Controlled arc gas heater

Claim 1

An arc gas heater comprising: an injector unit having an enlarged chamber of circular cross section therein and means for injecting primary gas into the chamber at the periphery thereof; a tubular rear electrode attached to the injector unit and projecting rearwardly therefrom with the hollow interior of the electrode opening into the chamber, the diameter of the electrode being substantially less than the diameter of the chamber; a dielectric element located between the rear electrode and the injector unit to electrically isolate the rear electrode for the injector unit; a plurality of interelectrode segments arranged one after the other and projecting forwardly from the injector unit, the interelectrode segments having hollow interiors which define a constrictor passage which communicate with the chamber and axially aligns with the tubular rear electrode, the diameter of the constrictor passage being substantially less than the diameter of the chamber in the injector unit and also substantially less than the length of each interelectrode segment, the diameter of the constrictor passage further being substantially constant throughout its length so that gas will flow through the constrictor passage at a relatively high and substantially constant pressure; a front electrode attached to the forwardmost interelectrode segment and having a hollow interior which aligns with the constrictor passage, the hollow interior of the front electrode being substantially the same diameter as the constrictor passage so as to form a continuation of the constrictor passage; a nozzle located at the forward end of the tubular front electrode and having a throat which is axially aligned with the constrictor passage, the throat having a diameter which is substantially less than that of the constrictor passage so that the gas may accelerate to the sonic velocity within the throat; dielectric discs located between adjacent interelectrode segments and between the rearmost segment and the injector unit and the forwardmost segment and the front electrode so that the interelectrode segments are electrically isolated from one another as well as from the injector unit and the front electrode, means for introducing secondary gas into the constrictor passage from the periphery thereof generally in the regions where adjacent interelectrode segments are contiguous, whereby a potential placed across the two electrodes will cause an arc to extend through the constrictor passage with the termini of the arc being at the electrodes and the arc will transfer energy to the high pressure gas in the constrictor passage, imparting high enthalpy to that gas before it is accelerated to the sonic velocity in the throat.