US3407732A - Electrical detonator - Google Patents

Electrical detonator Download PDF

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Publication number
US3407732A
US3407732A US621536A US62153667A US3407732A US 3407732 A US3407732 A US 3407732A US 621536 A US621536 A US 621536A US 62153667 A US62153667 A US 62153667A US 3407732 A US3407732 A US 3407732A
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US
United States
Prior art keywords
detonators
ignition
detonator
current
delay
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
US621536A
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English (en)
Inventor
Przybylik Roza
Zalachowski Wiktor
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Individual
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Individual
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Filing date
Publication date
Priority claimed from PL113388A external-priority patent/PL58648B1/pl
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3407732A publication Critical patent/US3407732A/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
    • F42D—BLASTING
    • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
    • F42D1/04—Arrangements for ignition
    • F42D1/045—Arrangements for electric ignition
    • F42D1/05—Electric circuits for blasting
    • F42D1/055—Electric circuits for blasting specially adapted for firing multiple charges with a time delay
    • 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
    • F42B3/12—Bridge initiators
    • F42B3/124—Bridge initiators characterised by the configuration or material of the bridge

Definitions

  • Known electric'delayed action millisecond detonators give desired delays at firing, due to the location in the detoi'iatorshell of a'dela'y element, which is placed between the, ignition-headand the ignition .primary said de-. lay element being the'characteristicelement of detonators of this type.
  • Such delay element consists for-a tube filled with a retarding mass, which burns at a determined velocity.
  • the delay time from the moment of switching on of current to the moment of the detonation is usually adjusted by an adequate length of the tube with the retarding mass.
  • a delayed action detonator can be manufactured as a series by adjustment of lengths of the respective tubes.
  • the time intervals between detonators of a series are generally about 25 or or more milliseconds.
  • the smallest technically obtainable limit of interfire time between particular detonators of this type is about 20 milliseconds.
  • the detonator is constructed without separate delay elements and the retarding mass is pressed into the shell directly onto its ignition primer.
  • the delayed-action detonators of this type are not safe in methane and coal dust environment and so they are not fit for use in coal mining.
  • An object of the invention is the provision of a cheap and con-structionally simple delayed-action detonator.
  • the detonators according to the invention are not provided with special delay elements and their ignition heads contain the same. ignition mass for each delay time.
  • the desired delays are obtained by the application of ignition heads, provided with resistance wires of different thick-.
  • a current impulse causes an incandescence of the resistance wire which bridges the electrodes of the head and simultaneously ignites the head ignitionmass.
  • This impulse is called the ignition impulse and its magnitude to a high degree is dependent on the diameter of the resistance wire involved.
  • i current intensity (in this case of the current which fires the detonator)
  • t time of current passage from the moment of switching on of the detonator to the moment of ignition of the head (ignition time).
  • the ignition time is proportional to fourth power of resistance wire diameter and inversely proportional to the second power of current intensity.
  • the thicker the resistance wire the longer will be the ignition time of head and the reaction time of the whole detonator.
  • Such detonator series according to the invention may include an optional number of detonators practically (e.g., from a few to twenty) with diiferent delays, in which the firing delays of particular detonators are predetermined on the basis of the above formula.
  • the detonators according to the invention are to be connected in parallel.
  • parallel connection required careful wiring of shooting lines on account of the limited possibility of control of electric circuit resistance.
  • the delay time between the separate numbers, as well as the delay range of the whole detonator series can be optionally adjusted within large limits by changing the intensity of current, omitting some of the delay times, or by adding additional ones to the series.
  • the detonator of the invention can incorporate a wide variety of designs.
  • One such design which can be improved according to the invention appears in Sewerage and Sewage Treatment by Harold E. Babbitt, Sixth Edition, John Wiley & Sons, Inc., p. 183 (chapter entitled Construction of Sewers).
  • the detonaator may include a metal shell in which are loaded a sulphur filling layer 12.
  • Patented Qct. 29, 1958 3 a sulphur plug 14, an ignition charge 16, a priming charge 18 and a base charge 20.
  • Bridge 22 is located in ignition charge 16.
  • the bridge 22 consists of a plurality of wires of different diameter, wires 24 and 26 being illustrated by way of non-limitative example. These wires are connected in parallel with DC. source 28 via switch 30.
  • a selector switch 32 is provided to select the wire to be effective.
  • the drawing is illustrative only as various other structures can be employed to embody the improvements of the invention.
  • the invention also envisages a plurality of individual detonators each provided with a wire of different diameter, the detonators being used separately or being connected in parallel.
  • detonators according to the invention are their simple construction. Due to this fact, the manufacture of these detonators is easy and much cheaper than for those which contain conventional delay elements. Moreover, the possibility of obtaining very short intershoot time delays of millisecond order between the detonators is now possible according to the invention.
  • Detonation apparatus comprising ignition means and, in said means, a plurality of electrically conductive bridge. wires of different cross-sections to elfect dilferent delays.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Bags (AREA)
US621536A 1966-03-08 1967-03-08 Electrical detonator Expired - Lifetime US3407732A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PL113388A PL58648B1 (forum.php) 1966-03-08

Publications (1)

Publication Number Publication Date
US3407732A true US3407732A (en) 1968-10-29

Family

ID=19949443

Family Applications (1)

Application Number Title Priority Date Filing Date
US621536A Expired - Lifetime US3407732A (en) 1966-03-08 1967-03-08 Electrical detonator

Country Status (5)

Country Link
US (1) US3407732A (forum.php)
AT (1) AT268959B (forum.php)
BE (1) BE695205A (forum.php)
FR (1) FR1513137A (forum.php)
GB (1) GB1151156A (forum.php)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3974424A (en) * 1974-10-07 1976-08-10 Ici United States Inc. Variable resistance bridge element
US4239005A (en) * 1977-04-19 1980-12-16 Aktiebolaget Bofors Device for an electric igniter
EP0119458A3 (de) * 1983-03-11 1985-05-02 Hüls Troisdorf Aktiengesellschaft Elektrisches Zündmittel
EP0111195A3 (en) * 1982-12-14 1985-05-15 Rheinmetall Gmbh Gun ammunition, especially for high trajectory firing
FR2660749A1 (fr) * 1990-04-05 1991-10-11 Lacroix E Tous Artifices Systeme de declenchement sequentiel controle et automatique d'une pluralite de charges utiles pyrotechniques.
FR2740545A1 (fr) * 1995-10-30 1997-04-30 Livbag Snc Generateur pyrotechnique de gaz,a debit variable,pour coussins de protection
DE29810006U1 (de) 1998-06-04 1998-10-01 TRW Occupant Restraint Systems GmbH & Co. KG, 73553 Alfdorf Zünder für einen Gasgenerator
US10605576B1 (en) * 2017-10-16 2020-03-31 Reynolds Systems, Inc. Dual mode initiator system

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2918001A (en) * 1957-09-30 1959-12-22 William W Garber Radio-proof electric firing device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2918001A (en) * 1957-09-30 1959-12-22 William W Garber Radio-proof electric firing device

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3974424A (en) * 1974-10-07 1976-08-10 Ici United States Inc. Variable resistance bridge element
US4239005A (en) * 1977-04-19 1980-12-16 Aktiebolaget Bofors Device for an electric igniter
EP0111195A3 (en) * 1982-12-14 1985-05-15 Rheinmetall Gmbh Gun ammunition, especially for high trajectory firing
EP0119458A3 (de) * 1983-03-11 1985-05-02 Hüls Troisdorf Aktiengesellschaft Elektrisches Zündmittel
FR2660749A1 (fr) * 1990-04-05 1991-10-11 Lacroix E Tous Artifices Systeme de declenchement sequentiel controle et automatique d'une pluralite de charges utiles pyrotechniques.
FR2740545A1 (fr) * 1995-10-30 1997-04-30 Livbag Snc Generateur pyrotechnique de gaz,a debit variable,pour coussins de protection
WO1997016695A1 (fr) * 1995-10-30 1997-05-09 Livbag S.N.C. Generateur pyrotechnique de gaz, a debit adaptable, pour coussins de protection
US6079739A (en) * 1995-10-30 2000-06-27 Livbag S.N.C. Pyrotechnic gas generator with an adaptable flow rate for air bags
DE29810006U1 (de) 1998-06-04 1998-10-01 TRW Occupant Restraint Systems GmbH & Co. KG, 73553 Alfdorf Zünder für einen Gasgenerator
US6247409B1 (en) 1998-06-04 2001-06-19 Trw Occupant Restraint Systems Gmbh & Co., Kg Igniter for a gas generator
US10605576B1 (en) * 2017-10-16 2020-03-31 Reynolds Systems, Inc. Dual mode initiator system

Also Published As

Publication number Publication date
AT268959B (de) 1969-02-25
FR1513137A (fr) 1968-02-09
BE695205A (forum.php) 1967-08-14
GB1151156A (en) 1969-05-07

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