US3730097A - Fuze for use in firedamp-endangered and coal-dust-endangered operations - Google Patents

Fuze for use in firedamp-endangered and coal-dust-endangered operations Download PDF

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Publication number
US3730097A
US3730097A US00193460A US3730097DA US3730097A US 3730097 A US3730097 A US 3730097A US 00193460 A US00193460 A US 00193460A US 3730097D A US3730097D A US 3730097DA US 3730097 A US3730097 A US 3730097A
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US
United States
Prior art keywords
explosive
fuze
fuze according
casing
synthetic resin
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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 - Lifetime
Application number
US00193460A
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English (en)
Inventor
W Helfgeni
W Rohde
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Dynamit Nobel AG
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Dynamit Nobel AG
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Publication date
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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
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B25/00—Compositions containing a nitrated organic compound
    • C06B25/32—Compositions containing a nitrated organic compound the compound being nitrated pentaerythritol
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C5/00—Fuses, e.g. fuse cords
    • C06C5/04—Detonating fuses
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C5/00—Fuses, e.g. fuse cords
    • C06C5/06—Fuse igniting means; Fuse connectors

Definitions

  • the envelope is, preferably, a mixture 0 L C in n In.
  • a fuze (priming cord) which does not represent any danger for mine gas mixtures (firedamp) at the given length of the shot holes, e.g. 20 m., is suitable.
  • the fuze must be firedamp-proof.
  • the fuze must be able to initiate with certainty all conventional and mining-approved explosives of classes II and Ill.
  • the present invention is based on the problem of developing a fuze which meets all demands from the viewpoint of blasting technology and simultaneously possesses a maximum degree of firedamp dafety.
  • the fuze of the present invention is characterized by a core cord having a strongly reduced explosive weight per meter of fuze, of a powdery desensitized explosive, with a hollow tube centrally disposed within the explosive core and a casing of inert substances having a flash-reducing (flame-cooling) and flame-baffling ef-- feet.
  • the combination of the individual features of the core cord and the casing, as well as their mutual adaptation result in a surprising increase in the firedamp safety of the fuze which has not existed heretofore.
  • the individually provided measures result, by their cooperation, in the special, firedampproof characteristics.
  • the starting point is the quantity of the explosive to be utilized. Since the capability of an explosive to ignite firedamp does not solely depend on the brisance and explosion temperatures, but is influenced to the same extent by the amount of the explosive employed, the core cord of this invention is equipped with an explosive core having an explosive weight which is strongly reduced as compared to the customary fuze, ranging preferably between 2 to 5 g. per meter. With such an amount, a compact, solid explosive core will assume outer diameters ofonly 2.6 to 3.0 mm.
  • a second measure is provided, namely the use of a powdery explosive in an extremely finely divided form, wherein at least 60 percent of the explosive passes through a mesh screen of 0.074 mm.
  • a suitable explosive is, for example, penthrite.
  • the third measure essential to the present invention is the addition of a desensitized substance to the powdery explosive.
  • a desensitized substance for this purpose, all materials can be employed which genuinely reduce the brisance of the explosive, such as, cryolite, all halogenides, sulfates, bicarbonates, carbonates, and phosphates of the alkali metals and alkaline earth metals, the corresponding ammonium salts, and all oxides of the alkaline earth metals.
  • care is to be taken in the selection of the desensitizirtg substance so that, with a minimum quantity of additive, a satisfactory desensitization is effected without endangering the complete detonation or detonation propagation of the explosive core.
  • Cryolite proved especially suitable since it exhibits excellent flame-cooling properties.
  • the fourth essential measure is the central arrangement of an endless hollow tube in the explosive core.
  • This hollow tube provides, as a result of its characteristic, a hollow-charge effect, i.e. the tube effects, up to a certain extent, a directional shot which focuses a large portion of the energy liberated during the reaction of the explosive in the axial direction of the fuze and thus strongly reduces the normal uniform lateral effect.
  • This hollow tube which must be adapted to the diameter of the explosive core with respect to its diameter, exhibits an optimum efficiency in cooperation with the explosive employed when occupying about one-third of the total (or outside) diameter of the explosive core.
  • the hollow tube consists, for example, of any desired, deformable and stretchable synthetic resin and is uniformly round and disposed as centrally as possible within the explosive core. This tube should furthermore exhibit a uniformly round hollow channel which is not constricted or interrupted by pressure, bending or other mechanical influences.
  • the thus-formed core cord is surrounded, in a fifth measure essential to the present invention, by a casing of inert substances having a flame-cooling and flamebaffling effect.
  • the important feature of this casing is the density of the envelope of gas vapors and firing vapors formed by the vaporization of the inert substances.
  • a dense envelope is capable of absorbing residual, laterally effective energies, hot explosion gases and glowing particles of the core cord to shield and screen off the same against any existing explosive gas mixtures, e.g., firedamp.
  • the inert substances suitable for producing such a dense envelope all the materials set forth above for the desensitization of the explosive can be employed.
  • thermosetting and thermoplastic synthetic resins being suitable, admixed in an extremely fine distribution to the other inert substances in a percentage of S- percent based on the weight of the other inert substances.
  • Synthetic resins on the basis of polyacrolynitrile with styrene and butadiene or ABS- polymers are particularly preferable.
  • other heat-resistant plastics can be successfully utilized in this connection, for example, polytetrafluoroethylene, or copolymers of polyacrylonitrile.
  • the encased core cord is advantageously surrounded by an outer shell, e.g., of extruded plastic, such as soft PVC.
  • the foundation of the so-called core cord is formed by the plastic hollow tube 1 disposed centrally with respect to the longitudinal axis.
  • Tube 1 is surrounded and guided by several threads 2 which, in turn, are surrounded by explosive core 3 of, for example, a uniform mixture of 4 g. of extremely fine penthrite with percent (0.4 g.) of cryolite, per running meter of fuze.
  • explosive core 3 of, for example, a uniform mixture of 4 g. of extremely fine penthrite with percent (0.4 g.) of cryolite, per running meter of fuze.
  • the strip 4 of plastic e.g., hard PVC, encases, wound in overlapping windings, the explosive core 3.
  • the multiple-layer spun casing 5 of natural and/or synthetic fibers forms the outer cover of the core cord.
  • the envelope of the core cord is constituted by the jacket composition 7 of inert substances, e.g., 8 g. per running meter of fuze of a mixture of 50 percent ABS (acrylonitrile-butadiene-styrene) polymer, percent cryolite and 30 percent sodium chloride. This mixture is likewise guided in the axial direction by several threads 6, for example of cellulose-base fibers.
  • the cover of the fuze comprises: strip 8 of a plastic film, e.g., hard PVC, wound in overlapping windings; the multiple-layer spun envelope 9 of threads of synthetic and/or natural fibers; and the waterproof outer shell 10, e.g., of soft PVC.
  • a thus-constructed fuze exhibits a detonation velocity of 6000 i 600 m./sec., a tensile strength of 100 :t 20 kp./cm. and an outer diameter of about 5.8 mm.
  • the fuze of this invention which is' distinguished by an especially high degree of firedamp safety, was tested in the chamber of an explosive testing range in various arrangements having 9 9.5 percent firedamp concentrations.
  • the covering method is advantageously employed, wherein the explosive is introduced from a feeding funnel into a thin strip of paper, plastic or another suitable material which is continuously helically wound in overlapping windings at the lower end of the funnel.
  • the explosivefilled strip is then provided with a cover of various layers of textile threads or the like twisted from fibers, which are helically wound or spun therearound.
  • the core cord is encased with the inert mixture of substances in the same manner, and the thus-obtained fuze additionally provided with a coat of varnish, a thermoplastic synthetic resin or the like.
  • the powdery explosive utilized does not exhibit fluidity it is introduced into the core cord from the feeding funnel by means of transporting threads with a rough surface traveling through the filling funnel under tension and vibration.
  • transporting threads exhibits the additional advantage that these threads enhance the central positioning of the hollow tube within the core fuze, since the threads simultaneously constitute a support for the hollow tube.
  • a fuze for use in firedampand coal-dust-endangered operations comprising an explosive core having a hollow center and including a powdery desensitized explosive of a strongly reduced explosive weight per meter of fuze, a hollow tube disposed within the hollow center of said explosive core, and a casing of inert substances surrounding said explosive core and having a flame-cooling and flame-baffling effect.
  • a fuze according to claim 4 wherein 10 percent by weight of cryolite based on the weight of explosive is added to said explosive.
  • a fuze according to claim 1 wherein said casing is comprised of a mixture of at least one powdery synthetic resin and at least one substance selected from the group consisting of cryolite, halogenides, sulfates, bicarbonates, and carbonates of the alkali and alkaline earth metals, the corresponding ammonium salts, and all oxides of the alkaline earth metals.
  • a fuze according to claim 8 wherein between about 5 percent and about 70 percent of synthetic resin particles are admixed with said at least one inert substance.
  • a fuze according to claim 8 wherein said at least one synthetic resin is based on polyacrylonitrile with styrene and butadiene.
  • a fuze according to claim 1 further comprising an outer shell of extruded synthetic resin disposed around said casing.
  • a fuze according to claim 1 further comprising a strip of wound plastic disposed between said explosive core and said casing of inert substances.
  • a fuze according to claim 12 further comprising a multiple-layer spun envelope of synthetic or natural threads positioned between said strip of wound plastic and said casing of inert substances.
  • a fuze according to claim 13 further comprising a second strip of wound plastic covering said casing of inert substances.
  • a fuze according to claim 14 further comprising a second multiple-layer spun envelope of synthetic or natural threads encasing said second strip of wound plastic.
  • a fuze according to claim 15 further comprising an outer shell of extruded synthetic resin disposed around said second multiple-layer spun envelope.
  • a fuze according to claim 16 further comprising first and second thread groups, respectively, wound in a manner so as to guide the distribution of said powdery desensitized explosive and said inert substances.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Air Bags (AREA)
  • Ropes Or Cables (AREA)
  • Materials For Medical Uses (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Chemical Or Physical Treatment Of Fibers (AREA)
  • Compositions Of Oxide Ceramics (AREA)
US00193460A 1970-11-20 1971-10-28 Fuze for use in firedamp-endangered and coal-dust-endangered operations Expired - Lifetime US3730097A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2057042A DE2057042C3 (de) 1970-11-20 1970-11-20 Sprengschnur für den Einsatz in Schlagwetter- und kohlenstaubgefährdeten Betrieben

Publications (1)

Publication Number Publication Date
US3730097A true US3730097A (en) 1973-05-01

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Family Applications (1)

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US00193460A Expired - Lifetime US3730097A (en) 1970-11-20 1971-10-28 Fuze for use in firedamp-endangered and coal-dust-endangered operations

Country Status (8)

Country Link
US (1) US3730097A (de)
BE (1) BE775433A (de)
CS (1) CS159294B2 (de)
DE (1) DE2057042C3 (de)
FR (1) FR2114857A5 (de)
GB (1) GB1321526A (de)
PL (1) PL81423B1 (de)
SU (1) SU464102A3 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3867884A (en) * 1973-02-19 1975-02-25 Ici Ltd Explosive fuse-cord
US4083305A (en) * 1976-04-28 1978-04-11 Teledyne Mccormick Selph, An Operating Division Of Teledyne Ind. Inc. Mild detonating cord confinement
US4102428A (en) * 1976-11-03 1978-07-25 Ensign-Bickford Company No-flash seismic cord
US4178853A (en) * 1976-04-28 1979-12-18 Teledyne Mccormick Selph, An Operating Division Of Teledyne Industries, Inc. Mild detonating cord confinement

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1396471A (en) * 1973-02-19 1975-06-04 Ici Ltd Exposive fuse-cord
DE2529039A1 (de) * 1975-06-28 1977-01-20 Dynamit Nobel Ag Wettersprengstoffe
DE3020957C2 (de) * 1980-06-03 1983-03-03 Dynamit Nobel Ag, 5210 Troisdorf Wasserfeste Sprengschnur
DE102005040392A1 (de) * 2005-08-25 2007-05-03 Dynaenergetics Gmbh & Co. Kg Sprengschnur zur Behandlung von schlecht erreichbaren Oberflächen
DE102006007483B4 (de) * 2006-02-17 2010-02-11 Atc Establishment Zündschlauch

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2380312A (en) * 1942-11-19 1945-07-10 Du Pont Detonating fuse
US2891475A (en) * 1954-02-01 1959-06-23 Ici Ltd Fuse
US3027839A (en) * 1959-04-02 1962-04-03 Andrew J Grandy Tubular explosive transmission line
US3344005A (en) * 1966-02-23 1967-09-26 Trojan Powder Co Pentaerythritol tetranitrate-trimethylolethane trinitrate explosives
DE1916685A1 (de) * 1969-04-01 1970-12-10 Dynamit Nobel Ag Sprengschnur
US3590739A (en) * 1967-07-20 1971-07-06 Nitro Nobel Ab Fuse

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2380312A (en) * 1942-11-19 1945-07-10 Du Pont Detonating fuse
US2891475A (en) * 1954-02-01 1959-06-23 Ici Ltd Fuse
US3027839A (en) * 1959-04-02 1962-04-03 Andrew J Grandy Tubular explosive transmission line
US3344005A (en) * 1966-02-23 1967-09-26 Trojan Powder Co Pentaerythritol tetranitrate-trimethylolethane trinitrate explosives
US3590739A (en) * 1967-07-20 1971-07-06 Nitro Nobel Ab Fuse
DE1916685A1 (de) * 1969-04-01 1970-12-10 Dynamit Nobel Ag Sprengschnur

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3867884A (en) * 1973-02-19 1975-02-25 Ici Ltd Explosive fuse-cord
US4083305A (en) * 1976-04-28 1978-04-11 Teledyne Mccormick Selph, An Operating Division Of Teledyne Ind. Inc. Mild detonating cord confinement
US4178853A (en) * 1976-04-28 1979-12-18 Teledyne Mccormick Selph, An Operating Division Of Teledyne Industries, Inc. Mild detonating cord confinement
US4102428A (en) * 1976-11-03 1978-07-25 Ensign-Bickford Company No-flash seismic cord

Also Published As

Publication number Publication date
GB1321526A (en) 1973-06-27
FR2114857A5 (de) 1972-06-30
PL81423B1 (de) 1975-08-30
SU464102A3 (ru) 1975-03-15
CS159294B2 (de) 1974-12-27
DE2057042B2 (de) 1973-10-25
BE775433A (fr) 1972-03-16
DE2057042A1 (de) 1972-05-31
DE2057042C3 (de) 1974-06-12

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