Fuse
A fuse is a burning cord which is used to trigger a pyrotechnic charge or an explosive charge after a defined period of time. The various fuses and fuses belong to the kind of ignition means .
The correct term for the fuse is actually fuse or safety fuse. Under lighting is the production of a burn-up , under firing , however, the triggering of a detonation . Therefore, no explosives can be ignited with a fuse, but pyrotechnic charges or detonators containing an initial charge can. Only the explosive fuse, the detonating cord , detonated.
use
Fuses are attached to many over-the-counter fireworks . The fuses are firmly connected to the pyrotechnic charge of the fireworks and represent a delay that allows the igniter to create the necessary safety distance before the actual pyrotechnic effect (usually initially the ejector or propellant charge) ignites.
Also propelling charges of model rockets can be ignited by means of fuses. However, the fuses are not rigidly connected to the propellant. They are inserted into the propellant through the nozzle and fixed with a match .
The primary use, however, is enticing in large commercial fireworks , where individual effects are combined to form whole groups that only require one ignition point. With the advent of electric detonators ( blasting and wired Exploding bridge to drive), which will allow, each effect individually in tenths of seconds, enticing importance lost, and is used primarily for the many special effects that compiles a pyrotechnician itself from commercial products.
Lighting means
Wildfire
The term wildfire used to mean burning a trail of powder. It is the historical form of all modern fuses. The term refers to the speed at which the powder burns and the flame makes its way. With uncovered burn-off, this is in the centimeter range per second. This is where the proverb `` something spreads like wildfire ' ' comes from the similar form of fire , which refers to the rapid spread of news and news.
Fuse
The fuse was originally a slowly smoldering rope that was nitrided for this purpose , for example by boiling in a saltpetre solution . These were used to fire muzzle-loading rifles and cannons .
Other Luntentypen consist of a black powder - core which is sheathed with one to three plies leimgetränktem tissue. This was also used where an outward penetrating flame is undesirable. In this version ( Japanese Fuse ) it was installed as a retarder in almost every ball or cylinder bomb. With an average burning time of 1 cm / s, you can ideally determine the ignition point after leaving the mortar .
If the fuse is still covered with a plastic cover, it is called a safety lighter cord . With a choked detonator , it offers the possibility of detonating explosives non-electrically. The jacket makes it 100% waterproof and burns quite constantly at 0.8 cm / s without spraying sparks and flames outside. The main use is, besides military use, in avalanche blasting from helicopters, where it is usually ignited with a detonator .
A special form of fuse is an ignition method used for historical muzzle-loading weapons in the form of a slowly smoldering fuse cord for black powder cannons . It was first mentioned in 1378 and also served as a time fuse for powder cans (" hell machine "). It consisted of hemp cords from which the lignin was washed out with potash to prevent the formation of ash, which was soaked in an aqueous solution of poisonous lead sugar and then dried. So could z. B. Burning speeds of 20 cm per hour can be achieved. Wind couldn't blow out the fuses.
For ignition, the smoldering end was pushed into the gun's ignition hole, which was filled with black powder . The fuse was attached to a matchstick to ensure safe handling . It was not uncommon for both ends of the fuse to glow as a reserve in case the fuse went out. This technique was also used for early handguns such as arquebuses . Here, the shooter pressed the embers with the trigger mechanism into the powder-filled pan and thus released the shot.
The phrase smelling a fuse comes from the characteristic smell of these same constantly glowing fuse , which made the enemy recognize an ambush .
In Luntenfeuerzeug a similar type of fuse is still used today.
Visco
The Visco is the fuse most often used for category F2 fireworks (small or New Year's Eve fireworks). It consists of black powder or a mixture similar to black powder that has been applied to a thin thread. Fine thread is twisted around this thread to protect it from damage. In order to make it water-repellent, the visco is coated with a lacquer, mostly based on nitrocellulose. It is particularly well suited for firecrackers and rockets because it is cheap, water-repellent and has a very constant burn time. This is between 1 cm / s and 1.5 cm / s. Furthermore, it achieves extremely good ignition performance and fewer duds thanks to the open, spark-spraying combustion. There are numerous trade names and countries of manufacture that differ minimally in the burning time, but very different in thickness and color:
- Chinese Green Visco - Most used, thickness between 1.5mm and 3mm
- American Red Visco - Rather unknown, also available in green or red / white / blue, mostly in the trade size 3/32 "(2.381 mm)
Stoppine
In the case of stoppins , one must first differentiate between covered (also quickmatch ) and uncovered stoppine (also blackmatch ).
Uncovered stoppins consist of a thread or narrow strips of fabric on which black powder has been applied. In contrast to Visco, Blackmatch burns much more violently and uncontrollably. In addition, Blackmatch is extremely sensitive to sparks, which makes it unsuitable as an igniter. However, with large fireworks it is often used in a previously cut slot in the retarder to ensure reliable ignition.
However, if you give it an extremely loose paper jacket, you get the covered stoppine . Within the casing, the resulting sparks are propelled by the combustion gases at up to 10 m / s. Because of this enormous speed, the covered stoppine is the first choice for fireworks when it comes to establishing a connection between the propellant charge of a spherical or cylinder bomb and the muzzle. If the stoppine has a plastic coating, it becomes very water and spark resistant.
Chinese fuse
In Chinese Fuse is in very fine silk paper turned-down black powder. It is probably the oldest, cheapest, but also the most unreliable kindling of the ones listed here. Due to the large differences in density and consistency, the burning time fluctuates considerably, so that safe use is almost impossible. An enormous spark sensitivity also contributes to this. However, due to its low price, the Chinese fuse is well suited for use in banger chains.
Ignition wire
The ignition wire is probably the most important aid a fireworker uses . It consists of a black powder core with inlaid copper wire wrapped in thin plastic. The copper wire allows the pyrotechnician to twist ignition strands with one another and thus ensure safe flame transmission. It is not waterproof. There are two types of lighter wire, which differ in color and burning time:
- red: burning speed up to
- yellow: burning speed up to approx.
Legal situation
Germany
By BAM approved ignition such as electrical igniters and fuses may no evidence of the beginning of 2004 explosive law be given to persons over 18 years of permission. Any form of covered stoppine and all ignition devices without BAM approval are excluded from this regulation.
Due to the still unclear situation (the enticing or bundling of fireworks items was still only permitted to license or certificate holders according to the Explosives Act), however, the BAM Berlin published a statement on February 1, 2006, which entice class I and Class II fireworks with approved electrical and pyrotechnic ignition devices are expressly permitted to persons aged 18 and over without a permit. The connection of fireworks to a new object (bundling) and manipulation of the existing ignition points of the fireworks are still prohibited.
Explosive charges may only be released for ice and snow field explosions using a fuse; use for other purposes (e.g. demolition) is not permitted.
Austria
Category P1 ignition equipment such as B. the ignition wire or the visco may be handed over to persons over 18 years of age without proof of special knowledge.
In contrast to this, the covered stoppine is assigned to category P2 due to its higher level of danger (burning speed) and may therefore only be owned and used by people who have reached the age of 18 and who have proof of their specialist knowledge (pyrotechnics certificate).
See also
- Pyrotechnic kit - overview of general pyrotechnic items
literature
- Fuse. In: Johann Heinrich Zedler : Large complete universal lexicon of all sciences and arts . Volume 18, Leipzig 1738, column 1196 f.
Individual evidence
- ↑ Dealing with fireworks and ignition materials Federal Institute for Materials Research and Testing
- ↑ Technical rule 310 "Blasting work" (SprengTR310). Federal Ministry of Labor and Social Affairs, accessed on May 1, 2017 .
- ↑ Pyrotechnics Act 2010 (PyroTG 2010). Federal legal information system, accessed on April 19, 2019 .
Web links
- Pyrotechnics (accessed April 9, 2020)
- Protocol to the experimental lecture pyrotechnics (accessed April 9, 2020)
- Textbook 2 Large Fireworks PYAZ - Pyrotechnician Training Center (accessed April 9, 2020)
- WANO Black Powder (accessed April 9, 2020)