US3290552A - Apparatus for generating high-intensity light with high temperature particulate material - Google Patents

Description

Dec. 6, 1966 D. G. VAN oRNUM 3,290,552 WITH APPARATUS FOR GENERATING HIGH-INTENSITY LIGHT HIGH TEMPERATURE PARTICULATE MATERIAL Original Filed June 14. 1960 PULSE FORMING NETWORK POWDER SOURCE INVENTOR. P DELBERT G. VAN ORNUM ATTORNEY.

United States Patent O APPARATUS FOR GENERATING HIGH-INTEN- SITY LIGHT WITH HIGH TEMPERATURE PAR- TICULATE MATERIAL Delbert G. Van Ornum, Newport Beach, Calif., assignor to Giannini Scientific Corporation, Santa Ana, Calif., a corporation of Delaware Continuation of application Ser. No. 186,587, Mar. 30, 1962, which is a continuation of application Ser. No. 35,940, .Iune 14, 1960. This application Apr. 21, 1964, Ser. No. 363,332

4 Claims. (Cl. 315-111) This invention relates to an apparatus and method for generating an extremely bright light, such light being adapted to be employed in such fields as light radar, cornmunications, search lights, and photochemistry. This is a continuation of my copending patent application Serial No. 186,587, filed March 30, 1962, now abandoned, for Apparatus and Method for Generating High-Intensity Light. Said application is a continuation of application Serial No. 35,940, flied June 14, 1960, for Apparatus and Method for Generating High-Intensity Light, now abandoned.

An object of the invention is to provide an apparatus and method for generating a very high-intensity light, either in brief pulses or continuously, and without effecting clouding of the window in the wall of the chamber in which the light is generated.

These and other objects and advantages of the invention will be more fully set forth in the following specification and claims, considered in connection with the attached drawing to which they relate.

In the drawing:

FIGURE 1 is a schematic view, primarily in longitudinal central section, illustrating the condition of the apparatus during generation of a pulse of light;

FIGURE 2 is a transverse section taken on line 22 of FIGURE 1; and

FIGURE 3 is an enlarged fragmentary section corresponding to the central portion of FIGURE l but illustrating the condition of the apparatus prior to generation of a light pulse.

Referring to the drawing, the apparatus is illustrated to comprise a tube formed of quartz or other lighttransmissive material. Mounted coaxially at the ends of tube 10 are electrode discsv 11 and 12, preferably formed of a metal such as copper, and having openings 13 and 14 formed therein on the axis of the tube. The ends of the tube are illustrated as being inserted in annular grooves in the discs 11 and 12, there being suitable sealing rings 15 and 16 provided to prevent leakage of material from the chamber formed by the tube and by the .electrode discs.

A gas source 18, adapted to deliver an inert gas such as argon at a suitable pressure such as ten p.s.i. gauge, communicates withthe tube 10 through a conduit 19. The inlet from conduit 19 is tangential to the chamber within the tube. The diameter of the inlet opening 20 is so correlated to that of the axial outlet opening 14 that introduction of gas rapidly from source 18 will result in the formation of a gas vortex defining a canal which is indicated at 21 in FIGURE 3. The vorticallyflowing gas, which is indicated at 22, discharges through the opening 14 and (to some extent, during an explosi-on) through opening 13.

Means are provided to introduce a finely-divided powder or particulate substance 23 into the opening 13 for flow through the canal 21 and out the opening 14. Such means is schematically illustrated to comprise a suitable powder source 24 which is connected through a conduit 26 with the opening 13. It is to be understood that a car- ICC rier gas may be provided for the powder, in accordance with principles well known to the art.

The powder is formed of a substance adapted to explode and emit a brilliant light upon sudden passage of a high-current spark or discharge through canal 21, and preferably comprises a metal or compound thereof. Metals such as powdered aluminum and powdered tungsten have been employed with success. Powdered sodium chloride and aluminum oxide have also been found satisfactory.

The light-emitter substance introduced into canal 21 may also be in liquid form. For example, a concentrated aqueous solution of sodium chloride may be introduced through opening 13 in the form of a fine spray.

The particle size of the powder or liquid is caused to be sufliciently small that the particles will remain in canal 21 as shown at 23 in FIGURE 3. When the particle size is sufliciently small, the radially-inwardly directed component of the vortically-flowing gas is greater than the centrifugal forces tending to effect outward movement of the particles.

Means are provided for passing a high-current spark through the canal 21, such means being indicated schematically as comprising a suitable pulse-forming network 27 which is connected respectively through leads 28 and 29 with electrodes 11 and 12. The pulse-forming network may comprise a low-inductance capacitor, or bank thereof, adapted to deliver a high voltage to the electrodes. This results in a high-current spark which'is confined, by the gas 22, to canal 21. The resulting sudden and extreme elevation of the temperature of the powder or liquid may be termed an explosion, and results in generationof a pulse of intense light.

It is a feature of the invention that current flow is terminated substantially before the shock front (indicated at 31 in FIGURE l) created by the explosion reaches the wall of the envelope or window 10. This prevents clouding of the window, as will be described subsequently. The pressure created by the explosion not only results in the formation of the shock front 31, with consequent momentary increase in the size of the canal through the vortically flowing gas, but also results in discharge of jets of plasma 32 and 33 through openings 13 and 14.

Means are provided to reflect the light, after it passes through the window 10, in a desired direction. Such means may comprise a reflector apparatus 35 having a parabolic polished reflector surface 36 the focal axis of which is coincident with the axis of tube 10. It is to be understood that the surface 36 is normally much larger than is indicated in the drawing, so that the light-generating tube 10 and electrodes 11 and 12 only occupy a relatively small region at the axis of the reflector. Reflector apparatus 35 is indicated as having end walls'37 and 38 which may serve as supports for the mounting means (not shown) which maintain the electrodes 11 and 12 in position. The conduit 26 passes through the end wall 37, and a short conduit 39 is provided through the wall 33 so that the discharging plasma will not remain within the reflector. Both conduits 26 and 39 are formed of insulating material.

It is to be understood that a plurality (for example, four) of the devices illustrated in the drawing may be provided dn adjacent relationship and all directed in the salme direction. The pulse-foaming networks 27 for such devices may then all be so correlated or gated that each generates light during one-quarter of a full cycle `of operation, so that a continuous light source is simulated. Each pulse-forming network may tbe Aadapted to deliver a square pulse continuing for one-quarter cycle, with each pulse terminating at approximately the same instant that the pulse for the next light source commences.

Description of the method and summary of operation Stated generally, the method comprises creating a canal by means of vortically-flowing gas, introducing a lightemitter substance into the canal, and passing an electric spark discharge through the canal in order to effect explosion of the light-emitter and consequent generation of intense light.

With particular relation to the apparatus illustrated in the drawing, the method comprises employing the gas source 18 to introduce gas rapidly and tangentially into the cylindrical chamber defined by tube 10, so that the gas flows vertically in `the chamber and results in formation of the canal indicated at `21 in FIGURE 3. Powder source 24 is then employed to introduce powder 23 (or liquid) through opening 13 into the canal 21. This powder remains in the canal 21, being confined thereto by the circulating gas 22 as previously described. The pulse-forming network 27 is then employed t-o impress a high voltage between electrodes 11 and 12, with consequent passage of an electric spark between the electrodes and through the canal 21.

The electric spark effects sudden heating (explosion) of Athe powder 23, with consequent generation not only of an intense light but also of the shock front 31 (FIG- URE 1) which moves radi-ally outwardly toward the wall of the light-transmissive envelope 10. Substanfially before the shock front 31 reaches the envelope wall, current flow is terminated so that cooling of the gas (and dissipation of shock front 31) immediately results. The vortically-flowing .gas then results in re-formati-on of the small-diameter canal 21 (FIGURE 3), and in purging of the chamber of the products of the explosion. The majority of such products discharge through the opening 14 and short conduit 39, but certain of the products pass out through the opening 13 into tube 26. Because of the fact that the chamber is purged of the products of the explosion, .and because of the fact that the shock front 31 dissipates (as stated above) before reaching the interior wall lof the envelope, such wall does not become clouded.

The explosion products which enter tube or conduit 26 (immediately following the explosion) provide a cornpressor or pulsation action, similar to a piston, which has the beneficial effect of agitating the powder within the conduit 26 and aiding in the feeding action.

After the small-diameter canal 21 has been re-established, additional powder 23 is introduced into the canal, and the pulse-forming network `27 is operated to repeat the process. If desired, the flow of powder from source 24 to opening 13 may be stopped and started, in timed relation to the application of voltage pulses, to conserve the supply of powder 23 (or of liquid).

Various embodiments of the present invention, in addition to what has been illustrated and described in detail, may be employed without departing from the scope of the accompanying claims.

I claim:

1. Apparatus for generating high-intensity light, comprising wall means to define a chamber and having a light-transmissi've portion, means to introduce gas continuously into said chamber and to effect vortical flow of gas therein about a central axis and consequent formation of a canal along said axis, means to drain gas continuously from said chamber, means to introduce a particulate light-emitter substance directly into said canal, first and second electrode means disposed at spaced points along said canal, and means to effect passage of an electrical discharge between said electrode means along said canal, said last-named means effecting said electrical discharge at a power level sufficiently high to explode said particulate substance and thus generate high-intensity light.

2. The invention as claimed in claim 1 in which at least part of said wall means Lies in a surface of revolution about said central axis, in which said electrical discharge is a spark discharge, in which said last-named means is adapted to maintain said discharge for an interval of time shorter than the time required for the shock front resulting from said explosion to reach said sur-face of revolution, and in which said light-transmissive portion of said wall means is in said surface of revolution.

3. The invention as claimed in claim 1, in which said means -to introduce said light-emitter substance into said canal comprises a passage formed in one of said electrode means at said axis.

4. A vortex light source, comprising light-transmissive wall means to define a .generally cylindrical chamber, first and second spaced electrodes each having an opening adjacent the axis of said chamber, means to introduce particulate substance through the opening in said first electrode into the axis of said chamber, said particulate substance being adapted when heated to explode and emit intense light, means to introduce gas tangentially into said chamber for vortical flow therein and subsequent draining through the opening in said second electrode, .and means to apply sufiicient voltage to said electrodes to effect generation of a high-current electric discharge therebetween, said discharge passing along the canal in said vortically-flowing gas and having a power level sufficiently great to explode said particulate substance and thereby generate intense light.

References Cited by the Examiner UNITED STATES PATENTS 2,768,279 10/1956 Rava 219-75 2,922,869 1/ 1960 Giannini et al. 219-75 2,929,952 3/ 1960 Giannini et al. 313-231 3,064,153 11/1962 Gage 313--22 OTHER REFERENCES Das Kontinulerliche Spektrum des Kohlelichtbogens, by H. Maeker of Kiel, Zeitschrift fur physik, vol. 144, 1939, pp. 50G-514.

JAMES W. LAWRENCE, Primary Examiner.

GEORGE N. WESTBY, Examiner.

C. R. CAMPBELL, Assistant Examiner.

Claims (1)

1. APPARATUS FOR GENERATING HIGH-INTENSITY LIGHT, COMPRISING WALL MEANS TO DEFINE A CHAMBER AND HAVING A LIGHT-TRANSMISSIVE PORTION, MEANS TO INTRODUCE GAS CONTINUOUSLY INTO SAID CHAMBER AND TO EFFECT VORTICAL FLOW OF GAS THEREIN ABOUT A CENTRAL AXIS AND CONSEQUENT FORMATION OF A CANAL ALONG SAID AXIS, MEANS TO DRAIN GAS CONTINUOUSLY FROM SAID CHAMBER, MEANS TO INTRODUCE A PARTICULATE LIGHT-EMITTER SUBSTANCE DIRECTLY INTO SAID CANAL, FIRST AND SECOND ELECTRODE MEANS DISPOSED AT SPACED POINTS

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