US3683742A - Process and apparatus for the production of a fuse - Google Patents

Process and apparatus for the production of a fuse Download PDF

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Publication number
US3683742A
US3683742A US33684A US3683742DA US3683742A US 3683742 A US3683742 A US 3683742A US 33684 A US33684 A US 33684A US 3683742D A US3683742D A US 3683742DA US 3683742 A US3683742 A US 3683742A
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Prior art keywords
explosive
thread
feeding means
feeding
fuse
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Expired - Lifetime
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US33684A
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English (en)
Inventor
Wilhelm Rohde
Werner Helfgen
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Dynamit Nobel AG
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Dynamit Nobel AG
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    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C5/00—Fuses, e.g. fuse cords
    • C06C5/08—Devices for the manufacture of fuses

Definitions

  • ABSTRACT The present disclosure is directed to a method and apparatus for manufacturing a fuse containing a very fine, dust-like explosive wherein at least one thread is guided through the explosive to facilitate the introduction of said explosive into the fuse casing.
  • the present invention relates to a process and apparatus for the manufacture of a fuse with a very finegranular or powdery explosive.
  • Fuses are used for the communication of detonations to far removed detonable systems. These fuses exhibit, in a sheath, or so-called casing, a continuous explosive core for propagating the initiating pulse. Depending on the type of the explosive employed and its compression (compacting), a corresponding propagation velocity of the initiating pulse can be obtained. The reliability with which the detonation is completed depends, among other things, on the grain diameter and the amount of the explosive employed, as well as on the diameter of the fuse. Furthermore, the type and construction of the casing of the explosive core are of importance for the advantageous utilization of the explosive properties of the charge.
  • the practice was altered to surrounding a granular explosive core with spun textile and/or natural and/or synthetic fibers.
  • the explosive is introduced from a feeding funnel into a thin strip of paper, synthetic material, or other suitable substances which is continuously wound in a helically overlapping fashion at the lower end of the feeding funnel.
  • This explosive-filled strip is then helically surrounded by various layers of wound or spun textile threads twined from fibers, or like materials.
  • the thus-obtained fuse can then additionally be provided with a coating of varnish, thermoplastic synthetic material, or the like.
  • the fuse may optionally also be provided with a widemesh spun envelope of metallic wires.
  • the type and shape of the explosive employed plays an essential part in connection with the quality of the fuse from the viewpoint of explosive technique, and the reliability of complete detonation of the fuse.
  • pentaerythritol tetranitrate penthrite
  • Hexogen trimethylene trinitramine
  • mannitol hexanitrate and similar substances.
  • a fuse having a core of an explosive in an extremely fine, dust-like phase for example extremely fine penthrite, is superior, with respect to explosive (detonating) quality and with respect to reliable and complete detonation when compared to an explosive core composed of a granular, fluid explosive, since the former exhibits more satisfactory detonating propagation properties.
  • An object of the present invention is to provide an improved process and apparatus for producing a fuse containing a very fine powdery explosive.
  • Another object of the present invention is to provide a process and apparatus for forming an explosive core for a fuse, made of a very fine-grained or dust'like, dry explosive, for example pentaerythritol tetranitrate (extremely fine penthrite) or extremely fine hexogen.
  • the explosive is enclosed is a spun or braided sheath.
  • a further object of the present invention is to provide an improved process and apparatus for producing a fuse which substantially eliminates the uncertainties inherent in the use of fuses containing granular explosives.
  • Still another object of the present invention is to provide an improved process and apparatus for the manufacture of a detonating fuse which uses an explosive which does not exhibit any fluidity in its solid phase.
  • the present invention is directed to a process and apparatus for the manufacture of a fuse having a very fine-grained or dust-like explosive, wherein the explosive is introduced from a filling funnel into a sheath continuously manufactured at the lower end of the funnel.
  • the explosive is introduced from a filling funnel into a sheath continuously manufactured at the lower end of the funnel.
  • at least one thread, deflected from the vertical axis of the feeding funnel (feed hopper) is guided through the feeding funnel preferably in a circular direction and continuously introduced into the sheath at the end of the feeding funnel, together with the explosive. Because of the constant motion of the thread running through the feeding funnel, eccentric with respect to the vertical axis, the cone of explosive is continuously cut, and the explosive dust can be uniformly fed through the funnel due to its inherent weight.
  • any desired amount of charge i.e., explosive weight per 1 meter of fuse, as required by the blasting operation, can be provided.
  • the process and apparatus of the present invention is suitable for the manufacture of low-energy fuses, used, for example, as detonating fuses for base detonation or in areas endangered by firedamp, with charge amounts of 3 g./m. and, in special cases, of less than 1 g./m.
  • a dust-like explosive such as extremely fine penthrite, is the only substance which ensures a reliable complete detonation of very weak explosive cores, which are required, for example, for the prevention of lateral detonation propagations.
  • Heavy-weight charges of the explosive core can also be advantageously produced by the process of the present invention.
  • By the use of the threads a uniform introduction and a uniform distribution of the explosive in the explosive core are ensured.
  • large amounts of charge up to above about 100 g. per meter of fuse can be realized.
  • the process of the present invention developed specifically for the introduction of very fine-grained explosive material into a fuse can also be employed in connection with more granular explosives, since the present process also promotes the uniform flow of the explosive particles into the fuse in these explosives, particularly in case of high loading (charge) weights of the fuse.
  • the present invention it is possible, by the use of dust-like explosive, to produce fuses having a substantially reduced explosive content as compared to fuses utilizing granular, fluid explosive contents, whereby substantial savings in explosive can be achieved. It is thus possible to reduce the weight of the explosive in the explosive core up to about 25 or 30 percent, as compared with the previously conventional fuses utilizing granular, fluid explosive. This is because the dust-like explosive, in connection with such cross sections of the explosive core, will still reliably propagate the detonation completely in those cases where a granular explosive is not able to provide such a complete propagation. Thus, with a reduction in the amount of explosive employed, a more favorable manufacturing expense can be obtained in the production of the explosive fuse.
  • One example of the thread guidance according to the present invention is that at least one thread is circularly guided within the feeding funnel at a short distance from the wall of the feeding funnel, so that the cone of explosive present in the feeding funnel continually is being cut close to its periphery.
  • the principle developed by the present invention is based on the use of one or several threads playing the part of a conveying means. This is effected, according to a further feature of the invention, by roughening the thread surface, so that the thread, during its passage through the dry, dust-like explosive, entrains a certain amount of the explosive. In this manner, the explosive is conducted into the sheath.
  • One property of the thread which facilitates the entrainment of the explosive dust is to provide the thread with a suitable surface characteristic, i.e., a surface which is more or less roughened, and possesses a concomitant sufficient tensile strength, so that the dust particles adhere to the thread.
  • the thread can be drawn off from the storage reel under tension.
  • the thread can be made to vibrate. This is possible, for example, by the selection of a suitable tension for the thread.
  • the vibration of the thread during passage through the funnel filled with explosive dust, sets a certain amount of explosive in motion, depending on the thickness of the thread, the surface characteristics thereof, and the intensity of the vibration, such that the formation of an explosive core about the thread in a uniform fashion is promoted.
  • the motion of the thread in the funnel filled with explosive can be effected in various ways.
  • One possibility resides in guiding the thread on the circumference of a disk provided between the storage reel and the upper opening of the feeding funnel.
  • One embodiment of the present invention provides that the thread is clamped to the circumference of the disk, or is guided in an eyelet or a similar means, and is set into motion by the rotation of the disk.
  • it is just as effective to have the thread rotate about a stationary disk disposed between the storage reel and the upper opening of the feeding funnel.
  • a reciprocatory motion of the disk arranged between the storage reel and the upper opening of the feeding funnel in the vertical direction promotes the uniform feeding of the explosive. This motion can be superimposed, for example, by a circular motion of the thread.
  • Another embodiment of the process of the present invention suggests setting the thread into circular motion by pulling the thread off from a vertically arranged yarn reel (spool) and superimposing on this motion a second motion, preferably circular, by moving the yarn reel holder of the yarn reel.
  • the threads which can be employed are generally twisted from short fibers, such as for example synthetic fibers, natural fibers, or mixtures of natural and synthetic fibers.
  • the synthetic fibers can be mixed with cell wool, wool, flax, and the like.
  • FIG. 1 shows a schematic structure illustrating a process for producing a detonating fuse
  • FIG. 2 shows a modification of the process of the present invention with a superimposed motion of the thread.
  • the dust-like penthrite 1 is contained in a funnel 2 disposed above the spinning plane 7 of the device. Above the funnel 2, the rotating circular disk 5 is provided, the thread 4 being guided over the rim thereof in such a manner that it passes a short distance, for example, only about a few millimeters, from the inner wall of the funnel and extends out of the lower end of the funnel.
  • the storage reel of the thread 4 is attached, in the illustrated example, on the rotating disk 5 by means of the reel holder 6. In this manner, it is ensured that the thread 4 executes a circular motion, and cuts the cone of explosive l in the funnel 2 continuously at its periphery so that the explosive dust can be continuously uniformly replenished, due to its inherent weight.
  • the thread 4 is guided, between the reel holder 6 and the explosive core 8 surrounded by the hose 9, over the circumference of the disk 5 in such a manner that it is under such tension that it is set into slight vibration during the circular guiding procedure.
  • the thread 4 entrains a constantly uniform amount of penthrite dust from the funnel 2.
  • the explosive core is surrounded by a film strip 3 of paper, a synthetic material, or another suitable material. This can be achieved by winding at least one of said materials around the core.
  • cam gears or similar means can also be used, by means of which the thread 4 can be guided within the funnel 2 in the desired manner.
  • FIG. 2 shows a variation of the process of the present invention for the production of a fuse with an explosive core of a dry, very fine-granular or dust-like explosive, operating with refined methods.
  • Two or more arms 11 utilized for receiving the yarn reels 10 are provided in substantially vertical alignment at the reel holder 6, said reel holder being mounted so that it rotates about its longitudinal axis.
  • the thread 4 executes a circular motion about the disk 5 which is connected in a fixed manner with the reel holder 6 and is disposed between the lower end of the yarn reel 10 and the feeding funnel 2.
  • the yarns from which the hose 9 is woven comprise cellulose fibers, cell wool (synthetic wool), nylon, Perlon, rayon, Dralon (polyacrylic fiber), wires of ductile metals, polycarbonates, polyesters, polytetrafluorethylene, and the like.
  • Suitable threads 4 which can be used in the present invention include threads of wool, cell wool, flax hemp, and the like. Synthetic fibers are generally unsuitable due to their character, since they exhibit too smooth a surface. However, if the surfaces of synthetic fibers can be appropriately roughened, said fibers are also useable.
  • a method for manufacturirig a fuse containing a very fine, dust-like explosive which comprises introducing the explosive from a feeding means into a casing disposed at the discharge end of said feeding means, wherein at least one thread having a roughened surface is deflected from the vertical axis of the feeding means, is guided under tension through the feeding means containing the explosive and is continuously introduced into the casing, together with the explosive, at said discharge end of the feeding means, and wherein amounts of the explosive are entrained in the surface of the thread during the passage of the thread through the feeding means into the casing.
  • feeding means is a feeding funnel and the thread is guided in a circular manner through the explosive contained in the feeding funnel and in close proximity to the wall of said funnel so that the cone of explosive present in the feeding funnel is continually cut in the proximity of its periphery.
  • the explosive is selected from the group consisting of pentaerythritol tetranitrate, trimethylene trinatramine, and mannitol hexanitrate.
  • An apparatus for manufacturing a fuse which comprises a feeding means adapted to contain an explosive material, deflecting means for introducing at least one thread, which is deflected from the vertical axis of the feeding means into said feeding means, and means for guiding the thread through the feeding means and continuously introducing the explosive plus the thread into the casing at the discharge end of the feeding means, the thread being provided with a roughened surface for entraining amounts of the explosive during its movement through the feeding means and into the casing.
  • deflecting means is a circular disk disposed above the feeding means and storage reel means are provided for conveying the thread over the periphery of said disk and introducing it into the feeding means.
  • the apparatus of claim 17 including means for vibrating the thread during its passage through the feeding means and into the casing.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
  • Preliminary Treatment Of Fibers (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)
US33684A 1969-05-02 1970-05-01 Process and apparatus for the production of a fuse Expired - Lifetime US3683742A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1922374A DE1922374C3 (de) 1969-05-02 1969-05-02 Verfahren zur Herstellung einer Sprengschnur

Publications (1)

Publication Number Publication Date
US3683742A true US3683742A (en) 1972-08-15

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US33684A Expired - Lifetime US3683742A (en) 1969-05-02 1970-05-01 Process and apparatus for the production of a fuse

Country Status (9)

Country Link
US (1) US3683742A (fr)
AT (1) AT296119B (fr)
BE (1) BE749744A (fr)
CH (1) CH544046A (fr)
DE (1) DE1922374C3 (fr)
FR (1) FR2047205A5 (fr)
GB (1) GB1267132A (fr)
NL (1) NL7005118A (fr)
ZA (1) ZA702959B (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3889571A (en) * 1972-12-07 1975-06-17 African Explosives & Chem Manufacture of safety fuse
US3908509A (en) * 1973-10-29 1975-09-30 Eb Ind Inc Fuse and its method of manufacture
US3995525A (en) * 1974-05-20 1976-12-07 Imperial Chemical Industries Limited Method for manufacturing detonating fuse-cord
US3995526A (en) * 1974-12-23 1976-12-07 Imperial Chemical Industries Limited Method for manufacturing detonating fusecord
US4232606A (en) * 1977-10-17 1980-11-11 E. I. Du Pont De Nemours And Company Explosive connecting cord
US4369688A (en) * 1977-10-17 1983-01-25 E. I. Du Pont De Nemours And Company Method and apparatus for producing a detonating cord
US5473987A (en) * 1990-08-13 1995-12-12 Imperial Chemical Industries Plc Low energy fuse
US5864084A (en) * 1997-04-16 1999-01-26 American Promotional Events, Inc. Glow in the dark fuse and method for making same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4322719C1 (de) * 1993-07-08 1994-10-13 Gnaschwitz Sprengstoffwerk Verfahren zur Herstellung einer Sprengschnur mit verminderter, einstellbarer Detonationsgeschwindigkeit

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1705360A (en) * 1924-10-07 1929-03-12 Fritzsche Johannes Safety fuse and method of manufacturing the same
US3155038A (en) * 1962-09-21 1964-11-03 Ensign Bickford Co Detonating fuse
US3435764A (en) * 1967-11-13 1969-04-01 Ensign Bickford Co Dormant explosive device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1705360A (en) * 1924-10-07 1929-03-12 Fritzsche Johannes Safety fuse and method of manufacturing the same
US3155038A (en) * 1962-09-21 1964-11-03 Ensign Bickford Co Detonating fuse
US3435764A (en) * 1967-11-13 1969-04-01 Ensign Bickford Co Dormant explosive device

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3889571A (en) * 1972-12-07 1975-06-17 African Explosives & Chem Manufacture of safety fuse
US3908509A (en) * 1973-10-29 1975-09-30 Eb Ind Inc Fuse and its method of manufacture
US3995525A (en) * 1974-05-20 1976-12-07 Imperial Chemical Industries Limited Method for manufacturing detonating fuse-cord
US3995526A (en) * 1974-12-23 1976-12-07 Imperial Chemical Industries Limited Method for manufacturing detonating fusecord
US4232606A (en) * 1977-10-17 1980-11-11 E. I. Du Pont De Nemours And Company Explosive connecting cord
US4369688A (en) * 1977-10-17 1983-01-25 E. I. Du Pont De Nemours And Company Method and apparatus for producing a detonating cord
US5473987A (en) * 1990-08-13 1995-12-12 Imperial Chemical Industries Plc Low energy fuse
US5864084A (en) * 1997-04-16 1999-01-26 American Promotional Events, Inc. Glow in the dark fuse and method for making same

Also Published As

Publication number Publication date
DE1922374C3 (de) 1975-09-04
BE749744A (fr) 1970-10-01
ZA702959B (en) 1971-01-27
CH544046A (de) 1973-11-15
DE1922374B2 (de) 1974-09-05
FR2047205A5 (fr) 1971-03-12
NL7005118A (fr) 1970-11-04
GB1267132A (fr) 1972-03-15
AT296119B (de) 1972-01-25
DE1922374A1 (de) 1970-11-12

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