A detonator is an ignition device that is used for explosives , cartridge ammunition , bombs , grenades , mines , warheads and similar explosive devices in order to ignite the respective explosive. In their function, detonators are closely related to the fuse .
In military terms, a detonator is defined as an ammunition assembly that is intended to initiate an effective charge .
Modern explosives cannot normally be ignited simply by the action of heat; H. detonated, since a reliable detonation only occurs when a shock wave acts. Normal combustion of the explosive occurs when exposed to heat; this is an essential security feature.
A reliable ignition of modern explosives can therefore only be guaranteed by using a primer . Since detonators are much more sensitive to external influences, they are often stored and transported separately from the actual active agent and only inserted into the explosive charge immediately before they are used.
The actual ignition can take place in several stages; in this way a pre-charge can be ignited electrically, which ignites a booster charge, which in turn ignites the actual charge. The booster charge can also be arranged in such a way that the active charge is ignited at several points. The same can be achieved by using several detonators.
Furthermore, some weapon systems can contain several detonators, which detonate the active agent depending on the position.
The first detonators to trigger an explosive charge were fuses and fuses, which detonated the gunpowder charges common at that time (around the 10th century in China). This technique was also used in the first grenades filled with black powder . The grenadier ignited the fuse and threw the grenade, the same procedure was used when throwing grenades with throwing machines. When the first gunpowder guns appeared, the grenades were loaded, the fuse ignited and only then was the gun fired. However, it was quickly noticed that the propellant charge could trigger the igniter of the grenade. Pierced wooden tubes were used as detonators, the bore of which was filled with a slowly burning powder mixture, and which ensured reliable delay. These simple time fuses were quite suitable for siege guns. Around 1650 it was recognized that iron bombs were also useful in field artillery or as a mortar shell, especially if they were detonated in the air just above the target. In England, sticks filled with a slowly burning black powder mixture were developed, the length of which was known to burn for a long time. One was already able to determine the flight duration. The gunner cut the rods according to the duration of the flight. For handguns, ignition mechanisms were developed that were first used as matchlocks and later developed into flintlocks . This was state of the art up to the time of Napoleon; Attempts to detonate grenades with flint stones on impact were unsuccessful. With the invention of the percussion fuse, the first impact fuse made of wood was used around 1846. Metal detonators were only introduced by the British Navy after 1861. With the percussion lock , percussion caps became more common. They will be used as detonators for cartridge ammunition well into the 21st century.
A wide variety of detonators were developed for the different requirements.
The basic requirements for all detonators are operational and functional safety. Different detonators have been developed due to different functional requirements. The first use was the artillery , impact fuses were used. This showed that the detonators could have very different effects. When shooting in a forest, the grenades died at treetop height and showered the enemy with a hail of splinters. In the open field, the splinters scattered in a much smaller radius, but stones and earth were thrown at the enemy, who, however, was relatively safe when he was in a trench or cover hole. The trench is less useful in the forest because the splinters come from above. If the ground was very hard or if rock or concrete was shot, the grenade could simply burst without exploding. The first effect was used with shrapnel grenades , for this purpose time fuses were used . The shrapnel grenade is basically a container for oversized shotgun pellets, with the development of more explosive explosives, the HE grenade was developed. The high-explosive grenade could also be used against fortifications. Here, however, it was no longer desired to explode over the target, but to penetrate the target - the delay detonator was developed. Since the detonator on the grenade tip is destroyed when it hits armor before the tank has penetrated, the ground detonators or particularly hard bunker-breaking detonators were developed. This development was largely completed in the First World War. Air defense from the ground is a specialty of artillery. During the Second World War, high-flying planes were fought with HE shells. Due to the flight time of the projectile, the movement of the aircraft and the inaccuracies of the measurement technology, several guns were fired towards the target; the grenades exploded after the pre-calculated time lapse and should damage or destroy the aircraft by splinters or the pressure wave. Since it was found that aircraft were occasionally hit directly but not destroyed because the time fuse had not yet expired and the grenade simply passed through the target, the double fuse was developed. Double detonators act as time detonators and as highly sensitive impact detonators.
Another development was the electronic proximity detonator , which ignites when a predetermined distance to the target is reached.
Air defense systems : impact detonators ignite after a certain (maximum permissible) time in order to avoid losses and damage to the ground ( friendly fire ), as well as - as is more often found in older air defense systems such as the eight-eight gun - also with the largest possible To explode fragmentation effect close to the enemy flying object. Since direct hits are rare when fighting targets, the active electronic proximity detonators use the Doppler effect of a radio wave to determine the flyby situation. Other missiles use laser rangefinders (e.g. Mistral ) or a passive optical homing system guides so precisely that an impact fuse can be used ( Stinger ). Before the launch, a minimum flight time is calculated based on the differential speed and only then armed. In the event of failure to ignite or hit, anti-aircraft projectiles of any kind usually disassemble themselves after a maximum flight time in order not to pose a threat.
Security : All modern igniter of artillery shells and rockets meet the pipe and also the safe separation distance (the latter is also mask security called) by the igniter can address only at a certain distance from the gun or launch tube. This is usually achieved by using the swirl and the longitudinal acceleration as well as a downstream timer. Also has a Detonatorsicherung prevent before the end of the launch phase in accidental firing of the detonator of the bomb on the transfer charge can be ignited.
In sea mines , land mines or bombs , detonators are used, for example, according to the following functional principles:
- mechanical contact ( percussion fuse )
- Magnetic field ( magneto )
- Distance fuses
With chemical detonators, reactive substances are enclosed in different ampoules . After the ampoule is broken by impact or pressure, the contents combine with the release of heat and thus initiate the explosion. These so-called acid fuses are used, for example, for projectiles and mines.
Detonators ignite after breaking a line or the like (e.g. in the case of distress signals or hand grenades ).
Definition of terms
The detonator to distinguish are detonators and igniters : Civil explosive charges are fired mostly over detonators. The capsule is ignited either electrically or thermally using an ignition cord. The ignition of propellant charges or fuels is effected by a lighter. With cartridge ammunition it is called a primer . Only in the case of shotgun ammunition is the primer also referred to as a fuse .
- Hermann Kast: The explosives and explosives , Braunschweig, Vieweg, 1921
- ↑ Alfred Geibig: Explosive and scattering bodies, cutting and debris projectiles . In: The power of fire - serious fireworks of the 15th – 17th centuries Century in the mirror of its neuter tradition . Art collections of the Veste Coburg, Coburg 2012, ISBN 978-3-87472-089-2 , p. 177-226 .
- ↑ Hermann Kast: Die Spreng und Zündstoffe , page 402 ff.
- ^ Wilhelm Speisebecher: Pocket book for artillerymen. P. 103 no. 66, 2nd episode, Defense and Knowledge, Bonn 1974, ISBN 3-8033-0231-5 .
- ^ Rheinmetall: Waffentechnisches Taschenbuch. 5th edition 1980, p. 559.
- ^ Rheinmetall: Waffentechnisches Taschenbuch. Chapter detonator / Section 13.1., 5th edition 1980, p. 556.
- ^ Rheinmetall: Waffentechnisches Taschenbuch. Section 184.108.40.206. Safety systems , 5th edition 1980, p. 565ff.