Pyrotechnic train

• US 5,090,322 A
• Filed: 06/22/1987
• Issued: 02/25/1992
• Est. Priority Date: 06/25/1986
• Status: Expired due to Term

• Current Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Original Assignee: Secretary of State of Defence In Her Britannic Majesty's Government of The United Kingdom of Great Britian and Northern Ireland
• Inventors: Allford, Frederick G.
• Primary Examiner(s): Nelson, Peter A.
• Application Number:
  US07/068,675
• Time in Patent Office: 1,709 Days
• Field of Search: 149/14, 149/15, 102/202.5, 102/202.7, 156/634, 156/82
• US Class Current: 102/202.7
• CPC Class Codes: C06B 45/14 a layer or zone containing an inorganic explosive or an inorganic explosive or an inorganic thermic component
• CPC Class Codes: C06C 5/00 Fuses, e.g. fuse cords
• CPC Class Codes: C23C 14/06 characterised by the coating material C23C14/0021 , C23C14/04 take precedence
• CPC Class Codes: F42B 3/16 Pyrotechnic delay initiators F42B3/195 takes precedence; programmable electronic delay initiators F42C11/065

Abstract

A micro pyrotechnic train is formed from a reactive laminate comprised by a plurality of thin films of an electron acceptor material (9) and an electron donor material (10) alternately layered upon a substrate layer by vacuum deposition. The thus deposited films are then removed from selected areas by etching, using standard printed circuit board techniques, to leave a desired network of reaction progression paths (2). The thickness of the films is of substantially molecular order to maximize molecular intermingling between them, and the number of films is selected to ensure a reliable burning characteristic. Ignition of the conjoint films at any selected location initiates a self-sustaining exothermic reaction which progresses laterally along the film interfaces.

In further aspects the reactive laminate is applicable as an infra-red emitting coating and as a flash transmitter. It is also applicable as a bridge igniter, the laminate being employed as an electrode bridge in place of a conventional exploding bridge wire.

Claims

1. A pyrotechnic train including a reactive laminate comprised by a substrate layer of an electron acceptor material having vapour-deposited thereon a film of an electron donor material, the said two materials being conjointly capable of exothermic reaction when subjected to heat.

2. A pyrotechnic train as claimed in claim 1 including a further plurality of films of the two said materials, each one sequentially vapour-deposited upon the previously deposited film in alternating sequence.

3. A pyrotechnic train as claimed in claim 2 further including at least one interlayered film of a moderating material.

4. A pyrotechnic train as claimed in claim 2 wherein the thickness of each film is of substantially molecular order.

5. A pyrotechnic train as claimed in claim 1 wherein the electron acceptor material is polytetrafluoroethylene and the electron donor material is magnesium.

6. A pyrotechnic train as claimed in claim 2 wherein the electron donor material is lead oxide and the electron acceptor material is titanium.

7. A pyrotechnic train as claimed in claim 5 comprising a flash transmitting cord having an annulus of vapour-deposited magnesium extending coaxially between an inner core and an outer sleeve, both of polytetrafluoroethylene.

8. A pyrotechnic train as claimed in claim 1 arranged as a bridge between two electrodes located adjacent a detonator charge.

9. A method of manufacture for a pyrotechnic train as claimed in claim 1 wherein a desired configuration of reaction progression paths is provided by the removal of unwanted regions of the deposited film from the substrate layer by a process of selective etching.

10. A method of manufacture for a pyrotechnic train as claimed in claim 1 wherein the substrate layer is selectively masked prior to deposition so as to deposit the film in a desired configuration of reaction progression paths.