Arc heater apparatus and method for producing a diffuse arc discharge

Claim 2

Arc heater apparatus comprising, in combination, means forming a pressure vessel, means for admitting gas to be heated into the pressure vessel, means for exhausting heated gas from the pressure vessel, a first pair of axially spaced electrodes electrically insulated from each other disposed in the pressure vessel, a second pair of axially spaced electrodes electrically insulated from each other disposed in the pressure vessel, lead means for connecting the first pair of electrodes across a source of potential, other lead means for connecting the second pair of electrodes across a source of potential, the arc heater upon start-up having a first arc produced between the first pair of spaced electrodes which operates in a constricted mode and a second arc produced between the second pair of spaced electrodes which operates in a constricted mode, magnetic field means for causing both arcs to move in substantially repetitive generally closed paths between oppositely poled electrodes of a pair, the path of the second arc in general describing a cylinder and being interior to the path of the first arc, the outer exterior first arc radiating energy which is partially absorbed by gas adjacent the interior second arc thereby raising the temperature and conductivity of said last-named gas and allowing the interior second arc to undergo a transition from a constricted to a diffused mode of operation.

Claim 3

Apparatus according to claim 1 in which the arc heater is additionally characterized as having a third pair of electrodes therein spaced from each other and electrically insulated from each other, the third pair of electrodes being so located as to produce a third arc moving in a path confined within the path of the second arc, the third arc adding heat by radiation to the gas in the path of the second arc.

Claim 4

Arc heater apparatus according to claim 2 including in addition adjustable ballast means connected in series with at least one pair of the first and third pair of electrodes.

Claim 5

Arc heater apparatus according to claim 1 in which all of the electrodes are additionally characteRized as being fluid cooled.

Claim 6

Arc heater apparatus according to claim 1 in which all of the wall portions of the pressure vessel are additionally characterized as being fluid cooled.

Claim 7

An arc heater according to claim 6 wherein the means for exhausting heated gas from the arc chamber is nozzle means mounted coaxially in the arc chamber and extending through one electrode of the first pair of electrodes, and the means for generating a magnetic field includes two magnetic field coils, one of said coils being mounted around the outside of the nozzle means exterior to the means forming the enclosed arc chamber, and the other coil is mounted outside the arc chamber forming means adjacent the other electrode of the first pair of electrodes, said field coils being so energized that their magnetic fields oppose each other.

Claim 8

An arc heater according to claim 6 including an adjustable ballast means connected in circuit with each pair of electrodes to provide for stable operation of the arcs between the pairs of electrodes.

Claim 9

An arc heater according to claim 6 wherein the means forming the arc chamber includes a plurality of segmented wall portions electrically insulated from each other, each of said wall portions having a passageway there through for the flow of cooling fluid.

Claim 12

The method according to claim 10 additionally characterized as including the step of cooling the electrodes forming the arc by conducting thermal energy therefrom.

Claim 13

In an arc heater including means forming an enclosed arc chamber with means for admitting gas to be heated and exhausting heated gas, and having a pair of spaced annular electrodes adapted to be connected to terminals of opposite polarity of a source of potential to produce an arc therebetween and magnetic field means for causing the arc to move substantially continuously around and between the electrodes, means for producing an additional second arc in the arc chamber under the influence of the magnetic field, the path of the second arc extending generally parallel to the path of the first-named arc and rotating around an axis substantially coaxial with that of the first-named arc, the second arc assisting in maintaining the temperature of gas in the path of the first-named are at a value which permits the first-named arc to go into a diffused mode of operation, and means for producing a third arc having a generally cylindrical arc path within but spaced from the path of the first-named arc, the third arc supplying heat by radiation to the gas in the path of the first-named arc.

Claim 14

In an arc heater including means forming an enclosed arc chamber with means for admitting gas to be heated and exhausting heated gas, and having a pair of spaced annular electrodes adapted to be connected to terminals of opposite polarity of a source of potential to produce an arc therebetween and magnetic field means for causing the arc to move substantially continuously around and between the electrodes, means for producing an additional second arc in the arc chamber under the influence of the magnetic field, the path of the second arc extending generally parallel to the path of the first-named arc and rotating around an axis substantially coaxial with that of the first-named arc, the second arc assisting in maintaining the temperature of gas in the path of the first-named are at a value which permits the first-named arc to go into a diffused mode of operation, and means for producing a third arc having a generally cylindrical arc path within but spaced from the path of the first-named arc, the third arc supplying heat by radiation to the gas in the path of the first-named arc.

Claim 15

An arc heater comprising, in combination, a first pair of axially spaced annular electrodes of a first diameter, a second pair of substantially equally axially spaced annular electrodes of a second diameter greater than said first diameter, the second pair of annular electrodes being coaxially mounted and substantially coplanar with respect to the first pair of electrodes, a third pair of substantially equally axially spaced electrodes of a third diameter greater than said second diameter coaxially mounted with respect to the first and second pairs of electrodes, means enclosing the space between all said electrodes to form a closed arc chamber, said last-named means including means for admitting gas to be heated into the chamber and means for exhausting heated gas from the chamber, the first pair of electrodes being adapted to be connected to terminals of opposite polarity of a source of potential to produce an arc therebetween in a constricted mode of operation, the third pair of electrodes being adapted to be connected to terminals of opposite polarity of a source of potential to produce a constricted arc therebetween, the second pair of electrodes being adapted to be connected to a high current source of potential to produce an arc therebetween, magnetic field producing means so positioned with respect to all the electrodes that when energized a magnetic field is set up extending substantially radially in all directions from the axes of all the electrodes and having a strong magnetic field component transverse to all the arc paths between the first, second and third pairs of electrodes whereby the arcs between the respective pairs of electrodes are caused to move substantially continuously in annular paths around and between the electrodes, the third arc forming a rotary path around the second arc which substantially encloses the second arc and prevents loss of heat from the second arc to the walls of the means forming the arc chamber, the second arc absorbing additional heat by radiation from the first and third arcs whereby the second arc is permitted to go into a diffused mode of operation thereby increasing the enthalpy imparted to gas heated in the arc chamber.

Claim 16

An arc heater comprising, in combination, a first pair of axially spaced annular electrodes of a first diameter, a second pair of substantially equally axially spaced annular electrodes of a second diameter greater than said first diameter, the second pair of annular electrodes being coaxially mounted and substantially coplanar with respect to the first pair of electrodes, a third pair of substantially equally axially spaced electrodes of a third diameter greater than said second diameter coaxially mounted with respect to the first and second pairs of electrodes, means enclosing the space between all said electrodes to form a closed arc chamber, said last-named means including means for admitting gas to be heated into the chamber and means for exhausting heated gas from the chamber, the first pair of electrodes being adapted to be connected to terminals of opposite polarity of a source of potential to produce an arc therebetween in a constricted mode of operation, the third pair of electrodes being adapted to be connected to terminals of opposite polarity of a source of potential to produce a constricted arc therebetween, the second pair of electrodes being adapted to be connected to a high current source of potential to produce an arc therebetween, magnetic field producing means so positioned with respect to all the electrodes that when energized a magnetic field is set up extending substantially radially in all directions from the axes of all the electrodes and having a strong magnetic field component transverse to all the arc paths between the first, second and third pairs of electrodes whereby the arcs between the respective pairs of electrodes are caused to move substantially continuously in annular paths around and between the electrodes, the third arc forming a rotary path around the second arc which substantially encloses the second arc and prevents loss of heat from the second arc to the walls of the means forming the arc chamber, the second arc absorbing additional heat by radiation from the first and third arcs whereby the second arc is permitted to go into a diffused mode of operation thereby increasing the enthalpy imparted to gas heated in the arc chamber.