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== Experiences == | == Experiences == | ||
[http://www.chaski.org/homemachinist/viewtopic.php?f=8&t=89675&p=208774&hilit=removable+arch#p208813 Doug Edwards posted on <i>Chaski.org</i] | [http://www.chaski.org/homemachinist/viewtopic.php?f=8&t=89675&p=208774&hilit=removable+arch#p208813 Doug Edwards posted on <i>Chaski.org</i>] | ||
: I used to run a [[Littel Engines|LE 4-4-0]] with an oil atomizer burner without an arch. We went to a pot burner, and ended up adding an arch that went about 3/4 of the way back to the back of the firebox. The arch, by lengthening the gas path, helped to insure the fuel finished burning before entering the flues. The flues would soot up much quicker without it. | : I used to run a [[Littel Engines|LE 4-4-0]] with an oil atomizer burner without an arch. We went to a pot burner, and ended up adding an arch that went about 3/4 of the way back to the back of the firebox. The arch, by lengthening the gas path, helped to insure the fuel finished burning before entering the flues. The flues would soot up much quicker without it. | ||
: The arch was 1/4" mild steel, and lasted a number of years, even though rather warped. We had the arch initially too close to the back of the firebox, and the water glass would bubble like one of those old fashioned Christmas tree lights. | : The arch was 1/4" mild steel, and lasted a number of years, even though rather warped. We had the arch initially too close to the back of the firebox, and the water glass would bubble like one of those old fashioned Christmas tree lights. | ||
Revision as of 15:42, 11 March 2015
An arch is placed in the front third to half of the firebox. Prototype locomotives typically use brick for the arch, but live steam models most often use stainless steel.
The arch directs heat, flames, and smoke back over the fire towards the rear of the firebox. Visible smoke contains unburned combustible carbon particles and combustible gasses. The purpose of this redirection is to cause more complete combustion of these particles and gasses which make the locomotive more efficient and causes less visible smoke to be emitted from the stack. Without the arch, flames and visible smoke would be sucked straight into the firetubes without having been fully burned, causing visible smoke to be emitted at the stack, and also more soot to accumulate in the firetubes. The arch and its supports require periodic replacement due to the extreme heat they endure.
Experiences
Doug Edwards posted on Chaski.org
- I used to run a LE 4-4-0 with an oil atomizer burner without an arch. We went to a pot burner, and ended up adding an arch that went about 3/4 of the way back to the back of the firebox. The arch, by lengthening the gas path, helped to insure the fuel finished burning before entering the flues. The flues would soot up much quicker without it.
- The arch was 1/4" mild steel, and lasted a number of years, even though rather warped. We had the arch initially too close to the back of the firebox, and the water glass would bubble like one of those old fashioned Christmas tree lights.