Flash Steam

A very simple question from me for once, but still daft no doubt.

Do you need a boiler certificate for Flash Steam / monotube boilers?

Does this mean getting insurance for using anything powered by a flash steam boiler would be problematic?

I'm still thinking of unusual methods of powering a Steam Wagon (not a faithful replica of an existing model obviously!) and as the Doble steam cars used flash steam (powering a 2 cylinder double acting uniflow engine if wikipedia is to be believed) I think it could have some potential.

Thanks,

Jon.

Hi Jon

Your local club inspecter will not certify flash steam boilers so you would need to have it tested and insured via a specialist company.

What is the volume and design pressure? May fall within the same 2 bar.litre exemption that applies to aerosols ets, and therefore not be considered dangerous under the regs. Must say my knowledge of the regs is based on the 2002 regs, and in the six months I was designing the box they applied to, 4 of the seventy applicable regs changed. It is entirely possible that none of the regs applicable then, apply now. So more up to date advice would be better than mine.

Regards

Richard.

Where is Windy when you need him?

As I understand it the actual water capacity is restricted to what is within the coils at the time, which is likely to be a cupful!

Jon Lawes,

You are quite correct in your description of Doble steamers. Another steamer called White, was I believe, a flash steamer. Both did cars and I think Doble did buses as well. The better known Stanley steam cars were not flash type. They had a large diam. barrel bound with steel wire and umpteen firetubes. When the steel wire rusted and lost some strength, the barrel would likely be vulnerable to such a high pressure. Fairly recently in USA some experimentation has gone on but finally abandoned, I think the big problem is the amount of fuel used to boil the water to travel a given distance, can be burned more efficiently in an ic engine, resulting in a greater distance travelled.

Are you a club member? Can you ask the boiler testers, maybe obtain or borrow a copy of the SouthernFed testing regs or Northern Assoc

John

I've finally plucked up enough courage to visit a club this wednesday, I'm looking forward to chatting face to face with like minded souls.

I'm currently just juggling ideas; I like the idea of building a steam wagon but want to make something that looks like it could have been made in-period despite being to my design. I've a lot of ideas rattling around but nothing concrete forming yet!

Thanks,

Jon.

Yes Jon, the pump(s) push water in to very hot small bore tubing and it flash boils to steam, so if the tube bursts, a small jet of steam escapes. Non flash steam boilers hold a large reservoir of very hot water where the boiling point is way above the 100 degree which only applies at atmospheric air pressure. If a barrel is ruptured, the sudden release of pressure down to the surrounding atmospheric will result in all of the hot water instantaneously boiling to steam at many times the original volume. Lots of big bangs, deaths and injuries years ago but proper specs and testing has made the bombs safe. I wouldn't think that relatively safe flash steam boilers would give rise to much concern but you do still need to make sure about specs and insurance. Perhaps you could enquire about the recent replica steam cars that have appeared and find out how they get on with testing and insurance. HTH

John

Very helpful indeed, thanks

Have been involved with another project as far as model flash steam tethered hydroplanes a boiler certificate not required.

It's a steam generator I have had email convesations with various full size flash steam car enthusiasts in the past and it can be a grey area.

As one flash steam car man said there is very little to test apart from pressure but if a pressure fitting was to become detached could cause injury so he recommended having third party insurance that might open a can of worms.

Have decided more because of health and traveling distances to call it a day with the model hydro this year if conditions change might have a last run at Kingsbury later in the year.

After that will sell all the model hydroplane bits there's the boat, video's, spare parts, generators and all the writings of the good and bad modificatios.

I know it has done well over 130mph if it can be kept on the water.

Am now more involved with full scale motorcycle speed attempts something I have a lifelong interest in and with my spiritual speed record venue on my doorstep that takes my time.

Next top speed event at Elvington Tuesday 19th June

Edited By Windy on 04/06/2018 00:14:16

Edited By Windy on 04/06/2018 00:18:51

Thanks for the confirmation Windy.

Still not sure if Jon would want to risk sitting behind a flash steam setup like yours

Section 2.5 book 2 of the new UK code (under 3 bar litres) states that flash steam boilers may not be tested under this code.

So, the code says what it can't be treated as, but does it say what it can be treated as? I'd imagine the answer is no...

Regards,

Richard.

Understandable as there are no litres to multipy by so you would get a zero value for Bar lts. Also as the outlet is open is it really a pressure vessel? From Windy's responce it seems they do not need certifying.

I'm sure you would still need some sort of safety valve so maybe that needs to be certified in some way?

It's a very grey area, until I asked here I was getting very conflicting opinions.

With my new full scale project I know there will be some hassle for its generator it can depend on your insurance company have found you must stress it's a generator.

There are plenty of certified safety valves about but I found any pressure release at speed causes overheating of the tube.

If the various mechanical control systems like Dobles or modern electronics can be used that might be an answer.

If you can get Doble Steam Cars, Buses, Lorries and Railcars by J.N.Walton it's worth reading but can be a bit pricey. .

The photo taken of a steam bike this year is a mixture of old mechanical technology and modern electronic control systems.

Sit in front of it but might need asbestos underpants.

I was quite impressed at one of the steam car flash boilers, I think it was doble, who had a system of quartz rods that pushed the control valves for the fuel supply shut as the temperature rose, providing closed loop feedback control for the heat supply.

I'll probably still end up going the route of a conventional boiler but the draw of exploring "the Sentinel that might have been" is pretty strong!

My Midland friend has built a flash steam generator based on a Doble design to use the thickness of tube the Doble has you need some powerful bending machines to create the rows of Catherine wheels.

Edited By Windy on 04/06/2018 17:23:31

Can anyone spot the difference between that photo and the one on the cover of MEW 231?

Neil