Talk:Bore evacuator

I can't understand this
"The evacuator is a reservoir that holds the super-heated, high-pressure propellant gases produced by the firing of a shell, then releases them as the shell exits the barrel. When not in use, the atmosphere inside the barrel remains the same as the surrounding environment; thus it is the same, or nearly so, inside the evacuator." Sorry, but I don't get anything from this. First, what is the mechanism by which the gases get stored in the reservoir ?... thus it is the same... ?? Without some explanation of the contruction and components of the evacuator, and the basic mechanics involved, this doesn't make sense. E.g. an explanation of what happens progressively from firing to shell leaving barrel to breech opening, and where the gas is at each point, would help. Rcbutcher (talk) 16:16, 13 June 2008 (UTC)

Note: The bore evacuator itself is nothing but a steel empty (hollow) tube constructed of thick sheet metal; it twists on and off (screws on and off; it is threaded) the gun tube for maintenance (cleaning the gun tube/cannon barrel). When the evacuator is removed, you can see holes bored into the gun tube all around the barrel, usually one ring of holes, each hole possibly an 1/8" in diameter, with an indented edge facing the muzzle end, shaped somewhat like a shovel; these holes are the entry/exit areas for the gas as the projectile moves down the bore of the gun. The author of the article stating, "...atomosphere inside the barrel..." might be trying to tell the reader that the bore evacuator contains no computerized equipment, chemicals, mechanisms, or anything else...as gun tubes today often have "thermal sleeves" wrapped around their barrels to maintain a steady temperature while firing. Possibly the author did not want the reader to get the idea that the evacuator was related to the thermal sleeve and gun tube temperature.  The term "reservoir" may have thrown some readers also, the evacuator is a reservoir ONLY when the spent fumes (gases) enter the evacuator when firing. When the shell (warhead) is on it's way, the bore evacuator is usually empty too. It takes only a millisecond for all of this to happen. As fast as firing any gun. As for keeping gases out of the turret; in Vietnam, M48 Patton tanks firing their 90mm main guns had plenty of gases inside their turrets; possibly the evacuators needed cleaning; possibly they were worn out; or more than likely they couldn't handle the rapid firing of the main guns, and the smoke over-loaded the bore evacuator system. It could get so smokey inside those Patton tank turrets, that crewmen could not see, and had to hold their faces upwards to the loader's hatch to get breathing air. —Preceding unsigned comment added by 76.114.15.192 (talk) 23:38, 21 December 2008 (UTC)
 * Thank you, that actually makes things much clearer than the article itself. Muad (talk) 00:21, 6 April 2012 (UTC)

This article would really benefit from a diagram. I think I understand how it works and would be willing to whip something up in autoCAD but I have no idea how to upload it. — Preceding unsigned comment added by 66.38.56.124 (talk) 14:51, 17 February 2014 (UTC)

Video Graphic
I would like to point out that there are only one series of holes at the turret end of the fume extractor not a set at both ends. The fume extractor is pressurized when the round travels past the openings in the barrel inside the fume extractor and when the pressure drops tin the barrel after the round has left the barrel allows the high pressure gas in the fume extractor to re-enter the barrel and blows the remaining fumes in the barrel out the muzzle. This all occurs before the breach is opened at the end of the firing cycle. I'm a retired Armoured Crewman and I've been stuck with cleaning the fume extractor more times than I wish to remember. 142.52.203.4 (talk) 18:27, 8 March 2018 (UTC)