Патент USA US2403907код для вставки
July 16, 1946. L. A. BuRRows ET AL 2,403,907 ’ SMOKE PO'I..I IGNITER Filed Aug. 12, 1942 7 „vrou/¿s Ajwmldia INVENToRs ' Patented July 16, 1946 2,403,907 UNITED STATES PATENTz OFFICE 2,403,907? SMOKE. POT IGNI'IIER. Lawton A. Burrows, Woodbury, and George A. Noddin, Wenonah, N. J., assignors to E., I'., du Pont de; Nemours & Company, Wilmington, Del., a corporation of Delaware Application August 12, 1942, Serial No. 454,562 3; Claims. (Cl. wilg-704.2.) 1 Z. This invention relates to a novel ignition as sembly, and particularly one adapted for use where the ready ignition, ofl fuel oils or other combustible materials» is desired by remote con particularly on the sides removed from the in itiator- cavity. By this means the name from trol, without the necessity of personalv super vision of each device. Occasions arise frequently Where the. con trolled firing or lighting of' units of combustible materials is tedious and where individual atten tion to each of such units would :be too time consuming or would require an excessive amountl of labor. Orchard heaters, for example, are used for the protection of fruit trees against frost, and delay in the lighting of a large number of such heaters may be serious because of the wastey of fuel in the case of those ñrst: lighted, or- undue exposure to cold in the case of trees last pro the deflagrating: charge, upon initiation, will be directed out on the side adjacent to the initiator . cavity toward? the material to be ignited. Pref erabl'yÍ the main deflagrating charge will com prise black powder in block or pellet form, and> we desirably enclose this in a Wrapping of a flexible metal. The apparatus: of our invention may be under stood more clearly byy reference to the accom panyingV drawing; in which one embodiment is shownfby way- of illustration. Figure l is an elevation of" a black powder pellet adapted to .serve as> the main deñagrating charge. Figure 2 is a cross-sectional View of an electric squib, suitable for use in initiating the combustion. Figure. 3‘ isî a vertical elevation cut-away of the tected. Similar problems' may be met. in the ignition assembly according,Y to the invention. lighting of Warning lights; in road construction or repair work, in the ignition of smoke pots for 20 Referring in more detail to`r the drawing, l in Fig. 1 showsV a. substantially cylindrical black obscuring purposes, in the instantaneous light powder pellet having Within it a cavity 2. A ing of a large number of signals, and in other convenient size for such pellet is a length of fields. 2 inches and a diameter- of approximately 11/¿1 Electric ignition would be a desirable solution to the above problem, but diliiculties. are metl In Fig. 2, an electric squib or igniter is shown when it` is desiredA to ignite, electrically a. large of a4 type suitable for use in bringing about the number of bodies of diflicnltly-ignitible heavy deflagration of' the black-'powder pellet. The oil for example. It necessary that. ignition metal shell' 3, for example of a copper alloy, be assured, regardless of weatlfierI conditions, ïhavingr a. length of 1% inches and a diameter wind, precipitation, andl the like. commercially of about. 1A. inch, containsv av 5-grain base` charge available electric squibs are not suitable: because 4 of` a. mixture adapted tov give a very high tem of the short duration of the flame, and it. is es perature onr ignition, for example 87.5' parts of sential; that a considerable source of; heat- be barium peroxidev and 12.5l parts of ñnely divided appliedv for an appreciable time interval.: at the spot, Where ignition is to take place. No prac 35: magnesium. On this base charge is a super posed ignition charge of 10 grains of a- blend of tical assembly or device is: now available for ac 83.3 parts of barium peroxide, 14.7 parts of complishing the foregoing purposes. selenium, and 21 parts of' powdered aluminum. An object of the present invention is an. ig The.V leg or leading Wiresl ‘l from the electric nition assembly- suitable; for use Where diilicultly ignitible materials are present. A further object 4(1): ‘ig-niterf aret held iirmly in a predetermined posi tion by passage through a plug 8k of tightly lit is such an assembly adapted to bring about the tingv material; such as a sulfur composition or> substantially simultaneous; ignition or a. number rubber, the ends of the wires being connected of bodies of such materials without the necessity by` a smaller diameter wire of high resistance 9. ‘ of attention to the individual. operation. AA still further object is such an assembly- su-ñiciently 45'. This fine Wire is surrounded by a Ibead of' com bustiblefmaterial> Gf adapted to yield a hot llame ` protected from the influence of weather and on ignition; The firing of this bead is brought Water to assurel its proper functioning. Addi about by> the passage of an electric vcurrenttional objects will be disclosed, as the invention through the Wires 1f, which causes the heating is described more at length hereinafter. of the bridge wire: 9i to incandescence and' the We have foundl that the foregoing objects consequent inflammation of the. bead material. are attained when We employ an» ignition as This, in turn, initiates the charge 5 and brings _ sembly comprising a main charge of a deflagrat about the ignition of the base charge 4. ing explosive having a. cavity therein,l an` elec Fig. 3 shows an assembly of elements that act tric initiator within this cavity, and confining means about the charge of deñagrating explosive,~ 65 in. conjunction with one another» to; produce the. inches. y y 2,403,907 3 4 desired results. The black powder pellet I has but it is essential that the squib charge employed a cavi-ty 2 into which the electric squib 3 is in serted. The leg wires 'I are shown emerging from be suñîcient to bring about the sure ignition of the main charge. We find it desirable to use the squib and pass up on opposite sides of the in the sc_luib` a composition including an oxidizing agent and a finely divided metal characterized by having a, high heat of combustion. The use pellet, being joined above in a twisted relation ship. These wires serve to support the pellet and of blends of barium peroxide and finely divided magnesium metal answers this requirement sat isfactorily. The exact type of igniter or the com powder pellet is tightly enclosed within a sub stantially cylindrical container of a flexible metal 10 positions included are not essentials of the in vention. While we have shown a type in which I0, for example a lead alloy containing a low initiation is effected by means of an inflammable percentage of antimony. This container tube bead, the concave plug type of initiator may be may be made by any desired method, such as ex used equally well, that is to say one in which trusion, and the method of preparation is no part the plug has a concave cavity at its lower end of the invention. This flexible metal tube com in which an ignition composition is enclosed and prises at its bottom a circular piece of a similar brought to ignition by the bridge wire. metal, for purposes of support, having a water Our preferred form of assembly encloses the tight well 2 of like metal extending upward in main explosive charge in a cylindrical sheath of the center into the cavity in the pellet. This well serves to contain the electric igniter. The 20 metal. This is desirable because of the Water prooñng effect imparted.. The metal tube is not entire metal cylinder is desirably closed at the top by having the edges folded over and crimped, essential, however, and the black powder pellet as shown at I2, so that a waterproof container or other explosive may, if desired, be enclosed in a paper receptacle of suitable weight and water for the black powder charge is provided. The rigidness of the assembly is promoted also, and 25 resistance, for example a spirally wrapped con more particularly continued support of the ignit tainer arrangement. In such event, the bottom and top of the pellet may be protected .by closures er when Ithe wires have burned through below, by securing the leading wires of the igniter to in the form of what has been designated as “shot the sides of the assembly, for example by small gun crimps," where a heavy paper or cardboard pieces of adhesive tape near the top of the metal 30 disc is inserted at each end of the wrapped pellet tube on both sides, as shown at I3. Since it is and the side paper is rolled'down at the ends to meet the disc and to give a waterproof package. desired that the flame be directed downward, or at least in the direction toward which the igniter Such a package may be further protected, if de cavity is facing, downward direction of the flame sired, by dipping in paraffin, or the pellet itself is assured by introducing a body of solid material 85 may be given a parafñn coating. at the top of ,the black powder pellet, as shown The preferred embodimentl of our invention at I4. A suitable material has been found to be given in the drawing has shown a prepared elec cast sulfur, poured onto the pellet in molten state tric squib inserted in the internal well of the metal and allowed to solidify there. In addition to the tube, the squib being adapted to fire the pellet metal container, the black powder pellet will de 40 of black powder through the metal wall of the sirably be enclosed in a paper package. well. We may, however, dispense with the Ysepa While the assembly described may be used for rate squib and load the igniting charge directly the ignition of any desired material, we find it into the cylindrical cavity formed by the well particularly effective in the case of diflicultly walls. In such case the ignition may desirably be combustible materials, such as heavy fuel oils of the concave-plug type, where the leading wires which might be used in smoke pots where ob pass through the plug and the concave end of the scuring smokes are desired; in smudge pots such plug toward the black powder is ñlled with the as are employed in fruit orchards where the heat ignition charge. The bridge wire passes through ing effect of the smoke and gases is desired; and the ignition charge. In an igniter for such an in other like instances. The assembly is excel 50 assembly, the concavity would be suiiicient to hold lently adapted for use with fuel oils, since it can a charge sufficiently large to ñre the deilagrating be suspended at the desired height above the oil, explosive. ' and an intense hot iiame from the black powder We have described our ignition assembly at ‘ pellet is directed downward onto the oil for a length in the foregoing. It should be under considerable period of time, sufficient to assure 55 stood, however, that many variations may be in permanent ignition. troduced in the exact procedure followed or in In the specific embodiment shown in the draw- . the diiîerent materials and compositions used, ing, a block or pellet of black powder was desig without departure from the spirit of the inven assembly in the desired position, with the igniter entering the pellet cavity from below. The black nated as the main explosive charge for the as sembly. We may use other deilagrating explo sives, however, for example suitably shaped blocks tion. We intend to be limited, therefore, only by 60 the following patent claims. We claim: y _ of smokeless powder or other readily ignitible 1. An electric ignition assembly comprising a compositions giving a long durable flame. It is main charge of black powder in the form of a essential that the deñagrating explosive be in cohesive block, a cavity within said block, a thin such form that a cavity is available for the elec 65 metal sheath surrounding said black powder tric sduib. No speciñc composition of black pow charge and in water-tight relationship therewith, der is required, but we find satisfactory the ordi said metal sheath being provided with an internal nary blends of sodium nitrate, charcoal, and sul well projecting into the cavity in the explosive, fur, with possible small additions of other ingre an electric initiator within said internal well, and dients. The black powder pellet, previous to en 70 a reinforcing additional body of solid material at closure in the metal tube, will ordinarily be the side of the black powder charge oppositeto wrapped in heavy paper, with igniter hole ex that through which the cavity enters, whereby posed. upon initiation the direction of the flame from Various types of electric squibs may be em the black powder toward the side adjacentA to the ployed as igniters for the deñagrating explosive, 75 internal cavity is favored. ' ' 2,403,907 5 2. An electric ignition assembly for igniting liquid fuel and other combustible materials, com prising a charge of black powder in the form of a cohesive block, a cavity within said, block, a thin layer of metal around said black powder charge and in water-tight relationship therewith, said metal layer extending also in the form of an in ternal well into the cavity in the black powder, an electric initiator within said internal well, the assembly being so supported that the opening of the internal well is on the under side, the leading wires of the electric initiator passing up along the sides of the block of black powder so as to 6 3. An electric ignition assembly comprising a main charge of a deñagrating explosive in the form of a cohesive block, a cavity within said block, a thin metal sheath surrounding said charge and in water-tight relationship therewith, said metal sheath being provided with an internal well projecting into the cavity in theexplosive, an electric initiator within said internal well, and a reinforcing additional body of solid material on 10 the side of the explosive charge opposite to that through which the cavity enters, whereby upon initiation the direction of the flame from the ex plosive toward the side adjacent tothe internal ' ` cavity is favored. suspend the assembly in the desired position, and a body of solid material at the top of said black 1li powder charge adapted to direct the flame down ward. LAWTON A. BURROWS. GEORGE A. NODDIN.