EP0052797B1 - Procédé et dispositif pour la fabrication en continu de poudre de charge propulsive - Google Patents

Procédé et dispositif pour la fabrication en continu de poudre de charge propulsive Download PDF

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Publication number
EP0052797B1
EP0052797B1 EP19810109181 EP81109181A EP0052797B1 EP 0052797 B1 EP0052797 B1 EP 0052797B1 EP 19810109181 EP19810109181 EP 19810109181 EP 81109181 A EP81109181 A EP 81109181A EP 0052797 B1 EP0052797 B1 EP 0052797B1
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EP
European Patent Office
Prior art keywords
section
extruder
solvent
sections
kneading
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19810109181
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German (de)
English (en)
Other versions
EP0052797A1 (fr
Inventor
Dietmar Dr. Dipl. Chem. Müller
Hiltmar Dr.Rer.Nat. Dipl. Chem. Schubert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Original Assignee
Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
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Application filed by Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV filed Critical Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Publication of EP0052797A1 publication Critical patent/EP0052797A1/fr
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Publication of EP0052797B1 publication Critical patent/EP0052797B1/fr
Expired legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
    • C06B21/0033—Shaping the mixture
    • C06B21/0075—Shaping the mixture by extrusion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/22—Extrusion presses; Dies therefor
    • B30B11/24—Extrusion presses; Dies therefor using screws or worms

Definitions

  • the invention relates to a process for the continuous production of propellant powder in the form of a strand by means of an extruder, nitrocellulose moistened with alcohol, mixed with stabilizers and additives, and solvents, e.g. Ketones, ethers, chlorinated hydrocarbons, mixtures thereof or mixtures with alcohol can be added.
  • solvents e.g. Ketones, ethers, chlorinated hydrocarbons, mixtures thereof or mixtures with alcohol can be added.
  • Thermoplastic molding processes or shaping using volatile solvents are used for the production of single-base propellant powder (nitrocellulose), dibasic (nitrocellulose + nitroglycerin or other explosive oils), as well as three-base propellant powder (nitrocellulose + nitroglycerin + nitroguanidine) the latter method is preferred.
  • Ketones, alcohols, ethers or mixtures thereof are generally used as solvents and gelling agents.
  • this method has the safety advantage that the processing temperature can be kept relatively low due to the addition of solvents.
  • pasted nitrocellulose can be extruded into a strand in a screw press (DE-AS 2825567) which, depending on the application, is provided with one, seven or nineteen channels which are formed during extrusion.
  • the invention has for its object to provide a method and a device suitable for its implementation, by means of which propellant powder is obtained in strand form, which on the one hand does not require predrying and on the other hand has a better and reproducible quality.
  • this object is achieved in that the alcohol-moist nitrocellulose is first introduced into the extruder, at least with the additives and, downstream thereof, the solvent, if appropriate with the stabilizers, and before it leaves the extruder the flow movement of the strand is recorded optically and the addition of the solvent is controlled as a function of this recording.
  • the moistening of the nitrocellulose with alcohol serves primarily as a safety precaution.
  • the alcohol content which in the known processes (DE-OS 2446021) is generally 30%, can be reduced to up to 20% or varied in this range without any processing difficulties or safety-related risks.
  • the additives if appropriate also the stabilizers, can be added with the nitrocellulose, but they can also be added in the same advantageous manner only with the solvent. It is also possible to add nitrocellulose, additives and stabilizers to the screw press separately or in a pre-mixed state. With the separate addition of the solvent, it is possible to meter it, which takes place depending on the photo-optically registered flow behavior of the press strand near the outlet end of the screw press.
  • This photo-optical recording can practically determine the viscosity of the product, which in turn depends on the addition of solvent. This can ensure that only so much solvent is added that the strand is still moving at the highest viscosity, ie contains a minimum of solvent. Practical tests have shown that a strand can be obtained in this way that no longer requires predrying and, in particular, can be further processed directly behind the screw press, for example cut to size to form propellant charge powder bodies, granulated or processed in some other way. Finally, with the help of photo-optical recording, malfunctions, e.g. determine whether the pressed material is draining away too quickly or the build-up of traffic jams and take appropriate countermeasures.
  • the invention is based on a known device in the form of an extruder (DE-AS 2825567) which has two co-rotating screw shafts with alternating conveying and kneading sections and two or more addition openings for the components forming the propellant charge powder.
  • an extruder is primarily described as a co-rotating device and is used in particular for processing slurries (explosive sludge).
  • this extruder has been in practical use in the manufacture of propellant powders, all components have been fed to it in a pre-mixed state.
  • the synchronizer places somewhat lower demands on the operating personnel, however the product quality with regard to density and solvent content of the strand when leaving the extruder, as well as with regard to the Dimensional stability (shrinkage) not reached to the extent that is known from counter-rotors in other applications.
  • the use of counter-rotating extruders has so far not been dared for the purpose pursued by the invention.
  • the use of a counter-rotor is possible in that the housing of the extruder has a recess near the outlet end, above which a camera connected to a monitor is arranged, and that an addition opening is connected to a metering device for the solvent.
  • This device-technical measure makes it possible to use the counterpart which is more favorable in terms of homogeneity (no nitrocellulose esters, no air pockets, etc.) and density, without increasing the safety-related risk.
  • the mass is degassed or solvent evaporated via the photo-optical observation opening.
  • the mass leaves the extruder die in strand form at a strand temperature between 50 and 70 ° C.
  • it can also be ensured that the strand temperature does not rise above the upper limit.
  • the change in the chemical composition of the propellant powder strand moves over time within the scope of the analysis accuracy.
  • the HPLC method high pressure liquid chromatography
  • the two screw shafts have a multi-start conveyor section in the area of the recess, which, in conjunction with the optimization of the addition of solvent, prevents the product from escaping into this opening.
  • the multi-start screw shaft geometry in the area of the addition opening for the solvent takes into account the fact that when the solvent is added there is a considerable volume shrinkage, which would otherwise lead to increased air inclusions and thus to inhomogeneities.
  • the relevant mixing and homogenization work is carried out in the kneading section adjoining the multi-course conveying section, while, as already indicated, the subsequent multi-course conveying section below the observation and degassing cutout prevents the product from escaping at this point.
  • the final compression work takes place, so that a homogeneous strand of constant density (up to 1.7 g / cm 3 ) is produced.
  • the shape of the strand depends on the shape of the outlet nozzle of the extruder. In particular, it can also be designed such that a plurality of strands are generated at the same time.
  • a baffle plate is arranged between the first kneading section and the multi-start conveying section at the recess of the extruder, which leads to an increased back pressure in the section of the screw shafts that had previously reached it, and thus to a partial backflow and better mixing.
  • sections without displacement elements are arranged between each of the conveyor sections and between these and the kneading sections.
  • these sections in which the worm shafts are reduced to their core diameter, for example, calming zones are formed which, on the one hand, lead to the reduction of an excessive back pressure, on the other hand, hold back unprocessed nitrocellulose nests or nodules and, due to the increased residence time, also cause them to dissolve.
  • the smooth running of the extruder is improved.
  • the multi-course e.g. three-course conveyor section divided into two conveyor sections and between these in turn a section free of displacement elements is provided.
  • the extruder 1 shown schematically in FIG. 1 has a housing composed of a plurality of segments 2, which are clamped together by end flanges 3 on the end face.
  • the housing has a molding head, not shown, with a die for shaping.
  • the first drive-side housing segment 2 is provided with an addition opening 6 for the solid components, namely nitrocellulose and additives. If necessary, the stabilizers can also be added here, all components being added individually or in a premix.
  • the downstream segment 2 is provided with a nozzle channel 7 through which the solvent, optionally in a mixture with the stabilizers, is fed in in a metered manner.
  • the penultimate housing segment 2 in the conveying direction has a cutout 8, which serves on the one hand for degassing the product and on the other hand for photo-optical recordings of the product passing the cutout 8.
  • a camera 9 is arranged above the opening 8 and is connected to a monitor 10. Based on the recording on the monitor 10, the solvent added via the nozzle channel 7 is metered.
  • the two absolutely symmetrical worm shafts 5 initially have a conveyor section 11 on the drive side, which is of a single-start design. Following this and in the area of the nozzle channel 7 for the solvent, a further conveying section 12 is provided, which is multi-course, in the exemplary embodiment shown three-course and consists of two sections 12a and 12b. A kneading section 13 and another kneading section 14 and then finally a baffle plate 15 then adjoin this multi-course conveying section.
  • the kneading section 14 can also be replaced by a conveying section or an extension of the previous kneading section 13.
  • a three-course conveying section 12 is provided, which is finally closed off from the molding head by a further kneading section 13.
  • the previously described kneading sections can be formed by appropriate shaping of the kneading elements, e.g. as screw, also at the same time conveyor elements.
  • calming zones 16 are provided, in which there are no displacement elements on the screw shafts.
  • the individual sections 11 to 16 are hollow and are drawn onto the worm shafts 5.
  • this can have, for example, a groove or wedge profile, so that the individual sections can be easily assembled.
  • FIG. 2 shows an enlarged view of the conveying section 11 in the area of the feed opening 6 compared to FIG. 1.
  • This is a simple worm screw.
  • FIG. 3 shows the conveying section 12 behind the addition opening 7 for the solvent or in the region of the degassing and observation opening 8. It is multi-course, in the embodiment shown three-course.
  • FIG. 4 shows the middle kneading section 13, which consists of a worm gear with changing profile height 17, 18, 19 or diameter steps, while the kneading section 14 that closes this section has only two extremely wide worm threads 20.
  • the baffle plate 15 is shown in FIG. 6, which has sleeve-shaped projections 16 on both sides. In conjunction with the adjoining sections, these form the calming zones 16 provided there. If necessary, the calming zones 16 can also be formed by simple rings.
  • the length of the individual sections and their combination can be adapted to the respective needs by simple retrofitting.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Extrusion Moulding Of Plastics Or The Like (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Claims (7)

1. Procédé de fabrication ininterrompue de poudre pour charges propulsives par extrusion sous forme de boudin à l'aide d'une extrudeuse, suivant lequel de la nitrocellulose humidifiée avec de l'alcool est mélangée avec des stabilisateurs et d'autres additifs, de manière à former un mélange auquel sont ajoutés des dissolvants, tels que des cétones, éthers ou hydrocarbures chlorés ou des mélanges de ces corps additionnés ou non d'alcool, caractérisé en ce que la nitrocellulose, mouillée avec de l'alcool et contenant au moins les additifs, est introduite dans l'extrudeuse et puis y additionnée du dissolvant, le cas échéant avec les stabilisateurs, en un point situé en aval de son ouverture d'introduction, et en ce que le comportment rhéologique du boudin est contrôlé et enregistré par voie photo-optique en un point situé à proximité de l'ouverture de sortie, dans le but de régler l'addition du dissolvant en fonction de l'information ainsi détectée et enregistrée.
2. Dispositif pour la mise en oeuvre du procédé selon la revendication 1, comportant une extrudeuse équipée de deux vis tournant en des sens opposés et munie d'au moins deux ouvertures d'alimentation pour l'introduction des composants de la poudre pour charges propulsives à fabriquer, caractérisé en ce que l'enveloppe (2) de l'extrudeuse (1) présente une ouverture ou fenêtre (8), située à proximité de l'extrémité de sortie (3), au-dessus de laquelle est disposée une caméra photographique (9) accompagnée d'un moniteur (10), et qu'un dispositif pour le dosage du dissolvant coopère avec une des ouvertures d'alimentation (7).
3. Dispositif selon la revendication 2, caractérisé en ce que les deux vis (5) ont, au niveau de ladite ouverture ou fenêtre (8), une section de transport à plusieurs pas de vis (12); à laquelle se raccorde une section de malaxage (13).
4. Dispositif selon la revendication 2 ou 3, caractérisé en ce que les deux vis (5) comportent au niveau de ladite ouverture (7) pour l'addition du dissolvant plusieurs sections de transport à pas de vis multiples (12a-12b), auxquelles se raccordent des sections de malaxage (13, 14), ainsi qu'une autre section de transport à pas de vis multiples (12) commençant devant ladite ouverture ou fenêtre (8), et finalement une dernière section de malaxage (13) située en aval de cette ouverture ou fenêtre (8).
5. Dispositif selon l'une ou l'autre des revendications précédentes 2 à 4, caractérisé en ce qu'entre la première section de malaxage (13, 14) et la section de transport à plusieurs pas de vis (12) au niveau de ladite ouverture ou fenêtre (8) de l'extrudeuse (1) est prévu un disque de retenue (15).
6. Dispositif selon l'une ou l'autre des revendications précédentes 2 à 5, caractérisé en ce qu'entre les sections de transport (11, 12) et entre ces dernières et les sections de malaxage (13, 14) sont prévues des zones de modération (16) dépourvues d'éléments de refoulement.
7. Dispositif selon l'une ou l'autre des revendications 4 à 6, caractérisé en ce que la section de transport à plusieurs pas de vis (12), située au niveau de ladite ouverture d'addition du dissolvant (7), est divisée en deux sections de transport (12a, 12b) séparées par une zone libre (16) dépourvue d'éléments de refoulement.
EP19810109181 1980-11-26 1981-10-29 Procédé et dispositif pour la fabrication en continu de poudre de charge propulsive Expired EP0052797B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3044577 1980-11-26
DE19803044577 DE3044577C2 (de) 1980-11-26 1980-11-26 Verfahren und Vorrichtung zur kontinuierlichen Herstellung von Treibladungspulver

Publications (2)

Publication Number Publication Date
EP0052797A1 EP0052797A1 (fr) 1982-06-02
EP0052797B1 true EP0052797B1 (fr) 1984-03-28

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EP19810109181 Expired EP0052797B1 (fr) 1980-11-26 1981-10-29 Procédé et dispositif pour la fabrication en continu de poudre de charge propulsive

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EP (1) EP0052797B1 (fr)
DE (1) DE3044577C2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2212393C2 (ru) * 2001-01-29 2003-09-20 Государственный научно-исследовательский институт химических продуктов Способ получения одноосновного высокоазотного пироксилинового пороха

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3225065C1 (de) * 1982-07-05 1983-12-15 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., 8000 München Vorrichtung zum Entwaessern und Plastifizieren von Explosivstoffgemischen
DE3242301A1 (de) * 1982-11-16 1984-05-17 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., 8000 München Verfahren und vorrichtung zur herstellung ein- oder mehrbasiger treibladungspulver
DE3407238A1 (de) * 1984-02-28 1985-11-21 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., 8000 München Vorrichtung zum herstellen von treibladungspulver in strangform
DE3412410C2 (de) * 1984-04-03 1987-01-22 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., 8000 München Verfahren zur Herstellung kunststoffgebundener Treibladungspulver und Sprengstoffe
DE3913603C1 (fr) * 1989-04-25 1990-03-29 Wnc-Nitrochemie Gmbh, 8261 Aschau, De
RU2156230C2 (ru) * 1996-12-19 2000-09-20 Общество с ограниченной ответственностью "Бисертон" Способ получения пироксилинового пористого пороха для патронов к стрелковому оружию
RU2165402C2 (ru) * 1999-01-18 2001-04-20 Государственный научно-исследовательский институт химических продуктов Способ получения пироксилинового пористого пороха для патронов к стрелковому оружию

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2825567B1 (de) * 1978-06-10 1979-11-15 Dynamit Nobel Ag Verfahren zur kontinuierlichen Herstellung von Explosivstoffgemischen

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2212393C2 (ru) * 2001-01-29 2003-09-20 Государственный научно-исследовательский институт химических продуктов Способ получения одноосновного высокоазотного пироксилинового пороха

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Publication number Publication date
EP0052797A1 (fr) 1982-06-02
DE3044577A1 (de) 1982-07-15
DE3044577C2 (de) 1982-11-11

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