US3430566A - Marine seismic detonator - Google Patents

Marine seismic detonator Download PDF

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Publication number
US3430566A
US3430566A US618413A US3430566DA US3430566A US 3430566 A US3430566 A US 3430566A US 618413 A US618413 A US 618413A US 3430566D A US3430566D A US 3430566DA US 3430566 A US3430566 A US 3430566A
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US
United States
Prior art keywords
detonator
water
casing
aperture
layer
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
US618413A
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English (en)
Inventor
Edward Mervyn Patterson
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
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Publication of US3430566A publication Critical patent/US3430566A/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
    • F42B3/10—Initiators therefor
    • F42B3/192—Initiators therefor designed for neutralisation on contact with water
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
    • G01V1/02—Generating seismic energy
    • G01V1/04—Details
    • G01V1/06—Ignition devices

Definitions

  • a seismic detonator which had an aperture in the casing sealed with a plug of water-destructible resilient material extending through the aperture.
  • the plug resisted the ingress of water for a period to allow the detonator to be fired but was eventually destroyed by the water to allow the explosive charges to be desensitised.
  • the preferred plug was a moulded plug of watersoluble thermoplastic material located in the mouth end of the casing around the electrical leading wires. This plug has not proved to be ideally suitable because the time required for the disarming of the detonator could not be sufliciently well controlled.
  • a detonator which was disarmalble by immersion in water has also been proposed in United States Patent 1,901,469 for use in coal mines.
  • This detonator had a perforated casing wherein the perforations were closed by a film of gelatine.
  • This type of closure is not, however, satisfactory for a marine seismic detonator because a film made from a colloid which has been completely dissolved and dried is permeated by water only very slowly. If the film is made sufficiently thin to allow a sufficient rate of water permeation, it is mechanically weak and ruptures, thus allowing the detonator to be destroyed immediately on immersion in water before the normal tiring can take place.
  • a seismic detonator suitable for marine use has its electric fusehead and explosive charges enclosed within a casing having an aperture obturated with particulate water-gellable colloid.
  • the detonator casing has one or more apertures in the normally blind end of the detonator casing which contains the explosive charges, and the, or each, aperture is covered with a layer of particulate watergellable colloid, the explosive charges being positioned in the casing above said colloid.
  • suitable water-gellable colloid examples include gela tine, polyvinyl alcohol, maleic anhydride/vinyl copolymer, and water-soluble cellulose ethers.
  • the water-soluble cellulose ethers such as, for example, sodium carboxymethyl cellulose (SCMC) and methyl cellulose 'are especially advantageous because of the ability of granules of the material to bind together when pressed into the detonator casing.
  • the size of the particles of water-gellable colloid may vary over a wide range but colloids of average particle size in the range 16 to 60 b.s.s. are convenient and are easily loaded into the usual size of detonator casing.
  • the detonator of the invention When the detonator of the invention is immersed in water, the granules of the gellable materials which come into contact with the water become swollen and gelled and the resulting gel retards further water penetration, thus providing a delay period during which the detonator can be fired reliably.
  • the water continues to permeate the layer of gel and eventually sufficient water penetrates to the explosive charges and the fusehead to disarm the detonator.
  • the rate permeation increases with increasing water pressure so that any detonator which sinks is disarmed at an increased rate in proportion to the depth of immersion.
  • the gelled layer is relatiely weak and deformable under hydrostatic pressure so that a sunken detonator will be disarmed more quickly under hydrostatic pres sures which are sufficiently high to deform the gelled layer.
  • the disarming time can be controlled by variation of several factors including the aperture size and the chemical and physical nature of the obturating water-gellable material. For example, the layer thickness, viscosity and degree of pressing of the water-gellable material covering the aperture all affect the disarming time.
  • detonator which includes further features of the invention, will now be described, byway of example only, with reference to the single figure of the accompanying drawing which shows a longitudinal section of the detonator.
  • the detonator comprises an elongated cylindrical tubular casing 11 of an aluminium/manganese alloy having a circular aperture 12 in its end 13.
  • the casing end 13 contains a layer of particulate water-gellable material 14 immediately over the aperture 12, a base charge 15 of pentaerythritol tetranitrate (PETN) and a priming charge 16 of lead azide, all the contents being consolidated by pressing.
  • PETN pentaerythritol tetranitrate
  • An electric fusehead 17 comprising a bridgewire heating element 18 embedded in a matchhead of defiagrating composition 19 and connected to two insulated connecting wires 20, is located within the casing 11.
  • the wires 20 extend through a mouth end of the casing 11 and are located therein by a neoprene plug 21 around which a portion of the mouth end of the casing is firmly crimped.
  • the detonator casing 11 had an internal diameter of 0.25 in., the base charge was 0.8 g. PETN, the firing charge was 0.15 g. lead azide priming composition and the aperture 12 was 0.03 in. in diameter.
  • the details of the layer of water-gellable material 14 and the performance of the detonators when immersed in water at a depth of 8 feet are given in the accompanying Table 1.
  • the particle size of the water-gellable material was 16-60 b.s.s. in all cases.
  • a seismic detonator for marine use comprising a casing containing an electric fusehead and an explosive charge and having an aperture therethrough obturated with water-permeable time-delay sealing means for permitting permeation of water into said casing after a period of immersion and having a water-permeation rate which increases with an increase in Water pressure, said sealing means including a porous layer of pressed particulate water-gellable colloid obturating said aperture, the particles of said layer being consolidated as a result of being pressed, said layer being sufliciently thick and sufficiently pressed to prevent immediate ingress of water upon imlose ether.
  • a detonator as claimed in claim 2 wherein the watergellable colloid comprises sodium carboxymethyl cellulose or methyl cellulose.
  • a detonator as in claim 1 wherein said detonator casing has a normally blind end containing the explosive charge, said normally blind end having at least one aperture therethrough, said particles of water-gellable colloid being consolidated in the form of a layer which is positioned in the casing between said explosive charge and said aperture.

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  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Acoustics & Sound (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing Of Micro-Capsules (AREA)
  • Prevention Of Electric Corrosion (AREA)
  • Air Bags (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
US618413A 1966-03-18 1967-02-24 Marine seismic detonator Expired - Lifetime US3430566A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB11988/66A GB1119168A (en) 1966-03-18 1966-03-18 Marine seismic detonator

Publications (1)

Publication Number Publication Date
US3430566A true US3430566A (en) 1969-03-04

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ID=9996370

Family Applications (1)

Application Number Title Priority Date Filing Date
US618413A Expired - Lifetime US3430566A (en) 1966-03-18 1967-02-24 Marine seismic detonator

Country Status (9)

Country Link
US (1) US3430566A (no)
AT (1) AT265936B (no)
BE (1) BE695344A (no)
DE (1) DE1289770B (no)
ES (1) ES338141A1 (no)
FR (1) FR1515427A (no)
GB (1) GB1119168A (no)
NL (1) NL147256B (no)
NO (1) NO116537B (no)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3631802A (en) * 1967-10-17 1972-01-04 Atlas Chem Ind Detonator comprising n-nitro-n-methylglucamine pentanitrate
US3945320A (en) * 1973-07-04 1976-03-23 Imperial Chemical Industries Limited Water-resistant fuse-cord
US5070788A (en) * 1990-07-10 1991-12-10 J. V. Carisella Methods and apparatus for disarming and arming explosive detonators
US20050150714A1 (en) * 2003-08-26 2005-07-14 Michael Raleigh Non-explosive acoustic source
PL131379U1 (pl) * 2023-04-04 2024-10-07 Wojskowy Instytut Techniczny Uzbrojenia Zapalnik elektryczny

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4484960A (en) * 1983-02-25 1984-11-27 E. I. Du Pont De Nemours And Company High-temperature-stable ignition powder

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3279372A (en) * 1964-06-04 1966-10-18 Ici Ltd Seismic detonator
US3322066A (en) * 1966-02-08 1967-05-30 Trojan Powder Co Self-destructive explosive cartridge for underwater seismic exploration

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE22418C (de) * M. VON FÖRSTER, Prem.-Lieut. a. D. in Berlin W.; Zietenstr. 13 Verfahren zum Sprengen mit komprimirter Schiefsbaumwolle unter Wasser

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3279372A (en) * 1964-06-04 1966-10-18 Ici Ltd Seismic detonator
US3322066A (en) * 1966-02-08 1967-05-30 Trojan Powder Co Self-destructive explosive cartridge for underwater seismic exploration

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3631802A (en) * 1967-10-17 1972-01-04 Atlas Chem Ind Detonator comprising n-nitro-n-methylglucamine pentanitrate
US3945320A (en) * 1973-07-04 1976-03-23 Imperial Chemical Industries Limited Water-resistant fuse-cord
US5070788A (en) * 1990-07-10 1991-12-10 J. V. Carisella Methods and apparatus for disarming and arming explosive detonators
US20050150714A1 (en) * 2003-08-26 2005-07-14 Michael Raleigh Non-explosive acoustic source
US7028807B2 (en) * 2003-08-26 2006-04-18 Bae Systems Advanced Technologies, Inc. Non-explosive acoustic source
PL131379U1 (pl) * 2023-04-04 2024-10-07 Wojskowy Instytut Techniczny Uzbrojenia Zapalnik elektryczny

Also Published As

Publication number Publication date
AT265936B (de) 1968-10-25
NL6702992A (no) 1967-09-19
FR1515427A (fr) 1968-03-01
NO116537B (no) 1969-04-08
BE695344A (no) 1967-09-11
GB1119168A (en) 1968-07-10
ES338141A1 (es) 1968-04-01
NL147256B (nl) 1975-09-15
DE1289770B (de) 1969-02-20

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