Water jet machine report mechanical report

1
A
SEMINAR REPORT
On
WATER JET MACHINE
Submitted
By
MD ASIF
Department of Mechanical Engineering
GLOBAL TECHNICAL CAMPUS
GLOBAL COLLEGE OF TECHNOLOGY
ITS-1, IT Park, EPIP SITAPURA JAIPUR
DEPARTMENT OF MECHANICAL ENGG
Global College of Technology,
Sitapura, Jaipur 302022
2013-17

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Global College of Technology
DEPARTMENT OF MECHANICAL ENGINEERING
JAIPUR (RAJASTHAN)-302022
CERTIFICATE
GLOBAL COLLEGE OF TECHNOLOGY
Department of Mechanical Engineering
This is to certify that this seminar report on “Waterjet machine” by MD ASIF
13EGCME724. To the department of Mechanicalengineering, GCT Jaipur, for
award of degree of Btech in Mechanical Engineering is bonafide record of work
done by him. The content of the seminar record has not been to any college or
university for the award of degree.
Mr. SUNIL KUMAR JATOLIYA
MAHESH KUMAR YADAV MD ASIF
CO-ORDINATOR Student
(Signature) (Signature)

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ACKNOWLEDGEMENT
I would like to thank Mr Sunil Kumar Jatoliya (Assistant professor) and Mahesh Kumar yadav
(Assistant professor) department of Mechanical engineering. It would’nt be possible complete
the work without his assistance and hardwork, I’m obliged to his great effort on presenting us
firmly in seminar.
I would like to thank Mrs Bhavna Mathur, HOD, department of mechanical engineering, she
has always created good environment to enhance confidence and boost the student to present
themselves. She is good support through every thick and thin.
I’m also thankful to the hardworking effort of Prof.Mrs Renu Joshi(Director) Git. She is the
back bone of our each and every move.
MD ASIF
(13EGCME724)
Mechanical Engineering

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PAGE INDEX
 Content PAGE
NO
Certificate (I)
Acknowledgement (II)
Content (III)
List of figure (IV)
CHAPTER 1
1: INTRODUCTION 1
CHAPTER 2
2.1 HISTORY 4
2.1.1 1800 5
2.1.2 1850 7
2.1.3 1935 9
2.1.4 1990 10
CHAPTER 3
3.1 WORKING 11
3.1.1 High pressure water jet cutting 12
3.2 Type of pump 12
3.2.1 Intensifier 12
3.2.2 Direct drive 14
3.3 Principle of water jet cutting 15
3.3.1 Water jet cutting with pure water 17
3.3.2 Water jet cutting with abrasive 18
3.3.3 Water jet cutting with suspension 19
3.4 Part of water jet cutter 20
3.4.1 Electric motor and hydraulic pump 20
3.4.2 Directional control valve 21
3.4.3 Intensifier 22
3.4.4 Hydraulic cylinder 22

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3.4.5 Piston 23
3.4.6 Plunger 24
3.4.7 High pressure cylinder 25
3.4.8 Check valve 25
3.4.9 End cap 26
3.4.10 High pressure tubing 28
3.4.11 High pressure attenuate 28
3.4.12 Inlet water 30
3.5 Control and PLC 31
3.5.1 On-off valve 32
3.6 Abrasive feeding system 33
3.6.1 Pressurized bulk hopper 33
3.6.2 Mini-hopper 33
Conclusions 35
References 36

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List of figure
1.1 water jet cutter 1
1.2 Nozzle 2
1.3 Water jet cutter operation 3
2.1 Old model of water jet system 5
3.1 Horizontal water jet cutter 11
3.2 Intensifier pump 13
3.3 Direct drive 14
3.4 mouth piece of jet 15
3.5 Vertical water jet 16
3.6 Half section view of water jet 17
3.7 Suspension jet 19
3.8 Intensifier pump cabinet 20
3.9 Directional control valve 22
3.10 Intensifier 23
3.11 Hydraulic cylinder 23
3.12 piston and plunder 24
3.13 Ceramic plunger 24
3.14 High pressure cylinder 25
3.15 View of upper portion of Intensifier cabinet 26
3.16 Check valve body cross section 26
3.17 Fillet cap 27
3.18 Pressure alienator 29
3.19 Pressure fluctuation prior to accumulator 29
3.20 Water inlet system 30
3.21 On-off valve 32
3.22 Back hopper 33
3.23 Abrasive material feeding 34

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Chapter 1
1.1Introduction:-
A water jet cutter, also known as a water jet or water jet, is an industrial tool capable of cutting
a wide variety of materials using a very high-pressure jet of water, or a mixture of water and
an abrasive substance. The term abrasive jet refers specifically to the use of a mixture of water
and abrasive to cut hard materials such as metal or granite, while the terms pure water
jet and water-only cutting refer to water jet cutting without the use of added abrasives, often
used for softer materials such as wood or rubber.
Water jet cutting is often used during fabrication of machine parts. It is the preferred method
when the materials being cut are sensitive to the high temperatures generated by other methods.
Water jet cutting is used in various industries, including mining and aerospace, for cutting,
shaping, and reaming.
Fig1.1:- Water jet cutter
Cutting steel, concrete, glass and marble with water - sounds a bit far-fetched doesn’t it? Way
back in the 1950s, a forestry engineer by the name of Norman Franz started fiddling around

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with a high-pressure water stream to cut lumber. His aim was to streamline the process and
reduce the strain on traditional cutting equipment such as saw blades, which easily became
blunt and needed replacing. From these humble beginnings an idea was born, and over the next
couple of decades, water cutting became an unparalleled method for cutting materials of all
types, shapes and sizes.
FIG1.2:- nozzle
The end product? A water jet cutter – a machine capable of slicing metal and other materials
such as granite and marble with unbelievable accuracy. It does this by using a jet of water at
high velocity and pressure, sometimes mixed with an abrasive substance, depending on the
material that is being cut. Water jet cutters are usually used to cut materials such as rubber,
foam, plastics, leather, composites, stone, tiles, metals, food and paper. However, they can’t
cut tempered glass, diamonds and certain ceramics

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Fig1.3:- water jet cutter operation.

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CHAPTER 2
2.1 HISTORY:-
While using high-pressure water for erosion dates back as far as the mid-1800s
with hydraulic mining, it was not until the 1930s that narrow jets of water started to appear as
an industrial cutting device. In 1933, the Paper Patents Company in Wisconsin developed a
paper metering, cutting, and reeling machine that used a diagonally moving water jet nozzle to
cut a horizontally moving sheet of continuous paper.[2] These early applications were at a low
pressure and restricted to soft materials like paper.
Water jet technology evolved in the post-war era as researchers around the world searched for
new methods of efficient cutting systems. In 1956, Carl Johnson of Durox International in
Luxembourg developed a method for cutting plastic shapes using a thin stream high-pressure
water jet, but those materials, like paper, were soft materials.[3] In 1958, Billie Schwacha of
North American Aviation developed a system using ultra-high-pressure liquid to cut hard
materials.[4] This system used a 100,000 psi (690 MPa) pump to deliver a hypersonic liquid jet
that could cut high strength alloys such as PH15-7-MO stainless steel. Used as a honeycomb
laminate on the Mach 3 North American XB-70 Valkyrie, this cutting method resulted in
delaminating at high speed, requiring changes to the manufacturing process.[5]
While not effective for the XB-70 project, the concept was valid and further research continued
to evolve water jet cutting. In 1962, Philip Rice of Union Carbide explored using a pulsing
water jet at up to 50,000 psi (345 MPa) to cut metals, stone, and other materials.[6] Research by
S.J. Leach and G.L. Walker in the mid-1960s expanded on traditional coal water jet cutting to
determine ideal nozzle shape for high-pressure water jet cutting of stone,[7] and Norman Franz
in the late 1960s focused on water jet cutting of soft materials by dissolving long chain
polymers in the water to improve the cohesiveness of the jet stream.[8]
In the early 1970s, the desire to improve the durability of the water jet nozzle led Ray
Chadwick, Michael Kurko, and Joseph Corriveau of the Bendix Corporation to come up with
the idea of using corundum crystal to form a water jet orifice,[9] while Norman Franz expanded
on this and created a water jet nozzle with an orifice as small as 0.002 inches (0.05 mm) that
operated at pressures up to 70,000 psi (483 MPa).[10] John Olsen, along with George Hurlburt

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and Louis Kapcsandy at Flow Research (later Flow Industries), further improved the
commercial potential of the water jet by showing that treating the water beforehand could
increase the operational life of the nozzle.[11]
Fig 2.1 old model of water jet system
2.2.1 1800:-
Hydraulic mining had its precursor in the practice of ground sluicing, a development of
which is also known as "hushing", in which surface streams of water were diverted so as to
erode gold-bearing gravels. This was originally used in the Roman empire in the first centuries
AD and BC, and expanded throughout the empire wherever alluvial deposits occurred[2] The
Romans used ground sluicing to remove overburden and the gold-bearing debris in Las
Medullas of Spain, and Dolaucothi in Britain. The method was also used in Elizabethan
England & Wales (or rarel for developing lead, tin and copper mines.1
Water was used on a large scale by Roman engineers in the first centuries BC and AD when
the Roman empire was expanding rapidly in Europe. Using a process later known as hushing,
the Romans stored a large volume of water in a reservoir immediately above the area to be
mined; the water was then quickly released. The resulting wave of water removed overburden
and exposed bedrock. Gold veins in the bedrock were then worked using a number of

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techniques, and water power was used again to remove debris. The remains at Las Medullas and
in surrounding areas show badland scenery on a gigantic scale owing to hydraulic king of the
rich alluvial gold deposits. Las Medullas is now a UNESCO World Heritage site. The site
shows the remains of at least seven large aqueducts of up to 30 miles in length feeding large
supplies of water into the site. The gold-mining operations were described in vivid terms
by Pliny the Elder in his Naturalist Historia published in the first century AD. Pliny was a
procurator in Hispania Terraconensis in the 70's and must have witnessed for himself the
operations. The use of hushing has been confirmed by field survey
and archaeology at Dolaucothi in South Wales, the only known Roman gold mine in Britain.
The modern form of hydraulic mining, using jets of water directed under very high pressure
through hoses and nozzles at gold-bearing upland paleo gravels, was first used by Edward
Matteson near Nevada City, California in 1853 during the California Gold Rush.[3] Matteson
used canvas hose which was later replaced with crinoline hose by the 1860s.[4] In California,
hydraulic mining often brought water from higher locations for long distances to holding ponds
several hundred feet above the area to be mined. California hydraulic mining exploited gravel
deposits, making it a form of placer mining.
Early placer miners in California discovered that the more gravel they could process, the more
gold they were likely to find. Instead of working with pans, sluice boxes, long toms, and
rockers, miners collaborated to find ways to process larger quantities of gravel more rapidly.
Hydraulic mining became the largest-scale, and most devastating, form of placer mining. Water
was redirected into an ever-narrowing channel, through a large canvas hose, and out through a
giant iron nozzle, called a "monitor." The extremely high pressure stream was used to wash
entire hillsides through enormous sluices.
By the early 1860s, while hydraulic mining was at its height, small-scale placer mining had
largely exhausted the rich surface placers, and the mining industry turned to hard rock
(called quartz mining in California) or hydraulic mining, which required larger organizations
and much more capital. By the mid-1880s, it is estimated that 11 million ounces of gold (worth
approximately US$7.5 billion at mid-2006 prices) had been recovered by hydraulic mining in
the California Gold Rush.

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2.2.2 1850:-
High-pressure vessels and pumps became affordable and reliable with the advent of steam
power. By the mid-1850s, steam locomotives were common and the first efficient steam-driven
fire engine was operational.[12] By the turn of the century, high-pressure reliability improved,
with locomotive research leading to a six fold increase in boiler pressure, some reaching
1600 psi (11 MPa). Most high-pressure pumps at this time, though, operated around 500–
800 psi (3–6 MPa).
High-pressure systems were further shaped by the aviation, automotive, and oil industries.
Aircraft manufacturers such as Boeing developed seals for hydraulically boosted control
systems in the 1940s,[13] while automotive designers followed similar research for hydraulic
suspension systems.[14] Higher pressures in hydraulic systems in the oil industry also led to the
development of advanced seals and packing to prevent leaks.[15]
These advances in seal technology, plus the rise of plastics in the post-war years, led to the
development of the first reliable high-pressure pump. The invention of Marlex by Robert Banks
and John Paul Hogan of the Phillips Petroleum company required a catalyst to be injected into
the polyethylene.[16] McCartney Manufacturing Company in Baxter Springs, Kansas, began
manufacturing these high-pressure pumps in 1960 for the polyethylene industry.[17] Flow
Industries in Kent, Washington set the groundwork for commercial viability of water jets with
John Olsen’s development of the high-pressure fluid intensifier in 1973,[18] a design that was

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further refined in 1976.[19] Flow Industries then combined the high-pressure pump research
with their water jet nozzle research and brought water jet cutting into the manufacturing world.

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2.2.3 1935:-
While cutting with water is possible for soft materials, the addition of an abrasive turned the
water jet into a modern machining tool for all materials. This began in 1935 when the idea of
adding an abrasive to the water stream was developed by Elmo Smith for the liquid abrasive
blasting.[20] Smith’s design was further refined by Leslie Terrell of the Hydro blast Corporation
in 1937, resulting in a nozzle design that created a mix of high-pressure water and abrasive for
the purpose of wet blasting.[21] Producing a commercially viable abrasive water jet nozzle for
precision cutting came next by Dr. Mohamed Hashish who invented and led an engineering
research team at Flow Industries to develop the modern abrasive water jet cutting
technology.[22] Dr. Hashish, who also coined the new term "Abrasive Water jet" AWJ, and his
team continued to develop and improve the AWJ technology and its hardware for many
applications which is now in over 50 industries worldwide. A most critical development was
creating a durable mixing tube that could withstand the power of the high-pressure AWJ, and
it was Boride Products (now Kennametal) development of their ROCTEC line of
ceramic tungsten carbide composite tubes that significantly increased the operational life of the
AWJ nozzle.[23] Current work on AWJ nozzles is on micro abrasive water jet so cutting with
jets smaller than 0.015 inch in diameter can be commercialized

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2.2.4 1990:-
As water jet cutting moved into traditional manufacturing shops, controlling the cutter reliably
and accurately was essential. Early water jet cutting systems adapted traditional systems such
as mechanical pantographs and CNC systems based on John Parsons’ 1952 NC milling
machine and running G-code.[24] Challenges inherent to water jet technology revealed the
inadequacies of traditional G-Code, as accuracy depends on varying the speed of the nozzle as
it approaches corners and details.[25] Creating motion control systems to incorporate those
variables became a major innovation for leading water jet manufacturers in the early 1990s,
with Dr John Olsen of OMAX Corporation developing systems to precisely position the water
jet nozzle[26] while accurately specifying the speed at every point along the path,[27] and also
utilizing common PCs as a controller. The largest water jet manufacturer, Flow International
(a spinoff of Flow Industries), recognized the benefits of that system and licensed the OMAX
software, with the result that the vast majority of water jet cutting machines worldwide are
simple to use, fast, and accurate.[28]

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CHAPTER 3
3.1 Working:-
At its most basic, water flows from a pump, through plumbing and out a cutting head. It is
simple to explain, operate and maintain. The process, however, incorporates extremely
complex materials technology and design.
To generate and control water at pressures of 87,000 psi requires science and technology not
taught in universities. At these pressures a slight leak can cause permanent erosion damage to
components if not properly designed.
Thankfully, the water jet manufacturers take care of the complex materials technology and
cutting-edge engineering. The user need only be knowledgeable in the basic water jet operation.
Flow machines are designed to operate as both pure and abrasive water jets. A pure water jet
is used to cut soft materials, and within just 2 minutes the very same water jet can be
transformed into an abrasive water jet to cut hard materials. With any type, the water must first
be pressurized.
Fig 3.1 horizontal water jet cutter

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3.1.1 High pressure water jet cutting:-
Water is pressurized to very high pressures, in excess of 50,000 psi. This pressurization is
accomplished with the use of pumps of various designs, discussed next in this chapter.
The high pressure water is transported through a series of stainless steel tubes to a cutting
head. Depending upon the material being cut, the cutting head can be either a "pure water
cutting head" or an "abrasive cutting head."
In the cutting head, the high pressure water is forced through a small diameter orifice. The
diameter of this orifice is anywhere from 0.004" to 0.020". This step converts the pressure of
the water jet stream into speed. We go from potential energy to kinetic energy. Coming out of
the orifice, the water jet stream is moving at 2200 mph or faster. Higher pressure results in
higher speed. Smaller diameter orifices yield a faster water jet stream, but also a stream with
less kinetic energy since there is not as much water available to accelerate abrasive grains to
full speed.
In a pure water cutting head, the water immediately exits the cutting head after passing through
the orifice. The speed and power of the water jet stream is enough to cut soft or thin materials
like foam, rubber, soft wood, plastics, carpet, food, car headliners, circuit boards and more.
In an abrasive cutting head, a very hard abrasive, typically garnet, is fed into the water jet
stream. The abrasive particles are accelerated to near the speed of the water jet stream. This
gives the abrasive particles much power. The abrasive water jet stream now travels down
through an abrasive nozzle, or mixing tube, approximately 3 inches long with an inner diameter
of between .030" and 0.050". The mixture of water and abrasive exits the abrasive nozzle and
will cut hard materials like metals, stone, acrylic, ceramic, composites, phenolic and porcelain.
A CNC control will move the cutting head in up to 6 axes of motion to cut the targeted work
piece.

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3.2 Types of pumps:-
3.2.1 Intensifier
Intensifier pumps are called intensifiers because they use the concept of pressure intensification
or amplification to generate the desired water pressure.
If you apply pressure to one side of a cylinder and the other side of the cylinder is the same
surface area, the pressure on the other side will be the same. If the surface area of the smaller
side is half, then the pressure on that side will be doubled. Generally with intensifier pumps
there is a 20 times difference between the large surface area (where the oil pressure is applied)
and the small surface area (where the water pressure is generated). The following picture shows
this concep
Ultimately, there must be a restriction in the flow of water in order for the pressure to be
generated. This restriction is generated by the orifice in the cutting head. Pressure is maintained
until the orifice diameter exceeds the limits for water output of the pump.
For very small diameter orifices, in order to maintain pressure, the pump only needs to cycle
very slowly to maintain pressure. As the orifice gets larger, the pump must work faster to
maintain pressure and water flow. If the orifice gets too large, the pump tries to cycle too fast
for the design specification. An "over stroke" situation is sensed by the control and the pump
is stopped with an error message.
If there are leaks in the water circuit between the pump and the cutting head, this can also result
in a pump "over stroke" situation. The leaks effectively rob water available to go to the cutting
head. The same as putting in too large of an orifice, the pump runs faster to maintain pressure
until it reaches its limit.
Typically, intensifiers stroke at around 50 - 60 strokes per minute when working at full capacity
fig 3.2 Intensifier pump

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3.2.2 Direct Drive
A direct drive pump works like a car’s engine. A motor turns a crankshaft attached to 3 or more
offset pistons. As the crankshaft turns, the pistons reciprocate in their respective cylinders,
creating pressure in the water. Pressure and flow rate are determined by how fast the motor
turns the crankshaft. Direct drive pumps cycle much faster than intensifiers, on the order of
1750 revolutions per minute. Direct drive pumps generally are found in lower pressure
applications (i.e. 55,000 pounds per square inch and under). Maintenance on the direct drive
pump tends to take longer than an intensifier pump. Direct drive pumps can only run more than
one cutting head only if all cutting heads are cutting the same part at the same time. With an
intensifier pump, you could have cutting heads on multiple machines, cutting different parts,
cycling the various cutting heads on and off in any sequence. The intensifier pump will need
to only vary its stroke rate accordingly to maintain flow and pressure.
Fig 3.3 direct drive pump

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3.3 Principles of water jet cutting
There are two types of water jet cutting processes; pure water cutting, in which the cutting is
performed using only an ultra-high pressure jet of clean water, and abrasive water jet cutting
in which an abrasive (typically garnet) is introduced into the high pressure stream.
Pure water cutting can be employed to profile a huge variety of materials, these will typically
be 'soft' materials such as gaskets, rubber, foam & plastics. Filtered tap water is fed into an
intensifier pump where it is pressurised to (typically) 60,000psi. This ultra-high pressure water
is forced through a tiny (0.15mm) orifice jewel which is normally manufactured from sapphire.
This has the effect of focusing the beam of water into a fine, accurate stream travelling at speeds
of up to 900m/sec, capable of accurate cutting of a wide range of soft materials.
In order to cut 'harder' materials or any material containing glass or metal, then abrasive water
jet cutting would be employed. The principles of abrasive water jet cutting are similar to pure
water jet cutting, but once the stream has passed through the orifice it enters a carbide nozzle.
Within this nozzle is a mixing chamber within which a partial vacuum is created as the water
passes through. Garnet is introduced under gravity into the nozzle and the partial vacuum
within the mixing chamber has the effect of dragging the abrasive into the water stream to
create a highly abrasive cutting jet. Abrasive cutting would typically be used on materials such
as stainless steel, aluminium, stone, ceramics & composite materials.
Fig3.4 mouthpiece of jet
In both processes the head is controlled by a CNC controller, this offering great accuracy and
repeatability. The CNC controller is programmed by first drawing the part to be manufactured
using proprietary software, and then converting this drawing into a G code format – CNC
language.

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Fig 3.5 vertical water jet
Water jet cutting is a cold grinding or cutting process. It combines the advantages of laser –
precision – with those of water: water jet cutting is thermoneutral. In addition to laser cutting,
water jet cutting is becoming increasingly important in Switzerland and Germany. No thermal
stresses occur with water jet cutting. The microstructure of the material and the material
strength remain. There are no cures, distortions, dripping slag, melting or toxic gases.
In all processes, the cutting heads with the focusing nozzles are integrated in a guiding machine
(robot, 2D or 3D portal). The controlled CNC axes enable 2D, 2.5D or 3D cutting processes.
These processes can cut almost all materials – hard like steel and glass, but also fragile and
extremely soft materials – without stress forces. Water jet cutting has three principles: the pure
water jet principle “WJ”, the abrasive water jet principle “AW” and the suspension jet principle,
which is still at development stage.

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3.3.1 Water jet cutting with pure water:-
With pure water jet cutting “WJ”, a pure water jet with a diameter of 0.1 mm cuts the material
at up to three times the speed of sound (at speeds of up to 200 m/min). These materials include
textiles, elastomers, fibers, thin plastics, food, paper, cardboard, leather, thermoplastic
materials or food. The water is pressurized to 1,000–6,000 bar (standard approximately 3,800
bar). After flowing through a high-pressure needle valve, the water enters a 200 mm long and
3 mm in diameter wide collimation tube (calming section). It is then pressurized by a water
nozzle or a dynamic pressure nozzle and accelerated. The jet speed varies according to
geometry and pressure. The small diameter of the water nozzle produces a very high local
energy density, which remains constant on a relatively long section in the direction of the water
jet and cuts cleanly and accurately when hitting the material.
Fig3.6 half section view of water jet

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3.3.2 Water jet cutting with abrasives:-
With abrasive water jet cutting, compact and hard materials such as metals (including steel),
hard stone, glass (including bullet-proof glass) and ceramic are separated. Before the
concentrated jet of water hits the material, a cutting material of the finest grain size (abrasive)
is added in the required dose in a mixing chamber, which ensures micro cutting. The water
serves as an accelerator for the abrasive particles and hits the material with an impact speed of
800 m/s, thereby removing it with precision. Until the water jet is produced, abrasive water jet
cutting is identical to pure water jet cutting. The difference is that the pure water jet is no longer
used just for cutting, but as a carrier material for the abrasive particles. The pure water jet flows
into a mixing chamber, into which the abrasive particles are then introduced. At the end of the
mixing chamber is the focusing tube, in which the abrasive grains in the water jet are
accelerated and confined to a specific cross-section.

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3.3.3 Water jet cutting with suspension jet
With the suspension jet principle or water abrasive suspension jet cutting, a pre-prepared
mixture of abrasive particles and water is discharged under high pressure from a cutting nozzle.
However, the abrasive agent is not added at the nozzle but is pressurized under the exclusion
of air. Therefore, a water-abrasive mixture (a suspension) is expelled from the cutting nozzle
under high pressure. This enables higher cutting performance, allows greater thicknesses and
almost all materials to be cut. However, there is a delay in the start and stop of the cutting
operation, since the abrasive feed cannot be switched on and off as rapidly as in injection
cutting. This is one disadvantage when high-precision cutting is required. The wear on the
valves and nozzles is also much larger and attainable pressures are smaller. Therefore, this
principle is only seldom used on an industrial scale.
Fig 3.7 suspension jet

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3.4 PARTS OF WATER JET CUTTER:-
3.4.1. Electric motor and hydraulic pump
The electric motor and hydraulic pump (number 1 in picture above) create the oil pressure
needed for the oil side of the intensifier. This assembly is normally in the lower portion of the
pump cabinet. The electric motor and pump are rated in HP (or kW for metric). Typical pump
sizes are 30 HP, 50 HP, 75 HP, 100 HP and 150 HP As discussed in the previous chapter, each
pump will have an associated water output volume (gallons per minute) and pressure (psi).
Again it is important to remember that HP is not necessarily an indication of pressure. A 150
HP pump doesn’t necessarily create more pressure than a 50 HP pump. Horsepower is more
directly related to water output, since more HP will be needed to create enough power to move
the piston/plunger assembly in the intensifier at the required stroke rate.
Fig3.8 Intensifier pump cabinet (150 HP)

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3.4.2. Directional control valves
One of the most important considerations in any fluid power system is control. If control
components are not properly selected, the entire system does not function as required. In fluid
power, controlling elements are called valves. There are three types of valves: 1. Directional
control valves (DCVs): They determine the path through which a fluid transverses a given
circuit. Pressure control valves: They protect the system against overpressure, which may occur
due to a sudden surge as valves open or close or due to an increase in fluid demand. 2. Flow
control valves: Shock absorbers are hydraulic devices designed to smooth out pressure surges
and to dampen hydraulic shock. In addition, the fluid flow rate must be controlled in various
lines of a hydraulic circuit. For example, the control of actuator speeds can be accomplished
through use of flow control valves. Non-compensated flow control valves are used where
precise speed control is not required because the flow rate varies with pressure drop across a
flow control valve. It is important to know the primary function and operation of various types
of control components not only for good functioning of a system, but also for discovering
innovative methods to improve the fluid power system for a given application. 1.2Directional
Control Valves A valve is a device that receives an external signal (mechanical, fluid pilot
signal, electrical or electronics) to release, stop or redirect the fluid that flows through it. The
function of a DCV is to control the direction of fluid flow in any hydraulic system. A DCV
does this by changing the position of internal movable parts. To be more specific, a DCV is
mainly required for the following purposes:  To start, stop, accelerate, decelerate and change
the direction of motion of a hydraulic actuator.  To permit the free flow from the pump to the
reservoir at low pressure when the pump’s delivery is not needed into the system.  To vent the
relief valve by either electrical or mechanical control.  To isolate certain branch of a circuit.
2 Any valve contains ports that are external openings through which a fluid can enter and exit
via connecting pipelines. The number of ports on a DCV is identified using the term “way.”
Thus, a valve with four ports is a four-way valve A DCV consists of a valve body or valve
housing and a valve mechanism usually mounted on a sub-plate. The ports of a sub-plate are
threaded to hold the tube fittings which connect the valve to the fluid conductor lines. The valve
mechanism directs the fluid to selected output ports or stops the fluid from passing through the
valve. DCVs can be classified based on fluid path, design characteristics, control methods and
construction

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Fig 3.9 Directional Control Valve
3.4.3. Intensifier
The intensifier proper (3 in Figures 4 and 2) consists of the hydraulic cylinder (4), high pressure
cylinders (7), and check valves (8) and end caps (9). Not visible from the outside are the piston
and plunger.
Fig 3.10 Intensifier
3.4.4. Hydraulic cylinder
The hydraulic cylinder (4 in Figures 2 and 5) houses the piston and is the area where the
hydraulic oil does its work. The directional control valves control the flow of oil into and out
of each side of the hydraulic cylinder.

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At each end of the hydraulic cylinder is an end plate that is used to connect the hydraulic
cylinder to the high pressure cylinder. The two end plates for the hydraulic cylinder are
connected and pulled tightly in place with 4 tie rods and bolts.
Fig 3.11 Hydraulic cylinder
3.4.5. Piston
The piston (number 5 in Figures 2 and 6) is the larger diameter cylindrical part located within
the hydraulic cylinder (4 in Figures 2 and 5). The piston effectively splits the hydraulic cylinder
into a left side and a right side. Oil cannot pass from one side to the other past the piston. It
must exit and enter the hydraulic cylinder through the hoses attached to the directional control
valve. The hydraulic oil pressure is exerted onto either side of the piston in an alternating
fashion so that a back-and-forth movement of the piston and plunger assembly is generated.

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Fig 3.12 Piston (5) and plunger (6) assembly
3.4.6. Plunger
The plungers (6 in Figure 7) are the two smaller diameter shafts that are connected to each side
of the piston. The attachment point is inside of the hydraulic cylinder. The other ends of the
plungers extend into the left and right high pressure cylinders. Seals are placed around the
plunger shaft to keep oil from seeping into the water side of the pump, and vice versa. The
plungers are made out of either stainless steel, or, more recently, ceramic. Ceramic is used
because of its ability to handle heat and high pressure with little thermal expansion.
Fig 3.13 Ceramic plunger

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3.4.7. High pressure cylinder
The two high pressure cylinders (7 in Figures 8 and 2) are where the water is pressurized. They
are usually referred to as "left hand side" and "right hand side." The high pressure cylinders are
machined out of very thick stainless steel and treated in order to withstand the extreme
pressures they are put under on a continual, cyclical basis.
Fig 3.14 High pressure cylinder (7)
3.4.8. Check valve
There is one check valve (number 8 in Figures 10 and 8) at the end of each high pressure
cylinder at the end opposite from the hydraulic cylinder. The check valve allows fresh water to
enter the high pressure cylinder and high pressure water to exit the intensifier. The check valve
is designed to only let water flow in one direction. Fresh water comes in though channels
machined in the sides and exits through one or more holes in the face of the valve. Various
seals, poppets and springs are used to maintain this water flow. Over several hundred hours
these components will wear, allowing pressurized water to flow out the water inlet path, or
allowing pressurized water to seep back into the high pressure cylinder. The symptoms and
diagnosis of these various situations will be discussed later in the "Maintenance" chapter.

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Fig 3.15 View of upper portion of intensifier cabinet
Fig 3.16 Check Valve Body cross-section
3.4.9. End Cap
The end cap (number 9 in Figures 11 and 2) is either a cylindrical or square item. The
cylindrical version screws onto the output end of the high pressure cylinder. The square type is

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held in place with tie rods and bolts. The end cap has a hole in the center for the check valve
and outlet body. It will also have a connection point for the incoming fresh water. The water
flows through holes machined through the cap to line up with inlet holes in the check valve
Fig 3.17 fillets caps

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3.4.10. High pressure tubing
High pressure 304 or 316 stainless steel tubing (number 10 in Figure 11) is attached to the
outlet of each check valve. Common outer diameters are 0.25", 0.313", 0.375" and 0.563".
Inner diameters range from 0.062" to 0.312". There is usually a flexible protective covering
around the tube.
The high pressure tubing from the left hand high pressure cylinder will join together at some
point with the high pressure tubing from the right hand cylinder. The high pressure tubing
carries the pressurized water to the pressure attenuator. Additional high pressure tubing will
channel the high pressure water to the cutting head.
The length, number of bends and other obstructions to flow (e.g. hand valves) in the high
pressure tubing path must be taken into consideration when designing a high pressure water jet
system. Pressure will drop with each bend in the tubing. Also, as the distance between the pump
and the cutting head increases, internal friction of the water as it drags against the inner walls
will generate heat resulting in a loss of water pressure. This topic will be discussed in more
detail in the Chapter 5 "Pressure Drop in Tubing."
3.4.11. Pressure attenuator
The pressure attenuator (number 11 in Figures 13 and 2) smoothest out variations in pressure
after the high pressure water has exited the intensifier. With each reversal of cycle of the
intensifier, there is a slight delay in the increase of water pressure in the opposite high pressure
cylinder. This delay is due to: 1) reversal of motion where instantaneous velocity at the end of
the stroke equals zero, and 2) mechanical delays of reversal. All of these factors can result in a
drop in water pressure. Some manufacturers do use proprietary technology to reduce this
pressure drop, which we suggest you investigate when selecting a pump. Generally, if a 50 HP
pump can sustain a 0.014" orifice at 60,000 psi continuous operating pressure, the implication
is that this hydraulic pressure drop challenge will have been addressed.
Figure 14 shows the pressure fluctuations in the high pressure water line prior to the pressure
accumulator. This shows a pressure change from high to low of almost 22,000 psi. So, for a
60,000 psi system, the high pressure water would be going from 60,000 psi to 40,000 psi after
every stroke of the intensifier.

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If this pressure fluctuation were not smoothed out by the pressure attenuator, cutting results at
the work piece would be undesirable. There would be a significant line in the part with every
stroke of the intensifier. Recall that any change in pressure results in a change in speed of the
water jet stream at the cutting head. This change in speed changes the speed at which the
abrasive particles are moving and, therefore, the amount of force they will impact on the work
piece. Lower pressure leads to less speed of the water which leads to less force of the abrasive
which leads to slower cutting, or rougher edge quality.
Fortunately the pressure attenuator smoothest out these pressure spikes so that the water at the
cutting head maintains a steady pressure, speed and cutting power
Fig3.18 Pressure Attenuator
Fig3.19 Pressure fluctuation prior to accumulator

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3.4.12. Inlet water
Prior to entering the pump cabinet, water may have to be treated to get the water within the
water jet manufacturer’s specifications. Within the pump cabinet, usually in the lower portion,
the water will typically go through one or more final filters just prior to entering the intensifier
(number 12 in Figures 15 and 2).
The inlet water must be able to maintain a specified flow rate and pressure to ensure that the
intensifier receives enough water. Incoming water must also meet certain requirements with
respect to Total Dissolved Solids (TDS), pH, organic matter, temperature, etc. Poor water
quality will result in drastically reduced high pressure component life (i.e. anything the high
pressure water comes in contact with). Different pump manufacturers require different inlet
water pressures, with some needing as little as 30 psi, and others mandating a water pressure
booster pump to maintain 100 psi. Water quality will be discussed in more detail in the chapter
4 "Water QUILITY
Fig 3.20 water inlet system

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3.5 Controls and PLC
The controls and PLC (not pictured) control the valves in the hydraulic circuit to determine the
pressure and flow of the hydraulic oil to and from the intensifier. Various sensor and proximity
switches can also be integrated into the controls to monitor the entire pump to verify things like
stroke rate, oil temperature and pressure, inlet water pressure and flow rate and more. This
capability makes working with and troubleshooting the modern day intensifier much easier.
3.5.1 On-Off Valve
The pneumatic On-Off valve controls the flow of water to the cutting head. The On-Off valve
at the cutting is "normally closed." That is, when there is no compressed air supplied to the On-
Off valve, a needle fits tightly against a seat to stop any high pressure water from getting to the
cutting head. When compressed air is supplied to the On-Off valve (i.e. "tool on" command
from the control), the needle is forced up from its seating location and the high pressure water
can flow through the orifice to the cutting head.
In, or near, the high pressure pump cabinet is another On-Off valve that works in tandem with
the On-Off valve at the cutting head. The On-Off valve in the pump is typically called the
Safety Relief valve. This Safety Relief valve in the pump is "normally open." This valve will
stay open when there is no air supplied to it. When the On-Off valve at the cutting head closes
("tool off" command by control or no power to the system), the Safety Relief valve in the pump
will open, relieving all water pressure from the high pressure tubing. When the "tool on"
command is issued by the control, the Safety Relief valve closes so that all high pressure water
will go to the cutting head. Note, not all manufacturers of new pumps have the Safety Relief
valve as standard. We strongly suggest you ask your pump manufacturer if they supply this
standard, and when it is activated. Again, some pump manufacturers will only activate the
Safety Valve when an E-Stop is pressed; when the pump stops, high pressure lines are still
pressurized.
Both of these On-Off valves must be in good working order to protect against accidental high
pressure water discharge at the cutting head that could severely injure someone working on or
near the cutting head or any of the high pressure lines. Periodic replacement of the needle, seat
and associated parts is required to maintain these valves.

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3.6 Abrasive feeding system
3.6.1 Pressurized Bulk hopper:-
Abrasive is transported via tubing and pressure from a large bulk hopper located near the water
jet cutting system to a mini-hopper near the cutting head. Bulk hoppers will normally hold
anywhere from several hundred pounds of abrasive to 2200 pounds. If you are cutting with
one head and 1.4 pounds per minute of abrasive, then you are consuming about 84 pounds per
hour. An 1100 pound hopper would last about 13 hours of operation. This would mean that the
machine could run for well over a shift before it needed to be refilled. Most water jets are
provided with approximately 600 pound hoppers, which would equate to about 7 hours of
operation. So, at least once during an 8 hour shift the hopper would need to be reloaded. The
costs associated with the additional downtime over the course of a year should be evaluated.
Fig 3.22 bulk hopper
3.6.2 Mini-hopper
A mini-hopper is typically mounted near and above the cutting head. Most of these mini-
hoppers allow for a gravity feed of abrasive down to the cutting head. Many mini-hoppers
control the amount of abrasive that can go down to the cutting head with the use of a slide with
different size holes in it. The operator can change the position of the slide to change the amount
of abrasive to the cutting head.
A recent advance in technology is remote CNC-control of the amount of abrasive released from
the mini-hopper. Having this capability allows for optimum feeding of abrasive to the cutting
head in relation to the water pressure at the pump for the following desirable capabilities:

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 Piercing of fragile materials like glass or stone. Typically a lower water
pressure will be used with a smaller amount of abrasive
 Changing abrasive amount for different abrasive nozzle sizes to optimize
part cost. This can be done automatically if the mini hopper is set up to do
this.
Fig 3.23 abrasive material feeding

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CHAPTER 4
CONCLUSION:-
As a conclusion, the experiment that have been carried out were successful, even though the
data collected are a little bit difference compared to the theoretical value. The difference
between the theoretical value and the actual value may mainly due to human and servicing
factors such as parallax error. This error occur during observer captured the value of the water
level. Besides that, error may occur during adjusting the level gauge to point at the white line
on the side of the weight pan. Other than that, it also maybe because of the water valve. This
error may occur because the water valve was not completely close during collecting the water.
This may affect the time taken for the water to be collected. There are a lot of possibilities for
the experiment will having an error. Therefore, the recommendation to overcome the error is
ensure that the position of the observer’s eye must be 90° perpendicular to the reading or the
position. Then, ensure that the apparatus functioning
perfectly in order to get an accura

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REFERENCE
1.http://www.cee.mtu.edu/~dwatkins/ce3600_labs/impact_of_jet.pdf
2. http://www.eng.ucy.ac.cy/EFM/Manual/HM%2015008/HM15008E-ln.pdf
3.http://staff.fit.ac.cy/eng.fm/classes/amee202/Fluids%20Lab%20Impact%20of%20a%20Jet.
pdf
4. WIKIPEDIA
5. http://www.wardjet.com/water jet-university

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