UPDATE, 5-18-2004: The new boiler design discussed below has recently been changed to use 3 spiral "pancake" tube coils, instead of 3 helical "barrel" coils. The "pancake" coils, which look like giant clock springs, are harder to bend than the barrel coils previously considered (& discussed below), but they allow the boiler to be more compact overall, and they allow use of a more conventional "premix-vaporizing" burner with less chance of coil sooting. I have also decided to use a finned top coil (economizer) to cut boiler weight and size. I found a relatively easy and cheap way to make my own finned tubing! Sooting can be a problem with finned tubing if the burner malfunctions, but I think that my burner will be easily maintained to avoid sooting, and the type of fins I plan to use should be easy to clean if they do soot up

I am now constructing the pilot light and a downsized test version of the main burner. The pilot burner, closely based on the road-proven Stanley steam car pilot, is very nearly finished, and a greatly improved main burner construction has been blueprinted.

Digression

Recent increases in gasoline prices have led to increased interest in alternative fuels and alternative vehicle powerplants, and also increased visits to my web pages and more e-mails. My thanks to all visitors for your interest, suggestions, and moral support! Between the extra email traffic and increased drawing board and shop work, I have had trouble keeping up with inquiries, so my apologies for delayed replies. The burner I am presently working on should handle gasoline, gasohol, kerosene, diesel, and biodiesel without problems, and should be easily adaptable to burn hydrogen, natural gas, propane, and alcohol fuels. I also have ideas for solid-fuel burners which can cleanly burn wood/cellulose pellets, coal, and desulphured/demineralized coal dust (an abundant, economical fuel which is much cleaner than it sounds!). With the Lamont boiler design, I believe that burner controls should be easy to develop for any of these alternative fuels -- and as noted elsewhere on this website, steam cars can run beautifully on any of these fuels!

If you are concerned about the future fuel situation, as I am, then check out the article (with many links for further study) at http://en.wikipedia.org/wiki/Thermal_depolymerization about "Thermal Depolymerization" (TDP). This is a simple new technology which economically & efficiently converts garbage, agricultural & landscaping waste, sewage, or any other organic material, into high-quality crude oil, which can then be refined into any petroleum product (including gasoline) in existing petroleum refineries! Since the carbon in them comes from the atmosphere, oil and oil products from this process do not contribute to the "greenhouse effect" or "global warming" which some scientists believe may be occurring due to use of fossil fuels. I think that this proven yet media-ignored technology may very well be where most of our future fuel will come from. Instead of pumping Mother Nature's oil out of the ground, in the future we may make all the oil we need from abundant organic waste materials -- and/or from plant material farmed for fuel purposes! In the future, every farm, sewer plant, and trash dump may become an endless renewable oil well!

Imagine vast fuel farms, watered by solar-desalinized seawater, spreading across the barren deserts of the planet -- or vast floating kelp farms on the open oceans, generating many times more oil than we use today! Such things may seem impossible when viewed from the perspective of today's media-generated "disaster mentality", but the human race has already transformed the world in many wondrous ways, by setting aside the perennial bugaboos of conflict, zero-sum thinking, negativity, and fear of changes, limitations, and shortages, and putting to work the amazing powers of science, productivity, and creativity!

Whatever fuel or energy situation arises in the world of the future, it is my belief that the clean, versatile steam automobile will one day play a major role in providing fun, pleasant, affordable, and practical transportation for millions of people.
(Tuesday, May 18th, 2004)

Wednesday, February 11th, 2004

It has been a while since I last updated this website, so I figured I'd write up a short report on the progress of my steam car project.

The Big News is that I have changed the design of the boiler. Actually, the boiler design has gone through several changes since the multi-circuit once-through design noted elsewhere in this website, and none of those changes were documented here. That is probably not a bad thing overall; why waste visitors' time with several generations of drawing-board changes which never made it to the shop?

The boiler changes are sort of a "good news/bad news" thing. The bad news is that every boiler design which I've worked on so far, has gotten larger and heavier than the previous designs. The good news is that these changes appear to be moving in the direction of increasingly realistic, affordable, and buildable boilers, with more easily-designed and reliable control over steam pressure and temperature.

The boiler design mentioned elsewhere on this website, the first in my "steam car crash program" of the past few years, was a once-through type with 8 parallel circuits, a free-flame central burner, and radial outflow of burner gases. This would have weighed about 110 pounds. The "second generation" of boiler designs, starting around 2001, involved several water-level, water-tube type boiler designs, most with many more than 8 circuits, with boiler weights in the 150 pound range, and larger cases, approximately 23" diameter and about the same height. I'll spare you detailed reports on those, suffice it to say that those used flameholder-type vaporizing burners, similar to the burners in Stanley and White steam cars, for even flame distribution under the very heavily-fired tube stacks.

Around the same time, I found George Nutz's article on "Lamont-system" boilers at http://www.stanleysteamers.com/lamont-1.htm, and followed the discussions of this boiler type among steam car students and builders on the internet steam car forums. The Lamont boiler is essentially a coil of metal tubing exposed to a fire, with water circulated through the tubing at 5 times or more the steam generation rate. On its way through the heated tubing, about 1/5 of the water (by weight) turns into steam, and the tube dumps this mix of water and steam into a drum, where the water and steam separate. The steam is drawn off the top of the drum, superheated (heated above its boiling point), and sent to run the steam engine, and the water is drawn off of the bottom of the drum, through a circulating pump, which pushes the water back through the heated tube to generate more steam.

During every pass through the steam-generating tube, about 1/5 of the circulating water is turned into steam and removed from the system, so of course more water is pumped in by the feedwater pump to replace the water removed as steam. On its way to the drum, the cold replacement water goes through some coils of tubing called the "economizer", to pick up the last of the heat in the burner gases, thus preheating the incoming water and increasing the efficiency of the boiler. Overall, the Lamont boiler can be designed to be as efficient as any other type of boiler, about 80% efficient at full blast, and maybe 85-90% when only a little steam is being made (which is most of the time in steam car driving). A boiler could be made 99% or more efficient, but the extra tubing required would make it much heavier & more expensive, and water condensing out of the boiler exhaust would corrode things unless very expensive & often hard-to-work alloys were used.

Now, the Lamont boiler has several advantages, as outlined in George Nutz's article and elsewhere. For one thing, much less tubing can be used, making the boiler lighter, less expensive, and easier to make than conventional steam car boilers of the past. This is because the rapid circulation of water through the steam-generating tube(s) sweeps off steam bubbles as they form. The layer of steam on the insides of the tubes does not conduct heat very well, which limits the amount of heat you can put into water through a given surface area of tubing. But if the steam layer is constantly swept off by fast-moving water, then a lot more steam can be made with the same amount of tubing -- or, the same amount of steam can be made with much less tubing! Also, with fast-moving water inside, more of the tube can be exposed directly to the fire, which puts a lot more heat into it ("radiant heating") than simply running hot gases over the outside of the tube ("convective heating"). Again, this means that you can use less tubing for the same steam output.

Other advantages include no carbon buildup inside of the boiler tube due to overheating traces of oil in the feedwater, and it can use very simple control mechanisms due to the relatively large amount of boiling water inside the boiler -- it reacts more gradually to changes in water content and firing rate, with none of the "overshoot" or "oscillation" caused by control setting changes, which are problems with "once-through" boilers, especially very lightweight ones. These problems are what led me to drop the "once-through" boiler discussed elsewhere on this website, and start work on my "second generation" water-level boilers, which are not documented here.

I did not adopt the Lamont concept right away, however. It has a few disadvantages which I could not see solutions to, so I continued design work on the "second generation" water-level boilers.

One problem was the drum. This has to be a high-pressure steel drum, capable (in my system) of safely holding a pressure of 500 pounds per square inch with a large margin of safety, and big enough to hold at least one or two gallons of boiling water, and consequently heavy and difficult to build. Another problem was the pump. This has to handle the same temperatures and pressures, while pumping hundreds of gallons per hour of boiling water through the tube. It is not easy to find pump drive shaft seals which can handle the pressures & temperatures involved without leaking or generating a lot of friction, and an electric motor to run the pump has to be protected against high temperatures (approaching 500°F) or else built to handle the heat. And the precisely-curved impeller blades of a typical centrifugal circulator pump are extremely difficult to design and machine.

Another problem with the Lamont boiler is the superheater tube, which the steam from the drum runs through to dry it out and improve the performance and efficiency of the steam engine. To obtain good control of final steam temperature, which is needed for good and consistent performance and economy, the usual approach with Lamont boilers is to "hide" or "bury" the superheater tube behind part of the generating tube, so that it receives equal amounts of radiant and convective heat transfer at varying steam-generation rates. The complex and lengthy calculations required to do this are currently beyond my slowly-improving engineering knowledge and skills.

For 2-3 years, these problems pushed me away from designing a Lamont boiler, despite off-and-on attempts at resolving them on the drawing board, so I continued work on my "second generation" water-level boiler designs, with some very interesting & unusual results.

Then, in January 2004, I had one of those weird and exciting "Eureka!" experiences which inventors are prone to have. Within a few hours of brainstorming, I suddenly discovered astonishingly cheap, easy, compact, reliable, and lightweight solutions to the problems of circulating pump design, pump drive, steam/water drum construction, and superheat control! Out of the blue, the Lamont was suddenly fully buildable, with all of its advantages -- and with some new advantages which I had not previously been aware of!

At this point I must apologize for disappointing the reader by not divulging all of these solutions! The details will be revealed soon enough, when the boiler is built and running.

However, in the interest of "infotainment", a few basic parameters and details of my new boiler design can be revealed at present, without compromising possible future patent protection. The generating tube coils will consist of 3 nested vertical-axis helical barrel coils, one inside the next like those Russian nesting dolls. These will pick up both radiant and convective heat by virtue of completely surrounding the cylindrical firebox and being wound with gaps between the turns, through which the hot gases of the fire will travel to an annular exhaust flue surrounding the coils. A flameholder-type multifuel vaporizing burner in the center will provide evenly-distributed heat to generate and superheat the steam; thus, like the "first generation" once-through boiler discussed elsewhere on this website, my new Lamont system boiler will be a "radial outflow" type boiler. The steam/water drum will be relatively small, inexpensive, and lightweight, and will be located outside of the tube-coil case, right next to and probably behind it.

As before, the burner will be provided with a pilot light to keep the boiler hot at all times for instant starting, with no warmup delay. If the car has sat unused for several days, the pilot will turn off automatically, and if the boiler then cools down for 48 hours or more before the next start, there will be a 2-minute wait while the burner and boiler automatically build up full steam pressure at the turn of a key. Details of the automatic shutoff and warmup systems have now been fully worked out.

A new steam temperature/superheat control method has been fully worked out. Sounds mysterious, doesn't it? :)

The "big picture" details are: boiler should weigh 180 lbs total, including drum and burner, measures 27" outer diameter by 18" tall, not counting the drum which is very small, burns 8 gallons per hour of fuel and generates up to 700 pounds per hour of steam at 500 pounds per square inch and 700 degrees Fahrenheit (actually, at full steaming rate, boiler pressure will drop to approximately 400 psi, with still lower pressures in the steam line and cylinders). Total materials cost for this innovative boiler design is approximately US$300, and numerous design features have been optimized to keep the fabrication simple, which would translate into a very inexpensive boiler in production, even in very limited production. For just one example, the helical barrel coils are far easier to wind, and have less flow resistance, than the spiral "pancake" coils usually employed in steam car boilers.

For comparison purposes, a conventional monotube boiler as previously used in steam cars would weigh 300-400 lbs for the same output, and a Stanley boiler of the same continuous output would weigh in at about 500-600 lbs..

Controls will be extremely simple and reliable. A pressure-operated valve, similar to that used in Stanley steam cars, will turn on the fuel supply to burner when steam pressure is below the desired level, and will turn off the fuel/fire when full pressure (500 psi) is achieved. This burner will have a continuously-variable firing rate; the lower the steam pressure, the higher the firing rate, and the higher the steam pressure, the lower the firing rate.

In the feedwater-control department, I do have an interesting tidbit for those who are contemplating or developing their own Lamont-system boilers. I discovered through various studies and calculations that with a constant circulation rate, the water level in a Lamont boiler's steam/water drum will vary according to the steaming rate. When the boiler is making lots of steam, the water level in the drum will be higher; when less steam is being generated, the water level will be lower. I have designed a simple feedwater control device which compensates for this water level variation, and this, along with another new feature of my boiler design, also allows the use of a smaller, lighter, more easily built, safer, and less expensive drum.

As I write this, I am in the middle of working out the crucial circulating pump for the Lamont boiler. The solution in this department is to use a Tesla-type centrifugal disk pump, invented by Nikola Tesla, the very famous and ingenious inventor of alternating-current electricity and many other useful things, some of which are rather controversial to this day. This type of pump is an efficient water-mover, very easily designed and built in a typical home machine shop, and currently in commercial production and widespread use for special applications where a conventional bladed impeller pump will not work, such as pumping liquid concrete. The Tesla pump consists of a stack of round disks with water inlet holes near their centers and a water-outlet volute housing surrounding them. Spacers keep the disks a fraction of an inch apart, and when the disks are spun by a motor or other drive means, the adhesion and viscosity of the water between the disks causes the water to flow down the center of the stack of disks and then outward.

I have obtained an excellent instruction manual for designing and building efficient Tesla pumps, and am working out a Tesla circulator pump design for my Lamont boiler at the present time. Initial calculations leave me with no doubt that a very compact, durable, and easily built Tesla pump will be developed, which will circulate the water in my new Lamont-system boiler at the required pressure and flow rate, with complete success. It is a most fascinating device, and I think I will have lots of fun building, testing, and operating it!

Thus concludes my February 2004 steam car progress report. I would like to add that the engine and most of the rest of my steam car powerplant have changed very little, if at all; the original designs noted on this website continue to survive regular "reality checks" and still look very likely to give excellent results -- promising a reliable, fully-automated modern steam car which will be affordable even in limited production, which will get the same fuel mileage as a comparable gasoline-engined car in city driving (which accounts for the majority of driving for most people), and which will deliver incredibly smooth, silent, easy running, with ultralow emissions and outstanding, effortless, tire-smoking acceleration on demand. It should be a lot of fun to drive!

Peter Brow
Wednesday, February 11th, 2004