Smoke evacuator
A smoke evacuator is a part of modern artillery , which prevents significant parts of the combustion gases produced during the shot from leaving the gun barrel through the breech that can be opened after the shot . Smoke evacuators are usually only used in guns whose breeches are located in a closed combat area in order to protect the crew from excessive influx of combustion gases after the breech block has been opened. Otherwise, these gases can affect the crew (toxic effects such as irritation and breathing difficulties) and under certain circumstances (incomplete combustion) form explosive mixtures with air.
history
The first tanks equipped with smoke evacuators were the M26A1 , which were retrofitted with the 90 mm M3A1 combat vehicle cannon after the Second World War (1948) . The first American tank equipped with a smoke evacuator in series was the M41 Walker Bulldog , which was mass-produced from 1951 , followed by the M47 Patton . The first Soviet tank with a smoke evacuator was the T-54 A, which went into series production in 1955. In these first applications of the smoke evacuator in battle tanks, they were placed near the muzzle. From the next generation (T-62, tanks with Royal Ordnance L7 ) the smoke extractors moved to the center of the pipe. In newer western tanks the smoke evacuator is attached eccentrically above the pipe axis, in Soviet / Russian models it is concentric in the pipe axis.
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Mode of action
As a technical device, the smoke evacuator consists of a hollow body made of steel in the form of a sleeve about 50 to 70 cm long, which is pushed over the gun barrel and fixed there in a gastight manner. Within the area of this case there are (as a rule four) bores in the wall of the gun barrel , which are obliquely directed from the outside to the inside . The burn-off of the propellant charge creates an overpressure between the projectile and the breech block , which - after the projectile has passed the holes - also builds up in the cavity of the smoke evacuator. After the projectile has left the pipe, the pressure drops faster there than in the smoke evacuator, the overpressure created there for a short time allows the smoke gases remaining in the smoke extractor to flow back through the bores into the pipe towards the muzzle. Since the closure is open during this flow process, the combustion gases remaining in the pipe are sucked in towards the mouth and transported out of the pipe. The effect is based on how the jet pump works .
Web links
- Engineering Design Handbook; Guns Series, Muzzle Devices , AD838748, US Army
- CR Woodley: Modeling of Fume Extractors . In: 19th International Symposium of Ballistics . Interlaken May 2001, p. 273–280 (English, ciar.org [PDF; accessed on May 17, 2016]).
- Qing-Xiang Pei, Richard Foo: Modeling and Simulation of the Gas Charging and Discharging Processes on Gun Bore Evacuator . In: 19th International Symposium of Ballistics . Interlaken May 2001, p. 281–288 (English, ciar.org [PDF; accessed May 17, 2016]).
Individual evidence
- ↑ Steven J. Zaloga: T-34-85 vs M26 Pershing: Korea 1950. Retrieved June 29, 2016 .
- ^ David Doyle: Standard Catalog of US Military Vehicles . Krause, 2003, ISBN 0-87349-508-X , p. 432 (English, limited preview in Google Book search).
- ^ Robert Icks: The Patton Tank M47. In: pattonhq.com. Retrieved June 29, 2016 .
- ↑ Stefan Kotsch: From T-54 to T-90 - History of Soviet tank construction. In: Main battle tanks in detail. kotsch88.de, accessed on May 17, 2016 .
- ↑ John Batchelor, Ian Hogg : Artillery . The history of the artillery. Heyne, Munich 1977, ISBN 3-453-52068-8 , pp. 28 (American English: Artillery . Translated by Egbert von Kleist).