US2487317A - Explosive cartridge for plaster shooting - Google Patents

Explosive cartridge for plaster shooting Download PDF

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Publication number
US2487317A
US2487317A US625699A US62569945A US2487317A US 2487317 A US2487317 A US 2487317A US 625699 A US625699 A US 625699A US 62569945 A US62569945 A US 62569945A US 2487317 A US2487317 A US 2487317A
Authority
US
United States
Prior art keywords
plaster
cartridge
explosive
shooting
primer
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
US625699A
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English (en)
Inventor
Davidson Samuel Henry
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 US2487317A publication Critical patent/US2487317A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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

Definitions

  • the present invention relates to the provision of blasting explosive cartridges for plaster shoot- For the purpose of breaking boulders into smaller fragments of more convenient size for removal, the operation known as plaster shooting, or mud-caping is often carried out.
  • a cylindrical cartridge of a detonating explosive which is frequently of the same nature as the explosives used for bore-hole shooting in quarry blasting.
  • a detonator inserted at its end in the usual way, is pressed with its cylindrical surface along an incipient crack in the boulder, and the cartridge is stemmed by the application of a considerable thickness of clay, mud, sand or the like materials, which should be free from stones, and is then fired.
  • the plaster shot blasting cartridges provided according to the present invention enable stemming to be dispensed with altogether and are adapted to ensure that the explosive will achieve a high velocity of detonation before any considerable amount of it has detonated at low velocity, a result not ordinarily attained with hitherto used plaster shooting assemblies.
  • a plaster shot blasting cartridge comprises a cylindrical plastic, that is to say permanently deformable: explosive charge capable of developing high velocity detonation at one end of which there is positioned a rigid tubular structure surrounding a high velocity detonation primer in detonation contact with said explosive charge and adapted to receive a commercial detonator at its free end, the said plastic explosive charge, high velocity detonation primer and rigid tubular structure being enclosed in a wrapper of easily rupturable material.
  • the operator using the plaster shot cartridge holds it with the tubular rigid structure as a hand grip and squashes the other end of the cartridge on to the desired portion of the surface of 2 the boulder with suillcient force to rupture the wrapper and flatten out that end of the cylinder of plastic explosive.
  • Thedetonator which may belprovided with a suitable length of fuze if it is not an electric detonator, is then inserted into the high velocity primer, and the charge is then ready for firing.
  • the squashing of the end of the cy der of plastic explosive presented to the bo der increases the area of contact substantially; beyond the original cross section of the cylinder and thus ensures the transmission of much of the energy of the explosive to the material of the boulder, and normally causes it to adhere enough to permit of the use of the cartridge on sloping surfaces.
  • the fact that the rigid tubular structure containing the high velocity primer still projects from the surface of the more or less flattened mass of explosive facing the operator's hand also ensures that the detonation' wave will be well developed in a direction favourable to the fragmentation of the boulder, and that a high velocity of detonation will rapidly be attained.
  • Ezplosives of high power capable of detonating at high velocities when initiated by means of commercial detonators in tampered boreholes may advantageously be used, so long as they are of the requisite permanently deformable plasticity,
  • Plastic explosives based on solutions of nitrocellulose in liquid nitric esters may advantagequsly be used, and many of the available high strength nitroglycerine-nitrocellulose plastic explosives of commerce are very suitable, for instance various gelignites of from about per cent of the strength of Blasting Gelatine upwards, and Polar Ammon gelatine dynamite.
  • Various plastic explosives comprising solutions of nitrocellulose liquid aromatic nitrocompounds are also suitable.
  • the high velocity detonation primer comprises desirably about an ounce of an explosive capable of being detonated at high velocity by'a commercial detonator without confinement, for instance a pressed guncotton tetryl or trinitrotoluene pellet, or a cast Pentolite primer.
  • the primer is provided with a recess or channel accessible from the end of the cartridge remote from that to be applied to the boulder, for the purpose of receiving the detonator, which may conveniently be an ordinary detonator attached to the end of a length of safety fuze.
  • Figs. 1 and 2 arerespectively a longitudinal section and a section along AA of Figure 1 of a plaster shot blasting cartridge according to the invention
  • Figs. 3 and 4 are respectively a longitudinal section and a section along BB of Fig. 3 of the same plaster shot blast- 3 ing cartridge after it has been squashed against a boulder to be blasted.
  • I is a rigid hollow wooden cylindrical structure adapted to serve as a hand grip.
  • 2 is a high velocity detonation primer, consisting of a one ounce compressed trinitrotoluene pellet, 4
  • i is a plastic blasting explosive charge of Polar Ammon gelatine dynamite in juxtaposition with and separated from the rigid structure I and the primer 2 by a thin waxed paper septum i. iswaxed paper surrounding the hand grip I and the plastic blasting charge I and folded at the top of the high velocity detonation primer 2 and at the bottom of the explosive charge 5.
  • the waxed paper I is perforated at l, a little above the base of the explosive charge 5.
  • 3 is a layer of colored aper stuck to the wax paper to indicate the 'end of the plaster shot blasting cartridge which the detonator is to be inserted.
  • a plaster shot blasting cartridge which comprises a cylindrical permanently deformable plastic explosive charge capable 01' developing high velocity detonation. a high velocity detonation primer adapted at one end to receive a commercial detonator and placed in detonation contact at its other end with the said explosive charge, a rig-id tubular structure surrounding said primer, and a wrapper of easily rupturable material enclosing said plastic explosive charge, said primer, and said rigid tubular structure.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Drilling And Exploitation, And Mining Machines And Methods (AREA)
  • Pressure Welding/Diffusion-Bonding (AREA)
US625699A 1945-02-09 1945-10-31 Explosive cartridge for plaster shooting Expired - Lifetime US2487317A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3277/45A GB588326A (en) 1945-02-09 1945-02-09 Improvements in or relating to explosive cartridges for plaster shooting

Publications (1)

Publication Number Publication Date
US2487317A true US2487317A (en) 1949-11-08

Family

ID=9755294

Family Applications (1)

Application Number Title Priority Date Filing Date
US625699A Expired - Lifetime US2487317A (en) 1945-02-09 1945-10-31 Explosive cartridge for plaster shooting

Country Status (5)

Country Link
US (1) US2487317A (no)
BE (1) BE462635A (no)
FR (1) FR919289A (no)
GB (1) GB588326A (no)
LU (1) LU27862A1 (no)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2698575A (en) * 1949-07-02 1955-01-04 Inst Of Inventive Res Charge for seismic exploration
US2764939A (en) * 1952-12-22 1956-10-02 American Cyanamid Co Explosive package
US2913982A (en) * 1952-12-29 1959-11-24 Hercules Powder Co Ltd Priming device
CN109708547A (zh) * 2019-01-18 2019-05-03 中国矿业大学(北京) 一种露天矿山预裂爆破装药装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US196767A (en) * 1877-11-06 Improvement in blasting-cartridges
US273270A (en) * 1883-03-06 Primer for blasting-cartridges

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US196767A (en) * 1877-11-06 Improvement in blasting-cartridges
US273270A (en) * 1883-03-06 Primer for blasting-cartridges

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2698575A (en) * 1949-07-02 1955-01-04 Inst Of Inventive Res Charge for seismic exploration
US2764939A (en) * 1952-12-22 1956-10-02 American Cyanamid Co Explosive package
US2913982A (en) * 1952-12-29 1959-11-24 Hercules Powder Co Ltd Priming device
CN109708547A (zh) * 2019-01-18 2019-05-03 中国矿业大学(北京) 一种露天矿山预裂爆破装药装置

Also Published As

Publication number Publication date
GB588326A (en) 1947-05-20
LU27862A1 (no)
BE462635A (no)
FR919289A (fr) 1947-03-04

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