PLASMA-JET GENERATOR FOR VERSATILE APPLICATIONS

• US 3,684,911 A
• Filed: 08/25/1970
• Issued: 08/15/1972
• Est. Priority Date: 08/25/1970
• Status: Expired due to Term

• Current Assignee: Carmelo (Merano Caccamo, Giancarlo (Merano Perugini, Giorgio Marcato, Luigi (Merano Belotti
• Original Assignee: Carmelo (Merano Caccamo, Giancarlo (Merano Perugini, Giorgio Marcato, Luigi (Merano Belotti
• Inventors: Perugini, Giancarlo (Merano, Marcato, Giorgio, Belotti, Luigi (Merano, Caccamo, Carmelo (Merano
• Primary Examiner(s): Kominski, John
• Application Number:
  US05/066,852
• Time in Patent Office: 721 Days
• Field of Search: 313/23,231 219/74,75,121P
• US Class Current: 313/231.41
• CPC Class Codes: B05B 7/226 the material being originally a particulate material
• CPC Class Codes: H05H 1/32 using an arc H05H1/28 takes precedence

Abstract

Improvement of the plasma-jet generator described in U.S. Pat. No. 3,390,292 to Perugini, by improving the water cooled anodic surface, and an anode adapter using an interchangeable set of electrodes forming and stabilizing the plasma-jets. This provided higher cooling efficiency and higher operative resistance of the anode and wider suitability of the generator in forming plasmajets of higher power and wider utility.

Claims

1. In a plasma-jet generator, comprising a cathode, an interelectrodic electroinsulating element, an anode, said cathode and anode being coaxial electrodes, means for injecting a stream of water against the rear of the cathode, multiradial directrixes determined by the rear configuration of the cathode for passage of water to circumferential water passages in the electroinsulating element for coNveying the cooling water through said element to the anode, said passages being coaxial to the electrodes and equidirectional to the plasma-jet, and means for passing cooling water around the anode to cool the same, and means for collecting the water leaving out the anode into a circular discharge collecting sump so that the water entering the anode and the discharge collecting sump are adjacent each other though separated from each other by an annular diaphragm supporting the anode;

the improvement comprising a resistant anode, which on an integral copper body and in a coaxial position to a central nozzle, said nozzle has a truncated conical ring of holes in a first portion of said anode through which the cooling water flows circumferentially coaxially and equidirectionally with the plasma-jet and with a centripetal movement, then striking and cooling the inner wetted surface of said anode and finally discharging through a transverse groove, according to a multiradial centrifugal and oblique direction, towards a discharge collecting sump.

2. The plasma jet generator of claim 1, wherein the anode is substituted by an insert comprising at least two pieces, the first of which is an anode adapter and the second of which is the true anode, wherein at least the anode adapter, having in its center a cylindrical or frusto-conical hole, is also provided with a double frusto-conical ring of holes, the central hole and the rings of holes being coaxial each other and to the plasma generator, in said insert, so that the water coming from the interelectrodic electro-insulating element is forced inside the holes of the inner frusto-conical ring towards the anode, and is discharged from the anode through the holes of the outer frusto-conical ring of the anode adapter.

3. The insert according to claim 2, wherein the anode has holes and grooves longitudinally placed in form of ring inside the body of the anode and coaxially to the nozzle of the same, so that the water flows through the holes equidirectionally with the plasma jet and flows in the grooves countercurrently to the plasma jet.

4. The insert according to claim 2, wherein the anode has only a transverse groove.

5. The plasma-jet generator of claim 1, wherein the internal conformation generated by the electrodic inserts and in contact with the arc gas presents a coaxial cylindrical cathode ending in only one tip taper, within a conical part constituting the inside of a cylindrical nozzle.

6. The plasma-jet generator of claim 5, wherein when using plasma-jets originated by a noble gas, the taper of the cathode and that of the nozzle are between 53* and 63*, and 61* and 71*, respectively.

7. The plasma-jet generator of claim 6, wherein the preferred taper values of the cathode and of the nozzle are 58* and 66*, respectively.

8. The plasma-jet generator of claim 7, wherein the tip of the cathode is cone shaped and cropped with a bending radius between 0.75 and 1.5 mm.

9. The plasma-jet generator of claim 7, wherein the bending radius is 1.25 mm.

10. The plasma-jet generator of claim 3, wherein when using plasma-jets originated by a gas selected from nitrogen, hydrogen and mixtures thereof, the taper of the cathode and that of the nozzle are between 85* and 95*, and 54* and 64*, respectively.

11. The plasma-jet generator of claim 10, wherein the preferred taper values of the cathode and of the nozzle are 90* and 59*, respectively.

12. The plasma-jet generator of claim 4, wherein for use of plasma-jets originated by gaseous mixtures selected from argon/nitrogen and argon/hydrogen, the cathode taper and that of the nozzle are between 35* and 45*, and 18* and 22*, respectively.

13. The plasma-jet generator of claim 12, wherein the preferential taper values of the cathode and of the nozzle are 40* and 20*, respectivEly.

14. The plasma-jet generator of claim 13, wherein the cone-shaped tip of the cathode is cropped with a flat face being normal with respect to the axis of said cathode, said flat face having a diameter comprised between 1.4 and 1.8 mm.

15. The plasma-jet generator of claim 14, wherein the diameter is 1.6 mm.

16. The plasma-jet generator of claim 8, wherein the position of the cathode tip is coplanar with the beginning of a cylindrical portion of the nozzle, within a variance of + or - 2mm.

17. The plasma-jet generator of claim 11, wherein the position of the cathode tip is coplanar with the beginning of a cylindrical portion of the nozzle, within a variance of + or -2 mm.

18. The plasma-jet generator of claim 14, wherein the coaxial assemblage of the cathode with respect to the nozzle is separated at a distance between 5 and 10 mm.

19. The plasma-jet generator of claim 18, wherein the separation is 6 mm.