Flash steam with modern control technology

I have been reading the 1973 book "Experimental Flash Steam" about powering model boats using flash steam boilers. The high pressure, easy superheat, and fast startup make these boilers really interesting, but they are a little hard to control. I am wondering how you would apply modern control technology to a flash steam boiler, i.e. controlling the supply of water and fuel, regulated by temperature and pressure.

Maybe its been done already by somebody tuning their Stanley steam car, but I would be interested in ideas about how you would go about it. Could it be prototyped using a PC, using A/D units for I/O (which I have)? I have no idea about actuators etc, and have never dabbled in microcontollers. Some pointers in this area would be appreciated.

Thanks Cheshire Steve

Reply to
Cheshire Steve
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Alex Moulton did some work on flash steam IIRC, there was an article in Stationary Engine magazine a few years ago with a unit that he has constructed shown at the University of Bath.

Most of the control side would be easier with a PLC than a PC I feel, but thermal lag and other factors would also need to thought about.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

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Reply to
Peter A Forbes

Aha, so PLCs are the thing these days are they ? Hopefully the rampant charge of technology will have made things easier. Thats one thing for me to investigate.

Thanks for the tip on Alex Moulton. Anyone have an index for Stationary Engine magazine so we can find the article?

Thanks Steve

Reply to
Cheshire Steve

If you read this thread on Practical Machinist you will find an interesting description of a guy`s trials with flash steam.His name is Hendeyman and you would be able to contact him if you register for the group.

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Mark

Reply to
mark

There was a book in my local library on Doble Steam Cars, I borrowed it a couple of times. Flash boiler with 500ft tubing, kerosene fuel with a carburettor. Entirely automatic and steam raised in seconds from cold. 2 s/a cylinders on rear axle (uniflow?) so no clutch, gears, etc., mighta bin a diff. System returned 60% of condensate.

System was used in Henschel (1) rail locos following the demise of the car company, maybe still is. I seem to recall the cars cost 10x the price of a Rolls, only when the co. planned a "compact" model was it killed by dubious stock issue concerns. This was all in the '20s in California.

Between my 2 borrowings I came across a Stones generator in a knitwear factory when I was in my short chemical de-scaling career. I'd never seen one ande asked if there was a manual. It told me how to clean it.

Not a whiff of electronics anywhere, the logic of control was simple and it worked. Ther are Dobles which reputedly have covered 200k miles with simple servicing, one did 600k.

Temperamentality comes from trying to scale it down of course and trying to control a paraffin blowlamp.

Try this link

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then Google for more info.

(1) My spillchucker suggested "Headcheese"

Reply to
Ray

In message , Cheshire Steve writes

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A few years ago someone appeared with a full size, road legal, home built steam car at the Midlands Model Engineering Exhibition. It had full electronic control of the steam plant. I had a ride in it and, for all sorts of reasons the experience was memorable. Not least the memory of a spectator clearing "Whooomph!" when it started and the spectacular acceleration.

I recall it being featured in 'Engineering in Miniature' magazine shortly after, but my old copies are no longer easily accessible.

Reply to
Mike H

--One bunch you might want to contact are SACA West, which is headquartered in Los Angeles, CA, USA. Years ago there was a character by the name of Pete Barrett who put together a VW "kit car" with half of a VW engine that he ran with a flash steam system. Pete died last year and I'm not sure what became of the vehicle but it was a beauty: I got to ride with Pete once, a fascinating experience. 7% cutoff, IIRC. The guy to contact from SACA West (which is not affiliated with the larger SACA organization for some reason) is Ken Kowal; last known email address: snipped-for-privacy@juno.com There was quite a bit of research done on flash steamers in the '70s and '80s and most of it was written up in one of the US newsletters, not sure which one tho.. The heart of the system was a 'spinning cup burner' that, in operation, resembled the ass end of a jet plane with full afterburner running (!!). There were thermocouples and feedback mechanisms in the flash boilers that injected cold water to keep the steam temperature below a certain value, presumably to keep from melting the plumbing or galling the engine. Pete worked at an oil company and he managed to get a couple of drums made of a *very* special oil that readily seperated from steam, so that it could be recycled back into the engine without contaminating the boiler plumbing. Not sure what the stuff was and not sure what became of the stuff. --Another place to make enquiries: you might try posting to the steam car forum at

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Reply to
steamer

Ray,

Indeed the Doble was a Noble beast, and according to my notes it was a double acting 4 cylinder compound, with full piston valve control. Stephenson link motion had three cut off points, 80% for pulling away and steep hills, 60% for normal running and 40% for speed and economy (overdrive!!). The boiler weighed 484lbs with the burner (whereas the whole car was 4300 lbs), and provided 1330 lbs per hour of steam, at about 800psi and 800F (427C).

Apparently the Doble used both temperature and pressure in their mechanical control system, with pressure switching on and off the 1kW fan delivering air to the boiler, and temperature controlling the water feed pump/s. I think this only hints at the complexity of the system, and I don't have any more details - and the design may have varied. I suspect some of the large cost of the Doble was in this area.

Would I like a Doble - YES PLEASE ! Can I afford one - Probably not !

But at least this is a good example of the fun you can have with a flash steam boiler.

Steve

Reply to
Cheshire Steve

I stand corrected, and rightly so. No notes in front of me, just a memory from '73. I think the "compact" they were planning would have had the simpler engine. IC engine car manufacturers were not worried about a car no one could afford, but when Doble threatened to be serious competition they used all sorts of skullduggery to prevent it.

Another thing I recall about the Stone's generator was that it had 2 pumps, one for circulating (continuously I think, the steam drum had a centrifugal action for separation) and a make-up one. These were both diaphragm pumps with maybe rubber elements positioned far enough away, longish tubes between the diaphragms and their valves, from any heat that would destroy them, and controlled with solenoids. The unit I cleaned was used for Hoffman steam presses so it was a fairly light duty, but gave "on demand" supply, no usage meant it shut down until one was called. There were versions capable of 100 psi at not very large amounts and I was told some ships had them as auxiliary supplies.

Or I could be wrong, it's been known before.

ET Westbury had a lot to say about flash steam hydroplanes pre-war. Most problems were concerned with paraffin burners and the centrifugal effects of racing round a pole. Those fellers had loads of fun. Go for it.

Reply to
Ray

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