LaMont lawn tractor build

Spent the day, and much of the night working on the LaMont lawn tractor....built a frame for the boiler and drum, welded together and bolted it to the chassis. The circulation pump pulley is now belted to the engine....installed a pillow block bearing to support the pump shaft and put in a belt tension adjuster. Everything lines up good, so far. I have the drum and furnace mounted directly above the engine....in the front...keeping the plumbing lengths as short as possible. They actually fit rather well in that spot, and it doesn't obstruct the view (that much). I also have a clear view right down the center of my coils....so any accidental overheating can be spotted. Cleaned out the old gas tank and will use it for a feed water tank....the fuel will be from a 20 lb propane tank mounted in the back. It feels good to be finally at the stage of putting together all the pieces and installing them on the vehicle! I placed the furnace in the spot it's going to be installed, but it is not mounted yet....that will be the next stage.
Here are some pics of the build so far....

Jamison

This is the boiler support frame being built:



Edited 1 time(s). Last edit at 07/30/2017 02:19AM by Arch-Tone.

.....now I have the drum installed:

Here are some closeups of the pump pulley, bearing and pump shaft seal...I haven't added the cooling fin yet, but it will be a 4" stainless steel disk mounted right above the pulley :

I put the furnace in its location...the torch is not mounted yet....I just stuck it in the furnace entrance to get a feel for how it will look. When installed, it will be mounted about an inch away from the entrance. So far....so good...

Jamison

All you need is a GoPro hanging out front, and a little monitor, so you can see where you're going. :-)

Kelly,

Thank you for pointing out this obvious flaw, and I am firing everyone involved in R&D. I have consulted with my design department about this....and how it got past my quality control team is beyond me. They said it qualifies as a "power bulge" and is not much different than an IC vehicle with a blower...or large hood ornament. They also referred me to some other homemade steam vehicles that carry this same flaw....they might look familiar....

Well, Jamison You doing the project so fast, so You possible may have time to consider couple of things. First, You can apply the pump shaft with seal from atop,(change the flanges) so get down the drum. And turn exhoust pipe on the right side(not up). Anyway this location does not give much aditional draft.
Good luck in Your project,
Serge

Serge,

I originally was going to install the shaft/seal at the top....when I was going with the "Turbo LaMont" idea and powering the pump with a turbine running off exhaust steam. This proved to be too complex so I went with an engine driven design, like the water pump in an IC car. The furnace exhaust will eventually be fitted with a longer pipe going straight up...or routed to the side as you suggested. I am also considering (partially) routing the exhaust over the engine head....an idea suggested by Bill Ryan....to help warm it up and keep it warm....as long as the flue gasses can be kept away from the driver (me) and the exhaust temps don't melt the aluminum....might be too tricky considering the time constraints to get this thing running by the September meet.

Jamison

Got this great water level controller for 11 bucks off Amazon....it runs off 12vdc and has a built in 30 amp relay. The instructions state that the "ground" probe cannot be in contact with the pool wall (it's apparently made for swimming pools) but I tested it...with it grounded to my drum...and it works just fine....now I just have to add one more spark plug and my water level control is done. It turns the pump on when it reaches the lower probe....off when it hits the upper one.

Jamison,

What a kind of complexity You faced about turbolamont? I'm stil have this idea in mind as a solution about whole problem of the Lamont boiler simple circulation pump. The more firing, the more circulation the more power for circ. pump. It seems so ideal. No electrics, no sealing problems. In the jet spouting steam|water mixture so much energy that it seems enough to put almost any bladed wheel to utilise enough power for pump. But even not turbo-, why not to put Your pump shaft from the top? Your nice steam tractor only win from this arrangement, will be more neat.

With respect,

Serge

Serge,

The problem with using an exhaust driven turbine is the old "chicken and the egg" causality: You need steam to run the turbine....you need the turbine to make steam. This problem is circumvented by using an engine driven design.....an engine that has an electric starter. The starter essentially "starts" the boiler circulation... to make just enough steam to get the engine moving on its own. I might use that 1/2 hp, toothed belt that Peter recommended....instead of the original engine starter....belted to the pump shaft, just below the other pulley. The original starter is designed for high torque....but low duty cycle. The toothed belt motor I have is rated for continuous duty, and with the pulley ratio of 1:5, it should be able to turn the engine....as well as the pump. I might have to have a valve at the engine intake to open to atmosphere and relieve any upstroke compression, but that's easy enough.

Jamison

Remember that small scale turbines are horribly inefficient. Electric motors and generators are generally <90% efficient and are infinitely controllable. Also remember that steam engine efficiency goes down as the size goes down, which makes it generally better to have one big engine with alternator, and electric motors to drive all the things. Especially since you need to drive feed water pumps, circulation pumps, and blowers before you have any steam.

Here is the new, improved pump seal assembly. I added a stainless steel cooling fin and a grease fitting per Peter Brow's advice. Still have to add another spark plug for the water level control (as Serge suggested) and a blowdown valve at the bottom....



Edited 1 time(s). Last edit at 08/01/2017 08:38PM by Arch-Tone.

Hi Jamison,

Good fast progress, and I like the fin and grease fitting. Ingenious, even if I do say so myself. Main engine running circulation pump is a natural, since it's right there, and the little aux motor, belt, etc is in your shop, so there's the firing-up circulator motor. I just watched your engine video for the first time; fun! Hard to imagine a simpler IC-to-steam conversion. Running under load is the next thing; best of luck.

For engine oil in an engine like this, I'd be tempted to try plain *non-detergent* motor oil, 30w is probably OK for saturated steam at what I'm guesstimating your engine pressure, but there's also 40w, which I think would be good for reasonable superheat. Almost all regular motor oil has detergents, so make sure the label says "non-detergent". I find this stuff in grocery stores, especially discount or small-chain stores, sometimes in drug stores or 99 cent stores, but not in auto parts stores. In SoCal I used to buy Chalet or Coastal non-detergent oil, but after moving to CenTex I now find "Golden State" brand non-detergent oil, 30 & 40 weights, made by Warren Oil Company. Warren Oil has several offices all over the place, east of the Rockies, listed on the back of the quart jugs.

The thing about "ND" motor oil is that it lubes steam engines, handles steam temps without breaking down, is cheap as all get-out, and best of all, separates from water like crazy, instead of forming emulsions with water as happens with detergent motor oil and the stuff you used in the video. So you could take the oil/water mix coming out of your crankcase and drain it from the on-board collection tank into a barrel, buckets, etc, to separate, discard the water in it, and re-use the oil. Might even dry out of the engine between runs, better than that pesky detergent emulsion. Graeme Vagg, who designed, built, and ran many single-acting IC-to-steam conversion engines, once told me in a private e-mail that engine bearing rust was his main concern with single-acting steam engines. Shortly before he passed away, he was still looking for solutions to that. I seem to recall suggesting blowing 220F air through the crankcase for a time before extended shutdowns, but he thought something simpler was possible, perhaps some kind of oil additive.

The only way to get the water out of the emulsion -- 1960s/70s/80s steam experimenters used to call the emulsion "mayo" -- is to boil it. It foams up like crazy during boiling, and suddenly, so use a pot that is like 10x bigger than the amount of mayo you're boiling, and watch it like a hawk. When I made some oil/water mayo and boiled it, as a (dangerous) experiment many years ago, it went back to clear oil, but with tiny white flecks in it -- those were the minerals from the water, and possibly some of the detergent from the oil.

Or, just use non-detergent motor oil, which separates just by sitting. No mayo forms, and no boiling needed.

Your quarter-turn ball valve throttle is the same type used by Peter Barrett in his steam-converted Old-VW engine steam power systems. He built his throttle from scratch; that may not be necessary nowadays, with improved commercially-available ball valve designs. He & Graeme Vagg co-operated in "Project Steam 77", PS77, to turn air-cooled VW gas engines into steam engines, usually with only 2 of the cylinders, and with bash valves and uniflow exhaust. Later Barrett switched to poppet valves and counterflow exhaust, for his aircooled-VW based P92 & P93 engines (1992 & 1993), and said that the poppets lasted much longer than bash valves.

Peter

Zimirken,

Yes small turbines are terribly inefficient (how much in numbers anyway, to be correct), and exactly this lamont drum turbine wiil be even more inefficient because of it's working fluid is a two fase mixture. But still this mixture has a lot of energy. Suppose it has volume ten times more than water at the beginning of the path, so it has 10 times more speed and 100 times more kinetic energy in its flow, so even only one percent efficient turbine is suffice the need, well, say two percents eff. to quit loss in the pump. Otherwise if not used, this energy completely lost. I think it is possible for such turbine to have more than at least 20%(it is only my imaginations, so who really knows?) If to compare this situation with natural circulation, in this artifisial way we again use energy of heating to make circulation. Not bad, for we saving engine horsepower. This turbine device is more relieble than electric motor with seals, it has only two parts to break down - two stainless ball bearings...

Then the "chicken and egg" question, thank You Jamison for pointing it out. Starting problem. We need to have turbolamont starting device. There comes in mind check valve in outlet from the drum to the coil. Before the start we have water in the coil so when lit a fire we may get first steam to start turbine.We may apply jet pump next to the check valve to get sustainable circulation. Electric feedwater pump helps initial circulation through the injector, and for this matter the drum ought to be half empty at start. When circ. pump gets it's RPM, better to switch feed water to the entrance of the circ. pump.

Serge

A while back, in the Bulletin, I submitted an idea for a Lamont pump that I developed based off the idea of a turbocharger. I think it addresses many of the problems of which you discuss. The idea was to have the turbine side driven by feed water rather than steam with the circulation pump being proportionately larger to give the proper circulation ratio.

This gives a few advantages:

1. Water turbines are far less demanding to build than steam, you can basically just run a centrifugal pump backwards if you want. A roller or gear pump can be used as a hydraulic motor, as well.
2. Water turbines readily operate at lower speed....this is important because you can't spin a centrifugal pump very fast before it stops running due to cavitation.
3. The circulation ratio is kept fairly constant, as the feed water flow increases so does the circulation flow.
4. Assuming your starting motor drives the feed water pump, you have circulation right from start up.
5. You can ensure constant operation even when the boiler isn't feeding by using a level control valve AFTER the hydraulic turbine and returning the excess either to the feed water tank or the feed pump suction. This way the hydraulic turbine is always spinning.
6. Any leakage will be from the turbine to the circulation pump side. This means cooler water is flowing past the bearings, which isn't a bad thing. The leakage is unimportant, if kept small, because you want that water to get into the boiler anyhow. The mechanism can potentially be built as a closed unit with no shaft seals other than labyrinth.

Regards,

Ken



Edited 2 time(s). Last edit at 08/02/2017 07:34AM by frustrated.

That's a brilliant idea, Ken!....I am going to use a 2400 psi pressure washer pump for my feed water. I'm sure you are aware, it's designed to run off a gas motor and has a bypass built in that internally cycles the flow to allow the engine to idle....at least until it reaches a certain temperature and a thermal relief dumps it. My pump has a non-resettable thermal fuse that has to be replaced if activated. I was going to attach the pump directly to the engine shaft and use an actuated bypass valve to redirect the flow back to the feed water tank....I figured it would keep the water from getting too hot and avoid blowing the thermal fuse. Applying your idea would regain some of that otherwise lost energy and put it back into the system. My understanding is that water turbines (i.e. Pelton wheel) are very efficient and, like you said, be a better RPM match for the centrifugal pump compared to a steam turbine.
I originally had in mind using a small impulse turbine along the lines of the Doble condenser fan type....but fans and pumps are two different animals. Your idea is superior.... however....it's a little late for me to make such a change....if I'm going to have a working vehicle by the meet.
I am thinking of powering the pump with an electric motor now....so I can have better control of it and not have it directly drag on the engine. I have one that will do 2,600 RPMs and I believe is 1/3 hp but I'm not sure if it will work....if anyone has any experience with running a gas motor type pressure washer pump off a dc electric motor, any advice would be appreciated....then again....I can always just "try it and see".

Jamison

I like the water turbine idea that Ken proposed, too. Once I thought this way but dropped because of the moments when there no need for feed water in the boiler. Using bypass valve through the turbine is a very nice idea. Bulletin is to be studied, seems there coming time to join SACA, only need to collect some money...
There is not too bad that good idea came a little late, Jamison, so we all have a chance to know about practical workability of Your copper tube high temperature seal! There is no bad without good. The idea worth to be checked out, either, and after meet Ken's idea can be tried.

Serge

Got this teflon O ring that is the same o.d. as the bore of my cylinder....I plan on putting it in place of the oil control ring on the piston. The original oil control ring/spring broke and wanted to try this instead. My main concern is the engine temps at that area will be too high....it will run off superheated steam. I fabricated a brass piston ring out of 1/8" round stock that reduced blow by significantly, but the friction was too high and made the engine hard to turn. I figure a teflon ring....if it doesn't melt....would be ideal. I could put a few wraps of feed water tubing around the bottom of the cylinder....to help keep the temps under control....but I'm concerned that may cause more problems than it solves. Anyone have any thoughts on this idea?

Jamison



Edited 1 time(s). Last edit at 08/04/2017 09:41AM by Arch-Tone.

There is a design criteria for using Teflon as a sealing ring. Teflon expanses considerably, PTFE on the other hand is a bit slower. In most cases you will see 500F as the max temperature but PTFE in a non oxygen atmosphere is good for 2500 F
Rolly

Rolly,

Here are the specs for the ring I have....it calls it both Teflon and PTFE in the description. I always thought "Teflon" was a brand name and "PTFE" was a generic name for the same substance. Can you tell by the specs which one it is? 2500 F is amazing....would a piston ring, covered with a film of oil and/or oxygen displacing steam, qualify as a "non oxygen atmosphere"? I have it installed already (but haven't run steam through it yet)....and the compression is outstanding. If it fails (melts) at superheated steam temps, will it be catastrophic or just break down and settle at the bottom of the crank case? My hope is that the higher temps won't reach the bottom of the piston where the ring is installed. Sorry for all the questions and my ignorance on the subject.

Jamison

Too long absent here--but I just HAVE to reply to this one!

My experience with the RJ Smith conversion of a Merc outboard engine showed that the AVERAGE temp of the steam in the cylinder was substantially lower than the inlet temp--and BTW the inlet temp in your app is likely to be quite a bit lower than the boiler output due to cooling along the way to delivery (unless you have some pretty fabulous insulation in place!) The advantage here is due to the greater expansion ratio of the uniflow type. I also suspect that the average temp at the piston crown may be even lower (discussion on this plz). Bottom line is, I used a measured temp of 600-650 degrees F. coming out of the boiler--but the all-aluminum engine never suffered any detrimental effects.

Just a FWIW and I hope to stimulate some discussion on this issue.

Back into obscurity, Bill

Bill,

The plumbing from the superheater to the engine will be within the flue of the furnace the whole way, with part of the exhaust blowing over the head. This is to minimize thermal losses....an idea I got from Bill Ryan at the spring meet. I know I have to be careful to not let it get too hot on the head or it could melt the aluminum.....so the amount of flue gasses blowing there will be small. I might put a few wraps of feed water tubing around the cylinder base, by the uniflow exhaust ports, to lower the temps there. This is in line with Professor Stumpf’s principal of "keeping the hot end hot and the cool end cool". I will measure the temps at different points once I get everything hooked up and running....might even be by this evening!....wow....I could actually be driving this thing tonight....without feedwater pump installed, though. Will just fill up the steam separator drum to the water level and run it it that way, until it runs out, just to test everything. Will post video if I do.

Jamison

Looks like I might have a working steam powered vehicle by the fall meet!! Rolled the tractor outside, tested steam generator and engine, using a 120vac pressure washer for a feed pump. The LaMont steam generator worked like a champ, making ample steam with furnace at full blast....decided to power the circulation pump with a dedicated electric motor and not off the engine, which works well and simplifies things. The pump seal held up and the motor had no problem turning it rapidly. My engine was not running properly, though....I decided to play with the valve timing / cam shaft position when I installed the Teflon (or is it PTFE?) piston ring and I need to put it back where I had it. I didn't want to put a load on and try to drive it just yet...I would rather wait until it has full controls and feed water system installed, not to mention the motor set up properly. I took video of it regardless and posted it on my YouTube channel. Here is the link:


[youtu.be]

Let me know what you guys think....your input has been invaluable so far...and a big help to a steam novice such as myself. Attached are some still photos from yesterday's testing. Don't worry....the self tapping screws holding the bearing and motor to the frame will be replaced with proper bolts....I used them as a convenient way to hold everything in place for the purposes of testing and making sure everything lines up correctly.

Jamison

Jamison
It all depends on the percentage of carbon fill. The O rings are designed for radial shaft sealing not as a piston ring. For a piston ring it would be square cut and in the slot there should be space behind it for expansion. Teflon expanse considerably. The face of the seal will wear cupped or con caved.
Rolly

Jamison
What I posted is not what my mind was thinking. PTFE is Teflon I used carbon impregnated PTFE. For bearings and seals.
You can get PTFE impregnated with all kinds of stuff for different applications.
Carbon, Graphite, Glass, Bronze, Aluminum, and many other substance.
Carbon impregnated PTFE seals can be good for 2500F in an oxygen free environment.
Rolly

Rolly,

Thanks for the clarification. I've heard of impregnated PTFE materials....and when looking for sources of raw PTFE, I was told by a supplier that PEEK was ideal for what I was looking for. I believe it has carbon in it, if I remember right, but the price was too high at the time. I did enlarge the piston slot, where the old oil control ring was, so it should have enough room for expansion. The video I posted of the LaMont Lawn Tractor running has the teflon ring in place, I ran it for about an hour on superheated, and despite my cam shaft position being off, it ran ok and has not lost any compression. Next time I pull the piston out to inspect....I will post pictures of it and the ring.
Rolly....I've seen your work posted on this site and it is outstanding. That is one stout little circulation pump you made!....I envy your machining skills and expertise. I am at the stage where I am making a bourdon tube pressure sensor....to set the peak pressure of my steam generator. I am concerned about my drum end caps....being the weak link in the chain....and wanted your (or anyone's) advice about it's pressure capability. My drum is a schedule 40 4" pipe and the end caps are 1/2" plain steel plates with (8) 3/8" stainless steel socket cap bolts holding it to the flange. My hope is that it can handle 1000 PSI, with a safety margin. It c.w.p.t at 1600 PSI....but I want to be sure. Attached is a close up of the top end cap.

Thanks,
Jamison

Quote: "concerned about my drum end caps....being the weak link in the chain....and wanted your (or anyone's) advice about it's pressure capability. My drum is a schedule 40 4" pipe and the end caps are 1/2" plain steel plates with (8) 3/8" stainless steel socket cap bolts holding it to the flange"

4" ID pipe?

Calculate the area of the circle, and that is: pi X r2, or 3.1416 X 2 X 2 = 12.56 square inches. At 1000 psi that is 12,560 pounds of force or at 1600 psi 20,000 pounds of force or ten tons. Google the spec on the bolt and multiply the number of bolts by the shear strength, then use about 40% safety margin.

At 1600 psi on a 4" schedule 40 pipe, that is over the working pressure of 1400 psi, with a burst strength of 5500 psi(I looked it up).

Anything, especially boiler components that are going to contain pressure where a failure could result in some sort of damage or injury, should be hydrotested to 1.5 times the intended maximum pressure. A failure at that pressure is more than likely going to be catastrophic rather than a simple leak.

I hydrotest everything. I treat boilers like guns, they are all loaded, and no boiler or air tank, or pressurized fuel tank that I will be using/operating is safe until I test it.

Be careful.

-Ron

Another thing I thought about after this was posted was fastener type in this application. There is probably a spec on the type of bolts that should be used. It seems to me that hardened bolts would not be the best. Socket cap screws in steel are typically Grade 8, from experience, I've seen them break without much stretching. Seems a softer bolt and an adequate number of them for the load would be safer. I'm just guessing.



Edited 3 time(s). Last edit at 08/08/2017 11:52AM by IronChief.

Rolly,

I found this chart on the internet when searching for "pipe pressure ratings".... it shows the 4" schedule 40 pipe as having a working pressure of 1400 and a burst pressure of 6,300 psi....it looks like a reprint of an older chart, so not sure if it's still relevant. Also....does the fact that it is an unfired vessel make any difference? I can hydro up to 2600 psi now with my new pump....will definitely do so before I up the pressure, along with calculating what my bolts can handle (thanks for the info). I have been running it at around 500 psi with my relief valve set at 550.

Jamison

Jamison
There is a formula for calculation of what is referred to as end plate deflection. What it all boils down to is after the plate is under pressure and bowed it will come back to O flatness with no pressure. In other words you’re not exceeding its stress level.
However my past experience says ½ plate on a 4” diameter pipe is fine. My ASME Code boiler I designed the drum is 8” with a ¾ unstayed end plate. The plate should be SA516 grade 70 plate. To be code, A106 pipe is code.
The bolts are a concern SS bolts expand more than Grade 8 steel bolts. All high pressure steam rated valves use Grade 8 steel bolts even with SS body valves. The welded joint should be PW16 or PW16/a
Rolly



Edited 1 time(s). Last edit at 08/08/2017 01:39PM by Rolly.

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