EP0062111A2 — Enhancing liquid jet erosion

Claim 1

Independent Claim 55 words

A method of eroding a solid surface with a high velocity liquid jet, comprising the steps of: a) forming a high velocity liquid jet; b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2; and c) impinging the pulsed jet against the solid surface.

Claim 2

Independent Claim 55 words

A method of eroding a solid surface with a high velocity liquid jet, comprising the steps of: a) forming a high velocity liquid jet; b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2; and c) impinging the pulsed jet against the solid surface.

Claim 3

Dependent Claim 21 words

A method as claimed in claim 1, wherein the liquid jet is pulsed by mechanically oscillating the velocity of the jet.

Claim 4

Dependent Claim 18 words

A method as claimed in claim 1, wherein the liquid jet is pulsed by hydrodynamic and acoustic interactions.

Claim 5

Dependent Claim 39 words

A method as claimed in claim 1, wherein the liquid jet is formed by directing a liquid through an orifice, and the jet is pulsed by oscillating the pressure of the liquid prior to. directing it through the orifice.

Claim 6

Dependent Claim 32 words

A method as claimed in claim 4, wherein the pressure of the liquid is oscillated by directing the liquid through a hydroacoustic organ-pipe oscillator having a nozzle, said nozzle comprising said orifice.

Claim 7

Dependent Claim 54 words

A method as claimed in claim 1, wherein the liquid is directed through a first orifice and the jet is formed by directing the liquid through a second orifice, and wherein the jet is pulsed by oscillating the pressure / of the liquid after it exits the first orifice through hydrodynamic and acoustic interactions.

Claim 8

Dependent Claim 31 words

A method as claimed in claim 6 wherein a Helmholtz chamber is formed betwen the first and second orifices wherein the pressure of the liquid is oscillated within the Helmholtz oscillator.

Claim 9

Dependent Claim 25 words

A method as claimed in claim 3, wherein a portion of the energy of the high velocity liquid is utilized to pulse the liquid .

Claim 10

Dependent Claim 32 words

A method as claimed in claim 1, wherein the pulsed, high velocity liquid jet is surrounded by a gas and forms into discrete, spaced apart slugs, thereby producing an intermittent percussive effect.

Claim 11

Dependent Claim 17 words

A method as claimed in claim 9, wherein the liquid comprises water and the gas comprises air.

Claim 12

Dependent Claim 31 words

A method as claimed in claim 9, wherein the veloci-' ty of the jet is oscillated at a Strouhal number within the range of from about 0 .66 to about 0.85.

Claim 13

Dependent Claim 59 words

A method as claimed in claim 9, wherein the distance between the solid surface and the orifice from which the jet exits is determined by the following equation: where X is the distance, D is the orifice diameter, S is the Strouhal number, V is the mean jet velocity and v' is the oscillation amplitude about the mean velocity.

Claim 14

Dependent Claim 48 words

A method as claimed in claim 1, wherein at least a portion of the surface is fragmented into chips and wherein the pulsed liquid jet is surrounded by a liquid and forms into discrete, spaced apart vortices which spread over the surface, thereby enhancing removal of said chips.

Claim 15

Dependent Claim 61 words

A method as claimed in claim 1, wherein the pulsed high velocity liquid jet is surrounded by a liquid and forms into discrete, spaced apart vortices, and wherein vapor cavities of the liquid are formed in the vortices and the vortices spread over the solid surface at a distance from the orifice where said vapor cavities collapse, thereby producing cavitation erosion.

Claim 16

Dependent Claim 21 words

A method as claimed in claim 14, wherein the velocity of the pulsed liquid jet is at least about Mach 0.1.

Claim 17

Dependent Claim 29 words

A method as claimed in claim 15, wherein the velocity of the jet is oscillated at a Strouhal number within the range of from about 0.3 to about 0.45.

Claim 18

Dependent Claim 28 words

A method as claimed-in claim 15, wherein the velocity of the jet is oscillated at a Strouhal number within the range of from about 0.6 to about 0.9.

Claim 19

Dependent Claim 41 words

A method as claimed in claim 14, wherein the distance between the solid surface and the orifice from which the jet exits is no greater than about 6 times the diameter of the jet for cavitation numbers greater than about 0.2.

Claim 20

Dependent Claim 82 words

A method as claimed in claim 1, wherein the pulsed, high velocity liquid jet forms into discrete, spaced aprt vortices, and wherein vapor cavities of the liquid are formed in the vortices and the vortices spread over the solid surface at a distance from the orifice where said vapor cavities collapse, thereby producing cavitation erosion, the formation of vapor cavities being assisted by a center body located in the outlet of the jet-forming nozzle to form an annular orifice for the nozzle.

Claim 21

Dependent Claim 27 words

A method as claimed in claim 5, wherein the velocity of the jet-is oscillated at a Strouhal number within the range of from about 0.25 to 0.65.

Claim 22

Dependent Claim 45 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) means for forming a high velocity liquid jet; and b) means for oscillating the velocity of the jet at a Strouhal number-within the range of from about 0.2 to about 1.2.

Claim 23

Dependent Claim 45 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) means for forming a high velocity liquid jet; and b) means for oscillating the velocity of the jet at a Strouhal number-within the range of from about 0.2 to about 1.2.

Claim 24

Dependent Claim 20 words

Apparatus as claimed in claim 21, wherein the means for oscillating the velocity of the jet comprises a mechanical oscillator.

Claim 25

Dependent Claim 19 words

Apparatus as claimed in claim 22, wherein the mechanical oscillator comprises an oscillating piston or an oscillating mechanical valve.

Claim 26

Dependent Claim 20 words

Apparatus as claimed in claim 21, wherein the means for oscillating the velocity of the jet comprises a hydro-acoustic oscillator.

Claim 27

Dependent Claim 13 words

Apparatus as claimed in claim 24, wherein the oscillator comprises an organ-pipe oscillator.

Claim 28

Dependent Claim 13 words

Apparatus as claimed in claim 24, wherein the oscillator comprises a Helmholtz oscillator.

Claim 29

Dependent Claim 21 words

Apparatus as claimed in claim 21, wherein the means for oscillating the velocity of the jet comprises a fluid oscillator valve.

Claim 30

Dependent Claim 110 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) a liquid jet nozzle for discharging a liquid jet, said cavitating liquid jet nozzle having a housing for receiving a liquid, said housing having an interior chamber contracting to a narrower outlet orifice; b) a Helmholtz oscillator chamber situated in tandem with the liquid jet nozzle for oscillating the liquid jet at a Strouhal number within the range of from about 0.2 to about 1.2, said outlet orifice of the liquid jet nozzle comprising the inlet to the Helmholtz oscillator chamber and said Helmholtz oscillator chamber having a discharge orifice for discharging the pulsed liquid jet.

Claim 31

Dependent Claim 110 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) a liquid jet nozzle for discharging a liquid jet, said cavitating liquid jet nozzle having a housing for receiving a liquid, said housing having an interior chamber contracting to a narrower outlet orifice; b) a Helmholtz oscillator chamber situated in tandem with the liquid jet nozzle for oscillating the liquid jet at a Strouhal number within the range of from about 0.2 to about 1.2, said outlet orifice of the liquid jet nozzle comprising the inlet to the Helmholtz oscillator chamber and said Helmholtz oscillator chamber having a discharge orifice for discharging the pulsed liquid jet.

Claim 32

Dependent Claim 27 words

Apparatus as claimed in claim 28, wherein a portion of the volume of the Helmholtz oscillator chamber is located in an annular space surrounding said outlet orifice.

Claim 33

Dependent Claim 147 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) a liquid jet nozzle for discharging a liquid jet, said liquid jet nozzle having a housing for receiving a liquid, said housing have an interior chamber contracting to a narrower outlet orifice; b) a Helmholtz oscillator chamber situated in tandem with the liquid jet nozzle for oscillating the liquid jet at a Strouhal number within the range of from about 0.2 to 1.2, said outlet orifice of the liquid jet nozzle comprising the inlet to the Helmholtz oscillator chamber and said Helmholtz oscillator chamber having a discharge orifice; and c) a diffusion chamber situated in tandem with the Helmholtz oscillator chamber, said discharge orifice of the Helmholtz oscillator chamber comprising the inlet to the diffuser chamber, said diffusion chamber contracting to a narrower jet-forming orifice and smoothing the inflow to the jet-forming orifice.

Claim 34

Dependent Claim 147 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) a liquid jet nozzle for discharging a liquid jet, said liquid jet nozzle having a housing for receiving a liquid, said housing have an interior chamber contracting to a narrower outlet orifice; b) a Helmholtz oscillator chamber situated in tandem with the liquid jet nozzle for oscillating the liquid jet at a Strouhal number within the range of from about 0.2 to 1.2, said outlet orifice of the liquid jet nozzle comprising the inlet to the Helmholtz oscillator chamber and said Helmholtz oscillator chamber having a discharge orifice; and c) a diffusion chamber situated in tandem with the Helmholtz oscillator chamber, said discharge orifice of the Helmholtz oscillator chamber comprising the inlet to the diffuser chamber, said diffusion chamber contracting to a narrower jet-forming orifice and smoothing the inflow to the jet-forming orifice.

Claim 35

Independent Claim 103 words

A method of eroding a submerged solid surface with a liquid jet, comprising the steps of: a) forming a liquid jet by passing a liquid through a hydro-acoustic oscillator having a submerged nozzle; b) oscillating the velocity of the jet at the resonant frequency of said oscillator, said frequency corresponding to a Strouhal number within the range of from about 0.2 to about 1.2; c) amplifying the jet velocity oscillations by providing the exit nozzle with a contour adapted to provide feedback of the velocity oscillations in the jet to the oscillator; and d) impinging the pulsed jet against the submerged solid surface.

Claim 36

Independent Claim 103 words

A method of eroding a submerged solid surface with a liquid jet, comprising the steps of: a) forming a liquid jet by passing a liquid through a hydro-acoustic oscillator having a submerged nozzle; b) oscillating the velocity of the jet at the resonant frequency of said oscillator, said frequency corresponding to a Strouhal number within the range of from about 0.2 to about 1.2; c) amplifying the jet velocity oscillations by providing the exit nozzle with a contour adapted to provide feedback of the velocity oscillations in the jet to the oscillator; and d) impinging the pulsed jet against the submerged solid surface.

Claim 37

Dependent Claim 14 words

A method as claimed in claim 31, wherein the oscillator comprises an organ-pipe oscillator.

Claim 38

Dependent Claim 14 words

A method as claimed in claim 31, wherein the oscillator comprises a Helmholtz oscillator.

Claim 39

Independent Claim 172 words

A method of eroding a submerged solid surface with a liquid jet, comprising the steps of: a) forming a liquid jet structured into discrete, spaced apart vortices by passing a liquid through a. hydro- acoustic organ-pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a first portion with a contraction contour followed by a substantially cylindrical portion having its upstream end adjacent to said first portion, the junction of said first portion and said cylindrical portion forming a sharp edge, said cylindrical portion extending for a length sufficient to place its downstream end adjacent to an imaginary surface defining the outer envelope of the developing ring vortex flow; b) oscillating the velocity of the jet at the resonant frequency of said-chamber, said frequency corresponding to a Strouhal number within the range of from about 0.2 to about 1.2; c) amplifying the jet velocity oscillations by providing feedback of the velocity oscillations in the jet to the oscillator chamber; and d) impinging the pulsed jet against the submeged solid surface.

Claim 40

Independent Claim 172 words

A method of eroding a submerged solid surface with a liquid jet, comprising the steps of: a) forming a liquid jet structured into discrete, spaced apart vortices by passing a liquid through a. hydro- acoustic organ-pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a first portion with a contraction contour followed by a substantially cylindrical portion having its upstream end adjacent to said first portion, the junction of said first portion and said cylindrical portion forming a sharp edge, said cylindrical portion extending for a length sufficient to place its downstream end adjacent to an imaginary surface defining the outer envelope of the developing ring vortex flow; b) oscillating the velocity of the jet at the resonant frequency of said-chamber, said frequency corresponding to a Strouhal number within the range of from about 0.2 to about 1.2; c) amplifying the jet velocity oscillations by providing feedback of the velocity oscillations in the jet to the oscillator chamber; and d) impinging the pulsed jet against the submeged solid surface.

Claim 41

Dependent Claim 24 words

A method as claimed in claim 34, wherein said frequency corresponds to a Strouhal number within the range of from about 0.3 to 0.8.

Claim 42

Independent Claim 84 words

A method of oscillating the instantaneous boundary pressure at a submerged surface, comprising the steps of: a) forming a high velocity, submerged liquid jet; b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the jet forms into discrete, spaced apart vortices; c) impinging the discrete vortices against the submerged surface, whereby the instantaneous boundary pressure is reduced during each discrete time interval that one of the vortices passes adjacent said surface.

Claim 43

Independent Claim 84 words

A method of oscillating the instantaneous boundary pressure at a submerged surface, comprising the steps of: a) forming a high velocity, submerged liquid jet; b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the jet forms into discrete, spaced apart vortices; c) impinging the discrete vortices against the submerged surface, whereby the instantaneous boundary pressure is reduced during each discrete time interval that one of the vortices passes adjacent said surface.

Claim 44

Independent Claim 92 words

A method of removing the chips created at a submerged surface by a mechanical rotating roller bit drill, comprising the steps of: a) contacting the submerged surface with said drill, whereby at least a portion of the surface is fragmented into chips; b) forming a high velocity, submerged liquid jet; c) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the jet forms into discrete,. spaced apart vortices; and d) impinging the discrete vortices against said portion of the surface.

Claim 45

Independent Claim 92 words

A method of removing the chips created at a submerged surface by a mechanical rotating roller bit drill, comprising the steps of: a) contacting the submerged surface with said drill, whereby at least a portion of the surface is fragmented into chips; b) forming a high velocity, submerged liquid jet; c) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the jet forms into discrete,. spaced apart vortices; and d) impinging the discrete vortices against said portion of the surface.

Claim 46

Independent Claim 19 words

A method as claimed in claims 36 or 37, wherein the jet velocity is oscillated by a mechanical oscillator.

Claim 47

Dependent Claim 23 words

. A method as claimed.in claims 36 or 37, wherein the jet velocity is oscillated by dircting the liquid through a hydroacoustic oscillator.

Claim 48

Independent Claim 24 words

A method as claimed in claims 36 or 37, wherein the jet velocity is oscillated by directing the liquid through a hydroacoustic organ-pipe oscillator.

Claim 49

Independent Claim 24 words

A method as claimed in claims 36 or 37, wherein the jet velocity is oscillated by directing the liquid through a hydroacoustic Helmholtz oscillator.

Claim 50

Dependent Claim 143 words

Apparatus for producing a submerged pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising: a hydro-acoustic organ-pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a portion with a curved contour followed by a substantially frusto-conical portion having its upstream end adjacent to said curved portion, the junction of said curved portion and said frusto-conical portion forming sharp edge, said frusto-conical portion extending for a length sufficient to place its downstream end adjacent to an imaginary surface defining the outer envelope of the developing ring vortex flow, said edge being formed sufficiently sharp and said frusto-conical portion extending sufficiently long to provide feedback of the velocity oscillations in the jet to the oscillator chamber, wherein the resonant frequency of the chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.8.

Claim 51

Dependent Claim 143 words

Apparatus for producing a submerged pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising: a hydro-acoustic organ-pipe oscillator chamber having a submerged exit nozzle, said exit nozzle having a portion with a curved contour followed by a substantially frusto-conical portion having its upstream end adjacent to said curved portion, the junction of said curved portion and said frusto-conical portion forming sharp edge, said frusto-conical portion extending for a length sufficient to place its downstream end adjacent to an imaginary surface defining the outer envelope of the developing ring vortex flow, said edge being formed sufficiently sharp and said frusto-conical portion extending sufficiently long to provide feedback of the velocity oscillations in the jet to the oscillator chamber, wherein the resonant frequency of the chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.8.

Claim 52

Dependent Claim 136 words

Apparatus as claimed in claim 42, wherein the tangent to said curved portion of the exit nozzle at the junction of said curved portion and said'frusto-conical portion defines the exit. angle, measured in reference to the longitudinal centerline of the-nozzle, and said exit angle is at least 30°, and wherein said imaginary surface is defined by the equation Y = AS n X , whose origin is located in the plane extending through said junction at a distance from the axis of the nozzle equal to the contracted radius of the jet,, wherein X and Y are-the Cartesian coordinates and the Y axis passes through said origin and is normal to the axis of the nozzle, S is the critical Strouhal number, and A and n are constants determined by the fluid properties of the liquid.

Claim 53

Dependent Claim 166 words

Apparatus for producing a submerged-pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising: a hydro-acoustic organ pipe oscillator.chamber having a submerged exit nozzle, said exit nozzle having a portion with a curved contour followed by a portion with a substantially straight contour, said straight contour portion extending for a length sufficient to place its downstream end adjacent to an imaginary surface defining the outer envelope of the developing ring vortex flow, the tangent to said curved portion at the junction of said curved portion and said straight portion defining an exit angle, measured in reference to the longitudinal centerline of the nozzle, said exit angle being less than about 30°, wherein the junction of said curved portion and said straight portion defines an abrupt discontinuity in slope, in the form of a step, said step being sufficiently large and said straight contour portion extending for a sufficient length to provide feedback of the velocity oscillations in the jet to the oscillator chamber.

Claim 54

Dependent Claim 166 words

Apparatus for producing a submerged-pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising: a hydro-acoustic organ pipe oscillator.chamber having a submerged exit nozzle, said exit nozzle having a portion with a curved contour followed by a portion with a substantially straight contour, said straight contour portion extending for a length sufficient to place its downstream end adjacent to an imaginary surface defining the outer envelope of the developing ring vortex flow, the tangent to said curved portion at the junction of said curved portion and said straight portion defining an exit angle, measured in reference to the longitudinal centerline of the nozzle, said exit angle being less than about 30°, wherein the junction of said curved portion and said straight portion defines an abrupt discontinuity in slope, in the form of a step, said step being sufficiently large and said straight contour portion extending for a sufficient length to provide feedback of the velocity oscillations in the jet to the oscillator chamber.

Claim 55

Dependent Claim 93 words

Apparatus as claimed in claim 44, wherein said imaginary surface is defined by the equation Y = AS n X, whose origin is located in the plane extending through said junction at a distance from the axis of the nozzle equal to the contracted radius of the jet, wherein X and Y are the Cartesian coordinates and the Y axis passes through said origin and is normal to the axis of the -nozzle, S is the critical Strouhal number, and A and n are. constants determined by the fluid properties of the liquid.

Claim 56

Dependent Claim 77 words

Apparatus as claimed in claims 42 or 45, wherein the overall length of the organ-pipe oscillator chamber lies within the range of from about (2N-1/4) D/MS to about 2 D/MS where N is the resonant mode number, D is the diameter of the frusto-conical portion at its upstream end, M is the Mach number of the jet, and S is the Strouhal number, and wherein S is within the range of from about 0.3 to about 0.8.

Claim 57

Dependent Claim 59 words

Apparatus as claimed in claims 42 or 45, wherein at least two nozzles supplied from the same plenum are provided, at least one of said nozzles being larger than the other, and wherein the sizes of the nozzles are selected to supply a preselected total discharge, with the larger nozzle exciting a lower organ-pipe mode than the smaller nozzle.

Claim 58

Independent Claim 70 words

A method of generating sound waves at discrete frequencies, comprising the steps of: a) forming a liquid jet by directing a liquid through an orifice; and b) oscillating the velocity of the jet at a Strouhal number within the range of from about O.2 to about 1.2, wherein the jet velocity is oscillated by hydrodynamic and acoustic interactions in an organ-pipe oscillator, said orifice forming the exit of said oscillator.

Claim 59

Independent Claim 70 words

A method of generating sound waves at discrete frequencies, comprising the steps of: a) forming a liquid jet by directing a liquid through an orifice; and b) oscillating the velocity of the jet at a Strouhal number within the range of from about O.2 to about 1.2, wherein the jet velocity is oscillated by hydrodynamic and acoustic interactions in an organ-pipe oscillator, said orifice forming the exit of said oscillator.

Claim 60

Dependent Claim 22 words

A.method as.claimed in claim 48, wherein said orifice is surrounded by a fluid, whereby the sound waves are formed in the fluid.

Claim 61

Dependent Claim 39 words

A method as claimed in claim 49, wherein the. liquid jet forms into discrete, spaced apart vortices, and wherein vapor cavitites of the liquid are formed in the vortices and then collapse, thereby augmenting the generation of sound waves.

Claim 62

Independent Claim 88 words

A method of generating sound waves at discrete frequencies, comprising the steps of: a) forming a high velocity, submerged liquid jet; and b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, the jet velocity being oscillated by hydrodynamic and acoustic interactions in a Helmholtz oscillator, wherein the jet forms into discrete, spaced apart vortices, and wherein vapor cavities of the liquid are formed in the vortices and then collapse, thereby augmenting the generation of sound waves.

Claim 63

Independent Claim 88 words

A method of generating sound waves at discrete frequencies, comprising the steps of: a) forming a high velocity, submerged liquid jet; and b) oscillating the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2, the jet velocity being oscillated by hydrodynamic and acoustic interactions in a Helmholtz oscillator, wherein the jet forms into discrete, spaced apart vortices, and wherein vapor cavities of the liquid are formed in the vortices and then collapse, thereby augmenting the generation of sound waves.

Claim 64

Dependent Claim 154 words

Apparatus for producing a submerged pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising: a hydro-acoustic organ-pipe oscillator chamber having a submerged exit nozzle., said exit nozzle having a first portion having a contraction contour followed by a substantially cylindrical portion having its upstream end adjacent to said first portion, the junction of said first portion and. said cylindrical portion forming a sharp edge, said cylindrical portion being followed immediately by a curved surface tangent to the downstream end of said cylindrical portion and further tangent to an imaginary surface defining the outer envelope of the developing ring vortex flow, wherein said sharp edge, said cylindrical portion and said curved surface- are adapted to provide feedback of the velocity oscillations in the jet to the oscillator chamber, and wherein the resonant frequency of the chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.8.

Claim 65

Dependent Claim 154 words

Apparatus for producing a submerged pulsed liquid jet which is structured into discrete, spaced apart ring vortices, comprising: a hydro-acoustic organ-pipe oscillator chamber having a submerged exit nozzle., said exit nozzle having a first portion having a contraction contour followed by a substantially cylindrical portion having its upstream end adjacent to said first portion, the junction of said first portion and. said cylindrical portion forming a sharp edge, said cylindrical portion being followed immediately by a curved surface tangent to the downstream end of said cylindrical portion and further tangent to an imaginary surface defining the outer envelope of the developing ring vortex flow, wherein said sharp edge, said cylindrical portion and said curved surface- are adapted to provide feedback of the velocity oscillations in the jet to the oscillator chamber, and wherein the resonant frequency of the chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.8.

Claim 66

Dependent Claim 95 words

Apparatus as claimed in claim 52, wherein said imaginary surface is defined by the equation Y = AS n X , whose origin is located in the plane extending through said. sharp edge at a distance from the axis of the nozzle equal to the contracted radius of the jet, wherein X and Y are the Cartesian coordinates and the Y axis passes through said origin and is normal to the axis of the nozzle, S is the critical Strouhal number, and A and n are constants determined by the fluid properties of the liquid.

Claim 67

Dependent Claim 30 words

Apparatus as claimed in claim 53, wherein A = 1.15 and n = 3/2 for water, at a Reynolds number on the order of about 7 x 10 5 .

Claim 68

Dependent Claim 26 words

Apparatus as claimed in claim 52, wherein said curved surface is defined by a circular arc whose radius is determined by said two points of tangency.

Claim 69

Dependent Claim 41 words

Apparatus as claimed in claim 52, wherein the length of said substantially cylindrical portion is about 60 % of the distance between said sharp edge and the point of intersection.of the imaginary extension of said cylindrical portion with said imaginary surface.

Claim 70

Dependent Claim 48 words

Apparatus as claimed in claim 56, wherein the distance along said imaginary surface betwen the point of tangency of the curved surface with said imaginary surface and said point of intersection is equal to about 40 % of the distance betwen.said sharp edge and said point of intersection.

Claim 71

Dependent Claim 44 words

- Apparatus as- claimed in claim 52 or 57, wherein said curved surface extends beyond said point of tangency with said imaginary surface a distance equal to about 10 % to about 20 % of the diameter of the nozzle at said sharp edge.

Claim 72

Dependent Claim 74 words

Apparatus as claimed in claim 52, wherein the tangent to said contraction contour at said sharp edge defines an exit angle, measured in reference to the longitudinal centerline of the nozzle, said exit angle being less than about 30°, and wherein said sharp edge defines . an abrupt discontinuity in slope, in the form of a step, whereby the diameter of said cylindrical portion is larger than the nozzle diameter at said sharp edge.

Claim 73

Dependent Claim 40 words

Apparatus as claimed in claims 42 or 52, wherein the resonant frequency of said chamber corresponds to a Strouhal number within the range of from about 0.3 to about 0.4 and the resonant mode number of the chamber is 1.

Claim 74

Dependent Claim 39 words

Apparatus as claimed in claims 42 or 52, wherein the value of the resonant mode number of the chamber is selected such that the Strouhal number is at its minimum value, provided it is not less than about 0.3.

Claim 75

Dependent Claim 97 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) hydro-acoustic nozzle means for oscillating the velocity of a first liquid jet, said first liquid jet being discharged within a chamber; and b) at least one cavitating liquid jet nozzle having a housing for receiving a liquid, said housing having an interior chamber contracting to a narrower discharge orifice for discharging a second liquid jet within said chamber such that the velocity of said second liquid jet is pulsed by the action of the pulsed first liquid jet, thereby increasing its erosive intensity.

Claim 76

Dependent Claim 97 words

Apparatus for producing a pulsed liquid jet for eroding a solid surface, comprising: a) hydro-acoustic nozzle means for oscillating the velocity of a first liquid jet, said first liquid jet being discharged within a chamber; and b) at least one cavitating liquid jet nozzle having a housing for receiving a liquid, said housing having an interior chamber contracting to a narrower discharge orifice for discharging a second liquid jet within said chamber such that the velocity of said second liquid jet is pulsed by the action of the pulsed first liquid jet, thereby increasing its erosive intensity.

Claim 77

Dependent Claim 57 words

Apparatus as claimed in claim 62, further comprising a roller bit for drilling a hole in the solid surface, at least two extension arms for supplying drilling fluid to the hole, and at least two cavitating liquid jets situated at the extremities of said extension arms, and wherein said chamber comprises the hole filled with drilling fluid.

Claim 78

Independent Claim 106 words

A method of eroding a solid surface with a high velocity liquid jet, comprising the steps of: forming a high velocity liquid jet; pulsing the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2; and impinging the pulsed jet against the solid surface, wherein the liquid jet is pulsed by situating it within a chamber submerged in a liquid, said chamber containing a further liquid jet which is pulsed at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the oscillation of' the further liquid jet induces oscillation of the liquid jet.

Claim 79

Independent Claim 106 words

A method of eroding a solid surface with a high velocity liquid jet, comprising the steps of: forming a high velocity liquid jet; pulsing the velocity of the jet at a Strouhal number within the range of from about 0.2 to about 1.2; and impinging the pulsed jet against the solid surface, wherein the liquid jet is pulsed by situating it within a chamber submerged in a liquid, said chamber containing a further liquid jet which is pulsed at a Strouhal number within the range of from about 0.2 to about 1.2, whereby the oscillation of' the further liquid jet induces oscillation of the liquid jet.

Enhancing liquid jet erosion

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