Societe Nationale Des Poudres Et Explosifs

Michel B Maures

Alain Brasquies

Francois A Pollozec

Remy Favrot

Andre J Mengelle

Gontran Royer

Hubert Delarche

Patrick Lespinasse

Jacques Pasdeloup

Thierry Bonnabaud

Francois Gendreau

The invention relates to the field of combustible ammunition and relates chiefly to the manufacture of bottoms or covers for combustible cases. According to the invention, a combustible article is manufactured by pressing in a die 10 at least one sheet 21 of combustible paper containing nitrocellulose and having the shape of a disc, by virtue of a rigid movable punch 20 exerting a compressive force on a deformable flexible punch 22 arranged inside the said die 10 between the sheets 21 and the said movable punch 20. The flexible punch 22 is in the shape of a substantially cylindrical thick disc, consists of neoprene or a silicone resin and has a hardness of between 55 and 65 Shore at 20.degree. C. The pressing operation is accompanied by a thermoforming operation carried out at approximately 115.degree. C. The process is particularly suitable for the production of bottoms of combustible cases bearing studs or grooves on their side faces.

Process for the manufacture of combustible articles by pressing

Process for the manufacture of combustible articles by embossing combustible paper and combustible articles thus produced. The invention relates to a process for the manufacture of combustible dish-shaped articles of revolution with circular external outlines from combustible paper containing nitrocellulose by embossing at least one combustible paper disc 11 comprising a central part 12 and a peripheral part consisting of a plurality of portions 13 separated from each other by radial slits 14 the length 'L' of which is smaller than the radius 'R' of the said disc 11 and the width 'e' in which is at least equal to the minimum width required to prevent the overlapping of the said portions 13 when the disc 11 is deformed by embossing. The invention also relates to combustible dish-shaped articles of revolution with circular external out-lines, consisting of at least one sheet of combustible paper containing nitrocellulose and in particular those produced by the process according to the invention. These articles have their essential application as components for combustible cases and especially as combustible bottoms or as combustible lids.

Process for the manufacture of combustible articles by embossing

This invention relates to combustible or semi-combustible cases intended in particular for artillery ammunition. More specifically, the invention relates to combustible cases bodies obtained by spirally winding combustible paper tapes containing nitrocellulose and having an improved mechanical resistance relative to previous combustible tape bodies, thanks to the fact that the combustible paper tapes form three distinct coaxial layers in terms of their density and structure. The case bodies according to the invention are obtained by spiral winding around a mandrel 80 a sheet 70 consisting of an uncalendered combustible paper tape 41 and six calendered combustible paper tapes 42-47 with density between 0.9 and 1.2 g/cm.sup.3, the tapes being pasted to each other according to a helical angle .alpha. such that the helical pitch P is larger than the width w1 of the tape 41 which thus forms a helix with turns which are not joined together. A calendered combustible paper tape 71 previously pasted with density lying between 1.15 g/cm.sup.3 and 1.3 g/cm.sup.3 is then spirally wound around the tube thus formed according to the a helical angle .beta. such that the turns of the helix formed by the said tape 71 overlap. The tube thus formed is then cut to the desired length of the case body.

Combustible or semi-combustible case bodies consisting of a large number

According to the invention the reels 10 of cellulose thread wound in a loose manner around a hollow perforated core are arranged on the nozzles 9 carried by the hollow arms 8 of a rotor 7a placed on a hollow frame 7 situated at the bottom of a tank 6. A pump 13 causes the nitrating medium 15 consisting of a mixture of nitric acid and methylene chloride to circulate into the pipe 14 from where it passes into the frame 7 and then to the rotor 7a from where it is brought under pressure via the pipes 8 and the nozzles 9 to the hollow perforated core of each reel. The nitrating medium then passes radially along the mass of thread making up each reel and returns to the pump 13 via the pipes 12. After nitration the nitrocellulose threads are immediately stabilized by washing them with water in a similar installation to that used for nitration. The process according to the invention makes it possible to manufacture reels of nitrocellulose thread of good quality in a simple manner in large quantities without the manufacturer having to perform delicate unwinding and reeling operations on the thread before and after nitration.

Process for the manufacture of reels of nitrocellulose thread

In a continuous process for the nitration of cellulose, a slurry of cellulose in nitrating liquor is injected under pressure into a primary nitration reactor by means of an injection pump, the reactor comprising a loop of tubing, the slurry is circulated in the loop by means of a circulation pump at a rate which is greater than the rate of injection in order to ensure that the slurry is vigorously agitated, the slurry is optionally transferred, successively, from the primary loop to one or more secondary nitration reactors, each of which also comprises a loop of tubing equipped with a circulation pump, and the slurry is withdrawn from the final loop and the nitrocellulose is recovered.

Growing community of inventors

Bergerac, France

Michel B Maures