WATER JET CONFERENCE - Waterjet Technology Association

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For test purposes, these concrete blocks were transported and held in the bucket of a front end loader attached to a Kubota L245DT tractor. The blocks weighed about 500 pounds each. This arrangement gave a steady platform for testing, and the four-wheel drive feature of the tractor allowed the blocks to be easily moved through mud and water. RESULTS Based on the procedure discussed earlier for low pressure testing at 500 psig, the standoff distance at which the ordinary jet was no longer able to cut was 35 feet. The Percussive Jet's cutting ability deteriorated to the same level at a standoff distance of 55 feet. This represents an increase in cutting distance of 60% by this criteria. However, at intermediate distances, the difference in Percussive Jet and ordinary jet performance was more significant. An example is shown in Figure 8. In this test, the two jets were discharged side-by-side under identical conditions with the concrete test block placed 25 feet (600 nozzle diameters) from the nozzle. As shown, the Percussive Jet firings removed about twice as much material as the ordinary jet. Hence, all other conditions remaining the same, the Percussive Jet required about half the specific energy as the ordinary jet. Most interesting was the shape of the Percussive Jet craters. Each was about 2 1/2inches in diameter but had a deep central hole less than one-inch in diameter. In approximately one-half of the tests, these deep central holes wandered off in one direction or the other in the concrete blocks. The presence of these deep central holes gives further evidence of the presence of a "tight," relatively undisturbed central core of the Percussive Jet even at large standoff distances. The performance of the Percussive Jet was optimized when the 3/4-inch diameter bypass was used in the modulator to control the modulation amplitude. At these low pressures, an optimum in modulation frequency was not found. Performance increased monotonically as frequency increased to 400 hertz. During high pressure testing at 2,000 psig using procedures outlined earlier, the ordinary jet failed to cut the test blocks at about 60 feet (1440 diameters) from the nozzle, whereas the Percussive Jet could extend out to 75 - 80 feet (1900 diameters). This represents an improvement of about 30%. At closer distances to the nozzle, the results were again more apparent. Figure 9 shows an example of a concrete block that was impacted by a Percussive and ordinary Jet at 45 feet (1080 diameters) from the nozzle. As illustrated, the Percussive Jet removed about 15 times as much material as the ordinary jet. Hence, the specific energy requirements of the Percussive Jet are in the range of an order of magnitude less than an ordinary jet under these conditions. These high pressure tests illustrated the same type of crater as evidenced in low pressure testing: a crater with a deep central hole. In the example of Figure 9, the small central hole is 2 inches in diameter in the center of a larger crater 9 inches in diameter. 35
Hence, this high-pressure testing gave further evidence supporting the existence of a "tight" central core. The optimal performance of the Percussive Jet discharged at 2,000 psig was obtained using the same 3/4-inch diameter bypass used to produce the best low pressure cutting results. However, in contrast to the low pressure results, an optimal modulation frequency of about 230 hertz was found. The reason for the existence of a maximum in cutting performance with frequency is subject to speculation at this time. Most likely, this maximum has its origin in the fluid mechanics of the free jet rather than in the interaction of the Percussive Jet with the material. Several interesting observations were made upon examination of the test specimens after they had been impacted by the Percussive Jet. Such observations were made repeatedly. These are listed below and briefly discussed. None of these effects was ever observed while using an ordinary jet. Percussive Jet Craters. Large craters with deep central holes discussed earlier. Cracking In Concrete Blocks With Smooth Faces. Figure 10 shows an example of the impacted surface of a concrete block 60 feet away from the nozzle when hit by a Percussive Jet discharged at 2000 psig for 5 seconds. The surface of the block was originally smooth. Such a result also occurred during a demonstration before Department of Energy and Bureau of Mines personnel. These results cannot be explained in detail at this time but probably result from the complicated pattern of repetitive stress waves set up in the material by the Percussive Jet. Cracking In Concrete Blocks With Surface Imperfections. Results similar in appearance to Figure 10 were obtained when the Percussive Jet impacted within a few inches of a shallow surface groove or scratch in the concrete surface. Again, the detailed explanation is a complicated one but perhaps the Percussive stress wave pattern was "concentrated" near the crack. Stresses are known to increase like 1/ r as they approach the tip of a crack (where r is the distance from the stress wave to the tip of a crack) (Jasper and Cook, 1971). Large-Scale Breakout of Nonhomogeneous Surface Materials. In cases where the surface of the concrete had aggregate or other non-homogeneous substances cast in or near the surface, stress wave propagation dislodged large areas of the material. A typical example is shown in Nebeker (1983). Presumably, this type of result is due to the compression-tension mechanism discussed in Nebeker and Rodriguez (1973). ACKNOWLEDGEMENT This activity was performed on U. S. Department of Energy Contract DE-AC01- 79ET14280. Currently, the technical project officer is Mr. Robert J. Evans. Earlier, the technical project officers were Mr. Hamilton Reese, Jr. and Mr. Howard Parkinson assisted by Dr. Sedat Sami. 36
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 34 and 35: NAME: Gerald Zink COMPANY: StoneAge
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 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
Page 84 and 85: Figure 5. Wall velocity distributio
Page 86 and 87: Figure 9. Effect of nozzle design o
Page 88 and 89: Figure 12. CA+T Design Philosophy.
Page 90 and 91: Figure 16. Effect of inlet b 1 cond
Page 92 and 93:
Figure 20. Relaminarization at nozz
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Figure 24. Pressure decay data. 88
Page 96 and 97:
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
Page 268 and 269:
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
Page 368 and 369:
Results of Trial Tests As part of m
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cutting rates, degree of bit wear,
Page 372 and 373:
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
Page 494:
26. Bednarz, L.P., "Effects of Poly
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