High Pressure Water Jet Technology

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Running head: HIGH PRESSURE WATER JET TECHNOLOGY 1

HIGH PRESSURE WATER JET TECHNOLOGY

Name of Researcher

Name of Institution

Date


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HIGH PRESSURE WATER JET TECHNOLOGY

Introduction

The field of engineering has experienced numerous defining innovations in the recent

five decades. The field of cutting and molding shapes has seen the most of these advances. The

use of water as a molding and cutting agent was not feasible for a long term in the pre- industrial

revolution and post industrial revolution periods. In the early 1960s water became an integral

part of engineering though it had limited applications in cleaning and drainage systems.

The limitations of water as a useful tool for modeling lay squarely on the constraints that

existed in the engines that generated pressure. This limitation was overcome largely when more

powerful engines were invented. These engines could generate Mega Pascals of pressure thereby

beginning the unrelenting progress of using jet water as an integral component of the cutting and

modeling industry.

High pressure water technologies have found massive adoption in the market due to the

high efficiency levels that come with water systems. The levels of safety experienced by the

users of the high pressure water systems are unrivalled in the field of engineering. Another

defining advantage experienced by water based cutting systems is the capability to avoid the

processes of wear and tear that are inherent in all other methods of cutting. For instance, metal

based cutting systems experience very high wear and tear rates to the point that replacements

cover more than 40% of the net revenue of the process under study. The fire based systems of

cutting pose very high risks of safety to the operators, material and the equipment.

It is with this zero percent safety and efficient background that this paper seeks to keenly

study the high pressure water jet technology. The study will seek to highlight the reasons behind

the fast adoption of water technologies in the building, molding and cutting industry.


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The engineering field envisions that a great number of related engineering fields will

adopt this technology. The oil exploration and mining industry stands a great chance of adopting

this technology because high pressure water jet technology offers numerous unrivalled

advantages.

Physical background of processes

The Continuous High Pressure Water Jet.

The formative adoption of the water based system of cutting involved the use of water

blaster as the main source of pressure for the system. The water blaster could generate pressure

levels reaching 20Kpsi. This blasting can be achieved using a triplex pump that has compresses

water in the available space between the feeding pipe and the releasing nozzle. The lining of the

nozzle gun is made of hard steel which has the characteristic of resisting the erosive effect of the

water jet. The high pressure water flows at high velocity through the tiny nozzle towards the

target material.

An analysis of this process indicates that addition of abrasives in the water results in a

considerably powerful nozzle jet. The reason behind this is that the water jet that is loaded with

abrasives is able to overcome the air drag that has a decelerating effect on the jet of water. With

such a directed jet, the material is easily eroded under the influence of micro level erosion using

the abrasive particles.

There exists a major defining difference between the high power water jet technology

(HPWJ) and the other metal based technologies available in the field of engineering. In the

HPWJ technologies heat is not part of the resultant products. This is the case because water acts

as both the erosive agent as a lubricant. Contact does play a major part as related to impact that is


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utilized in HPWJ technologies. This is the main characteristic in the water based system that has

fuelled the speed of adoption.

Classification of water jets under the High Pressure Water jet system

Water jets can be classified as follows: the plain water jet and the abrasive assisted water

jet.

Plain water jet

The plain water jet uses pure water without addition of any chemical or element to

hasten the process of surface erosion.

Abrasive water jet

The abrasive assisted water jet uses many different types of metallic based abrasives to

achieve impact and consequently the cutting of the material. The plain water jet is mainly used in

cutting soft materials that include soft rubber, cardboards, foil, form and soft gasket. On the other

hand the abrasive assisted water jet finds numerous applications in areas like cutting titanium,

aluminium, stone copper stainless steel, ceramics, marble, glass and granite.

The mostly used abrasive material is garnet sand. This material is readily available and it

is comparatively harder when compared to other commonly used materials in abrasive assisted

water jet applications.

Plain water jet has taken charge of the light duty field of cleaning while the other heavy

duty engineering tasks like civil engineering makes use of abrasive assisted water jet to remove

paint during renovation exercises. Finishing of rough walls also applies the abrasive assisted

water jet technology.

An upcoming field of application for the water based jet system is the area of oil

extraction. Studies indicate that HPWJ offers a very safe operating environment with minimal


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effect on the rate of global warming. HPWJ is suitable in the oil industry because it has the

capabilities of achieving very slim lateral holes from the surface to the oil well without

generating considerable heat.

Factors that affect water cutting performance

Researchers have taken time to document several factors that play part in the

effectiveness of the HPWJ technology. Among the key factors involved in the cutting

performance we have:

Water jet pressure

The depth of the cut initiated by a water jet is directly proportional to the initial pressure

of the water jet. This relation holds only in the region after the system has achieved critical

pressure. With a threshold pressure in sight, it is vital for any user of HPWJ technology to clearly

know the operating pressures of the system. Critical pressure is heavily dependent on the target

material for cutting. The erosive characteristic of the material determines the critical pressure of

the water jet. In cases where the material is considered a soft material the abrasive additions

cannot be considered in the process of determining the critical pressure.

Size of the abrasives

Another factor that hugely influences the effectiveness of the water jet is the size of the

added abrasives. Following closely with the size of the nozzle, the size of the abrasive particles

influences the depth of cut. Normal operations involve the use of size particles that are 30% the

size of the nozzle on the water gun.

Abrasive rate of flow

In abrasive assisted water jets, the performance of the water jets heavily depends on the

rate of flow of the abrasive particles. Studies indicate that the faster the abrasive particles hit the

target surface, the higher the impact felt. The user of the system should therefore optimize the


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system to ensure that the nozzle is able to release the optimal number of abrasive per unit time

for an effective cutting.

The speed at which the cutting of metals is achieved can be controlled by varying several

parameters that accompany the waterjet seup. Among these factors we have, abrasive

parameters, parameters related to hydraulics, mixing nozzle parameters and lastly, cutting

parameters.

Abrasive Parameters.

Abrasive parameters include the density of the material used as an abrasive, the shape of

the material and the hardness of the material. Another angle of the abrasive material looks at the

size of the pebbles together with how fast they exit the nozzle of the orifice. the speed at which

the abrasive materials are able to leave the nozzle also depends on the method in which the

abrasive materiala are fed into the mixing chamber. The final factor that affects cutting using

waterjet assisted method relates to the condition of the abrasive material.

Hydraulic Parameters

The cutting rate has been found to be reliably controlled by the diameter of the waterjet

orifice. This works closely with the pressure at which the water and the abrasives are supplied to

the orifice setup for release.

Mixing opening parameters

The dimensions of the chambers that facilitate the mixing of the water and the abrasives

play a vital role in the final rate of cutting that results. Couple with the orifice dimensions is the

material that is used for making the nozzle. The nozzle needs a hard material of the precision

measurements that should result in the target material.

Cutting Parameters


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The parameters that closely influence the cutting process include the rate at which the

operator initiates traverses on the material. This in turn affects the number of passes made.

Another side of the cutting parameter is the standoff distance that relates to the distance between

the nozzle and the material under experiment or cutting. The last item under consideration in the

category of cutting parameters is the angle of cutting. The quality of the final cut is hinged to the

angle at which the orifice targets the material.

When dealing with abrasive water jets there are two modes of operation that come up.

Firstly we have the cutting wear mode and secondly we have deformation wear mode. The

cutting wear mode utilizes shallow angles in effecting the impact of the abrasive particles. On the

other hand the deformation wear makes use of larger angles than those experienced in the cutting

wear mode. A considerable difference therefore exists in the two modes because the cutting wear

mode results in an interface that resembles a steady state cutting while the large angle cutting

results in a rather unsteady finish. Both these modes play a vital part in the final result of the

work piece. The contribution is relative to the rate of traversing of the work piece. This makes it

a user controllable factor.

The expression below shows the respective contribution of the two modes to the depth of

cut in the material. The effect that the depth has on the velocity of the particle has been

neglected.

(1)The first term in the equation represents the contribution of cutting wear while the second

term represents the contribution by deformation wear.

In the above equation,

v is the velocity of the jet


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is the flow stress of the jet

is the material specific energy

is the diameter of the abrasive water jet.

c is a constant.

Studies of high pressure abrasive assisted water jet technology indicate that cutting wear

mode terminates at

(2)

When the critical traverse rate is surpassed, the deformation wear rate fully covers the

cutting process because the cutting wear proportion will be negligible.

An advanced expression that includes the braking effect of the depth on the particle

velocity is given by:

(3) Having and cf= 0 and substituting in equation (1) we have, (4)


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Taking N4 as the ratio of the specific energy of the material to the jet flow stress we

can further equation 4 into

(5)

Though the abrasive assisted water jet technology seeks to provide a simple and

predictable platform, there are numerous factors that hinder the achievement of this goal. The

dynamic properties of the material in use may not be readily available. The flow stress property

and the toughness property can be approximated and used in the process of establishing optimal

operation conditions. This hindrance is still under study in many research centers involved in the

upcoming water jet technologies.

Another problem that has faced efforts that are interested in getting the optimal

conditions under which the abrasive assisted water jet technology operate is the establishment of

the particle velocity. There is very little effort that has been made towards establishing methods

that would facilitate the acceleration of the particles and the water jet. The mixing chambers

from which the jet originates have not seen recent improvements because efforts in the field of

water jet technology have concentrated largely on the accelerating effect of the water on the

abrasive particles. The problem to this conventional position on the velocity of the abrasive

particles is that, it is very hard for the system users to predict the velocity of the particles when

numerous methods of mixing are utilized. This is also the case that results if other complex

parameters of hydraulics are considered.

The level of advancements in the abrasive assisted water jet technology indicates that the

above problems are subject to disappear because experiments have shown an identical trend in

different target materials. With this background there is a great likelyhood of establishing a

common strategy that will facilitate an approach to common industrial materials. A consequent


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result of this finding is that, common materials can be adjusted in properties so that simulations

of different materials can be achieved.

Inclusion of further results from many other experiments will facilitate acquisition of

optimal parameter that will set pace for best results.

Pulsed Water Jet

The pulsed water jet is an advanced form of the continuous pressure water based cutting

system. The implementation of the pulsing water jets is achieved by modulating the frequency,

amplitude, and other vital components of the waveform characteristics so as to influence and

control the acoustic generator.

The physical make up of the pulsed water jet system has an additional system that

induces the change in pulses to the conventional water bluster system.

A major advantage that arises from the percussive implementation is that the system is

able to use less water to achieve deeper cutting than those achieved in the abrasive assisted

system. The principle behind this excellent operation is the presence of the water hammer effect.

This effect originates from the pulses introduced by the acoustic chamber into the water. The

system has capability of introducing longer lateral velocities because of the repeated water peaks.

This results in deeper cuts due to the stronger water heads that resists the drag of air.

The pulsed system has a continuous cyclical unloading characteristic. This arises because

of the modulating effect of the pulsed chamber. This characteristic enhances the penetration rates

achieved by this advanced system because of the effect of resonance induced in the target

system.

Why the pulsed system?


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The reason for the introduction of the percussive system is to take over the already

overstretched limits experienced by the conventional plain water and abrasive assisted water jet

systems. The conventional systems base their effectiveness on the amount of pressure induced

into the water. This strategy has various limitations that include the power limitation. In order to

achieve high pressure values, system takes up very high values of energy. In the long run the

users may render the system unreliable and uneconomical. The abrasive system on the other

hand, falls into the trap of complexity. This is majorly controlled by the size of the nozzle. The

distance of operation affects the conventional water jet systems. This is a key factor because of

the loss of lateral strength in the jet of water used in the conventional water jet system.

The percussive water jet system seeks to enhance the effectiveness exhibited by the

previous water jet systems. The percussive system seeks to alter the properties of water without

using a lot of additional materials.

In order to achieve this, the pulsed system modulates the rate at which the water jet goes

through the nozzle. This is achieved by cycling the water jet slightly more or less from its

median amplitude and frequency. A smooth waveform that results also enhances the cutting

effectiveness of the pulsed water jet system.

The result of this formulation is the bunch up of water along the jet of water. The water

bunches alternate in size from small to large as the jet flows towards the target material. This

phenomenon has an astounding effect on the hard surface that needs cutting. Because the

bunching up of the water introduces various tension and compression forces, a hard surface

easily crumbles. The reason behind this is that, the different bunches void the conventional

continuous transmission of force and substitutes it with interchanging magnitudes of force that

varies with time. There is a marked difference between the pressure of a smoothly flowing water


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jet and a bunched up water jet. The following show the constitute elements of the two pressure

values.

Where represents the density of water

V represents the velocity of the jet.

C is the acoustic wave speed

Pa is the pressure resulting from hammer effect in bunched up water.

Ps is the pressure resulting from steady fluid flow.

These impacts at the point of action offer larger cutting powers when compared to those

exhibited by the plain water and abrasive assisted systems.


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Factors that affect the pulsed water jet flow system

There are numerous variables that play part in the final quality and effectiveness of the

pulsed water jet flow cutting. A big advantage that comes with the pulsed water jet flow system

is that most variables can be manipulated by the user to achieve the best conditions.

Modulating frequency

The modulating frequency determines the number of bunches that are bound to result in

the distance between the nozzle and the target material. When the frequency of modulation is

increased the distance between successive bunches reduces. This may result in the loss of the

impact as a continuous stream of flow arises. It is recommended that a considerably high

modulating frequency is used to generate high impact bunches.

Commonly used frequencies for modulating water jets are 50KHz. This is much

dependent on the variables posed by the specific experiment or industrial scenario.

Jet amplitude

The amplitude of the jet depends largely on the modulator. This enables the system users

to achieve varying rates of flow together with varying levels of pressure. This is important when

we consider the kinetic energy held in the bunch that occurs in the water jet. The drop in the

modulation amplitude is an important characteristic in the achievement of strong magnitudes for

effective impact.

Waveform

The bunching effect relies heavily on the type and shape of the waveform under study. A

poorly controlled waveform results in a very disastrous result.


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Pulsed water jet characteristics that enhance excellent performance

The pulsed water jet system has inherent characteristics that enhance its effectiveness and

efficiency.

The force and area of impact

The force and area of impact is enhanced when we consider the pulsed and percussive

water jet systems. With a strong foundation in the modulation, the resultant bunching effect in

the water system increases the total area of action and consequently the amount of force applied.

The jet is able to achieve the effectiveness of a large diameter nozzle. This is a result of the

difference of impact between successive bunches of water. This increases the effectiveness

during cutting.

Though the percussive system exhibits strong cutting capability it is best applicable for

shallow cutting. This is a direct result of the stagnation of the used water in the depression

already created. This acts a big drawback for this system.

Initial impact

The initial impact exhibited by the percussive jet necessitates large forces of compression

on the material. The water bunches instill this effect that resembles the action of a hammer.

Velocity of water

The velocities involved are high hence a great benefit from the shearing forces. The

presence of the shear forces pushes the material to separate thereby paving way for more cutting

and draining the used water away.

The water hammer effect

The water hammer effect finds a lot of application in cutting hard materials like rocks.

Rocks have posed a big challenge to most other hydraulic based cutting systems.


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OPTIMAL EXAMPLES OF APPLICATION

The HPWJ has been used in several conventional industries and new industries in efforts

towards achieving effectiveness and efficiency of operation. In this paper we are going to study

in practical detail several applications that have utilized the water jet technology in any of its

forms.

Abrasive water jets have found numerous applications in the mechanical milling industry.

This application is largely influenced by the rapid discovery of new materials that are better

suited for the mechanical industry as compared to the conventional heavy materials. The use of

the abrasive water jets reports high levels of energy utilization because it is able to remove the

ejected materials from the surface under impact. Among the materials used in this application

include aluminium, Inconel and titanium.

A major target of the abrasive water jets is to achieve well defined geometry of slots and

a clean surface irregularity. The abrasive water jets have found numerous applications in the

areas that are difficult to access and mold together with removing residues of the materials. The

abrasive water jet has the capability of achieving depths that are computer controlled because of

the easily controllable erosion characteristic. In this light the single pass milling and the multiple

pass milling processes come into play.

Single Pass milling process.

The milling includes all the cutting processes that do not involve cutting through the

material. This means that any depths that are less than the effective thickness of the material

result in milling processes. The controlling parameter of milling processes is the rate of

generation of the kerf area. If this parameter is maximized then high quality cutting results. Other


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parameters that play a vital role in the case of milling include the rates at which the residue of the

material is removed together with the topography parameters of the material under study.

Single pass milling results in a non uniform depth of the slot created. The lateral profile

of the cut also indicates that the process is largely non uniform. These outcomes depend on the

traverse rate together with the standoff distance. This background indicates that an exercise of

control on the stand off distance and the traverse may result in better results of the milling

process.

Stand off Distance

Stand off distance determines the effective rate at which the residue of milling is removed

from the work piece. Apart from this quantitative value, the standoff distance also affects the

quality of roughness that results from any milling process. Experiments have set the optimal

standoff distances for various materials like hardened steel and aluminum. It is also evident from

experiments that the bigger the standoff distance, the smaller the rate of material residue

removal.

Traverse speed

The traverse speed also affects largely the volume of material removed from the target

material and the depth that results in the material. Studies indicate that an increase in the speed of

traversing the material reduces considerably the volume of material removed. The time T

required to mill a slot of length l and width w is:

Where u represents the traverse rate measured in mm/sec

is the measure of the instances of advances


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Studies indicate that the increase in the traverse speed reduces the effective depth of

milling. Though the traverse speed generates reduction in the rate of material removal and the

depth of milling, experiments have established that the increase in the traverse speed result in a

uniform depth.

Using a double jet nozzle raises very different results. A dual jet nozzle employs two

parallel waterjets feeding a mixing chamber. This setup seeks to enlarge the effective area

exposed to the nozzle. When this setup is used in the process of milling it is observed that

residue removal is heavily reduced. This is attributed to the inefficiency that arises from the

mixing chamber. The chamber is adjusted so that it makes use of a larger tube in the mixing

chamber. Experiments indicate that the tube for use in the bigger mixing chamber is almost ten

times the size of the tube used in the single inlet mixing chamber. In order to realize better

results when using the dual inlet setup, the nozzle must be altered so that power can be

distributed equally across the surface of the jet. A suggestion that the field is pursuing involves

the use of numerous water jets that have reduced spaces between them. another option for

realizing this includes the use of a 2-D chamber for mixing with a single orifice.

Multiple Pass Milling

In order to realize multiple notches and depths on materials there is need to make use of

the Multiple pass milling setup. Among the vital parameters for the operation of this setup we

have, high pressure levels of 170MPa. The standoff distance for this setup is about 13mm. The

setup for multiple milling is kind of complicated because of the programming that is required. In

order to realize a final shape a pattern must be fed to the controller of the multiple pass millers.

From the setup of the multiple pass miller \there are several parameters that play a vital part in

realizing quality shapes and cuts.


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Abrasive Material

Results from the multiple milling process indicate that the harder the abrasive materiall

used, the faster is the rate of residue material removal. This dictates that harder abrasives should

be used in the formative stages of cutting before the softer abrasives are used for the processes of

finishing.

Another factor that affects the final cut in multiple pass milling is the type of abrasive

material. Alternative abrasive materials give varying results when compared to the use of garnet

sand. Though Garnet sand gives faster rates of material removal, experiments indicate that better

finishing results are recorded when silica sand and glass beads are used. The effect of these

abrasive materials on the resultant depth of milling should be factored in the setup process. The

reason for this is that consecutive tries at achieving deeper cuts affects the desired texture of

surface.

Size of abrasive particles

It is evident from the experiments done using the multiple pass milling setups that finer

particles result in finer textured surfaces. This application results in a slower process because of

the reduced levels of volume removal.

Traverse Speed in Multiple Pass milling

From numerous experiments it is observed that the rate of volume removal reaches a peak

at about 0.5mm depth when using 250mm/s. the smoothest cut however was recorded o occur at

the traverse rate of 420mm/s.

The information presented in relation to the abrasive assisted water jet application

indicates that there is a lot merit that comes with the use of this technology as related to other

cutting technologies in the field. Specific merits inherent in the abrasive assisted water jet system


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includes the capsbility of the setup to mill materials that are considered to be very hard. The

abrasive assisted water jet technology also boasts of very minimal rates of deformation stresses

and thermal effects. Another specific merit of this application is the ability to accomplish

machining in many directions without the need to use heavy clamping for the pieces. A safety

advantage that comes with this system is the minimum contact that both the operator and the gun

experience with the work piece. This characteristic coupled with the minimal wear and tear to the

equipment makes the abrasive assisted water jet technology a desirable option in the field of

machining and model engineering. The technology also boasts of capabilities of implementing

advanced automation and remote control. With this features, the users of the system are able to

enjoy the benefits of convenient operation and massive energy conservation.

The rate at which the abrasive assisted water jet technology has been adopted indicates

that, numerous traditional cutting technologies may face quick replacement. Among the key

technologies that may face replacement, we have Electrical discharge machining, Electro

chemical machining and ultrasonic machining. For instance, the Electrical discharge machining

is best suited for materials that conduct electricity. This makes it a selective method that may

induce a lot of expenses when we consider the varied application that the abrasive assisted water

jet can accomplish. Another undoing for the Electrical discharge machining approach is the

initial cost of the machine together with the rate at which the machine becomes useless. The

technique is also disadvantageous when we consider the number of electrode alterations that the

operator must do in order to do a new task. The method is also criticized for introducing harder

properties in the material hence undesirable in the industry.

Another technology that may face replacement in the machining applications is the

Electrochemical machining. This method is heavily criticized for executing very slow material


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removal rates. The machine that implements this method is very expensive hence limits the

dynamic users from taking it up easily. Just like the Electrical Discharge Machining technique,

this approach only works for materials that are able to conduct electricity. This approach

demands that the users do pilot tests in order to get the best settings before implementing the

final work piece.

Chemical machining makes use of the etching process to accomplish cutting or milling.

The process comes with an inherent disadvantage of slow rates of material removal. Also the

approach has a high security risk to operators who are not well skilled. With this limitation of

skilled operators only, this approach has faced a slow adoption in the industry.

Numerous other approaches are faced by the problems of slow material removal and the

initial capital outlay that the abrasive assisted water jet technology overcomes. For instance the

electron beam machining approach requires the presence of a vacuum environment in order for

the pieces of metal to be machined. Though this method can achieve very minute diameters, the

cost of implementing the vacuum is very high for a basic operations organization.

The laser beam machining technology has taken a close leap at competing with the

abrasive assisted water jet technology. The disadvantage that faces the laser beam technology is

that it is not suitable for very thin materials. The laser beam technology does not also find easy

application because of the thermal effect and irregular finishes that accompany laser beam

machining.

USE OF WATER JET TECHNOLOGY IN CUTTING FOAM

Cutting foam has become an indispensible part of the production process in most light

weight industry. This is evident in the packaging industry where inexpensive solutions are sought

as opposed to expensive solutions. A vital characteristic of such applications is that the


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packaging material should precisely follow the shape of the packaged product. This is easily

achieved in cases where gaps can be left in the packaging material. The current trends on the

other hand have insisted on the implementation of continuous foam material. It is with this strict

limitation that high pressure water jet technology finds a suitable application. Water jet

technology is able to curve out a smooth outline of form that can be used for package modeling

in the packaging industry.

In order to accomplish a study of the effectiveness of the water jet technology on

modeling applications there is need to use a high pressure set up that has the capability of

supplying 400MPa and also achieving fluid flow rates of above 4 liters per minute. With a keen

study of the nozzle diameters, the depth of cut in foam can be studied in comparison with other

hard material applications. There are factors that play a vital role in the achievement of best cuts

and molds in foam when using high pressure water jet technology. Among the factors we have

the water jet pressure, orifice diameter, polymer concentration and the density of the foam that

should be cut.

In this application, the concentration of polymer material used for abrasive purposes

largely influences the depth of the cut that results. Using regression analysis the effectiveness of

high pressure abrasive assisted water jet can be studied. The equation below shows a general

model that an experiment can adopt.

Taking D as the depth of cut measured in cm.

P is the pressure of the water jet in MPa

V represents the traverse speed in cm/sec

k,y,z are coefficients of regression.


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The results found when water jet technologies are used in the process of cutting foam

indicate that the cut is deeper in soft materials when compared to hard materials. It is therefore

important that the users of the system know the density of the foam before setting the machine

into operation. The polymer effect on the depth of cut also indicates that deeper cuts are realized

when the concentration of the polymer increases. This approach has a limit of concentration

because the viscosity of the water is also affected. It is reported that polymer concentrations

beyond 0.5% result in very viscous water that results in ineffective operation.

A major advantage that comes with the use of the water jet technology, is the reduced

quantity of specific energy whenever faster speeds of operation and good quality cuts are

achieved. Studies also report that the water jet technologies report a reduction in specific energy

when the diameter of the nozzle is increased. This inherent characteristic of the water jet

technology facilitates its use in varied applications. This also places the high pressure water jet

technology in a special place in the list of technological advancement.

USE OF HIGH PRESSURE WATER JET DEVICES IN RECLAIMING MISSILES

CASINGS.

The application of high pressure water based technologies in operations that involve

explosives and ammunitions has risen in the past decade. This increase results from the

numerous advantages that result from this use. This side of high pressure water jet application

finds basis in the conventional cleaning application that largely affect inert materials as opposed

to the dangerous military oriented applications. In order to achieve this, objectives laid down by

the teams that were designing this phase of water jet technology included establishing the

effectiveness of the approach in completely getting rid of the explosive material remains.

Another objective was to establish if the pressures involved would not ignite the materials into


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exploding and increasing damage. Casing exist that facilitate this process. This casings ensure

that the explosive material is accessed in very small bits hence prevent the occurrence of

excessive pressure beyond values of 100MPa.

A suggestion for such an application recommends the use of a dual orifice

implementation. A dual orifice implementation carries with it the advantage of covering the

whole surface occupied by the explosive as the case is rotating. A second advantage is that the

setup is able to accomplish wider areas of coverage without the need for an additional supporting

mechanism. Being that an average of 1.5cm of the explosive would be cleared by a single sweep

of the orifice; the water jet technology nozzle has proved to be the best option in these

applications.

It is important that those engaging in the activities of removing explosives remains

consider a suitable depth of material removal. The reason behind this is that some explosive

types are fitted into the cans that carry them by use of billets. Keeping the thickness of material

removal to less than 100mm would ensure that only small fragments of the explosive material

chip off. The advantage of this approach is that the orifice opening is shielded from the blocking

effects that could result if larger thicknesses were used. The danger of larger thicknesses is its

capability to block the lance passage or even interfere greatly with the direction of the jet flow. A

remedy to a blockage case is to apply a reverse rotation to the lance drum. This enables the stuck

particles to fall out of the space between the lance and the casing. An advanced alteration of this

setup enables the realization of a multi directional cleaning equipment. An example of such an

implementation is the WOMBAT. WOMBAT stands for the Waterjet Ordinance and Munition

Blastcleaner with automated Tellurometry. This device has the capability to negotiate numerous

small diameter turns in order to accomplish cleaning in the blast cylinders.


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In the use of the water jet technology in cleaning munitions there is a great need to

address the issue of reaction and subsequent explosion. These are vital matters because they are

related to security. In testing the setup for ammunition cleaning, the amount of pressure at which

the cleaning process becomes unsafe is very important. The measure of the impact pressure that

would ignite a subsequent explosion can be achieved by the use of cavitation techniques on thin

films of explosives. A foundational database of information that guides the impact sensitivity

levels has been generated and documented. The database is a result of simulated experiments

that optimal conditions to the explosive particles with the aim of establishing the safe operating

zones. For instance, acoustic drivers have been used in generating 20KHz vibrations which are

used in the experiment of ascertaining the pressure that ignites explosive particles. The induced

frequency of vibration sends the water into a state of oscillation hence cavitation is induced into

the water. The process of cavitation consequently drives bubbles down to where the explosive

surface is situated. The continuous flow of the bubbles on the surface of the explosive material

causes an erosive effect. Though observations indicate a possibility of reaction, the levels of

bubble and explosive material reaction are very low. The results further indicate that the use of

waterjet impact in removing explosives requires a minimum of 1 million psi pressure in order to

set the process of reaction into motion. This basis has prohibited the use o cavitation in the

process of removing reactive material from the surface of munition cylinders.

PAVEMENT CUTTING

Pavements around the world get renovated quite frequently. This process of renovation

involves cutting the pavement open and then embarking on the tasks of maintenance accordingly.

This process involves meeting electric cables and also gas piping and other communication

conduits that are laid beneath the pavement. These processes of renovation have been facilitated


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using mechanical applications and methods. The reason for development of water jet solutions

for this task is to utilize the advantages that come along. Studies indicate that water jet pavement

cutting is able to achieve depths of 9 inches per minute when used on asphalt layers covering

layers of concrete. The cost involved in the water based solutions is minimum when compared to

other pavement cutting methods like the use of diamond and pneumatic breakers. The users are

able to benefit further if the renovators target to reuse the blocks after the work of renovation is

done. This is due to the fact that water jet technology does not break up the block when opening

up the pavement. The systems under development indicate a further reduction in costs of

operation because the system will be able to implement both circular and linear cutting and also

recycle the water used during the cutting process.

The main motivating factors towards the use of waer jet technology in renovating

pavements are the efficiency and safety that comes intact with the technology. The gas industry

is keen to have the gas fittings safely buried in the ground. With the renovation processes

involving the removal of pavement and excavation of the soil, it is evident that the pipes of gas

are not shielded from the effect of the processes. Both the removal and the return of the

pavement blocks poses a considerable chance at tampering with the gas pipes. This calls for a

safe, fast and cost effective method of implementing renovation processes. Looking at the

intensity of labor displayed by the conventional methods, it is desirable to implement the water

jet technology in handling renovations. For instance diamond saws, impacting breakers, jack

hammers and massive cutting wheels are expensive together with an immense energy

requirement. These methods also suffer from the problem of adjusting to the different scenarios

of pavements. Another inherent property of these cutting techniques involves the low quality of

cutting that largely hinders the speed of replacement of the pavement. The numerous


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disadvantages of the conventional methods have pushed for the water jet system that will

alleviate the massive costs incurred in line with gas distribution system installation, maintenance

and monitoring.

This application largely uses the cavitation technique that fails in the explosive removal

setup. The idea behind the cavitation process in pavement renovation involves the induction of

explosive vapour that fills the cavities in the pavement to be cut. The continued presence of the

vapor increases the pressure in the pavement block thereby eroding the pavement. The cavitating

fluid jet has an advantage in this scenario over the conventional pump pressure and fluid flow

rates. Initial studies indicated that a plain water jet at a pressure of 70MPa could easily cut

through a pavement on the street. This was achieved at the flow rate of 20gpm under hydraulic

power ratings of 83kW. This was able to cut a pavement at the depth of 8 inches per minute. It

takes 1 minute to be able to achieve a 1.5 by 3 inch block cutting from the continuous pavement.

These results do not include almost five minutes that are used in fracturing the concrete block

and another five minutes in removing the material that has accumulated in the hole. This

translates into 23 minutes. When compared to the conventional pneumatic jack hammer we

realize that the water jet method is faster by almost 20 minutes. This is part of the factors that

have motivated the growth of the water jet technology tailored towards pavement renovation and

maintenance. The water jet technology targets the following objectives related to pavement

renovation and maintenance. The water jet technology targets, an economical solution for cutting

pavement. It also targets to introduce a solution that is self contained and easily portable. With

this characteristic the system will easily be deployed and set up without a great need of

manpower. The system using water is able to capture both the residue of the cutting process and

the excess flowing water. With such a facility, the water jet system is in a position to recycle


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water used so that the resource is largely conserved. The water jet system also targets the ability

to cut a precisely measured block that may be returned at its original position. This objective is

tailored towards the effective use of concrete thereby preventing any cases of wastage. One more

important objective relates to the safety gained by the system. The water jet technology seeks to

implement a solution that is both safe to operate and easy to maintain. In order to achieve this,

the development team targeted a simple and very reliable system.

A model of the system exists with the following features: a circular pavement cutter. This

unit is designed in order to facilitate ease in deploying and positioning the cutting part. The

pavement cutter unit also enables the trapping of a big percentage of the residue that arises out of

the cutting process. The pavement cutting unit has the capability of implementing up to 4ft

lengths of block. Fashioned with wheels, the circular pavement cutter has motion capabilities

that enable its deployment to numerous points on the streets. This is facilitated by the ability to

lift the blade when the machine is not in active operation. The storage point of the residue is held

tight using a rubber band. The reason for the rubber band is to prevent the cover from coming off

due to the intensive vibrations that the system experiences.

Water in this equipment enters at high pressure levels. The pressure levels involved in

operating the machine can reach magnitudes of 10,000 psi. This waster is delivered by a 20mm

hose which is tied tightly to the swivel connector that ensures that the hose negotiates turns of

several degrees. Another feature that comes along with the cutter unit is the adjustable nozzle. In

order to facilitate the large diameter of pavement cuts, the nozzle is adjusted so that it can

facilitate larger cutting diameters. The sump pump works to separate the water already used and

the debris that comes off the pavement. The circular pavement cutter unit uses the sump pump to

push the used water through the filtering system so that the water can be recycled.


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The water pumping unit is a vital component of the circular and linear pavement cutting

unit. With this pump it is possible to raise high working power of about 110kW. With this power

there exists the possibility of raising as much pressure as 70MPa at a flow rate of 20gpm. This

system is flexible enough to use two pumps incase a higher rate of flow is desired.

Another vital component of the pavement cutter is the hydraulic Power and the unit for

control. These units are separate from the pressure unit because of the need to dedicate enough

power into driving the motors that rotate the cutting unit and rotating the pump that controls the

collection of the debris and the used water.

The implementation of the pavement cutter solution also has a four step fine tuned

filtering unit. These units are implemented in series so that the system is able to produce clean

water that can be used again in the cutter system. Experiments report that almost eight hours of

continuous water use can be achieved by the system. These results are evident without cases of

pressure drops in the working system.

Results obtained from implementing the equipment in the field indicate that the

equipment offers a great chance of manipulating and altering the flow rate. With this capability,

it is possible for the system to achieve faster rates of cutting. When applied to many types of

concrete, the flow rate forms a considerable factor in setting the optimum parameters for the

efficient implementation of the pavement cutting process.

Another achievement that surfaced from the application of the pavement cutting system is

the capability to take up the soil chipping that arises after the concrete block has completely been

milled. Advanced study into filter design suggests that newer systems should include filters that

are able to work with soil particle and concrete block debris.


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The objective of developing a safe system has been achieved. This comes to reality

because the system is able to collect all the readings and controls and display them on a control

screen. The merit that accompanies this is that the system can be operated comfortably by a

single operator. The system can be deployed by a retractable system that facilitates the maximum

utility of street space.

Statistics indicate that the water jet system is preferable because it tends to address the

current prevailing conditions in the field. This system has been championed to be good at

payback period. This arises from the low operating costs after the considerably high value of

acquisistion.

It is envisioned that the circular pavement cutter will find use in applications that require

underground entry. Such applications include, telephone maintenance that needs the workers to

gain entry into the junction and then use tools to access the conduits underground. The linear

cutter on the other hand will facilitate longer lengths of cutting. These involves repair works that

are tailored towards excavating a whole section of a tunnel and then replacing the portion. This

application requires more access space when compared to the circular cut areas. The modes of

powering the units have been hydraulic. More areas of exploration include the use of pneumatic

power in implementing the pressure levels.

WATER JET TECHNOLOGY AND DEMOLITION EXERCISES.

The United States of America has found a massive area of applying hydro technology in

demolishing weak and substandard bridges. The reason why all bridges should be maintained at

optimum working conditions is that the transport sector forms a large percent of the ecnomy

movers. For instance, the United States of America derives more than 22% of its GDP from the

transport and related sectors. These areas need an efficient and effectiveness program that is keen


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on the prevalent economic times. This basis calls for a cost effective system. The hydro based

solution offers the combination of the factors. Studies also indicate that hydro based solutions

have surpassed human power by a ratio of 7. These results are based on the power of the jack

hammer. The results of such implementations indicate that the state is able to save a lot of

money and time is it targets to implement hydro based technology for the demolition of

substandard bridges and other parts of the transport infrastructure. The rate of deterioration

shown by the bridges in the United States is alarming. This has posed a great danger to both the

users of the transport system and the authorities charged with the responsibility of renovating

them. the authorities in charge of renovating these bridges find it expensive with time to execute

the break down and renovation of the bridges. The need for keeping costs in manageable margins

leads the United States to seek for affordable options that would not hurt the economy a great

deal. This case is real because the nation has allocated a slim budget for the sake of bridge pull

down and renovation. The areas that experience high levels of traffic are in need of quicker

renovation services when compared to the areas that experience less traffic. The water jet system

finds the best answers for these needs.

The rate of bridge deterioration has increased in the past years because of the change in

the anticipated factors that affect bridge deterioration. These factors have accelerated the pace at

which bridges have become less useful and hardy. The projected span of service of a bridge is

usually 85 years averagely. Due to the increase in the motor industry since the late 1940s, roads

and bridges have supported traffic levels that exceed the initial envisioned capacity. Another

major factor that has accelerated the pace at which most bridges have lost strength and traffic

support is the placement of the reinforcing bars way close to the surface. The final factor that has


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influenced the quick deterioration of bridges is the increase in the attacks of chlorides. This

arises from the increased chloride levels in the atmosphere due to higher chemical use.

Statistics indicate that the number of motor vehicles has increased by about fifteen times

in the last half a decade. If this numbers are to go by, then the United States has experienced

more than 180 million new vehicles as compared to the previous statistics of about 1million new

cars per year. Additional statistics report that more heavy commercial trucks have been

manufactured and run on our roads at the moment. This adds on the stress that the old model

bridges are forced to bear.

The interstate program necessitated the placement of shallow support bars. Consider the

condition that stipulated that bars were supposed to be 1.5 inches below the ground. With the

current state of affairs, this standard is fairly shallow leading to an urgent need of renovating the

currently existing bridges so that they may conform to the current rates of traffic and the weight

trends. The state of the bridges is made worse by the poor work done by the contractors then

because of inadequate civil techniques and supervisory techniques. The air spaces that were left

in the roads to facilitate the process of aeration and road expansion have been negatively affected

by the chloride particles and other chemicals. These particles penetrate and clog the spaces while

others completely corrode the concrete and join the air spaces. This has the resultant effect of

causing cracks in the pavement due to the successive processes of expansion and contraction.

The problem is made worse when the cracks enlarge and allow the entry of more chlorides hence

increased corrosion and crack formation.

Studies take a keen interest in the bridges that constructors made between 1900 and 1980.

With the estimated rate of deterioration it is evident that the bridges require urgent repairs in

order for them to continue serving the economy without anticipated health and safety issues. This


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calls for preventive and maintenance tailored approaches. With the cost of effecting these

renovations in mind it is vital that effective an efficient maintenance procedures be implemented

on the bridges.

The conventional methods of maintenance were not very effective because they were

largely inaccurate. The lead maintenance engineer used he jack hammer to establish areas that

had holes on the bridge. This involved the dragging of a chain on the bridge while studying the

kind of sound that would originate. If the sound indicated a hollow section the engineer would

mark it out for purposes of repair. The areas that the engineer had marked out would be

excavated by a team of 7 to 10 men. These men used sledge hammers to break apart the marked

area so that a filling process could be implemented. The undoing of this process is that the

removal process is rather slow and used massive levels of energy. Another undoing of this

method was related to the accuracy of the method. The method is slightly inaccurate because of

the high dependence on the engineers efforts at locating the points of weakness. If the engineer

left out a region that required urgent repairs then the process of repairs may not achieve the

desired results. This is due to the repair session that would follow not long after the current repair

session.

The jet stream technology has come in handy in handling tasks that are related to bridge

renovation and repair. This technology makes use of two vital components. The demolition robot

and the demolition pack. These components are dependent to the extent that they have to work

together all the time.

DEMOLITION ROBOT

The demolition robot has the nozzle that executes the cutting. This can be fixed or

flexible so as to facilitate rotational cutting. The robot has the capability of changing the traverse


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speed together with the speeds of progress in the forward direction. The robot has been touted to

cut up to widths of 12 feet. And deliver maximum pressure levels of about 30,000 PSI. This

pressure levels require a massive amount of water to the tune of 85 gallons per minute. An

advantage that accompanies the design of the robot is that the robot has noise and dust control

mechanisms. This minimizes the effect of the cutting robot on the environment. The robot has

the capability of running the whole time under the close supervision and control of a single

technical operator. The robot also boasts of the capability to run on asingle or dual power pack.

When the robot is running on a single power pack it can accomplish light cutting tasks. When it

is running on dual power pack, the robot is able to accomplish increased pressures and water

flows hence faster cutting and productivity.

THE POWER PACK

This is a mobile unit has the dimensions of about 8 foot by 8 foot by 20 foot. It has

electric cables and high pressure water hoses that are connected to the robot. The power pack has

noise filtering hence can run without causing unnecessary disturbance in the environment. The

power pack can be located as far as 265 feet away from the centre of robot action. This enables

the work to occupy as little continuous space as possible. With this strategy, the renovators of the

pavement are able to avoid the unnecessary closure of streets because of the need for space.

OPERATION PRINCIPLE

The robot uses the following mode of operation. The robot delivers massive water jets at

high pressure into the capillaries in the concrete and air ducts. This executes the part of removing

the delaminate and weathered pieces of concrete. When the water is fully occupying the

available space in the concrete, it is forced tof low back to the entry point hence causing a state

of tension in the concrete. This tension enables the removal of the concrete block covering the


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point that needs renovation. With this format in place, there is no need to use blasting as a

method of renovation hence a lot of benefit because concrete blocks are reused.

This technology has been actively used since mid 1980s. This was applied in New York

by the New York state Thruway authority. Having been used on demolition of a bridge, the

method was very desirable. The method was able to accomplish the entire work of renovation in

four months. This was almost ten months before the budgeted time. This was inspite of the extra

amount of work that was introduced by new concrete blocks that were worn out. Another reason

that facilitated this speedy work was the capability to hook a extra power pack that facilitated

higher pressure values. The robot also enabled the workers on site to run a 24 hour operation as

opposed to the shorter hours executed by men alone.

A comparison between the efficiency of men working with a jackhammer and the hydro

technology indicates that it takes longer for the jack hammer to implement a small amount of

work. For instance, it took a seven man team manning a jack hammer 2 weeks to excavate a total

to 3600 square feet. The hydro technology being manned by a single operator was able to

accomplish more than twice the work accomplished by the jackhammer. The disadvantage that

comes with the use of the jackhammer is that there are unnecessary costs that come along. For

example, the jack hammer is not precise in relation to the depths of drilling. The jackhammer

also suffers the effect of grinding the adjacent blocks of concrete. This means that the renovators

expend more concrete bars in the covering exercise. This increases the cost and the time invested

in such renovation exercises. It is with this basis that the hydro technology is given preference

against the jackhammer implementation.

Hydro technology forms a massive force in renovation exercise as the nature of buildings

and architecture continues to advance. A specific mention comes for the multi story parking lots


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that need a careful demolition approach. The hydro demolition delivers a quieter and cean

solution for the renovation industry. The technology is also fast and thereby able to stretch the

taxpayers money for a longer duration of structure service.

HYDROTECHNOLOGY AND NUCLEAR FACILITIES

The field of nuclear testing comes with the effect of nuclear radiation spills and also

contamination. With this state of affairs there is need for the facilities that have accomplished

their mandate to be decommissioned and decontaminated. This process involves the organized

disposal of the nuclear facility taking a keen interest in the anticipated effect on the environment

and the safety that will result. The process may demand that the whole facility is pulled down

though numerous decontamination efforts involve the selective removal of areas that are

contaminated. If the building is not brought down, the decontamination efforts enable the owners

of the building to release the building out for other purposes. The abrasive water jet forms a good

approach in the target for safe and contamination free environments. This follows from the

requirement that large chunks of concrete are removed from the wall and the pillars so that the

deposits are accessed easily and washed out. In order to accomplish this duty, the abrasive

assisted water jet technology uses the kerf tool. The kerf tool is able to tear through thick

concrete walls and pillars so that the authorities can achieve decommissioning of the facility. The

kerf tool has a rotating nozzle that makes the initial slot of about 25mm in the wall. The tool

gains entry through this point and cuts through the concrete.

An inherent advantage that comes with this system is the ability to execute computer

control. The computer system ensures that the nozzle is headed in the correct direction and

navigates it through rebars and other hard aggregate sections.


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The system also has a cleaner or a scarifier. This is the tool that enables the system to

initiate and complete the decontamination process. The scarifier identifies layers of concrete that

are contaminated with deposits of nuclear material and sprays the surface with jets of water so as

to decontaminate them. this system is also able to clean metal surfaces from the heavy deposits

of nuclear materials. For example concrete can be cleaned of the nuclear materials at the rate of

11 square meters per hour when the depth of penetration is 7mm.

The use of the hydro technology enables the decontaminators to reduce on the amount of

contaminated debris. This is achieved through the initial isolation of the contaminated blocks

from the rest of the building that can be demolished using conventional means. There are times

that warrant remote access because of the levels of radiation involved. In such cases robots under

computer control can be used so that safety levels are maintained. The hydro system comes with

the capability of holding the spoils that are contaminated so that they can be collected for proper

disposal exercises.

Numerous sites have been identified as contaminated zones in the United States. This

statistics hold water because of the increase in nuclear activity in different sectors of the

economy. Among the areas that hold massive deposits we have reactor buildings, fuel processing

plants, burial grounds and trenches together with laboratories used for nuclear testing.

The size of walls involved in such exercises reaches a maximum of about 1.5 meters in

thickness. The hydro system gains popularity because of the faster speeds of action it displays

when compared to the conventional methods that are slow in action. There are requirements and

procedures that must be fulfilled in the quest for a safe and effective decontamination exercise.

These include: total capture of all the debris with contamination. This ensures that there is no

release of the nuclear contamination to the public. This requirement also facilitates the blockage


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towards recontamination that may occur during cutting of the concrete block. Another

requirement is that the process should be in a position to prevent additional waste during the

process of removing the contaminated concrete.

The process should achieve a state of removing only the concrete layer that is affected by

the nuclear deposits while leaving the uncontaminated surfaces unscathed. With this requirement

in place it is vital to note that the bars of concrete and reinforcement should experience uniform

cutting without the need to change any part of the nozzle or pressure chambers. Another

requirement for smooth operations involves the ability to adapt the machine for deployment to

centers outside the vicinity of developed towns in order to do the decontamination activities.

During the process of operation it is recommended that the system remains as silent as it can be.

This prevents the effect of contamination spread that comes as a result of vibrating the concrete

structures. The vibrations may also lead to excessive noise and eventual collapse of the building

if it is not very strong. The system should be easy to repair together with ease of operation that

entails the use of protective gear so that the users are not affected by the radiation. The process

of raising abrasive water jets involves the mixing of high velocity water with particles that

enables the mixture to perform very high cutting rates. This mixture is able to act hard on very

tough materials that are present in the concrete blocks.

The Kerf tool

This tool consists of numerous parts that act together thereby facilitate the deep cutting

process required for the decontamination to happen. Among the most important parts we have

the nozzle stem, the swivel, the shroud and catcher together with system responsible for

disposing of the collected remnants of the decontamination process.

The Nozzle stem


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A deep nozzle stem is desirable in all cases because of the nature of applications

involved. This design is given preference over other models because it is easily fabricated and

applied in the field. The nozzle that gives a single jet is preferred because it cancels out the effect

of complexity and enhances the uniformity that is required in the depth of the concrete under

decontamination.

The high pressure swivel

This part of the deep Kerf tool enables the feeding of the abrasives into the mixing

chamber. This part is vital because it is used for generation of speeds that are necessary for the

effective generation of high pressure. A study of the swivel indicates that the abrasives gain enty

into the mixing chamber at an angle. The reason for this is that angular entry reduces the

impedance effect that a perpendicular entry would have. If this were the case then the system

would become very inefficient. The lower part of the swivel has a bearing that facilitates rotation

between the outer casing of the swivel and the mixing chamber. The rotation facilitates

unblocking of the system incase particles get into the system.

Traverse mechanism and obstacle detector

This part is important for the purposes of three dimensional movements. The mechanism

has the capability of achieving about 1.5 meters of traverse motion coupled with about a half a

meter per minute traverse speeds. In order to achieve deeper stem and nozzle penetrations the

depth motion is increased. This complete mechanism works to facilitate the third angle of

rotational motion.

There is a great need for the system to block the used water and the debris from the

concrete from splashing back into the nozzle. This particular task is achieved by the shroud and

catcher. This system ensures that the area under cutting is completely sealed . for instance the


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catcher frame is fitted with a sealing rubber that runs along the block of concrete as the work

progresses.

The top and bottom end of the kerf has a vacuum controlled slot that uses the splashed

back water pressure to move the debris through system into the collection tank. The system is

very effective to magnitudes of about 95% of the total debris collected from the system.

The collection tank that keeps the spoils has three compartments. This tank separates the

debris from the water and air. The second compartment is controlled by a floating switch that is

able to turn the system off in case the water tank becomes full. The final compartment has a

collection point for the air which may have concentration of the poisonous gases. This progress

in the use of water jet technology indicates that there is a lot of room for extensive application of

this technology. It is also important to note that the nature of safety provided by the deep kerfing

technology is unparalleled in the nuclear field.

DEEP ROCK OIL MINING USING JET KERFING

High pressure water jet systems have found increased application in the oil mining and

deep rock cracking and penetration. Though initial efforts bore very limited fruit, the current

development of a dual conduit indicates that there is a lot of success that will come to mining

field through the High pressure water jet technology. The setup of the system has an annulus

kind of setup. The inner section carries the cutting fluid though in low volume but at high

pressure. The outer annulus carries low pressure but high volume debris that have been ejected

from the rock surface.

The system maintains its pressure by ensuring that the system is always under continuous

fluid flow. The pressure chamber maintains its pressures thereby enhances the pressure levels

that occur on the rock surface. Pressure levels of about 135MPa are realized by the system and


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this ensures effective rock cracking and consequently rock penetration. The system also makes

use of overbalance pressure. This pressure acts to hike the pressure threshold that is needed for

kerfing low permeable materials. This is similar to the process of confining stress in a rock

sample that is deeply dug. The overbalance of mud pressure works to increase the specific

energy that is required for the purposes of implementing the Kerf effect.

CONCLUSION

The rate at which high pressure water technologies are taking up complex applications is

amazing. It is with this rate of adoption that the field of science recommends that most areas of

the economy should pick up the technology and use it for effectiveness and efficiency. The water

jet technology boasts of very high safety guarantees. This comes because the system does not

have physical parts that may force physical contact. Systems that use the water jet technology

also benefit from the durability that comes because of limited heat generation.

The current rate of building deterioration also indicate that there is a great need for safe

and environment friendly technologies that will ensure the tax payer saves a great deal. The

water jet technology serves as a leading concept deliverer in the industry.


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REFERENCES

1. Bitter, J. G. A. A Study of Erosion Phenomena: Part I Wear, Vol 6 pgs. 7-21, 1963.2. Eisfeld, F., The investigation of the Penetration of Liquid Jets in Gas by the methods of

high speed cinematography and short time interferometry. Proceedings of the society of

PhotoOptical Instrumentation Engineers, Vol, Pt. 1, 1984, pp. 330 - 336

3. Hashish, M., A Modeling study of metal cutting with abrasive water jets, ASMETransactions, Journal of Engineering Materials and Technology. Vol. 106, pp. 88100,

1984.

4.

Mazurkiewicz, M., The Analysis of the possibility of Bunching with a High Pressure

water jet. Proc Second U. S. Water jet Conference, 1983, 8pp.

5. Nebeker, E. B., Rodriguez, S. E., Percussive Water Jets for Rapid Excavation, 1973,Scientific Associates, Inc

6. Preece, C., Editor, Treatise on materials science and Technology, Erosion, Vol. 16.Academic Press, New York, 1979.

7. Rouse, H., Cavitation in the Mixing zone of a submerged jet, La Houille Blanche, JanFeb. 1953, pp.9 -19.

High Pressure Water Jet Technology

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