# United States patent RE4816

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UNITED STATES PATENT OFFICE.
ALFRED NOBEL, OF HAMBURG, GERMANY, ASSIGNOR TO THE UNITED STATES BLASTING-OIL COMPANY, OF NEW YORK, N. Y.
IMPROVEMENT IN EXPLODING NITRO-GLYCERINE.
Specification forming part of Letters Patent No. 50,617, dated October 24, 1865; reissue No. 3,378, dated April 13, 1869; reissue No. 4,816, dated March 19, 1872.
DIVISION B.
To all whom it may concern:
Be it known that Alfred Nobel, of the city of Hamburg, Germany, has invented cer­tain new and useful Improvements in the Manu­facture of Nitro-Glycerine and certain com­pounds thereof, and in the utilization as ex­plosives of the same and analogous substan­ces, known as nitrates of ethyl and of methyl and nitro-manite.
The improvement in the manufacture of nitro-glycerine is the subject of a separate specification; this specification having refer­ence to certain modes of utilizing, as explo­sives, nitro-glycerine and the analogous sub­stances above mentioned.
There is a class of explosives long known, but not at, the date of Nobel's invention ap­plied to technical purposes, in consequence of practical difficulties in procuring their explo­sion. Such substances are nitro-glycerine, the nitrates of ethyl and of methyl and nitro­manite. These substances are liquids at or­dinary temperatures, and by that characteristic are distinguishable from solid explosives, such as gunpowder, gun-cotton, &c.; and they have also the property that fire may be applied to them without exploding. Nitro-glycerine, for example, if ignited in an open space, is slowly decomposed and takes fire, but the flame is apt to die out when the match is withdrawn; hence it cannot, under ordinary circurmstances, be looked upon as a ready explosive agent; for while gunpowder, and other substances used as explosives prior to Nobel's invention, al­ways explode or deflagrate throughout the whole mass when fire is set to them, nitro­glycerine and the analogous substances before named will not explode from the mere contact of flame. So, also, if a drop of nitro-glycerine be poured on an anvil, the blow of a hammer causes it to explode, but only that part is in­volved which has received the blow, so that in this case the explosion is merely a local one.
A principal object of Nobel's invention consists in the removal of this obstacle to the use of nitro-glycerine and the analogous substances before named as explosives. For this end, two different methods welt invented by Nobel for promoting the expulsion of nitro-glycer­ine ; one method, which forms the subject of a separate specification, relates to the combina­tion with nitro-glycerine of other more easily explosive substances; and the other method, which is the subject of this patent, relates to the means of effecting the explosion without such combination. This is accomplished either by procuring an initial explosion of a minute por­tion of the whole charge of nitro-glycerine, which then, by means of the heat and pressure of the gas thus developed, involves the whole mass in explosive decomposition, or by creat­ing an impulse of explosion by means of conssive agitation; the means employed in both cases being in such relation to the mass of nitro-glycerine to be exploded as that the lat­ter shall be confined within the influence of such initial explosion or impulse of explosion. The pressure being developed by the heating to the point of explosion of a minute portion of the charge, nitro-glycerine is made use of in the one instance; and in the other the de­tonation of some violently exploding substance in presence of the charge of nitro-glycerine.
Nitro-glycerine as well as the analogous ex­plosives hereinbefore named being liquid, if in such condition that it cannot escape from the infuence of the initial explosion, (as, for instance, when placed in a bore-hole for blasting,) receives and propagates the initial press­ure through its whole mass, and the first impulse of explosion is communicated through­out the whole charge, effecting its instantaneous decomposition and explosion. By the term impulse of explosion is meant motiou produced to effect the explosion by suddenly communicated force.
There are many means of obtaining this im­pulse of explosion—such as, first, by placing the nitro-glycerine to be exploded in a tube or case of any suitable material which will hold it, and surrounding this tube with gunpowder, gun-cotton, or any-readily exploding substance, which, being easily fired by any of the well­known means, will instantaneously cause the explosion of the nitro-glycerine in the tube; or, by reversing this process and pouring the nitro-glycerine into the bore-hole (for blasting) and inserting into the nitro-glycerine a tube charged with gunpowder or gun-cotton, or oth­er easily exploding substance, when, by firing the charge in the tube, the nitro-glycerine is also exploded.
When used for the purposes of blasting, the nitro-glycerine may be poured directly into the bore-hole, which may be closed above to pre­vent the scattering or blowing out of the charge; for which purpose loose sand will do, or the upper part of the bore may be left en­tirely open. lf not convenient to pour the nitro­glyerine directly into the bore-hole, it may be placed in cases of paper or metal, or other suitable material, open or closed at top, as may be preferred.
Second. By the use of what Nobel calls to "igniters" or "burners," being a small tube of glass, paper, or, other material, filled or charged with gunpowder or other easy explosive, and furnished with a fuse or other means of ignit­ing the same by fire or by an electric spark. The burner may be introduced into the nitro-glycer- ine and being fired in any convenient manner, its explosion gives to the nitro-glycerine the requisite impulse of explosion. These igniters may be greatly varied in construction, but in their simplest form they consist of a wooden cylinder hollow inside and filed with gunpow­der, being corked at the one end and connected with a fuse at the other. When the nitro-glycerine has been poured into the bore or blast-hole, this cylinder is let down by its fuse until it swims in the nitro-glycerine, and then, if de­sired, the upper part of the bore is filled with loose sand, and nothing remains but to ignite the fuse. The fuse in, its turn fires the explo­sive contained in the wooden cylinder, the hot gases of which rush into the charge of nitro­glycerine and the whole mass immediately ex­plodes.
In the drawing, Figure 1 illustrates one of these igniters, in which a is the wooden cyl­inder e, the cavity, filled with gunpowder and closed by the cork or plug f; and g, the fuse. The nitro-glycerine in the bore-hole is repre­sented at c.
Third. A third method is to heat a minute portion of the charge of nitro-glycerine to its point of explosion by inclosing a minute por­tion, of nitro-glycerine in a tube filled either with rocket-powder, (which, being easily ig­nited, is fired in any convenient way,) or with lime and water, or some other chemical agents adapted to combine gradually, and by their reaction create the necessary heat. The explosion, in the tube will give to it the impulse required to explode the mass of nitro-glycerine.
Fourth. A fourth mode of producing the initial explosion is by means of a spark, or by heat developed by a powerful current of elec­tricity within the charge of nitro-glycerine, which is so inclosed as not to afford an escape to the gas developed thereby. Figs. 2 and 3 illustrate the apparatus for thus effecting the explosion. h is the case for holding the charge of nitro-glycerine, which may be closed at top or not, as may be preferred. i i are two wires, which pass rough glass tubes k k, or other insulating substances in the plug or cap of the case, the wires being immersed in the nitro-­glycerine, and their lower ends connected by a fine platina wire, z. The wire z being heated by the passage of the electric current, the liquid in contact with the wire is decomposed, giving the initial explosion, and the heat and pressure developed thereby instantaneously decompose and explode the contents of the case.
Fifth, still another method is by means of a capsule, more commonly termed in military art a percussion-cap, which, being exploded in any convenient manner, gives, by its detona­tion, the requisite impulse to explode the charge of nitro-glycerine.
Sixth, the necessary initial explosion may also be effected by means of an ordinary blast­ing-fuse. This will do in a closed space and under sufficient resistance; but, if the gases of the portion of the nitro-glycerine decom­posed by the heat of the fuse are enabled to escape before they accumulate to such a press­ure as to effect the requisite impulse of explo­sion, the vitro-glycerine is slowly decomposed and the fire generally goes out before the whole is consumed. The explosion if produced by a fuse under the condition of the confinement of the nitro-glycerine is effected by the initial decomposition of a minute portion of nitro­glycerine.
In speaking of nitro-glycerine in the fore­going specification and in the following claims, the nitrates of ethyl and methyl and nitro­manite (being fluid explosives analogous in character and composition to nitro-glycerine) are intended to be included as if specially mentioned.
In view of the fact that the explosive substances hereinbefore named, which are liquid at the ordinary temperature, had not at the date of Nobel's invention been applied to any technical use as explosives, and that by his invention he introduced these substances from the domain of science into that of practical use in the arts— What we claim as the invention of said Alfred Nobel, and desire to secure by Letters Patent in the name of The United States Blasting-Oil Company, as assignee of said Nobel, is—­
1. A charge of gunpowder, gun-cotton, or other easily-igniting and exploding substance, surrounding a tube or case containing the charge of nitro-glycerine, as a means of exploding the same, substantially as hereinbe­fore described.
A charge of gunpowder, gun-cotton, or other easily-igniting and exploding substance surrounded by a nitro-glycerine charge, and combined therewith as a means of exploding, the same, substantially as and for the purpose hereinbefore described.
3. A nitro-glycerine igniter or exploder, con- sisting of a tube or case inclosing a minute portion of nitro-glycerine, together with lime and water, or other equivalent substances, which by combining will evolve the requisite heat to explode the nitro-glycerine therein, sub­stantially as and for the purposes hereinbefore described.
4. An igniter or exploder, consisting of a tube or case containing rocket-powder mixed with a minute portion of nitro-glycerine, and furnished with a fuse or other means of setting fire to the igniting charge, substantially as hereinbefore described.
5. An electric spark, or heat generated by electricity within the charge of nitro-glycerine, as a means of promoting an impulse of explo­sion therein, substantially as hereinbefore de­scribed.
6. A capsule or percussion-cap, furnished with a suitable means of firing or exploding the same, and suitably arranged in relation to the nitro-glycerine so as by its detonation to im­part the necessary impulse of explosion there­to, substantially as herein before described.
7. An igniter for producing the explosion of nitro-glycerine, consisting of a case of wood or other suitable material for holding the ini­tial explosion-charge, closed with a cork or plug, and a fuse or other means of ignition substantially as hereinbefore described.
In witness whereof the said The United States Blasting-Oil Company, by Tay P. Shaffner, President, have hereunto set their hand.
Witnesses:
       Octavius Knight,
       Edmd. F. Brown.