US2927498A - Electric detonators - Google Patents

Electric detonators Download PDF

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Publication number
US2927498A
US2927498A US674507A US67450757A US2927498A US 2927498 A US2927498 A US 2927498A US 674507 A US674507 A US 674507A US 67450757 A US67450757 A US 67450757A US 2927498 A US2927498 A US 2927498A
Authority
US
United States
Prior art keywords
thermoplastic
case
bridge plug
plug
ring
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
US674507A
Other languages
English (en)
Inventor
Melvin E Eilers
Lester E Smith
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.)
Olin Corp
Original Assignee
Olin Corp
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
Priority to BE569577D priority Critical patent/BE569577A/xx
Application filed by Olin Corp filed Critical Olin Corp
Priority to US674507A priority patent/US2927498A/en
Priority to GB23578/58A priority patent/GB892020A/en
Priority to DEO6275A priority patent/DE1062597B/de
Priority to FR1200592D priority patent/FR1200592A/fr
Application granted granted Critical
Publication of US2927498A publication Critical patent/US2927498A/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
    • F42B3/10—Initiators therefor
    • F42B3/103—Mounting initiator heads in initiators; Sealing-plugs
    • 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
    • F42B3/125—Bridge initiators characterised by the configuration of the bridge initiator case

Definitions

  • Electric detonators usually consist of an explosive train housed in a metal cup provided with a bridge wire imbedded in a sensitive explosive material within the case.
  • the bridgewire isextended between the ends of two lead wires which are supported by' the bridge plug closing the mouth of the case. Morerecently, the, metal detonator case has been replaced with oneformed from an organic thermoplastic material, and the bridge plug is also formed of an organic thermoplastic material.
  • thermoplastic 1 case and plug are particularly well exemplified'in U.S. Patents 2,415,045 and 2,420,201 granted to FrederickjR. Seavey. While the detonators described in these. patents represent a pronounced advance in the field, there is still a definite need' for thermoplastic encased detonators, having positive waterproof seals that can be provided with case on a commercial scale.
  • an obect of this invention to provide an ,electric blasting cap provided with an'improved closure that overcomes the disadvantages and diflicultiesof I previously known detonators.
  • Anothenobject'of this in vention is to provide anoveldetonator housed in anor'ganic' thermoplastic material.
  • a further object of this invention is to provide anew and'n'ovel method of sealing felectric'idetohators.
  • Still anotherobject is to provide a method of sealing electric detonators housed in difiicult ly soluble or practically insoluble thermoplastic material.
  • FIG. 2 is a sectional view of another embodiment ,of a bridge plug made in accordance with this invention.
  • figure 1 is a sectional view of a bridgeplug made in .
  • Figure 3 is a sectional longitudinal view of an' assem bled detonator in position preparatory to sealing;
  • Figure 4 is a sectional longitudinal view of an electric detonator representing a'jpreferr'ed embodiment of this invention..-
  • the sealing of an electric detonator in accordance with this invention is accomplished by placing a metal ring about the periphery of a thermoplastic bridge plug intermediate its ends, inserting the bridge plug with the 7 ring about it into the mouth of a detonator case provided with an explosive charge and placing the assembly in a high frequency energy field whereby the metallic ring is heated by an induced current. plastic material surrounding the metallic ring to melt and fusetogether so as to form a positive seal for the deto- This causes the thermo-.
  • the-metallic ring must be in contact with the bridge plug aswell as the case.
  • the bridge plug In practice, it has been most convenient to provide the bridge plug with a circumferential groove to accommodate the metallic ring.
  • the loop or ring of metal can be'formed of foil or wire wrapped about the bridge plug.
  • the ring can be cast and imbedded in'the periphery of the bridge plug. This ismost readily accomplished by molding the bridge .plug with the metallic ring as an insert between the ends of the plug.
  • the ring can be in the form of a metallic band, foil, or a metallic suspension, such as a metallic paint, on the interior of the case wall or on the side wall of the case. In any event, the metallic ring must be continuous so as to form a non-interrupted loop aboutthe bridge plug..
  • the heating effect of the current induced into the metal ring is more pronounced when the ring is formed of a high resistance metallic material such as iron or Nichrome (60% nickel, 25% iron, and 15% chromium) and the like. Materials having lowerelectrical resistances can be used with equal success but require high energy output to provide the same heating effect.
  • a high resistance metallic material such as iron or Nichrome (60% nickel, 25% iron, and 15% chromium) and the like. Materials having lowerelectrical resistances can be used with equal success but require high energy output to provide the same heating effect.
  • the metallic ring between the bridge plug and case is utilized as a secondary coil which generates sufficient heat to cause the thermoplastic material about it tomelt and commingle to effect a seal.
  • the current is induced in the metallic ring by positioning the assembled d etona'tor in the high frequency field of the work coil of an induction heating generator.
  • the detonator is positioned withinthe coil and preferably'near its center so as'to avoid uneven heating of the metallic ring.'
  • the amount of energy imparted to themetal ring can be controlled within close limits by variation of a number of factors.
  • the degree of heating can be controlled by variations in the distance between the work coil and the man ring, the number of'turns in the work coil, the cross'sec- V tional area and position ofthe metal ring,"the power-output of the work coil, and the duration of time rdr'app1ication of the energy.
  • it is 'pi'e ferred to shuntthe ends of the lead wires so as to prevent circuit of the detonator. s p
  • FIG. 1 arid-Z show are different types of bridge plugsthat can'be us'e'd in carrythe formation of a secondary current through 'thejtir inig ing outthe present invention.
  • bridge plug 1 is formed of molded ethyl cellulose and carries a pair of lead wires 2 insulated in sheaths 3 of ethylc ellu lose, the lower ends of the lead wires being connected by bridge ,wire 4.
  • the bridge plug is also provided'with an annular steel ring 5 about its periphery.
  • The-plug was made in accordance with standard moldingprocedures with'the steel ring forming a metal insert. -It will be noted that the outer face of the ring 5 isflush with the lateral surface of the bridge plug.
  • v v v j Figure 2 represents a modified type of bridge plug utilized in carrying out this invention.
  • the steel ring has been replaced by two turns of 30 gauge iron wire 6 positioned within the peripheral groove 7 of the bridge plug.
  • the external diameter of the coiled iron wire is substantially the same as the diameter of the bridge plug.
  • the bridge plug of Figure l is shown positioned in the open end of an ethylcellulose detonator case 8 which may be loaded with any suitable explosive train shown generally at 9.
  • the bridge plug 1 forms a slidingfit with the internal surface of the detonator case and the steel ring 5 is also in contact with the interior surface of the detonator case.
  • the assembled detonator is positioned in the center of an induction heating gens erator work coil shown diagrammatically at 10.
  • Detonators assembled in the manner shown in Figure 3 were sealed by placing them in the center of the work coil and maintaining the coil at an energy level of about 1 kilowatt for 2 seconds.
  • the current thus induced in the steel ring heated it sufiiciently to melt, fuse, and
  • FIG. 4 illustrates an assembled plasti c electric detonator that has been sealed in accordance with thisprocess. It will be noted that the ethylcellulose immediatelyabout the steel ring 5 has fused together as shown generally at 11 so as to merge the plug and case into a composite unit.
  • electric detonator is used herein in its broadest sense and includes electric squibs, electric'blasting caps and other types of electrically actuated explosive igniters and initiators.
  • a method of sealing a substantially cylindrical electric detonator having a thermoplastic case and a substantially cylindrical thermoplastic bridge plug which comprises providing a thermoplastic bridge plug with a peripheral groove intermediate the ends of the plug, substantially filling said groove with an annular metallic member, inserting the plug and the metallic member into i the open end of the thermoplastic case containing an explosive charge with the annular metallic member contacting the thermoplastic case and being separated from the explosive charge by a, substantial portion of the bridge plug, and elevating the temperature of the metallic member above the melting point of the thermoplastic components of the detonator by an induced electric current whereby the thermoplastic material of the bridge plug and the thermoplastic material of the case adjacent the annular metallic member melts and intermingles to form an autogenous Weld between the bridge plug and the case.
  • a method ofsealing a substantially cylindrical electric detonator having a thermoplastic case and a thermoplastic bridge plug with a pair of lead wires passing therethrough which comprises providing a substantially cylindrical thermoplastic bridge plug having a metal ring molded in a groove about the periphery of the plug intermediate its ends, inserting the bridge plug intothe open end of a thermoplastic detonator' case containing an ex plosive charge and positioning the metal ring in contact with the thermoplastic case, the metal ring being separated from the explosive charge by a substantial portion of the plug, and elevatingrthe temperature of the ring current.
  • thermoplastic materials can be used.
  • polyvinyl chloride polyvinyl acetate, polyvinyl chloride-acetate,

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Bags (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
US674507A 1957-07-26 1957-07-26 Electric detonators Expired - Lifetime US2927498A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE569577D BE569577A (en(2012)) 1957-07-26
US674507A US2927498A (en) 1957-07-26 1957-07-26 Electric detonators
GB23578/58A GB892020A (en) 1957-07-26 1958-07-22 Electric detonators
DEO6275A DE1062597B (de) 1957-07-26 1958-07-22 Verfahren zur Abdichtung einer elektrischen Sprengkapsel
FR1200592D FR1200592A (fr) 1957-07-26 1958-07-22 Détonateurs électriques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US674507A US2927498A (en) 1957-07-26 1957-07-26 Electric detonators

Publications (1)

Publication Number Publication Date
US2927498A true US2927498A (en) 1960-03-08

Family

ID=24706880

Family Applications (1)

Application Number Title Priority Date Filing Date
US674507A Expired - Lifetime US2927498A (en) 1957-07-26 1957-07-26 Electric detonators

Country Status (5)

Country Link
US (1) US2927498A (en(2012))
BE (1) BE569577A (en(2012))
DE (1) DE1062597B (en(2012))
FR (1) FR1200592A (en(2012))
GB (1) GB892020A (en(2012))

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL9001603A (nl) * 1989-08-01 1993-07-01 Buck Chem Tech Werke Werkwijze voor het aangeven van de ontsteking van een oefen-grondmijn en een inrichting voor het uitvoeren van de werkwijze.
EP0704348A1 (de) * 1994-10-01 1996-04-03 TEMIC Bayern-Chemie Airbag GmbH Anzündeinheit für einen Gasgenerator eines passiven Rückhaltesystems
US10012245B2 (en) * 2014-09-09 2018-07-03 Arianegroup Sas Pyrotechnic actuator
USD1025276S1 (en) * 2020-08-05 2024-04-30 Liaoning Qingyang Explosive Materials Co., Ltd Detonator base

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1276156B (de) * 1963-04-17 1968-08-29 Amp Inc Treibladungs-Presswerkzeug zum Verbinden einer Klemme mit einem elektrischen Leiter
DE29810008U1 (de) 1998-06-04 1998-10-01 TRW Occupant Restraint Systems GmbH & Co. KG, 73553 Alfdorf Zünder für einen Gasgenerator

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB652054A (en) * 1948-03-25 1951-04-18 British Mechanical Prod Ltd A new or improved method of securing two interfitting parts together and/or of obtaining a seal between two interfitting connected parts
US2722155A (en) * 1950-11-01 1955-11-01 Olin Mathieson Manufacture of electric blasting caps
US2757566A (en) * 1953-02-26 1956-08-07 Canadian Ind 1954 Ltd Delay electric blasting caps containing spiral delay elements
US2767655A (en) * 1953-06-15 1956-10-23 Olin Mathieson Blasting caps
US2802422A (en) * 1953-11-09 1957-08-13 Hercules Powder Co Ltd Static resistance electric initiator
US2802421A (en) * 1953-11-09 1957-08-13 Hercules Powder Co Ltd Static resistant electric initiator
US2818020A (en) * 1955-11-17 1957-12-31 Glenn A Burklund Safeguarded electric firing initiating devices

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB652054A (en) * 1948-03-25 1951-04-18 British Mechanical Prod Ltd A new or improved method of securing two interfitting parts together and/or of obtaining a seal between two interfitting connected parts
US2722155A (en) * 1950-11-01 1955-11-01 Olin Mathieson Manufacture of electric blasting caps
US2757566A (en) * 1953-02-26 1956-08-07 Canadian Ind 1954 Ltd Delay electric blasting caps containing spiral delay elements
US2767655A (en) * 1953-06-15 1956-10-23 Olin Mathieson Blasting caps
US2802422A (en) * 1953-11-09 1957-08-13 Hercules Powder Co Ltd Static resistance electric initiator
US2802421A (en) * 1953-11-09 1957-08-13 Hercules Powder Co Ltd Static resistant electric initiator
US2818020A (en) * 1955-11-17 1957-12-31 Glenn A Burklund Safeguarded electric firing initiating devices

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL9001603A (nl) * 1989-08-01 1993-07-01 Buck Chem Tech Werke Werkwijze voor het aangeven van de ontsteking van een oefen-grondmijn en een inrichting voor het uitvoeren van de werkwijze.
EP0704348A1 (de) * 1994-10-01 1996-04-03 TEMIC Bayern-Chemie Airbag GmbH Anzündeinheit für einen Gasgenerator eines passiven Rückhaltesystems
US5634660A (en) * 1994-10-01 1997-06-03 Temic Bayern-Chemie Airbag Gmbh Gas generator ignition unit for a passive restraint system
US10012245B2 (en) * 2014-09-09 2018-07-03 Arianegroup Sas Pyrotechnic actuator
USD1025276S1 (en) * 2020-08-05 2024-04-30 Liaoning Qingyang Explosive Materials Co., Ltd Detonator base

Also Published As

Publication number Publication date
DE1062597B (de) 1959-07-30
FR1200592A (fr) 1959-12-22
BE569577A (en(2012))
GB892020A (en) 1962-03-21

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