US1308344A - Process-of making - Google Patents

Description

F. l. 4DU PONT.

PROCESS 0F MAKINGSIVIOI-(ELESS POWDER.

APPLICATION FILED MAH, 1915.

mmmlm Patented July l, 1919i.

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lillv FRANCIS I. DU PONT, OF WILMINGTON, DELAWARE, .ASSIGNOBABY DIRECT AND MESNE ASSIGNMENTS, TO BALL. GRAIN EXPLOSIVES COMPANY, OF WILMINGTON, DELA- WLRE, A CORPORATION OF DELAWARE.

PROCESS OF IVIAKINGSMOKELESS POWDER.

Specification of Letters Patent.

Patented July 1,1919.

applieation'fued May a, 1916. l serial no. 94,946.

To all whom t may concern.'

Be it known that I, FRANGIs ll. DU PONT,

a citizen of the United States, residing at.

Wilmington, county of New Castle, and State of Delaware, have invented a new and useful Improvement in Processes ofj Making Sme eless Powder, of'which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which vform a -partof this specification.

ln'the manufacture of smokeless powder it is well known to partly remove the water 'from the nitrocellulose by wringing in a centrifugal machine, then displacethe remaining water with alcohol by percolation withy pressure to form #a cake containing from 20- to 25 per cent. alcohol, then breaking up the same, and then mixing with the alcoholized nitrocellulose ether in amount equal to about twice the amount of alcohol,-

,then alcohol, and later with the alcohol.

This reversal of. the old processY possesses a great advantage in that the excess of ether can be removed with but aV small fraction ofthe pressure required to remove the,

excess of alcohol in the old process. It is also associated with other novel steps,where by the 'above results are secured and whereby also the volume of ether to a given Weight of nitrocellulose may be accurately predetermined.

'lo carry out my invention l have provided a novel apparatus, an understanding of the construction and operation of which will enable the essential features of the process to 'be more readily comprehended. In the drawings: y

Figure l is a side elevation, lpartly in section, o'f the major part of the apparatus. Fig. 2 is a similar view, somewhat diagrammatic, of the mixing machine. Fig.

' 3 is a side view of the hopper. Fig. 4c is an end view of the drier. Fig. 5 is a gitudinal section of the drier.

The nitrocellulose is wrung in a cent-rifuv gal machine (not shown), as heretofore, to expel as much of the water as is practicable. say until it contains about 25 per cent. mois-l ture. rlhe nitrocellulose isthen transferred to a hopper a, having its bottom closed by an endless carrier b, which, with the roller c, transfers the nitrocellulose' in a slow and measured stream from the hopper to the drier.

The drier is essentially a long stationary cylinderl ai through the axis of which extends a rotary power driven shaft c having spokes f to which are secured a worm g extendingclose to the inner wall of the cylpartial lon- -inder. rlFhe cylinder is supported on a frame work it irlclosing a heated cham'ber through which extend heating pipes e'. Warm air may also be introduced into the discharge end of the cylinder through the pipe cl and caused to circulate through the same in the opposite direction to that of the travel of the nitrocellulose. rl`he wall of the cylinder is made of very thin sheet metal so that in the event of an explosion it will readily rupture. I

The discharge end of the Ydrying cylinder may have .a dis-charge chute j provided with rotary feed blades 7c for delivering the nitrocellulose without permitting escape of the warm air used for drying, into a funnel m opening into the top of a tank o. Within the funnel m is a power driven cork screw-like device n.

The tank o is maintained full of ether, whicheXtends upvin'to the funnel m and also into an overflow device p. Within the tank is a rotary agitator g.

'lhe device n causes the dry nitrocellulose to mix with the ether. During the feeding and drying operation the agitator g remains stationary.- Thus the nitrocellulose settles to the bottom,and.the pure ether displaced by Ithe nitrocellulose escapes from the tank by way of the overflow p.

After the tank o has received the maximumdesigned amount of nitrocellulose, the feeding mechanism is stopped and the `agitator g started so as to thoroughlymechani cally mix the nitrocellulose and ether, it beingl understood that the nitrocellulose 'is not soluble in ether alone.

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Communicating with the bottom of tank o is a tank s, communication between the tanks being controlled by a plug valve fr. The tank s is simlilar in construction to the tank o, but is-unprovided with an overflow. It does have, however, an agitator t, similar to agitator 'y in tank o. tank s is a spout o, controlled by a plug valve Vu, discharging into a. press, the latter comprising a cylinder w having a -pivoted top and a pi-ston x provided with a strainer.

A sample of known volume may be taken from tank s to ascertain the weight of nitrocellulose therein. It is thus possible to use the press as a. measure to determine a definite weight of nitrocellulose. to a calculated volume the press will deliver a definite Weight of nitrocellulose wetted with a definite volume of ether.

The cakes formed in the press are then -transferred to any suitalble mixing machine. A mixer constructed on the yprinciple of a bread mixing machine is preferable, such a machine being shown somewhat diagrammatically in Fig 2, in which y represents the receptacle and a, a, tW-o 'blades rotating therein' in opposite directions, at different angular speeds. In this machine the predetermined quantity of alcohol, which should equal one-half the volume of ether contained in the cake received from the press, is added gradually. I

In the above description of the apparatusand its `operation the several steps of the process have been incidentally described with suiicient detail to enable the essential features of the processto be clearly understood. It is, however, unnecessary toemploy mechanism of any particular construction to carry out the process, but the mecha.-

nism described presents features of decided utility and advantage.

The pressure required to eliminate the excess of ether is substantially less than is requiredin the old process hereinbefore mentioned to get rid of the excess of alcohol. The pressure being substantially less,- a. hard mass is not formed and no lumps of unmixed material are contained in the finished product.

While I have referred to ether and alcohol as the liquids which together form a solvent forthe nitrocellulose, it will 'be understood In the bottom of By pressure that my invention comprehends the use of other liquids having respectively equivalent properties.

The drier herein described is the subjectmatter of a separate application filed July 18, 1917, Serial No. 181,227.

Having now fully described my invention, what I claim and desire to protect by Letters Patent is:

1. The process of manufacturing` smokeless powder, whichconsists in first mixing nitrocellulose with ether, then expelling the excess of ether with pressure, and then mixing the; nitrocellulose with alcohol to form a gelatinous or colloidal mass.

2. The process of mainifacturing smokeless powder, which consists in drying nitrocellulose, mixing it with ether, compressing the nitrocellulose to eliminate the excess of ether, and breaking' up the compressed nitrocellulose and mixing it with alcohol to gelatinize or colloidize the nitrocellulose.

3. The process of manufacturing smokeless powder, which consists in drying nitrocellulose, conveying it to a body of ether, agitating the ether and nitrocellulose to effect their mixture, pressing successive fractional quantities of the entire mixture to expel therefrom the excess of ether, and then breaking up the compressed nitrocellulose i and adding alcohol thereto.

4. The process of manufacturing smokeless powder, which consists in feeding the same to a body of ether and 'during said feed-ing driving off water by means of hea-t, agitating the ether and nitrocellulose to effect their mixture, pressing successive fractional quantities of the mixture to expel therefrom the excess of ether, and then breaking up the pressed cakes and mixing therewith alcohol. y

5. The process of manufacturing smokeless powder, which consists in first drying nitrocellulose, then immersing the same in a body of ether and mechanically mixing it therewith, then compressing the nitrocellulose to expel the excess of ether, and then mixing with alcohol the nitrocellulose which has been thus wetted with ether.

I n testimony of which invention, I have hereunto set my hand, at Philadelphia, on this 27th day of April, 1916.

FRANCIS I. DU PONT.

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