Shock tube detonator
Encyclopedia
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. It was invented by Per Anders Persson of Nitro Nobel AB, patented, and sold by them under the registered trademark Nonel
, containing a small quantity of high explosive, but safer and more reliable than detonating cord
with the same quantity of explosive. Another early product contained an enclosed combusting, non-detonating fiber.
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. 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.
One manufacturer estimates that over 2 billion feet of shock tube are used each year worldwide, in commercial blasting, military demolition
, theatrical special effect
s, automobile airbags, aircraft escape systems and professional fireworks
.
Fuse (explosives)
In an explosive, pyrotechnic device or military munition, a fuse is the part of the device that initiates function. In common usage, the word fuse is used indiscriminately...
or initiator
Pyrotechnic initiator
A pyrotechnic initiator is a device containing a pyrotechnic composition used primarily to ignite other, more difficult-to-ignite materials, e.g. thermites, gas generators, and solid-fuel rockets...
in the form of small-diameter hollow plastic tubing
Tube (fluid conveyance)
A tube, or tubing, is a long hollow cylinder used to convey fluids .The terms "pipe" and "tube" are almost interchangeable, although minor distinctions exist — generally, a tube has tighter engineering requirements than a pipe. Both pipe and tube imply a level of rigidity and permanence,...
used to transport an initiating signal to an explosive charge by means of a percussive wave
Shock wave
A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...
traveling the length of the tube. It was invented by Per Anders Persson of Nitro Nobel AB, patented, and sold by them under the registered trademark Nonel
Nonel
Nonel is a shock tube detonator designed to initiate explosions, generally for the purpose of demolition of buildings and for use in the blasting of rock in mines and quarries. Instead of electric wires, a hollow plastic tube delivers the firing impulse to the detonator, making it immune to most of...
, containing a small quantity of high explosive, but safer and more reliable than detonating cord
Detonating cord
Detonating cord is a thin, flexible plastic tube filled with PETN . With the PETN exploding at a rate of approximately 4 miles per second, any common length of det cord appears to explode instantaneously...
with the same quantity of explosive. Another early product contained an enclosed combusting, non-detonating fiber.
The most common product is 3 mm outer diameter and 1 mm inner diameter, with a tiny dusting of HMX
HMX
HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the name has been variously listed as High Melting eXplosive, Her Majesty's eXplosive, High-velocity Military eXplosive, or High-Molecular-weight rdX.The molecular...
/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. Being non-electrical and non-metallic, shock tubes are less sensitive to static electricity
Static electricity
Static electricity refers to the build-up of electric charge on the surface of objects. The static charges remain on an object until they either bleed off to ground or are quickly neutralized by a discharge. Static electricity can be contrasted with current electricity, which can be delivered...
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
Gas explosion
A gas explosion is an explosion resulting from a gas leak in the presence of an ignition source. The principal explosive gases are natural gas, methane, propane and butane, because they are widely used for heating purposes. However, many other gases like hydrogen, are combustible and have caused...
has the additional advantage of being entirely inert until the tubing is charged with the gas.
One manufacturer estimates that over 2 billion feet of shock tube are used each year worldwide, in commercial blasting, military demolition
Demolition
Demolition is the tearing-down of buildings and other structures, the opposite of construction. Demolition contrasts with deconstruction, which involves taking a building apart while carefully preserving valuable elements for re-use....
, theatrical special effect
Special effect
The illusions used in the film, television, theatre, or entertainment industries to simulate the imagined events in a story are traditionally called special effects ....
s, automobile airbags, aircraft escape systems and professional fireworks
Fireworks
Fireworks are a class of explosive pyrotechnic devices used for aesthetic and entertainment purposes. The most common use of a firework is as part of a fireworks display. A fireworks event is a display of the effects produced by firework devices...
.