WATER JET CONFERENCE - Waterjet Technology Association

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Figure 5. 3 ft. diameter laboratory drilling fixture. Figure 6. Roadheader cuttinghead installed on the laboratory drill rig. NAME: Dr. Henkel COMPANY: Bergbau-Forshung DISCUSSION QUESTION: "Have you got already results from the optimum position of the nozzle in order to reduce dust, and/or to increase the cutting performance?" ANSWER: We believe the optimum nozzle positioning for a water jet assisted disc cutting system is behind the cutter with jet oriented to impinge the cutter path. The jet helps remove the crushed zone remaining in the cutter path to permit higher penetration for the successive cutter passes. An added benefit is the reduced cutter wear. Our results to date indicate that this beneficial effect of water jet assist can be obtained at pressures below 5,000 psi. 367
HYBRID ROCK CUTTING : FUNDAMENTAL INVESTIGATIONS AND PRACTICAL APPLICATIONS Orhan Tecen, Mining Division, Etibank, Turkey Robert J. Fowell, Lecturer, University of Newcastle upon Tyne, U.K. ABSTRACT Early experiments with water jet assisted drag tool cutting have shown that this mode of cutting has considerable promise in extending the strength and abrasivity range of rock materials that can be economically excavated by drag tools. The paper will describe some recent tests undertaken at the Department of Geotechnical Engineering in the University of Newcastle upon Tyne, England, where an extensive programme of fundamental studies on this aspect of mechanical excavation is currently being undertaken. Despite the promise of the early experiments the fundamentals of rock failure under the combined attack of both jet and drag tool have yet to be fully understood. This paper concentrates on the influence of cutting speed, jet pressure, and nozzle diameter on cutting efficiency and tool forces. The practical implications of the results obtained indicate that it is not always the highest jet pressures that provide the best results. INTRODUCTION Assisting the cutting action of drag tools by preceding their use with high pressure water jets has shown great promise in increasing the range of rock materials than can be excavated economically by roadheader tunnelling machines (Plumpton and Tomlin,1982). To investigate further the mechanisms of rock failure under this hybrid excavation system, initial studies were undertaken in the University of Newcastle upon Tyne in two sandstones with differing rock properties. The advantages of water jet assisted rock cutting appear to be: • Reduction in cutting forces acting on the tool and reduced torque fluctuations on the head. • Cooling for the tungsten carbide tipped cutting tool extending its economical life. • Cool the rock in the track behind the tool eliminating hot spots that could cause ignitions. • Suppress dust at source • Provide lubrication at the tool/rock interface. • Assist with debris removal. This paper reports the results for a limited range of tests which formed the first investigation undertaken for a much wider study of the issues involved. Jet pressure, 368
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Proceedings of the Second U.S. WATE
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Visualization of the Central Core o
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A Status Report on the Conceptual D
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SESSION 7 - CIVIL & INDUSTRIAL Chai
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Cutting Hard Rock With Abrasive-Ent
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frictional and piping component rel
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R = a1 ⋅ A1 A2 a2 I = 2H o Q o
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attenuation of the output. The tran
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Figure 1. Branch System Modulator F
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Figure 5. Modulation Response for B
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Figure 9. Modulation response for s
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can be used for any form of input.
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with a cylindrical shape to the jet
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m/s. The range of power found from
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Figure 3. Power vs nozzle diameter
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Figure 5. Frequency vs length of th
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NAME: Gerald Zink COMPANY: StoneAge
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modulatornozzle assembly. The ordin
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DISCUSSION OF FLUID MECHANICS The i
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This process serves to protect the
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For test purposes, these concrete b
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REFERENCES CITED 1. Barker, C. R.,
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FIGURE 4. INNER CORE OF PERCUSSIVE
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FIGURE 9. EXAMPLE OF HIGH-PRESSURE
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NAME: John E. Wolgamott COMPANY: St
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THE FOCUSED SHOCK TECHNlQUE FORPROD
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The reflected wave is thus also cyl
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neglected. The introduction of a co
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DISCUSSION NAME: George Savanick CO
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H’ mean shape factor Hj theoretic
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Required streamline curvature at th
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2 x 2 ≅ ( e − 2 p + w)/k2 (2-8)
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eliminating 2 n r 2 from equations
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approximation to the actual flow si
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skin friction coefficient but are c
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where: (H) = A1H 3 + A2H 2 + A3H +
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effect (< 0.5%) on coefficients of
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TABLE 5 Rei x 10 5 β 3 4 5 6 Po Po
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TABLE 6 D(mm) d o(mm) L t(mm) L f(m
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expanding rather than contracting a
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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
Page 324 and 325: JET NOTCHING USED IN THE CONSTRUCTI
Page 326 and 327: Bottom notch diameter was determine
Page 328 and 329: σ H = in-situ stress in the horizo
Page 330 and 331: Figure 3. Final block displacement.
Page 332 and 333: Figure 8. Comparison of Slurry Pump
Page 334 and 335: THE FURTHER DEVELOPMENT OF AN UNDER
Page 336 and 337: use taps or hydrants. To achieve th
Page 338 and 339: supply line. It was determined that
Page 340 and 341: The rotating head requires major mo
Page 342 and 343: Figure 4. System field test set-up
Page 344 and 345: Figure 10. Bentonite drilled clay s
Page 346 and 347: MECHANICAL TOOLS Cutting Tool Energ
Page 348 and 349: Ψ = cos −1 ⎧ ⎪ ⎪ ⎨ ⎪
Page 350 and 351: mode also contributes to chip flush
Page 352 and 353: NAME: Simon Johnson COMPANY: Newcas
Page 354 and 355: ROLLER TOOLS COMBINED WITH HIGH-PRE
Page 356 and 357: Various designs and applications ar
Page 358 and 359: Figure 1. Full-face tunneling machi
Page 360 and 361: Figure 11. roadway profile cutting
Page 362 and 363: Figure 19. High-pressure water jet
Page 364 and 365: DESIGN AND OPERATION OF TWO LARGE-S
Page 366 and 367: The hydraulic system for the thrust
Page 368 and 369: Results of Trial Tests As part of m
Page 370 and 371: cutting rates, degree of bit wear,
Page 372 and 373: Overall approximate Weight: Basic M
Page 376 and 377: nozzle diameter and cutting speed w
Page 378 and 379: 2. Cutting Speed The influence of c
Page 380 and 381: energy it effects an increase in me
Page 382 and 383: Tip angle (degrees) 87 Off-set angl
Page 384 and 385: Figure 5. Figure 6. Figure 7 Figure
Page 386 and 387: Figure 17. Figure 18. Figure 19. Fi
Page 388 and 389: SCHEMES OF COAL MASSIF BREAKAGE BY
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Page 392 and 393: Research analysis has proved that t
Page 394 and 395: DEPENDENCE OF POWER INDICES OF COMB
Page 396 and 397: The experiments have shown how the
Page 398 and 399: K Ay = coefficient correcting for f
Page 400 and 401: Figure 1. Schemes of combined break
Page 402 and 403: Figure 5. Dependence of specific en
Page 404 and 405: Figure 12. Percentage of grade R -6
Page 406 and 407: Figure 1. Particle size analysis. T
Page 408 and 409: NAME: Dr. Henkel COMPANY: Bergbau-F
Page 410 and 411: presented. This study, of course, i
Page 412 and 413: identifying a general trend for the
Page 414 and 415: Effect of Abrasive Hardness, Shape
Page 416 and 417: In some situations, especially in c
Page 418 and 419: Figure 1. Abrasive waterjet nozzles
Page 420 and 421: Figure 8. Effect of standoff distan
Page 422 and 423: 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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