Abstract A plasma-spray burner and process for operating the same includes a longitudinally reciprocable cathode disposed upstream of a nozzle which serves as an anode, a power source being electrically connected therebetween. The cathode is movable between at least two positions one of the positions serving to seal the inlet to the nozzle whereby the flow of operational gas through the nozzle is terminated. Means are also provided for synchronously controlling the movement of the cathode in conjunction with the supply of power to the cathode and anode in a pulsed fashion whereby power will be supplied when the cathode is moved to a position which permits the flow of gas to occur through the nozzle, an arc thereby existing between the cathode and anode, and wherein such power will be terminated when the cathode is moved to the position which seals the nozzle inlet.
A process for operating a plasma-spray burner in which an arc exists between a cathode and a nozzle acting as anode and transmitting an operational gas, the arc serving to generate the plasma jet containing the material to be sprayed in particulate form, comprising the steps of: subjecting the operational gas to a pressure exceeding two atmospheres prior to entering said nozzle; providing an arc-burning current which exceeds one thousand amperes; and pulsing said gas flow through said nozzle and synchronously pulsing said arc-burning current through said nozzle.
Claim 2
Dependent Claim
88 words
A process for operating a plasma-spray burner in which an arc exists between a cathode and a nozzle acting as anode and transmitting an operational gas, the arc serving to generate the plasma jet containing the material to be sprayed in particulate form, comprising the steps of: subjecting the operational gas to a pressure exceeding two atmospheres prior to entering said nozzle; providing an arc-burning current which exceeds one thousand amperes; and pulsing said gas flow through said nozzle and synchronously pulsing said arc-burning current through said nozzle.
Claim 3
Dependent Claim
26 words
A process as set forth in claim 1, wherein said gas flow through said nozzle and said arc-burning current will be substantially zero between said pulses.
Claim 4
Dependent Claim
57 words
A process as set forth in claim 1, wherein said pressure impressed upon said operational gas will be equal to or greater than 2 atm. and less than or equal to 20 atm. and said arc-burning current will be equal to or greater than 1 kamp and less than or equal to 20 kamp. during a pulse.
Claim 5
Dependent Claim
57 words
A process as set forth in claim 2, wherein for an operational pressure of 20 atm. and an arc-burning current of 20 kamp., said pulse duration encompassing said gas flow and arc discharge is less than 10 msec and said duration of time wherein there is no gas flow and arc discharge is greater than 100 msec.
Claim 6
Dependent Claim
25 words
A process as set forth in claim 1, wherein said operational gas being utilized is air when spraying said materials which are insensitive to oxidation.
Claim 7
Dependent Claim
45 words
A process as set forth in claim 1, wherein said material to be sprayed is in particulate form, said particles ranging in size from 10 to 100 microns, and is added to said operational gas prior to said entrance of said gas into said nozzle.