Patent EA-003436-B1 (EA)
Title: Method and apparatus for producing a high-velocity particle stream
Inventor: PAO Y H MICHAEL
IPC: B24C5/04
Filed: 1998-07-09
Abstract: 1. A method for producing a stream of particles moving at high velocity in a chamber, comprising the steps of: (i) accelerating a plurality of particles to a subsonic velocity using one or more jets of gas to generate a stream of particles; (ii) accelerating said particles to a higher velocity using one or more jets of liquid by contacting said stream of particles at an oblique angle with one or more jets of ultra-high pressure water within the chamber; (iii) inducing spiral motion to said particles by the injection of one or more jets of fluid. 2. The method of claim 1, comprising the additional step of: amplifying said radial motion to said particles by narrowing the internal radius of the chamber. 3. The method of Claim 1 wherein said introduction of one or more jets of fluid occurs by injection of pressurized fluid. 4. The method of Claim 1 wherein said introduction of one or more jets of fluid occurs by passive aspiration of fluid. 5. The method of Claim 1 wherein said fluid is air. 6. A method for producing a stream of particles moving at high velocity in a chamber, comprising the steps of: (i) accelerating a plurality of particles to a subsonic velocity using one or more jets of gas to generate a stream of particles; thereafter, (ii) accelerating said particles to a higher velocity using one or more jets of liquid by contacting said stream of particles with one or more jets of ultra-high pressure water within the chamber; thereafter, (iii) inducing spiral motion to said particles by narrowing the internal radius of the chamber. 7. A method for producing a stream of particles moving at high velocity in a chamber, comprising the steps of: (i) accelerating particles to subsonic velocity using at least one jet of gas; thereafter, (ii) accelerating said particles to a higher velocity using at least one jet of liquid by contacting said stream at an oblique angle with at least one jet of ultra-high pressure water within the chamber; (iii) inducing radial motion to said particles. 8. The method of claim 7, comprising the additional step of: amplifying said radial motion to said particles. 9. The method of claim 7, comprising the additional step of: inducing spreading of said stream. 10. The method of claim 7 wherein said abrasive particle stream is accelerated to a velocity of greater than about 182.9 m/sec. 11. An apparatus for producing a fluid jet stream of abrasive particles in a fluid matrix, comprising: (i) a mixing chamber; (ii) an air/particle inlet means at one end of said mixing chamber for delivering an air/particle stream into the mixing chamber at subsonic velocity; (iii) one or more ultra-high pressure fluid inlet means fluidly engaging said mixing chamber for accelerating said air/particle stream to a higher velocity; and (iv) one or more air inlet means upstream, at or downstream from the water inlet means and fluidly engaged to the mixing chamber for inducing or amplifying radial flow to said stream. 12 An apparatus for producing a fluid jet stream of abrasive particles in a fluid matrix, comprising: (i) a mixing chamber; (ii) an air/particle inlet means at one end of said mixing chamber for delivering an air/particle stream into the mixing chamber at subsonic velocity; (iii) one or more ultra-high pressure liquid inlet means fluidly and obliquely engaging said mixing chamber for accelerating said air/particle stream to a higher velocity; and (iv) means for inducing or amplifying spiral flow to said air/particle stream. 13. The apparatus of Claim 12 wherein said means for inducing or amplifying radial flow is a groove placed on the inner wall of said mixing chamber. 14 The apparatus in Claim 12 wherein said mixing chamber comprises a converging portion and a diverging portion. 15. The apparatus in Claim 12 wherein said mixing chamber comprises a diverging portion. 16. The apparatus in Claim 12 wherein said mixing chamber comprises a converging portion and a focusing tube. 17. A method for generating an ultra-high pressure fluid-abrasive stream, comprising: providing a pressurized stream of abrasive particles and air to an inlet of a nozzle having a proximal converging region and a distal diverging region; accelerating the pressurized stream of abrasive particles to a first velocity of more than 91.44 m/sec by passing the pressurized stream through the nozzle, the pressurized stream of abrasive particles entering a mixing chamber; introducing an ultra-high pressure liquid jet into the mixing chamber, the ultra-high pressure liquid jet contacting and accelerating the pressurized stream of abrasive particles to a second velocity that is higher than the first velocity to generate an ultra-high pressure fluid-abrasive stream; and discharging the ultra-high pressure fluid-abrasive stream through an exit orifice. 18. The method of Claim 17 further comprising: selectively allowing and preventing the flow of abrasive particles through the inlet of the nozzle. 19. The method of Claim 17 further comprising: selectively allowing and preventing the flow of the ultra-high pressure liquid jet upstream of the mixing chamber. 20. An apparatus for generating a fluid jet containing abrasive particles, comprising: a source of abrasive particles pressurized by a gas and coupled to an inlet of a first nozzle to provide a pressurized stream of abrasive particles to the inlet of the first nozzle, the first nozzle having a proximal converging region coupled to a distal diverging region; a mixing chamber in fluid communication with an outlet of the first nozzle positioned adjacent to the distal diverging region of the first nozzle, the pressurized stream of abrasive particles passing through and being accelerated by the first nozzle to a velocity of over 91.44 m/sec and being discharged into the mixing chamber; a fluid inlet nozzle coupled in fluid communication with the mixing chamber and with a source of ultra-high pressure liquid, an ultra-high pressure liquid jet being discharged through the fluid inlet nozzle at a sufficient velocity to entrain and accelerate the pressurized stream of abrasive particles; an exit tube having an inlet in fluid communication with the mixing chamber and an outlet through which the ultra-high pressure fluid jet containing abrasive particles is discharged. 21. The apparatus of Claim 20 wherein the mixing chamber is provided with a first inlet coupled to a source of gas to supply a stream of gas into the mixing chamber to improve the distribution of the abrasive particles in the ultra-high pressure fluid jet. 22. The apparatus of Claim 21 further comprising: a first valve coupled to the first nozzle to selectively start and stop the flow of the pressurized stream of abrasive particles into the first nozzle; a second valve coupled to the fluid inlet nozzle to selectively start and stop the flow of ultra-high pressure liquid into the mixing chamber; and a third valve coupled to the first inlet to selectively start and stop the flow of gas into the mixing chamber. 23. The apparatus of Claim 20 wherein the fluid inlet nozzle comprises an orifice aligned with a passageway that extends from the orifice to an opening in the apparatus along a path on which the ultra-high pressure fluid jet enters the mixing chamber. 24. The apparatus of Claim 20 further comprising an annular feed ring in fluid communication with a plurality of fluid inlet nozzles that in turn are in fluid communication with the mixing chamber, a volume of ultra-high pressure liquid being provided to the annular feed ring and following through the plurality of fluid inlet nozzles into the mixing chamber. 25. The apparatus of Claim 20 wherein the mixing chamber is provided with a second orifice in fluid communication with an anti-corrosion source of chemicals.