How did the engineer regulate the amount of smoke coming out of the stack?
Nick
To keep it simple, the fuel to air ratio is what determines the preponderance of clean burning or smoke. It involves more than that...impurities in the fuel, for example. But for the sake of simplicity, the fireman regulates the fuel, and he also regulates the blower which draws air through the firebox with a jet of steam rising up out of the smokebox. Again, not so simple. The other guy, the fellow running the engine down the tracks, is playing with the throttle as he attempts to maintain speed and control of the engine's movements. Opening and shutting the throttle imparts more steam or less into the volume coming out of the stack since the cylinders evacuate via the stack. Therefore, the team work in concert, each responding to the efforts of the other, to get the engine to perform both efficiently and effectively...two words that don't mean the same thing.
The engineer is responsible for the engine and all other crew. He watches the stack and the gauges, plus calls signals and such when the train encounters them on its journey. He gives feedback to the fireman, who is also watching his gauges and the stack to judge the performances of the engine and his own efforts to regulate the use of fuel. If the engineer sees that pressure is falling, and that the stack is apparently clear and the engine firing well, perhaps he is using steam faster than the engine can supply it. Adding more fuel may or may not derive the result of more steam.
If anyone wants to get into the details more than this, including the orignator, be my guest.
I am familiar with oil burners which have no cinders. Interestingly, in 1917 the City of Chicago measured the amount of cinders produced by coal burning steam locomotives and it amounted to 450 tons! As Selector mentioned,.in real operating conditions it was the result of poor firing.
In both cases, the fireman is responsible for a "clean stack." Many a fireman was written up for black smoke. In the case of an oil burner, the fireman has two valves at his disposal. The fuel valve that controls the flow of oil into the atomizer, and the atomizer valve itself, which controls the pressure of the steam that is used to force and disperse the oil through the atomizer into small droplets for burning.
Black smoke is caused by a fire is not burning correctly due to too much fuel oil. The fireman then increase the draft of air using dampers and the blower or reduce the amount of oil to the burner. Blue smoke indicates too much steam pressure is being applied to the atomizer, and so the fireman must reduce the steam pressure. A light grey smoke is seen when the fire is properly adjusted, while no smoke, not surprisingly, means the fire is too light and should be increased.
Bunker C oil was tough to utilize in cold weather, it tended to thicken...a real challenge for firemen.
Nothing is more fairly distributed than common sense: no one thinks he needs more of it than he already has.
Selector, isn't the blower primarily used to maintain the draft when the engine is standing still? I have always understood that, when running, the exhaust from the cylinders usually provides sufficient force to mantain the draft through the flues.
Wally, there are times when the fireman has to make black smoke on an oil burner. If he did not, the flues would fill up with soot. From time to time, the fireman introduces sand into the firebox, and it is immediately drawn through the flues and it scours the soot out.
Anyway, whatever the actual source, black smoke comes when unburnt fuel (cinders, soot, or whatever else) goes through the smokestack.
Johnny
Johnny, I believe you are largely correct, although my understanding, based on a British simulator and from some reading, is that a blower is still useful up to a certain speed. I don't know what that is, but it seemed that the instructions for the simulator, which was mostly input variables and precious little graphics, required at least 10% blower all the time. I honestly don't believe that a blower is of any use above 15 mph or so, and maybe even as low as 10 mph.
The black smoke, we agree, is a sign of either inadvertent or intentional misfiring. Inattention would get perhaps both crew members written up if it was persistent and observed by a foreman. But it was sometimes intentional for visual effect when the press or rail fans were expecting to see it, and by prior arrangement/agreement on roll-pasts.
There is a rather good video on youtube of the Union Pacific FEF 844 leaving Greeley.
http://ca.youtube.com/watch?v=O8BXipiLfwA&feature=PlayList&p=DFD9A233E1231B07&playnext=1&index=20
You can see the smoke going clear, then black, then clear, then black, as the fireman, apparently attentiive, struggles to find the right mix as the engineer continues to demand more steam and force more of it out of the stack with each exposure of the exhaust ports by the valves. Eventually, as it nears about 40 mph, and on up the firemen finds the right settings for the throttle demands and the stack goes quite clear...which I would think is optimal...not positive.
-Crandell
On a hand fired coal burnere, adding fresh coal when lightly loaded will almost always produce black smoke as the dust and dirt burn off. Then when the surface of the new coal reaches the same burning temperature as the rest of the fire the stack will clear again.
dd
Thank you to; Selector, Wallyworld, Deggesty and Didance. I appreciate your responses.
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