WATER JET CONFERENCE - Waterjet Technology Association

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The injection pressure can be controlled easily by changing the prescribed pressure in the hydraulic cushion cylinder with the relief valve in the hydraulic circuit. CHARACTERISTICS OF THE PUMP Characteristics of Power In this section, the effect of power reduction of the hydraulic cushion cylinder is analyzed by means of calculation of torque characteristics. Figure 3 shows the structure of the crank. Provided that the force on the piston acted by the pressure in the hydraulic cushion cylinder is F and that on the crank shaft F1, Torque T is: where = sin −1 (− R sin ) L F1 = F cos ( − ) T=F1 R sin(θ - φ)=F R sin cos The displacement of the plunger is: 140 (12) (13) X = R[(1+ cos ) − r (1 − cos2 )] (14) 4L Figures 4 - 7 show the rotation force on the crank shaft worked by each piston and the resultant power K at four different delivery rates: O %, 50 %, 75 %, 100 % (plunger stroke:0,S/2, 3S/4 , S ). It is clear from these figures that the theoretical power acted by the hydraulic cushion cylinder decreases in proportion to the delivery rate; at the delivery rates of 0, 50 %, 75 %, the theoretical power corresponds at 0, 0.5, 0.75 . The triple reciprocating plunger pump with a pressure control discharge valve in the high pressure water circuit has the same power characteristics as in Figure 7. However, if the delivery volume decreases, the valve prevents the power reduction of Figure 4 -6 and maintains the total delivery power. Figure 8 shows the actual power consumed by the pump drive motor (actual power) and the retentive power of the total delivery from the nozzle (theoretical power), at a delivery pressure of 392MPa and variable delivery volume. The actual power also decreases in an approximate proportion to the delivery decrease. Figure 9 shows efficiencies in four different cases: 1) at full operation of the hydraulic cushion cylinder, 2) actual efficiency of the present pump, 3) efficiency of the triple plunger pump installed with a pressure control valve in the high pressure water circuit, and 4) efficiency of a hydraulic booster pump using a variable delivery hydraulic pump (max. efficiency 90 %). From these figures, the following results are obtained: In the existing triple plunger pump, the efficiency is reduced to 43 % by the same rate of decrease of delivery volume, while in the present pump it decreases to only 79 %. Further, it is always higher than that of the hydraulic drive booster pump at any delivery
volume. These results lead us to a conclusion that the present pump yields the highest flexibility and efficiency. Analysis of the Pressure variation Characteristics In any pump of the same crank structure as the present pump, the plunger speed varies with the change of revolution angle of the crank shaft, which induces a change in the discharge capacity and subsequent pulsation in the high pressure water circuit. Figure 10 indicates theoretical characteristics of the discharge capacity at maximum delivery. According to this figure, the pressure variation α1 is 20 %, which is equal to that of the existing triple plunger pump. At a delivery volume of less than 80 %, the sliding piston in the hydraulic cushion cylinder acts on each plunger to discharge a necessary volume constantly, so that the total compound discharge offsets pressure variation theoretically. Figure 11 shows the actual pressure variations in the high pressure water circuit at 100 % and 50 % of delivery capacity with 392 MPa of operational pressure. While the anti-pulsation effect of the hydraulic cushion cylinder is relatively small in this test (α 2=12 % at 50 %delivery), the pulsation has been reduced considerably compared to the existing hydraulic drive booster pump; for the total absence of pulsation, the required accumulator volume of the present pump is only 70 % of that of a hydraulic drive booster pump (reciprocation rate: 20/min) of the same power. DISCUSSION Subsequent to the development of a variable delivery plunger, the analysis of its characteristics confirmed a considerable effect of power reduction of the hydraulic cushion cylinder. However, the present test shows a gradual decrease of efficiency with the decrease of delivery volume (Figure 9). If the hydraulic cushion cylinder functions perfectly, the efficiency must be 86 % at any delivery rate. Possible reasons for this deterioration of efficiency are friction resistance of the packing caused by sliding of the piston in the hydraulic cushion cylinder and fluid resistance in the cylinder due to the discharge and inflow of oil. For the same reasons, the pulsation did not reach O at the delivery rate of 50 %. In Figure 5 (delivery volume at 50 %), our assumption provided that the pressing force of the piston at the time of oil discharge of the hydraulic cushion cylinder (F'’) equals to that at the time of oil inflow (F"); -F' = F". However, with a modified formula of -F' = 1.1 F", the average compound power of each piston becomes about -0.52, and the efficiency rate thereof −0.48 ⋅86 = 80 equals to that in Figure 9. −0.52 The following conclusions have been obtained from various tests carried out on the present pump. i) The power consumption can be controlled in proportion to the delivery volume to offer an efficient cutting operation. ii) The injection pressure control is easier than the existing triple plunger pump. iii) The pulsation is smaller than the existing hydraulic booster pump. 141
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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
Page 96 and 97: VISUALIZATION OF THE CENTRAL CORE O
Page 98 and 99: DISCUSSION Although employing the i
Page 100 and 101: 5. Lambert, J. H., 1760, Photometri
Page 102 and 103: Figure 6. Spectral sensitivity curv
Page 104 and 105: NAME: W.C. Cooley COMPANY: Terraspa
Page 106 and 107: INTRODUCTION Pulsed liquid jets sho
Page 108 and 109: y=X ∨ P A dy = p p A p 2 (L c y=0
Page 110 and 111: Using equation (15), the value of X
Page 112 and 113: Thus about the first 10% of the dri
Page 114 and 115: Many design cases, including those
Page 116 and 117: surface spall occurred, resulting i
Page 118 and 119: Figure 3. Chamber pressure at pisto
Page 120 and 121: Figure 7. Effect of nozzle area rat
Page 122 and 123: Figure 11. Extrusion device schemat
Page 124 and 125: Figure 15. Typical chamber pressure
Page 126 and 127: DISCUSSION NAME: W. C. Cooley COMPA
Page 128 and 129: material which are, in turn, affect
Page 130 and 131: the water jet. This method was not
Page 132 and 133: where h is the depth of penetration
Page 134 and 135: obtained during this phase of the i
Page 136 and 137: observed that the smallest depth of
Page 138 and 139: Figure 2. Idealized Relationships b
Page 140 and 141: Figure 6. Penetration as a Function
Page 142 and 143: DEVELOPMENT OF VARIABLE DELIVERY TR
Page 144 and 145: THE STRUCTURE AND FUNCTION OF THE P
Page 148 and 149: ACKNOWLEDGEMENTS The authors gratef
Page 150 and 151: Figure 4. Theoretical required powe
Page 152 and 153: Figure 9. Variation of efficiency w
Page 154 and 155: THE "SKIPJACK" SEWER CLEANING NOZZL
Page 156 and 157: HYDRO-BLASTING SAFETY C.W. Adaway,
Page 158 and 159: Remember, your Hydro-Blasting work
Page 160 and 161: horizontal, sometimes vertical, and
Page 162 and 163: Figure 2. Safety Gear Figure 3. Tub
Page 164 and 165: DEVELOPMENTS IN CLEANING COKE OVEN
Page 166 and 167: causing chain breakages and the scr
Page 168 and 169: was encountered, then the rotation
Page 170 and 171: (C) Capital Expenditure: Material i
Page 172 and 173: Figure 9. Swivel coupling Figure 10
Page 174 and 175: OPTIMIZING JET CUTTING POWER FOR TU
Page 176 and 177: PRESSURE DROP (psi) ELEMENT Cv @10
Page 178 and 179: power output. Undersized nozzles re
Page 180 and 181: Subscripts n - Nozzle p - Pump t -
Page 182 and 183: Figure 1. Cutting effect as a funct
Page 184 and 185: CONSIDERATIONS IN THE COMPARISON OF
Page 186 and 187: pressure can be lowered to perhaps
Page 188 and 189: Figure 2: Fan jet issuing from a no
Page 190 and 191: DISCUSSION NAME: John Griffiths COM
Page 192 and 193: where Q = Flow rate - gpm D = Jet O
Page 194 and 195: 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
Page 448 and 449:
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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