Shock tube detonator

A shock tube detonator is a non-electric explosive fuze or initiator in the form of small-diameter hollow plastic tubing used to transport an initiating signal to an explosive charge by means of a percussive wave traveling the length of the tube.[1] It is a linear signal transmission installation that is designed to be used as disseminating an energetic signal through shock tube to a detonator. Shock tube is a hollow extruded tube containing a thin layer of energetic materials upon its inner diameter. Once it is initiated, the shock tube transfers a signal to a detonating output charge, characteristically incorporating an instantaneous output or a pre-determined delay. Shock Tube Detonator is available with an optional patented in-line initiator consisting of a threaded adapter and a pre-installed percussion primer providing convenient and reliable initiation.

It was invented by Per Anders Persson of Nitro Nobel AB, patented,[2] and sold by them under the registered trademark Nonel,[3] containing a small quantity of high explosive, but safer and more reliable than detonating cord with the same quantity of explosive.[2] Another early product contained an enclosed combusting, non-detonating fiber.[4]

The most common product is 3 mm outer diameter and 1 mm inner diameter, with a tiny dusting of HMX/aluminum explosive powder on the tubing's inner surface, which detonates down the tube at a speed greater than 6500 feet per second but does not burst the tube.[5] Being non-electrical and non-metallic, shock tubes are less sensitive to static electricity and radio frequency energy and thus have replaced many uses of electric detonators and are safer to handle and store than detonating cord. A version containing an explosive gas mixture has the additional advantage of being entirely inert until the tubing is charged with the gas.[5]

One manufacturer estimates that over 2 billion feet of shock tube are used each year worldwide, in commercial blasting, military demolition, theatrical special effects, automobile airbags, aircraft escape systems, IED initiation and professional fireworks.[1]

References

  1. "All About Shock Tube". Archived from the original on 9 February 2010. Retrieved 13 November 2017.
  2. US patent 3590739, Persson, Per-Anders (Sodertalje, Sweden) assigned to Nitro-Nobel AB, "FUSE", issued 1971-7-6
  3. James T. Thurman, ‘’Practical bomb scene investigation’‘, p104
  4. US patent 4220087, Posson, Philip L Assigned to Explosive Technology, Inc. (Fairfield, Calif. ), "Linear ignition fuse", issued 1980-9-2
  5. Rontey, Daniel. "All About Shock Tube: A Review". Archived from the original on 1 November 2010. Retrieved 13 Nov 2017.


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