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aubrey
12-05-2006, 09:58 AM
Hi Everyone
Problem: Need mechanical energy source in Malawi but petrol/diesel VERY expensive and electricity not available.
Looked at steam - Too Dangerous for the local level of expertise.
Looked at Stirling and Atmospherics as well - not enough grunt.
Came up with the following design which will give me power (how much I dont know) WITHOUT needing a boiler.
The fuel will be wood.

Theory on how it works:
Normal crank, conrod, piston and cylender.
The crank has a cam (as opposed to an eccentric) to operate the port sealer/water injector via a conrod.
The port sealer has a spigot on the front which engages the water injector piston (after the port is closed).
The water injector piston moves forward, closes the hole to the water supply hopper, builds up pressure which forces the water thru the one-way valve into the hotbox steam generator.
The hotbox steam generator has the fire made around it and is hopefully just about red hot at all times.
The injected water turns to steam which pushes the piston/conrod down which turns the crank.
At bdc the cam retracts the port sealer (the water injector piston moves back opening the port to the water supply and is re-filled) and the piston moves up, exhausting the steam.
Just before tdc the cam moves the water injector piston forward completing the cycle.

The beauty is that there is no boiler to blow up! This is VERY important as the people who will operate the machine are at best semi-literate and even if the thing overheats or runs dry, I cant see an explosion happening.

Connecting 2 together 180 degrees out of phase would give a constant power stage at the flywheel.

Please remember that this is not a desktop model but will be used to power irregation pumps, sawmills and the like in a very poor and rural setting using wood as the fuel source. Currently they are irregating thier crops by bucket from a well point at least half a mile away. They simply dont have enough manpower to get enough water to the crop and the result is a food shortage.

What I would like is for the members of this forum to rip the design apart and tell me what is right with the design, what is wrong with the design and how to rectify the problems.

Also, advice on what material to use would be appreciated. (ie could I use a VW Bug cyllender barrel and piston). Please bear in mind that average annual income of these people is less than $100 a year and the more "scrap" I can use, the better.

Thanks a lot guys, look forward to hearing from you.
Best Wishes,
Aubrey

aubrey
12-06-2006, 08:32 AM
Before going any further, I need a proof of concept.
Went into the local lawnmower repair shop and got an old 4 stroke Briggs & Stratton lawnmower motor (donated).
Now all I need is a piece of 2 to 3 inch pipe to use as the steam generation vessel.
I have an old VW Bug brake master cyllender I can use as the water injector.
The steam generator can be screwed into the spark plug hole.
I'll have to make up some sort of cam on the putput shaft to operate the water injector.
Another cam can open both existing inlet and exhaust valves so that they operate as the exhaust port.
May need a heavier fly wheel (the alluminium one wont be worth much)
Bodge up a frame to mount everything on, suspend it over the barbeque and see what happens.
I see a busy week-end ahead!
Aubrey

PS. Just got off the phone to a pal with an aluminium foundry who has a contact with a cast iron foundry about 3 miles from where I live (didnt even know it existed!). The cast iron guy says casting will not be a problem.
Looks like I may have a nice Christmas present for Nyrenere (my Malawian friend)

handlewanker
12-06-2006, 09:34 AM
Hi Aubrey, if you are concerned about safety, then go back to basics and I mean 1700.
The steam engines then were atmospheric engines and the steam pressure was about 2 psi, which was not enough to blow your hat off.
These engines worked on the principle of flooding a large diam cylinder with low pressure steam and then condensing the steam to cause a vacuum to pull the piston up the cylinder.
This is very basic engineering and the piston seal was usually a leather skirt that was immersed in water to stop the air getting into the cylinder.
The boiler was often made of lead as it only had to bring water to the boil and pressure was not required.
The beauty of the set up was that it could be fired by any fuel that would burn, even solar power.
If you are unfamiliar with the principle just look up Newcommen or James Watt on the 'Net.
These engines do not require a crankshaft or flywheel to operate when pumping water, and could be operated by the village idiot if required.
The beam engine is a typical design type.
Ian.

CJL5585
12-06-2006, 09:40 AM
Aubrey,
I am somewhat illiterate on steam engines, but I wish you the best in your quest for a power source.

Good Luck.

handlewanker
12-07-2006, 11:23 AM
By the way Aubrey, once this "engine " has been made and installed, will you be around to keep it going?
If not, how the hell will a bunch of ignorant people be expected to even understand the goings on in a mechanical device that is working at the limit of it's capacity when it breaks down?
The very fact that water injection is contemplated is the first source of breakdown.
The simplest device is the most complicated to design and make.
SOMEONE has got to be trained to be able to take it apart and reassemble it without too many bits left over.
I see you mentioned a foundry just down the road.
Are you contemplating re-inventing the wheel?
If the sole purpose is to bring water from a distance then a simple viaduct filled with a water wheel or wind mill driven archimedean screw will be cutting edge technology in this instance.
There must be a river or stream nearby which can be dammed to supply water power?
I don't suppose the whole tribe could be re-located to the water source thereby killing all the birds with one stone.
What fuel are you going to use to power it?
If it's wood, how are they going to cut enough wood without deforesting the immediate area and so adding to the further advance of the deserts as has happened in other areas.
I would strongly advise mounting the engine on a mobile trolley, like a traction engine, so that as the wood is depleted in the immediate area the engine can be powered up and so go foraging for it's own supplies on an ever increasing circle.
I hope you don't think I'm unjustly picking holes in your project. If you can overcome any criticism in this endeavour then it will win.
Ian.

aubrey
12-08-2006, 12:41 PM
Hi Ian
They are going to have to do it themselves after a little bit of training.
These people are definitely not "ignorant". They survive in an environment that would kill most of us in a matter of weeks.
They simply do not have the exposure to technology that you or I do and therefore do not understand how dangerous leaving a pressure vessle unattended could be.
Therefore, dont give them one.
They simply march to the beat of a different drum (possibly you have heard the expression "African Time"? I'm sure that rural south Americans have a similar concept.).
As to the "water injection", my trial unit will use a VW Bug brake master cylender (simply because I have one lying around). Production model will probably have a leather sealing washer simply because they will be able to make a replacement locally when they need one.
Some of these guys are very intelligent and ingenious in thier own way. In one of the towns I saw an arc welder that had been made using 4mm fence wire wound with insulation tape to make the transformer coils. And best of all is that it worked.

The area is very sandy and although there is enough water, it is at least 3 to 4 meters (10 - 12 ft) down. We have to get it UP! Making a dam doesnt work because the water soaks away faster than it is flowing in.
There are no rivers or streams as such because any surface water simply seeps away and the wind is not very strong - when it blows.

As to fuel, these people have been carrying out good conservation practices since they settled the land which was before europeans colonised Africa and the Americas.
Normally, the area around the village is devided into 4 sections (north, south etc) and each year, only 1 area is used. Also, some trees are marked and are not allowed to be harvested so that they can grow into "big wood" for use in the building of housing. So every section is allowed to re-generate for 3 years and harvested for 1 year. And if you have to walk 4 miles to get wood then that is what you do.
The whole thing is controled by the headman who simply kicks you out if you dont live by the rules. Therefore you live by the rules, no questions.
The only time you get de-forestation is when someone from outside comes in and strips the natural resources and sends them out of the country. Nigeria and Congo are good examples of this and guess whose dollars and euros and rands buys the timber. Sometimes I have to wonder as to who is more civilised - them or us.
At the present time, the children do the water carrying and when it is hot, ALL the children are roped in because if the crop fails, the village starves - simple fact!.
This means no school and that is what pi$$es me off but I can see the point that food comes first and all else is second.
So the bottom line is that it must be simple enough to repair in the field, cheap enough to be sponsored and safe enough to be used by the local population.

As to "unjust criticism", bring it on!!!
Maybe you will uncover something important or vital that I havnt thought of and maybe you can get a better insight into how other people live.
And hopefully it is a win win thing.

Anyway, thanks a bunch for the interest and comments.
Best
aubrey

handlewanker
12-08-2006, 01:44 PM
Hi Aub, I lived in South Africa for ten years and South West Africa in the Namib for another ten years, so I know where you're coming from.
Probably the term "ignorant" was a bit strong, but it meant a lack of technical understanding beyond 19th century technology.
As far as pressure vessels are concerned the method of atmosperics is to use low pressure steam, 2 psi, to evacuate air and condense it to create a vacuum. This is extremely low tech and even a child can manage it.
This method was used to pump out deep mines in the early years before high pressure boilers came into vogue, but I expect you are familiar with the history of steam in the Industrial revolution.
From your description it would appear that the people are pretty well organised.
I wouldn't go a bundle on lashing up a Heath Robinson device just to see the wheels go round.
Just looking at the design indicates that with the proper proportions for piston area, fire-box capacity, and injection quantity will make it work, as this method is the heart of a monotube boiler and engine.
Even if you get the VW set up to work it will not be reliable and you will have to go back to the drawing board to design something that is practical and is able to be made for next to nothing, otherwise you will be labeled as the "white man's revenge".
The VW is labeled as "Hitler's revenge".
Ian.

aubrey
12-10-2006, 12:48 AM
Hi Ian,
Sorry about the "soap box" trip - Definitely an over-reaction on my part - appologies!!!
Back to business.
I'm not too knowledgable about the various technical designs of the steam engine and that is why I am asking for help.
The atmospheric design needs to be rather big from what I can see and the point you brought up about being mobile is actually very relevant in this case.
Its going to have to be small enough so that 2 people could lift it onto an ox cart to transport around.
As to the VW parts, merely looking for a source of components (they can be bought 2nd hand at scrap metal prices).
As to the "Hitler/White Mans Revenge" part, there is a device called a treadle pump which was introduced up there. Consists of 2 pistons, 2 pedals and a couple of non-return valves. Works very much like one of these stair climbing fitness machines. The problems: the one way valving is "delicate" and wears out quickly and as the seats are part of the body casting, once they are worn, throw the whole unit away. The pistons are pvc but the cylenders are stainless steel - expensive! I think that whoever designed them made a lot of built in redundency to create an on going market for them.
Anyway, its now 7:45am local and I'm heading for the workshop.
Best and Thanks
Aubrey

epineh
12-10-2006, 05:58 AM
Is there a total lack of wind there? The windmills I have seen use a very large diameter blades, with a simple crank arrangement, and a simple up/down piston pump, they work surprisingly well even with light winds, very simple to make and maintain. Just a thought.

Russell.

thkoutsidthebox
12-10-2006, 10:10 AM
Hi aubrey,
Best of luck with this project, its very interesting.

Im just wondering how your calculating the piston diameter in relation to the size of your steam chest, and the size of the steam storage, and generation rate, in relation to the expected piston movements (rpm) ?

I dont know anything about engineering one of these but in your pic above the piston looks very large compared to the steam box. I'd think that maybe the steam box should be larger....

You said:


The area is very sandy and although there is enough water, it is at least 3 to 4 meters (10 - 12 ft) down. We have to get it UP! Making a dam doesnt work because the water soaks away faster than it is flowing in.
There are no rivers or streams as such because any surface water simply seeps away and the wind is not very strong - when it blows.

As I mentioned above, I dont know about engineering one of these, so please excuse my lack of knowledge. Will there be enough water being pumped to both supply the unit, and supply sufficient water to irrigate the required area?

Will you have to build an aqueduct system aswell to prevent the pumped water soaking "away faster than it is flowing in" before reaching the irrigation area?

Last question :).....what size area are you hoping that one of these could be used to irrigate (Pump rate liters/min)?

handlewanker
12-11-2006, 09:39 AM
Hi Aubrey, No problem with the "retoric from the pulpit" just makes good reading, but "hoisted up on an ox cart by two people'? I don't think this would be a good idea.
First off it would severely limit the weight and size that you can make it to.
Secondly it would have to be fired up and cooled down which would make it awkward to use.
Personally I would make it as a fixed in position with the infrastructure around it to keep it happy, also someone will "adopt" it and keep it lovingly tended to make it reliable.
Some people just get "broody" that way with machinery.
If it simply had to be moved I would make it so as to be towed behind the ox cart with it's fuel store and paraphanalia to make it self contained.
Looking back on the designs of the model railway engine builders, the injection pump should take the form of a displacement plunger pump where the piston doesn't actually touch the cylinder bore but displaces the water by it's intrusion into the pumping space.
This will prevent lack of lubrication on the pump piston from failing it prematurely, or causing the "boiler" to coke up due to oil being burnt there.
These pumps are usually driven by the axle of the loco and have to pump against boiler pressures of about 80 - 100 psi.
They are a bronze casting with a stainless steel ram and have a long wear life, very reliable. Gland sealing is effected by either Viton "o" rings (high tech, not recommended due to hard to get etc) or just greased braided yarn,cotton fibre etc.
The design is very simple and can be cast in the backyard type foundry and machined in very primitive simple machinery, even a drill press.
I would recommend that the firebox be made from cast iron so that it can be fired up and hold the heat while the water is just injected at a controlled rate to give the flash steam volume.
If the firebox/boiler is cast as one piece, it can be made to a simple pattern, by the dozen, with minimum machining, to enable it to be bolted on and off for simple replacement when it scales up or corrodes out.
The piston cylinder bit may be tricky, due to lubrication requirements.
Here I would use a large two-stroke engine (vespa scooter 150CC ?) with the transfer ports blanked off so that piston lube can be added to the steam supply and totally exhausted to prevent boiler contamination, and crankshaft lube contained in the sump off side.
Using a car type engine has too much mass and lubrication of the bores and big ends and main bearings would be a serious problem, where hot steam and water in quantity were present.
In this endeavour I would strongly advise contacting someone in the live steam model railway fraternity, and pose the scenario that you intend to pursue.
Ian.

balsaman
12-17-2006, 05:47 PM
Leonardo DaVinci was working on a "steam canon" in his day that operates in a similar fashion. Injecting water into a heated chamber and utilizing the rapid expansion to fire a canon ball....

I don't think a working canon was ever built, but I can see this aplication may have a chance.

Eric

lerman
12-18-2006, 10:29 AM
Years ago, I had a friend who was interested in steam cars. If you google "monotube boiler", you will get lots of hits:

http://www.lynxsteamengines.com/

A monotube boiler is a coil of tubing that has water injected in one end and steam coming out the other end. The key is that it has a low internal volume, so it doesn't store a lot of energy that can explode.

The link, above, has articles on converting lawnmower engines to steam using a monotube boiler.

My guess is that would be an excellent fit for your application.

Ken

aubrey
12-20-2006, 05:55 AM
Is there a total lack of wind there?
Hi Russel.
There is wind - every other month - just enough to make you think that "cool" may exist.
Seriously, the normal farm windmill borehole pump only manages a couple of liters and then the wind is gone.
Aubrey

aubrey
12-20-2006, 06:23 AM
Hi aubrey,
Best of luck with this project, its very interesting.

Im just wondering how your calculating the piston diameter in relation to the size of your steam chest, and the size of the steam storage, and generation rate, in relation to the expected piston movements (rpm) ?

I dont know anything about engineering one of these but in your pic above the piston looks very large compared to the steam box. I'd think that maybe the steam box should be larger....

Hi and Thanks.
The drawing is not to scale (done with MSPaint - still need to get my head around 3dmax)
As to the sizes etc - all it must do is irrigate the same area (about 1/4 hectare or 50 x 50 yards) that 10 people are currently doing using buckets with 1 guy on the machine and 1 on a hose. Not high pressure, just a small flow maybe 5 to 10 liters/min (1 to 3 gallons), just enough water directly around the base of the plant to sustain the plant. No high pressure spray irrigation.
Currently 10 people each carrying about 15 liter in a bucket at about 5 minutes per bucket do the job in about 6 hours and it is back breaking work - especially in the tropical heat. The aim is to have 2 guys do the work which will release the rest so that they can go to school.

aubrey
12-20-2006, 08:32 AM
Hi Ian


First off it would severely limit the weight and size that you can make it to.
Valid point. However, the unit only needs to pump about 2 to 3 gallons a minute to a head of maybe 10 to 13 feet to make it successfull.



Secondly it would have to be fired up and cooled down which would make it awkward to use.
Nice point: mount it on its own trailer which could then be dragged to the next "irrigation point". (see below)

....fixed in position with the infrastructure around it to keep it happy, also someone will "adopt" it and keep it lovingly tended to make it reliable. Some people just get "broody" that way with machinery.
Each familys plot is at least 500 yards away from the next (to allow for firebreaks and cattle grazing etc) so a fixed central position would require excessive piping etc.
Nyrenere Mike (my Malawian partner in my transport business) came up with the idea of building a 10ft tower at each plot next to the well point (at 8 ft you get enough water) and having 6 or 8 44 gallon drums on the top with a simple interlinking manifold. One pump on a trailer could then move around the community filling the drums and then moving on to the next point.
The operators could get the necessary training and be paid by the community and the family could then do the actual watering of thier crop.


Looking back on the designs of the model railway engine builders, the injection pump should take the form of a displacement plunger pump where the piston doesn't actually touch the cylinder bore but displaces the water by it's intrusion into the pumping space.
This will prevent lack of lubrication on the pump piston from failing it prematurely, or causing the "boiler" to coke up due to oil being burnt there.
These pumps are usually driven by the axle of the loco and have to pump against boiler pressures of about 80 - 100 psi.
They are a bronze casting with a stainless steel ram and have a long wear life, very reliable. Gland sealing is effected by either Viton "o" rings (high tech, not recommended due to hard to get etc) or just greased braided yarn,cotton fibre etc.
The design is very simple and can be cast in the backyard type foundry and machined in very primitive simple machinery, even a drill press.
I would recommend that the firebox be made from cast iron so that it can be fired up and hold the heat while the water is just injected at a controlled rate to give the flash steam volume.
If the firebox/boiler is cast as one piece, it can be made to a simple pattern, by the dozen, with minimum machining, to enable it to be bolted on and off for simple replacement when it scales up or corrodes out.
The piston cylinder bit may be tricky, due to lubrication requirements.
Here I would use a large two-stroke engine (vespa scooter 150CC ?) with the transfer ports blanked off so that piston lube can be added to the steam supply and totally exhausted to prevent boiler contamination, and crankshaft lube contained in the sump off side.
Using a car type engine has too much mass and lubrication of the bores and big ends and main bearings would be a serious problem, where hot steam and water in quantity were present.
In this endeavour I would strongly advise contacting someone in the live steam model railway fraternity, and pose the scenario that you intend to pursue.
Ian, this is what I am looking for - - dont know of any steam clubs up here but I'll ask my brother-in-law. He's into old farm tractors and maybe he knows of a steam club up here in Joburg

aubrey
12-20-2006, 08:35 AM
http://www.lynxsteamengines.com/
The link, above, has articles on converting lawnmower engines to steam using a monotube boiler.
My guess is that would be an excellent fit for your application.
Ken
Ken - you are a star:cool: :cool:
OK - seems like the concept will work

thkoutsidthebox
12-22-2006, 08:41 PM
I hope this doesn't detract form the spirit of the thread but its something to consider...:)

Why do you need steam at all?....It would probably be easier and just as effective to just make a hand operated pump with a BIG wheel to be turned by one or two people. This would remove the need to gather firewood for one, and still dramatically reduce the amount of hours spent using buckets for irrigation. Im sure with a good gearing mechanism the operation would not be tiring at all, and you could pump the same amount of water as a steam system, except it would be a simpler operation. If someone is going to adopt the unit anyway he might as well operate it manually. They could also switch around for 5min turns if they want, or if not then thats fine too, as I said with the correct gearing it wouldnt be very tiring.

I know it wont look as good bringing it to your friend, but it would work and probably be more robust and durable in the long run being out in the elements with minimal maintenance. The 'technology' has been used long before steam ever made an appearance. Also it could be made almost entirely from wood, so that if it breaks they could even make replacement parts themselves locally using primative hand tools.

handlewanker
12-22-2006, 10:46 PM
Hi THK, have you ever had to work in the tropical heat?
In australia we are currently in a drought situation and the summer temps frequently reach 35 deg C.
Too damm hot to work that hard, even if your life depended on it, which means using the brain instead of the brawn.
The steam project is definately viable provided it can be brought together.
AUBREY, the problem with piston and cylinder technology is lubrication of the piston and cylinder, and making sure when you have reciprocating masses that bits don't fly off.
In 1910 the British admiralty under Lord Fischer changed over from triple expansion reciprocating engines to steam turbines to drive the Dreadnought type battleships.
If you are going down this path, of steam production, then be aware that you will be producing steam at superheat temperatures and in rapid quantities that without carefull controls just becomes lethal.
I think possibly a low pressure steam turbine would suit your needs and with only one working part becomes a simple mechanical device that could handle a fluctuating steam supply without blowing a gasket or seizing up due to lack of lube.
Have you considered the other end of the energy spectrum, and that is to exploit the vast amounts of dung that african society generates with cattle, animals and humans being the main producers?
Dung can be used to produce methane gas that would drive a conventional engine without modification and also be used for cooking etc.
The women and children could collect the dung from around the living areas, so reducing the fly population etc, and minimising the need to cut wood.
Ian.

thkoutsidthebox
12-22-2006, 11:17 PM
Hi THK, have you ever had to work in the tropical heat?......Too damm hot to work that hard....you will be producing steam at superheat temperatures and in rapid quantities that without carefull controls just becomes lethal.

I have to admit that I never had the pleasure. :)

But it seems to me that these people are working for 6 hours in that heat carrying buckets of water anyway. Maybe its just me, but I'd prefer to stand in the shade of a tree or umbrella or whatever and slowly turn a handle instead of plonking back and forth carrying heavy buckets.....Maybe Im alone in this view? :rolleyes: ;)

Its not exactly 'work'. If geared up and attached to a 4ft diameter wheel the handle could turn really slow. You could even ditch the handle and use a set of bicycle pedals and chains instead so everyone could sit down and enjoy the nice weather. :D

thkoutsidthebox
12-22-2006, 11:28 PM
...or gear a smaller handle to the bigger wheel so you dont have to stretch turning a big 4' thing! Just sit in a seat and turn an 8" handle which turns the big wheel which is geared to the pumping mechanism. All solid gears for durability, but they could be old fashioned wooden ones like on the old water mills.

handlewanker
12-22-2006, 11:50 PM
Hi THK, when it's 35 deg C+ in the shade, you don't want to be turning no 'ol handle.
I suppose you could always pump at night when it's cooler, but then the bl##dy lions would get you.
Ian.

thkoutsidthebox
12-23-2006, 08:16 AM
I suppose you could always pump at night when it's cooler, but then the bl##dy lions would get you. Ian.

LOL...:eek:...lions?....Fair a'nuf! I have succumbed to those more knowing. Was just an idea. :)

thkoutsidthebox
12-23-2006, 08:39 AM
Aubrey have you seen this link, undoubtedly some knowledgeable people in it who may not have come across your own thread yet.

http://www.cnczone.com/forums/showthread.php?t=301

T.L.A.R. eng
02-10-2007, 11:54 AM
Aubrey, just wondering if there is an update on your engine or circumstance with water? Have you been able to prove your engine concept?

aubrey
08-03-2007, 03:28 PM
Hi all
Thanks for the comments and suggestions.
Unfortunately I have to report that the project has been shelved.
The guy I was doing it for was Mike, my partner in a small (one vehicle) transport busness.
A short time ago, the vehicle was involved in a very serious accident in Zimbabwe. Mike seriously injured, vehicle was a write-off. Anything of value was stripped off and stolen.
Nett result: Mike is busy recuperating in Malawi, vehicle was retrieved but the insurance policy had so many loop holes that.... (need I go on?)
Needless to say, I'm left with 3 more years of payments on a vehicle that in reality no longer exists. (And that is after the insurance payout - less all the deductions as per the terms and conditions of the policy - it makes me sick!)
The "proof of concept" (much hacked Clinton 4hp lawn mower motor) did run under its own power for about 20 revolutions (The "boiler" was less than 1 liter total volume with about 100 ml of h20 and the fire also small - didnt want to have an explosion.)
So it did work - no info about power or anything - and its been moved under the workbench untill Mike has recovered from his injuries and I have recovered from my debt.
Once again to all who contributed, a big thanks.
A

handlewanker
08-04-2007, 04:56 AM
AHHHHHH Geeeeeee, Awb, just when we were waiting for the bells and whistles of latter day technology to blow.
Does that mean that the people are going to string you up or use you as a dart board for arrow practice because the crops are going to fail?
Whatever happened to Plan B?
You must have a plan B, every good plot has one, so what are you gonna do now mate?
I would like to venture a last morsel to tempt the alternative thinking of the "mob".
Bearing in mind that we are now faced with a manual approach to fetching water, would it be feasible to construct a tread mill type of drum out of wood, that allowed 3 or 4 people abreast to just slowly walk the water up hill, using a chain bucket system or archimedian screw, to fill a tank once a week, and then just draw the water as needed for a day to day basis.
Even in the heat of the day, walking in the shade of a large open ended drum for a few hours would be like walking in the shadow of the forest trees on a foraging expedition, and at night the wild animals would be held at bay by enclosing the end.
So we're down but not out, what next sport?
Ian.

aubrey
08-04-2007, 05:16 AM
Hey Ian
This has been a rather serious blow.
One Mike has recovered, he will be coming back to SA and we will look at taking this project on again.
At the moment, I am financially screwed (again).
As I said in my post, the unit "been moved under the workbench" and not to the rubish bin so there is hope that something will rise out of the ashes.
In the meantime, I have to do everything to knock the debt out and this unfortunately includes doing "private work" (mainly website programming and troubleshooting) untill all hours of the night. As you will appreciate, this cuts into my "personal workshop time" 100% but thats the way it goes.
Anyway, thanks for the interest and go well down the line.
Best
Aubrey

handlewanker
08-05-2007, 08:38 PM
Hi Aub, hang in there bebby, life is a bummer from time to time.
We'll be waiting to see how you make out.
All the best.
Ian.
PS, I still think the treadmill would work, it would aso serve as a community service deterent for the young tearaways who need a bit of discipline but not prison time for minor misdemenours. LOL.

spoiledbrat
08-05-2007, 09:31 PM
During my last two tours in Iraq, I noticed something fascinating. There are Bedouin tribes living in tents, with home-made everything, and usually, a generator. They have swamp-coolers (fans that blow through a water saturated medium), lights, etc., and were probably wondering why US helicopters were flying around.
Yes, in the deserts of Iraq, even the gypsies living in tents have diesel generators and diesel pumps. Although they rely heavily on these newfangled inventions, they are still able to live as primitively as they so desire. I would like to say that for solid reliability, and lowest operating cost, diesel is the answer. Maybe something could be "thrown" together for $100, but the idea of it lasting more than a year seems like the makings of a fairy-tale. However, a $400 generator, a mechanical pump, and $300 worth of fuel could easily last a year with minimal maintenance.

Seek donations.

Rob

dpete
02-16-2008, 09:50 PM
Have you thought instead about abandoning the steam idea and trying gasification instead? If you have wood available, then a gasifier wood be able to provide a flammable gas that a gasoline/natural gas/even diesel generator can be run off of. I read (somewhere) that during WWII 80%+ of Denmark ran off of gasifiers. And a great deal is already known about the technology, since it has been around since the 1700s.

jherzvt
04-11-2008, 09:35 AM
I applaud your work on this issue. I know something of what you are up against, and whatever happens in your life, I hope the prototype stays under your bench and is not discarded. You never know when you will get a chance to get back to it.

human powered irrigation is VERY well researched. It would be reinventing the wheel to work out another alternative to what is out there. If that is the way you are going to go, I would look at the two cylinder treadle pump. It was developed in Bangladesh, and there are now variations at least in Tanzania, Kenya, Zimbabwe and Senegal that I know of.

A lot of people have worked on the monotube boiler. It is attractive both for its inherent safety and its speed of firing. The key to getting it to work is control. There is a huge stretch of tube in the middle which may contain steam (an therefore be a superheater) or may contain water (in which case it is like a boiler watertube). heat transfer to water is much better than to steam so the tube is hotter when it is in contact with steam. When you start consuming steam, water enters the superheater section and there is immediate heat transfer as the water cools down the tube. Water flashes to steam, you get a pressure spike and often priming (where water comes out the steam pipe). All of that is going to be a lot harder to control with wood fuel than with liquid fuel. I think that usually monotube boilers are fired with liquid fuel so that the control system can change the heat input in a matter of seconds with a valve.

If you get back to this project and if you make progress on the problem of a wood fired monotube, PLEASE POST. A lot of people would be interested.

Jonathan Herz

handlewanker
04-11-2008, 10:33 PM
Hi all, one of the problems with the monotube boiler is that it likes to work under constant conditions, I.E. fixed water/fuel supply.

The moment you start to vary the supply rate you get all sorts of imbalances, such as hot water at the outlet, pretty lethal if you're running a steam turbine.

The best solution is to have a monotube boiler, which is the simplest steam producer known, (comments invited), of a capacity that produces the maximum wattage reqd etc, and have a secondary adjuster, that is a steam producer tied to a generator that feeds a battery bank that supplies the load, and can be varied as the load fluctuates, no load, no power drawn, peak load, generator and battery bank fulfilling the need.

It doesn't really matter what fuel is used to heat the boiler, as long as it is relatively free from contaminants that would clinker up the heating space.

One chap in the USA produces his own electricity with the excess going to the grid, and has access to sawdust and this is blown into a boiler firebox like liquid fuel, and as it's a waste product it was at the time just being got rid of.
Ian.

handlewanker
04-11-2008, 10:44 PM
BTW, anyone who has friends in South Africa will know of the power "outages" that are now a daily occurrence since Eskom went a bit peculiar.

I reckon if Aubry reinvented his idea with the aim of having a small generator, 12 volts?, driven by steam fired by wood, he would find a big market down south, as that is where the money lies to fund the project.

He might even be able to export them to Zimbabwe for the small sum of about 100,000,000 Zim dollars, about 10 dollars anywhere else since Bob went haywire with the economy.
Ian.