US 2783684 A
Description (OCR text may contain errors)
METHOD AND ll/IEAlli PROPAGATING A Yusuf A. Yoler, Schenectady, N. Y., assigner to General Electric Company, a corporation of New York Application March 1, 1956, senat No. 570,001
Claims. (cl. 89-7) This invention generally relates to improvements in the method and means for generating and applying energy, and more lparticularly to improvements in the method and apparatus for propagating a mass down the length of an enclosure at great speed.
The generation of strong shock waves within shock tubes and the ring of projectiles out of guns are customarily performed by suddenly releasing energy to generate an expanding mass of gas or vapor Ibehind a projectile or shock wave. Otherwise stated, this generation of force and power is initiated by Va single sudden release of energy, by Vsuch means as an explosion or the like, resulting in the rapid expansion of the gas behind the projectile or behind the shock wave. However, with this technique, which may be termed a single shot of energy release, the pressure 4and `temperature of the gas initially builds up to a high value and then decays at a rapid rate asthe projectile or 'shock wave travels down the length of an enclosure; and, consequently, the maximum speed of propagating the projectile or the shock wave is 'lower than could be obtained if the pressure and temperature could be maintained at a high level behind the projectile or shockwave.
In accordance with the present invention, a unique method and apparatus have been Vevolved for maintaining such a high pressure and temperature level continuously behind the projectile or shock wave as it passes down the length of an enclosure. This is performed by a continual and successive multiple discharge of energy into the enclosure in a controllable manner and in a proper sequence behind the projectile or wave to maintain a nearly uniform high energy level in the expanding gas. By maintaining this high level of energy, rather than employing a single release of energy whose level decays at a rapid rate, it is evident that the projectile is maintained at a uniformly high acceleration and progressively increases speed as it travels down the length of the tube at a considerably greater rate than possible with a single energy release of the same magnitude.
It is accordingly one object of the present invention to provide an improved method and apparatus for propagating a shock wave or for propelling a projectile at greater speeds than heretofore attainable.
A second object of the invention is to provide an improved method and apparatus for successively releasing energy in a spaced manner within an enclosure forvmaintaining controllable and distributed energy level or accelerating force along `the length of the enclosure.
Another object of the present `invention is `to provide a more ecient method and apparatus for applying electrical energy to accelerate `a mass.
Still a further object of the present invention is to provide a less expensive and simpler method and apparatu for accelerating masses.
Other objects and many attendant advantages of this invention will be more readily comprehended to those skilled in this art upon a detailed consideration of the States Patent r"ice following specification taken with the accompanying drawings wherein:
Fig. l is a diagrammatic sketch depicting one preferred manner of automatically releasing electrical energy in sequence down the length of an enclosure in accordance with one preferred process of the present invention, and
Fig. 2 is a View similar to Fig. 1 illustrating one preferred apparatus for performing the technique of Fig. l.
Referring now to Fig. 1 for a consideration of one preferred method and apparatus in accordance with the present invention, there is shown, in section, an elongate tube 10 that is sealed at the left-hand portion and open ended at the right, and preferably formed of electrically nonconducting material in a cylindrical shape as shown. A series of spaced conducting electrodes 12-18, inclusive, that are electrically insulated from one another, are distributed along the length of the tube. An additional starter electrode 1 1 is positioned at the sealed left-hand portion of the tube, as shown. `l'inergizing each adjoining pair of these electrodes 11-18, inclusive, is a separate high voltage source of electrical energy 19-25 inclusive, with each source having its terminals energizing adjacent electrodes through a suitable electrical network `for controlling the time constant of any electrical arc that may discharge through that electrode.
The starting direct current source 19 energizing the end electrode 11 and the first electrode 12 through a normally open switch 34, is of a large venough direct current voltage to initiate an arc discharge through the gas, such as air, within the tube when the switch 34 is closed. However, the potentials across the remaining electrodes 12-18, inclusive, are not suiciently large for generating an arc through the gas within the tube.
To initiate the operation, switch 34 is closed connecting source 19 across end electrode l11 and first electrode 12. This high voltage generates an arc within the tube, in the pattern generally represented by the line 35; imparting or dumping great heat and electrical energy into the tube and generating a great expansion of gases which form a shock wave. Concurrently the electrical energy poured into the tube and the rapid heating of the vapor causes the gas to ionize.
As the shock wave is accelerated down the length of the tube, this ionized gas behind it travels between the tirst pair of electrodes 12 and 13 lowering the electrical resistance of the gas between electrodes 12 and 13 and enabling an arc to be generated across these electrodes as generally represented by the lines 36. This arc feeds an additional jolt of electrical energy into the tube at a position spaced from the first electrical discharge. The time constants of each arc discharge and the electrical energy imparted by the arcs are controlled to maintain the energy level constant as the shock wave travels down the length of the tube, thereby continually renewing the energy level in the tube immediately behind the shock wave and preventing any `decay in this energy level such as would normally result from a single shot discharge.
Thereafter, as the shock wave travels past each pair of the electrodes, the ionized gas continually moving behind comes in contact with'each successive pair of electrodes thereby continually imparting jolts of energy into this tube in such amanner as x12o-maintain the energy content ata uniformly 'high lpredetermined level and `obtain Within the tube to provide this force.
the desired great speed of propagation of this shock wave down the tube. This permits the addition of energy in a continual and successive manner into the tube enabling a much greater energytobe generated within the tube at spaced intervals along the tube thanY could be possibly obtained with the. single shot method and .apparatus employing a tube of comparabledimensions.
The time constants of the successive discharge paths are so adjusted that the rst discharge'is preferably. the longest and each succeeding discharge continues to supply current until the work of the shock wave is completed.
In the event it is desired to employ this unique process for propelling a projectile at high speeds down the length of this tube, the projectile 42 is preferably mounted upon a suitable shoe or piston-like device 43, as shown in Fig. 2. In this case, each successive arc between the electrodes maintains the high pressure and temperature of the expanding gases behind the projectile at a desired high level as the projectile is propagated down the length of the tube. Maintaining this temperature and pressure at this high level, maintains the force accelerating this vprojectile down the length of the tube at a desired high level and, t erefore, propels this projectile at relatively high acceleration throughout its travel in the gun. Consequently, being driven at a relatively high acceleration, the velocity with which this projectile travels progressively increases as it passes down the length of the tube, and the muzzle velocity or speed of projectile ejection from the end of the tube is a function of the length of the tube and the maximum energy that can be generated This operation is to be contrasted with the conventional single shot tiring of projectiles, since in the single shot or conventional methods the energy forcing the projectile out of the tube ldecays as a function of this length. In accordance with the present invention, on the other hand, the force propelling the projectile down the tube is maintained at a high level and .the projectile is, therefore, maintained at a high acceleration whereby its velocity increases at a considerably greater rate than in prior devices.
As shown by one preferred structure in Fig. 2, the enclosure it! may be preferably formed of a single elongate tube 50 or of a series of separate cylindrical insulating sections 50 connected in sequence by conducting ring-like electrodes 51 having a substantially T-shaped cross section. The sealing means at the lefthand end of the tube 50 may be the starting conducting electrode 52 which is suitably joined to the rst nonconducting cylindrical section or tube to provide a iluidtight seal. It is evident that the thickness and strength of the cylindrical tube 50 or the thickness and strength of the individual sections 50 and connections to the conducting rings holding these sections together must be so designed as to withstand the extreme internal temperatures and pressures generated for propagating the shock wave or the projectile 42.
Rather than employing separate direct current voltage sources to energize adjoining ring like electrodes, as shown in Fig. l, it is preferred to employ a series of capacitors 53-59, inclusive adapted to be charged by a single high voltage direct current source 60 through suitably selected charging resistors 61-67, inclusive, whose values are adjusted to provide the desired time constants. The discharging of these capacitors through inductors 26-32, inclusive, as discussed above control the time constant of the electrical energy passing into the tube as arcs are successively generated between adjoining electrodes.
if this preferred method is employed in a gun to propel a projectile 42, the projectile structure, as shown, is preferably formed of the projectile itself 42 suitably ,mounted upon a sabot or shoe 43 in the form of a cup shaped piston, as shown. This enables the pressure VWithin the tube to exert the maximum force against the projectile shoe. I f desired, the projectile 42 and shoe 43 may be disengageably connected so that the projectile is separated from the shoe upon leaving the tube enabling the shoe to fall away and .the projectile to be directed along a ballistic trajectory at the desired high speed.
Thus by means of the present invention, it is observed that there is provided a more efcient means for imparting great amounts of energy within a closed container than could heretofore be obtained by employing the single shot of energy techniques. This is accomplished by successively generating energy in a spaced manner along the Length of an enclosure whereby as the shock wave or propelled element travels down the length of this enclosure, the forces propagating Ithis wave or projectile do not decay but are continually maintained at high pressure-temperature conditions throughout the length of the tube.
lt is believed well known to those skilled in the art that this electrical a-rc discharge technique provides a much greater propagating speed than does the Vusual chemical reactions, since greater temperatures, more uniform heating and greater control of the release of energy are obtained within the tube than can be obtained with the usual chemical reactions. t is further evident to those skilled in the art that this means for generating and applying greater usable energy can be obtained automatically or in a self-triggering manner that is quite simple and inexpensive since the propagated element or shock wave, itself, triggers or switches the various energy gene-rating means -to impart energy to the tube in a desired sequence thereby requiring no additional switching or timing mechanism. Additionally, if desired, more elaborate external circuitry may be employed to trigger the arc discharges in a different sequence or to provide greater control of the time constants.
Although but one preferred method and apparatus have been disclosed and illustrated as required by the .Patent Laws it is believed evident to those skilled in the art that many changes may be made in the shape and structure of the cylindrical tubes, ring electrodes, capacitor charging and discharging elements, or any of the other preferred details shown and described above without departing from the spirit and scope of this invention. Additionally it is believed evident that means other than the generation of an initial electrical arc may be used lto initiate operation since the exhaust gases from chemically generated explosion could likewise be used to trigger the succession of arcs along the container. Consequently it is intended that this invention is to be limited only in accordance with the following claims appended hereto.
What is claimed is:
l. The method of sequentially generating energy to propagate a shock wave or propel a projectile down the length of an elongate enclosure containing a gas comprising the steps of: generating a first discharge at one end of the enclosure to greatly heat and ionize this gas setting it in motion down the length of the enclosure, and utilizing the movement of this ionized gas to sequentially trigger a successive series of electrical arcs spaced from each other in time and position down the length of said 'en-closure, said ionized gas being employed to lower the electric resistance of the gas as it travels down the length of the enclosure thereby enabling the sequential initiation of said electrical arc discharges.
2. The method of propagating a shock wave or propelling a projectile down the length of an elongate nonconducting container enclosing a substantially non-conducting gas comprising the steps of: energizing spaced portions of said container with voltage potentials of insuflicient magnitude to generate an electric are through the gas in its un-ionized state, releasing energy at one end of said container togreatly heat and ionize the gas placing it in motion in a wave traveling down the length of the container, said movingionized gas initiating a sequential series of electrical arcs as said ionized gas passes :each ofsaid spaced portions, whereby the electric energy .lijk lay..
being generated within said gas and behind said moving wave is maintained at a substantially high level.
3. The method of propagating a shock wave or propelling a projectile down the length of an elongate nonconducting container enclosing a substantially non-conducting gas comprising the steps of: applying voltage potentials along adjoining portions of said container having insufficient magnitude to generate an electric arc through the enclosed gas, generating a first energy discharge at one end of said container to greatly heat and ionize the gas placing it in motion in a wave traveling down the length of the container, said moving ionized gas initiating a sequential series of arcs as said ionized gas passes each of said spaced adjoining portions, whereby the electric energy being generated within said gas and behind said moving wave is maintained at a desired high level.
4. The method of generating a shock wave traveling at extremely high speed down the length of a non-conducting container housing a substantially nonconduct ing gas comprising the steps of: producing a series of spaced electrical fields within said gas in a direction along the length of said container whose eld strength is just insuthcient to initiate ionization and arcing through said gas, producing a rst energy discharge at one end of the container to greatly heat and ionize the gas thereafter initiating a shock wave down the length of said container and setting the ionized gas in motion behind the shock wave, whereby as said ionized gas sequentially moves through each of said electrical fields, it initiates a successive series of arc discharges through the gas continually renewing the energy behind said shock wave to maintain a high energy level propagating said wave throughout the length of the container.
5. The method of propelling a projectile at progressively increasing speed down the length of an elongate housing of electrically insulating material containing said projectile and air comprising the steps of: applying large direct current potentials at spaced portions along said housing to produce a series of electrical fields within said gas along the length of the housing producing an initial energy discharge `within said housing behind said pro jectile to greatly heat, expand, and ionize the air thereby propelling said projectile down the length of the conrainer and permitting said ionized air to `expand and travel behind the projectile, said expanding ionized air operating to trigger each of said applied potentials in sequence, to produce an automatic succession of electrical arcs within said housing as the projectile passes each of said spaced portions.
6. In an apparatus for generating enengy to propel a shock wave or projectile down the length of an elongate t container housing a gas, an elongate non-conducting container having one end thereof sealed and the other end open to air, a series of conducting electrodes positioned in a spaced manner within said container, means for applying direct current potentials to said electrodes to produce spaced electrical ields within said container, and means for generating an energy discharge in the vicinity ot the sealed end of the container to greatly heat, expand and ionize the air and set this air in motion down the length of the container, whereby as said ionized air passes said spaced electrodes, it triggers a sequential series of electrical arc discharges within the container.
7. In an apparatus for sequentially generating energy to propagate a shock wave or propel a projectile, an elongate non-conducting hollow tubular member having one end thereof sealed and the other end open to air, a series of conducting electrodes positioned within said member and spaced along the length of said member, means for applying direct current potentials across each adjoining pair of electrodes to produce spaced electrical elds within said member of insufcient magnitude to ionize the air, and means for producing a iirst electrical arc discharge within said member and in the vicinity of the sealed end of the member to greatly heat and ionize the air and set this ionized air in motion down the length of the member, whereby as said ionized air passes each of said spaced electrical lields, it lowers the electrical resistance of the gap between said electrodes and triggers the generation of an electrical arc therebetween, thereby enabling the successive generation of electrical arcs down the length of the member maintaining the energy level behind the traveling ionized gas at a high level.
8. in the apparatus of claim 7, a plurality of electrical reactance networks, each in circuit with the means for applying direct current potentials to adjoining pairs of electrodes, and each network adapted to control the magnitude and time phase generation of current through these electrodes forming the arc discharge.
9. In an apparatus for sequentially generating energy to propel a shock wave or a projectile, an elongate nonconducting tubular member having one end thereof sealed and the other end open to air, a series of conducting rings within said member and spaced from one another, means for applying direct current potentials to energize each adjoining pair of rings thereby to produce a series of spaced electrical fields Within said member, and means for ionizing the air within said member in the vicinity of the sealed end thereof and setting said ionized air in motion down the length of the member, whereby as .said ionized air traverses each pair of said spaced rings it triggers an electric arc discharge thereacross, enabling the generation of a successive series of electrical arc discharges down the length of said member.`
l0. In the apparatus of claim 9,-'a plurality of electrical reactance networks, a different one of said networks being in circuit with each of said pairs of ring electrodes, and each of said networks adapted to control the magnitude and time phase of electrical currents passing through said ring electrodes during the arc discharge thereacross.
No references cited.