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Lamont boiler

Posted by dullfig 
Re: Lamont boiler
February 01, 2012 10:35PM
barts Wrote:
> Musing things over, it's almost as if the Lamont
> boiler wants a turbopump w/ a electric motor to
> start things off... once the exit velocity from
> the coil becomes many times the entrance velocity
> (which is what happens when the quality of the
> steam goes from 0 to 10 or 20 percent), the coil
> could run itself w/o external power since we could
> tap a bit of the kinetic energy of the existing
> steam/water mix.
> I don't know how to build such an animal, but it
> has its attractions...

Yup--I've been thinking the same thing. It seems like a properly designed steam-driven injector would provide the necessary flow, and the energy thus employed would be retained as a heat rise in the circulated water.

Lots of info, just google for it: [en.wikipedia.org]

OTOH it seems a little like picking one's self up by his own bootstraps, so to speak. Probably not, the energy at the top of the coil stack is much higher than the bottom end. Locomotive technology used the steam (Penberthy, etc) injector for many years as a primary source of feedwater introduction into their boilers.

Love to hear some expert opinions about this.


Edited 1 time(s). Last edit at 02/01/2012 10:40PM by Bill Hinote.
Re: Lamont boiler
February 02, 2012 12:09AM
The trick with injectors is that they have a narrow working range in my experience.... but it is an interesting idea.

- Bart

Bart Smaalders [smaalders.net]
Re: Lamont boiler
February 02, 2012 01:27AM
Hey Bill,

I'm far from an expert, but for the steam injectors to operate the liquid must be relatively cool.

Lindsay publications has a really great little book about steam injectors, well worth picking up.

You may wish to look up Sir Hiram Maxims assisted circulation boiler. It passed the plunger pumped feed water through a spring loaded variable opening nozzle(injector) in the downcomer of the boiler. He had the spring set so that it maintained around a 30 psi greater then boiler pressure on the feed water at the nozzle. This high velocity stream transmited a good deal of energy to the stream of water in circulation in the downcomer. Thusly he was able to use a great multitude of 3/8" copper risers, which produced a shield around the fire and zig zaged back and forth above it for convective heating, economizer above the horizontal water drum at the top, two bottom headers.


Caleb Ramsby
Re: Lamont boiler
February 02, 2012 05:55AM
Relatively is the key word there Caleb. It needs to be well below the saturation temperature, to avoid evaporation, acording to what my theodynamics book says.
Re: Lamont boiler
February 02, 2012 06:13AM
Problem is, sometimes, that we end up looking at what is done in the field we are interested in and aren't aware of what is happening off to the side. I might as well point out that the whole concept of using something like an injector to provide circulation is well established in the nuclear reactor field.

The basic device is known as the 'steam thermopressor' and is descended from the 'aerothermopressor' which was developed to improve compressor efficiency in gas turbines. Typically you pump feed water through a nozzle at well over boiler pressure in order to achieve a high velocity (after about 150 psi the water appears to have reached a critical velocity and further pressure inputs do not seem to add to the velocity). The fast moving, cold, pressurized water pasing through the nozzle enters a jet pump housing wherein it entrains steam from the reactor discharge, condensing it.

The condensation causes a huge drop in volume, creating a corresponding large pressure drop, which causes more steam to accelerate into the area. Naturally, the steam is also entering the jet pump housing through a nozzle, usually being coaxial to the feed water nozzle. The large pressure drop is sufficient to accelerate the steam to Mach velocities, far in excess of the feed water velocity. So we have a weird 'Pushme-Pullyou' effect where the water draws and entrains the steam, which causes an acceleration of the steam which further accelerates the feed water stream.

This combined high velocity feed water/condensate flow passes into yet another jet pump where it entrains water in the primary circulation loop, accelerates it, and pumps the whole mess through the reactor. The circulation flow is now the feed, plus the recirculated condensed steam, plus the boiler water entrained in the resulting high speed jet. This approach is also sometimes referrred to as the 'steam cooled reactor'. In 1000 psi reactors, I have heard of pressures as low as 200 psi in the thermopressor nozzle due to condensation of steam, suggesting that the steam flow is truly at critical velocity. Actually, this is far beyond the critical pressure and I speculate that perhaps more advanced designs with more effective mixing might produce a smaller pressure drop in lieu of a higher pumping ratio...but that's just my speculation.

Anyhow, I have been doodling around with this design and suspect it might work just fine in an automotive forced circulation system.



Post script. Sometimes I ger really weird and observe that boiling water nuclear reactors look a bit like a Stanley type boiler in that both have hot, vertical tubes surrounded by water. Big difference is that the nuke circulates the water vigorously by using mechanical pumps, thermopressors and the like....and thus can operate at higher heat flux. Would probably be interesting to see how hard you could push a vertical firetube if you had a pump and provisions to direct flow more efficiently.

Edited 1 time(s). Last edit at 02/02/2012 06:36AM by frustrated.
Re: Lamont boiler
February 02, 2012 12:57PM
Hey Ken,

The Velox, in most of the designs I have seen at least, used a horizontal firetube, with superheaters inside the flues, they were pushing that thing like crazy!

Caleb Ramsby
Re: Lamont boiler
February 02, 2012 02:34PM
Just to consider that this discussion started off for a very high output and small Lamont for auto use. Unlike other applications the auto has the greatest demands,sudden changes of output than any other application. The injector circulation may be useful for larger more constant load boilers that have a longer time constant but in an auto guaranteeing sufficient circulation under all conditions all the time is a serious matter to keep in mind tube burnout can occure in a matter of seconds. Back a ways we discussed the International Harvester railcar Lamont and it started off with an injector for the Lmont circuit but believe in an article you came up with(thank you!) they gave up on it because of the requirement to replace tubes. I have done the complete heat transfer on that boiler with its 56GPH? firing rate and the inner Lamont helical coil is taking the most intense heat transfer in the whole boiler and would oonly be protected with a constant high circulation ratio. I analyzied ever foot of tubing in that boiler and came out with analytical results very close to the claimed performance. Takes a lot of time to do that but it is one way to sharpen ones skills in doing boiler heat analysis. I do not see the any requirement to get rid of the 1/10HP circulating pump that would satisfy the 12GPH Lamont designed for Jim Crank. But then I am getting old and fixed in my ways, good fortune to anyone coming up with a superior solution . In that design the helical Lamont coil was very safe at a heat transfer rate of over 40.000BTU/sqft/hr.
Always appreciate your messages and knowledge, George
Re: Lamont boiler
February 03, 2012 07:14AM
Hi George,

The International Harvester/Ryan railcar system that you referred to had, what I consider, to be a fatal bug, the flow into and out of the separator drum was not tangential. Water entering the drum from the circulation loop almost immediately lost all velocity due to turbulence, which made continuous forced circulation mandatory. Based on my experience with eductors of very, very similar design and relative admission pressure, I'd figure a pumping ratio for the feed water circulator at about 1 pound pumped for every pound admitted. By contrast, thermopressers routinely provide sufficient circulation for 1000 psi nuclear reactors, indicating a much higher circulation ratio...probably about 5:1 or better. There were a few other problems with the IH/Ryan system from which I think we can learn.

As noted in other posts (above), the circulating flow in the coil(s) increases in volume as part of the saturated water undergoes phase change, significantly accelerating overall flow and being essentially independant of the pump. This phenomenon can be exploited in at least two ways: by avoiding stagnant zones that promote velocity shedding and separating the steam from the water in such a way as to promoote beneficial momentum transfer, this being not-uncommon in vortex separators. Even if heat-driven flow is insufficient to sustain full circulation velocity, proper management promotes a gradual winding down rather than a prompt circulation loss, giving time for forced circulation to restart.The IH-Ryan jet pump is a traditional eductor design which unnecessarily restricts secondary (driven) fluid flow, reinforcing the position that a jet pump tailored to this job is desirable.

I really appreciate the hard work you've invested analysing the forced circulation boiler, it's been a tremendous boost to the concept of the steam automobile. Outside independant sources fully support your prescriptions regarding circulation ratios, and it is a bit of a wonder that they have been treated in such a hit or miss fashion by steam auto developers. My only real divergence is on technical points of implementation, which is unsurprising, despite the massive convergent engineering put into IC engines over the last century there are still often very clear differences in how manufacturers strive to achieve many of the same ends.

The drum is my biggest issue, occupying space which is very dear in a modern engine bay, not to mention weight and cost. Heating that much water increases start up time and the lost heat on shutdown lowers overall fuel efficiency. Very early gasoline horseless carriages had huge flywheels to make up for deficiencies in the powerplant, but the flywheel has become proportionately much smaller as engine power and responsiveness have evolved. Likewise, a rapid firing, high heat flux boiler should be capable of meeting demand without the crutch of a large reserve...which is the route Rollin White took and apparently one of the concepts in the Cyclone. Given a 5:1 circulation ratio, the forced circulation boiler should already have enough saturated fluid in the loop to meet sudden transient conditions, it actually has far more reserve than the monotubes of the 60s and 70s.

I think a 'drumless' system forces discipline beneficial to a thermopresser driven system and is not without merit if using an electrical pump. Eliminating the drum requires the feed flow mass and associated firing rate to closely approximate the steam flow through the engine (this is sounding like something Rollin White would have done 110 years ago) rather than employing on-off control schemes with significant hysterisis. Such close control is advantageous to a thermopresser, the feed driven circulation ratio closely tracking the firing rate avoids significant interruption. We should be just fine if the themopresser can maintain a minimum 5:1 circulation ratio with feed in proportion to the firing. I suspect that, even without a thermopresser, the IH/Ryan system might have done far better if they had used a tangential flow cylconic separator and infinitely variable feed rates.

I've been working on design of a compact unit that functions as a thermopresser and cyclonic separator so as to provide a good recirculation ratio, minimum flow disruption and promote momentum transfer from steam to water...a real eye watering exercise, I grant you. I don't see that the function of the drum can be completely eliminated, but am looking at a small amount of spillover and a small helical holding coil...kind of like a really small Baker coil. The spillover recycles back into the pump via the coil....and a sensor on the coil detects flow and provides finer tuning of the feed water flow...sort of like White using a flowmotor to provide 'almost right' fuel regulation and a thermostat to tweak the final result. I'm envisioning a similar scheme for the fuel flow, it will also be mostly regulated by the steam flow through the engine but tweaked by the pressurestat. Of course, modern vehicles employ TPS (Throttle Position Sensors) to anticipate emergent demand changes and respond accordingly. The controls are purely mechanical, but that is more a reflection of my lack of expertise, mature system would use a mass flow sensor in the steam line (hmmm...might be more practical in the exhaust manifold) just as we do the same with airflow into the intake manifold to regulate fuel flow to the injectors.

I'll readily concede there's a fair chance I won't be able to pull this off, but if I can it should be a very compact and mechanically elegant system. I also question whether, given the rapid adoption of turbo and supercharging in almost every line of IC engine, whether anything less can even stand a chance in the market. And, Hey! If nothing else, looks like it will all be fun.



Edited 2 time(s). Last edit at 02/03/2012 12:31PM by frustrated.
Re: Lamont boiler
February 03, 2012 09:25AM
Hay Ken. One thing you didn't mention is sediment. One of the functions of the
drum is to allow for solids to separate out and be able to blow down the steam
generator. Or you need to go to using very pure deionized water like Harry.

But still one thing that bothers me about this separation scheme over a plain
mono-tube boiler is the output range required by the power range required by a
modern road vehicle. With a fixed super-heater length on the LaMont and other
types of boilers with a fixed super heater length I am not seeing anyone claim
more then a 5:1 output range with a consistent output temperature. There is of
course a limit to the turn down that the burner can provide.

A lot depends on the engine design. But the thing is that too high a superheat
results in waste heat in the exhaust lowering efficiency. And a low superheat
results in condensation in the engine lowering the efficiency. And extremes
on either side can damaging the engine.

With the expansion ratio of the engine constant and ignoring acceleration
requirements. Steam usage varies with the cube of the speed. Say for
simplification that below 20 MPH we are below the speed = F^2 law of
aerodynamics. It kicks in between 15 and 20. Say we design for 80 MPH top speed.
Then from 20 to 80 we are in the square law range. A 4:1 speed range. The square
law combined with distance traveled over time makes it a cube relation to power.
and steam rate is basically power. So from 20 to 80 you have a 64:1 steam rate
variation. Say that the lowest continuous speed is 5 MPH. Then from 5 to 20 MPH
a 4:1 speed range where speed = F a linear relation is a square relation to
power or steam rate requirement. That makes for a 16:1 steam rate 5 MPH
to 20 MPH and a 64:1 steam rate 20 MPH to 80 MPH for an overall steam rate from
5 MPH to 80 MPH of 1024:1 steaming rate. I doubt this range can be achieved. and
to be fair an IC vehicle doesn't achieve that with out a transmission combined
with friction losses. Some high performance cars can not achieve that kind of
range. My Stealth with a 190 MPH top end could not go below 30 MPH idling in low

The White steam generator is the only one documented to be able to hold
consistent steam temperature over a descent range. But it spiked at times with a
sudden drop in demand. I don't think it would be much of a problem as it was for
a vary short duration that the engine would be exposed to excessive superheat.

Re: Lamont boiler
February 03, 2012 12:42PM
As I am of the old school(and getting tired) I am still happy with the classical LaMont design with external circulating pump and a seperating drum with tangential input and outputs. I do not know much about eductors but if you can always gauaranty an adequate circulation ratio from start/high/low/no output then I would applaud yoou greatly. All three of my designs of course have the tangential "cyclone" operating principal as it adds head pressure to the circulating pump input and that is very beneficial as the chance of pump cavitation is eliminated and the horsepower required to get the 5:1 flow ratio is reduced.
I really think the drum is a great idea if there is room for it as it adds a large reserve overload capacity to the boiler if it contains 20+ pounds of saturated water at temperature to draw off of. It greatly simplifies the control system and allows a longer time period for the feed pumps to get water back into the drum. As we are talking about an additional 20K BTU added to fire up time and loss overnight it is not considerable. From memory I believe Teel's LaMont firing at 5gph took about 2-1/2-3 minutes to fire up to 400psig pressure. Slower than a light monotube but in all other respects superior. The greater the specific volume of the mixture in the LaMont section of course the greater the velocity and all other things being equal(same G-mass flow etc) then the pump backpressure is mainly dependent upon the specific volume in that foot of tubing. The Reynolds Number does effect the backpressure but to a much smaller degree as the friction factor goes down(and Reynolds number goes up) as the mixture viscosity goes down.
The viscosity of saturated water@400psi is about .25 and of 20%SBW about .07. Again the velocity/specific volume in each foot or coil should be calculated to get its individual pressure drop-doing this requires calculating the heat input of each foot/coil considering radiation/convective and intertube radiation for that particular coil. Using an average is a first guess but not totally accurate as Caleb has done. This can be exhausting work if one has to use formulas to determine every mixture specific volume and viscosity so 30 years ago went thru all the theoretical equations so I could plot out on the B&W graph the absolute viscosities of various % mixture by weight (and volume) for several vertical pressure lines, think in my book the graph is on page8-14. It certainly cut down the longhand time back then of doing each one by equations!
I am not up on modern controls as you are but often thought of a variable speed blower for the fire(with a Fish very fine mist carburator) also driving the LaMont circulating pump, getting rid of the on-off fire and just having it modulate according to demand. Thus as the steam demand went up the pump would recirculate more. As there is residual firebox heat to be soaked up after the fire goes off it would be nice to have the Lamont circulating pump contine for possibly 10 seconds. We experimented with this on the Teel boat LaMont in a manual/ experimental way.
It is a joy to discuss this with you with your considerable knowledge and I would be the first to raise a glass to your achieving the directions you are persueing, also greatly enjoy Calebs considerable energies on the pursuit of a good boiler, it takes a lot of love and gift for it.
Best, George
Re: Lamont boiler
February 03, 2012 01:06PM
Hi Andy,

In 24 years with the Navy and Reserves in shipyards around the world, I only saw one boiler that suffered from excess sedimentation. As I understand it, the Chief Engineer and a few other top departmental officers did time in Leavenworth, the Captain's career was ended, the senior enlisted were imprisoned, demoted, ejected or transferred depending on degree of culpability. The upper end of the chain of command literally disappeared and replaced...think of it as affirming the importance of good feed-water chemistry. Provisions can be made even in rapidly circulating systems to separate and trap minimal amounts of sediment that might occur, but in a modern system it shouldn't be a driving design factor.

I think you have over-thought the issue of separation and power range. If running at 1 mph, the steam generated per square foot of tube is so small that we will never reach DNB, a circulation ratio of 1 is perfectly satisfactory and we really don't much care what the flow velocity is because the burner can't supply enough heat at that speed to do any damage. Now, if we fire like mad at full power and then shut it off to coast, there might be problems although even then I am not sure that you could harm anything before the steam overproduction shut things back down. This holds true for a whole range of vehicle speeds up until we reach the point where speed is finally high enough to demand a heat flux which is too high for a once-through boiler, hopefully by this point we'll have some recirculation kicking in. I don't really see this being an either-or circumstance, it isn't like you need to instantly jump from a circulation ratio of 1:1 to 5:1, you just need enough flow to prevent DNB at that given heat flux.

With a fixed length superheater, the potential for convective/radiant elements and the possiblity of active temperature control via desuperheating, I don't think any temperature spikes in the White steam generator at all translate to the same happening here. I probably should have been more clear, when I referred to White I meant that he would have been extremely comfortable with controlling a forced recirc boiler by proportioning fire and water to demand and then performing secondary adjustments based on different measurements, the control scheme is necessarily a bit different than his and would require a bit different hardware and yield very different operating characteristics.


Re: Lamont boiler
February 03, 2012 01:30PM

One of the cool aspects of the Lamont type is that the firing rate can be modulated instead of being just on/off. The feedwater control is a completely standalone issue and should be able to deal well with different firing rates.

An easy way to work with this is to have the propane valve (I'm planning on using propane BTW) swing on the same linkage as the steam throttle so it responds directly to steam usage. The use of an overriding shutoff (either mechanical or a solenoid) would still be appropriate for the burner control to prevent overpressure. Also, a manual bypass circuit should be included for startup and/or unusual operating conditions.



Edited 1 time(s). Last edit at 02/04/2012 01:33AM by Bill Hinote.
Re: Lamont boiler
February 04, 2012 06:05AM
Hi Ken

The sediment issue and power range are seperate issues. I am not sure exactly what George did with tangential flow into the stand pipe. But as I read it, the stand pope allowed sedement to colect in the bottom so a blow down of the standpipe took care of it. Jim has commented on this as well as in the doble it was where super heating started that the sedement would drop out and coat the inside tube wall causing burn out. So the stand pipe took care of that probablem. But with a tangential flow the swirling would tend to mix sediment into the fluid expecially in a short tube as you described. The tube height I think would effect the sediment seperation. With the tall stand pipe and the inlet at the upper liquid level I don't think there would be a probablem. But if you reduce the volume to much and have a very short stand pipe you might wind up recirculating a sludge. Maybe not a problem but a thought. Just following Murpfy's Law.

The steaming rate range to speed range requirements has to do with delevering consistant steam to the engine such that you would not be wasting heat out the exhaust with to high a temperature or condensation occuring in the engine. And in an extream to high a temperature could damage the engine. Corbonize the lubracant for example. And to much consensation in the cylander can lock up the piston and blow the head off or bend conecting rods etc. With a seperator stand pipe I don't see as much a possability for condensation unless you have a very high expansion ratio.
Re: Lamont boiler
February 04, 2012 11:17AM
It isn't sediment that deposits out in the Doble, it is carbon formation right around where the normalizer nozzle is placed. At and around where the transition zone is from dry to superheated steam. Occasional hard blowdown from both ends is done in a Doble, just like in a White.
If a new car were to be constructed, the usual cylinder oil would most certainly not be used. Water lube for the piston rings. Clean water in any case.
Sediment separation in the Lamont drum is insured by using the correct baffles inside. Same as the ones on the top prevent a sudden throttle opening from picking up water and tossing it into the engine.
Superheat stability is accomplished by first of all burying the superheater a bit down from the fire in a Lamont. Then dimensioning it so that it delivers the right temperature. Then using a simple normalizer to catch any swing.
The circulating pump could possibly be part of the blower-draft booster assembly so flow rate goes up when the firing rate goes up.

Anybody know why Goggle has now infested our opening page for this site?
Re: Lamont boiler
February 06, 2012 06:10AM
Hi Jim

Thanks. I misremembered you comment on that. I can see were oil would be a
problem. But how is dissolved solids taken care of in a Doble steam generator.
I thought you said somting about blowing it down.

I was applying Murphy's law to Ken's idea of a low volume separator idea. In
the LaMont sediment collects in the bottom of the stand pipe. Ken did not address
sedimant colection in his description.

Re: Lamont boiler
February 06, 2012 08:09AM

Sedimentation doesn't occur spontaneously, it must be introduced. The options are to handle or avoid it. Antique cars are forced to replenish often, making water chemistry control problematic, this should not be the case for a well maintained, modern system. Clean water and good water treatment avoid problems.

Re: Lamont boiler
February 06, 2012 09:10AM
Hi George,

Steam systems make me a bit schizophrenic because I am building one as a hobby, with all the design latitude that offers, but work in automotive powertrain engineering and am often acutely reminded of the current advanced state of powertrain engineering and the demands emerging from regulatory processes, fuel prices, customer preferences and competition. I readily grant your position that the drum provides the reserve to make control simple with accompanying peace of mind...which is why my working drawings still show a large drum.

I more recently approached the matter from a commercial aspect and asked: "If I were to propose development of a steam car, what horsepower would I specify and how much engine bay volume could be allocated profitably?” The short answer is that no currently extant or proposed system seems viable. Forced circulation gives high heat flux density that reduces the boiler coil size. but the drum seems to wipe out that advantage with no LaMont actually looking more compact than the Carter, Barrett and SES monotubes. Erasing the drum makes the situation more favorable. So, I guess it's all a matter of which direction you approach the matter; as a steam car guy who wants a pleasant hobby steamer or as a car guy looking to deliver something that meets emergent regulatory, economy and competitive demands.

The valuable LaMont analysis you have so graciously shared (and for which I am very grateful) makes me realize that not only is the potential heat flux higher but, even without the drum, the reserve exceeds many monotubes. It seems to follow that if monotubes are more-or-less controllable, then the higher reserve of a rapidly recirculating drumless coil should be a bit less difficult...my estimate being that it all comes down to a very good separator and tight feed control. Beyond the boiler, the engine must be compact and efficient; since short cutoff and compactness are contradictory, higher rpm seems indicated. Jay Carter required two huge surface condensers, probably validating the need for direct contact condensers. The typical steam car rats nest of auxiliary systems is a serious problem begging more attention. The whole system needs packaging and repackaging to fit into the smallest cube on which periodic maintenance can be performed.

Might be the modern commercial automotive steam powerplant just isn't practical, in which case there is no reason to contemplate ditching the drum. But for the moment it has been a very interesting exercise.

Warmest Regards,


Edited 2 time(s). Last edit at 02/06/2012 09:36AM by frustrated.
Re: Lamont boiler
February 06, 2012 10:33AM
Most Dobles that I have had my hands on, eight now, all were fitted with scale traps between the superheater outlet and the throttle.
You waited until no one was behind you then lay on the foot operated blowdown like mad. This seems to keep the crud out.
Then about every two years or so, as Barney did, you hook up your compressor to the inlet, oxygen tank if you are really brave, jamb the temperature control contact open and run the tubing up to a good high temperature, open the blowdown valve and let her fly. Clouds of red smoke, sparks and fire and it really cleans them out.
White owners use the blowdowns on both ends of the coil stack, as the Good Book says, and blast away after every trip. I did and it seemed to keep the car happy. I guess it worked because my OO was running on the original coil, some 75 years later. That is good enough for me.

Ken, Truer words were never spoken.
"The valuable LaMont analysis you have so graciously shared (and for which I am very grateful) makes me realize that not only is the potential heat flux higher but, even without the drum, the reserve exceeds many monotubes. It seems to follow that if monotubes are more-or-less controllable, then the higher reserve of a rapidly recirculating drumless coil should be a bit less difficult...my estimate being that it all comes down to a very good separator and tight feed control. Beyond the boiler, the engine must be compact and efficient; since short cutoff and compactness are contradictory (Not really), higher rpm seems indicated. Jay Carter required two huge surface condensers, (Remember that heat of vaporization) probably validating the need for direct contact condensers. The typical steam car rats nest of auxiliary systems is a serious problem begging more attention. The whole system needs packaging and repackaging to fit into the smallest cube on which periodic maintenance can be performed."

One reason for the Lamont fascination is that even with a draft booster going full tilt, the late E and F Dobles got around 26-28 lbs/sq/ft/hr, while a fierce Lamont can deliver over 50 lbs/sq/ft/hr. The monotube has some tricky control problems only really under full control with two stage water feed rates and a normalizer to catch any wild swing and depending on thermal inertia to cover things in between. The Lamont only wants good water level control and the usual pressure fire cutoff. Most important besides the reduction in size and weight, is the drum, which is not all that big, now gives a hard fired essentially monotube, a good reserve. Tack on extended surface tubing in the economizer and boiling zones and as one believer, I don't know of a better solution to this steam car dream we all have.
Then there are the juicy what ifs, like anticipating firing rates, Lamont circulating pumps with variable flow depending on the firing rate, heat conservation like the Cyclone with that variable clearance volume actually inside the fire box, balanced single seat inlet poppet valves. The wish list goes on forever.

Then, watch Jay Leno's video of his Stanley Vanderbilt. Pure hair raising fun and isn't that what most of us want, in all honesty over saving the world from it's follies?
Re: Lamont boiler
February 07, 2012 12:34AM
I was mulling over Lamont boiler tubing/piping layouts when it occurred to me that since the coil is essentially all at the same temperature, there's no particular reason to use a counterflow model - indeed, it would be best to have the final part of the coil furthest away from the fire, since that part of the coil will have the lowest heat transfer rate.

Does this make sense?

- Bart

Bart Smaalders [smaalders.net]
Re: Lamont boiler
February 10, 2012 03:27PM
As the inside film temperature drop on the LaMont circuit remains almost constant on temperature differential it really does make much difference if it is started off parellel flow or counterflow. The entrance tubing is nearly as well protected with 100% saturated water as the exit from the circuit at 80% WBW. So it appears that the LaMont circuit can be used in the hottest heat transfer sections of the boiler with great safety if the circulation is maintained.
Good luck, George
Re: Lamont boiler
February 11, 2012 03:11PM
Have some thoughts concerning the Discussed boiler..
Here a rough sketch of my ideas.The main principles is a La Mont boiler with a stand pipe and forced circulation..
Like to have the entire boiler full of water at pressure of say 140 bar, feeds a preset pressure feed waterpump,,,
the Burner is set to stop warming after about 300C, that temp equals a pressure of 120 bar,
so the circulating water is just hot 300 C water.. if this water should relished into a space with lower pressure it
immediately Flashes into steam..
The Throttle regulates hot water to into a pipe that leads to the Final stem produce Superheater coil in the boiler.
That means the desired pressure to the Motor is achived by the amount of hot water are Throttled/regulated into the superheater..
The risk of water into the motor is reduced by a orifice before the throttle, this hole need not to be any larger then the vehicles motors stem
consumption.. Take off´s will be softer as the super heater has to be filled .
If this ideas can be used, means we can forget the water level devises.
The pressures here are random choises to explain the idea, lower or higher presures can work but the higher pressures and temps gives more
heat reserves,,

As you know Sevaral Powerplants today have water pressure up to 340 bars, And Supercritical temperatures up to 550 C.
Have talked to a Machinist at a Plants machine room, then thy shut of the lights they could se the the unisolated parts on the
turbine housing glowing dull red.
Sorry for given the numbers in Metric only

Gratefull for any comments --/+ ?

Thanks Jan S

Re: Lamont boiler
February 27, 2012 04:28PM
I hope it's OK to re-activate this thread:

I've been considering the circulation pump and the heat load it has to endure--and how it might be placed so as to reduce that load.

If I just put the output from a feedwater pump into the standpipe then it mixes with the circulating water and results in a slight or moderate reduction of observed temps at the circulating pump. OTOH if I inject the feedwater near the entrance of the circulating pump and AFTER it leaves the standpipe, then the circulating pump enjoys all the temp reduction the FW supplies to the system.

Question is, how critical is the injection point of the feedwater introduced into the system?

All comments appreciated!

Re: Lamont boiler
February 27, 2012 05:02PM
A very good idea as circulating punp cavitation is alwyas a problem withthe circulating pump drawing off of drum saturated water, Depending upon the economiser input temperature to the boiler it could be usefull to inject the feedwater into the tangential fluted input to the pump input to reduce this possibility. Possibly the feedwater input(sometimes could contain a small amount of steam however) is a very good idea, I would think the input of feedwater should be in the input of this pump intake tube.
Regards, George
Re: Lamont boiler
February 28, 2012 07:57PM
Hi Guys,

A couple of thoughts after reading a bit of the last weeks of this thread; As to the use of a Lamont boiler for lower pressures please look at my condenser experiments. Small though the boiler was, it was a Lamont and the pressure was about 6 lbs gage. It just took a large pumping rate. It worked really slick.

I am thinking that the formula for circulation should be based on allowable steam volume in the tube, not on mass. IE. lower pressure means more saturated steam volume in the tube so faster circulation to clean it out.

Ken, the boiler shape has to fit under the hood and a round shape leaves some hard to fill space, maybe. If the Lamont tank was separated into four tanks, then one in each corner of the boiler would make a more cubical shape which could/might fit better.

As to the recirculation pump; If it were outside of the Lamont tanks then the motor itself could be an induction type and run pressurized in oil. It's temperature then kept at about 200 deg F. A simple piston against the oil would keep the pressure equalized on both sides of the shaft seal. A DC motor might work as well if needed.

Best Regards,

Bill G.
Re: Lamont boiler
March 13, 2012 10:49PM
The copy of Steam Generators arrived a little while ago, and I've been reading that - very interesting. I also ordered and just received a copy of "Steam - Its generation and use" by B &W - excellent. This is the 1955 edition - it is available used via Amazon delivered for about $10 - a screamingly good bargain; I recommend this to anyone who doesn't yet have a copy.

Now to start writing some code to model the boiler. I find hand calculation tedious and error prone in my hands; I'd rather spend just as much time writing and debugging some code to do the same thing cool smiley.

- Bart

Bart Smaalders [smaalders.net]
Re: Lamont boiler
January 31, 2015 07:35PM
I hope it's ok to revive this thread.

It seems the point is to eliminate boiling in the coils. If you put a slight restriction at the exit of the coil, the circulation pump would maintain the coil at a slightly higher pressure, and all the boiling would occur in the drum. Sorry if this was already discussed. Has this been tried?

Without a restriction there will exist a pressure gradient due to friction, but close to the outlet it will be close to drum pressure, allowing boiling in the tube (I think)

Re: Lamont boiler
January 31, 2015 07:59PM
The point of a LaMont is to do as much of the boiling as possible in the circulation tubes via utilization of the radiant heat from the burner.

The LaMonts distinct advantage is that the circulation ratio, as in lbs of water circulated to lbs of steam produced, is under absolute control of the designer under all conditions.

As George Nutz points out many times in this thread it is a 5 to 1 ratio at full fire that one should shoot for. Designing boilers is extremely complex.

A very simple bang together boiler is the late John Wetz's wood fired monotube boiler. He designed it to be made with cheap electronic controls, simple, easy and cheap were his goals. I think that they still have the layout and description of his design in the storeroom, not sure, you may need to call the store keeper. His stuff worked.

Caleb Ramsby
Re: Lamont boiler
January 31, 2015 08:22PM
Yup, you're right. If you prevent boiling, you don't soak up the heat of evaporation. You absorb a lot more heat allowing boiling.

Ok, just a thought, wouldn't it help then to have the circulation pump "suck" instead of "push"? Lower pressure in coils, more boiling.

Re: Lamont boiler
January 31, 2015 08:34PM
Caleb Ramsby Wrote:
> The point of a LaMont is to do as much of the
> boiling as possible in the circulation tubes via
> utilization of the radiant heat from the burner.

Naaahh--can't agree with this!

IMO the REAL point of a LaMont is that it is quite immune to control deficiencies. This means if you make a mistrake in design, or in operational functions--the LaMont saves you because of the circulation.

The bonus is what you have described; take it from me, I have burned up several coils because of design errors in controlling monotubes. I have also (recently) seen the benefits of the forced recirculation boiler protecting the safety of the components.

Bottom line is, when properly designed the LaMont can also be more efficient. First things first then take advantage of the refinements.

Re: Lamont boiler
January 31, 2015 10:39PM
Hey Bill,

I believe that you are defining more the difference between a monotube with its finicky control to that of a water level in general with its much more stable control system. I did an analysis of the time coefficient in the control system between a Stanley and White once as a measure of gauging the difference between monotube and water level boilers, it is worth repeating here.

"That is, a 20 horsepower Stanley boiler(23” od, 14” high having 751 33/64” od tubes) has a total internal volume of around 3,621 ci,(2.09 cf). This volume will vary slightly with the number and size of the tubes, as well as the shell thickness. If the water is carried at 10”, leaving 4” of steam space, there is 2,586 ci(1.5 cf) of water stored. At a boiler pressure of 500 psia the water is at 467 deg F. and has a volume of 34 ci(.0197 cf) per lb. Thusly, the boiler in question holds 76 lbs of water, basically all of it at or near its saturated temperature.

Stanley 20 horsepower boilers burn around 4 gallons of fuel per hour, producing approximately 325 lbs of steam per hour.

So, in one minute that would be 5.4 lbs of water boiled away. The boiler holds 76, so that is roughly 1/14 of the boilers stored water and would be about .7” of water per minute boiled away. If you boiled it down to only 4” of water in the boiler that would be, 8.57 minutes. Normally this is not how things are done and the water pumps are either manually or automatically bypassed to maintain the water level within a much tighter range. If this boiler output could give you 50 mph, that is .83 miles per minute, so 7.1 miles traveled without turning on the pumps. This however is rather extreme, going from the max water content to the min.

This rather great quantity of water allows the boilers control system to be very basic and basic or simple things generally last longer then more complex things.

Speaking of such, Whites using a monotube boiler had very little practical reserve. Just how little, well lets see.

The 40 hp White used 243 feet of .723” od .5” id tubing in their boiler, wrapped up in coils similar to the heating element on an electric stove top, a series of these stacked one on top of another with the water entering the top one and going down towards the fire in an up and over maneuver between each wrap that acted as a water trap, basically a version of the water trap under the sink(minus the strange smells and leaks(hopefully!)).

Ok, this length of tubing would hold a volume of 572 ci(.3313 cf), now lets say that roughly one half of this is straight water and the other half holds superheated and saturated steam along with various proportions of mixed saturated steam and water. The actual quantity of water held in a monotube boiler is a thing of great puzzlement. Depending on the superheated steam temperature, boiler pressure, percentage of capable firing rate it is run at and the beginning water temperature it will vary greatly!

Well, lets just say that the water content is somewhere between 572 ci and nothing!HA!!!

Ok, I will go with half and leave you to your own devices. That would be 286 ci(.1655 cf) of water. At the same pressure of the Stanley that would be 8.4 lbs of water. Now part of that would be rather cold water and part would be hot, then there would be some more that would be part water and part steam(my brain hurts now). Well, 8.4 lbs at least or most.

Now, the 40 hp White burned 8 gallons of gasoline per hour at max and made around 490 lbs of steam per hour.

So that would be 8.16 lbs of steam made per minute and only 8.4 lbs stored or 62 seconds of it going without the pumps on and the boiler is DRY! Actually the steam would be way overheated at that point and be burning the engine oil etc.

So to keep the White boiler within a 5% water content window(thusly if at 500 psia a 25 psi range, since water content dictates a monotube pressure as much or more then the fires intensity), that is .42 lbs range, that is 3.1 seconds of response time."

So the ratio of control response times between the 20 hp Stanley and the 40 hp White is 165.85 times!

The above in quotes is from an article I wrote for the SACA bulletin a few years back.

The LaMont isn't unique in it's ease on water level control, far from it.

The maximum heat transfer rate on the fire side of a water level boiler is dependent on the heat transfer coefficient on the water side(actually it is such for all boilers) with a Stanley with its more then less stationary water, that rate is very low, thusly the warped heads and leaking tubes when they are pushed too hard. The Derr, Warriner, Ofeldt and Baker type are natural circulating and have a much higher heat transfer coefficient on the water side then the Stanley. The advantage of the LaMont is that the circulation rate isn't dependent on the configuration of the tubes, their height, their coefficient of friction, their diameter, their bends, the ratio of downcomer to riser areas and the bends and exit and entrance efficiency of the tubes, to over simplify it a bit, the LaMont circulation rate is dependent on the pumps power, it just jams the water through and there is no need to worry. It also allows for less concern for flow losses in the circulation tubing then with natural circulation. If it is designed just right the natural circulation boiler can be pushed very hard, but doing so produces some compromises in the design and permanent brain damage!


Here is a great book on the history of boiler development:


I remembered a link posted by Brian McMorran about a study of Nature and Artificial circulation, a true gem if there ever was one, used the search engine to dig around and finally found it in THIS THREAD page 12 of it here is the link:


All of your questions about boiling in the risers etc. are answered in the links above.

Caleb Ramsby
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