iii

DESIGN OF HYDRAULIC POWER PACK FOR SPECIAL PURPOSE 2-WAY BORING MACHINE

A project report submitted in the partial fulfillment for the award of Degree of

BACHELOR OF TECHNOLOGY

IN MECHANICAL ENGINEERING

Submitted by

V.VEERANJANEYULU

Roll No. 08063A3449

SCHOOL OF CONTINUING & DISTANCE EDUCATION

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY

HYDERABAD – 28

(2012)

iv

CERTIFICATE

This is to certify that the project report entitled DESIGN

OF HYDRAULIC POWER PACK FOR SPECIAL PURPOSE 2-WAY BORING MACHINE

that is being submitted by V.VEERANJANEYULU in partial fulfillment for the

award of the Degree of Bachelor of Technology in MECHANICAL

ENGINEERING to the Jawaharlal Nehru Technological University is a record of

bonafide work carried out by him under my guidance and supervision. The

results embodied in this project report have not been submitted to any other

University or Institute for the award of any degree or diploma.

Date:

SIGNATURE OF THE GUIDES:

Internal guide External guide

Y.VENKATNARAYANA MANOJ AGRAWAL

Asst. Professor Asst. Manager – ER&D, ED

Srinidhi Institute of Science & Technology. Hyderabad Industries Limited.

CHAIRMAN

PROJECT REVIEW COMMITTEE

(SRINIDHI INSTITUTE OF SCIENCE & TECHNOLOGY)

v

ACKNOWLEDGEMENT

It gives us immense pleasure to express my deep sense of gratitude to my external project

guide, Mr. MANOJ AGRAWAL, Asst. Manager in the Engineering Division of

HYDERABAD INDUSTRIES LIMITED, Hyderabad. For his valuable guidance, constant

encouragement, constructive criticism, simulative discussions and keen interest evinced through

out the course of the project. I am really fortunate to associate my self with such encouraging and

experienced guide.

I owe a deep sense of gratitude and sincere thanks to my internal guide

Mr.Y.VENKATNARAYANA department of Mechanical Engineering, Srinidhi Institute of

Science & Technology. My thanks extended to him for constant association, encouragement and

supervision in completing my project work.

K.DAMODHARAM

vi

ABSTRACT

This project is aimed at the design of hydraulic power pack for fixtures of 2-way line boring

machine. Use of hydraulic system for the purpose we ensure firm grip to the job and makes the

holding of the job much easier. It also is used to do some work like clamping, Transfer and

lifting of the component.

The power pack is an integral power supply unit usually containing a pump, reservoir, relief

valve and directional control valve. For the purpose of design of hydraulic power pack the

components that are to be designed are a pump, a reservoir, and an electric motor. The pump size

is selected by calculating the fluid flow rate, which is required by different cylinders to perform

various operations. By considering the discharge of fluid, the capacity of tank and the power of

the electric motor are calculated. The other parts like check valves, Oil cooler, flexible coupling,

seals etc. are selected as per the design requirements. Special emphasis is made on design of

power pack in which selection of elements, maintenance aspects, trouble –shooting methods is

dealt with.

Hydraulic drives and controls have become more importance due to automization and mechanization. Hydraulic system is less complicated and has fewer parts. Due to this fact, hydraulic systems are more advantageous than mechanical systems.

vii

CONTENTS

1. INTRODUCTION

1.1 BASICS OF HYDRAULICS

1.2 SPECIAL CHARACTERISTICS OF HYDRAULICS

1.3 FLUID POWER

1.4 BASIC PRINCIPLES

1.5 ADVANTAGES OF HYDRAULIC SYSTEM

1.6 APPLICATIONS OF HYDRAULICS

1.7 INTRODUCTION TO SPECIAL PURPOSE TWO WAY BORING MACHINE

1.8 INTRODUCTION TO HYDRAULIC POWER PACK (HPP)

1.9 WORKING OF HYDRAULIC POWER PACK

1.10 DESCRIPTION OF HYDRAULIC POWER PACK

1.11 DEFINITION OF HYDRAULIC COMPONENTS

1.12 HYDRAULIC SYMBOLS

2. LITERATURE SURVEY

3. DESIGN CALCULATIONS

4. SELECTION PROCEDURE

4.1 CIRCUIT DIAGRAM OF HYDRAULIC POWER PACK

4.2 BILL OF MATERIAL

5. HYDRAULIC FLUIDS

5.1 FLUID ANALYSIS BY USING ANSYS

viii

6. RESULTS

7. CONCLUSIONS

8. BIBLIOGRAPHY

9. APPENDICES

1

1. INTRODUCTION

A great diversity of methods is available of methods is available for transmitting

energy from a prime mover to a neighboring or a distant point. By, employing liquid under

pressure continues to make head way in face of today’s competition .on he basis of equal speeds

and outputs the hydraulic machine might be more compact and lighter than the electrical one.

Hydraulic transmission is prominent when the work to be done requires flow of steady thrust,

which can, if necessary be indefinitely maintained. When extremely heavy thrusts have to be

developed of the order of 5000-30000 tones nothing else but hydraulic machine, the system will

press the basic advantage of silence, simplicity, smoothness of operation and ease of control.

1.1 BASICS OF HYDRAULICS:

The word hydraulics is derived from the Greek word ‘Hydro’, means water. This comprised all

things in affiliation with water.

The term “Hydraulics” means the transmission and control of forces and movement by

means of fluid.

The field of hydromechanics (fluid mechanics) is broken down as follows:

a. HYDROSTATICS:

It is the mechanics of still fluid.

Ex.: Transfer of force in hydraulics.

b. HYDRO DYNAMICS:

It is the mechanics of moving fluid.

Ex.: Conversion of flow energy in turbines in Hydro Electric power plants.

1.2 SPECIAL CHARACTERISTICS OF HYDRAULICS:

High forces with compact size, i.e. high power density.

Automatic force adoption.

2

Movement from standstill possible under full load.

Step less change (control or regulation) of speed, torque, stroke force etc.

Simple overload protection.

Suitable for controlling fast movement process and for extremely slow precision

movements.

Relatively simple accumulation of energy by means of gas.

Combined with decentralized transforming of the hydraulic energy back into mechanical

energy, simplified central drive systems are possible giving a high degree of economy.

1.3 FLUID POWER

1.3.1 WHAT IS FLUID POWER?

Fluid power is energy transmitted and controlled by means of a pressurized fluid,

either liquid or gas. The term fluid power applies to both hydraulics and pneumatics. Hydraulics

uses pressurized liquid, for example, oil or water; pneumatics uses compressed air or other

neutral gases.

Fluid power is a term which was created to include the generation, control and

application of smooth, effective power of pumped are compressed fluid (either liquids or gases)

when this power is used to provide force and motion to mechanisms.

1.3.2 HOW FLUID POWER WORKS?

Pascal’s laws express the central concept of fluid power: “pressure exerted by a

confined fluid acts undiminished equally in all directions”.

Fig-1.1

3

An input force of pounds (44.8 N) on a 1-sq.inch (6.45cm2) piston develops a pressure of 10

pounds per sq.inch (psi) (68.95 Kpa) through out the container. This pressure will allow a 10

sq.inch piston to support a 100 pounds (444.8N) weight. The forces are proportional to the piston

areas.

1.3.3 ADVANTAGES OF FLUID POWER:

Fluid power systems provide many benefits to users including:

1. MULTIPLICATION AND VARIATION OF FORCE:

Linear or rotary force can be multiplied from a fraction of an ounce to several hundred

tons of output.

2. EASY, ACCURATE CONTROL:

You can start, stop, accelerate, decelerate, reverse or position large forces with greater

accuracy. Analog (infinitely variable) and digital (on/off) control are possible. Instantly

reversible motion (in less than half a revolution) can be achieved.

3. MULTI-FUNCTION CONTROL:

A single hydraulic pump or air compressor can provide power and control for numerous

machines or machine functions when combined with fluid power manifolds and valves.

4. HIGH HORSEPOWER, LOW WEIGHT RATIO:

Pneumatic components are compact and lightweight. You can hold a five horsepower

hydraulic motor in the palm of your hand.

5. LOW SPEED TOQUE:

Unlike electric motors air or hydraulic motors can produce large amounts of torque while

operating at low speeds. Some hydraulic and air motors can maintain torque at zero speed

without overheating.

6. SAFETY IN HAZARDOUS ENVIRONMENTS:

Fluid power can be used in mines, chemical plants, near explosives and in paint

applications because it is inherently spark free and can tolerate high temperatures.

4

1.3.4 FLUID POWER APPLICATIONS:

1. MOBILE:

here fluid power is used to transport, excavate and lift materials as well as control or power

mobile equipment. End use industries include construction, agriculture, marine and the military.

Applications include backhoes, graders, tractors, truck brakes and suspensions, spreaders and

highway maintenance vehicles.

2. INDUSTRIAL:

Here fluid power is used to provide power transmission and motion control for the machines of

industry. End use industries range from plastics working to paper production. Applications

include metalworking equipment, controllers, automated manipulators, materials handling and

assembly equipment.

3. AEROSPACE:

Fluid power is used for both commercial and military aircraft, spacecrafts and related support

equipment. Applications include landing gear, brakes, flight controls, motor controls and cargo

loading equipment.

1.4 BASIC PRINCIPLES:

1.4.1 PASCAL’S LAW:

Pascal’s laws express the central concept of fluid power:”states that the pressure or intensity of

pressure at a point in a static fluid is equal in all directions”.

Where force ‘F’ acts on an enclosed fluid via surface ‘A’, pressure occurs in the

fluid. The pressure is related to the amount of force applied to the surface vertically and the area

of application of force.

P=F/A

Fig 1.2 Explaining Pascal’s law

5

Pressure acts on all sides equally and simultaneously. It is equal at all points. This is valid with

omission of the gravity force, which would have to be added according to the fluid level.

1.4.2 BERNOULLI PRINCIPLE:

Which states, “For the horizontal flow of fluid through a tube, the sum of the pressure and

kinetic energy per unit volume of the fluid is constant”?

The Euler’s equation derived along one streamline is called the “Bernoulli’s equation”.

+ + = constant

(Or)

+ + = + + =constant

Where,

=speed ( )

=gravitational constant ( )

=elevation ( ).

=pressure ( )

=density (kg/m³)

1.4.3 CONTINUITY EQUATION:

The equation based on conversation of mass is called continuity equation. Thus for a

fluid flowing through the pipe at all the cross-section, the quantity of fluid per second is constant.

Where,

=Flow rate in kg/sec.

=Density of fluid in kg/m³

=Average velocity

=Constant.

6

If the fluid is incompressible, then the density remains constant.

Then,

Where,

=Flow rate (

=Area ( )

The constant represents the volume of fluid, which passes through each cross section of the

stream tube unit time.

1.5 ADVANTAGES OF HYDRAULIC SYSTEM:

1.5.1 OVER ELECTRICAL SYSTEM:

The hydraulic engineer can decrease the amount of moving mass, much more

than what an electric engineer can do. In aircraft applications, fluid motors

weigh even less than ½ kg/KW power.

In hydraulic drive, the dependence on the current is only up to the extent of

running motor coupled with the pump. If the electric supply fails then a diesel

engine or hand operated pump can be used unlike in fully electrical drive the

machine becomes idle.

Whenever an electric spark is likely, the hydraulic system can manage quite

easily.

Except solenoids creating linear forces, electrical drives cannot generally create

linear motions on their own. But hydraulic systems, by selecting fluid motors

or hydraulic cylinders, one can create rotary or linear motions, whichever may

be desired.

Wherever vibrations exist, fine electric mechanisms are affected, but the

hydraulic systems are not.

7

Laws that are simpler than those governing electricity govern the subject of oil

hydraulics.

1.5.2 OVER MECHANICAL SYSTEM:

It eliminates the need of complicated linkages, gears, cams and levers.

It consists of parts, which are not subjected to great wear as compared to parts

of mechanical system.

It has flexibility of locating points too easily.

It transmits force rapidly between two points located at great distances.

It guarantees an automatic release of unwanted high pressure in case of

overload so that the system is protected against breakdown.

It is sensitive in operation and gives instantaneous response to any operation.

It eliminates the need of lubrication.

It provides infinitely variable speed control not possible through mechanical

means.

It is more economical than mechanical system.

1.5.3 OVER PNEUMATIC SYSTEM:

It is less complex in construction compared to pneumatic system.

Easier installation of hydraulic system.

Noise free operation compared to pneumatic system.

Low maintenance.

Incompressibility of working fluid in a hydraulic system prevents power loss in

contrast with the compressible fluid of a pneumatic system associated with

considerable losses.

Operating pressures are very high (50-200 bar) compared to pneumatic

pressures (5-8 bar).

Feed control is difficult in pneumatic systems.

More number of components of a pneumatic system makes it complex to

operate.

8

Also lubrication is required in a pneumatic system.

1.6 APPLICATIONS OF HYDRAULICS:

It is divided into 5 sectors as follows:

1.6.1. INDUSTRIAL HYDRAULICS:

Plastic machines

Presses

Heavy machinery

Machine tools

1.6.2. HYDRAULICS IN STEEL WORKS:

Lock gates and dams

Bridge operating equipment

Nuclear power station

Milling machinery turbines

1.6.3. MOBILE HYDRAULICS:

Excavators and cranes

Constructed and agricultural machinery

Automobile construction

1.6.4. HYDRAULICS IN SPECIAL TECHNICAL APPLICATIONS:

Telescopes

Antenna operations

Landing gear control of aircraft

1.6.5. HYDRAULICS OF MARINE APPLICATIONS:

Deck cranes

Bow doors

Bulkhead valves

Naturally this summary does not include all possibilities of application, since the

variety of hydraulically operated machines is too great.

9

1.7 INTRODUCTION TO SPECIAL PURPOSE BORING MACHINE:

When market demand is high and the goods have to be supplied at lower

price, the need for mass production of the components arises. To offset the low level of

production by conventional machine tools, it is essential to develop machines for mass

production of components. The mass production components demand high productivity and

reliability of machine tools. The concept of SPM has been evolved to meet these requirements.

By the advent of SPM’s concept, it has become possible to achieve higher

production rates by cutting down un-productive time to minimum and by performing more

number of operations on a component simultaneously that is not possible on conventional

machine tools.

SPM is an essentially metal cutting machine tool, designed and built to perform a

given sequence of operations on a component to give the required output. They are component

oriented and hence the component forms the basis for their development. The SPM’s are

designed and built against specific requirements of machining on any component ensuring

desired accuracies, output rates and performing maximum operations in one loading. Hence these

machines are component oriented unlike conventional machines which are operations oriented.

1.7.1 ADVANTAGES OF SPM:

SPM offers good number of advantages over conventional machine tools such as:

1. Higher output

2. Greater reliability

3. Low machining cost per piece

4. SPM save floor space and labor cost.

10

Fig-1.3 DIAGRAM OF CONVENTIONAL BORING MACHINE WITHOUT

HYDRAULIC POWER PACK

1.7.2 DISADVANTAGES:

a. Time consumption is high for clamping & decamping the work piece

b. Load variations are occurs

c. Difficult to clamping the work piece on the table

11

FIG – 1.4 DIAGRAM OF SPECIAL PURPOSE TWO WAY BORING MACHINE WITH HYDRAULIC POWER PACK:

1.7.3 ADVANTAGES:

1. It eliminates the human assistance for clamping & decamping of work piece.

2. Time taken is less for clamping & decamping of work piece.

3. Load variations are not occur.

4. Ensure firm grip to the work piece is high.

5. It can be clamped rigidly with less wear, greater accuracy and less noise

12

1.8 INTRODUCTION TO HYDRAULIC POWER PACK (HPP):

Basically hydraulic power pack is a device that converts hydraulic energy into mechanical

energy. The hydraulic power pack is nothing but a movable hydraulic system. It contains all the

basic components that are required for a hydraulic system such as tank, pump, valves etc.

Mobility of hydraulic power pack makes them useful for several purposes where oil

pipelines from a stationary hydraulic system cannot be run. The principle on which power pack

works can be easily implemented at various sections with little or no modifications.

Fig-1.5

13

1.9 WORKING OF HYDRAULIC POWER PACK:

1.9.1 WHEN FORWARD STROKE OF PISTON:

The system consists of a pump in fig a gear pump is shown, it may not be a gear

pump always (vane pump, axial pump, radial pump) an oil tank, a pressure relief valve, a

cylinder and a directional control valve

Fig-1.6

14

During the forward stroke of the piston, the pump which is driven by electric

motor Pumps the oil from the tank along the path “PA” into the Directional control valve .From

here the oil reaches the cylinder. When the load moves outwards, the oil on the other side of the

piston goes along the path “BT” in to the tank. The purpose of the pressure reducing valve is to

by pass excess oil to the tank, when the pressure in the pipe line increases beyond a set value.

1.9.2 WHEN RETURN STROKEOF PISTON:

Fig-1.7

During the backward stroke of the piston, the pump which is driven by electric

motor pumps the oil from the tank along the path “PB” in to directional control valve . From

here the oil reaches the cylinder. During the backward, the spool moves to the left and the oil

15

from the pump flows along the path “PB” in to the cylinder and the load moves inward. The oil

on the other side of the piston goes along the path ‘AT’ to the tank.

1.10 DESCRIPTION OF HYDRAULIC POWER PACK:

The power pack is an integral power supply unit, which basically determines

the working of the control unit.

Fig-1.8 HYDRAULIC POWER PACK

A hydraulic power pack offers a simple method of introducing hydraulic operation to

individual machines, with flexibility of being adaptable to other duties. It consists basically of an

integral electric motor, with associated tank. The pump or motor unit may be mounted on the

tank or separately. Packs are usually available in either horizontal or vertical configuration.

Relief and check valves are normally incorporated on the tank. The basic unit may then

be piped to the cylinders or actuators through a suitable control valve.

Hose assemblies are generally preferred to rigid piping for connecting the power pack to

actuators. With hose assemblies it is simpler to disconnect the power pack from one machine and

transfer it to another.

The hydraulic power packs consist of a reservoir that houses the hydraulic fluid, which is

the working medium. The capacity of the tank may vary accordingly to the requirements. The

reservoir is also equipped with an air breather at the top to maintain the pressure in the tank at

atmospheric pressure and it also filters the oil to 40 microns.

16

1.10.1 COMPONENTS OF HYDRULIC POWER PACK

1. Pump

2. Reservoir/tank

3. Directional control valve

4. Pressure relief valve

5. Check valve

1.10.2 PUMP:

Pump is a device, which converts mechanical force and motion into hydraulic fluid power.

The purpose of a pump in a fluid power is to pressurize the fluid so that work may be performed.

The pump serves to create a fluid flow and to allocate the necessary forces to it as required.

FUNCTIONS OF PUMP:

The liquid can be raised to a higher level by virtue of increase in the potential energy of

the liquid.

There would be an increase in liquid pressure.

Increase in the velocity of liquid by virtue of increase in kinetic energy.

TYPES OF PUMPS:

a) Positive displacement

i. Fixed displacement pump

ii. Variable displacement pump

b) Non- positive displacement

POSITIVE DISPLACEMENT:

Positive displacement pumps displace a known quality of liquid with each revolution of

the pumping elements (i.e., gears, rotors, screws, vanes) positive displacement. Pumps

displace liquid by creating a space between the pumping elements and trapping liquid in

the space. The rotation of the pumping elements then reduces the size of the space and

moves the liquid out of the pump.

17

FIXED DISPLACEMENT PUMP: In this fixed displacement pumps the stroke volume cannot

be changed.

VARIABLE DISPLACEMENT PUMP: In this variable displacement pumps the stroke volume

can be changed.

NON-POSITIVE DISPLACEMENT:

Pumps that discharge liquid in a flow is referred to a non positive displacement

DIFFERENT TYPES OF PUMPS:

Practically all hydraulic pumps fall within three design classification – centrifugal, rotary and

reciprocating. The use of centrifugal pumps in hydraulics is limited.

CENTRIFUGAL PUMPS:

Centrifugal pumps are classified as roto-dynamic type of pumps in which dynamic

pressure is developed. This pressure enables the lifting of liquid from a lower level to a higher

level. The basic principle on which centrifugal pumps work is that when a certain mass of liquid

is made to rotate by an external force, it is thrown away from the axis of rotation and centrifugal

head is impressed which enables it to rise to a higher level.

Fig-1.9 CENTRIFUGAL PUMP

RECIPROCATING PUMPS:

The basic principle of reciprocating pumps is to displace a fluid exerting thrust on it.

These types of pumps are also called as positive displacement pumps. In these liquid is sucked

18

and then is pushed due to thrust exerted on it by moving a member, which results in lifting the

fluid to a desired height. As such the discharge of liquid pumped almost wholly depends on

speed of the pump.

Fig 1.10 RECIPROCATING PUMP

ROTARY PUMPS:

Rotary pumps are self-priming and deliver a constant and smooth flow regardless of

pressure variations. All the rotary pumps have rotating parts, which trap the fluid at the inlet

(suction) port and force it through the discharge port into the system. Gears, screws, lobes and

vanes are commonly used to move the fluid. Rotary pumps are designed with very small

clearance between the rotating parts and stationary parts.

Fig 1.11 ROTARY PUMP

19

VARIABLE VANE PUMP :

Vane pumps operate quite differently from gear and lope type. A rotor with radial

slots is positioned off-center in a housing bore. Vanes that fit closely in rotor slots slide in and

out as the rotor turns.

Vanes are the main ceiling element between the suction and discharge ports and are

usually made of a non metallic composite material.

Vane-type hydraulic pumps generally have circularly or elliptically shaped interior

and flat end plates. (Fig. illustrated below is a vane pump with a circular interior) a slotted rotor

is fixed to a shaft that enters the housing cavity through one of the end plates.

Fig-1.12 VARIABLE VANE PUMP

A number of small rectangle plates or vanes are set into the slots of the rotor. As

the rotor turns , centrifugal forces causes the outer edge of each vane to slide along the surface of

the cavity of the vanes slide in and out of the rotor slots the numerous cavities, formed by the

vanes, the end plates, the housing, and the rotor, enlarge and shrink as the rotor and vane

assembly rotors. An inlet is installed in the housing so fluid may flow in to the cavities as they

enlarge .an outlet port is provided to allow the fluid to flow out of the cavities as they become

small.

20

With this variable pump , the displacement volume can be adjusted at the set maximum

operating pressure .In this case hewer the cam is a circular concentric ring . A spring 2 pushes

the cam into its eccentric outlet position towards the rotor. The maximum eccentricity and thus

the maximum displacement volume can be set by means of the screw 5.The spring force can also

be adjusted by means of the screw 6.there is a tangential adjustment of the cam by means of the

height adjustment screw 4.

The pressure, which builds up due to working resistance, affects the internal

running surface of the cam on the pressure side. This results in a horizontal force component,

which operates towards the spring.

If the pressure force exceeds the set spring force the cam ring moves from

eccentric towards zero position. the eccentricity decreases. the delivery flow adjusts itself to the

level required by the user.

If no fluid is taken by the user and the set pressure is thus reached, the pump

regulates flow to almost zero. Operating pressure is maintained, and only the leakage oil

replaced. Because of this, loss of power and heating of the fluid is kept to a minimum.

1.10.3 RESERVOIR:

Fig-1.13 RESERVOIR

21

A hydraulic system must have a reserve of fluid in addition to that contained in the

pumps, actuators, pipes and other components of the system. This reserve fluid must be readily

available too make up losses of fluid from the system, to make up for compression of fluid under

pressure, and to compensate for the loss of volume as the fluid cools. This extra fluid is

contained in the tank usually called a reservoir

In addition to providing fluid during shortage to system, the reservoir acts as a radiator

for dissipating heat from the fluid and as settling tank where heavy particles of contamination

may settle out of the fluid and remain harmlessly at the bottom until removed by cleaning or

flushing the reservoir. Also the reservoir allows contained air to separate from the fluid.

The inside of the reservoir generally has baffles to prevent excessive sloshing of the fluid which

also helps separating fluid return line and pump suction line. This settling technique helps avoid

contamination and also air to refrain from the system.

TYPES OF RESERVOIRS:

The various reservoirs are broadly classified as

Vented (storage) and

Sealed (pressurized and non-pressurized).

Vented reservoir is more advantageous than sealed reservoir, in that

it can be made smaller for the same fluid volume. Care should be taken to avoid over

filling, since this will reduce the air volume and Produce wider ranges of pressure, during

working.

1.10.4 DIRECTION CONTROL VALVES:

Direction control valves are designed to direct the flow of fluid, at a desired time, to the

point in a fluid power system where it will do work. The driving of a ram back and forth in its

cylinder is an example of a directional valve, same as selector, transfer and control valves. They

are ideal for machine tools, production and material handling equipment, marine auxiliary power

controls, off-highway and heavy construction equipment, and oil field and farm equipment.

22

Fig-1.14 DIRECTION CONTROLE VALVE

Direction control valves may be operated by difference in pressure acting on opposite sides of

the valve element, or they may be positioned manually, mechanically or electrically. Often two

or more methods of operating the same valve will be used in different phases of its action.

1.10.5 PRESSURE CONTROL VALVES:

Pressure control valves are used to control and regulate pressure in fluid power systems.

The maintenance or lowering of pressure can be achieved in a number of ways. Some valves are

designed to blow off pressure when a set level is reached, other times they are designed with

flanged ends to allow for ease of maintenance. Normally the valves are smaller than the line in

which it is attached. The design feature prevents the valve from throttling, which would cause

the seat to wear too quickly. The disc is moved by a pneumatic, hydraulic, electrical or manual

operator actuation.

23

In hydraulic systems pressure regulators are used to unload the system and

to maintain and regulate pressure at the desired values. When the system pressure decreases a

certain amount, the regulator will open, sending the fluid to the system. When the system

pressure increases sufficiently, the regulator will close, allowing the fluid from the pump to flow

through the regulator and back to the reservoir. The pressure regulator takes the load off the

pump and regulates system pressure.

1.10.6. CHECK VALVE:

Non-return valves or check valves are used in circuits, are combined in the

body of other valves, to provide flow in one direction only. The simplest type is the spring

loaded ball valve, although this has limited suitability for hydraulic services in high pressure

services, especially good sealing is essential and it may be necessary to design the valve with a

resilient seating valve.

Check valves are used in account to eliminate actuator movements (e.g. Cylinder

movement) and to maintain it in a hold position without creeping as might otherwise occur due

to direction valve spool leakage.

Fig No : 1.15

Fig-1.16 Check Valve

24

1.11 DEFINITION OF HYDRAULIC COMPONENTS:

ACTUATOR: A device used to converting hydraulic energy into mechanical energy. It can be a

motor or a cylinder.

BREATHER: A device, which permits air to move in and out of a container or component to

maintain atmospheric pressure.

CIRCUIT: An arrangement of component interconnected to perform a specific function with a

system.

CYLINDER: A device that converts fluid power into linear mechanical force and motion.

CHECK VALVE: A valve, which permits flow of fluid in one direction only.

CRACKING PRESSURE: The pressure at which a pressure actuated valve begins to pass fluid.

DRAIN: A passage or a line, from a hydraulic component that returns leakage fluid

independently, to the reservoir or vented manifold

DIRECTIONAL VALVE: A valve that selectively directs or prevents fluid flow to desired

channel.

DELIVERY: the volume of fluid discharged by pump in a given time, usually expressed in

gallons per minute (gpm).

FILTER: A device used to separate and retain insoluble contaminants from a liquid.

FLOW CONTROL VALVE: A valve that controls the rate of oil flow through the circuit.

FOUR-WAY VALVE: A direction valve showing four flow points.

LINE: A tube pipe or hose that acts as a conductor of hydraulic fluid.

MANIFOLD: A fluid conductor that provides multiple connection ports.

PLUNGER: Cylindrical shaped part that has only one diameter and is used to transmit thrust

through a ram.

POWER PACK: An integral power supply unit usually containing a pump, reservoir, relief valve

and directional control valve.

25

SERVO MECHANISM: A mechanism subjected to the action of controlling device, which will

operate as if it were directly actuated by controlling device.

SOLENOID: An electro mechanical device which converts electrical energy into mechanical

motion, used to actuate direction valves.

SPOOL: A term loosely applied to any moving cylindrically shaped part of a hydraulic

component which moves to direction flow through the component

LAMINAR FLOW: Fluid flow in which particles slide smoothly along lines parallel to the wall.

Resistance to flow is proportional to the square of the velocity.

TURBULENT FLOW: Random local disturbances in the fluid flow pattern about a mean

average velocity. Resistance to flow is proportional to the square of the velocity.

REYNOLDS NUMBER: A dimensionless number relating fluid velocity V, distance as a pipe

diameter D, and fluid velocity.

1.12 HYDRAULIC SYMBOLS

These graphical symbols are as per ISO R/1219 with help of graphical symbols one may be able

to read function and working of a hydraulic circuit.

Line working (main)

Line Pilot (for control)

Line Liquid Drain

Flow Direction

Hydraulic

Line Crossing

Line Joining

Line with fixed Restriction

Flexible line

26

2. LITERATURE SURVEY

The growth of oil hydraulics as a parallel development in transportation, farm and earth moving

equipment, industrial machinery, machine tool ship control, fire control, air craft missiles and

numerous other applications. Oil hydraulics; however forms one aspect of an overall systems

concept.

With the impact of rising costs and global shortages of fossil fuels like coal and

petroleum, the transmission system designers today are forced to critically consider his options

from the point of view of efficiency and overall economy. This has resulted in the introduction of

oil hydraulic machine components over the last decade, with remarkable increase in power

density and operating pressure, with greater overall efficiency. This trend is likely to continue

into the 1990’s with a major break through in materials and manufacturing technology.

In 1980’s we have seen the introduction of organic and synthetic fluids in a hydraulic

system on a very large scale. The coming decade shall also witness the introduction of water

based hydraulic fluids in industrial hydraulics. The problem today is not the development of

water-based fluids themselves, but in the design of hydraulic machine and components, which

use such fluids.

The rising costs and shortages of mineral oil based hydraulic fluid will certainly provide

the incentive to switch over to water based fluids. But in the various problems, which are yet to

be solved water hydraulics did not make any greet impact on industry in early half

1990’s.however any developments or research activities in this sphere will be of pioneering

nature and shall definitely be of great help to the organization engaged in such work.

There has been specific growth in the application of power during the

1960’s&1970’s.today the applications range from the artifices like gigantic machine tools,

injection molding machines, and presses.

These applications are likely to grow proliferate further in the future. During the last two

decades oil hydraulics has made great advances in the field of farm tractor, farm machinery and

implements. With the world facing the challenge of feeding and ever-increasing population, there

is bound to be phenomenal growth in farm mechanization.

27

3. DESIGN CALCULATIONS

3.1 Factors affecting design of hydraulic circuits:

Space available: the available physical space within which a hydraulic cylinder or a fluid must

be accommodated may dictate the size of the cylinder or the fluid motor.

Force required: once the piston size is decided, the force required at the actuator depends on the

working pressure of the system. High the working pressure, lower is the size and weight of the

actuator, for the same force. But it results in many disadvantages.

Flow required: the speed of the actuator determines the flow capacity of the pump. Once the

flow capacity of the pump and the power of the systems working pressures are known, the power

of the prime mover can be easily be calculated. Thereby the size of the reservoir, the suction

strainer, the pipelines and all other valves are determined.

Environmental conditions: this determines whether the system should have ordinary or fire

proof hydraulic fluid in hazards condition, shock resistance on mobile use, non magnetic

construction in certain application, noise elimination arrangement in noisy atmosphere, more

filtration arrangement in a dusty atmosphere and some special design mountings or fittings in

typical applications etc.

Sophistication required: the need of the sophisticated controls in the circuit depends on how

much accuracy and automation are required in the desired motion.

Economic considerations: this is the most important factor which must be kept in mind while

designing hydraulic circuit. If a hydraulic machine is likely to operate 24 hours a day, the life

expectancy of each component becomes an important consideration. The need of frequent

replacement of components will create maintenance problems and production losses. If a

hydraulic machine is likely to operate in a place where trained personal are not available, any

sophistication in the hydraulic circuit has to be avoided.

28

3.2 DESIGN CALCULATIONS

3.2.1 CALCULATIONS FOR PUMP SIZE:

(1)Considering the component stopper and rough guide for 2 cylinder and 3 cylinder

component (LH):

Flow rate of fluid,

= (/4) (25) ² (25)

= 12271.84

=12271.84 (60)

=0.736 -----3.1

(2)Considering the component stopper and rough guide for4 cylinder component (LH):

= (/4) (25) ² (25)

= 12271.84

=12271.84 (60)

=0.736 ------3.2

(3) Considering the component stopper and rough guide for 3 cylinder and 4 cylinder

component (RH):

= (/4) (25) ² (25)

29

= 12271.84

=12271.84 (60)

=0.736 -------3.3

(4)Considering platform Lifting:

= (/4) (40) ² (25)

=31400

=31400 (60)

=1.884 ------3.4

(5) considering Rectangular component stopper (rest pads):

= (/4) (25) ² (25)

= 12271.84

=12271.84 (60)

=0.736

But there are 3 cylinders. Therefore flow rate for 3 cylinders is given by =0.736

3=2.208 ---------3.5

30

(6) Considering lifting platform clamping:

= (/4) (25) ² (25)

= 12271.84

=12271.84 (60)

=0.73

But there are 4 cylinders. Therefore flow rate for 4such cylinders is given by

=0.736*4=2.994 -------3.6

(7)Considering component clamping

= (/4) (63) ² (25)

= 77931.13

=77931.13 (60)

=4.675 --------3.7

(8) Considering operation plunger for crank axis for rotary guide bush in fixture:

= (/4) (20) ² (25)

= 7850

31

=7850 (60)

=0.471

But there are 2 such cylinders. Therefore flow rate for 2 such cylinders is given by

=0.471 2=0.942 ----------3.8

(9) Considering operation plunger for cam axis for rotary guide bush in fixture:

= (/4) (20) ² (25)

= 7850

=7850 (60)

=0.471

But there are 2 such cylinders. Therefore flow rate for 2 such cylinders is given by

=0.471*2=0.942 --------3.9

(10) Considering the spindle orientation plunger (LH):

Flow rate

= (/4) (40) ² (25)

= 31400

32

=31400 (60)

=1.884 ------------3.10

(11) Considering the spindle orientation plunger (RH):

Flow rate

= (/4) (40) ² (25)

= 31400

=31400 (60)

=1.884 ----------3.11

(12) Considering component ejector:

Flow rate

= (/4) (40) ² (25)

= 31400

=31400 (60)

=1.884 -----------3.12

33

Pump to be selected should be able to supply fluid at a flow rate required at a

given time, by different cylinders working together at a given time i.e., the pump flow is taken as

the maximum of (3.1), (3.2), (3.3), (3.4) ,(3.5) , (3.6) ,(3.7), (3.8), (3.9), (3.10),(3.11), and

(3.12) .

For better result it is taken as 120% of the maximum value.

=1.2 4.675

=5.61

The standard value of pump that is available and selected has the flow rate of “10 ”.

3.2.2 CALCULATION FOR POWER OF ELECTRICAL MOTOR:

(Pump flow) (Working pressure)

Power (in ) = --------------------------------------------------

(600) (Geometric efficiency, )

Where

Pump flow is in “ ”

Working pressure is in “ ”

Geometric efficiency=0.8(assumed)

Power (in ) = (10 30)/ (600 0.8)

=0.625

Therefore the power of electric motor is 0.625

34

3.2.3 CALCULATION OF TANK CAPACITY REQUIRED:

To provide uninterrupted supply of hydraulic fluid and to prevent vacuum inside, the tank

capacity is taken as:

C =2 to 2.5 times the pump capacity

=2 to 2.5 (10 )

=20 to 25

The standard size of tank that is available is “25 .”

3.2.4 CALCULATION OF RELATIVE PRESSURE LOSSES IN CONNECTED TO

DIFFERENT CYLINDERS:

(A) (a) Related to component stopper and rough guide for 2 cylinder and 3 cylinder

component (LH):

Reynolds number

Where,

= Velocity of the fluid through pipe in “ ”

= 3000 .(assumed)

=Viscosity of the fluid in “ ”

=68 .

= Inner diameter of the pipe 12x1 ( )

=10 .

35

= Inner diameter of pipe 6x1 ( )

=4

Therefore

= (3000) (10)/68.

=441.7(which is less than 2300, so flow is laminar)

Pipe friction coefficient for laminar flow is

= 64/441.7

= 0.145

Pressure loss in pipe, connected to the cylinder

Where, =pressure loss in pipe

= Pipe friction coefficient

=Length of pipe 12x1 ( )

=5 ( )

= Length of pipe 6x1 ( )

=1.5( )

=Flow speed in the line ( )

=3 ( )

= Density of Oil

= 0.89

36

Therefore,

= (0.145 5 0.89 3² 10)/ (2 10)

=2.90 ------------------------------------------ (1)

(b)

= (3000 4)/68

=176.47(<2300)

=64/176.47

=0.362

= (0.362 1.5 0.89 3² 10)/ (2 4)

=5.43 ---------------------- (2)

By adding (1) & (2), we get the total pressure loss in the pipe.

i.e., =2.90 + 5.43 =8.33

(B) (a) Related to component stopper and rough guide for 4 cylinder component (LH):

Reynolds number

= (3000) (10)/68

=441.7(<2300)

37

Pipe friction coefficient for laminar flow is .

=64/441.7

=0.145.

Pressure loss in the pipe, connected to the cylinder

= (0.145 5 0.89 3² 10)/ (2 10)

=2.90 ----------------- (1).

(b)

= (3000*4)/68

=176.47 (<2300)

= 64/176.47

=0.362

=0.362 1.5 0.89 3² 10)/ (2 4)

= 5.43 ---------------- (2)

38

By adding (1) & (2), we get the total pressure loss in the pipe.

=2.90+5.43=8.33

(C) (a) Related to component stopper and rough guide for 3 cylinder and 4 cylinder

component (RH):

Reynolds number,

= (3000) (10)/68.

=441.7(< 2300)

Pipe friction coefficient for laminar flow is

=64/441.7

=0.145

Pressure loss in pipe, connected to the cylinder,

= (0.145 5 0.89 3² 10)/ (2 10)

=2.90 ----------------------------- (1)

(b)

= (3000 4)/68

=176.47(<2300)

=64/176.47

39

=0.362

= (0.362 1.5 0.89 3² 10)/ (2 4)

=5.43 ---------------------- (2)

By adding (1) & (2), we get the total pressure loss in the pipe.

i.e., =2.90+ 5.43 =8.33

(D) For platform lifting:

= (3000 10)/68

=441.7(<2300)

=64/441.7

=0.145

= (0.145 0.89 2 3² 10)/ (2 10)

=1.16

40

(E) (a) For retractable component stopper:

Reynolds number /Re dV

= (3000) (10)/68.

=441.7(< 2300)

Pipe friction coefficient for laminar flow is

=64/441.7

=0.145

Pressure loss in pipe, connected to the cylinder

= (0.145 0.89 2 3² 10)/ (2 10)

=1.16 ------------------- (1)

(b) /Re dV

= (3000 4)/68

=176.47(<2300)

=64/176.47

=0.362

41

= (0.362 1.5 0.89 3² 10)/ (2 4)

=5.43 ---------------------- (2)

By adding (1) & (2), we get the total pressure loss in the pipe.

i.e., =1.16+ 5.43 =6.59

(F) (a) For lifting platform clamping:

Reynolds number /Re dV

= (3000) (10)/68.

=441.7(< 2300)

Pipe friction coefficient for laminar flow is

=64/441.7

=0.145

Pressure loss in pipe, connected to the cylinder

= (0.145 0.89 2 3² 10)/ (2 10)

= 1.16 --------------------- (1)

(b) /Re dV

42

= (3000*4)/68

= 176.47(<2300)

=64/176.47

=0.362

= (0.362 1.5 0.89 3² 10)/ (2 4)

=5.43 ---------------------- (2)

By adding (1) & (2), we get the total pressure loss in the pipe.

i.e., =1.16+ 5.43 =6.59

(G) Component clamping:

Reynolds number /Re dV

= (3000) (10)/68.

=441.7(< 2300)

Pipe friction coefficient for laminar flow is

=64/441.7

=0.145

43

Pressure loss in pipe, connected to the cylinder

= (0.145 0.89 2 3² 10)/ (2 10)

=1.16 --------------------- (1)

(H) For operation plunger for crank axis for rotary guide bush in fixture:

Reynolds number /Re dV

= (3000) (10)/68.

=441.7(< 2300)

Pipe friction coefficient for laminar flow is

= 64/441.7

=0.145

Pressure loss in pipe, connected to the cylinder

= (0.145 0.89 3 3² 10)/ (2 10)

=1.74 --------------------- (1)

(I) for operation plunger for cam axis for rotary guide bush in fixture:

Reynolds number /Re dV

= (3000) (10)/68.

=441.7(< 2300)

44

Pipe friction coefficient for laminar flow is

=64/441.7

=0.145

Pressure loss in pipe, connected to the cylinder

= (0.145 0.89 3 3² 10)/ (2 10)

=1.74 --------------------- (1)

(J) For spindle operation plunger (LH):

Reynolds number /Re dV

= (3000) (10)/68.

=441.7(< 2300)

Pipe friction coefficient for laminar flow is

=64/441.7

=0.145

Pressure loss in pipe, connected to the cylinder

= (0.145 0.89 5 3² 10)/ (2 10)

=2.90 --------------------- (1)

45

(K) For spindle operation plunger (RH):

Reynolds number /Re dV

= (3000) (10)/68.

=441.7(< 2300)

Pipe friction coefficient for laminar flow is

=64/441.7

=0.145

Pressure loss in pipe, connected to the cylinder

= (0.145 0.89 5 3² 10)/ (2 10)

=2.90 --------------------- (1)

3.2.5 CALCULATION OF TOTAL PRESSURE LOSS IN THE SYSTEM:

Loss through the pipe lines = Maximum of the values

=8.33 .

There are two such lines of pipe connected to cylinder. So, Maximum loss in pipe lines is given

by:

=2 8.33

=16.66

46

There are 16 valves having four ways each. So, considering that the pressure loss through each

way is 1 bar (assumed), for 16 such valves, we have,

Pressure loss = (no. of valves) (no. of ways) (pressure loss)

= (16) (4) (1)

=64

Therefore the total pressure loss in the system is

=64 bar + 16.66 bar

=80.66

(Total pressure loss ( ) (total discharge ( ))

Power loss due = ------------------------------------------------------------

to pressure loss

Total discharge in the pipe lines

= (0.73+0.73+0.73+1.88+2.19+2.92+4.67+1.88+0.942+0.942+1.88+1.88)

=21.37

Therefore power loss = (80.66 10, 5) (21.37 10, 3)/0.8

=3576.35

= 3576.35/746

= 4.79

But 1 =641.2

Therefore 4.79 = 4.79 641.2

47

= 3073.9

Cooler to be selected should be able to dissipate this heat, resulted from pressure drop

and hence from power loss. The standard cooler near to this capacity available is of 3000

, and it is selected.

48

4. SLECTION PROCEDURE

4.1 SLECTION PROCEDURE

4.1.1 PUMP :

Pump selection depends upon factors such as :

1. Working pressure

2. Duty

3. Maximum power rating (max delivery, speed rating)

4. Efficiency

5. Control

6. Weight

7. Fluid

8. Noise

9. Cost

10. Maintenance

EFFICIENCY:

Where there is considerable variation in demand it is usually more efficient as

regards both operating and running costs, to use a variable delivery pump, although the initial

cost is high.

Efficiency may be important (ex: where large volumes of fluids are being

pumped) or relatively insignificant (ex: in a light duty system where ample input power is

available from an inexpensive drive, or an over size pump is to be used for a particular reason).

49

SPEED:

Pump speed, governs the actual delivery operating speed limits are set by the design of

the pump, while desirable running speeds are set by the normal running speed of the driver.

NOISE:

Noise generated in the pump is largely result of sudden pressure change between suction

and outlet side, thus pumps which produces high localized pressures are likely to be nosier than

those providing a more gradual pressure change.

COST:

Probably in majority of application the initial cost is secondary importance, to

performance and other factors. Pump cost, therefore becomes a major factor for selection after all

other requirements have been met.

Despite of the many factors to be considered in the selection of the pump, in this case

the important factors, which were considered are the flow rate, comparatively least cost, variable

delivery requirements, noise. So a variable displacement vane pump (with a flow rate of 10

) was selected for use

4.1.2 TANK:

The tank capacity should be 2.5 times the flow rate of the pump as such

rectangular steel tank with 25 size and mounting seat is selected.

Features of selected reservoir:

1. Large hole for cleaning purposes

2. Sloping tank base

3. Sand blasted and base coated with zinc paint inside and outside

50

4. Suitable for internal excess pressure up to 0.5 bar

5. Oil drains screw on tank base.

4.1.3 CHECK VALVES:

Features:

1. 7 sizes-flows to270

2. Maximum working pressure-200

3. Choice of cracking pressure 0.35 /3.5

4. Steel poppet type construction

5. Prevents flow in reverse direction

6. Not recommended for use to check reverse flow resulting in shock conditions

The check valve which acts as a non return valve not allowing fluid to flow back,

is selected on the basis of pipe size connecting to the check valve in the main line which is ¼”

and on the basis of flow rate in the main line which is 10 , for having free flow with no

instruction check valve with flow rate more than this is used i.e., modelCUT-02-5

4.1.4 BREATHER:

Fig-4.1

51

Features:

1. Chrome plated steel cap-vents underneath

2. Filtration 40 microns standard/optional 40 microns

3. Air flows to 25 cfm (750lpm) rugged cast aluminum housing

4. Metal strainer

5. Hard ware includes gasket

As through this unit the fluid is poured into the tank, the breather selected should

acts as a filter to strain unwanted material in fluid to enter in to the tank as well it should act as a

bleed filter, where the air entering (during breathing) is also filtered and large particles of dust is

restrained. So a breather with a max. Micron rating and flow rate is selected to have free flow of

fluid and air (during breathing)

4.1.5 OIL LEVEL GAUGE:

Features:

1. Sizes 3”, 5”&10” bolt centers

2. For non pressurized tanks only

3. Can be mounted on tapped holes

4. Suitable for mineral/petroleum based oils

5. Max temperature of 80 C

Selection of a level gauge is made to depending on the height of the tank/reservoir. In this case

the tank model is selected prompts to use an oil level gauge of dimension 127 mm. so the

available LG-05 model is selected

52

Fig-4.2

4.1.6 SUCTION STRAINER:

Fig-4.3

Features:

1. Reusable SS 100 mesh/149 microns st.

2. Aluminum die cast nut

3. Steel cap/support tube

4. Continuous epoxy bond

53

5. Max working temperature 80 C

6. Suitable for hydraulic /mineral oil

Selection of strainer is done as such the flow rate through the strainer is taken

as 3 times through flow rate of the pump selected (standard). The flow rate of pump selected is

10 and so the flow rate through the suction strainer should be around 30 ModelSC#010

with flow rate 40 is selected. As the strainer is considered as coarse filter a wire mesh filter

element is used.

4.1.7 RETURN LINE FILTER

Features:

1. Direct tank mounting

2. 10 bar working pressure

3. Max. Temperature 80 C

4. All aluminum die casting construction

5. 4-sizes flow to 175

6. By pass standard 1 bar

7. Elements replaceable through cover

8. Suitable for mineral/petroleum based oils

The return line filter is selected on the basis of pipe connected to it and the filtration requirement.

The pipe connected to this filter in the return line is of the size ¾”, so model TIF2-06 is selected.

54

Fig-4.4

4.2 DESCRIPTION OF HYDRAULIC POWER PACK CIRCUIT

A variable displacement vane pump, pumps the fluid from hydraulic tank to a system connected

(here a control unit for the purpose of clamping).a suction strainer is used to filter the fluid and

the retaining capacity of a strainer is 149 microns.

The pump is driven by a electric motor having a power of 1 HP and running at 1500rpm is

used .the fluid from the suction line is raised to a pressure of 30kg/cm2 and a flow rate of

10lpm .the pump is connected to the electric motor with flexible coupling.

The reservoir is provided with an air breather which maintains the oil inside the tank at

atmospheric pressure. The oil breather is also used to fill the oil in the reservoir. The air breather

has a retaining capacity of 40 microns.

The reservoir is also provided with an oil level gauge which indicates the level of oil in tank. The

pressure available in the pressure line can be read by the pressure gauge with the help of pressure

gauge isolator.

55

The fluid from the pressure line is allowed to flow only in one direction with the help of check

valve which allows the fluid to flow in only one direction.

The hot fluid inside the pump is cooled by passing the oil to an air to oil cooler.

The fluid from the control unit after its function returns to the reservoir through the return line T.

The fluid from the return line passes to the reservoir through a return line filter having a capacity

of 25 microns. If the return line filter gets clogged the fluid returns back to the reservoir through

a by pass valve.

The reservoir is also provided with a baffle plate at the bottom to separate the fluid coming from

the return line from the fluid, which has to be pumped in the pressure line. it avoids the foam

formed in the fluid from return line top enter in the fluid being pumped in to the pressure line, a

baffle plate provides the obstruction, so that the fluid has to cross the baffle plate to the other

side. The oil level which stops the function of the power pack if the level of oil in the reservoir

drops below the required level.

4.2.1 CONTROL CIRCUITS DESCRIPTION

Component stopper and rough guide for 2 cylinder and 3 cylinder component from the suction

line the oil is forced into the pressure line through the pump at 35 bar and a solenoid valve which

contains the flow until the set pressure builds up in the system. Once the pressure is built up the

fluid in the pipeline ‘p’ reaches the cylinder through solenoid valve. The pressurized fluid in line

‘p’ which reaches the cylinder pushes the plunger in downward direction. This is the initial

position of the cylinder before any operation. The component can be rough guided and stopped

by moving the cylinder from down ward to upward direction this can be done by energizing the

solenoid valve. By activating the solenoid valve, the fluid from p to a is connected to p to b and

the fluid lifts the plunger in upward direction. As a result by actuating solenoid valve hydraulic

energy is converted into mechanical energy. And now the cylinder is used as a component

stopper.

56

The same mechanism is used for 3 cylinder and 4 cylinder component stopper,

platform Lifting And Clamping, Component Clamping, Component Ejector, Spindle Orientation

Plunger Etc.

A. COMPONENT TRANSFER:

From the suction line oil is forced in to the pressure line through the pump at 35

bar and a solenoid valve which contains the flow until the set pressure builds up in the

system. Once the pressure is built up the fluid moves to the hydraulic motor present at the

fixture. The hydraulic energy given by the pump at the reservoir is converted back to

mechanical energy by the hydraulic motor. According to the direction of the energizing of

the solenoid valve at the fixture the linear movement to vices is controlled. The rotary motion

of the hydraulic motor is transferred to the vice as linear motion by the lead screw. Once the

fixture holds the work piece the fluid is drained off from the motor resulting in no work

being done and causing the vice to remain stationary. When the solenoid valve is energized

in reverse direction the motor changes its direction of rotation and then causes the withdrawal

of the vice.

in this way the hydraulic energy is converted into mechanical energy for

transferring of the component by hydraulic motor and lead screw mechanism.

57

4.3 HYDRAULIC CRICUITS

58

4.4 BILL OF MATERIALS

ITEM QTY DESCRIPTION SPECIFICATION MAKE

01 1 HYD.TANK 25 LTS DHIL

02 1 OIL LEVEL GAUGE LG2-5 HYDROLINE

03 1 FILLER BREATHER FSB-25 HYDROLINE

04 1 SUCTION STRAINER IND-STR-20G VICKERS

05 1 RETURN LINE FILTER RLF-06-10-VI HYDAX

06 1 FILTER ELEMENT CRLF-06-10 HYDAX

07 1 AIR TO OIL COOLER SP-AOC-009 SANTOSH

08 1 ELECTRIC MOTOR 2HP, 1500RPM ABB/CGL

09 1 FLEXIBLE COUPLING L-095 LOVEJOY

10 1 HYD.VANE PUMP PVB-5-FRSY-20 VICKERS

11 1 PR.GAUGE ISOLATOR SINGLE STN. FENNAR

12 1 PRESSURE GAUGE 0-100Kg/cm² MASS

13 1 AIR BLEED VALVE ABS-03-10-IN80 VICKERS

14 1 IN LINE CHECK VALVE DT8P1-06-5-11 VICKERS

15 1 PULSATING DAMPER ¼”PT X BSP 3/8” REPUTED

16 1 INLINE CHECK VALVE DTP8P1-06-30-11 VICKERS

17 1 INLINE CHECK VALVE DTP8P1-06-30-10 VICKERS

18 1 DRAIN BALL VALVE BSP ½” SHREEM

20 9 DIRECTION VALVE DG4V-3S-2N-U205-60 VICKERS

21 2 DIRECTION VALVE DG4V-3S-2A-U205-60 VICKERS

22 2 NON RETURN VALVE RHD 12 PL PACKER

23 1 FLOW CONTROL VALVE DGMFN-3-Y-A2 VICKERS

24 5 DIRECTION VALVE DG4V-3S-6C-U205-16 VICKERS

27 1 FLOW CONTROL VALVE DGMFN-3-X-A2W-V2W VICKERS

28 1 PR. REDUCING VALVE DGMX1-3-PW-AW-20 VICKERS

29 2 PR. SWITCH 1 PS 14/50 POLYHDRON

31 1 PR.GAUGE ISOLATOR SINGLE STATION FENNAR

32 1 PRESSURE GAUGE 1-01,A55-G1/4 FIEBIG

38 11 ORIFICE Ø8,9X8 HMT

59

5. HYDRAULIC FLUIDS:

5.1 DESIRABLE PROPERTIES OF HYDRAULIC FLUIDS:

5.1.1 VISCOSITY AND VISCOSITY INDEX:

Viscosity of a hydraulic fluid plays a vital role and it should represent a balance between

requirements of power transmission and those of lubrication and sealing. An oil of lower viscosity may

efficiently transmit power may create problem of wear of components which are subjected to boundary

lubrication condition has exists in vane type and in gear type pump. It may also fail to provide effective

sealing, thereby increases chances of leakage.

5.1.2 SELECTION OF VISCOSITY:

a) It is decided on the basis of lowest viscosity necessary for a typical application. Mostly

recommended value is 65 centistokes at 37.8 c.

b) Based on operating temperatures and pressures.

c) To some extent it also depends on type of pump employed in the system.

For normal purpose the oil must have 20.5 centistokes running at 1800rpm, 16

centistokes for 1200rpm pumps. Best viscosity ranges for both 1200-1800rpm pumps would be 25.5

centistokes to 54 centistokes.

5.1.3 OXIDATION STABILITY:

Hydraulic oils while transmitting power are subjected to oxidation due to heating and agitation in

presence of air and metallic catalysts, which are present in the system. It is not feasible to completely

eliminate oxidation although it can be controlled to some extent with the use of proper quality base oils

and antioxidant additives.

Oil on oxidation forms soluble and insoluble degradation products, which tends to

increase the viscosity of oil. Some oxidation products may get deposited on critical components in the

form of sludge, thus impairing the efficiency of the mechanism.

60

5.1.4 ANTICORROSIVE PROPERTY:

Antioxidant oils show anticorrosive property also, because the oils remain free from acids,

which are products of oxidation. But in the presence of moisture and air, rusting of ferrous components

may take place.

5.1.5 COMPRESSIBILITY:

Important requirements of hydraulic oils especially in high pressure applications are

that these should be least compressible.

This property affects the smoothness of operation so designer takes necessary care at the time of

designing the system in this respect. Entrained air in oil as an adverse effect on compressibility and it

should be minimized. The entrained air can also cause cavitations.

5.1.6 DEMULSIBILITY PROPERTY:

Ability to separate readily from water is also an important requirement. Stable emulsions

damage the equipment since they hold in suspension dirt and wear particles and consequently effect the

efficiently functioning of the system.

5.1.7 POUR POINT:

This temperature although not critical from the point of view of operation, has an influence on storage

and low temperature starting ability. Pour point is preferably kept at the lowest depending on the

application. The general practice is to keep it 10 c below the lowest anticipated operating temperature. If

necessary pour point depressant additives are added to obtain the desired level of pour point.

5.1.8 FIRE HAZARDS:

Fire resistant fluids are employed where working temperatures are excessively high or the equipment is

used in the vicinity of furnaces, die casting machines, forging presses, moulding machines, melting pots,

and welding torches etc. for such applications special oils normally of non petroleum origin are

employed.

61

5.1.9 DIFFERENT FLUIDS USED IN HYDRAULICS:

Water

Mineral oil

Organic oil

Synthetic oil

Water was one of the most widely used hydraulic fluids in early hydraulic machinery. It

has the advantages of being inexpensive, readily available. Its disadvantages are that it is a poor

lubricant, is corrosive to steel and iron, and cannot be used below 0o C unless additives are

added. In spite of its disadvantages, it is still used in large central hydraulic pressure systems

such as rubber plants and plastic molding plants.

Mineral oil has displaced water as a hydraulic fluid in hydraulic machinery. Mineral oil is

a good lubricant. These oils can also be used at sub zero temperatures. Mineral oil has the

disadvantage of poor temperature-viscosity characteristics. Various additives have been included

in mineral oils to improve their viscosity characteristics.

Organic oils are widely used as hydraulic fluids, especially in automobile brakes. This

has been brought about by the use of natural rubber for lines and packing. Organic oils do not

affect natural rubber. These oils are also used with additives.

In recent years, synthetic oils notably, silicon oil is used for hydraulic service. They are excellent

for this use but cost more than mineral oils. Their advantages lie in their freedom from sludge

forming components and they have very flat viscosity characteristics.

5.2 FLUID ANALYSIS BY USING ANSYS:

5.2.1 INTRODUCTION TO ANSYS:

The ANSYS computer program is a large-scale multi-purpose finite element

program, which may be used for solving several classes of engineering analyses. The analysis

capabilities of ANSYS include the ability to solve static and dynamic structural analysis, study –state

62

and transient heat transfer problems, mode-frequency and bulking, eigen value problems, static or

time-varying magnetic analysis and various types of field and coupled-field applications. The

program contains many special features, which allow non-linearities and secondary effects to be

included in the solution, such as plasticity, large strain, hyper elasticity, creep, swelling, large

deflections, contact, stress stiffening, temperature dependency, material anisotropy and radiation.

ANSYS has been developed, other special capabilities, such as sub-structuring, sub modeling,

random vibrations, kinetostatics, kinetodynamics, free convection fluid analysis, acoustics, magnetic,

piezoelectric, coupled –field analysis and design optimization have been added to the program. These

capabilities contribute further to making ANSYS a multi-purpose analysis tool varied engineering

disciplines

The ANSYS program has been in commercial use since 1970,and has been used

extensively in the aerospace, automotive, construction, electronic energy services, manufacturing,

nuclear, plastics, oil and steel industries. In addition, many consulting firms and hundreds of

universities use ANSYS for analysis, research and educational uses. ANSYS is recognized world

wide as one of the most widely used and capable programs of its type.

The ANSYS element library contains more than 60 elements for static and

dynamic analyses, over twenty for heat transfer analyses, and includes numerous magnetic, field and

special purpose elements. This variety of elements allows the ANSYS program to analyze 2-D and3-

D frame structures, piping systems, 2-D plane and axis symmetric solids, 3-D solids, flat plates, axis

symmetric and 3-D shells and non-linear problems including contact (interfaces) and cables.

The input data for an ANSYS analysis are prepared using a pre processor. The

general pre processor (PREP7) contains powerful solid modeling and mesh generations capabilities

and is also used to define all other analysis data.(geometric properties( real constants) ,material

properties, constraints, loads etc..,) , with the benefit of the data base definition and manipulation of

analysis data. Parametric input, user files, macros and extensive online documentation are also

available, providing more tools and flexibility for the analyst to define the problem. Extensive

graphics capability is available throughout the ANSYS program, including isometric, perspective,

63

section, edge and hidden line displays and 3-D structures, x-y graphs of input quantities and

results of counter displays of solution results. A graphical user interface is available throughout

the program, to guide new users through the learning process and provide more experienced

users with multiple windows, pull-down menus, dialogue boxes, tool bar and online

documentation.

The analysis results are reviewed using post processor, which have the ability to

display distorted geometries, stress and strain contours, flow fields, safety factor contours, contours

of potential field results (thermal, electric, magnetic) vector field displays mode shapes and time

history graphs .The postprocessors can also be used for algebraic operations, database manipulations,

differentiation and integration of calculated results. Root-sum –square operations may be performed

on seismic modal results. Response spectra may be generated from dynamic analysis results. Results

from various loading modes may be combined for harmonically loaded ax symmetric structures.

5.2.2 TERMS COMMONLY USED IN ANSYS:

DESCRITIZATION: The process of selecting only a certain number of discrete points in the body

can be termed as Discrimination.

CONTINUUM: The continuum is the physical body, structure solid being analyzed.

NODE: The finite elements, which are interconnected at joints, are called nodes or nodal points.

ELEMENTS: Small geometrical regular figures are called elements

DISPLACE MODELS: The simple functions, which are assumed to approximate the displacement

for each element. These functions are called the displacement models or displacement functions.

LOCAL COORDINATE SYSTEM: Local coordinate system is a one that is defined for a particular

element and not necessary for the entire body or structure.

64

GLOBAL SYSTEM: The coordinate system for the entire body is called the global coordinate

system. NATURAL COORDINATE SYSTEM: Natural coordinate system is a local system, which

permits the specification of a point within the element by a set of dimensionless numbers. Whose

magnitude never exceeds unity.

INTERPOLATION FUNCTION: It is a function, which has a unit value at one nodal point and a

zero value at all other nodal points.

ASPECT RATIO: The aspect ratio describes the shapes of the element in the assemblage for two

dimensional elements, this parameter is defined as the ratio of largest dimension of the element to the

smallest dimension.

FIELD VARIABLES: The principle unknowns of a problem are called the variables.

Fig-5.1 ABOVE FIG REPRESENT STRESSES INDUCED ON THE CYLINDER THE

FLUID TAKEN AS MINERAL OIL

65

Fig-5.2 ABOVE FIG REPRESENT STRESSES INDUCED ON THE CYLINDER THE

FLUID TAKEN AS WATER GLYCOLS

66

6. RESULTS

After designing and selecting the required parts of the Hydraulic Power Pack including

calculations of power requirements of motor and pump, it was found that the Hydraulic

clamping system is more efficient and economical compared to Mechanical clamping system

comprising of various levers, screws, cams etc. which are prone to overloading prevalent in

many component clamping units.

We also recognized the necessity of a Hydraulic Power Pack in a SPECIAL PURPOSE

BORING MACHINE, as the component can be clamped rigidly with less wear, smooth

running, greater accuracy and less noise. So, a Hydraulic system is more effective and

efficient as compared to a Mechanical system.

67

7. CONCLUSIONS

By employing a hydraulic system the advantage that can be utilized as compared

to the mechanical and electrical systems are:

1) Possibility of automation of all type of movements.

2) Speeds, forces can be easily and effectively controlled by using cylinders, and linear

movements can be carried out without the use of mechanical components.

3) Eliminates the need of lubrication system because of the presence of self-lubricating system.

4) Eliminates the need of complicated Linkages ,Gears ,Cams and Levers due to which friction

losses can be reduced when compared to mechanical and electrical systems.

68

8. BIBLIOGRAPHY

Slno Authors Book Description Publishers Issued on

1 A.Schmitt THE HYDRAULIC TRAINERG.L. Rexroth

GmbH-

2 VickersINDUSTRIAL HYDRAULICS

MANALVickers 1989

3P.K. Mukherjee &

S. Ilango

BASICS OF HYDRAULIC

CIRCUITS

FLOWLINES

ENGINEERING1996

4Dr. P.N. Modi &

Dr. S.M. Seth

HYDRAULICS AND FLUID

MECHANICS INCLUDING

HYDRAULIC MACHINES

STANDARD

BOOK HOUSE2005

5 PENTON / IPC FUNDAMENTAL HYDRAULICS PENTON / IPC 1971

Web site Reference

www.hydroline.com

www.fluidpowerjournal.com

www.hmti.com

www.rexroth.com

www.eaton.com

www.industrialcontrol.com

www.polyhydron.com

69

9. APPENDICES

9.1 HEAT EXCHANGER:

In a hydraulic system, part of the output is transformed into heat at various

points (valves/lines) i.e. the fluid gets heated up. If the heat radiated from the tank is too low, the

induced temperature lies above the desired operating temperature, due to the amount of heat

supplied and radiated. The fluid must be cooled. The cooler ensures that the fluid temperature

does not exceed a certain limit. There are two types of heat exchangers:

9.1.1 AIR COOLED HEAT EXCHANGERS:

These types of coolers use moving air to dissipate heat from the oil. The cooler has fins,

which expose more oil to the air. Fluid coming from the system flows back into the system

through a tube cooled by means of a fan wheel. 5

A basic advantage of the oil–air cooler is that the air is available practically everywhere. The

fan wheel must be driven in someway, and the cooler noise cannot always be reduced.

The oil-air cooler is designed to function simultaneously as a coupling protection. The

hub of the fan wheel is fixed to the motor shaft. Air flows from inside over the finned tube,

which is wound several times round the fan wheel. The fluid flows back to tank through this

ribbed tube and dissipates heat.

The leakage oil from the variable displacement vane pump is cooled before returning to tank by

this cooler designed as coupling protection.

Fig-9.1 AIR-COOLED TYPE

70

9.1.2 WATER COOLED HEAT EXCHANGERS:

These coolers feed either the water or the pressure fluid into cooling tubes, while the fluid or

water circulates the tubes. Oil-water coolers have a greater cooling power than oil-air coolers,

because the difference in temperature between the coolant and pressure fluid is generally greater.

Fig-9.2

9.2 SEALS:

One of the main disadvantages of any hydraulic system is that it uses fluid as its medium

of transmission. Due to its fluidity it needs protection against movement in directions it is not

supposed to go. Every hydraulic system has many joints. Both internal and external leakages

create the following problems:

Waste of fluid

Fire hazards

Decrease in efficiency and sometimes even failure of the system.

71

Fig – 9.3

9.3 FILTERS:

The most common device installed in the hydraulic systems to prevent foreign particles and

contamination from remaining in the system is referred to as filters. They may be located in the

reservoir, in the return line, in the pressure line, or in any location in the system where the

designer of the system decides its usage.

Fig –9.4 FILTERS

The reliability of the hydraulic system depends on the cleanliness of the system, i.e. on

filtration. The filter serves to reduce the level of dirt in a pressure medium to a reliable level, and

thus to protect the individual elements from too much wear.

72

FACTORS THAT PLAY A PART ARE:

Dirt particle size

Number of particles

Speed of flow of the fluid

Tolerances, constructional conditions.

The particles, tiny pieces of dirt are measured in microns, the millionth of a meter.

Filtration is also stated in microns.

Various types of system filters are available, which differ from one another as

follows, depending on their arrangement in a hydraulic circuit:

9.3.1 SUCTION FILTERS:

The suction filter is located upstream from the inlet port of the pump. It protects the

pump from fluid contamination. Some suction filters may be simple inlet strainers submerged in

the fluid and others may be externally mounted. The disadvantage is that it is not easily

accessible and maintenance is therefore difficult.

9.3.2 PRESSURE FILTERS:

The pressure filter is located downstream from the system pump. They are designed to

handle the systems operating pressure and sized for specific flow rate in the pressure line where

they are installed. Pressure filters are especially suited for protecting sensitive components

directly downstream from the filter. Because of their location, pressure filters also help protect

the entire system from pump generated contamination.

9.3.3 RETURN LINE FILTERS:

The return line filter is the most used filter. It is located in the return line. It is the last

component through which the fluid passes before entering the reservoir. It may be the best choice

when the pump is the most contamination-sensitive component in the system. It captures wear

debris from the system components as well as particles entering through worn cylinder rod seals.

73

Because the return line filters are located immediately upstream from the reservoir, their pressure

rating and cost can be relatively low. Both pressure and return line filters are often available in a

duplex configuration that can provide continuous filtration.

9.3.4 OFF LINE FILTRATION:

This type of filtration system is also called as re-circulating/kidney loop/auxiliary

filtration. This is dependant on a machine’s hydraulic system. It consists of a pump, electric

motor, pressure filter and appropriate hardware connections. These components are installed as a

sub-system separate from the working hydraulic system. The pump moves the fluid continuously

from the reservoir, through the filter and back to the reservoir. This continuous recycling helps

maintain a constant cleanliness level of the fluid.

9.3.5 BREATHER FILTERS:

Breather filters are must for hydraulic systems ensuring clean air passing into the

reservoir, thus prolonging the life of system components. It serves two purposes as follows:

i. AS A FILLING FILTER:

When the tank is being filled with the fluid, the filter prevents large particles of dirt

entering the tank and the system filling up should therefore be carried out basically using a filler

filter.

ii. BAS A BLEED FILTER:

Where the fluid level varies, for example due to differential users the amount of air must

change. The air flowing into the tank is filtered.

9.4 PRESSURE GAUGES:

For safe and efficient operation, fluid power systems are designed to operate at a specific

pressure or temperature range. Most fluid power systems are provided with pressure gauges and

thermometers for measuring and indicating the pressure and the temperature in the system.

74

Fig –9.5 PRESSURE GAUGES

Pressure gauges are usually of two types:

1. Bellows or diaphragm type

2. Bourdon tube type

BOURDON TUBE GAUGES:

The bourdon tube is a device that senses pressure and converts the pressure to

displacement. Since the Bourdon-tube displacement is a function of the pressure applied, it may

be mechanically amplified and indicated by a pointer. Thus the pointer position indirectly

indicates pressure.

Fig-9.6 BOURDON GAUGES

The bourdon tube most commonly used is the C-shaped metal tube that is sealed at one

end and open at the other.