S. ConnorAn air pump would not work well as a form of draft stimulant, mostly because it does not exhaust a great enough volume of steam. You wouldn't want pulses for a draft anyways; steady and even is what you want, and the blower does just that. The blower is much easier to maintain anyways. The air-pump exhausting through the smokebox is just a point of convenience.
A Westinghouse cross-compound air compressor (which is what I presume is being meant by 'air pump' here) is intentionally designed to use the bare minimum of steam, exhausted to the lowest pressure (and hence lowest remaining heat content) to achieve the desired reservoir pressure. It does this more efficiently than most rotating pumps can. But, as noted, not only is the mass flow greatly limited even for 'banked' firing, the actual exhaust pulses are too separate and weak to provide much, if any, actual draft energy.
Note that many roads used separate external booster exhaust tracts rather than 'siamese' them into the stack for added draft, and at least some roads that started with them 'combined' subsequently separated them -- probably because the draft increased too violently with speed and started causing the usual sorts of problems with staybolts and such. There is FAR more reason to try using booster exhaust for draft than air-compressor exhaust...
The 'ideal' thing to do with compressor exhaust would probably be to condense it into feedwater, either in the tender tank or the cold-water side of a feedwater heater. That would recover the enthalpy in the exhaust steam as well as the water mass, and have the effect of reducing the effective back pressure on the LP side to marine levels. But be sure to read the various Angus Sinclair comments about 'patent' thermodynamic improvements from these types of auxiliaries...
BoydLet's say if a person theoretically emptied a 50 pound bag of popcorn into the firebox of a steamed up locomotive. I'm sure it would be a mess but would popcorn come out of the smokestack?
Boyd, you can answer this yourself. What is the temperature in a working firebox, and what is the time-of-flight of a particle (dumped in at the firedoor, in this example) through it? And thence through the flue or tube, in relatively highly turbulent flow, then a reversal through the Master Mechanic front end and contact with the 'self-cleaning' screens -- remembering what it is they do.
Now look at a piece of popped popcorn, and consider what it consists of -- its composition and its mass-to-surface-area. If you like, test a piece with a propane torch to see how long it takes to be something other than the kind of popcorn you expect to see come out of the stack. Or whether or not when it 'melts back' under the sustained heat (in the reducing conditions prevailing) it will be glowing nicely when it emerges...
That Viscose popper ... now, that's interesting. My guess is that it's acting like a giant version of a hot-air popper, with the seeds circulating in the blower draft and the popped kernels with their larger surface area being selectively ejected.
STEAM ENGINE ANATOMY 101 -
There is no "mechanical blower", with a "blower fan" and "blower motor" on a railroad steam locomotive in the traditional sense!
Its just a valve and nozzle that blows some steam up the smokestack to create a draft! - called a blower because it blows air.
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The purpose of an "brake system air compressor" or better a "cross compound air compressor" is to fill the large steel air tanks with compressed air for releasing the train brakes. The compressor only runs when it is needed. Any engine designer would use as little of this steam as possible to pump air because it is a parasitic appliance and wastes steam created and used to drive the locomotive. Consequently the exhaust steam pulses out in the well known cross compound air compressor - "ka-thunk.... ka- thunk" of steam - well likely it wouldn't do more than blow the hat off your head.
Really big steam locomotives like UP 4014 and UP 844 and N&W 611 etc. had two - "cross compound air compressors" - one on each side of the locomotive - this allowed them to pump up air pressure quickly to release the train brakes. Consider on a large 100 car train doing this quickly - releasing the brakes to move the train - was important to maintain schedule.
To pump up pressure on 100 train cars in order to move or to release the same air pressure - well the air would move through the long train slowly because air takes time.
Two "cross compound" locomotive air compressors became fairly standard equipment. You can identify them because of their shape. Two pistons and cylinders pumping up and down into two parallel air cylinders - giving in effect a machine of four round chambers mounted vertically about 3 feet tall with a tiny steam engine in the middle. Check any steam locomotive photograph and look for the compressors often found under the engine forward running board ladders.
Air compressors were occasionally mounted on the side of the locomotive and early 1910 era the "single stage air compressors" were small with only one piston and cylinder. These were usually mounted on the side of the boiler above the running board. As the designs became better they eventually found their way to the front of the locomotive - usually one on each side where the "cross compound compressors" were covered with sheet metal guards to protect them from damage in the event of a collision.
Some railroads like C&O and Great Northern prefered to mount these two "cross compound air compressors" - in the "flying" position! Thats right - "flying cross compound air compressors" - even sounds racy - mounted on the front of the smokebox right ahead of the smokestack - It gave the steam locomotive a rather sporting look!
I don't think "cross compound air compressor" exhaust was ever of volume sufficient enough to bother venting up the engine stack. It was. however, one of the signiture SOUNDS or NOISES that the living and breathing operating steam locomotive made. A constant sound of "ka-thunk ka-thunk ka-thunk........ka thunk" that let you know the train brake system was being kept up to pressure to run. "ka thunk....ka thunk...ka thunk!"
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It might also be worth noting that the railroad steam locomotive was not a kitchen appliance. Considering the ban on tobacco smoking in America the breathing of coal smoke and or oil fired locomotive exhaust by the steam locomotive crew was and is a health concern. Likewise food prepared in the presence of the burning of heavy metal laden fuels was also not particularly condusive to the palate or health either.
Poison laden creasote or copper napthate preserved railroad "cross tie" campfires are also a no-no for eating and breathing.
Doc
Dr DTo pump up pressure on 100 train cars in order to move or to release the same air pressure - well the air would move through the long train slowly because air takes time.
This is an old wives' tale that keeps cropping up. The two compressors are to handle the larger mass of air intake that is needed to fill all the trainlines and car reservoirs; the actual difference in charge pressure from end to end is not that much of an issue when pumping up a long cut of cars. A far more important source of slow charging comes when it's cold outside and all the little seals at the gladhands, etc. are blowing by. (I remember an article in Trains, many years ago, about a dead trainload of beets...)
The added economy of cross-compound compression deserves a full discussion: how the transfer of pressure from the steam to the air is done so effectively.
"There is no "mechanical blower", with a "blower fan" and "blower motor" on a railroad steam locomotive in the traditional sense!
Its just a valve and nozzle that blows some steam up the smokestack to create a draft! - called a blower because it blows air."
Actually, many steam locos in the Soviet era (Uncle Joe's era, to be more precise) did use blower motors and fans, because that's the way Stalin liked it.
And no one bothered to tell Joe that there was a better way, for reasons that should be obvious.
And there were steam locomotives in South Africa that used fans for draft. These were the locomotives with the steam condensing tenders that were used in very arid areas of the country.
NDG
Thanks for the great picture of a "Westinghouse Cross Compound Compressor" I am guessing that is you standing in the picture. Your comments make me wonder if they still supply repair parts for these units?
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Well I guess its time to introduce the subject as "pneumatics" which is the operation of machinery by air pressure. Railroad train brakes were one of the first successful and modern uses of high power air pressure for the everyday operation of railroad equipment. The marvel of air operated train brakes at the end of the 19th century was considered a miraculous use of modern science in that age of the Industrial Revolution.
Today I wonder if modern Americans have any appreciation for the use of safe modern pneumatic air operated appliances that are so common in our everyday life? So WHAT IS AIR PRESSURE anyway? That"s right Virginia - modern speeding trains today are still stopped by air!
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Air tools are the mechanics friend for working on the automobile - air wrenches, air chisels - air hammers. Air tools are used today to break up the concrete in city streets by use of the guy in a hard hat driving the belly bouncing "jack hammer" of modern road construction. Air is also used to lift your car in the repair shop by the automotive vehicle hoist so repairs can be done underneath it.
Air pressure is really the science of the engineering of fluid power. Which can be done in two ways by the use of "hydraulics" through the application of liquid pressure, or though the use of "pneumatics" by application of air pressure.
Of these two systems "pneumatics" the engineering of air pressure offers its advantages of simplicity - reliability - safety.
Air operated machinery is simple in design - look at a railroad freight car - every car has to work with every other car and they all have to have a simple and easily repairable and operable braking system - simplicity!
Air operated machinery is reliable - it functions well even when not everything is perfect in the way of sealing the pressure and the natural cushioning of the air prevents the systems from pounding themselves to pieces with shock. Air pressure can be stored in tanks to operate even if the machinery that powers it breaks down. Train brakes will operate even without the locomotive being operable - reliable!
Air operated machinery is safe - it has a proven track record of operating continuously across time as it was designed to operate. Train brakes that operate safely time after time, no matter how many cars are coupled together, or how worn out they are, and how old they are - and are easy to use by the crew - safety!
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Compressed air is supplied by storage of air in a tank or reservoir and also by an air compressor. The "Westinghouse Cross Compound Compressor" used on steam locomotives was remarkable. Because it was a COMPOUND compressor it was basically two single stage compressors mounted side by side feeding air and steam from one cylinder set to the other set.
This ment it was a COMPOUND OPERATION BY STEAM AT THE SAME TIME a COMPOUND SUPPLY OF AIR!
A HIGH steam pressure cylinder drove an air compressor cylinder of LOW air pressure - which steam - fed into a LOW pressure steam cylinder that at the same time upped the air pressure sent into a HIGH pressure cylinder. The steam was used up in two stages and the air pressure went up in two stages at the same time.
Also these two systems were mounted side by side making one machine and as the steam was used up twice in the two cylinders the air pressure doubled up at the same time in the two air cylinders.
Highly efficient and extremely compact was the name of the Westinghouse system! AND MORE - the first set of compressor cylinders - well they automatically controlled the second of compressor cylinders! This in effect DOUBLE STAGED the compressor!
FURTHER it was turned on by the engine crew and LEFT ON so that the compressor would pump up the train brake air pressure whenever it needed to. AND the compressors would run at FULL POWER and then suddenly turn themselves OFF when the pressure got up to max. SIMPLE RELIABLE SAFE! Automation in 1910! UNbelievable UNthinkable!
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Generally every steam locomotive of every railroad had two of the "Westinghouse Cross Compound Compressors" giving tremendous, reliable train braking and safety on the railroads of America.
Westinghouse train brakes were a vast improvement over the manual brakes of the post American Civil War generation.
Before air brakes were invented every caboose on every train had a crew of "brakemen" whose job it was to run across the top of every car on the train and set the brake wheels of each car one by one - by hand. In rain, snow and sunshine the "brake crew" would go to work scurrying across the tops of the car to slow down the train when the engineer signaled EMERGENCY on the whistle.
Pneumatic operated train brakes are the first modern appliances invented for the American Railroads and they are still here with us today. Simple Safe and Reliable.
[quote user="RME"] working temperature in a coal or oil fired steam locomotive firebox averages 2500 degrees F any popcorn would not pop but be totally consumed in a few secounds. back in the 70's I was working as a hostler at Orbisonia, Pa East Broad top RR found an old piece of steel boilerplate in the shop with a hole in one end and an old timer who used to work at the shop told me what it was for. He showed up about midnight the following night at my invitation and brought more grocieries thean I had brought I had the plate inside the firebox for about two hours at that point used the hook and hole to retrieve it set it on the deck and he said I got this big blob of butter onions carrots celery steak I provided about 5 pounds ( I was young then) I then became aware of other men outside the cab and after talking with them sat down to the best meal I'd had in months with four former EBT employes on a beautiful moonlit night one of the guys showed up with a picnic table in the back of his truck and sheepishly admitted my knees won't hurt if i use the table too bad. I wish I had a recorder because the stories I heard that night were to a 20 year old were like being thrown back in time. I complained about the coal we burned 95% slack ( fines aka powder ) the guys laughed at me and one said thats all we ever got for the power house or the engines. I learned then and there it was called "mine run" meaning what they couldn't sell. I then learned on the spot how to fire with slack coal and damn if it didn't make a difference and yes the coal came out of EBT owned and operated coal mines. Even in 1970!!
I appologize as I just realized I sorta drifted off topic. Starnge how the mind works when answering a simple question up pops another memmory.
Ahh the good ole days
Jim
Back in the 1950's all freight equipment used the AB brake valve which utilized a split air tank one side was for the service brake and both sides came into play when the brake was thrown into emergency to release the brake manually you pulled a rod attached to the AB valve which drained both sides completley to release the air brake so when a trian of 100 cars was made up and the feed valve on the brake stand was set to 80 pounds it would take a good 20 minutes or more to pump up the air enough to test the train brake as you had a lot of air tanks to fill and you couldn't test the air untill you had 65 pounds of air on the buggy gauge. then the engineer could make a service brake application of 15 pounds to set the brake once the carnockers (at the originating yard ) inspected every car they would give you the release signal and after verifying they released the ok on the brakes and remove the blue flag. Nowadays when you pull the rod to release the brake on aa ABD equiped freight car they have whats called a quick release a quick jerk on the rod and the brake startes to release WITHOUT draining the air tanks this means a much shorter charging time to make a brake test as not all the cars air tanks are empty.
Getting back to the OP's original question of what happens when you put popcorn into a firebox of a steam locomotive: Today, I had my coal burning 12" gauge steam locomotive fired up. I tried 3 different shovels of popcorn in it (Orville Redenbacher Original) and got the same result 3 times... not a single kernal popped. It simply went up in flames. We know that popcorn "pops" because the heat causes the moisture in the kernal to turn into steam and expand until it ruptures the outer layer. My theory is that the coal fire is so hot, it immediately burns through the outer layer before the moisture has a chance to expand into steam. No containment of steam by the outer layer, no "pop". I observed that there was moisture sizzling on the fire for a few seconds after the popcorn was dumped in, but it quickly evaporated and the rest of the kernal consumed in the fire. It's just too much heat, applied too quickly. Anyone else give this experiment a try yet?
JamesP Anyone else give this experiment a try yet?
OK, everybody out there that's running coal-fired live steam, give it a try.
JamesP, I'm just curious: how much boiler pressure do you run with?
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"A stranger's just a friend you ain't met yet." --- Dave Gardner
Pops lift at 125 psi on this engine. By the way, I guess I should mention that the locomotive was stationary during the popcorn test, with light blower - enough to keep the smoke inside the firebox, but not so much that it sucked cold air into the flues. I do have video, but it is as boring as it sounds. However, it may be part of my next Youtube video of running trains... maybe I'll get it done this weekend!
Well there you have it sports fans! Oil in a pan is still the best way to pop corn!
Trains, trains, wonderful trains. The more you get, the more you toot!
Here you go... from yesterday's experiment! A short video clip of popcorn in the firebox can be seen at 00:35:
JamesPHere you go... from yesterday's experiment! A short video clip of popcorn in the firebox can be seen at 00:35:
What if is was left on the coal scuttle rather than just dumped in the fire?
Never too old to have a happy childhood!
BaltACD What if is was left on the coal scuttle rather than just dumped in the fire?
I suspect if it was left on the scoop, it would have a better chance to pop. Especially if one was to put a pool of steam oil on the scoop first...
Penny TrainsWell there you have it sports fans! Oil in a pan is still the best way to pop corn!
Au contraire, ma soeur -- hot air is the gold standard for getting all the kernels to go without some of them misfiring, scorching, or being soggy with ... oil. That is what made the 'corn in the smokebox' approach work as well as it did, and in part why the kernels that were ejected were edible.
Popcorn on the shovel, with or without oil for heat transfer, would suffer from the same trouble you'd get with Jiffy-Pop if you removed the foil first. Kind of like a stoker with the steam jets built randomly into the coal ... if you think about it a bit, not a good idea. And most kinds of 'covering' to keep the popcorn co-located with the shovel won't allow proper popping to the state you want.
You could adapt the Jiffy-Pop cover approach to a shovel, with a little care, and it would work nicely if the attach points, the sealing, and the venting were arranged right. But you'll still have scorching on the bottom, and it will be slow compared to popping in hot air. What you need is a device that takes a tap of hot gas (or even air from a good combustion-air preheater) and arranges to levitate or agitate the kernels in the stream, the way the commercial hot-air poppers do. This might be arranged quite nicely with a small fan on one of Porta's secondary-air vents or a duct that could be inserted through a partially-ajar firedoor...
I like my corn popped the Humphrey way.
Penny Trains I like my corn popped the Humphrey way.
Hubert Humphrey was a popcorn expert? Who knew?
Firelock76Hubert Humphrey was a popcorn expert? Who knew?
See? You learn something new about presidential history every day!
D.S. Humphrey, founder of the Humphrey Popcorn Company. His popcorn method was so popular he earned enough money to buy Euclid Beach Park.
Penny TrainsI like my corn popped the Humphrey way.
To say nothing of the taffy. But the Humphrey way (and yes, it's the correct way) is with hot air...
RME Penny Trains I like my corn popped the Humphrey way. To say nothing of the taffy. But the Humphrey way (and yes, it's the correct way) is with hot air...
Johnny
You know, don't let anyone tell you Basset Hounds are stupid. We had three at one time, Bruno, Lonzo, and Darla, and whenever they saw me pull the hot air popcorn popper out of the cabinet they came rumbling into the kitchen to catch the "fliers."
They KNEW what was coming!
Our current, Ginger, hasn't seen the popper in action yet, but I'm sure she'll catch on just as quickly.
RMEBut the Humphrey way (and yes, it's the correct way) is with hot air...
From, Euclid Beach Park is closed for the season, by Amusement Park Books, Inc., Volume 1, copyright 1977, page 18: "The Humphreys had a different way of making popcorn. Dudley related that '...we used to put our corn into the hot kettle, mix the lard and salt right with it, cover the lid, and stir it up with a big spoon. That kept all the sweetness of the corn in the popped kernel and seasoned it at the same time.'"
Well, if you don't want to trust me, perhaps you would trust a couple of Humphreys.
Around 2:02-2:04.
(The lard and salt were used to flavor the popcorn kernels as they popped, as opposed to dredging the stuff on afterwards when you couldn't get a thin, even layer on there; you will notice the absence of butter in the discussion of seasoning which is a heads-up...)
RME Well, if you don't want to trust me, perhaps you would trust a couple of Humphreys. Around 2:02-2:04. (The lard and salt were used to flavor the popcorn kernels as they popped, as opposed to dredging the stuff on afterwards when you couldn't get a thin, even layer on there; you will notice the absence of butter in the discussion of seasoning which is a heads-up...)
There are corn fired boilers and furnaces for heating your house. If the corn popped, I doubt they would use corn.
Ken Vandevoort
JamesP Here you go... from yesterday's experiment! A short video clip of popcorn in the firebox can be seen at 00:35:
Oh, look! A "Footstrong" turntable!
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