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“COVER PAGE”
PROJECT TITLE
A PROJECT REPORT
Submitted to
SUNRISE UNIVERSITY
in partial fulfilment for the award of the diploma of
POLYTECHNIC
In
MECHANICAL ENGINEERING
DEPARTMENT OF MECHANICAL ENGINEERING
SUNRISE UNIVERSITYALWAR
RAJASTHAN, INDIA
MAY 2014
“Annexure1”PROJECT TITLE
<Font Size 16><1.5 line spacing>
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A PROJECT REPORT<Font Size 14><Italic>
Submitted toSUNRISE UNIVERSITY
<Font Size 14><Bold
in partial fulfilment for the award of the diploma of<Font Size 14><1.5 line spacing><Italic>
POLYTECHNIC<Font Size 16><Bold
IN MECHANICAL ENGINEERING
<Font Size 14><Bold
DEPARTMENT OF MECHANICAL ENGINEERING<Font Size 12><Bold
SUNRISE UNIVERSITY<Font Size 16><Bold
ALWAR RAJASTHAN, INDIA
<Font Size 12><BoldMAY 2014
<Font S ize 14><Bold
2
CERTIFICATE
This is to certify that the project report entitled “ TITLE OF PROJECT WORK ”
submitted by NAME OF GROUP to the SunRise University Alwar,Rajasthan in partial
fulfilment for the award of Diploma of Polytechnic in Mechanical Engineering is a confide
record of the project work carried out by him under my supervision during the year 2015-
2016.
Submitted to: Submitted by:
Name of incharge Name of student(Roll)
Designation
Name (Project Guide) Designation
SUNRISE UNIVERSITYBagad Rajput, ALWAR-301030(Raj.)
INDIA
3
ACKNOWLEDGEMENT
I take this opportunity to express my profound gratitude and deep to my mentor Mr.
Vinayak Hemadri for his exemplary guidance, monitoring and constant encouragement
throughout the course of this thesis. The blessing, help and guidance given by him time to
time shall carry me a long way on the journey of life in which I am about to embark. I also
take this opportunity to express a deep sense of gratitude to the mentor for his cordial
support, valuable information and guidance, which helped me in completing this task through
various stages.
Lastly, I thank almighty, my parents, and friends for their constant encouragement
without which this assignment would not be completed.
4
ABSTRACT
The U shaped hydraulic pipe bending machine is designed to bend the pipe in u shape to
required dimensions. This pipe bending machine can also perform bend the pipe in various
shaped such as V shaped, Z shaped etc whereas the tool for bending is important. In this
project we use manual handle, hydraulic cylinder, bending tool, hydraulic cylinder with
pressurised cylinder and die with its holder and a ram. This project is cost efficient and
economical for the bending function. This type of arrangements is very easy in operation and
may be used highly in small scale industries in order to bend the pipe in hand. So this project
can also be done in large scale with various ram tool shapes.
5
TABLE OF CONTENTS
CHAPTER NO TITLE PAGE NO
ABSTRACT 5
LIST OF FIGURES 6
LIST OF TABLES 8
1. INTRODUCTION
1.1 PRINCIPLES OF HYDRAULIC JACK 09
1.2 PASCAL’S LAW 09
1.3 ADVANTAGES 09
1.4 DISADVANTAGES 09
1.5 PARTS OF A HYDRAULIC CYLINDER 13
1.6 CYLINDER BARREL 13
1.7 CYLINDER BASE OR CAP 14
1.8 CYLINDER HEAD 14
1.9 PISTON 14
1.10 PISTON ROD 14
1.11 SEAL GLAND 14
1.12 SEALS 15
CHAPTER 2
2.1 BLOCK DIAGRAM 13
2.2 OTHER INFORMATION
2.3 SALIENT FEATURES OF HYDRAULIC OPERATED MACHINES 16
6
2.4 DESIGN CONSIDERATIONS 17
2.5 EFFICIENCY OF OPERATION 17
2.6 USES OF HYDRAULIC BENDING MACHINE 18
2.7 PRINCIPLES OF HYDRAULIC DRIVE 19
2.8 STRUCTURE AND CHARACTERISTICS
OF THE HYDRAULIC BENDING MACHINE 21
2.9 LIFTING AND INSTALLATION OF
HYDRAULIC BENDING MACHINE 22
CHAPTER 3
3.1 HYDRAULIC UNIT FUNCTION 24
3.1.1 GEAR PUMP 24
3.1.2 VANE PUMP 24
3.1.3 AXIAL PISTON PUMP 24
3.1.4 RADIAL PISTON PUMP 24
3.1.5 CONTROL VALVES 25
3.1.6 PRESSURE RELIEF VALVES 26
3.2 COMPONENTS OF HYDRAULIC UNIT 27
3.2.1ACTUATORS 27
3.2.2 RESERVOIR 27
3.2.3 ACCUMULATORS 28
7
3.2.4 HYDRAULIC FLUID 28
3.2.5 FILTERS 28
3.2.6 TUBES, PIPES AND HOSES 29
3.2.7 SEALS, FITTINGS AND CONNECTIONS 30
3.3 EQUIPMENT DESCRIPTION 31
3.3.1 COMPRESSOR 31
3.3.2 CENTRIFUGAL COMPRESSORS 31
3.3.3 AXIAL-FLOW COMPRESSORS 32
3.3.4 RECIPROCATING COMPRESSORS 32
3.4 CONTROL UNIT 33
3.5 TYPES 34
3.6 COMMON USES 34
3.7 PNEUMATIC CYLINDER 35
3.8 TYPES OF PNEUMATIC CYLINDERS 35
3.9 GAUGE PRESSURE 37
3.10 ATMOSPHERIC PRESSURE 37
3.11 MECHANICAL MODEL 38
3.12 HYDRAULIC JACK 38
3.13 WORKING PROCESS OF HYDRAULIC MACHINE 39
3.14 BASIC IDEA BEHIND HYDRAULIC SYSTEM 40
3.15 HYDRAULIC MULTIPLICATION 41
3.15.1 SAMPLE INSTRUCTIONS
FOR HYDRAULIC BENDING MACHINE OPERATION 42
8
CHAPTER 4
4.1 APPLICATIONS AND ITS ADVANTAGES 43
4.1.1APPLICATION AREAS 43
4.2 ADVANTAGES 44
CHAPTER 5
CHAPTER 6
6.1 CONCLUSION 47
REFERENCES 48
9
LIST OF FIGURES
FIGURE.NO NAME PAGE.NO
1.1 Pascal’s Demonstration Setup 11
2.1.1 Hydraulic Pipe Bending Unit 18
2.6.1 Hydraulic Pipe Machine 22
3.1.5.1 Hydraulic Press 27
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CHAPTER 1
1.1 INTRODUCTION
There are mainly two types of fluid power systems:
Hydraulic Power System( employing liquids)
Pneumatic Power System(employing air)
1.2 Pascal’s law
Pascal’s law states that the pressure applied anywhere to a confined liquid is transmitted
equally to every portion of the surface of the containing vessel. When a force is applied to the
liquid by a piston, the liquid transmits this force equally to all surfaces of the container.
Fig 1.1: Pascal’s demonstration setup
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1.3 ADVANTAGES
The process uses low- cost energy source
Large machines frames are not required on the process
No extra skill is required for operating this system
Easier maintenance
Less loss in power transmission
1.4 DISADVANTAGES
Machining work is very complicated
Very sturdy base needed
Hydraulics components cost is high
These are just a few of the safety precautions that every forklift operator should take.
Thorough training and a complete understanding of forklift operation and safety, combined
with safety forklift attachments can and do save lives. Hydraulic jack works on the principle
of ―Pascal‘s law‖. When the handle is operated, the plunger reciprocates then the oil from
the reservoir is sucked into the plunger cylinder during upward stroke of the plunger through
the suction valve. The oil in the plunger cylinder is delivered into the ram cylinder during the
downward stroke of the plunger through the delivery valve. This pressurized oil lifts the load
up, which is placed on top plate of the ram. After the work is completed the pressure in the
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ram cylinder is released by unscrewing the lowering screw thus the pressure releases and the
ram is lowered, then the oil is rushed into the reservoir. It consists of plunger cylinder on one
side and ram cylinder on the other side. These two cylinders are mounted on base which is
made of mild steel. Plunger cylinder consists of plunger which is used to build up the
pressure by operating the handle. Plunger cylinder consists of two non-return valves i.e. one
for suction and other for delivery.
Ram cylinder consists of ram which lifts the load. The ram cylinder connected to
delivery valve of plunger cylinder. It is also consists of lowering screw this is nothing but a
hand operated valve used for releasing the pressure in the ram cylinder for get down the load.
the fuel consumption reduction effect at in-house measurement courses. The fuel reduction
effect was obtained in any course. In particular, the effect of no less than 29% was obtained
at a high load course where there is a lot of switch back in a short distance assuming loading
work to a truck. shows the frequency distribution of engine speed and torque at the high load
course This shows that as a circle is larger, the frequency is higher. It can be seen that large
circles move to the small fuel consumption side as compared with those for the conventional
forklift. In particular, HST forklift used the range where there was little change in engine
speed during acceleration and fuel consumption was small for a long time. Therefore, the
result as intended was obtained.
In cooperation with Power Train Development Centre and Hydraulic Equipment Technical
Centre, we have realized commercialization of forklifts installed with electronically
controlled HST and CLSS hydraulic system for the first time as Komatsu. We will continue
to make efforts to expand the model line-up installed with HST and CLSS in the future and at
13
the same time to aim at further technological leaps to develop these models to be more
attractive to customers.
This project is to bend the rod at the specified dimensions which is used in the building
construction which called as Stirrups. Stirrup is an important reinforced element which acts
as a shear reinforcement. Presently, stirrups are made manually, which suffers from many
drawbacks like lack of accuracy, low productivity and resulting into severe fatigue in the
operator. In manual stirrup making process, operators not only subjecting their hands to hours
of repetitive motion, but in many occasions it results into several musculoskeletal disorders
(MSDs). The project is designed based on the principle of Hydraulic system. The hydraulic
load has more power compare to the other type of loads like pneumatic and electric. By using
heavy loads we can increase the productivity of the product. The manual stirrup making
process suffers from the many drawbacks. The construction worker not only subject their
hands to hours of repetitive motion but also sometimes suffers internal injury to his body
organ i.e. disorder carpal tunnel syndrome CTS, slipped disc problem etc. A Hydraulic
cylinder (also called a linear hydraulic motor) is a mechanical actuator that is used to give a
unidirectional force through a unidirectional stroke. It has many applications,
notably in engineering vehicles, industrial application, civil applications. Hydraulic cylinders
get their power from pressurized hydraulic fluid, which is typically oil, air. The hydraulic
cylinder consists of a cylinder barrel, in which a piston connected to a piston rod moves back
and forth. The barrel is closed on one end by the cylinder bottom (also called the cap) and the
other end by the cylinder head (also called the gland) where the piston rod comes out of the
cylinder. The piston has sliding rings and seals. The piston divides the inside of the cylinder
into two chambers, the bottom chamber (cap end) and the piston rod side chamber (rod end /
head end).
14
Flanges, trunnions, clevises, Lugs are common cylinder mounting options. The piston rod
also has mounting attachments to connect the cylinder to the object or machine component
that it is pushing / pulling. A hydraulic cylinder is the actuator or "motor" side of this system.
The "generator" side of the hydraulic system is the hydraulic pump which brings in a fixed or
regulated flow of oil to the hydraulic cylinder, to move the piston. The piston pushes the oil
in the other chamber back to the reservoir.
Hydraulic machines are machinery and tools that use liquid fluid power to do simple work.
Heavy equipment is a common example. In this type of machine, hydraulic fluid is
transmitted throughout the machine to various hydraulic motors and hydraulic cylinders and
which becomes pressurized according to the resistance present. The fluid is controlled
directly or automatically by control valves and distributed through hoses and tubes. The
popularity of hydraulic machinery is due to the very large amount of power that can be
transferred through small tubes and flexible hoses, and the high power density and wide array
of actuators that can make use of this power. Hydraulic machinery is operated by the use of
hydraulics, where a liquid is the powering medium.
1.5 Parts of a hydraulic cylinder
A hydraulic cylinder consists of the following parts:
1.6 Cylinder barrel
The main function of cylinder body is to hold cylinder pressure. The cylinder barrel is mostly
made from a seamless tube. The cylinder barrel is ground and/or honed internally with a
typical surface finish of 4 to 16 micro inch. Normally hoop stresses are calculated to optimize
the barrel size.
15
1.7 Cylinder base or cap
The main function of cap is to enclose the pressure chamber one end. The cap is connected to
the body by means of welding, threading, bolts, tie rod. Cap also perform as a cylinder
mounting components. Cap size determined based on the bending stress.
1.8 Cylinder head
The main function of head is to enclose the pressure chamber from other end. Head contains
an integrated rod sealing arrangement or option to accept a seal gland. The head is connected
to the body by means of threading, bolts, tie rod. A static seal / o-ring used in between head
and barrel.
1.9 Piston
The main function of piston is to separate pressure zone in side barrel. The piston is
machined with grooves to fit elastomeric or metal seals and bearing elements. These seals can
be single acting or double acting. This difference in pressure between the two sides of the
piston causes the cylinder to extend and retract. Piston is attached with the piston rod by
means of threads, bolts, nuts to transfer the linear motion.
1.10 Piston rod
The piston rod is typically a hard chrome-plated piece of cold-rolled steel which attaches to
the piston and extends from the cylinder through the rod-end head. In double rod-end
cylinders, the actuator has a rod extending from both sides of the piston and out both ends of
the barrel. The piston rod connects the hydraulic actuator to the machine component doing
the work. This connection can be in the form of a machine thread or a mounting attachment.
1.11 Seal gland
The cylinder head is fitted with seals to prevent the pressurized oil from leaking past the
interface between the rod and the head. This area is called the seal gland. The advantage of
seal gland is easy removal and seal replacement. The seal gland contains primary seal,
16
secondary seal / buffer seal, bearing elements, wiper / scraper and static seal. In some cases,
especially in small hydraulic cylinders, the rod gland and the bearing elements are made from
a single integral machined part.
1.12 Seals
The seals are considered / design as per the cylinder working pressure, cylinder speed,
operating temperature, working medium and application. Piston seals are dynamic seals, can
be single acting or double acting. Generally speaking, Elastomers seals made from nitrile
rubber, Polyurethane or other materials are best in lower temperature environments, while
seals made of Fluorocarbon Viton are better for higher temperatures. Metallic seals are also
available commonly used cast iron for seal material. Rod seal are dynamic seals and
generally single acting. The compounds of rod seals are nitrile rubber, Polyurethane,
Fluorocarbon Viton. Wiper / scraper are used to eliminates contaminants such as moisture,
dirt, and dust, which can cause extensive damage to cylinder walls, rods, seals and other
components. The common compound for wiper is polyurethane. Metallic scraper are used for
sub zero temperature application, application where foreign material can deposit on rod. The
bearing element / wear bands are use to eliminate metal to metal contact. The wear bands are
design as per the side load requirements. The primary compounds for wear bands are filled
PTFE, Woven fabric reinforced polyester resin, bronze.
17
CHAPTER 2
2.1 BLOCK DIAGRAM
Fig 2.1.1: Hydraulic Pipe Bending Unit
The Hydraulic oil employed in this process is initially stored in a tank of 40 litres
capacity. A filter air breather is mounted on the tank for filling the air passing into the
reservoir and straining the oil while filling the reservoir. In addition a suction strainer is used
to suck the oil into the system. An electrical motor of 2HP is coupled to vane pump to drive
the fluid. When the motor runs, coupling that connects motor and the pump causes the
rotation of the pump in turn. Depending upon the speed of the rotation of the pump, a vacuum
is created which make the oil to be sucked and raised into the system. The pressure of oil
depends upon the speed of the system. The pressurized oil passes through an inline check
valve that prevents the return flow of the oil into the pump. This is followed by a pressure
line filter to filter the oil from dust partials. A Pressure Relief Valves is connected parallel to
18
the output line of the filter This relief valve is used to prevent the system from the effect
caused by excess pressure this limit, the valve get activated and releases the excess pressure.
The flow from these valves is measured using a pressure gauge mounted on the pipe line and
it can be adjusted. The pressurised oil then enters the Directional Control Valve (P-40). The
DCV used here is a P-40 4/3 Joystick operated spring centred DCV. At other end of DCV is
connected to a Double acting cylinder. This cylinder is involved in the bending operation.
When the left spool is activated, the oil flows into the piston end the core of the cylinder
causing the extension of the cylinder. The extension force of the cylinder is used for bending
operation. Once the bending is completed, the right spool is activated. This causes the
retraction of the cylinder. This process is repeated for bending stirrups controlled manually.
2.2 Other information:
The NCX tube bending machines have a clamping die, pressure die, and mandrel and bend
head, which are all hydraulically operated. To enhance the usefulness of these NCX
machines, electro pneumatics has developed the NCXR Series. These tube bending machines
have a pre-settable linear and rotary indexing facility for multi-plane bends, in addition to the
clamp, pressure die, mandrel and bend arm. These hydraulic, semi-automatic machines can
handle tubes from 6 mm to 325 mm outside diameter, ft is possible to bend tubes of a variety
of materials with round, square or rectangular sections and different profiles, which laminates
the need for locating fixtures on the machine. A carriage with a manual/hydraulic chucking
arrangement that is capable of traversing the length of the machine is provided. Electro
pneumatics user-friendly programmable microprocessor based numerical 'Smart bend 4101
series controllers are specially designed for these machines. With these machines, all
operations of the bending process are done automatically, while rotation and linear
orientation of the component between two bends is done manually by the operator against
pre-settable stops.
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2.3 SALIENT FEATURES OF HYDRAULIC OPERATED MACHINES
All machines are made of high quality graded castings, which are properly aged and stress
relieved using vibratory stress relieving equipments, for taking care of any seasonal effects on
castings. Thus enhancing the life of machines.
All the machines are hand scrapped for long lasting precision and reliability. The
Hydraulic series machines are designed with the principles of column movement (Y axis).
This enhances the overall life of machine and provides high accuracy for jobs for many years.
The hydraulic pumps are designed especially for surface grinding machine in house. These
pumps provide smooth, vibration free movements for superior job finishes. The slides (X &
Y) are coated with turcite lining, a slide way material with special embedding properties, this
considerably reduces the friction between slides for very easy and smooth movement thereby
reducing wear & tear of machines to a large extent.
All the three axis as well as cross feed and vertical screws are continuously lubricated with
specially designed inbuilt lubricating system. This not only makes the machine very easy to
operate but also reduces wear and tear of all moving parts. All the machines come with
special spindles assembled with high quality low vibration motors, as well as fitted with very
high quality imported bearings which are greased packed for life, providing a very precise
grinding action for best surface finishes as well as best flatness for jobs.
All hydraulic machines come with specially designed moveable tower electrical panel.
These panels provide easy to use functions for operation of machines. Panels have been
provided with sufficient interlocks for accident free operations. All the electrical and other
bought out items are of high quality and from reputed brands. Care is taken that such items
are easily available in market for easy maintenance and replacements.
Our machines are backed with 1 year workmanship guarantee providing peace of minds
20
to customers.
2.4 Design Considerations
Pressure and Temperature ratings
Interlocks for sequential operations
Emergency shutdown features
Power failure locks
Operation speed
Environment conditions
2.5 Efficiency of Operation
Keep system Simple, Safe and Functional
Access to parts need repair or adjustment
Design to keep min operational cost
Design to prevent and remove contamination
Hydraulic bending machine, including brackets, table and clamping plate, the table placed in
the bracket, Workbench from the platen base and base connected by a hinge and the clamping
plate, the base of the seat shell, coil and cover, coil placed in the seat shell depression, the
depression at the top covered with a lid. used by the wire coil is energized, power on the
platen gravity, thereby clamping the sheet between the platen and the base due to the
electromagnetic force folder hold the plate can be made into a variety of work piece
Requirements, but also on the sidewall of the work piece to be processed.
2.6 USES OF HYDRAULIC BENDING MACHINE
Our range of Hydraulic Breading Machine is used for selectively dispensing flour breading or
free flowing breading onto a food product wherein the machine has a frame and conveyor
structure supported on the frame defining a conveyance path having a product inlet end and a
product outlet end. This machine also comes with a breading hopper attached to the frame
21
adjacent to the inlet end for applying a coating of breading to the food product and also a
breading pumping slot structure attached to the frame for providing breading to the input end
of the conveyor with a fluffier mechanism mounted on the pumping slot structure to break up
any caking or lumping of the breading on the conveyor prior to the point of introduction of
the food product to the conveyor.
Fig 2.6.1: Hydraulic Pipe Machine
The Mechanical Screw jacks have been replaced with hydraulically operated jacks. This
reduces requirement of man power upto 40% and the Roll bending cycle time is reduced by
40%. The Machine has a capacity to pre bend but with a flat edge of 40% of Top Roll Dia of
the machine. It is not out of place to highlight that the pre bend capacity of a given Plate
Bending machine is approximately 80% of its roll bending capacity, i.e, A plate bending
machine having a capacity of 16 mm thick is capable of Pre bending plates up to 12 mm
thickness when equipped with hydraulically operated jacks. Nevertheless the reduced man
power and production makes for the flat edge. The machine is priced almost less than half of
22
the machines doing the same job across the globe. The fact remains that not a single machine
is available which has zero flat edge. The minimum flat edge is generally 3 to 6 times the
thickness of the plate being bent. The Machines have longer functional life, consumes less
electricity and ensures optimum performance. In addition to these features, offered range is
best alternative to CNC bending machines, it has appreciating production capacity. The range
produces wrinkle free, smooth bends and it is also an interchangeable set of tooling for each
type of bend. Our range has aforementioned features as we use best quality raw material for
its manufacturing under the eye of professionals. A hydraulic drive system is a drive or
transmission system that uses pressurized hydraulic fluid to drive hydraulic machinery. The
term hydrostatic refers to the transfer of energy from flow and pressure, not from the kinetic
energy of the flow. A hydraulic drive system consists of three parts: The generator (e.g. a
hydraulic pump), driven by an electric motor, a combustion engine or a windmill; valves,
filters, piping etc. (to guide and control the system); the motor (e.g. a hydraulic motor or
hydraulic cylinder) to drive the machinery.
2.7 Principles of Hydraulic Drive
Pascal's law is the basis of hydraulic drive systems. As the pressure in the system is the same,
the force that the fluid gives to the surroundings is therefore equal to pressure × area. In such
a way, a small piston feels a small force and a large piston feels a large force. The same
principle applies for a hydraulic pump with a small swept volume that asks for a small torque,
combined with a hydraulic motor with a large swept volume that gives a large torque. In such
a way a transmission with a certain ratio can be built. Most hydraulic drive systems make use
of hydraulic cylinders. Here the same principle is used — a small torque can be transmitted in
to a large force. By throttling the fluid between the generator part and the motor part, or by
using hydraulic pumps and/or motors with adjustable swept volume, the ratio of the
transmission can be changed easily. In case throttling is used, the efficiency of the
23
transmission is limited. In case adjustable pumps and motors are used, the efficiency,
however, is very large. In fact, up to around 1980, a hydraulic drive system had hardly any
competition from other adjustable drive systems. Nowadays, electric drive systems using
electric servo-motors can be controlled in an excellent way and can easily compete with
rotating hydraulic drive systems. Hydraulic cylinders are, in fact, without competition for
linear forces. For these cylinders, hydraulic systems will remain of interest and if such a
system is available, it is easy and logical to use this system for the rotating drives of the
cooling systems, also. A hydraulic is a machine using a hydraulic cylinder to generate a
compressive force. It uses the hydraulic equivalent of a mechanical lever, and was also
known as a Brahma press after the inventor, Joseph Brahma, of England. He invented and
was issued a patent on this press in 1795. As Brahma (who is also known for his development
of the flush toilet) installed toilets, he studied the existing literature on the motion of fluids
and put this knowledge into the development of the press.
2.8 Structure and characteristics of the hydraulic bending machine:
1. All-steel welded construction of sufficient strength and rigidity.
2. Hydraulic drive, the machine at both ends of the fuel tank is placed in the slider on the
Direct drive slide work.
3. Slider synchronization mechanism with torsion bar forced synchronization.
4. Using the machinery of block structure, stable and reliable.
5. Slide stroke motor fast tune, manual fine tuning, counter display
5. The Wedge deflection compensation mechanism to ensure that the higher bending
accuracy.
24
2.9 Lifting and installation of hydraulic bending machine
Lifting and installation of hydraulic plate bending machine, hydraulic plate bending
machine and the whole centre of gravity higher, before re-light, so the process of lifting and
handling and installation should be noted that the centre of gravity, so as not to cause the
machine to turn over accident, lifting, lifting wire angle as small as possible, the same to
ensure that the machine precision. hydraulic plate bending machine left and right columns in
the work surface at the benchmark for measuring the level of vertical and horizontal direction
should be less than or equal to 1000: 0.2, according to the foundation plan in advance,
prepare the ground, the hydraulic plate bending machine is installed on the basis of, and
install anchor bolts, the final grouting be all solidified cement retaining screws, proof-reading
level.
25
CHAPTER 3
3.1 HYDRAULIC UNIT FUNCTION
Hydraulic pumps supply fluid to the components in the system. Pressure in the system
develops in reaction to the load. Hence, a pump rated for 5,000 psi is capable of maintaining
flow against a load of 5,000 psi. Pumps have a power density about ten times greater than an
electric motor (by volume). They are powered by an electric motor or an engine, connected
through gears, belts, or a flexible elastomeric coupling to reduce vibration.
Common types of hydraulic pumps to hydraulic machinery applications are;
3.1.1 Gear pump: cheap, durable (especially in g-rotor form)., simple. Less efficient,
because
they are constant (fixed) displacement, and mainly suitable for pressures below 20 MPa
(3000 psi).
3.1.2 Vane pump: cheap and simple, reliable. Good for higher-flow low-pressure output.
3.1.3 Axial piston pump: many designed with a variable displacement mechanism, to vary
output flow for automatic control of pressure. There are various axial piston pump designs,
including swash plate (sometimes referred to as a valve plate pump) and check ball
sometimes referred to as a wobble plate pump). The most common is the swash plate pump.
A variable-angle swash plate causes the pistons to reciprocate a greater or lesser distance per
rotation, allowing output flow rate and pressure to be varied (greater displacement angle
causes higher flow rate, lower pressure, and vice versa).
3.1.4 Radial piston pump: A pump that is normally used for very high pressure at small
flows. Piston pumps are more expensive than gear or vane pumps, but provide longer life
operating at higher pressure, with difficult fluids and longer continuous duty cycles. Piston
pumps make up one half of a hydrostatic transmission.
26
3.1.5 Control valves
Directional control valves route the fluid to the desired actuator. They usually consist of a
spool inside a cast iron or steel housing. The spool slides to different positions in the housing,
intersecting grooves and channels route the fluid based on the spool's position. The spool has
a central (neutral) position maintained with springs; in this position the supply fluid is
blocked, or returned to tank. Sliding the spool to one side routes the hydraulic fluid to an
actuator and provides a return path from the actuator to tank. When the spool is moved to the
opposite direction the supply and return paths are switched.
Fig 3.1.5.1: Hydraulic Press
When the spool is allowed to return to neutral (center) position the actuator fluid paths are
blocked, locking it in position. Directional control valves are usually designed to be
stackable, with one valve for each hydraulic cylinder, and one fluid input supplying all the
valves in the stack. Tolerances are very tight in order to handle the high pressure and avoid
leaking, spools typically have a clearance with the housing of less than a thousandth of an
inch (25 μm). The valve block will be mounted to the machine's frame with a three point
pattern to avoid distorting the valve block and jamming the valve's sensitive components. The
spool position may be actuated by mechanical levers, hydraulic pilot pressure, or solenoids
which push the spool left or right. A seal allows part of the spool to protrude outside the
housing, where it is accessible to the actuator.
27
The main valve block is usually a stack of off the shelf directional control valves chosen by
flow capacity and performance. Some valves are designed to be proportional (flow rate
proportional to valve position), while others may be simply on-off. The control valve is one
of the most expensive and sensitive parts of a hydraulic circuit.
3.1.6 Pressure relief valves are used in several places in hydraulic machinery; on the return
circuit to maintain a small amount of pressure for brakes, pilot lines, etc., On hydraulic
cylinders, to prevent overloading and hydraulic line/seal rupture. On the hydraulic reservoir,
to maintain a small positive pressure which excludes moisture and contamination
Pressure regulators reduce the supply pressure of hydraulic fluids as needed for various
circuits.
Sequence valves control the sequence of hydraulic circuits; to ensure that one hydraulic
cylinder is fully extended before another starts its stroke, for example.
Shuttle valves provide a logical or function.
Check valves are one-way valves, allowing an accumulator to charge and maintain its
pressure after the machine is turned off, for example.
Pilot controlled Check valves are one-way valve that can be opened (for both directions)
by a foreign pressure signal. For instance if the load should not be held by the check valve
anymore. Often the foreign pressure comes from the other pipe that is connected to the motor
or cylinder.
Counterbalance valves are in fact a special type of pilot controlled check valve. Whereas
the check valve is open or closed, the counterbalance valve acts a bit like a pilot controlled
flow control.
Cartridge valves are in fact the inner part of a check valve; they are off the shelf
components with a standardized envelope, making them easy to populate a proprietary valve
block. They are available in many configurations; on/off, proportional, pressure relief, etc.
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They generally screw into a valve block and are electrically controlled to provide logic and
automated functions.
Hydraulic fuses are in-line safety devices designed to automatically seal off a hydraulic
line if pressure becomes too low, or safely vent fluid if pressure becomes too high.
Auxiliary valves in complex hydraulic systems may have auxiliary valve blocks to handle
various duties unseen to the operator, such as accumulator charging, cooling fan operation,
air conditioning power, etc. They are usually custom valves designed for the particular
machine, and may consist of a metal block with ports and channels drilled. Cartridge valves
are threaded into the ports and may be electrically controlled by switches or a microprocessor
to route fluid power as needed.
3.2 Actuators
Hydraulic cylinder
Swash plates are used in 'hydraulic motors' requiring highly accurate control and also
in 'no stop' continuous (360°) precision positioning mechanisms. These are frequently
driven by several hydraulic pistons acting in sequence.
Hydraulic motor (a pump plumbed in reverse)
hydrostatic transmission
Brakes
3.3 Reservoir
The hydraulic fluid reservoir holds excess hydraulic fluid to accommodate volume
changes from: cylinder extension and contraction, temperature driven expansion and
contraction, and leaks. The reservoir is also designed to aid in separation of air from the fluid
and also work as a heat accumulator to cover losses in the system when peak power is used.
Design engineers are always pressured to reduce the size of hydraulic reservoirs, while
equipment operators always appreciate larger reservoirs. Reservoirs can also help separate
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dirt and other particulate from the oil, as the particulate will generally settle to the bottom of
the tank. Some designs include dynamic flow channels on the fluid's return path that allow
for a smaller reservoir.
3.4 Accumulators
Accumulators are a common part of hydraulic machinery. Their function is to store
energy by using pressurized gas. One type is a tube with a floating piston. On one side of the
piston is a charge of pressurized gas, and on the other side is the fluid. Bladders are used in
other designs. Reservoirs store a system's fluid. Examples of accumulator uses are backup
power for steering or brakes, or to act as a shock absorber for the hydraulic circuit.
3.5 Hydraulic fluid
Also known as tractor fluid, hydraulic fluid is the life of the hydraulic circuit. It is usually
petroleum oil with various additives. Some hydraulic machines require fire resistant fluids,
depending on their applications. In some factories where food is prepared, either an edible oil
or water is used as a working fluid for health and safety reasons. In addition to transferring
energy, hydraulic fluid needs to lubricate components, suspend contaminants and metal
filings for transport to the filter, and to function well to several hundred degrees Fahrenheit or
Celsius.
3.6 Filters
Filters are an important part of hydraulic systems. Metal particles are continually
produced by mechanical components and need to be removed along with other contaminants.
Filters may be positioned in many locations. The filter may be located between the reservoir
and the pump intake. Blockage of the filter will cause cavitations and possibly failure of the
pump. Sometimes the filter is located between the pump and the control valves. This
arrangement is more expensive, since the filter housing is pressurized, but eliminates
cavitations problems and protects the control valve from pump failures. The third common
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filter location is just before the return line enters the reservoir. This location is relatively
insensitive to blockage and does not require a pressurized housing, but contaminants that
enter the reservoir from external sources are not filtered until passing through the system at
least once.
3.7 Tubes, pipes and hoses
Hydraulic tubes are seamless steel precision pipes, specially manufactured for
hydraulics. The tubes have standard sizes for different pressure ranges, with standard
diameters up to 100 mm. The tubes are supplied by manufacturers in lengths of 6 m, cleaned,
oiled and plugged. The tubes are interconnected by different types of flanges (especially for
the larger sizes and pressures), welding cones/nipples (with o-ring seal), several types of flare
connection and by cutrings. In larger sizes, hydraulic pipes are used. Direct joining of tubes
by welding is not acceptable since the interior cannot be inspected.
Hydraulic pipe is used in case standard hydraulic tubes are not available. Generally
these are used for low pressure. They can be connected by threaded connections, but usually
by welds. Because of the larger diameters the pipe can usually be inspected internally after
welding. Black pipe is non-galvanized and suitable for welding.
Hydraulic hose is graded by pressure, temperature, and fluid compatibility. Hoses are
used when pipes or tubes cannot be used, usually to provide flexibility for machine operation
or Maintenance. The hose is built up with rubber and steel layers. A rubber interior is
surrounded by multiple layers of woven wire and rubber. The exterior is designed for
abrasion resistance. The bend radius of hydraulic hose is carefully designed into the machine,
since hose failures can be deadly, and violating the hose's minimum bend radius will cause
failure. Hydraulic hoses generally have steel fittings swaged on the ends. The weakest part of
the high pressure hose is the connection of the hose to the fitting. Another disadvantage of
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hoses is the shorter life of rubber which requires periodic replacement, usually at five to
seven year intervals. Tubes and pipes for hydraulic applications are internally oiled before the
system is commissioned. Usually steel piping is painted outside. Where flare and other
couplings are used, the paint is removed under the nut, and is a location where corrosion can
begin. For this reason, in marine applications most piping is stainless steel.
3.8 Seals, fittings and connections
In general, valves, cylinders and pumps have female threaded bosses for the fluid
connection, and hoses have female ends with captive nuts. A male-male fitting is chosen to
connect the two. Many standardized systems are in use. Fittings serve several purposes;
1. To bridge different standards; O-ring boss to JIC, or pipe threads to face seal, for
example.
2. To allow proper orientation of components, a 90°, 45°, straight, or swivel fitting is
chosen as needed. They are designed to be positioned in the correct orientation and
then tightened.
3. To incorporate bulkhead hardware.
4. A quick disconnect fitting may be added to a machine without modification of
hoses or valves
A typical piece of heavy equipment may have thousands of sealed connection points and
several different types:
Pipe fittings, the fitting is screwed in until tight, difficult to orient an angled fitting
Correctly without over or under tightening.
O-ring boss, the fitting is screwed into a boss and orientated as needed, an
additional nut tightens the fitting, washer and o-ring in place.
Flare fittings, are metal to metal compression seals deformed with a cone nut and
pressed into a flare mating
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The working of the process is fully pneumatic and hydraulic operated where the air is
working medium. In this unit compressor is used to supply the compressed air at certain
pressure. This pressurized air is passed to the solenoid valve. The solenoid valve is controlled
by control unit. This solenoid valve is used to control the direction of flow of air to the
pneumatic cylinder. In this pneumatic cylinder the piston rod actuates due to the pressure. At
the end of piston rod bending tool is attached. So that tool bends the rod into required v
shape. Thus the work piece clamped on the frame is bending due to the reciprocating motion
of the bend.
3.3 EQUIPMENT DESCRIPTION
3.3.1 Compressor:
A gas compressor is a mechanical device that increases the pressure of a gas by reducing its
volume. Compressors are similar to pump: both increase the pressure on a fluid and both can
transport the fluid through a pipe. As gases are compressible, the compressor also reduces the
volume of a gas. Liquids are relatively incompressible; while some can be compressed, the
main action of a pump is to pressurize and transport liquids.
3.3.2 Centrifugal compressors use a rotating disk or impeller in a shaped housing to force
the gas to the rim of the impeller, increasing the velocity of the gas. A diffuser (divergent
duct) section converts the velocity energy to pressure energy. They are primarily used for
continuous, stationary service in industries such as oil refineries, chemical and petrochemical
plants and natural gas processing plants. Their application can be from 100 horsepower (75
kW) to thousands of horsepower. With multiple staging, they can achieve extremely high
output pressures greater than 10,000 psi (69 MPa).
Many large snowmaking operations (like ski resorts) use this type of compressor.
They are also used in internal combustion engines as superchargers and turbochargers.
Centrifugal compressors are used in small gas turbine engines or as the final compression
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stage of medium sized gas turbines. Sometimes the capacity of the compressors is written in
NM3/hr. Here 'N' stands for normal temperature pressure (20°C and 1 atm) for example 5500
NM3/hr.
3.3.3 Axial-flow compressors are dynamic rotating compressors that use arrays of fan-like
airfoils to progressively compress the working fluid. They are used where there is a
requirement for a high flow rate or a compact design. The arrays of airfoils are set in rows,
usually as pairs: one rotating and one stationary. The rotating airfoils, also known as blades
or rotors, accelerate the fluid. The stationary airfoils,
also known as stators or vanes, decelerate and redirect the flow direction of the fluid,
preparing it for the rotor blades of the next stage. Axial compressors are almost always multi-
staged, with the cross-sectional area of the gas passage diminishing along the compressor to
maintain an optimum axial Mach number. Beyond about 5 stages or a 4:1 design pressure
ratio, variable geometry is normally used to improve operation. Axial compressors can have
high efficiencies; around 90% polytropic at their design conditions. However, they are
relatively expensive, requiring a large number of components, tight tolerances and high
quality materials. Axial-flow compressors can be found in medium to large gas turbine
engines, in natural gas pumping stations, and within certain chemical plants.
3.3.4 Reciprocating compressors use pistons driven by a crankshaft. They can be either
stationary or portable, can be single or multi-staged, and can be driven by electric motors or
internal combustion engines. Small reciprocating compressors from 5 to 30 horsepower (hp)
are commonly seen in automotive applications and are typically for intermittent duty. Larger
reciprocating compressors well over 1,000 hp (750 kW) are commonly found in large
industrial and petroleum applications. Discharge pressures can range from low pressure to
very high pressure (>18000 psi or 180 MPa). In certain applications, such as air compression,
multi-stage double-acting compressors are said to be the most efficient compressors
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available, and are typically larger, and more costly than comparable rotary units.[6] Another
type of reciprocating compressor is the swash plate compressor, which uses pistons moved by
a swash plate mounted on a shaft .Household, home workshop, and smaller job site
compressors are typically reciprocating compressors 1½ hp or less with an attached receiver
tank.
3.5 Control Unit:
The control unit coordinates the components of a computer system. It fetches the
code of all of the instructions in the program. It directs the operation of the other units by
providing timing and control signals. All computer resources are managed by the CU. It
directs the flow of data between the Central Processing Unit (CPU) and the other devices.
The control unit was historically defined as one distinct part of the 1946 reference model of
Von Neumann architecture. In modern computer designs, the control unit is typically an
internal part of the CPU with its overall role and operation unchanged. The control unit is the
circuitry that controls the flow of data through the processor, and coordinates the activities of
the other units within it. In a way, it is the "brain within the brain", as it controls what
happens inside the processor, which in turn controls the rest of the computer. The examples
of devices that require a control unit are CPUs and graphics processing units (GPUs). The
modern information age would not be possible without complex control unit designs. The
control unit receives external instructions or commands which it converts into a sequence of
control signals that the control unit applies to the data path to implement a sequence of
register transfer level operations.
Hardwired control units are implemented through use of sequential logic units,
featuring a finite number of gates that can generate specific results based on the instructions
that were used to invoke those responses. Hardwired control units are generally faster than
micro programmed designs.
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Their design uses a fixed architecture — it requires changes in the wiring if the
instruction set is modified or changed. This architecture is preferred in reduced instruction set
computers (RISC) as they use a simpler instruction set. The hardwired approach has become
less popular as computers have evolved as at one time, control units for CPUs were ad-hoc
logic, and they were difficult to design. The idea of microprogramming was introduced by
Maurice Wilkes in 1951 as an intermediate level to execute computer program instructions.
Micro programs were organized as a sequence of microinstructions and stored in special
control memory. The algorithm for the micro program control unit is usually specified by
flowchart description. The main advantage of the micro program control unit is the simplicity
of its structure. Outputs of the controller are organized in microinstructions and they can be
easily replaced. The control unit implements the instruction set of the CPU. It performs the
tasks of fetching, decoding, managing execution and then storing results. It may manage the
translation of instructions (not data) to micro-instructions and manage scheduling the micro-
instructions between the various execution units. On some processors the control unit may be
further broken down into other units, such as a scheduling unit to handle scheduling and a
retirement unit to deal with results coming from the pipeline; It is the main function of CPU.
3.6 Types
Many variations are possible on the basic, one way, one solenoid valve described above:
one or two solenoid valves;
direct current or alternating current powered;
different number of ways and positions;
3.7 Common uses
Solenoid valves are used in fluid power pneumatic and hydraulic systems, to control
cylinders, fluid power motors or larger industrial valves. Automatic irrigation sprinkler
systems also use solenoid valves with an automatic controller. Domestic washing machines
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and dish washers use solenoid valves to control water entry into the machine. Solenoid valves
are used in dentist chairs to control air and water flow. In the paintball industry, solenoid
valves are usually referred to simply as "solenoids”. They are commonly used to control a
larger valve used to control the propellant (usually compressed air or CO2).Besides
controlling the flow of air and fluids, solenoids are used in pharmacology experiments,
especially for patch-clamp, which can control the application of against or antagonist.
3.8 Pneumatic cylinder:
Pneumatic cylinders (sometimes known as air cylinders) are mechanical devices which use
the power of compressed gas to produce a force in a reciprocating linear motion. Like
hydraulic cylinders, pneumatic cylinders use the stored potential energy of a fluid, in this case
compressed air, and convert it into kinetic energy as the air expands in an attempt to reach
atmospheric pressure. This air expansion forces a piston to move in the desired direction. The
piston is a disc or cylinder, and the piston rod transfers the force it develops to the object to
be moved. Engineers prefer to use pneumatics sometime because they are quieter, cleaner,
and do not require large amounts of space for fluid storage.
Because the operating fluid is a gas, leakage from a pneumatic cylinder will not drip out and
contaminate the surroundings, making pneumatics more desirable where cleanliness is a
requirement. For example, in the mechanical puppets of the Disney Tiki Room, pneumatics
are used to prevent fluid from dripping onto people below the puppets. Although pneumatic
cylinders will vary in appearance, size and function, they generally fall into one of the
specific categories shown below. However there are also numerous other types of pneumatic
cylinder available, many of which are designed to fulfill specific and specialized functions.
3.9 Types of Pneumatic Cylinders:
i) Single-acting cylinder
Single-acting cylinders (SAC) use the pressure imparted by compressed air to create a
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driving force in one direction (usually out), and a spring to return to the "home" position.
More often than not, this type of cylinder has limited extension due to the space the
compressed spring takes up. Another downside to SACs is that part of the force produced by
the cylinder is lost as it tries to push against the spring. Because of those factors, single acting
cylinders are recommended for applications that require no more than 100mm of stroke
length.
ii) Double-acting cylinders
Double-acting cylinders use the force of air to move in both extends and retract
strokes. They have two ports to allow air in, one for outstroke and one for in stroke. Stroke
length for this design is not limited; however, the piston rod is more vulnerable to buckling
and bending. Addition calculations should be performed as well.
iii) Multi-stage, telescoping cylinders
Telescoping cylinders, also known as telescopic cylinders can be either single or
double acting. The telescoping cylinder incorporates a piston rod nested within a series of
hollow stages of increasing diameter. Upon actuation, the piston rod and each succeeding
stage "telescopes" out as a segmented piston. The main benefit of this design is the allowance
for a notably longer stroke than would be achieved with a single-stage cylinder of the same
collapsed (retracted) length. One cited drawback to telescoping cylinders is the increased
potential for piston flexion due to the segmented piston design. Consequently, telescoping
cylinders are primarily utilized in applications where the piston bears minimal side loading.
iv) Rod less cylinders
Some rod less types have a slot in the wall of the cylinder that is closed off for much
of its length by two flexible metal sealing bands. The inner one prevents air from escaping,
while the outer one protects the slot and inner band. The piston is actually a pair of them, part
of a comparatively long assembly. They seal to the bore and inner band at both ends of the
38
assembly. Between the individual pistons, however, are camming surfaces that "peel off" the
bands as the whole sliding assembly moves toward the sealed volume, and "replace" them as
the assembly moves away from the other end. Between the camming surfaces is part of the
moving assembly that protrudes through the slot to move the load. Of course, this means that
the region where the sealing bands are not in contact is at atmospheric pressure.
Depending on the job specification, there are multiple forms of body constructions
available:
Tie rod cylinders: The most common cylinder constructions that can be used in many
types of loads. Has been proven to be the safest form.
Flanged-type cylinders: Fixed flanges are added to the ends of cylinder, however, this
form of construction is more common in hydraulic cylinder construction.
One-piece welded cylinders: Ends are welded or crimped to the tube, this form is
inexpensive but makes the cylinder non-serviceable.
Threaded end cylinders: Ends are screwed onto the tube body. The reduction of material
can weaken the tube and may introduce thread concentricity problems to the system. Upon
job specification, the material may be chosen. Material range from nickel-plated brass to
aluminum, and even steel and stainless steel. Depending on the level of loads, humidity,
temperature, and stroke lengths specified, the appropriate material may be selected.
3.10 Gauge Pressure
Gauge pressure is zero-referenced against ambient air pressure, so it is equal to
absolute pressure minus atmospheric pressure. Negative signs are usually omitted.
3.10.1Atmospheric Pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of
air above that surface in the atmosphere of Earth (or that of another planet). In most
circumstances atmospheric pressure is closely approximated by the hydrostatic pressure
39
caused by the mass of air above the measurement point. Low-pressure areas have less
atmospheric mass above their location, whereas high-pressure areas have more atmospheric
mass above their location.
3.11 Mechanical model:
Mechanical Models offers a line of kits that provide everything you need to build an
attractive model using your mini lathe or mini mill. Our products include two cannons and
four Stirling cycle heat engines. The model engines are fully functional. Our kits are available
in three forms: material kits (material and drawings), assembly kits (fully machined parts
ready for assembly), and fully assembled models.
3.12 Hydraulic jack:
Hydraulic jacks are typically used for shop work, rather than as an emergency jack to
be carried with the vehicle. Use of jacks not designed for a specific vehicle requires more
than the usual care in selecting ground conditions, the jacking point on the vehicle, and to
ensure stability when the jack is extended. Hydraulic jacks are often used to lift elevators in
low and medium rise buildings. A hydraulic jack uses a fluid, which is incompressible, that is
forced into a cylinder by a pump plunger. Oil is used since it is self lubricating and stable.
When the plunger pulls back, it draws oil out of the reservoir through a suction check valve
into the pump chamber. When the plunger moves forward, it pushes the oil through a
discharge check valve into the cylinder. The suction valve ball is within the chamber and
opens with each draw of the plunger. The discharge valve ball is outside the chamber and
opens when the oil is pushed into the cylinder. At this point the suction ball within the
chamber is forced shut and oil pressure builds in the cylinder. In a bottle jack the piston is
vertical and directly supports a bearing pad that contacts the object being lifted. With a single
action piston the lift is somewhat less than twice the collapsed height of the jack, making it
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suitable only for vehicles with a relatively high clearance. For lifting structures such as
houses the hydraulic interconnection of multiple vertical jacks through valves enables the
even distribution of forces while enabling close control of the lift.
In a floor jack (aka 'trolley jack') a horizontal piston pushes on the short end of a Bell
crank, with the long arm providing the vertical motion to a lifting pad, kept horizontal with a
horizontal linkage. Floor jacks usually include castors and wheels, allowing compensation for
the arc taken by the lifting pad. This mechanism provides a low profile when collapsed, for
easy manoeuvring underneath the vehicle, while allowing considerable extension.
3.13 WORKING PROCESS OF HYDRAULIC MACHINE
A piece of hydraulic machinery uses a liquid (usually an oil) under pressure to
transmit energy. Let’s consider a simple system such as the one that operates the clutch on
my car. There are two cylinders with a piston in each and a small tube running between them.
When stepping on the clutch pedal, force the piston on one of the cylinders (known as the
master cylinder) deeper into the cylinder pushing fluid under pressure into the other cylinder.
The fluid exerts pressure on the other cylinder (the slave cylinder) and develops a force
which pushes on the clutch.
The relationship between force and pressure is:
Force = Area x Pressure
Which can be rearranged with algebra to
Pressure = Force / Area
This, by this is way, is why we measure pressure as in units such as pounds (force) per
square inch (area). If we make the master cylinder smaller than the slave cylinder, say 1
square inch and 2 square inches respectively, and assume that the pressures are equal, we find
that
Master cylinder force = 1/2 Slave cylinder force
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So we have to apply half as much force to the master cylinder (at the pedal) as we
want from the slave cylinder (the clutch) and I don't have to put as much force on the pedal to
operate the clutch. The force amplification is very similar to a lever (such as a pair of plyers)
but has the added benefit that the master and slave cylinders can be located anywhere. The
tube has many twists and turns, each one of which would require joints if a mechanical
system were used. Like a lever, and I must move the master cylinder twice as far at the slave
cylinder travels. Brakes in the car operate similarly, but the tube coming from the master
cylinder(s) are branched into several pistons at the wheels. Flexible tubing is used so that the
wheels can move freely when the car goes over bumps. Machines such as backhoes and
bulldozers use similar principles. However, in this case, the fluid is kept at constant pressure
continually by a pump connected to the engine and sent to the slave cylinders when the
operator opens a valve. This allows very large forces to be developed at the slave cylinder.
Pneumatic systems are similar to hydraulics, by use gases (typically air) rather than
liquid. Since gas can be compressed considerable, a lot of air can be forced into a tank and
the energy used later. This make pneumatics suitable for systems where large forces and
speed are required at the same type such as jackhammers, nail guns, or paintball guns.
3.14 BASIC IDEA BEHIND HYDRAULIC SYSTEM
The basic idea behind any hydraulic system is very simple: Force that is applied at
on point is transmitted to another point using an incompressible fluid. The fluid is almost
always an oil of some sort. The force is almost always multiplied in the process. The picture
below shows the simplest possible hydraulic system:
A Simple hydraulic system consisting of two pistons and an oil-filled pipe connecting
them. Click on the red arrow to see the animation. In this drawing, two pistons (red) fit into
two glass cylinders filled with oil (light blue) and connected to one another with an oil-filled
pipe. If you apply a downward force to one piston (the left one in this drawing), then the
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force is transmitted to the second piston through the oil in the pipe. Since oil is
incompressible, the efficiency is very good -- almost all of the applied force appears at the
second piston. The great thing about hydraulic systems is that the pipe connecting the two
cylinders can be any length and shape, allowing it to snake through all sorts of things
separating the two pistons. The pipe can also fork, so that one master cylinder can drive
more than one slave cylinder if desired. The neat thing about hydraulic systems is that it is
very easy to add force multiplication (or division) to the system.
3.15 Hydraulic multiplication:
The piston on the right has a surface area nine times greater than the piston on the left.
When force is applied to the left piston, it will move nine units for every one unit that the
right piston moves, and the force is multiplied by nine on the right-hand piston. Click the red
arrow to see the animation.
To determine the multiplication factor, start by looking at the size of the pistons.
Assume that the piston on the left is 2 inches in diameter (1-inch radius), while the piston on
the right is 6 inches in diameter (3-inch radius). The area of the two pistons is Pi * r2. The
area of the left piston is therefore 3.14, while the area of the piston on the right is 28.26. The
piston on the right is 9 times larger than the piston on the left.
Any force applied to the left-hand piston will appear 9 times greater on the right-hand
piston. So if you apply a 100-pound downward force to the left piston, a 900-pound upward
force will appear on the right. The only catch is that you will have to depress the left piston 9
inches to raise the right piston 1 inch. The brakes in your car are a good example of a basic
piston-driven hydraulic system. When you depress the brake pedal in your car, it is pushing
on the piston in the brake's master cylinder. Four slave pistons, one at each wheel, actuate to
press the brake pads against the brake rotor to stop the car.
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3.15.1 Sample instructions for hydraulic bending machine operation:
1. Clamp the bending machine to a flat work surface so that it is upright and secure.
2. Rotate the upper, short handle to a position above the bender.
3. Open the latch to make way for insertion of the tube. Insert the tube into the tube groove.
4. Close the latch around the tube to hold it in place. Lower the upper, short handle until the
roll dies rest against the tube and the angle-measure is aligned at zero degrees. Close the latch
firmly to clamp down tightly on the tube.
5. Press the upper, short handle down until the zero on the roll-support aligns with the desired
bend degree on the angle-measure.
6. Rotate the upper, short handle upward to release the newly bent tube.
7. Connect the hydraulic bending machine to an air compressor or hydraulic pump. Pull back
the brass coupling ring on the compressor or pump's hose and slide it onto the machine's
connector. Release the ring to secure the connection.
8. Set the machine's groove to receive the diameter of pipe for bending. Do this by moving
the machine's pin to the appropriate setting.
9. Slide the pipe into the machine's groove so that the point of the intended bends rests a top
the zero point of the angle-measure.
10. Turn on the compressor or pump.
11. Unlock the machine's safety lock and allow the machine to move and bend the pipe until
the indicator on the angle-measure reaches the desired degree of bend.
12. Close the safety lock on the bender to stop the bending process. Turn off the compressor
or pump.
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CHAPTER 4
4.1 APPLICATIONS AND ITS ADVANTAGES
4.1.1APPLICATION AREAS
Furniture industry
Chemical and boiler plants
Automobile and automotive component supplier industries
Agriculture
Moulded luggage manufacturers
Machines are well-known in the market due to their dimensional accuracy, high tensile
strength, corrosion resistance, compact design, simple operations and high reliability.
Applicable for bending pipes and other material in different angels, these are available in
different finishes and specifications. Clients can avail these machines at industry leading
prices. Bending Machines are used to bend metal pipe and tubing. Different bending
machines exist to handle each of these two different types of metal conduit. Hand-held
machines clamp to a work surface for stability and bend thin metal tubing. Larger, heavyduty
hydraulic machines connect to air pumps to increase torque and bend thick metal pipe. Each
machine usually comes equipped with an angle-measure to ensure the proper degree of bend.
Identify whether tubing or pipe needs bending, and chose the appropriate bending machine
for the job.
4.2 ADVANTAGES
Machining time reduced
Quick response
Simple in construction easy to maintain and repair.
Cost of the unit is less when compared to other systems.
Comparatively the operation cost is less
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Continuous operation is possible without stopping.
5000 kg push force, makes possible bending of heavy sections possible
Ease of operation
Gradual application of force prevents the pipe damage.
Quick release of the ram using relief valve makes operation fast.
Ease of maintenance.
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CHAPTER 5
47
48
CHAPTER 6
6.1 CONCLUSION
Thus the unit compressor is used to supply the compressed air at certain pressure. This
Pressurized air is passed to the solenoid valve. The solenoid valve is controlled by control
unit. This solenoid valve is used to control the direction of flow of air to the pneumatic
cylinder. In this pneumatic cylinder the piston rod actuates due to the pressure. Hydraulic
Pumps are used in V-type Bending machine which has a power density about ten times
greater than an electric motor (by volume). They are powered by an electric motor or an
engine, connected through gears, belts, or a flexible elastomeric coupling to reduce vibration.
And then the popularity of hydraulic machinery is due to the very large amount of power that
can be transferred through small tubes and flexible hoses, and the high power density and
wide array of actuators that can make use of this power. Hydraulic machinery is operated by
the use of hydraulics, where a liquid is the powering medium.
Here we are fabricating the model for press operation and it’s known as hydraulic
press machine. Hydraulics is a topic in applied science and engineering dealing with the
mechanical properties of liquids. Fluid mechanics provides the theoretical foundation for
hydraulics, which focuses on the engineering uses of fluid properties. In fluid power,
hydraulics is used for the generation, control, and transmission of power by the use of
pressurized liquids, here our system to making of pressing operation. The hydraulic press
depends on Pascal's principle: the pressure throughout a closed system is constant. At one end
of the system is a piston with a small cross-sectional area driven by a lever to increase the
force. Small-diameter tubing leads to the other end of the system.
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REFERENCES
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