US3667992A - Fulminating material application technique - Google Patents

Fulminating material application technique Download PDF

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Publication number
US3667992A
US3667992A US83135A US3667992DA US3667992A US 3667992 A US3667992 A US 3667992A US 83135 A US83135 A US 83135A US 3667992D A US3667992D A US 3667992DA US 3667992 A US3667992 A US 3667992A
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US
United States
Prior art keywords
wire
chlorate
coating
fulminating material
anvil
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
US83135A
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English (en)
Inventor
Stephen V Brown
Thomas B Mcdonough
John W Shaffer
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.)
GTE Sylvania Inc
Original Assignee
Sylvania Electric Products Inc
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 Sylvania Electric Products Inc filed Critical Sylvania Electric Products Inc
Application granted granted Critical
Publication of US3667992A publication Critical patent/US3667992A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K5/00—Light sources using charges of combustible material, e.g. illuminating flash devices
    • F21K5/02—Light sources using charges of combustible material, e.g. illuminating flash devices ignited in a non-disrupting container, e.g. photo-flash bulb
    • F21K5/023—Ignition devices in photo flash bulbs
    • F21K5/026—Ignition devices in photo flash bulbs using mechanical firing, e.g. percussion of a fulminating charge

Definitions

  • the invention relates to the manufacture of photofiash lamps and more particularly to those of the percussive type.
  • a percussive-type photofiash lamp comprises an hermetically sealed, light-transmitting envelope containing a source of actinic light and having a primer secured thereto. More particularly, the percussivetype photofiash lamp comprises a length of glass tubing constricted to a tip at one end thereof and having a primer sealed therein at the other end thereof.
  • the length of glass tubing which defines the lamp envelope contains a combustible, such as shredded zirconium foil, and a combustion supporting gas, such as oxygen.
  • the primer comprises a metal tube and a charge of fulminating material on a wire anvil supported therein. Operation of the lamp is initiated by an impact onto the tube of the primer to cause deflagration of the fulminating material on the wire anvil up through the tube to ignite the combustible disposed in the lamp envelope.
  • percussive fiashlamps The requirements that must be met by a fulminating material for percussive fiashlamps are unique and differ appreciably from those for the filament-initiated paste used in battery operated flashlamps. These differences arise primarily from the percussive mode of initiation and the extreme mechanical sensitivity required therefor.
  • the ignition paste In battery operated flashlamps, the ignition paste is heated by a wire filament until ignition occurs. Energy input to the paste extends over a period of one or more milliseconds.
  • energy input to the fulminating material of a percussive flashlamp is in the form of a single nearly instantaneous impact, the duration of which would be measured in microseconds.
  • the impact energy available is severely limited by mechanical size restrictions, the necessity for vibration-free operation, and the need to synchronize the lamp with the operation of a delicate and precise camera shutter mechanism. Accordingly, the fulminating material for percussive flashlamps must be extremely sensitive. This necessary sensitivity has been achieved by the use of an intimate mixture of red phosphorus and potassium chlorate along with a finely powdered metal such as titanium.
  • Ignition pastes for conventional filament type flashlamps use nitrocellulose as a binding resin, and organic solvents such as amyl acetate as the vehicle.
  • organic solvents such as amyl acetate
  • water was evaluated as the vehicle in conjunction with water soluble binding resins such as hydroxyethyl cellulose.
  • the fulminating material deposited from such an aqueous suspension was found to be much more sensi- 3,667,992 Patented June 6, 1972 "ice tive to impact than a similar material deposited from organic solvents. This enhanced sensitivity was attributed to deposition of the potassium chlorate onto the particles of red phosphorus, resulting in a more intimate mixture.
  • the principal object of this invention is to provide a method of applying fulminating material on the primer anvil wire of a percussive type photofiash lamp which is safe and economical for large scale production and at the same time provides an impact sensitivity such that the fiashlamps will have a high degree of ignition reliability and photometric performance.
  • Sodium chlorate is not generally used in impact sensitive mixtures because it absorbs moisture which results in deactivation. It can be used to advantage in the fulminating material for percussive flashlamps, however, due to the hermetically sealed structure of such lamps.
  • the anvil is first dipped into an aqueous slurry having the following dried composition: titanium, 70.49%; red
  • the burning behavior of the dried residue prepared as described above varies greatly with the concentration of sodium chlorate used. Below about by weight sodium chlorate in the dip solution, impact sensitivity falls off rapidly. A saturated solution containing about 52% sodium chlorate by weight may be used but the resulting coating burns violently and results in a decreased light output from the flashlamp.
  • Other chlorate salts of high solubility e.g. soluble to the extent of or greater by weight in Water
  • calcium chlorate, lithium chlorate, magnesium chlorate, aluminum chlorate, and zinc chlorate may be used, for example calcium chlorate, lithium chlorate, magnesium chlorate, aluminum chlorate, and zinc chlorate.
  • the extreme deliquescence of these materials may render their use in flashlamps more diificult with regard to drying and maintaining the coating dry prior to hermetic closure of the fiashlamp.
  • phosphorus sesquisulfide may be used in place of red phosphorus, if desired, although a slight loss in sensitivity may be noted.
  • the single figure is a sectional elevational view of a percussive-type photoflash lamp having a primer of the type with which the method of this invention may be employed.
  • the lamp comprises a length of glass tubing defining an hermetically sealed lamp envelope 2 constricted at one end to define an exhaust tip 4 and shaped to define a seal 6 about a primer 8 at the other end thereof.
  • the primer 8 comprises a metal tube 10 and a wire anvil 12 coated with a charge of fulminating material 14.
  • a combustible such as filamentary zirconium 16 and a combustion-supporting gas such as oxygen are disposed within the lamp envelope.
  • the wire anvil 12 is centered within the tube 10 and held in place by a crimp 18 just above the head 20 on the anvil. Additional means, such as lobes 22 on wire anvil 12, are also used to aid in stabilizing and supporting it substantially coaxial Within the primer tube 10 and insuring clearance between the fulminating material 14 and the inside wall of the tube 10.
  • chlorate salt solution is an aqueous solution containing at least 15% by weight of dissolved chlorate salt.
  • chlorate salt solution is an aqueous solution containing not less than 10% and not more than 52% by weight of dissolved sodium chlorate.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Paints Or Removers (AREA)
  • Dental Preparations (AREA)
US83135A 1970-10-22 1970-10-22 Fulminating material application technique Expired - Lifetime US3667992A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US8313570A 1970-10-22 1970-10-22

Publications (1)

Publication Number Publication Date
US3667992A true US3667992A (en) 1972-06-06

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Application Number Title Priority Date Filing Date
US83135A Expired - Lifetime US3667992A (en) 1970-10-22 1970-10-22 Fulminating material application technique

Country Status (6)

Country Link
US (1) US3667992A (enrdf_load_stackoverflow)
JP (1) JPS5636521B1 (enrdf_load_stackoverflow)
AU (1) AU3462371A (enrdf_load_stackoverflow)
CA (1) CA963660A (enrdf_load_stackoverflow)
GB (1) GB1306308A (enrdf_load_stackoverflow)
ZA (1) ZA717057B (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3724990A (en) * 1971-11-15 1973-04-03 Gen Electric Photoflash lamp
US3734679A (en) * 1970-11-20 1973-05-22 T Mcdonough Photoflash lamp
US3893798A (en) * 1972-12-15 1975-07-08 Gen Electric Photoflash lamp
US4065546A (en) * 1973-12-05 1977-12-27 Ethyl Corporation Process for preparing halophosphazene mixtures
US4244295A (en) * 1979-01-10 1981-01-13 Gte Products Corporation Radiant energy activated pyrotechnic cap having desiccant therein
US4263850A (en) * 1979-01-10 1981-04-28 Gte Products Corporation Pyrotechnic cap with moisture indicator
US4267774A (en) * 1979-01-10 1981-05-19 Gte Products Corporation Heat-sealed pyrotechnic cap
EP2664602A3 (en) * 2012-05-14 2014-10-01 UPL Limited Coated particulate phosphorus, compositions and products containing the same and preparation methods

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3734679A (en) * 1970-11-20 1973-05-22 T Mcdonough Photoflash lamp
US3724990A (en) * 1971-11-15 1973-04-03 Gen Electric Photoflash lamp
US3893798A (en) * 1972-12-15 1975-07-08 Gen Electric Photoflash lamp
US4065546A (en) * 1973-12-05 1977-12-27 Ethyl Corporation Process for preparing halophosphazene mixtures
US4244295A (en) * 1979-01-10 1981-01-13 Gte Products Corporation Radiant energy activated pyrotechnic cap having desiccant therein
US4263850A (en) * 1979-01-10 1981-04-28 Gte Products Corporation Pyrotechnic cap with moisture indicator
US4267774A (en) * 1979-01-10 1981-05-19 Gte Products Corporation Heat-sealed pyrotechnic cap
EP2664602A3 (en) * 2012-05-14 2014-10-01 UPL Limited Coated particulate phosphorus, compositions and products containing the same and preparation methods

Also Published As

Publication number Publication date
GB1306308A (enrdf_load_stackoverflow) 1973-02-07
JPS5636521B1 (enrdf_load_stackoverflow) 1981-08-25
CA963660A (en) 1975-03-04
ZA717057B (en) 1972-07-26
AU3462371A (en) 1973-04-19

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