WATER JET CONFERENCE - Waterjet Technology Association

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due to wear. Although actual operating costs are not available, reasonable operating costs can be estimated since the costs of each element are well known. 5.1 Estimated Hourly Costs The major operating cost is the cost of equipment. Based on a price of $100K, a 15-percent interest rate over a period of five years, and 10,000 hours of total operating time, the equipment cost is estimated at $15/hr. The cost of power is about $3/hr. The nozzle replacement cost is projected at $1/hr. Abrasive-jet cutting using throwaway abrasives, at a rate of 2 lb/nin, will cost $5/hr, at an average cost of 5//lb for abrasives. The overall hourly cost will then be $25/hr. Taking into account other running costs, such as pump parts, cleaning, water, orifice jewels, etc., a cost of $27/hr becomes a reasonable estimate. Figure 13 shows estimated hourly cost figures for some applications. 5.2 Comparison with Other Cutting Methods There are several techniques for cutting metals being used by the industry that could be replaced by abrasive-jet cutting under special circumstances. Figure 14 shows the cutting thickness range for metals by several methods along with the present, experimentally proven range for abrasive-jet cutting. These methods are oxyfuel torches, plasma torches, lasers, mechanical saws and diamond wires. The hourly operating costs for these methods are estimated to be as little as $2/hr for oxyfuel, mechanical saws and diamond wires. They increase to more than $20/hr for lasers and plasma torches. Based on these rough estimates, it can be said that abrasive-waterjet cutting is more expensive than plasma, lasers, oxyfuel torches, etc., in their respective optimal thickness ranges. However, mechanical saws can cut only in straight lines and the other methods induce thermal effects and, in many instances, produce a poor quality surface that must be machined. Abrasive-waterjet cutting presents a totally different method for cutting advanced materials and, thus, could be economical for a number of metal cutting applications. These include cutting of titanium, ceramics and graphite-epoxy composites that can also be cut, but with difficulty, by conventional means. For concrete cutting applications, the actual comparison of the cost of conventional concrete cutting systems with abrasive-waterjet cutting is difficult to make. It suffices to say that abrasive waterjet cutting provides smoother cuts, possibly faster cuts, minimum disturbances to adjacent structures, and is vibration free. These secondary benefits make abrasive-waterjet cutting the preferred method in a large number of applications. 5. ENVIRONMENTAL CONSIDERATIONS The environmental aspects of materials cutting discussed here are (1 ) those aspects related to the nature of the abrasive-waterjet cutting process and its related equipment and (2) comparisons with other competitive techniques. 6.1 Abrasive-Waterjet Cutting Process and Its Equipment In the abrasive-waterjet cutting process, the significant environmental concerns are: 423
- High pressures - Noise levels - Hazards due to rebounding abrasives - Pollution with abrasives Commercial equipment used in waterjet cutting applications, such as pumps providing high pressures up to 60 ksi, tubes, fittings, valves, swivels and other components, are well within the safety standards and codes of environmental organizations. High-pressure flexible hoses are available with a maximum safe operating pressure of 35 ksi. This is more than adequate for most abrasivewaterjet cutting applications. Both mechanical and aerodynamic noises are associated with abrasive-jet cutting. The mechanical noise is primarily that of a diesel or gasoline engine or an electric motor. The aerodynamic noise is from free jets traveling at higher velocities than the speed of sound. This occurs when large standoff distances are used or when material penetration by a jet results. While cutting at reasonable standoff distances, the abrasive jet is quieter than most mechanical tools, especially if material is thick or if the jet is caught as it exits the kerf. Under these conditions, hearing protection devices night not be necessary, but their use is always a good practice. The rebound of abrasives in the jet back flow, which results from cutting thick materials without penetration, nay be hazardous. However, this rebound can be prevented by shielding the nozzle with a shroud. To prevent pollution and to adhere to strict environmental regulations, the catching of abrasives and cleaning up after cutting is essential. The cutting process does not produce airborne particles that might be hazardous to the health of an operator who is properly protected. 6.2 Comparison with Other Techniques Most of the environmental benefits of abrasive waterjet cutting are realized in field applications. When abrasive jets are used in the field for cutting concrete, e.g., for underground utility access manholes or road and bridge repair, the noise and fatiguing characteristics of conventional tools, such as jackhammers and air operated drills, are eliminated. Because abrasive jets cut faster and require less manpower, traffic disturbances will be minimized. This is an important advantage, particularly in heavily populated areas. The remote operation capability of abrasive-jet systems will be a great advantage for operating in contaminated areas. Compared with cutting using flames, the use of abrasive jets eliminates the danger of explosives in potentially hazardous areas (Saunders, 1982). Abrasive waterjets also require minimal support of the work piece because they produce very little force and they do not heat up a workplace to any significant amount. 7. INDUSTRIAL APPLICATIONS AND BENEFITS OF ABRASIVE WATERJETS The potential applications of abrasive-jet cutting are numerous. Because of the technical and economic performance of abrasive waterjets, many industries could immediately benefit 424
Page 1 and 2:
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
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
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 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 452 and 453: pressure can be wiped out if diffic
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 &
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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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