US2235298A - Manufacture of smokeless powder - Google Patents

Description

"55 understood, however,

Patented Mar. 18, 1941 I MANUFACTURE or SMOKELESS rowmas,

.rmrm 'oise nnsn, 111., asslgnor to Western Cartridge Company, East Alton, Ill.,' a corpora- 1 tion of Delaware No Drawing. Application June 10, 1935,

= Serial No. 25,810

Thisg invention, relates generally to the manufactureof explosives and particularly to the man- I ufacture or smokeless powders As to common subject matter this application is a continuation 5 otthe lpriorcopending applicaion of Fredrich Olsenetal Serial No. 629,302, filed June so, 1932, aswellasfipplication of Fredrich Olsen, Serial No. 753,503, filed November 17, 1934. It isl among the objects of this invention-to 10 provide 'aprocess whereby deteriorated and par.-

tially' unstable powder may .be' so treated and renovatedz as to render it adaptable for use in ammunition, A more specific object of the present invention is to provide a process of making l m smokeless powders suitable for use in small arms ammunition wherein deteriorated cannon powder having unstable regions may be employed as "the raw-material.

Another object is to providc-a-process whereby is sateand economicalg 1'5 her? bjectiis to provide a process for makeless powder wherein the resulting grains Twill unifo I fbustion I iii -Zt'oanother phase of the invention, I ,7 geneijally stated, is to provide a process oft iialon propellant powder in which fine parti- =15"ofesi'riokelessslpowder are agglomerated tos s ers iszaiplasti'cizer for nitrocellulose. 2

.Ano't 'ji'flob fii t Of this invention isto provide lprocessiof agglomerating particles of nitrocellu- Z lose.intoggrains,thi'ough; the agency of nitro-' v glycerine wither without other explosive plastioizersJ- e m erobiefctof this invention is to provide a, smok ess'4'2p'owderfigrainjoomposed of particles ct fdens colloided nitrocellulosepowder together "with ni'troglyi'ine and containing another 2ex-' plosivefpla'sticizer of the nitrotoluene group.

45 Othef objects will become apparent to those skille in the: art' when, the" following description o v ocfe'ss of .this invention is: readand under- 2 st d. 2 .Itis tube understood however, that the embodiments" hereinafter described are illustrato tive onlyigof various embodiments of which this inventio Tisjsuscept iblei In the following descrip:

tion, as;2far, as poss-ible, an explanation will be t given oflljwhat is {believed to be the action taking place from a theoretical standpoint; it isto be that in giving such exlrffobject is to provide aprocess of manu smokeless powders wherein the pro- "to their ignition characterh the agency of an explosivewhich throughout themixture.

' as Claims. (o1. sag-1s) planation the theory and ezrplanation is advanced for'th'e purpose of facilitating an understanding from a theoretical standpoint; and it is understood 'that this invention is not, to be limited to colloided smokeless powder, such for example as scrap cannon powder, may be agglomerated together and formed into gl-rainsfoi the desired size and ignition characteristics in order-to adapt them for use as the propellent in a variety of types of ammunition. Such agglomeration of fine particles of dense smokeless powder, such ascompletel'y gelatinized nitrocellulose,v may be accomplished'by treating the particles with a suitable agglomerating agentwhich may advantageously be a material which ,is a solvent or plasticizi-ng' agent for the dense smokeless powder particles. When such a solvent is employed, the finely divided particles may be surface plasticized and cohered together through the medium of their mutual colloid, in order to accomplish the agglomeration. This operation may-conveniently be carried out in a bath or; water, and it is especially advantageous to employ an agglomerating .solvent which is substantially insoluble inflthe water. When such a mixture is'vigorously agitated; a multitude of the particles of dense smokeless powder aregathered together by the respective globules of solvent, and upon removal of the solvent, as by vaporization; the various particles of dense smokeless powder become autogenously welded into grain form.

During the removal o'f the solvent, such for instance as by evaporation, the tendency is for the several particles of nitrocellulose dust to coalesce or form into small clusters. The extent of this coalescence may be controlled by controlling theviolence of the agitation during the removal of the solvent, and the gravimetric density of the resultant grains may be controlled by regulation 'of the rate of temperature increase and the period of solvent'employed affects not only the size,

shapeand surface of the resultant grains, but also the "gravimetric density thereof.

-The desired amount of solvent may be conveniently added to the slurry oinit'rocellulose dust in the form off'a spray and in this manner small globule'sof theisolvent may be readily distributed During agitation and heating the surfaces of the particles of nitromay, if desired, be incorporated in the mixturein order to effect modification in the granulation which will be accomplished. Among the features which contribute tov the resultant physical char acteristics of the resultant powder grains are the followingz-Small amounts of solvent give a small rough cluster of particles as the grains 7 while larger amounts of solvent give more spherical smoother grains. The faster and more violent the agitation, the smaller the resultant grains. While, as pointed out hereinbefore, the rate at which the temperature is raised during evaporation of the solvent aiiectsboth the granulation and density of the resultant'powder. In

this respect the rapidity with which certain temperatures, such for instance as the boiling point of the mixture of water and solvent, are reached has a particular eiiect upon the density'of the powder. I

' After the mixture has been heated for a time sufficient to accomplish removal of as much of the solvent as may be economically accomplished at this time, the grains may be removed from the. still in which the distillation has been carried out and the water removed therefrom as by centrifuging or wringing. Thereafter the grains may be given a coating for modifying the burning characteristics of the powder and rendering the same non-hygroscopic if desirable. This coating may, for instance, comprise nitroglycerine which acts as an accelerator in that it renders the powder more readily ignitable and also acts as a water proofing agent, rendering the powder nonhygroscopic. A suitable deterrent such, for instance, as dibuty'lphthalate may be used along with the nitroglycerine or other accelerator and water proofing agent. After this is accomplished, the grains may be dried in the usual manner and if desired, glazed and blended in accordance with the usual practice. 1

As an illustrative embodiment of the present invention completely gelatinized nitrocellulose powder, such, for instance, as cannon powder which may be to some extent deteriorated and contain unstable regions may be finely subdivided in a suitable machine, such for instance as a beater, .and preferably to a fineness such as will permit it to pass a sixty-five .mesh' screen. In

, accordance with the present invention the raw material employed may be, for instance, nitrocellulose powder dust which has passed through a sixty-five mesh screen and has been caught on a hundred mesh screen. Furthermore material which is passed through a. hundred mesh screen is suitable for use as the raw ingredient for the process of the presentinvention. ,For

certain purposes it is desirable that the raw material be of a more uniform fineness than under other conditions and accordingly under these circumstances the raw material may be caused to pass through an eighty mean screen and caught on a hundred mesh screen. It is to be understood, however, that for some purposes the raw material may be of a larger size than sixtyfive mesh.

In the case of grains containing only spots of deteriorated material, these acidic portions are likewise broken up thoroughly during the grinding operatings and similarly dispersed or neutralized. Powder on which deterioration has not proceeded to such an extent that visibleregions of discolored material are detectable is, nevertheless, improved in stability through the grinding operation and the contact which is afforded between,

the newly cut and exposed surfaces and the mild alkalinity of the water used in the grinding. The degree of stability of the resultant ground powder depends to some extent upon the degree of fineness to which the material has been ground.

Under ordinary circumstances, however, deteriorated cannon powder which may be used for this purpose will not contain so great a proportion of unstable regions of concentrated acidity that the acidity, when diiiused throughout the entire mass, will be excessive. The local concentrations of acid which are responsible for the unstable character of the gelatinized nitrocellulose powder used as a raw material in the process of this invention are disposed of in this manner. Furthermore, itv may be said that the nitrated diphenylamines are responsible to some extent for the unstable character of the powders. Diphenylamine is aneutral compound, generally employed as a stabilizer for nitrocellulose powders, but which upon nitration becomes'progressively' more acidic in character. Enough diphenylamine is usually present in a grain of ordinary cahnon powder to produce a relatively stable mass if the nitrated and unnitrated diphenylamine were difiused throughout the mass which is accomplished in accordance with this invention.

After grinding and especiallyif a mildly basic substance, such as calcium carbonate is added to the slurry, the resultant mass of nitrocellulose dust is not only stable but the acidity thereof is not above the allowable.

Upon completion of the grinding operation the small particles of cannon powder, which are descriptively termed dust, may be screened in order to obtain particles of the desired fineness. This may be accomplished in any suitable manner, but under ordinary conditions in accordance with the present invention, the dust which is in the form of a mud may be caused to pass a sixtyfive mesh screen and be caught on a'hundred mesh screen; under some circumstances, however, it will be understood that particles either above or below these limits may be employed as the raw material for the process of the present invention.

After the water of the grinding slurry has been permitted to drain from the mass of particles a charge of, for instance 325 pounds of the ground powder-or dust (on a dry weight basis, it being understood that the ground product even after draining isin the form of a mud) may be placed in a still with from seven and one-half to eight times its weight of water. The mixturei nay be agitated in the still to forms. thin slurry and during this time a suitable solvent, such for instance as ethyl acetate, may be added preferably in the form of a spray. It will. be understood that the solvent which may be ethyl acetate may also contain in solution therewith suitable deployed. In accordance with one embodimentot time. the mperaturei of the still FY. dually increaseduntil the ethyl acetate t'ji'corripletely.removed fromthe ointedput her m eror'e, the characteristics '1' sulta'nt powders J especially with I regard nulation andrdensityafreto some 'extentaiiectedby thede'gree' of. fineness of the ust, the rate at which the solvent is .addedlor. inta nasiurry, and by the schedulepf distillation, that istosay, by the manner which, theYtemperature is varied throughout the period, of ltime over which the distillation extends. The distillation. schedule which mayfbelfoundappropriateand efiective to I achieve the desiredgrain characteristics will dependfirpdn-warious other features such as, for instance;, the time andmmount of solventfemployed. As a general rule it will be found that a shortening ofthe distillationschedule will havethe eflectspf reducing the gravimetric density.' Thlsisespecially true of the time. period during which,-fithe solvent-water mixture is passing through its boiling point which, in the case of 1 ethyl acetate is. 69 to 84 C. The same effect may be encountered,-however, byshortening the ancewith the usual practice.

period of timerequiredforraising the temperatureof thegmixture in the still through any selected temperature bracket, but under most circumstances it is .most noticeable during the period atfwhich the solvent-water mixture is passing through its boiling point. As a suitable scheduleaof,,distillation where. ethyl acetate is employed ,asthe solvent the-following is given for the purpose of illustration:

, 1 Minutes From room temperature to 60 CL 45 From fiofjto 74'C; i e e 45. From 74 to 84 C 60 From 84to 95' C 45 In the case of ethyl acetate substantially all oi thesolvent will be found tobe removed in accordancewith the foregoing schedule of distillation when the temperature reaches 95 C. The solvent may, o f course, be recovered in accord- Uponcompletion of ;the distillation just referred tothe contents ofthe still maybe withdrawn and, the water removedtherefrom by any suitable process, such for, instance as by centrifuging whereupon ..the1powder will be found to exist inthe form of grains, each comprising a cluster of the dust particles being substantially uniform in size anddensity, each oi" which characteristicsmay be controlledin the manner hereinbefore set forth...

; ,:In accordance -withthe-present invention the contents of; the stillare withdrawn while a slight trace of the solvent stillremains therein, and

after, thecrmess water has been removed in the manner. just referred tothe grains containing a amount of solvent may becoated with suit- .ablejmodiiying and water proofing agent. For insta ce. the grainsmaybegiven a coating of a deterrent suchfffor. instance} as ,dibutylphthalate with.or{ wi thout,an accelerator to render the grains more readily lgnltable, Nltmglycerine is a suitable acceleratorsince it not only renders the grains more readily lgnitable but also renders the same non-hygroscopic. Furthermore nitroglycerin'e is a good gelatinizer for nitrocellulose, so that it'operates to form a. relatively impervious surface filni on the'grain. The nitroglycerine and dibutylphthalate may be applied as by dissolving them in alcohol with or without benzol. When the dibutylphthalate is employed alone the solvents may, be dispensed with and the substance emulsified with, water. This solution may then befapplied to'the grains which are preferably carried in a medium such, for instance, as a water slurry. Although the nitroglycerine and dibutylphthalate may be'applied tothe grains in the same still in which agglomeration of the dust particles has been carried out, it is preferable that these operationsjbe carried outin separate ves- "sels. The, proportion .of nitroglycerine which is added to the powdermay be from 5% to 20% of the dry weight of the powder, a practical example being it being understood that the nitro 'gly'cerine is preferably handled'in the form of a to 30% solution of alcohol and benzol. The

dibutylphthalate may be added-up to 10% of the dry weight of the powder, a practical proportion being 5%. The resultant grains will be provided with a relatively impervious surface film containing'the nitroglycerine which increases the ignitability and renders the powder non-hygroscopic and with it the dibutylphthalate which operates as a deterrent.

From the foregoing description it will be understood that action of the ethyl acetate is such as to cause the finely divided particles to agglomerate into clusters, forming small grains, and

.also to swell the grains depending upon the amount of solvent employed and the rapidity with which it is distributed throughout the water-nitrocellulose slurry. The amount of swelling which is accomplished determines the final gravimetric density of the powder produced. The agglomerating process of the present invention is admirably adapted for use where a slightly deteriorated cannon powder containing unstable regions is employed for the raw material, since it is apparent that, diffusion of the nitrated and unnitrated diphenylamines and also of the acidity of the unstable regions continues during the treatment in the presence of the solvent. It is probable that the swollen condition of the nitrocellulose due to the treatment with ethyl acetate permits the ready diilusion of acid within that swollen nitrocellulose into the water with which thenitrocellulose is in intimate contact. It is obviousv that, if desired, a suitable amount of neutral diphenylamine may be added to the powder, as for instance with solvent in order to render the powder more stable.

As an illustration. of another embodiment of the process of this invention (claimed in the aforesaid application of Olsen, 'Iibbitts and Kerone, but not-claimed herein) there may be incorporated with the nitrocellulose slurry a small quantity of a protective colloid, such, for instance, as starch. The amount of 'such'protective colloid which may be employed may be as low as one-half to one percent relative to the weight of the water in the slurry of nitrocellulose dust and by use of such protective colloid flocculation is restricted to an extent such that the: esultant grains are finer and of more uniform size.

In accordance with another phase of the present invention, the fine particles of dense colloided nitrocellulose powder may be agglomerated together and formed into grainsby the use of an and causes them to weld together into a grain.

The particles of nitrocellulose may be those resultin from comminution'of dense colloided nitrocellulose such as scrap cannon powder which may be ground to a suitable fineness, as for instance fine enough to pass through a 65 mesh screen. Larger or smaller particles may, however, be used under some circumstances but for a maximum of convenience particles passing a 65 mesh screen are recommended for the raw material to be used in the process of the present invention.

As an illustrative embodiment employing an explosive solvent, in wholeor in part, as the agglomerating agent of the present invention the fine particles of nitrocellulose which may be termed dust" may be suspended as by agitation in a bath of water. The quantity of water may conveniently be from 7 to 8 times the dry weight of the nitrocellulose dust. This mixture may be agitated in a suitable still to form a thin slurry or suspension and, while the agitation continues, the solvent may be introduced in any suitable manner. For instance, the desired amount of nitroglycerine, as for instance 5 to 20%-of weight of nitrocellulose, may be introduced as a straight oil or as a solution thereof in a suitable solvent, such as ethyl acetate or, if desired, the straight oil or solution may be first emulsified in a convenient quantity of water and this emulsion introduced into the bath containing the suspension of nitrocellulose particles.

If the nitroglycerine is'employed in solution in a volatile solvent, such as ethyl acetate, isoproply acetate, butyl formates, or other water insoluble formates and insoluble 'ketones, such as methyl isobutyl ketone, a quantity of solvent about equal to the weight of nitrocellulose to be treated may be employed. In this the desired quantity of nitroglycerine, depending upon the ballistic properties desired, may be dissolved. Each of the aforementioned solvents is substantially insoluble in water and sufliciently volatile that it may be removed by distillation from the water bath below the boiling point of water.

As pointed out'above, the solution of nitroglycerine may be introduced into the water-nitrocellulose suspension while the latter is being agitated. The nitroglycerine solution may be in-- jected as through a suitable spraying device and the continuing agitation of the water nitrocellulose suspension will disperse the nitroglycerine solution in the form of globules throughout the bath. When 7 safety conditions permit the straight nitroglycerine may be likewise introduced in the form of a spray into the bath and the agitation therein may be relied upon to ac complish the desired dispersion in the form of globules. In this case suitable emulsifying agents, such as the oleates, Turkey red oil, Saponin, etc. may be employed, if desired, to accomplish the degree of dispersion desired.

As an alternative procedure the straight nitroglycerine oil or the. nitroglycerine solution may be first emulsified in the convenient quantity of water with suitable emulsifying agents, as mentioncd above, if desired. Thereafter this emulsion or dispersion of nitroglycerine or nitroglycerine solution in water may be introduced into .hereinbefore described.

the water nitrocellulose mixture while 1 agitation of the latter continues.

When the nitroglycerine is employed in the form of a solution in a volatile solvent the temperature of the bath containing thevarlous ingredients may be gradually elevated to a temperature suflicient to vaporize and drive oil the volatile sfllvent fromthe bath. During this time the agitation continues and may becontrolled so as to secure the desired degree of dispersion of the nitroglycerine. In general, the more violent the agitation the smaller the clusters or agglomerates of fine particles which produce the grains. The size of the resultant grains may be controlled by controlling the size of the droplets of the solvent globules since, in most cases, the size of the resultant powder grains'is slightly larger than the globules of the nitroglycerine dispersion. Indeed, if the solvent isemulsifled 'wlth a convenient quantity of waterbefore being introduced into the water-nitrocellulose suspension, practically all of the resulting grains will be slightly larger than the globules of solvent; while, if the solvent is disperseddirectly by agitation in the water nitrocellulose suspension, about of the grains formed will ordinarily be'larger than the droplets or globules of solvent.

vWhile the bath is maintained in a suitable state of suspension and dispersion the temperature may be raised so as to. drive ofiithe volatile solvent. This may be accomplished over a period of three hours or longer, finally reaching" the temperature of boiling of the volatile solvent (but below th boiling point of water).' In the event that the nitroglycerine is employed in the form of straight oil rather than the solution in a volatile solvent, it will be understood that no distillation is'carried out and hence it is only necessary to heat the bath to a suflicient temperature and for a. suflicient length of time to secure thedesired degree of hardening and duced into the bath may also contain suitable amounts of other modifying agents, such as-deterrents, for instance dinitrotoluene, trinitrotoluene, dialkylphthalates, etc., and may" also contain a small quantity of a stabilizing agent, such as diphenylamine, if desired. In some cases where it is not desired to introduce nitroglycerine into the grains the trinitrotoluene or dinitrotoluene may be dissolved in the solvent and may be introducedin the same manner as described above with reference to the nitroglycerine. The amount of such deterrent will be determined by the ballistic characteristics sought but may be up to about 15%. For instance, 8% T. N. T. may be employed with or without the desired quantity of nitroglycerine. Q

As a specific illustration a solution of 30 pounds of nitroglycerine, 15 pounds of D. N. T. or T. N. T. and 1 pounds of diphenylamine may be dissolved in about 300 pounds of ethyl acetate. This solution is sufficient for the treatment of about 300 pounds of nitrocellulose dust.

Moreover, a deterrent substance, such as dinitrotoluene or trinitrotoluene which is normally solid may be employed to agglomerate particles of the nitrocellulose dust so as to produce grains even without employing a volatile solvent as pllshcd by melting the D. N. 'r. or T.N. T. and

This may be accom- "pension "inf that, condition. y I D. N'. 'Tl or' T. N. T. may be introduced directly into the suspension of nitrocellulose in water and introducing it into thefwater nitrocellulose sus- Hence th molten the desired 1 amount of- 'disperslon accomplished is:to 'emulsify the moltenD. N. T. or T. N. T. in a suitableriquantityof hot water so as to secure thedesiredl degree of dispersion or size of globules .as aseparate emulsion and then introduce this into lthe nitrocellulosewater suspension whilethe latteris being agitated.

Incarryingout the process according to this embodiment, wherein the temperature of the bath is maintained above the melting point of an explosiveplas'ticizer, such as D. N. T. or T'. N. T., until the d'esired agglomeration has taken place, hardening oithe grains may be expedited by reducing the temperature of the bath below the melting point of the explosive plasticizer. This 'reduction,=inutemper'ature should, however, not *take plac'eu'until after-the particles have agglomerated to'form grains ofwthe desiredsize 'and become- 'welded to each other through the wagenc'y'of the nitrocellulose surface colloid. When the temperature of the bath is reduced below the melting point of the explosive plasticizer the plasticized nitrocellulose becomes hardened so as to form a' permanent bond between the particles. However,- unless alarge' proportion of explosive plasticizerlis employed, it .is not necessary'to so reduce the-jtemperature in order to harden the grains" 'sin'o'e penetration 'of the-plasticizer into athe particles after surface colloiding will tend to harden"thesurface layers and weld the particles together. i r

Although in the foregoing description referience 'has beenpartly made to the use oijparticles of-clense='-"colloided nitrocellulose, it isto be un- 'derstood-that a-double base powder, suchv for instance; asiBallistite' (nitrocellulose-nitroglycerinel mayi 'be ground to the desired fineness and upon evaporation. of ethyl solution lsluintroduced into the water nitrocellu- 1QSBeSUSPQi9HT8Jld the solution becomes dispersed therein in the .form of droplets, a; plu-v ralityt otj particles or the nitrocellulose dust, will agglomera about, the globules of, nitroglycerine ,tuclg together to produce agrain. latile solvent has been driven off as "lbeenlac'co, plished, to secure-'a'nrmgrain, the

hatinglfandlj, agitation may be discontinued.

Thereafterl.suitable coatings, as for instance.

modi'i'ying age'nts, either deterrents or accelerators, or both, maybe applied in the usual manner tothegrains in order 'to achieve the desired b'alllsticflch' racteristics as described in the prior particles of dense smokelesspowder are adhered together through the agency ofa foreign sub- Lcies; but without restriction as to the agent,

Qti'cles of dense smokeless powder coagmented together, said grains being coated with a combuswillbecome suflicintlya plasticized' weenie: umcient nard nmg has 'copending applications hereinbefore mentioned.

From the foregoing-description, it is apparent that the present invention accomplishes its objects and provides a. method for making propellant powder grains whereby individual dense 5 nitroglycerine, dinitrotoluene or the like therein.

, The powder grains produced in accordance with the present invention are, therefore, small clusters of completely gelatinized particles of nitrocellulose dust. The respective particles which form the individual grains are cemented together by the action of thesolvent to such an extent that, although theresultant grain may be of small size, it is of substantially spherical shape although undulations will exist in the surface thereof. It is to .be understood that this invention is not limited to the details of procedure hereinbefore specifically described for the purpose of illustration but that variations and modifications may be made without departing from the spirit of this invention and that other equivalent explosive plasticizers may be employed with or .withoutthose' mentioned herein. For instance, nitroglycols orainixture of nitroglycols with-nitroglycerine maybe employed wherever nitroglycerine hasbeen described. The words coagmentedf and coagmenting, as used in the ap pended claims, are to be undertsood as implying a condition'inwhich a plurality of individual stance, or cohered togetherlthro'ugh the agency of. the mutual colloid of the particles or by a combination of suchcohesive "and adhesive agenor combination of agents, employed for'accomplishing such adhesion or cohesion, or both. It is to be distinctly understood, therefore, that "such variations and modifications, or the use of such individual features orsubcombinations or features as do not depart from the spirit of this invention are, although not specifically described herein, contemplated by and within the scope of the appended claims. r {Having described the invention, what is claimed is: j v

I 1. A propellant powder grain composed of particles of dense smokeless powder coagmented together. 2.]A propellant powder grain composed of particles of dense smokeless powder coagmented toge'ther, said graincontaining a combustion modifier, T

3. A propellantpowder graincomposed-of partionmodifying a'gent.

4. Apropellant powder grain composed of par ticles of dense smokeless powder coagmented together, said grainbeing coated with nitroglycerine.

5. A propellant powder grain composed of co--' 'agmented particles of dense smokeless powder "and containing a; combustion modifying agent between .the particles.

6; A propellant powder grain composed of coagmented particles of dense smokeless powder,

and containing a deterrent between the particles..- I 7. propellant powder grain composed of pa,r .-7

ticles.

11. A double base smokeless powder in the form of grains comprising finely divided particles of dense colloided nitrocellulose agglomerated by means of an explosive solvent therefor.

12. As a new article of manufacture, grains of smokeless powder suitable for use as propellant powder, said grains comprising, particles of dense colloided nitrocellulose agglomerated together with nitroglycerine.

13. A double base smokeless powder in the form of grains comprising single base nitrocellulose powder fines surface treated withnitroglycerine and agglomerated.

14. A double base smokeless powder in the form of grains comprising single base nitrocellulose powder fines of a size not exceeding about thirty mesh surface treated with nitroglycerine and agglomerated into a plurality of grains.

15. A double base smokeless powder in the form grains comprising single base nitrocellulose powder fines surface colloided with nitroglycerine and agglomerated and bound together through the medium of their surface colloid into grains.

16. In the art of making propellant powder grains, the process comprising, coagmenting particles of dense colloided nitrocellulose dust togather.

1'7. In the art of making propellant powder grains, the process comprising, comminuting dense smokeless powder tov form fine particles,

treating the particles'with a solvent and agglomerating a plurality of individual'particles into grains. l e

18. Inv the art of making'propellant powder grains, the process comprising, comminuting dense smokeless powder toform fine particles, treating the particles with an agglomerating agent and agglomerating the particles into grains.

19. In the art of making propellant powder grains, the process comprising, .coagmenting particles of gelatinized nitrocellulose dust together, and coating the resultant grains with a deterrent.

20.-In the art of making propellant powder grains, the process comprising, agglomerating particles of gelatinized nitrocellulose dust, and coating the resultant grains with an accelerator. 21. In the art of making propellant powder grains, the process comprising, comminutingh.

dense smokeless powder to form fin'e particles, treating the particleswith nitroglycerine, "and agglomerating a plurality of particles together to form grains.

22. The process of making a propellant powder comprising treating fine particles of dense'colloided nitrocellulose with nitroglycerine and'agglomerating a plurality of individual particles into grains.

23. The process of making a propellant powder comprising treating fine particles of colloided nitrocellulose in suspension in nitrocellulose with an explosive solventv therefor and agglomerating a plurality of individual particles into grains. 1 Y

24. In the art of making propellant powder grains, the process comprising, suspendingfinely 1 divided particles of dense colloided nitrocellulose in a body of water, suspending a-.c'ombustion modifying agent in liquid form inthe body of water with the particles of dense colloided nitrocellulose, and agitating the mixture until. the combustion modifying agent attacksand agglomerates the particles of nitrocellulose.

25. A process of making grainsof powder suitable for use as propellant powder, said process comprising, surface plasticizing finely divided 1 dense colloided nitrocellulose with acombustion modifying agent mixed with a volatile solvent for the nitrocellulose while both thenitrocellulose and combustion modifier are suspended by agitation in water, continuing said agitation un- 2 til a plurality of particles of surfaceplasticized nitrocellulose have united together in grain form, then driving oif the volatile solvent for the. nitrocellulose by heat.

26. Theprocess of making grains of powder 2 suitable for use as propellant powder, the process comprising, suspending finely divided dense colloided nitrocellulose in water, mixing an explosive modifying agent with a liquid miscible therewith which is substantially immiscible with water and 3 is likewise a solvent for nitrocellulose, suspending said admixture in the water with the nitrocellulose by agitation, the speed of agitation in relation to the quantity of water used being such as to provide globules of modifying agent and sol- 8 vent suspended in the water, applying heat to drive off the solvent, and maintaining the'suspension by agitation until. hardened colloided powder grains of nitrocellulose and-modifying agent'have been formed. Y

27. A process of making grains of powder suitable for use as propellant powder, said process comprising, treating finely divided dense colloided nitrocellulose with an explosive modifying-agent mixed witlrethyl acetate while both the nitro- 4 cellulose and modifier are suspended by agitation in water, continuing said agitation until grains have been formed, and driving off, the ethyl acetate by heat. 1 T

28.,The process of making grainsof powder suitable for use as propellant powder, which comprises, maintaining finely divided dense colloided water by ..agitation, maintaining a mixture of combustionmodifying agent and a volatile solvent for both the'conibustion modifying agent and the nitrocellulose in suspension in a body of water by agitation, combining saidsuspensions, continuing the agitation until colloided grains of nitrocellulose and oombustion modifying agent have beenfortified,andv 6 driving off the volatile solvent by heat 29. The process of making grains of powder suitable foruse as propellant powden'said process. comprising, suspending finely divided-dense. col- -loided nitrocellulose in water,

suspending nitro- 6 glycerine in water by agitation, controlling'the agitation to produce globules of nitroglycerine slightly smaller than the desired powder grains, admixing said suspensions, and continuing 'the agitation until the nitroglycerine haf'colloided 7 thenitrocellulose into powder grains'."

30. The process of making grains"of powder suitable for use as propellant powder, the process comprising, mixing nitroglycerine with aliquid miscible therewith which is substantially lmmisch 7 cellulose, suspending said admixture in water by agitation,f,the speed of agitation in relation-to thequ'antity of water used being :such as to pro l J vide globules of nitroglycerine and'solvent suspended in the water, the size of the globules being slightly smaller than the size of the desired powder-grains, suspending finely divided dense two suspensions while maintaining the nitro- ,w 'gly'cerinje and solvent in said globular condition,

applying heat to drive off the solvent, and main-- 2, taininglthe suspension by 'agitationuntil hard 1; ened .colloided powder: grains of nitrocellulose and 51' nitroglycerine have. been'IQrmedQ i 1 p31; Ajj process of making grains-f powder suitable'jf org use' as propellant powder, said process" comprising; surface plasticizing; finely, divided g-dense-colldided nitrocellulose with'nitrog'lycerin'e fagitationin water, continuing said agitation un} til grains have been "formedyand, driving, oil the volatileffsolvent for the nitrocellulose by heat,

y; 32.-.'l'he, process of makingggrains of powder 9 suitable-foruse aspropellant powder, theprocess nitrocellulose, s'uspendi'ng said 1 admixturein ingjthejnitroglycerine and solvent in said 81013119 largondition applying heat to drive ofi the sol- Even til hardened colloidedpowder gralns'oi mixed'iwithmthyl acetate while both the nitro== celluloseand nitroglycerine are, ;suspended by" waterfby agitation, the, speed ofa'gi'tation in rela a Jtion to, 'the1 quantity of water being such as to f" provide globules of nitroglycerineandsolvent sus'- pended'in the water, the size-oi the globules ';being slightly smaller than the size of the desired I e {gralns suspending finely divided dense 'iycolloi'de d j.-,nitrocel1ulose in wateri-adding' the, lorme'r suspension to the latter while maintain;

g grains. d maintaining the suspension-by agita- 33. A process of, making grains'oflpowder'suitable for use as propellantpowder, said process, comprising, agitating nitroglycerine in water.

containing finely divided dense colloided nitrocellulose soas to produce globules of nitroglyc.

erine slightlysmaller in size than the desired collolded nitrocellulose in water,-admixing the 34.111 the process of forming propellant powder-grains from colloided nitrocellulose and nitroglycerine in water suspension, a method of lcnnerat'e the finely divided nitrocellulose into grains.

determining the size of the powder grains produced, which method comprises, agitating nitroglycerine in'anaqueous medium to dispersethe nitroglycerine in the form of globules, and maintaming thenitroglycerine in the form or globules of size slightly smaller than the size of the de sired powder grains during the grain forming process. v

35. The process of making grains of powder suitable for use as propellant powder, said process, comprising, treating finely divided dense c01- -loided nitrocellulose in 'water suspension with globules of nitroglycerine slightly smaller in size than that of the desired powder grains.

, 36. The process of making grainsof powder suitable for use as propellant powder, said process, comprising, treating finely divided dense col- .loided nitrocellulose in water suspension with globules of nitroglycerine and a nitroglycerine miscible substantially water immiscible solvent for the nitrocellulose, said globules being slightly smaller in size than that 01 the desired powder 'FREDRICH OLSEN.

. v I CERTIFICATE QFicCRRECTIoN. H

Patent- No". 2,255,298,- "f "Mere hi8, 191:1. .1 i Y :FREDRICH OLSEN;

"It is hei'eby certifiedethat erro'r- 'appers in the printed speci fj efitheebove numbered patent requiring cbrrectimiasfellows; Pagek b1umn, 1ine39 .for isoproplj" reed --igopropyl-+; page 6,irst c line claim 15, for the wo'r d' 'Fform" rea-d--formof" line 60; '01:: f rEPagglqmerating"]read, -ceagmenfiig; line 61; Sahe'clelm, after e d berdre the comma insert -toge'therke-ijand that thesaid Letters sl'loulc'l be reed with thie. correction therein that the same may coni the I 'BO OId of the case inrthe Patent Qffic e. v si ed and sealed this 29th dayof' April, D.- 19m. v

v v Henry V'an Arsdale (segl) 'Actingcomissj pner of I Patent- No. 2,25 ,298;-

'CERTIFICA'IE DF' CORRECTION- v March ,1 191g,

I I .FREDRICH OLSEN. V

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page )4, first column; line 59 for "isopropli" read --ieopropyl--'-; page, first column,

line 35, claim 15, for the woz d 'Pform" read -foI'm oi line 60, claim 20,

forf'agglomerating".read -coagmentihg-q line 61 Same claim, after "dust" 'a; ad before the comma insert --togeth er--; and that the said Letters Patent ehould be read with thiawcorrection therein that the same may-conform to the record of the c se in. the Peltent Office.

Signed and sealed. this 29th 'da of April, ,5. D.- 19m.

Henry Van Arsdale,

(Seal) Actingconnnissioner of Patents.