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Why are steam car boiler round

Posted by ARNOLD WALKER 
ARNOLD WALKER
Why are steam car boiler round
February 11, 2003 10:00AM
I was noticing that most of the boilers were round.But in a "square" hole.
Is there any reason why a square boiler in a square hole would not work better and have more area as well? And be easier to fabricate.
Terry Williams
Re: Why are steam car boiler round
February 11, 2003 11:16AM
Round boilers are round because that is a better way to contain pressure. Boilers such as a Derr or Winslow are rectangular.
Benson in Maine
Re: flat plate boiler
February 11, 2003 11:33AM
A flat surface will flex EVERY time there a pressure change,,,,,This will cause work-hardning of the plates,,,,,early fatigue,,,,,NOT good design,,,,,for this reason if a round boiler becomes out of round in servace it should also be condemed ,,,,,For this reason flat plates are always stayed w/rods and bolts,,,,the bolts have a hole through to firebox so if there is a broken bolt it will leak hi pressure steam ,,, loco practice ,,,,Cheers Ben
Jim Crank
Re: flat plate boiler
February 11, 2003 11:44AM
Terry,
Fire tube boilers are round to withstand the pressure. A sphere would be ideal.
Water tube boilers are often square or rectangular because the case doesn't see any pressure, until the burner backfires.
The pressure is contained totally in the tubes.
JC
ARNOLD WALKER
Re: Why are steam car boiler round
February 11, 2003 11:57AM
Somewhat confused......
So,if I did a firetube the workhardening would occur mentioned early.
But not on square doble or lamonte because the pressure is in the tubes.
Right...
Terry Williams
Re: Why are steam car boiler round
February 11, 2003 01:24PM
Right.
Benson in Maine
Re: Why are steam car boiler round
February 11, 2003 04:05PM
Yes,,,the tubes are round,,,no flat surface,,Ben
Peter Brow
Re: Why are steam car boiler round
February 11, 2003 11:26PM
Another problem reported with rectangular boilers in steam cars is that their flat fronts and squarey edges impede airflow from a front-mounted condenser. Condenser could go elsewhere, but that too usually gives poor airflow. Putting boiler elsewhere, with front condenser, gives other problems.

Peter
ARNOLD WALKER
Re: Why are steam car boiler round
February 12, 2003 03:04AM
So,we are talking an electric radiator fan ,from the auto parts store ,on front
mounted boiler.With a hand built fan shroud for the condenser.
David K. Nergaard
Re: Why are steam car boiler round
February 12, 2003 04:08AM
I have tried electric fans. The normal IC fans have no where near enough air flow to help a steam condensor! The fans have been removed from my car, they made no measurable difference to my mileage on a tank of water.
Peter Brow
Re: Why are steam car boiler round
February 12, 2003 11:44PM
Arnold: Even with a fan, it's still good design to avoid blowing air straight into a flat wall. Of course, you could just add a curved or V-shaped air deflector to the front of a square boiler. Attention should also be given to cooling air exit route around any boiler in a front-boiler, front-condenser layout.

David: That's an eye-opener! Thanks for the report. Perhaps confirming this, Peter Barrett at one time had (has?) 4 very large IC(?) electric fans on his very large rear-mounted condenser. Oddly, these pull hot air from rear engine/boiler compartment thru the condenser, _and_ reportedly give very good exhaust condensing, so go figure.

Personally, I am looking at maximizing internal steamed surface area of a front-mounted condenser, without a fan. Plus a couple other tricks.

Peter
Andy Patterson
Re: Why are steam car boiler round
March 06, 2003 09:46AM
Some water tube boilers like the White or Doble could be round to simplify the gas flow through them or make it easier to form the coils.

There were box shaped boilers in some old setamers. The Doble Detroit and the Bryan are two examples.

[www.greenhills.net]

The Bryan Steamer there, owned by Al Reynolds, has a box shaped boiler simular to that of the one shown below used in their tractor.
David K. Nergaard
Re: Why are steam car boiler round
March 07, 2003 03:29AM
Peter, the problem is not steam surface area, it is AIR surface area. Getting heat into or out of air is the major problem in both boilers and condensors.
ARNOLD WALKER
Re: Why are steam car boiler round
March 07, 2003 04:07AM
The bryan steamer is what had me looking at square boilers.
Though,I figure it would be a lamonte version of that.
Dick Vennerbeck
Re: Why are steam car boiler round
March 10, 2003 05:51AM
Here's trick that might help condenser cars. The guys that race the P51 Mustangs bleed a tiny amount of the coolant off and introduce it as a very fine mist from a spray-bar mounted just ahead of the radiator on each side of the plane. The increased cooling from evaporation on the radiator surfaces allows them to close down the cowl flaps a little more, this reduces drag and increases speed. I'm not sure if the total water loss in a Stanley would be offset by the gained mileage of the water used for evaporative cooling. I could never calculate this myself and I sure as heck don't know where the flaps are on a condensor Stanley!

Arnold,
The Bryan steam boilers are a water tube type in a square casing and can still be purchased from the manufacturer.
David K. Nergaard
Re: Why are steam car boiler round
March 10, 2003 02:06PM
Dick, to condense a pound of water you would have to evaporate a pound of water. Much simpler to just blow it off!
The trick works for the IC radiator as they only need to coil liquid water by 50 degrees or so. On that basis, evaporating one pound will cool nearly 50 pounds.
David K. Nergaard
Re: Why are steam car boiler round
March 10, 2003 02:08PM
OOPS! Arithmetic error. I should have said 20 pounds.
Mark Stacey
Re: Why are steam car boiler round
March 10, 2003 03:04PM
The spray bars on unlimited race planes use water from tanks not the coolent that circulated through the engine. When I was at Reno in 1999 there was one truck supplying the planes with two types of fluid, one one a water methanol mix for injection into the supercharger to supress detonation and the other which I recall as distilled water for the radiator spray bars.

Thought I better check. Here is a full description see pg24
[www.outerbound.com]

So for a condensing steam car if you take water from the storage tank and use it to spray cool the radiator you could possibly improve the vaccuum and thus power but at the expense of water mileage?

Cheers
Mark Stacey
David K. Nergaard
Re: Why are steam car boiler round
March 11, 2003 01:10PM
I suspect you might do better just taking off the exhaust pipe at the engine. I doubt you could get significant vacuum without using a lot of water.
Andy Patterson
Re: Why are steam car boiler round
March 12, 2003 12:14PM
I would not dismiss the idea of using a water spray to quick. As David said it could take as much or more water spray by weight to condense steam as that your are condensing. But that is only using the water as the condensing agent.

I thinks the spray condensing idea is a bit more complicated. You are not just using the spray as the heat absorbing agent. The air flow is also involved. The steam is at a higher temperature usually at 250 or more degreed F. The water spray is at some lower temperature. You are not neccessarly heating the water to the boiling point. Water does not have to be at the saturation temperature to evaporate. Wet your hand and blow across it. The water does not heat to 212 degrees and the then avaporate off your hand. I could go on about humidity and equlibriam etc.. but you get the idea. Right. At any rate you have a very high water vapor content air mixture passing on through the condenser. That high humidity air can still absorb a lot more heat. Basicly the spray would pull heat from the front surface area of the condensor and lowing it's temperature. That would inturn lower the temperature of the air(relative to not using spray) and increase the air's water content. So now we lower temperature air with higher water content passing on through the condensor. Overall we have increased the average temperature differance bettering the heat transfer of our condensor. Anyway I think you would get more from the water spray than just the heat of vaporization. Just how much more would be hard to say.

At any rate I would not use such a system except maybe to reduce pressure in the condensor at high condensor loads. That is where it might show the most benifit.

Though, I think this working is margional, it is something that should be tried. It is easy enough to give a try. A small electric camper water pump should work. They automaticly maintain 15 or so PSI water pressure. A pressure activated valve that lets water to the spray nozels when the condensor pressure exceeds some point. The spray rate should never be excessive and waste water. This could be tried on most any steamer. I think it would work best on a cross counter flow design. The condenser would have two or more layers. Exhaust steam would proceed through the condensor from the back layer to the front. Air from front to back.

It would still have to gain quite a bit to make up for the extra complication and weight it would add to the system.

We are way off subject here.
Caleb Ramsby
Re: Why are steam car boiler round
March 12, 2003 02:01PM
In regards to the water spray system I think that for test purposes that a manualy actuated system would work the best. In this way one would have simplicity of design, instalation and have a positive control of it's use. Just go to the junk yard and un-install a windshield wiper water spray system from a car. There is already a pump, tubing, spray nozel(s)(some have more than one), water tank and a switch. In my opinion this would be the easiest and cheepest way of testing how well this would work.

Coincidently the day that this subject was brought up was the very same day that I came across an article in an early 1950's Popular Mechanics magazine that described a farmers system of cooling a radaitor in a tractor. Just spraying water over the radaitor.

My main concern in using this system would be the contamination of various components that would be saturated. However I don't think that it would any more extreme than a good rain.

Conversly I believe that one of the easiest ways of increasing the ability of a condensor or heat extractor to function, is to increase the volume of fluid by which the heat is drawn away. In a steam cars system this would be the air which pases over the condensor or other heat extractor device. To quote a gratuitously used phrase, just "Pump up the volume".

Caleb Ramsby
Andy Patterson
Re: Why are steam car boiler round
March 13, 2003 06:34AM
Hi Caleb

Your last paragraph is about right. But I would say it is the mass flow you wont to increase. That is what I was trying to point out in my origional post. Increassing the mass flow can be done two ways. One as you stated: Increase the volume flow. Two: increase the density of fluid by which the heat is drawn away. Or use both. The spray idea increasses the density and volume to some extent.

Thoes windshield fluid pumps more squrt fluid on the window then spray. I think it could be adopted though. You might need to modify it to break up the water stream. An agro supply store will have sprayer jets that could be used.
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