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Re: Boiler Discussion Thread/Boilers only-
Posted by: George Nutz (---.worldpath.net)
Date: July 29, 2002 10:20AM

<HTML>Terry,
That would be great if you could e-mail me a photo, you probably have seen pictures of the boat Lamont in the papers section---a design to be very rugged and secondary was smallest size etc. . So the one you built was much like the one in that ill-fated car at the MIT-CalTech race, it looked very professional.
I think John Woodson would appreciate a copy but few on this phorum realize the great and tremendous difficulty he has had the last several weeks with a huge computer crash of both hardrives and he works all night for us to continue website functioning and try and get things back up to snuff, so his picture posting has been disabled for a few weeks. It would be nice eventually to have a good picture of it in that section.
Thanks, George</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: peter heid (---.netheaven.com)
Date: July 29, 2002 10:21AM

<HTML>Peter,</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: peter heid (---.netheaven.com)
Date: July 29, 2002 10:52AM

<HTML>Peter,

As I tried to say before posting a blank response:

A bonecourt design could be easily run in varying stages with the individual combustion tubes being shut down and restarted as needed. The fuel and air would need to be shut off individually but each tube when running would get the perfect air fuel ratio and burn in the appropiate sized combustion chamber. A few types of materials have been tried for the material to provide the heat for catylitic combustion but plain old iron strips seemed to work the best back then. The iron heated quickly and allowed a fast changeover to catylitic combustion and easier replacement than refractory material. The ignitor material touches the tube wall in as few places as possable to prevent the conduction of heat from it. With todays modern controls, firing each tube individually would be no problem and if one failed you would still be driving.

George,

I will try to find some references for you, I forget which books it is shown in. The size seemed quite reasonable and I will try to get more specs also.

Peter Heid</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: tom ward (---.client.attbi.com)
Date: July 29, 2002 05:35PM

<HTML>All the monotube designs I've seen so far are the water tube type. Is there any good reason a fire tube type monotube with forced draft would be a reasonable way to go?</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Peter Brow (---.public.svc.webtv.net)
Date: July 30, 2002 05:41AM

<HTML>Hi George,

Yes, long high-output monotubes have high pumping resistance. Parallel multipath once-through design is an attempt to reduce the tube length/pumping losses with smaller diameter tubing having a fraction of the tube weight per square foot of heat-transfer area. I think(?) the flow resistance in an 8-path 112 sf boiler with 1/4"OD, 3/16"ID tubing would be equivalent to an approximately 214' monotube with 0.53" ID.

I think(?) a boiler designed to Doble parameters would put a lot more water/steam through a (much longer) 1/2" tube than I am planning. Also, as I recall, Doble tube diameter increased from one section to the next.

For comparison, the Scott-Newcomb boiler produced 500 lbs/hr at about the same pressure/temperature with a 1/2" ID monotube 367 feet long. Pumping losses must not have been excessive, as they reported average-conditions fuel mileage of 12-15 mpg in a tall, airdraggy 1920 vehicle of over 5200 lbs loaded weight.

I am trying to locate your estimate of the pressure drop in my previous 143' path (3/16" ID) concept at 5x (700lbs/hr x 5 = 3500 lbs/hr; 3500/8 paths = 437.5 lbs/hr per path) circulation. As I recall, pressure drop was way too high to be practical for Lamont circulation, but acceptable for a once-through. With only 1-2x flow rate (87.5-175 lbs/hr per path, once-through), the pressure drop would be much lower.

An equivalent Lamont would have much lower pumping losses, however. Another plus for the Lamont.

I have read that Dick Smith built a successful(?) small monotube with 1/4" tubing. I seem to recall a photo of him with the small tube stack in his lap; it looked like a loose coil of large-diameter wire. Does anybody know more about this design?

As noted, once-through multipath design is an untested & purely experimental approach which I am not recommending. It is just something I am personally considering trying, to see if/how it works. I hope that relatively tame parameters will increase the chances of success.

Peter</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: George Nutz (---.worldpath.net)
Date: July 30, 2002 06:15AM

<HTML>Peter,
The boiler in William Brobecks very successful California (DOT supported) bus was a two parallel pass and believe Besler also made a few two parallel pass boilers. Big Lamonts, to cut down circulating pressure, would use many paths with flow restrictors in them to equalize each different path to have the same relative 5/1 flow ratio per pound of steam evaporated per path. A standard watertube boiler is a huge bunch of parallel paths but as each tube is relatively very short adequate circulation is available. Look at Chapter 8 in the B&W book and look at the flow equations, the need to know the absolute viscosity and changing conditions going on in the tube---this means you need to know the amount of heat transfer along the length of each tube---it can be done. Don't forget to include all the flow losses due to bends and find the longer equivalent tube length. If a multi-path "monotube looking" boiler had all identical paths with each one receiving the same heat input then the problem of a section not getting water would be minimized(but not totally eliminated). A multiple piston feedwater pump could have a piston feeding each parallel circuit and as long as the pump behaved properly each coil would have equal water, or a thermocouple on the end of each coil could be used to signal more water into a tube that was getting hotter. Lots of stuff to play around with!
The 60 foot 7/8ths ID Lamont coil in Rod's boiler has about a 5psi pressure drop with about 3000# of water per hour circulated, circulating pump requires 6 amperes@ 12 volts.

Thanks for the detailed info on the Scott-Newcomb, will run some numbers on it with some assumptions to get a rough idea of its pressure drop at 500#/hr steam rate.
If making a "monotube" looking boiler would certainly consider the multiple path approach as smaller tubing of lesser weight with higher gas pass heat transfer would make a smaller package.
Best, George</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Peter Brow (---.public.svc.webtv.net)
Date: July 30, 2002 06:19AM

<HTML>Hi Terry,

Thanks for the info on your experience with the Dick Smith boiler design. The control tuning sounds similar to procedures I am planning for my control system. I think/hope that the controls I have designed will avoid unstable oscillation. I do plan tests to find out the time constant with whatever I end up building, and program controls accordingly. In my system, that would mainly be handled by the fire-control anticipating routine/subsystem. The planned water control is non-thermostatic to avoid thermal lag and has a unique design. Oops, need to keep quiet about that. :)

Pix would be great! Until John's gallery is up & running again, I could drop a few pix temporarily on one of my web pages for folks to look at, if that is OK. Limited space, but I can publish it quick. Do you know anything about the smaller Dick Smith boiler design I mentioned in my last post to George?

Peter</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Peter Brow (---.public.svc.webtv.net)
Date: July 30, 2002 06:56AM

<HTML>Hi George,

Thanks for the tips; always much appreciated. I have sketched multi-piston pumps, but whew. There are some fabrication advantages, though. As is, the paths are all identical, with curious radial symmetry, and steam/water flow resistance should be identical. Flameholder burner was selected to give even radiant heat & gas distribution. One possible bug, besides scale & tube dents, is uneven gas flow due to exhaust flue location; may have to go with annular flue & deal with larger boiler diameter. Don't want to duplicate the Doble-Detroit "fun" ("thermal shorts" per Jerry Peoples).

Wish I knew the coil diameters in Scott-Newcomb; maybe I'll break out the dividers and do some scaling of picture, pref with a xerox enlargement. Probably around 20-22" dia.. Coils are so similar in diameter that it should be easy to estimate equivalent length. Might be in that Wetz article.

Multipath Lamont speculations: 22 circuits of that 1/4" tubing would give same internal flowpath area as Rod's 7/8" ID. Each 60' long, about the same pump hp. Weight maybe 1/3 to 1/4 that of bigger tubing. Easier to bend, more compact, and cheaper/sqft too. 8 is fine for economizer. Extra radiant heating = smaller/lighter than my design, even with drum? Nested helix barrel coils? Size drum as needed for stored energy; doesn't have to be minimized. Tube ends expanded into flanged/bolted drum heads? Or tie rods -- good for 2000 psi+ hydraulic cylinders? Pump impeller inside bottom of drum with multiple outputs around it & blowable scale trap above? Hmm...

Great thread!

Peter</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Terry Williams (---.potc.net)
Date: July 30, 2002 08:26AM

<HTML>Peter Brow said:

"I have read that Dick Smith built a successful(?) small monotube with 1/4" tubing. I seem to recall a photo of him with the small tube stack in his lap; it looked like a loose coil of large-diameter wire. Does anybody know more about this design?"

It sounds llike Richard Smith's version of the model steam airplane boiler designed and built by H. H. Grove, I believe, around 1912. This is described in the Book "Experimental Flash Steam" By Benson and Rayman.</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Terry Williams (---.potc.net)
Date: July 30, 2002 08:31AM

<HTML>George,

I couldn't find photos of the boiler in my computer so rounded up the original photos and scanned them. Tried to send them to you but I don't have a good e-mail address for you, the daemon mailer kicked them back. If you could get me your address, I'll get thim off to you. tw</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Jim Crank (---.dsl.snfc21.pacbell.net)
Date: July 30, 2002 10:06AM

<HTML>Peter, George, Terry,
Multipath is certainly a well proven design. Besler did a few, the Yuba tractor had a five path in the wet zone with each pump cylinder feeding only one circuit. Lear, my race car boiler, had 18 finned tubes in parallel in the economizer zone, square layout with headers, down to one in the superheater. No problems at all. They wanted variable velocity as it went from water to steam.
Broebeck use several in the economizer.
Doble used 5/8 in the economizer, then to 3/4 and on to 1-1/4 for the superheater. If you want more water capacity, then start with 3/4.
The Smith boiler using 1/4" tubing was for a bicycle engine. The car one I had went from 1/4 pipe to 1/2 pipe, concentric design.
Saab used dozens in parallel for their car generator design; but almost hypodermic tubing, fatal with any crud in one circuit.
Multipath and finned in the economizer and wet steam zones, two for the Lamont coil, then into the Lamont drum and one for the superheater. It has to be optimized for the flow rate and output of the specific use.
Jim</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: George Nutz (---.worldpath.net)
Date: July 30, 2002 10:10AM

<HTML>Terry,
Thanks for the pictures, they came thru the second time. Beautiful job. Also thanks for your e-mail address, sent you an e-mail this AM with my e-mail address but it appears you already have it!!
Best, George</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: peter heid (---.netheaven.com)
Date: July 30, 2002 02:47PM

<HTML>In the thin little Brittish spy book from around WW2 about the state of the development of steam transportation in Germany, there is a brief discussion of a multi-path steam generator using a pump for each circulation leg. I forget the name of the "Kirk Michael" book and the manufacturer but it can be looked up easily. Sounds a bit complex to me, I like the single or dual pump with flow restrictors to provide the correct circulation for each leg. Dual pumps were often used with one being electric and the other steam powered. If the electric failed with no steam pressure the boiler was shut down for pump repairs and if no troubles occured, pressure allowed the switch over to the steam powered pump. If that were to fail under pressure, the electric could be switched back on. Quite often though, Lamont installations included only one pump and failures, quite rare.

Can't believe we have kept a continous boiler only thread for this long.

Peter Heid</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Terry Williams (---.potc.net)
Date: July 30, 2002 03:04PM

<HTML>Peter,

Concerning flow restrictors. I like flow dividers better, that way if you get incresed backpressure in a path due to more boiling, you don't get decreased flow in that leg.</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Pat Farrell (---.tnt2.mount-vernon.wa.da.uu.net)
Date: July 30, 2002 08:37PM

<HTML>Dear Terry, Could you please describe a flow divider and how it differs from a flow restrictor? SSsssteamer</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Terry Williams (---.potc.net)
Date: July 30, 2002 08:58PM

<HTML>I think there are several ways to make a flow divider, but the one I designed for a project was like 2 gear pumps with the shafts connected so they both turn together. Put the input fluid into both and direct each output to a different path. This can be all made in a single casing and can be made with more than 2 outlets. If the rotors are the same length, the flows in each path will be the same. Could be made to direct more to one of the paths too. Those more familiar with hydraulics can probably come up with more ways to do this.</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: Peter Brow (---.public.svc.webtv.net)
Date: July 31, 2002 01:43AM

<HTML>Correction. I wrote:

"As noted, once-through multipath design is an untested & purely experimental approach which I am not recommending. It is just something I am personally considering trying, to see if/how it works."

Should read: "... MY once-through multipath design ..."

Typo.

Thanks, George, Jim, and all for the notes on previous successful multipath once-thru boilers. Their success, and the possibilities with this design approach, are what keep me working in this direction.

Jim: good ideas for the multipath Lamont.

Peter</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: peter heid (---.netheaven.com)
Date: July 31, 2002 08:59AM

<HTML>The flow restrictors I have seen on lamont installations also act to filter the water so no larger particles can travel through the coils and possably lodge there. They are also designed so the particles will fall from the restrictor and each restrictor is sized for the fluid friction that must be overcome to provide the correct flow rate for the optimum performance of that circuit. More complex with a flow divider.

Peter Heid</HTML>

Re: Boiler Discussion Thread/Boilers only-
Posted by: George Nutz (---.worldpath.net)
Date: July 31, 2002 10:23AM

<HTML> Remember in a Lamont you do not want necessarilly equal flow in each parallel circuit, you want 5-6 times the evaporation rate of each tube to protect it, Lamont had many boilers that had vastly different path lengths and or heat transfer input.. The same thing would apply to a "multimonotube", the amount of water for each tube is dependent upon its evaporation rate---pretty hard to do when your circulation ratio is zero to 2 or 3 with an on/off pump. Restrictors or any impedance in the Lamont coil(s) create a larger circulating pump pressure and horsepower and should be avoided if possible. Also remember that in the purely radiant section the amount of head absorbed has nothing to do with tube diameter so small tubing has no benefit over larger tubing in BTU's/Sq. Ft/hour.
Off topic I talked to our great Coburn Benson/Ben who has not posted in a long time and was concerned that things were alright with him, really miss his Maine humor and spelling witicisms(make words as short as possible and stuff) plus his depth of knowledge. He is fine, said to tell you all that as soon as he can get his computer past the DOS black and white page will be back, he hasn't had it running in over a month. So Hi" from Ben!!</HTML>

More Bonecourt
Posted by: Peter Heid (---.netheaven.com)
Date: August 04, 2002 06:43PM

<HTML>George et al,

I have found only 3 references to the Bonecourt boiler in the books I have collected. The first 2 only barely skim the surface. The books indicate the design is the work of two individuals and the name is a compound word derived from the inventors names. First being introduced around 1909 and fired on gas. The manufacture of Bonecourt boilers continued until at least 1948 by Messrs. Town Gas Boilers (Bonecourt) Ltd. of London. Bonecourt boilers are compact in size and can be fired in the vertical or horizontal positions. If sufficient draft is not available from stack height, a exhaust fan is included. Each boiler tube contains a spiraled iron core which acts as the refractory and causes a spiral flow of the combustion gasses and intensifying the heat scrubbing action. It is said that the iron cores do not break down like refractory packings used in earlier versions. Each tube has its own gas feed and pilot light with a snap action regulator to provide full or no gas flow for proper combustion. The gas regulator for the burners had a patented "pressurestat control" that maintained the steam pressure to within +/-1.5 PSI and to meet the demand for a steady output steam generator, special modified burner was supplied.

The Steam Boiler Yearbook and Manual IV, Paul Elek Publishers Ltd, London, 1948, had this to say about the Bonecourt:

"The simplicity of design and operation renders both the vertical and horizontal types of Bonecourt boilers and heaters eminently suitable for all purposes where steam at a constant pressure and water at an even temperature is required, especially as the makers state that no supervision is wanted and no labor entailed other than lighting-up or extinguishing, and maintainance is reduced to a minimum." also "... fired by means of a seperate jet into each boiler tube. This provides a large heating surface, giving a high evaporative capacity and quick steaming from cold, for boilers which are very compact in size."

It would seem a horizontal version of the bonecourt could be assembled in modular fashion using the circulation and drum design of a Lamont, and make steam power an easier proposition for designs of limited vertical space.

Peter Heid</HTML>

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