Electrodischarge apparatus for generating low-frequency powerful pulsed and cavitating waterjets

• US 10,226,776 B2
• Filed: 06/16/2015
• Issued: 03/12/2019
• Est. Priority Date: 01/21/2015
• Status: Active Grant

• Current Assignee: VLN Advanced Technologies Inc.
• Original Assignee: VLN Advanced Technologies Inc.
• Inventors: Vijay, Mohan
• Primary Examiner(s): Valvis, Alexander
• Assistant Examiner(s): Dandridge, Christopher R
• Application Number:
  US14/741,101
• Publication Number:
  US 20160207052A1
• Time in Patent Office: 1,365 Days
• Field of Search: 239690-708, 118629
• CPC Class Codes: B05B 1/08 of pulsating nature, e.g. delivering liquid in successive separate quantities ; Fluidic oscillators
• CPC Class Codes: B05B 12/06 for effecting pulsating flow nozzles, spray head or outlet with means for generating a discharge of pulsating nature B05B1/08
• CPC Class Codes: B05B 17/0676 Feeding means
• CPC Class Codes: B05B 5/025 Discharge apparatus, e.g. electrostatic spray guns
• CPC Class Codes: B05B 5/087 Arrangements of electrodes, e.g. of charging, shielding, collecting electrodes B05B5/12, B05B5/14 take precedence; arrangements of electrodes on the discharge apparatus B05B5/0533
• CPC Class Codes: B05B 5/1616 and the arrangement comprising means for insulating a grounded material source from high voltage applied to the material
• CPC Class Codes: B08B 2203/0288 Ultra or megasonic jets
• CPC Class Codes: B08B 3/02 Cleaning by the force of jets or sprays
• CPC Class Codes: B08B 3/10 with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
• CPC Class Codes: B08B 3/12 by sonic or ultrasonic vibrations washing or rinsing machines for crockery or tableware using sonic or ultrasonic waves A47L15/13; of natural teeth, of prostheses using ultrasonic techniques similar to those used for natural teeth A61C17/20; application of ultrasonic vibrations to chemical, physical or physico-chemical processes in general B01J19/10
• CPC Class Codes: B08B 9/00 Cleaning hollow articles by methods or apparatus specially adapted thereto B08B6/00 takes precedence
• CPC Class Codes: B08B 9/0813 by the force of jets or sprays
• CPC Class Codes: E21C 45/00 Methods of hydraulic mining; Hydraulic monitors E21C25/60 takes precedence

Abstract

An electrodischarge apparatus has a nozzle that includes a discharge chamber that has an inlet for receiving water and an outlet. The apparatus has a first electrode extending into the discharge chamber that is electrically connected to one or more high-voltage capacitors. A second electrode is proximate to the first electrode to define a gap between the first and second electrodes. A switch causes the one or more capacitors to discharge across the gap between the electrodes to create a plasma bubble which expands to form a shockwave that escapes from the nozzle ahead of the plasma bubble.

Claims

1. An electrodischarge apparatus comprising:

a nozzle that includes an inlet for receiving water and an exit orifice defining an outlet, the nozzle defining a central longitudinal axis aligned with the outlet;

a first electrode extending axially along the central longitudinal axis of the nozzle and being electrically connected to one or more high-voltage capacitors, wherein the first electrode and the nozzle define an annular flow path;

a second electrode connected to the nozzle and spaced radially outward from the first electrode to define a gap across the annular flow path between the first and second electrodes;

a switch to cause the one or more capacitors to discharge across the gap between the electrodes to create a plasma bubble which expands to form a shockwave that escapes from the exit orifice ahead of the plasma bubble;

a water pump to supply the water via a hose to the discharge chamber; and

an insulated hose coupling to electrically insulate the pump from the nozzle.

2. The apparatus as claimed in claim 1 wherein the water pump pressurizes the water to create a high-speed waterjet through the nozzle.

3. The apparatus as claimed in claim 1 further comprising a reflector disposed at the inlet, the reflector being movable to act as a check valve to admit water into the discharge chamber and to reflect a shockwave generated by the discharge.

4. The apparatus as claimed in claim 1 wherein the first and second electrodes are orthogonal to the nozzle and wherein the first electrode has a planar tip and the second electrode has a pointed tip.

5. The apparatus as claimed in claim 1 wherein the first electrode has an axially aligned stem having a forward portion having diverging and converging conical portions for self-sealing against an inner insulating sleeve and wherein the electrode has a bulbous tip.

6. The apparatus as claimed in claim 2 further comprising an ultrasonic transducer for modulating the high-speed waterjet to generate a forced pulsed waterjet.

7. The apparatus as claimed in claim 6 wherein a microtip of the ultrasonic transducer is orthogonal to the first and second electrodes and wherein the microtip, the first electrode and the second electrode each terminate in a diverging section of the nozzle.

8. The apparatus as claimed in claim 7 wherein a first tip of the first electrode is pointed and a second tip of the second electrode is planar.

9. The apparatus as claimed in claim 7 wherein a first tip of the first electrode is planar and a second tip of the second electrode is planar.

10. The apparatus as claimed in claim 1 wherein the first and second electrodes are packaged in a single detachable unit that slides orthogonally into and out of the nozzle.

11. The apparatus as claimed in claim 10 further comprising a concave shaped reflector.

12. The apparatus as claimed in claim 1 wherein the first and second electrodes have detachable tips.

13. The apparatus as claimed in claim 12 wherein each of the detachable tips is held in place by a pin.

14. The apparatus as claimed in claim 1 further comprising a sheathing nozzle having a port to receive water and to generate a sheath of water defining a secondary annular jet to confine a cavitation bubble when the plasma bubble cools and to transport the cavitation bubble towards a surface to be processed.

15. The apparatus as claimed in claim 1 further comprising a plurality of ring electrodes for sequential discharges.

16. The apparatus as claimed in claim 1 wherein the hose comprises braided metal wire.

17. The apparatus as claimed in claim 1 wherein the one or more capacitors discharge a voltage that is greater than or equal to 5kV.

18. The apparatus as claimed in claim 17 wherein the hose comprises braided metal wire.

19. The apparatus as claimed in claim 1 wherein the exit orifice has a diameter of 0.5 mm to 19 mm.

20. The apparatus as claimed in claim 1 wherein the exit orifice has a diameter equal to a length of the exit orifice.