WATER JET CONFERENCE - Waterjet Technology Association

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pressure can be wiped out if difficulties in abrasive entrainment start to appear because of reduced water flow rate. Opposite to the effect of water pressure, there may exist a "threshold hardness" in the selection of abrasives for cutting rock or other hard materials with Abrasion Jet. The effectiveness of Abrasion Jet in cutting a given material may show sudden improvement when a softer abrasive is replaced with one that is harder than the target material. The effectiveness of an abrasive may be related also to the fragility in impacting a given target material. The shape of abrasive grains in relationship to the structure of the target material could also be important. Thus, the "hardness" alone may not be adequate in describing the relationship between the abrasives and rock in Abrasion-Jet cutting Jet Exposure Time The data obtained in this work showed that the effect of nozzle traverse speed on the depth of Abrasion-Jet cutting of rock may follow a simple relationship, involving the length of time that rock was exposed to jet impingement, which may be called Exposure Time and may be estimated by: T = n d / v (1) where T = Abrasion Jet exposure time, second n = number of pass d = diameter of Abrasion Jet, inch v = speed of nozzle traverse, inch per second. Thus, multiple-traverse cutting data could be lumped together with single-pass cutting data obtained at various nozzle traverse speeds. When the depth of cut is plotted against the exposure time on logarithmic scale, straight lines can be expected. It is possible that a family of lines can be obtained for a given rock in that changes in the abrasive feed rate will change the slope of the lines while changes in water pressure produce a group of parallel lines. Rock of different types will have family of lines situated at different parts of this chart. In other words, the term of "jet interference" mentioned in high-pressure waterjet cutting of materials may not have any meaning in Abrasion-Jet cutting as the effect of abrasive particles grossly overshadowed that of the waterjets such that the cutting of rock is reduced basically to an abrasion process. In such process, the number of impacts made by the high-speed abrasive particles within a unit time basically determines the rate of material removal. The kinetic energy of the impacting abrasive particles and the characteristics of the impact are two finer points of this abrasion process. Nevertheless, the ability of waterjet in exploiting fractures created by the impact of abrasive particles cannot be ignored. The presence of the water stream also allows the abrasive particles to impact the rock more than once and prevents the particles from rebounding after impact. 445
SUMMARY AND CONCLUSIONS The data collected in this study showed that waterjets of moderate pressure can effectively cut very hard rock if suitable abrasives are entrained into the waterjet without sacrificing the quality of the waterjet. It also showed that Fluidyne's Abrasion-Jet nozzles can provide the desired abrasive entrainment without severe wear problems of nozzle parts. This study also showed that entrainment of abrasives into a group of waterjets is a complex process, involving the interactions of several factors. Good abrasive entrainment has been shown to be a prerequisite of generating high-performance abrasive waterjet. With the use of hard and sharp abrasives and an effective nozzle, water pressure was found to be of secondary importance in cutting hard rock . The process of Abrasion-Jet cutting of rock is believed to be basically an abrasion process in which the number of impacts made by the high-speed abrasive particles within unit time determines the cutting rate. This process can be optimized by considering the following aspects listed in the order of decreasing priority: • Entrainment of abrasives into waterjets • Characterization of abrasives in respect to properties of rock involved • Water flow rate and abrasive feed rate • Water pressure • Nozzle traverse speed • Nozzle standoff distance • Jet impingement angle. Further studies are required to understand the finer points involved in each of these aspects. ACKNOWLEDGMENT The author is indebted to the support provided by the National Science Foundation for this study. REFERENCES 1. Barton, R.E.P., and Saunders, D.H., 1982, Water/Abrasive Jet cutting of Concrete and Reinforced Concrete: 6th ISJCT Paper K4. 2. Easton, N., 1978, Wet Abrasive Blasting: U.S. Patent 4,125,969. 3. Fair, J.C., 1981, Development of High-Pressure Abrasive Drilling: J. Pet. Tech., August, p 1379-88. 4. Griffth, N.J., and Godding, R.G., 1980, A Preliminary Investigation Into Abrasive <strong>Waterjet</strong> Cutting of Cast Iron: BHRA Report RR-1629. 5. Hart, B.E., 1976, Guns for Forming Jets of Particulate Material: U.S. Patent 3,972,150. 6. Hashish, M., 1982, The Application of Abrasive Jets to Concrete Cutting: 6th ISJCT Paper K2. 7. Hashish, M., 1982, Steel Cutting With Abrasive <strong>Waterjet</strong>s: 6th ISJCT Paper K3. 8. Lamb, R.W., 1976, Abrasive or Sand Blasting Apparatus and Method: U.S. Patent 3,994,097. 446
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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
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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
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
Page 424 and 425: CUTTING WITH ABRASIVE WATERJETS M.
Page 426 and 427: 3.3 Abrasive Feed Systems For abras
Page 428 and 429: Because of the large number of infl
Page 430 and 431: due to wear. Although actual operat
Page 432 and 433: from this new technology. Table 2 l
Page 434 and 435: Table 1. materials cut by abrasive
Page 436 and 437: Figure 1. Abrasive waterjet nozzles
Page 438 and 439: a) kerfs in mild steel b) S.S. 15.5
Page 440 and 441: a) circle cutting in glass b) lamin
Page 442 and 443: DISCUSSION NAME: Andrew F. Conn COM
Page 444 and 445: CUTTING HARD ROCK WITH ABRASIVE-ENT
Page 446 and 447: slurry nozzle. Testing at water pre
Page 448 and 449: DISCUSSION OF TEST RESULTS Jet Conf
Page 450 and 451: materials. The flexibility in nozzl
Page 454 and 455: 9. Maurer, W.C., and Heilheckler, J
Page 456 and 457: Figure 5. Effect of abrasive feed r
Page 458 and 459: Figure 9. Accumulated depth of mult
Page 460 and 461: Figure 13. Close-up view of quartzi
Page 462 and 463: ABRASIVE INJECTION USAGE IN THE UNI
Page 464 and 465: sudden changes in the feed rate eff
Page 466 and 467: or the abrasive must be manually to
Page 468 and 469: clog; there not being sufficient ar
Page 470 and 471: CODE OF PRACTICE FOR THE USE OF ABR
Page 472 and 473: Figure 5. Water abrasive cleaning h
Page 474 and 475: Figure 15. 360 0 abrasive pipe clea
Page 476 and 477: ECONOMIC CONSIDERATIONS IN WATER JE
Page 478 and 479: Other criteria to be considered in
Page 480 and 481: 3 MANUAL METHODS OF JET CLEANING &
Page 482 and 483: contractor with old, unsafe, equipm
Page 484 and 485: Figure 1. Showing the increased cos
Page 486 and 487: Figure 8. Automatic tube bundle cle
Page 488 and 489: ackground to the subsequent coopera
Page 490 and 491: The molecules of SUPER-WATER posses
Page 492 and 493: shaken just before use. SUPERWATER
Page 494: 26. Bednarz, L.P., "Effects of Poly
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