US2700336A - Blasting cartridge and initiator therefor - Google Patents

Blasting cartridge and initiator therefor Download PDF

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Publication number
US2700336A
US2700336A US278392A US27839252A US2700336A US 2700336 A US2700336 A US 2700336A US 278392 A US278392 A US 278392A US 27839252 A US27839252 A US 27839252A US 2700336 A US2700336 A US 2700336A
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US
United States
Prior art keywords
charge
blackpowder
blasting
blasting cartridge
initiator
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 - Lifetime
Application number
US278392A
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English (en)
Inventor
Sillitto George Percy
James B Howat
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.)
Imperial Chemical Industries Ltd
Original Assignee
Imperial Chemical Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Imperial Chemical Industries Ltd filed Critical Imperial Chemical Industries Ltd
Application granted granted Critical
Publication of US2700336A publication Critical patent/US2700336A/en
Anticipated expiration legal-status Critical
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B3/00—Blasting cartridges, i.e. case and explosive
    • F42B3/04—Blasting cartridges, i.e. case and explosive for producing gas under pressure
    • F42B3/06—Blasting cartridges, i.e. case and explosive for producing gas under pressure with re-utilisable case
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B3/00—Blasting cartridges, i.e. case and explosive
    • F42B3/10—Initiators therefor

Definitions

  • the present invention relates to improvements in or relating to blasting cartridges and to initiators therefor.
  • the invention is particularly concerned with blasting cartridges wherein the blasting charge comprises a mixture comprising an alkali metal nitrite and an ammonium salt of an inorganic acid and capable of self-sustained gas-producing decomposition on local heating which is contained in a rigid casing having a tiring head and a venting head, wherein said ring head is provided with means for transmission of electric energy from without to initiating means within the casing capable of initiating the chemical reaction of the charge and wherein said venting head is separated from the body of the casing by a member adapted to yield under a predetermined pressure.
  • a blasting cartridge of the aforesaid kind is employed for the blasting of coal in fiery and dusty mines since the decomposition of the charge occurs entirely without flame.
  • the gentle heaving action obtained and its exceptional freedom from the liability to ignite methane/ air or coal dust/ air mixtures render it particularly suitable for use in coal mining operations.
  • the said initiating means usually consists of an electric powder fuse, comprising a small charge of blackpowder fired by an electric fusehead.
  • an appreciable time is required for the decomposition once initiated to progress through the entire blasting charge. This delay may be as much as one second and5may vary somewhat in successive shots and while for single shot blasting operations this is of little or no importance for simultaneous shot tiring it is desirable considerably to reduce the variability of the time required for the propagation of the decomposition.
  • the initiating means comprises an electric fusehead and a charge of blackpowder located near one end of the container by including in the initiating means a second charge of blackpowder in the vicinity of the other end of said container and a length of instantaneous fuse having its textiles reproof positioned for ignition at one end by said electric fusehead and extending to said second charge of blackpowder.
  • a blasting cartridge wherein the blasting charge comprises a mixture comprising an alkali metal nitrite and an ammonium salt of an inorganic acid and capable of self-sustained gas-producing decomposition on local heating which is contained in a rigid casing having a tiring head and a venting head, wherein said firing head is provided with means for transmission of electrical energy from without to initiating means within the casing capable of initiating the chemical reaction of the charge, wherein said venting head is separated from the body of the casing by a member adapted to yield under a predetermined pressure, and wherein the initiating means comprises an electric fusehead and a charge of blackpowder located near one end of the container is characterised in that the initiating means includes a second charge of blackpowder in the vicinity of the other end of said container and a length of instantaneous fuse having its textiles reproof positioned for ignition at one end by said electric fusehead and extending to said second charge of blackpowder.
  • the length of said instantaneous fuse between the two charges of blackpowder is preferably such that the length f 2,700,336 ce Patented Jan. 25, 1955 of the casing occupied by the initiating means is substantially the same as that occupied by the main charge of the cartridge.
  • An initiator comprises an electric fusehead, means for transmission of electrical energy from without to said electric fusehead, a primary charge of blackpowder positioned for firing by said electric fusehead, a length of instantaneous fuse, the textile content of which is ireproof, also positioned for ring by said electric fusehead, and a secondary blackpowder charge positioned at the remote end of said instantaneous fuse for firing thereby.
  • the main charge consisting of a mixture of an alkali metal nitrite with one or more ammonium salts such that the charge is capable of undergoing a self-sustained gasproducing decomposition also preferably includes a mildly alkaline stabiliser and preferably consists of an equimolecular mixture of sodium nitrite and ammonium chloride including from l to 3% of its weight of anhydrous sodium carbonate or magnesium oxide as stabiliser.
  • the two blackpowder charges are preferably of the order of 110 grains and it is also preferred that the burning speed of the second blackpowder charge should be slightly greater than that of the primary charge so that both charges are consumed at substantially the same time'.
  • FIG. 1 shows a longitudinal section of a blasting cartridge in accordance with the invention and Fig. 2 shows a longitudinal section of the initiator shown in outline in Fig. 1.
  • 1 is a high tensile steel container
  • 2 is a venting head
  • 3 is a mild steel disc adapted to yield at a predetermined pressure of the order of 15 tons per square inch
  • 4 is a ring head
  • 5 is .
  • 6 is a positive terminal
  • 7 is a gasket
  • 8 is a negative terminal
  • 9 is a positive terminal ball contact maker
  • 10 is a flanged copper ring
  • 11 is a reproofed cardboard cylinder containing the iirst blackpowder charge 18 which consists of 90 grains of blackpowder
  • 12 is a wooden plug
  • 13 is a copper sleeve
  • 14 is a metal liap bent into the copper sleeve 13 to form
  • the cartridge is posined 1n the normal manner and a tiring current passed through the leads connected to the terminals 6 and 8.
  • This ignites the fusehead 16 which in turn ignites the blackpowder charge 18 and the instantaneous fuse 22 which latter simultaneously ignites the slightly faster burning blackpowder charge 27.
  • the two blackpowder charges 18 and 27, which are consumed at substantially the same time, effect simultaneously commencement of the decomposition of the main charge at two widely separated points.
  • Using this type initiator results in the period between application of the firing current and the bursting of the bursting disc being reduced to the order of 20-50 milliseconds, whereas the initiators hitherto available this period is of the order of 0.1-1 second.
  • This reduction in time enables the initiators of the present invention to be used to fire a number of shots simultaneously, for example, by positioning a number of cartridges such as that illustrated, connecting these electrically in series or parallel and applying a tiring current.
  • An initiator for use in a blasting cartridge wherein the blasting Charge ⁇ comprises a mixture comprising an alkali metal nitrite andfau 'ammonium salt'of an inorganic'acid,which mixture is capable of self-sustained, gas-producing decomposition on local heating and is contained in a rigid casing having a firing head and a venting head, said'ring head being provided with means for transmission ⁇ of electrical energy from without to initiating means within' the Asaid casing capable of initiating the chemical'reaction of the charge, ⁇ and Said venting head being separated from the body of the said casing by a member adapted to yield under a predetermined pressure,
  • an electric fusehead comprising an electric fusehead, means for transmission of electrical energy lfrom without to said electric fusehead, a primary Charge 0f blackpowder Positioned for. ring by said electric fusehead, a lengthof'instantaneous fuse, the textile content of which is waterproof, also positioned for firing by said fusehead and a secondary blackpowder charge positioned at the remote end of said instantaneous fuseforY ring thereby.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Bags (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
US278392A 1951-05-11 1952-03-25 Blasting cartridge and initiator therefor Expired - Lifetime US2700336A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB11130/51A GB695908A (en) 1951-05-11 1951-05-11 Improvements in or relating to blasting cartridges and initiators therefor

Publications (1)

Publication Number Publication Date
US2700336A true US2700336A (en) 1955-01-25

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ID=9980589

Family Applications (1)

Application Number Title Priority Date Filing Date
US278392A Expired - Lifetime US2700336A (en) 1951-05-11 1952-03-25 Blasting cartridge and initiator therefor

Country Status (5)

Country Link
US (1) US2700336A (ru)
BE (1) BE511319A (ru)
DE (1) DE947143C (ru)
FR (1) FR1066087A (ru)
GB (1) GB695908A (ru)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2916993A (en) * 1953-11-06 1959-12-15 Ici Ltd Blasting device
US2926565A (en) * 1958-03-10 1960-03-01 Rudolph B Thorness Safety explosive line cutter
EP0033610A2 (en) * 1980-02-04 1981-08-12 Morton Thiokol, Inc. Igniter for use in a pyrotechnic gas generator for inflating gas bags, and gas generator incorporating such an igniter
US6467387B1 (en) * 2000-08-25 2002-10-22 Schlumberger Technology Corporation Apparatus and method for propelling a data sensing apparatus into a subsurface formation

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2942547A (en) * 1958-06-24 1960-06-28 Olin Mathieson Gas generating assembly

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US676219A (en) * 1899-03-24 1901-06-11 Caleb F Bryant Blasting device.
US2190460A (en) * 1935-08-21 1940-02-13 Ici Ltd Blasting charge

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US676219A (en) * 1899-03-24 1901-06-11 Caleb F Bryant Blasting device.
US2190460A (en) * 1935-08-21 1940-02-13 Ici Ltd Blasting charge

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2916993A (en) * 1953-11-06 1959-12-15 Ici Ltd Blasting device
US2926565A (en) * 1958-03-10 1960-03-01 Rudolph B Thorness Safety explosive line cutter
EP0033610A2 (en) * 1980-02-04 1981-08-12 Morton Thiokol, Inc. Igniter for use in a pyrotechnic gas generator for inflating gas bags, and gas generator incorporating such an igniter
EP0033610A3 (en) * 1980-02-04 1982-02-17 Thiokol Corporation Igniter for use in a pyrotechnic gas generator for inflating gas bags, and gas generator incorporating such an igniter
US4358998A (en) * 1980-02-04 1982-11-16 Thiokol Corporation Igniter for a pyrotechnic gas bag inflator
US6467387B1 (en) * 2000-08-25 2002-10-22 Schlumberger Technology Corporation Apparatus and method for propelling a data sensing apparatus into a subsurface formation

Also Published As

Publication number Publication date
FR1066087A (fr) 1954-06-02
BE511319A (ru)
DE947143C (de) 1956-08-09
GB695908A (en) 1953-08-19

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