Shock insensitive initiating devices

• US 5,392,713 A
• Filed: 02/14/1994
• Issued: 02/28/1995
• Est. Priority Date: 02/14/1994
• Status: Expired due to Fees

• Current Assignee: United States of America Represented By Secretary of The Navy Chief of Naval Research Office of
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Brown, Jerry S., Conkling, John A.
• Primary Examiner(s): Nelson, Peter A.
• Application Number:
  US08/195,250
• Time in Patent Office: 379 Days
• Field of Search: 102/322, 102/275.11, 149/108.6
• US Class Current: 102/322
• CPC Class Codes: C06B 33/00 Compositions containing particulate metal, alloy, boron, silicon, selenium or tellurium with at least one oxygen supplying material which is either a metal oxide or a salt, organic or inorganic, capable of yielding a metal oxide
• CPC Class Codes: C06C 7/00 Non-electric detonators; Blasting caps; Primers
• CPC Class Codes: F42B 3/11 characterised by the material used, e.g. for initiator case or electric leads F42B3/107 takes precedence

Abstract

The invention relates to a shock insensitive explosive train initiating dce including a thin elongated metal casing containing a quantity of hydrated metal picrate therein, a thermite igniter composition disposed adjacent to the hydrated metal picrate charge and an ignition means selected from ignition means consisting of an electric match and a length of fuze cord. In a specific example, the hydrated metal picrate charge is barium picrate hydrate which may be disposed in an open (FIG. 1) or a sealed (FIG. 2) copper or aluminum casing. In the embodiment of FIG. 3, a tin/zinc alloy, protective, safety cover is disposed over a portion of the hydrated metal picrate. This safety cover has a low melting point (200° C.) and is adapted to melt in the event of a fire to thereby "unconfine" the hydrate metal picrate charge prior to it reaching explosion temperature of approximately 341° C.

Claims

1. A shock insensitive explosive initiating device comprising:

an elongated metal casing having an open end and a closed end;

a quantity of a hydrated metal picrate disposed within said elongated metal casing adjacent the closed end thereof;

an inert pressure plug disposed within said elongated metal casing and abutting said quantity of hydrated metal picrate;

a quantity of thermite igniter composition disposed within and adjacent said open end of said elongated metal casing;

said quantity of thermite igniter composition being in abutting relationship with said inert pressure plug and provided with an exposed surface;

an elongated heat generating fuze element having a first end embedded within said quantity of thermite igniter composition, a second end embedded within said hydrated metal picrate, and an intermediate portion extending through said inert pressure plug; and

ignition means disposed within said open end of said elongated metal casing and in abutting relationship with said thermite igniter composition.

2. The shock insensitive explosive initiating device of claim 1 wherein said elongated metal casing having a quantity of hydrated metal picrate disposed therein is a thin copper tube and said ignition means disposed in abutting relationship with said thermite igniter composition is selected from the group of ignition means consisting of an electric match and a flame producing fuze cord.

3. The shock insensitive explosive initiating device of claim 1 wherein said thermite igniter charge is a composition consisting of red iron oxide, silicon and boron composition in a 6:

1;

1 ratio, by weight.

4. The shock insensitive explosive initiating device of claim 1 wherein said elongated heat generating fuze element includes an extruded wire consisting of aluminum and palladium.

5. The shock insensitive explosive initiating device of claim 1 wherein said hydrated metal picrate is selected from the group of hydrated metal picrates consisting of barium picrate hydrate, calcium picrate hydrate, aluminum picrate hydrate, magnesium picrate hydrate, iron picrate hydrate and nickel picrate hydrate.

6. The shock insensitive explosive initiating device of claim 1 wherein said hydrated metal picrate is barium picrate hydrate.

7. A shock insensitive explosive initiating device comprising:

an elongated metal casing having a quantity of a hydrated metal picrate disposed therein;

a cup-shaped thermite igniter composition charge disposed around an end of said elongated metal casing and extending over a portion of the length of said elongated metal casing; and

ignition means disposed in abutting relationship with said thermite igniter composition charge.

8. The shock insensitive explosive initiating device of claim 7 wherein said hydrated metal picrate is barium picrate hydrate and said ignition means is selected from the group of ignition means consisting of a flame producing fuze cord length and an electric match.

9. The shock insensitive explosive initiating device of claim 7 wherein said cup-shaped thermite ignition charge consists of a 6:

1;

1 ratio, by weight, of red iron oxide, silicon and boron.

10. The shock insensitive explosive initiating device of claim 7 wherein said elongated metal casing having a quantity of a hydrated metal picrate disposed therein is provided with an open end and a closed end;

said hydrated metal picrate filling said closed end and extending from said open end of said elongated metal casing;

a cup-shaped metal casing disposed over and secured to said open end of said elongated metal casing and encasing said hydrated metal picrate extending from said open end of said elongated metal casing;

said thermite igniter composition charge being disposed around said closed end of said elongated metal casing;

said cup-shaped metal casing having a melting point substantially less than the ignition temperature of said hydrated metal picrate contained therein and in said elongated metal casing whereby, when exposed to a fire external to said shock insensitive explosive initiating device, said cup-shaped metal casing will melt and expose said hydrated metal picrate from confinement and thereby permit burning, while preventing explosion, of said hydrated metal picrate contained therein.

11. The shock insensitive explosive initiating device of claim 10 wherein said cup-shaped metal casing secured to said elongated metal casing is constructed of a tin/zinc alloy and has a melting point of approximately 200°

C.

12. The shock insensitive explosive initiating device of claim 11 wherein said hydrated metal picrate is barium picrate hydrate and has an ignition temperature of approximately 341°

C.

13. A shock insensitive explosive initiating device comprising:

an elongated first metal shell having an open end and a closed end and having a quantity of a hydrated metal picrate ignition charge disposed within said closed end and extending from said open end;

a second metal shell disposed over said open end of said first elongated first metal shell and encasing the portion of said hydrated metal picrate ignition charge extending therefrom;

a thermite igniter composition charge disposed over said closed of said elongated first metal; and

ignition means disposed in abutting relationship with said thermite igniter composition.

14. The shock insensitive explosive initiating device of claim 13 wherein said elongated first metal shell is formed of a metal selected from the group of metals consisting of copper and aluminum.

15. The shock insensitive explosive initiating device of claim 13 wherein said second metal shell has a melting point substantially below the explosion temperature of said hydrated metal picrate ignition charge.

16. The shock insensitive explosive initiating device of claim 15 wherein said second metal shell has a melting point of approximately 200°

C. and said hydrated metal picrate ignition charge is barium picrate hydrate having a combustion temperature of approximately 341°

C.

17. The shock insensitive explosive initiating device of claim 13 wherein said second metal shell is a 50:

50 tin/zinc alloy shell having a melting point of approximately 200°

C.

18. The shock insensitive explosive initiating device of claim 13 wherein said hydrated metal picrate ignition charge is selected from the group of hydrated metal picrate ignition charges consisting of barium picrate hydrate, calcium picrate hydrate, aluminum picrate hydrate, magnesium picrate hydrate, iron picrate hydrate and nickel picrate hydrate.

19. A shock insensitive explosive train initiating device comprising:

a thin elongated, metal casing;

a quantity of a hydrated metal picrate disposed within said thin elongated copper casing;

a thermite igniter composition disposed adjacent said quantity of a hydrated metal picrate;

ignition means disposed adjacent said thermite igniter composition whereby,

upon activation, said ignition means ignites said thermite igniter composition and said thermite igniter composition ignites said hydrated metal picrate.

20. The shock insensitive explosive train initiating device of claim 19 wherein said hydrated metal picrate is barium picrate hydrate;

said thermite igniter composition consists of a 6;

1;

1 ratio, by weight of red iron oxide, silicon and boron; and

said ignition means is selected from the group of ignition means consisting of an electric match and a flame producing fuze cord length.