The Steamboating Forum

I been digging around in the basement reading every post ever posted and am finding answers to questions I had not even thought to ask yet.

One design boiler design I'm quite fascinated with is the LaMont; this is a forced circulation boiler. This design provides even higher specific outputs than a monotube, with NONE of the control issues... but it does require a reliable boiler circulation pump,
and power (steam or electric when starting) to drive it. There are extensive discussions ongoing on the SACA (steam car) forums
http://steamautomobile.com/phorum5214/list.php?1, where I've been known to lurk.

- Bart

I ran across this post from you and found that we share the same interest in the La Mont style boilers. Have you found a source for a pump that would work for a La Mont that would operate under the temperatures and pressure we use?

I know they are made I just have not found anywhere I can get hold of one yet. Since I am still in the "finish my shop" mode I am considering building a boiler that I can experiment with while using it to heat the shop. The highest pressure pump I have found is 200 but it was designed for hot water not steam duty.

Cheers,
Scott

Cyruscosmo wrote:I been digging around in the basement reading every post ever posted and am finding answers to questions I had not even thought to ask yet.

One design boiler design I'm quite fascinated with is the LaMont; this is a forced circulation boiler. This design provides even higher specific outputs than a monotube, with NONE of the control issues... but it does require a reliable boiler circulation pump,
and power (steam or electric when starting) to drive it. There are extensive discussions ongoing on the SACA (steam car) forums
http://steamautomobile.com/phorum5214/list.php?1, where I've been known to lurk.

- Bart

I ran across this post from you and found that we share the same interest in the La Mont style boilers. Have you found a source for a pump that would work for a La Mont that would operate under the temperatures and pressure we use?

I know they are made I just have not found anywhere I can get hold of one yet. Since I am still in the "finish my shop" mode I am considering building a boiler that I can experiment with while using it to heat the shop. The highest pressure pump I have found is 200 but it was designed for hot water not steam duty.

Cheers,
Scott

Hi Scott -

I've found a few pumps that would work for a small Lamont but they're likely to be quite expensive as they're industrial units. For industrial service, a 1.5 hp pump is tiny... and we're looking for something a tenth of that. The steam car folks have experimented with Lamont boilers, but in that case the design center is very high output with light weight; the edgy designs they use have little place, I think, in a steam boat unless it's for racing purposes. My goal is a reliable, quiet power plant; I'm sure one could build a Lamont to do this but there's quite a bit of engineering (and trial and error) to do to make something really right. I think a B & W or better yet one of the modifications of that design that offer a more compact structure is a better choice for what I'm looking for in a steamboat. My next boat is planned to be fairly good size (34' feet or so) with a cabin and used in the Pacific Northwest; we don't need to shave every pound for a boat that size. I'm also not interested in high pressure (for me, above 250 or so psi); the difficulty in finding valves, insulation and other components make such designs quite expensive to build, and the gain in efficiency modest; as a result of all a simple welded steel boiler seems rather a sure thing.

Some design comments on the Lamont... you'll need to insure turbulent flow (say Reynold numbers above 10000 or so) to realize the advantages of the pumped circulation. This means about 2 gpm in 1/2" pipe - not a lot, but it needs to happen so long as you have fire. I'd not consider solid fuel suitable for a Lamont boiler w/o redundant pumps & reliable pump power; I'd also consider multiple pumps required (or some other form of aux. power) if in open/dangerous (tides/currents/surf) waters. Remember that the pump only needs to produce a few psi pressure head - but the seals need to take full boiler temperature and pressure, which is what makes finding such pumps difficult. Also, the water you're trying to pump is about to flash into steam, so the design of the pump needs to require a very low NPSH.
From Wikipedia: "Careful design is required to pump high temperature liquids with a centrifugal pump when the liquid is near its boiling point." You can use a positive displacement pump, but gear pumps are probably out since any scale or such in the boiler water would soon trash the pump. A 2" bore, 1" stroke double acting opposed piston pump with lift checks and Viton or Teflon packing running about 100 rpm would do the trick - but it has to run all the time, even when the fire is just lit, so you'll need to use an electric motor.

If I were trying to build a Lamont boiler, I'd focus on the pump... build what appears to be a suitable pump, and test it by pump water in and out the mud drum of a regular boiler being fired, measuring the delivered pressure across a partially closed valve. When you get one that will live in that service, you can start w/ the rest of the project.

- Bart

Hey Bart

When you do get to the point you are building the new boat and if that build is taking place up here I would be very interested in lending a hand. I live about 20 miles north east of Seattle and a trip to Lopez island is just a ferry boat ride away.

After my shop is finished here in a couple months I will be setting up the foundry and kiln for making the castings I will need for my own 30 foot S.L. project. I am hunting for a nice Bridgeport mill and tooling, I already have a lathe and tooling ready to go.

Anyway, from all the previous posts I have read I will be staying down below the 250 psi mark as well. Electric motors are fine as I had planned on running an alternator of some sort to keep a set of batteries charged for navigation, cabin lights and such. But once up to steam it is possible to use a steam engine to keep the pump moving.

Some specs:
So I need to move the water through the tubes at a rate of at least 2GPM. The system will have a max working pressure of no more than 250psi, but will most likely run at 150 to 175.
The steam table shows a temp of 406.11 for 250 psi steam is that a good starting point for max temperature as well?

So as far as the pump goes ya think a 2 inch bore x 1 inch stroke will do the job for one 1/2 inch tube? That gives me an idea!

If looking at an impeller I would need a very low NPSH. So installing the actual impeller inside the drum where the suction would be in line with the water circulation imparted by the return would probably be the way to go.

I think I like the piston pump idea better. As long as it cycles a bit slowly the water from the boiler drum would pretty much force it's way into the intake.

Cheers,
Scott

Cyruscosmo wrote:Hey Bart

When you do get to the point you are building the new boat and if that build is taking place up here I would be very interested in lending a hand. I live about 20 miles north east of Seattle and a trip to Lopez island is just a ferry boat ride away.

After my shop is finished here in a couple months I will be setting up the foundry and kiln for making the castings I will need for my own 30 foot S.L. project. I am hunting for a nice Bridgeport mill and tooling, I already have a lathe and tooling ready to go.

Anyway, from all the previous posts I have read I will be staying down below the 250 psi mark as well. Electric motors are fine as I had planned on running an alternator of some sort to keep a set of batteries charged for navigation, cabin lights and such. But once up to steam it is possible to use a steam engine to keep the pump moving.

Some specs:
So I need to move the water through the tubes at a rate of at least 2GPM. The system will have a max working pressure of no more than 250psi, but will most likely run at 150 to 175.
The steam table shows a temp of 406.11 for 250 psi steam is that a good starting point for max temperature as well?

So as far as the pump goes ya think a 2 inch bore x 1 inch stroke will do the job for one 1/2 inch tube? That gives me an idea!

If looking at an impeller I would need a very low NPSH. So installing the actual impeller inside the drum where the suction would be in line with the water circulation imparted by the return would probably be the way to go.

I think I like the piston pump idea better. As long as it cycles a bit slowly the water from the boiler drum would pretty much force it's way into the intake.

Cheers,
Scott

Well, when we get to boat building I'll let you know ... I need to get my big engine built first.

Some handy calculators for sizing stuff:

http://www.spiraxsarco.com/resources/resources.asp
http://www.engineeringtoolbox.com/reyno ... d_237.html

Some notes on pump sizing... the circulation pump capacity needs to be at least 5 x the steam requirements of the boiler. This keeps the quality of the steam/water mix at about 20%, assuming that steam formation is all done in the coil. If you punch the numbers on the specific volume of 20% quality steam at 250F, you'll see that volume has jumped enormously - density has dropped from 53 lbs/ft^3 to 2.74 lbs/ft^3 - so your velocity has gone up nearly 20x. If the discharge from the coil enters the drum off-center, this will impart a significant rotation to the water in the drum, which you can use to pressurize the pump inlet. In fact, there have been forced circulation boilers that used a turbine and pump enclosed in the steam drum in exactly this way - a sort of turbocharged boiler coil, with bearings running in boiler water.

So, if you're building an engine that needs say 200 lbs/hour steam, you'll want 5x that amount of water in circulation - 1000 lbs/hr, or 1000/8/60 = 2.1 gpm.
For a 1/2" schedule 40 pipe, that works out to be 2.1 ft/sec for a Reynolds number of about 10k - nice and turbulent. Remember the coil exit velocity will be 20x this.

- Bart

I've been following these posts about high output boilers. I find it all very technically interesting but I cannot imagine sharing boat space with anything like that.

Electric motors. Centrifugal pumps. Noisy burners. Have you all lost your minds? Obviously there is a wider variation of what steamboating is all about than I had imagined.

I value silence greatly. I resent time spent tending systems. I love it that my stupid 'donkey boiler' has a lag time measured in minutes when the load changes or something acts up. There are sometimes embarrassing delays when it's time to leave the dock while things get a little more energetic in the firebox. Sometimes I pop the safety when I come to the dock.

Yes, the wood is inconvenient to store. Sometimes interesting creatures come out of the pile. But I can fool around all day and still not have any smelly oil on my hands. And except for some bark, the stack smells aren't bad.

I hope your efforts come to fruition. Better you than I.

Yours in friendly amusement,
Mike

Mike, probably for quiet, and lack of thought intrusion, you won't beat electric power, but somehow that seems to lack excitement.

Depends on where you stick your fingers! Some of my more profound and startling experiences have been as result of electrons playing about in my body.

Mike

As a parting thought, I have a sign on the wall in my shop that often causes visitors to look thoughtful. It says, "He was a good man but he didn't know about flywheels."

In terms of noise, esp. in a enclosed boat, I have to agree with Mike... I don't want to listen to fans, pumps and blowers and other things running at more than a few hundred RPM.

The virtues of a Lamont boiler are that is can be made fast steaming and can be a compact design since much higher btu/sq ft transfer rates are possible than with natural circulation. However, neither of these are particularly compelling in a 34' cruising steam boat, other than perhaps trying to maximize interior space - but a VFT might do as well as anything else in that regard, since those are tall rather than wide. There is something to be said for being able to steam a mile or two after the fire goes out...

I think I'll stick to a design that doesn't require electronics, complex control systems or is absolutely dependent on a circulation pump.

- Bart

So while you are feeling all inventive, here's a problem that has been pestering me for years.

I would like to be able to force the draft on my VFT. Not all the time or heavily but enough so that if I need 20% more for an hour or so, I have it available.

Also, I am setting aside a regular steam blower for now as I don't care to start carrying a bunch more makeup water. I use enough now messing around with the whistle for good looking women!

What I'd really like is a way to put a fan in the stack or a fan outside the stack and duct it up there to work as an induced draft blower.

Now Wes's dad's boat has that automotive supercharger setup. That has possibilities and whenever I'm in a wrecking yard I keep an eye out for one. He says that it is noisy though.

But that only works when the main engine is running. Sometimes I'd really like to get up steam faster than my natural draft does it. Maybe a steam blower would do for that. I have that air amplifier that you egged me on to buy. Maybe just duct that in. It's made of aluminum so it would probably take the heat but I suspect it would interfere with natural draft when not in use. And, again, it would use more makeup water.

I keep thinking that it should be possible to drive a fan in the bottom of the stack with a small single cylinder engine. The engine to be down near the main engine and perhaps a slender toothed belt for the run up to the fan. How in the heck can I drive a fan that is inside the stack? It's a difficult environment. Gears would have a short life. Flex shaft? Multiple U joints?

I wish I could come up with a scheme to drive a fan from the main engine when needed for longer runs. Then I could waste a bit a water on start up with a simple blower.

I think that this has all been beat to death over a hundred years ago.

Mike

You can put the air amplifier outside the stack, and duct the output up the stack w/ a sweep bend.
You can fit a taller stack and double wall it to keep the air hotter - use natural draft as much as possible.

If you run w/ the firebox door shut, why not add a fan that pressurizes the ash pan? that's closer to the engine, right?
A squirrel cage fan might work... Drive it w/ a long round drive belt like they used for dentist drills.
https://en.wikipedia.org/wiki/Centrifugal_fan

If you need to exercise your arm, fit a blacksmith's blower . Or take a blower like that and drive it off the engine shaft....

- Bart