulic fluid

Size (gal) > 2xpump(gpm) < 3xpump(gpm)

Allows oil to cool

Baffle plate enhances cooling, prevents turbulence

Conditions hydraulic fluid

Allows contaminants to settle down

Allows entrained air to escape


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Excercise - 1

Draw a hydraulic circuit to operate Bi-Directional

motor and dual acting ram.


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Solution

Reservoir

LoadLoad


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Excercis - 2

Draw a Hydraulic Circuit to operate a bi-directional motor at

different RPM (Max Pressure 2500 psi), also to supply not more

than 600 psi to a selection valve.

One of the trainees to draw it on the board.

Documents

CT02 BASIC HYDRAULICS