WATER JET CONFERENCE - Waterjet Technology Association

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NAME: Gerald Zink COMPANY: StoneAge, Inc. DISCUSSION QUESTION: The power needed to vaporize half of the jet flow would seem rather high. When a continuous jet is caught and all its energy converted to heat, the water is a few tens of degrees warmer than the upstream temperature. To vaporize the water would take considerably more power. ANSWER: I checked my calculations once more, and I have no reservations. For evaporating 1 kg. of water in 100°C, we need 2260 10 3 Joules, which means that for evaporating a portion of water having 0.1 mm diameter and length of 0.1 mm, we need 1.775 x 10 3 Watts. This can be done in 0.001 sec. For example, the power consumption will then be 10775 Watts, for 0.0001 sec. evaporating time will be 0.1775 Watts. These results proved my calculations. It is the same range results. NAME: William Lindenmuth COMPANY: Tracer Hydronautics QUESTION: When calculating laser power, did you include efficiencies for: 1) creating the laser, and 2) laser/jet evaporation?" ANSWER Yes, I did. I took into consideration pretty high value of the dissipate ratio (X = 2). Possibly, further corrections can be made after further experiments. NAME: Eugene Nebeker COMPANY: Scientific Associates, Inc. QUESTION: Bear in mind that you are destroying an appreciable amount of energy and momentum when you interrupt the jet with the laser. Also the optimum shape of the front of your slug may not be flat. When you proceed into the experimental portion of your program, some insight may be obtained relative to these comments." ANSWER: This is true. I do destroy a portion of energy and momentum by cutting out a segment of jet; but also, I clearly developed single segments of jet, which do much more effective work than solid jets. Besides, my expectation is, that concave heads of jet segments can be created and additional gain can be achieved by Monroe jets: The experimental trials are absolutely necessary for an evaluation of a proposed method. 27
STANDOFF DISTANCE IMPROVEMENT USING PERCUSSIVE <strong>JET</strong>S Eugene B. Nebeker, Ph.D. Scientific Associates, Inc. Santa Monica, California ABSTRACT A fundamental modification of the fluid mechanics of an ordinary, continuous water jet was shown to increase the standoff distance or cutting range. This paper indicates how this was accomplished by using the Percussive Jet. Examples of the results are presented. In static firings, the maximum distance from the nozzle the Percussive Jet could cut cement block targets was 30 to 60 percent greater than an ordinary jet. At distances closer to the nozzle, the Percussive Jet often did 15 to 20 times the damage to the target material than the ordinary jet. These results will be useful to the Department of Energy high-volume and borehole hydraulic mining systems as well as to the other jet systems where cutting range is important. Percussive Jets apply force to rock as a sequence of high-frequency impacts, rather than steadily. These Jets can be produced with a conventional, continuous flow system by modulating the discharge, i.e., cycling the discharge rate by a small amount above and below its average. With modulated discharge, the faster part of each cycle overtakes the slower in the free stream. If this process is done properly, the stream becomes bunched instead of uniform, and a Percussive Jet is produced. The fluid mechanism by which the Percussive Jet can increase standoff is briefly discussed. Reliable and simple hardware was produced which could effectively create and control these Jets. A variety of interesting test specimen failures resulting from Percussive Jet loading were observed. INTRODUCTION Hydraulic coal mining has been used in various parts of the world for many years, having been used in the Soviet Union, for example, since 1935. More recently, Kaiser Resources, Ltd., Canada, has operated a most successful hydraulic mine in British Columbia and has planned to design others. The reasons for the increasing popularity of hydraulic coal mining include less capital and operating cost per unit of coal cutting capacity and production, greater safety and reduced health hazards for operators, increased equipment simplicity and reliability, etc. Realizing these aspects of hydraulic mining, the Bureau of Mines and Department of Energy have sought to develop two basic types of large-diameter hydraulic mining systems: high-volume and borehole systems. The role of the Percussive Jet is similar in each system. The Percussive Jet technique will be used to improve the range of the jets or to improve ease by which the coal is cut at any distance from the nozzle. In practice, the conventional nozzle will be removed from these systems and replaced by a Percussive Jet 28
Page 1 and 2: Proceedings of the Second U.S. WATE
Page 3 and 4: Visualization of the Central Core o
Page 5 and 6: A Status Report on the Conceptual D
Page 7 and 8: SESSION 7 - CIVIL & INDUSTRIAL Chai
Page 9 and 10: Cutting Hard Rock With Abrasive-Ent
Page 11 and 12: frictional and piping component rel
Page 13 and 14: R = a1 ⋅ A1 A2 a2 I = 2H o Q o
Page 15 and 16: attenuation of the output. The tran
Page 17 and 18: Figure 1. Branch System Modulator F
Page 19 and 20: Figure 5. Modulation Response for B
Page 21 and 22: Figure 9. Modulation response for s
Page 23 and 24: can be used for any form of input.
Page 25 and 26: with a cylindrical shape to the jet
Page 27 and 28: m/s. The range of power found from
Page 29 and 30: Figure 3. Power vs nozzle diameter
Page 31 and 32: Figure 5. Frequency vs length of th
Page 36 and 37: modulatornozzle assembly. The ordin
Page 38 and 39: DISCUSSION OF FLUID MECHANICS The i
Page 40 and 41: This process serves to protect the
Page 42 and 43: For test purposes, these concrete b
Page 44 and 45: REFERENCES CITED 1. Barker, C. R.,
Page 46 and 47: FIGURE 4. INNER CORE OF PERCUSSIVE
Page 48 and 49: FIGURE 9. EXAMPLE OF HIGH-PRESSURE
Page 50 and 51: NAME: John E. Wolgamott COMPANY: St
Page 52 and 53: THE FOCUSED SHOCK TECHNlQUE FORPROD
Page 54 and 55: The reflected wave is thus also cyl
Page 56 and 57: neglected. The introduction of a co
Page 58 and 59: DISCUSSION NAME: George Savanick CO
Page 60 and 61: H’ mean shape factor Hj theoretic
Page 62 and 63: Required streamline curvature at th
Page 64 and 65: 2 x 2 ≅ ( e − 2 p + w)/k2 (2-8)
Page 66 and 67: eliminating 2 n r 2 from equations
Page 68 and 69: approximation to the actual flow si
Page 70 and 71: skin friction coefficient but are c
Page 72 and 73: where: (H) = A1H 3 + A2H 2 + A3H +
Page 74 and 75: effect (< 0.5%) on coefficients of
Page 76 and 77: TABLE 5 Rei x 10 5 β 3 4 5 6 Po Po
Page 78 and 79: TABLE 6 D(mm) d o(mm) L t(mm) L f(m
Page 80 and 81: expanding rather than contracting a
Page 82 and 83: 25. Weber, H.E., 1978, Boundary lay
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Figure 5. Wall velocity distributio
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Figure 9. Effect of nozzle design o
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Figure 12. CA+T Design Philosophy.
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Figure 16. Effect of inlet b 1 cond
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Figure 20. Relaminarization at nozz
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Figure 24. Pressure decay data. 88
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VISUALIZATION OF THE CENTRAL CORE O
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DISCUSSION Although employing the i
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5. Lambert, J. H., 1760, Photometri
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Figure 6. Spectral sensitivity curv
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NAME: W.C. Cooley COMPANY: Terraspa
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INTRODUCTION Pulsed liquid jets sho
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y=X ∨ P A dy = p p A p 2 (L c y=0
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Using equation (15), the value of X
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Thus about the first 10% of the dri
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Many design cases, including those
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surface spall occurred, resulting i
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Figure 3. Chamber pressure at pisto
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Figure 7. Effect of nozzle area rat
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Figure 11. Extrusion device schemat
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Figure 15. Typical chamber pressure
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DISCUSSION NAME: W. C. Cooley COMPA
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material which are, in turn, affect
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the water jet. This method was not
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where h is the depth of penetration
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obtained during this phase of the i
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observed that the smallest depth of
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Figure 2. Idealized Relationships b
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Figure 6. Penetration as a Function
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DEVELOPMENT OF VARIABLE DELIVERY TR
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THE STRUCTURE AND FUNCTION OF THE P
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The injection pressure can be contr
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ACKNOWLEDGEMENTS The authors gratef
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Figure 4. Theoretical required powe
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Figure 9. Variation of efficiency w
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THE "SKIPJACK" SEWER CLEANING NOZZL
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HYDRO-BLASTING SAFETY C.W. Adaway,
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Remember, your Hydro-Blasting work
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horizontal, sometimes vertical, and
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Figure 2. Safety Gear Figure 3. Tub
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DEVELOPMENTS IN CLEANING COKE OVEN
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causing chain breakages and the scr
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was encountered, then the rotation
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(C) Capital Expenditure: Material i
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Figure 9. Swivel coupling Figure 10
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OPTIMIZING JET CUTTING POWER FOR TU
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PRESSURE DROP (psi) ELEMENT Cv @10
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power output. Undersized nozzles re
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Subscripts n - Nozzle p - Pump t -
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Figure 1. Cutting effect as a funct
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CONSIDERATIONS IN THE COMPARISON OF
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pressure can be lowered to perhaps
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Figure 2: Fan jet issuing from a no
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DISCUSSION NAME: John Griffiths COM
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where Q = Flow rate - gpm D = Jet O
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Again, not limited to Newtonian flu
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REFERENCES 1. Brown, R.W. and Loper
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Table 2. Jet Cleaning Speeds and ot
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ANSWER: The utilization of the stat
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complexity and short component life
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Figure 4, for ap values ranging fro
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Decontamination Methods for rapidly
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a. “PULSER” b.”ORGAN-PIPE”
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Figure 5 - Removal rate for various
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DISCUSSION NAME: David A. Summers C
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DRILLING BORE HOLES IN COAL MINES U
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pile could not be judged as represe
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DISCUSSION NAME: David Summers COMP
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HYDRAULIC MINING EXPERIMENTS IN AN
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The monitor was fed pressurized wat
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The IH rig was considered to be sup
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REFERENCES 1. Okhrimenki, V. A., A.
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Figure 2. Jet cutting sandstone at
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Figure 5. Schematic plan view of In
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Figure 7. Suction Box. 226
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USE OF HIGH PRESSURE WATER JETS FOR
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flame torch to cut this block, redu
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the order of 360 rpm. Under these c
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Figure 3. Slot cut by jet at 11 o s
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JET-MINER SURFACE AND IN-SEAM TRIAL
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The hydraulic drive of the haulage
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The surface trials had have the obj
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Figure 2. Experimental version. Fig
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Figure. 7 Jet-Miner prototype Figur
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SOME PATTERNS OF TECHNOLOGY TRANSFE
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Development of High Pressure_Techno
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configurations, the design of an op
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and public sectors. After a haitus
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Souder, W.E. and Evans, R.J., "The
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Figure 5. Technological achievement
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Table 3. Perceived disadvantages of
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already been, or is being applied w
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Using the requirements profile and
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ant hose combination, a guiding sys
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HYDRAULIC MINING TESTS Site selecti
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SAFETY All operations were carried
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TABLE V. Categories of Jet Mining D
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Figure 2. Generalized geologic prof
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SECONDARY FRAGMENTATION WITH WATER
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do possess a maximum point (Fig. 8)
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Figure 4. Rossin-Rammler plot. Figu
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Figure 8. Non-dimensional plot for
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HYDRAULIC COAL MINING SYSTEM Typica
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Figure 4. (From ref. 1) DISCUSSION
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INTRODUCTION Developing an unique t
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The coefficients "b " in Eq. (1) ca
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By the end of 1982, a total of more
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Figure 4. Cutting ability of swing-
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Figure 10. An operating performance
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for an abrasive, the abrasive parti
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the particles, while at slower spee
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to break away the remaining segment
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Table 1. Concrete saw technology. T
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NAME: Tom Brunsing COMPANY: Foster-
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FEASIBILITY STUDY OF CUTTING SOME M
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hydraulic power required to cut thr
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pressure was varied from 103 to 310
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2.1 Heading and gutting fresh cod f
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Figure 5. The cuts surface of a blo
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Figure 17. Cuts made across the cla
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JET NOTCHING USED IN THE CONSTRUCTI
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Bottom notch diameter was determine
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σ H = in-situ stress in the horizo
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Figure 3. Final block displacement.
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Figure 8. Comparison of Slurry Pump
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THE FURTHER DEVELOPMENT OF AN UNDER
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use taps or hydrants. To achieve th
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supply line. It was determined that
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The rotating head requires major mo
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Figure 4. System field test set-up
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Figure 10. Bentonite drilled clay s
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MECHANICAL TOOLS Cutting Tool Energ
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Ψ = cos −1 ⎧ ⎪ ⎪ ⎨ ⎪
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mode also contributes to chip flush
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NAME: Simon Johnson COMPANY: Newcas
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ROLLER TOOLS COMBINED WITH HIGH-PRE
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Various designs and applications ar
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Figure 1. Full-face tunneling machi
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Figure 11. roadway profile cutting
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Figure 19. High-pressure water jet
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DESIGN AND OPERATION OF TWO LARGE-S
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The hydraulic system for the thrust
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Results of Trial Tests As part of m
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cutting rates, degree of bit wear,
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Overall approximate Weight: Basic M
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Figure 5. 3 ft. diameter laboratory
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nozzle diameter and cutting speed w
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2. Cutting Speed The influence of c
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energy it effects an increase in me
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Tip angle (degrees) 87 Off-set angl
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Figure 5. Figure 6. Figure 7 Figure
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Figure 17. Figure 18. Figure 19. Fi
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SCHEMES OF COAL MASSIF BREAKAGE BY
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out thoroughly an efficient scheme
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Research analysis has proved that t
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DEPENDENCE OF POWER INDICES OF COMB
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The experiments have shown how the
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K Ay = coefficient correcting for f
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Figure 1. Schemes of combined break
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Figure 5. Dependence of specific en
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Figure 12. Percentage of grade R -6
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Figure 1. Particle size analysis. T
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NAME: Dr. Henkel COMPANY: Bergbau-F
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presented. This study, of course, i
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identifying a general trend for the
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Effect of Abrasive Hardness, Shape
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In some situations, especially in c
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Figure 1. Abrasive waterjet nozzles
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Figure 8. Effect of standoff distan
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Figure 13. Abrasive waterjet cuts i
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CUTTING WITH ABRASIVE WATERJETS M.
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3.3 Abrasive Feed Systems For abras
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Because of the large number of infl
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due to wear. Although actual operat
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from this new technology. Table 2 l
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Table 1. materials cut by abrasive
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Figure 1. Abrasive waterjet nozzles
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a) kerfs in mild steel b) S.S. 15.5
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a) circle cutting in glass b) lamin
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DISCUSSION NAME: Andrew F. Conn COM
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CUTTING HARD ROCK WITH ABRASIVE-ENT
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slurry nozzle. Testing at water pre
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DISCUSSION OF TEST RESULTS Jet Conf
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materials. The flexibility in nozzl
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pressure can be wiped out if diffic
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9. Maurer, W.C., and Heilheckler, J
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Figure 5. Effect of abrasive feed r
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Figure 9. Accumulated depth of mult
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Figure 13. Close-up view of quartzi
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ABRASIVE INJECTION USAGE IN THE UNI
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sudden changes in the feed rate eff
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or the abrasive must be manually to
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clog; there not being sufficient ar
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CODE OF PRACTICE FOR THE USE OF ABR
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Figure 5. Water abrasive cleaning h
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Figure 15. 360 0 abrasive pipe clea
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ECONOMIC CONSIDERATIONS IN WATER JE
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Other criteria to be considered in
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3 MANUAL METHODS OF JET CLEANING &
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contractor with old, unsafe, equipm
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Figure 1. Showing the increased cos
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Figure 8. Automatic tube bundle cle
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ackground to the subsequent coopera
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The molecules of SUPER-WATER posses
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shaken just before use. SUPERWATER
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26. Bednarz, L.P., "Effects of Poly
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