WATER JET CONFERENCE - Waterjet Technology Association

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The experiments have shown how the main indices of the combined breakage depend upon the depth of the disc cutter thrust (Fig. 13 and 14), and the rational values of this depth to produce but the minimum coal fines 0-6 mm have been determined: h = 6.8 - t/h (11) as well as that to produce the maximum of +25 mm coal lumps: h = 9.6 - 1.9 t/h. (12) CONCLUSIONS I. There are some schemes of the combined breakage of a coal massif by a high velocity water jet and a disc cutter developed and studied. Their characteristics have been determined, the main being as follows: (a) When introducing the disc cutter in the slot for a thrust depth which is smaller than the slot depth, a deeper slot leads to no change in the power parameters of the process and in the energy consumption for the mechanical breakage because the inter-slot pillar is broken but not for its entire height; (b) When introducing the disc cutter in the slot for a thrust depth which is more than the slot depth, the inter-slot pillar is broken practically along its base. And a deeper slot provides for a reduced resistance of the pillar to breakage and a smaller contact area of the disc cutter with the coal massif, thus reducing the disc cutter forces and the specific energy consumption for the mechanical breakage, and all of them reach their minimum at h s = (0.7+0.8) h; and (c) Application of a floating attachment of the disc cutter of a front type makes it possible to avoid the side thrust acting on its axis, and to reduce the cutting and forward forces, and to considerably lower the energy consumption for the breakage. 2. The most efficient scheme of the combined breakage of a coal massif providing for a minimum specific energy consumption for the mechanical and hydraulic breakage and the best coal grade is the scheme when the water jet cuts a slot to form an inter-slot pillar and to shear it towards the recently-exposed side surface with the one-sided wedge rim disc cutter while the thrust depth is more than the depth of the slot cut. 3. The efficiency of a water jet applied together with a disc cutter to break a coal massif depends upon their mutual disposition. Rational is the minimum distance between the axis of the disc cutter and the contact point of the water jet with the massif as far as the power parameters and specific energy consumption are concerned. 4. Besides the depth of the slot and the distance between the water jet and the disc cutter, the parameters of the combined breakage depend also upon the cutting pitch and thrust depth of the disc cutter, its geometric shapes and the coal strength properties. 389
5. It is established that for the hydromechanical method of breakage the use of the disc cutter with one-sided wedge rim instead of cutting instruments provides for a reduction in specific energy consumption for the mechanical breakage by 1.5-2 times. 6. When the disc cutter is used together with a high velocity water jet to break a coal massif, then, as compared to the mechanical method of breakage with a disc cutter, the forces acting onto the disc cutter are reduced: the rolling force by 1 5-2 times, the forward force by 1.2-1.4 times and the side thrust by 2.7-4.4 times and the specific energy consumption by 1.9-2.2 times. Besides, the coal grade is improved and dust content in the air is reduced to the permissible concentrations. The efficiency of dust suppression is 99.7-99.8 per cent for the hydromechanical method of breakage. NOMENCLATURE h = depth of thrust of disc cutter (web width), cm t = slot cutting pitch, cm h s = depth of slot cut by water jet in coal massif, cm a = distance between disc cutter axis and water jet contact point with coal massif, mm D = outside diameter of disc cutter wedge rim, mm δ = sharpening angle of disc cutter wedge rim, degrees HW = mechanical breakage specific energy consumption, XJ/m Eh = hydraulic breakage specific energy consumption, I';J/m) Eo = total specific energy consumption for hydromechanical breakage, RJ/m3 Uc = speed of cutting (speed of water jet and disc cutter movement), m/s nozzle diameter, mm Pz = cutting (rolling) force acting onto disc cutter axis during coal massif breakage, kN Py = forward force acting onto disc cutter axis during coal massif breakage, kN Px = side thrust acting onto disc cutter axis during coal massif breakage,kN = percentage of coal grade 0-6 mm R-6 R +25 = percentage of coal grade +25 mm Q = specific dust formation, g/t K = criterion for coal massif resistance to combined breakage = coal strength coefficient according to Prof.Protodyakonov scale = coal resistance to uniaxial compression, MPa = coal resistance to uniaxial tension, MPa Ry = coal resistance to cutting, N/cm =conventional compression strength of coal, MPa K Ryz = coefficient correcting for force P (energy consumption Hw)depending K Ryy = coefficient correcting for force Pv depending on Ry K Az = coefficient correcting for force P (energy consumption Hw) depending A 390
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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
Page 346 and 347: MECHANICAL TOOLS Cutting Tool Energ
Page 348 and 349: Ψ = cos −1 ⎧ ⎪ ⎪ ⎨ ⎪
Page 350 and 351: mode also contributes to chip flush
Page 352 and 353: NAME: Simon Johnson COMPANY: Newcas
Page 354 and 355: ROLLER TOOLS COMBINED WITH HIGH-PRE
Page 356 and 357: Various designs and applications ar
Page 358 and 359: Figure 1. Full-face tunneling machi
Page 360 and 361: Figure 11. roadway profile cutting
Page 362 and 363: Figure 19. High-pressure water jet
Page 364 and 365: DESIGN AND OPERATION OF TWO LARGE-S
Page 366 and 367: The hydraulic system for the thrust
Page 368 and 369: Results of Trial Tests As part of m
Page 370 and 371: cutting rates, degree of bit wear,
Page 372 and 373: Overall approximate Weight: Basic M
Page 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 398 and 399: K Ay = coefficient correcting for f
Page 400 and 401: Figure 1. Schemes of combined break
Page 402 and 403: Figure 5. Dependence of specific en
Page 404 and 405: Figure 12. Percentage of grade R -6
Page 406 and 407: Figure 1. Particle size analysis. T
Page 408 and 409: NAME: Dr. Henkel COMPANY: Bergbau-F
Page 410 and 411: presented. This study, of course, i
Page 412 and 413: identifying a general trend for the
Page 414 and 415: Effect of Abrasive Hardness, Shape
Page 416 and 417: In some situations, especially in c
Page 418 and 419: Figure 1. Abrasive waterjet nozzles
Page 420 and 421: Figure 8. Effect of standoff distan
Page 422 and 423: Figure 13. Abrasive waterjet cuts i
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
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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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