Heat-plasma-jet generator capable of conducting plasma spray or heat-plasma CVD coating in a relatively wide area

• US 5,235,160 A
• Filed: 03/20/1991
• Issued: 08/10/1993
• Est. Priority Date: 03/22/1990
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Suzuki, Shigeo, Nojima, Takashi, Kurokawa, Hideo
• Primary Examiner(s): Paschall, Mark H.
• Application Number:
  US07/671,922
• Time in Patent Office: 874 Days
• Field of Search: 219/121.59, 219/121.52, 219/123, 219/76.16, 219/121.47, 219/121.54, 219/121.56, 219/75, 219/136, 427/34
• US Class Current: 219/121.52
• CPC Class Codes: H05H 1/34 Details, e.g. electrodes, nozzles
• CPC Class Codes: H05H 1/42 with provisions for introducing materials into the plasma, e.g. powder, liquid arc stabilising or constricting arrangements H05H1/3405; coaxial protecting fluids H05H1/341; electrostatic spraying, spraying apparatus with means for charging the spray electrically B05B5/00 ; cf. B23K9/324, B05B7/22

Abstract

In a heat-plasma-jet, an arc is initially generated between opposed endless ends of a pair of electrodes and is moved along the opposed endless ends of the electrodes by generating magnetic fields having the same polarity at the opposed ends of the electrodes. Thereafter, a plasma generating gas is supplied into a region in which the arc is generated.

Claims

1. A heat-plasma-jet generator comprising:

a gas inlet housing for introducing a plasma generating gas therethrough;

a pair of electrodes disposed below said gas inlet housing and having respective opposed edges extending in endless paths for generating an arc therebetween, said electrodes having a space defined therebetween for introduction of the plasma generating gas thereinto;

exciting coils wound around respective said electrodes for generating, in an around said electrodes, magnetic fields having the same polarity at said opposed edges of said electrodes;

a plasma outlet housing disposed below said electrodes for jetting plasma therefrom, said plasma outlet housing having a raw material supply port formed therein for supplying raw material into the plasma;

a DC power source for applying a DC current to said electrodes; and

arc detecting means for detecting an arc disposed at opposite ends of said space defined between both said electrodes, wherein the polarities of said electrodes are reversed by said DC power source in response to signals outputted from said arc detecting means so that said arc moves back and forth between said arc detecting means.

2. A heat-plasma-jet generator comprising:

a gas inlet housing for introducing a plasma generating gas therethrough;

a pair of flat electrodes disposed below said gas inlet housing, spaced from each other at a predetermined interval, and having a space defined therebetween for introduction of the plasma generating gas thereinto, said electrodes further having respective cooling water passages formed therein;

insulating members of a non-magnetic material disposed below said electrodes;

ferromagnetic members disposed below said insulating members;

a magnet disposed above said space defined between said electrodes and extending in one direction in which said electrodes extend;

arc detecting means disposed at opposite ends of said space in said direction for detecting an arc

a DC power source for applying a DC current to said electrodes and for reversing polarities of said electrodes in response to signals outputted from said arc detecting means; and

a plasma outlet housing disposed below said ferromagnetic members and having at least one raw material supply port formed therein for supplying raw material into a plasma to be generated.

3. A heat-plasma-jet generator comprising:

a gas inlet housing for introducing a plasma generating gas therethrough;

a cathode disposed inside said gas inlet housing having a lower elliptical open end;

an anode disposed below said gas inlet housing having an upper elliptical open end spaced below said lower open end of said cathode, said upper open end being larger than said lower open end, and said upper open end and said lower open end defining a space therebetween for introduction of the plasma generating gas thereinto;

a raw material supply means for supplying a raw material accommodated in and coaxially aligned with said cathode;

a permanent magnet disposed about said cathode for generating magnetic fields crossing said space between said upper and lower open ends; and

a DC power source connected to said cathode and said anode for applying a DC current thereto.

4. A heat-plasma-jet generator, comprising:

a gas inlet housing for introducing a plasma generating gas therethrough;

a cathode disposed inside said gas inlet housing having a lower elliptical open end;

an anode disposed below said gas inlet housing having an upper elliptical open end spaced below said lower open end of said cathode, said upper open end being larger than said lower open end, and said upper open end and said lower open end defining a space therebetween for introduction of the plasma generating gas thereinto;

a raw material supply means for supplying a raw material accommodated in and coaxially aligned with said cathode;

exciting coils wound around said cathode and said anode, respectively, for generating magnetic fields in and around said cathode and said anode; and

a DC power source connected to said cathode and said anode for applying a DC current thereto.