US3699890A - Fire resistant photoflash cartridge - Google Patents

Abstract

A fire resistant photoflash cartridge containing a charge of photoflash composition and an electric primer for initiating ignition of said photoflash composition, the improvement comprising a disk of heating insulating material attached to said cartridge adjacent said electric primer and a heavy layer of intumescent material surrounding the remainder of the cartridge.

Description

[4 Oct. 24, 1972 FIRE RESISTANT PHOTOFLASH CARTRIDGE Primary Examiner-Benjamin A. Borchelt Assistant Examiner-James M. Hartley Attorney-R. S. Sciascia, H. H. Losche and Paul S.

[72] Inventor: James E. Short, Jr., Svv1tz City, Ind. Comgnon [73] Assignee: The United States of America as represented by the Secretary of the [57] ABSTRACT Navy A fire resistant photoflash cartridge containing a [22] Filed: May 4, 1971 charge of photoflash composition and an electric primer for initiating ignition of said photoflash com- [21] Appl' 140083 position, the improvement comprising a disk of heating insulating material attached to said cartridge ad- [52] US. Cl. ..102/37.8, 102/374, l02/37.6, jacent said electric primer and a heavy layer of intu- 102/105 mescent material surrounding the remainder of the [51] Int. Cl. ..C06d 1/10, C06d l/04 cartridge. [58] Field of Search.......l02/32, 35, 35.6, 37.4, 37.6, l02/37.7, 37.8, 66, 70, 87, 92.2, 92.6, 102, I03. 105

[56] References Cited 2 Qlaims, 2 Drawing Figures UNITED STATES PATENTS 3,399,621 9/1968 Schillreff ..l02/37.8

2 L) 18 /5j \E/Z/ X Q A ,4 I2 71 PATENTEDUBI 24 1912 Fig.2

INVENTOR. JAMES E. SHOR7, JR

Gaul s.

ATTORNEYS STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefore.

BACKGROUND OF THE INVENTION The present invention relates to a flare cartridge for providing illumination in support of night aerial photography, and more particularly to a flare cartridge which is insulated to delay ignition in the event of a fire in the area where the cartridge is stored or located.

The military services are presently using a photoflash cartridge which, after a fixed delay, explodes to provide a high intensity flash. One such device is shown and described in US. Pat. No. 3,473,472, which issued Oct. 21, 1969, to Billy R. Bliss, Clarence W. Gilliam, and John E. Laswell. In this patent there is shown and described a photoflash cartridge which, upon ejection and after a fixed delay, explodes to provide a high intensity, short duration flash. An inner charge case is propelled or fired from a cartridge case and, after a fixed delay, a homogeneous explosive mixture is ignited that causes the inner charge case to explode and the surrounding flash composition to be rapidly ignited.

Photoflash cartridges which are presently used by the military services are reliable and provide good light output, however, these photoflash cartridges have an inherent weakness. In recent fires aboard ships it has been learned that photoflash cartridges are one of the first pyrotechnic items to be ejected or exploded by the heat of the fire. In tests conducted at the Naval Ammunition Depot, Crane, Indiana, it has been shown that in the event of a fire caused by ignition of jet fuel, photoflash cartridges mounted beneath an aircraft wing are likely to eject and explode in about 26 seconds after the jet fuel was ignited. Thus in about rminute after a fire starts involving an aircraft carrying photoflash cartridges, a fireman is susceptible to being hit by an ejected or exploded cartridge.

SUMMARY OF THE INVENTION The present invention relates to a photoflash cartridge which is insulated so that the cartridge will withstand a burning jet fuel environment for a minimum of minutes. The photoflash cartridge is provided with a closed end that has an electric primer positioned therein and a. disk of heat insulating material is attached to the closed end. The remainder of the cartridge is covered with a heavy layer of intumescent vinyl material which is applied in thin layers to build up to a thickness of about of an inch.

BRIEF DESCRIPTION OF THE DRAWING F IG. 1 is a top view of a preferred embodiment of the present invention; and

FIG. 2 is a side view, partially broken away, of a preferred embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, there is shown a Billy R. Bliss, Clarence W. Gilliam, and John E. Laswell. A cartridge case 11 is substantially closed on one end which is provided with a threaded hole so that an electric primer 12 can be threadedly connected therein. The opposite end of cartridge case 11 is open. The closed end of cartridge case 11 is provided with a counterbore that is filled with an expelling charge 13, such as black powder. A photoflash composition 14 is contained within case 15 and a closing disk 16 is provided to close the end of case 15. Cap 17 is provided to close the outer end of cartridge case 1 1.

A disk 18 of heat insulating material is attached to the closed end of cartridge case 1 l and is provided with holes 21,22 and 23, which are provided so that electrical contact can be made to ignite primer 12. By way of example, disk 18 might be made of grade AAA-H R asbestos-filled phenolic, which is sold commercially by Raybestos-Manhattan, lnc., Bridgeport, Conn., and attached to said case by cementing. The remainder of cartridge case ll is covered with a heavy layer of intumescent material 24. By way of example, the intumescent material 24 might be Albi-89, an intumescent vinyl material marketed by the Albi Mfg. Dept. Cities Service Co., Rockville, Conn. The coating of Albi-89 material is applied in thin layers which are builtup to provide a coating having a thickness of about of an inch. It has been observed in tests conducted at Naval Ammunition Depot, Crane, Indiana, that a photoflash cartridge having a disk 18 attached thereto and a inch layer of intumescent material will not explode or ignite for at least 7 minutes after exposure to a burning jet fuel environment.

I claim:

1. A fire resistant photoflash cartridge comprising:

a cartridge case having a closed end and an open end,

a charge of photoflash composition in said cartridge case,

a cap closing the open end of said cartridge case,

an electric primer threadedly attached in said closed end of said cartridge case,

a disk of asbestos-filled phenolic material attached to the closed end of said cartridge case, said disk having at least two holes therein for providing passage for electrical conductors for carrying a current to said primer, and

a heavy layer of intumescent vinyl material covering said cap and the remainder of said cartridge case not covered by said disk of asbestos-filled phenolic material.

2. A fire resistant photoflash cartridge as set forth in claim 1 wherein said disk of asbestos-filled phenolic material is attached to said closed end of said cartridge case by cementing.

Claims (2)

1. A fire resistant photoflash cartridge comprising: a cartridge case having a closed end and an open end, a charge of photoflash composition in said cartridge case, a cap closing the open end of said cartridge case, an electric primer threadedly attached in said closed end of said cartridge case, a disk of asbestos-filled phenolic material attached to the closed end of said cartridge case, said disk having at least two holes therein for providing passage for electrical conductors for carrying a current to said primer, and a heavy layer of intumescent vinyl material covering said cap and the remainder of said cartridge case not covered by said disk of asbestos-filled phenolic material.

2. A fire resistant photoflash cartridge as set forth in claim 1 wherein said disk of asbestos-filled phenolic material is attached to said closed end of said cartridge case by cementing.

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