WATER JET CONFERENCE - Waterjet Technology Association

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Various designs and applications are feasible, e.g., for cleaning work and for the destruction of connecting elements during salvage work in the face/ gate road intersection (Fig. 16). SUPPLY BOREHOLES A further task results from the need for coal gasification underground. In order to ensure the recovery of deposits in great depths which poses numerous problems to conventional mining, a concept of borehole sinking for the supply of gasification agents was developed. The high-pressure water is supplied via a steel tube fed from a tube reel via a guide unit to advance the nozzle ahead (Fig. 17). The borehole diameter is 80-100 mm, the desired borehole length some hundred meters. MINI-FULLFACER WITH HIGH-PRESSURE <strong>WATER</strong> <strong>JET</strong>S The so-called rock back-cutting principle was again adopted for mechanical roadway drivage. The tests carried out in the hard coal industry more than 20 years ago with the Wolmeyer roadheader have gained renewed importance as a result of the new application potential of high-pressure water jets (Fig. 18). In the context of a cooperation agreement with Messrs. Atlas-Copco Sweden, who made available, free of charge, a roadheader of the Mini-Fullfacer type, first preliminary tests have been started in the Herdecke quarry. As with profile cutting, the standard cutting pick is equipped with high-pressure nozzles to extend the application range of this roadheader to hard and abrasive rock (Fig. 19). In the meantime, a roadway length of 20 m has been drifted, initially without high-pressure water. In sandstone, the back-cutting depth is 100 mm and more with a cutter width of only 35 mm (Fig. 20). The wedge-shaped cutter pick breaks the back-cut rock rib. This results in a very favorable breaking performance/cutting work ratio. LICENSING PROCEDURE AND SAFETY AT WORK Both commercial use and testing of roadheaders as well as testing installations require the official approval in the Federal Republic of Germany. All underground cavities with a cross-section of more than 8 m 2 extracted without direct access from the surface are subject to Para. 130 of the Mining Law. Besides, the mutual indemnity association of the mining industry and the trade supervisory office are involved in the licensing procedure as official authorities. The risks associated with the use of high-pressure water jets essentially relate to the high pressure and the noise level. Water pressures are up to 4,000 bar, noise levels up to 97 dB(A) when cutting rock and 122 dB(A) for open jets. The essentially higher noise 349
level for open jets can largely be prevented during practical application of high-pressure water. To reduce any related effects, the following personal protective measures are made compulsory, apart from technical requirements for machinery (Fig. 21): - reinforced rubber boots - protective suit against splash water - protective gloves - helmet with eye protection - noise protection - respiratory protection (for use of additives). EVALUATION Summarizing the results and experience made so far with the novel heading systems, the potential advantages of a technical-economical and reasonable application in the hard coal industry may be evaluated as follows: The applicability of the techniques studied could basically be confirmed. As to conventional operation of cutting tools in particular, the high cutting force components required could substantially be reduced, or the rate of advance could alternatively be increased using the same thrust. Besides, there were both positive effects on tool wear and important economic advantages. The tests have also shown, however, that the energy requirement is relatively high. A reduction of the energy requirement could, for example, be achieved by selective application of the high-pressure water jets in particular areas, such as at the periphery and in the center of the roadway. High-pressure water jets combined with carbide picks have proved to be highly effective. In contrast, rock destruction by water jets alone has an extremely high specific energy requirement since the water jet, as an excellent means of cutting, is not suited to extract larger rock volumes. Further tests were conducted to improve the effect of high-pressure water jets by additives. The results have confirmed that, by using additives in the high-pressure water, the slot depth can be increased by up to 100% (Fig. 22), or that the pressure can be reduced by 30% for the same slot depth. Most of the above-mentioned development work of Bergbau-Forschung GmbH is still in the laboratory stage. Based on the results achieved, however, field tests on large technical scale could already be carried out which will, in one or another case, certainly lead to a further improvement of roadheading techniques. 350
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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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Page 308 and 309: Table 1. Concrete saw technology. T
Page 310 and 311: NAME: Tom Brunsing COMPANY: Foster-
Page 312 and 313: FEASIBILITY STUDY OF CUTTING SOME M
Page 314 and 315: hydraulic power required to cut thr
Page 316 and 317: pressure was varied from 103 to 310
Page 318 and 319: 2.1 Heading and gutting fresh cod f
Page 320 and 321: Figure 5. The cuts surface of a blo
Page 322 and 323: 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 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 374 and 375: Figure 5. 3 ft. diameter laboratory
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
Page 390 and 391: out thoroughly an efficient scheme
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
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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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