Vertical Boiler Fittings

To cut a very long story short: I tried every which way I could think of (apart from using an electric blower) and just could not get the boiler to consistently raise steam on solid fuel.

I got pretty close yesterday, and the steam blower worked spectacularly, but I tried all afternoon again today and couldn't repeat that.

As Peter (aka Gas_mantle) thought from the outset, this boiler is probably too small and has too few tubes to be a realistic proposition on solid fuel. He has nevertheless been very supportive of my efforts with this and has given me much useful advice on the basis that I wanted to give solid fuel firing my best shot.

So... time to draw a line and switch to meths.

More to follow...

Edited By gary.a.ayres on 29/12/2018 18:47:46

Currently working on the housing for the Trangia meths burner.

I cut the flared end off a ductile cast iron water pipe and faced the cut end:

Twenty minutes with an angle grinder and five million years with a file...

...plus spotting through the holes in the end cap from the old solid fuel firebox using my new transfer punches, and drilling and tapping resulted in this:

Beginning machining a slab of brass for the base (and showing off my Christmas present):

And that's it until tomorrow.

Not too bad a day's work I reckon.

Continued with the meths burner housing today.

Drilling the fixing holes for the base:

I'm liking my new transfer punches:

The various components - the housing, the burner plinth and the Trangia alcohol burner. The ductile cast iron water pipe end which forms the main body is lined with a tough plastic material. I like the blue colour, which I think goes nicely with the brass base and aluminium plinth, so I decided to keep it. There's a fair chance it will start to melt or scorch from the heat and need some attention, but I'll cross that bridge if and when I come to it. The exterior was painted with black stove paint :

Almost complete now - I just need to fix the various components together:

Here it is with the boiler in situ. I tested the setup a few evenings ago with a jury-rigged version which was almost identical in principle, so I see no reason why it shouldn't work. However, if the height of the burner needs to be changed, the plinth can be adjusted, and if it needs more air, holes can be drilled in the housing. Hope to have it all fixed together and tested sometime over next weekend:

gary

I was unhappy with the number of flutes in the column of the burner plinth I made yesterday so I made a new one with 12 divisions instead of 8. 

However, while I'm pleased with the overall look, there are still a couple of aspects of that plinth I'm still not overjoyed with, including the standard of milling of the flutes, which I know I can make a better job of.

I might redo this part yet again, but I'm going to test it for optimum burner height before I do.

Edited By gary.a.ayres on 02/01/2019 22:54:37

Well... I tested the above arrangement today, only to find that the setup would raise but a meagre amount of steam. Not enough though!

Trying the Trangia at different heights relative to the bottom of the boiler did make a bit of a difference, as did the steam blower, and the beginnings of steam made themselves apparent, but the pressure gauge held resolutely to zero.

Was it because the Trangia was too shut in and not getting enough oxygen? The next experiment should help to clarify that (Trangia, with boiler supported by an open framework).

Noteworthy though that again today my primitive four wick meths burner did raise decent steam ( as per video above), albeit perhaps against all odds. Maybe a way forward...?

And a forum friend has encouraged me to consider gas as an alternative. Well, no harm in keeping one's options open, I guess...

This is all more tricky than I expected but I'm not out of ideas yet...

Will keep tinkering, and post the results...

Gary,

Never having heard of a Trangia burner (sheltered life maybe lol) I consulted Mr Google! Many of the comments re suggest they are slow to boil water in a pan. I get the impression they have a relatively low heat output so in terms of a burner design for steam raising? I have not seen one burning but imagine there are many small flames from the various holes? Have you thought about a burner along the lines of the old paraffin stoves with a 'ring' wick and a large circular flame? They were designed to chuck heat out.

Paul.

Hi Paul -

I have never been given to living the high wild life either... well, not huddled round a Trangia at least 

You may be right - I'll find out when I test the Trangia in a more open setup where there will be plenty of airflow.

My crude four wick burner does the job in any case, though the flames seem a bit out of control.

Thanks for your suggestion - while I was following it up I came across this:

https://www.amazon.co.uk/SODIAL-Universal-Outdoor-Kerosene-Camping/dp/B079DLNGSR/ref=pd_sbs_200_4?_encoding=UTF8&pd_rd_i=B079DLNGSR&pd_rd_r=c42a1a25-10d6-11e9-9db3-5db3b63ef36d&pd_rd_w=oEhgG&pd_rd_wg=f8Nfy&pf_rd_p=18edf98b-139a-41ee-bb40-d725dd59d1d3&pf_rd_r=X4RRWY2BEGHHST4X8W60&psc=1&refRID=X4RRWY2BEGHHST4X8W60

I know it's not the same as what you suggested but at that price it's definitely worth a try with a couple of modifications, so I bought it. If it doesn't put out enough heat it will still give me plenty of bits to play around with.

Will report back here in due course.

Thanks again.

Edited By gary.a.ayres on 05/01/2019 11:00:25

Following my unsuccessful attempt (details above) to raise steam with the Trangia in a partially enclosed housing, I made a new trial setup which is wide open in structure and tested it this evening. I decided to simply fire it and wait and see if it would get the safety valve to blow off. This evening, the Trangia slowly but surely raised steam. It took 50 minutes from cold and just over one fill of the burner with alcohol to blow off the valve without using the steam blower. The suppliers of the valve told me it was rated at 45 psi, but the gauge showed closer to 70 by the time it blew. How accurate the gauge is I do not know. I then played around with the steam blower for a bit and enjoyed the definite way in which it pulled at the flame. The Trangia throws out less heat than my crude four-wick burner but it burns in a much cleaner and more controlled way.

This was hardly a controlled experiment as I carried out this evening's test inside my workshop whereas the previous attempt took place outside. I am therefore left wondering whether tonight's firing was much better because of the burner not being shut inside a housing or because being indoors the flame wasn't being blown around (although there wasn't much wind the other day). It will be easy enough to check this tomorrow evening by firing it under the same conditions as this evening but with the burner inside the housing rather than open.

A little bit of a feeling of progress this evening. Picture below:

I'm one of the nutters who used to commune with the clouds. Meths Trangia would boil a pan of water in a lot less than 50 minutes, we'd have got bored and given up long before that. I seem to remember a much bigger flame than you show above, but it's all a long time ago. For day trips a thermos flask was a lot easier.

I have the gas equivalent if you want to borrow it, but buying one might be less than the postage.

Hi Duncan -

Yes, I haven't tried the Trangia on a pan of water, but I believe it should boil one in about 15 minutes. I guess it's the all-important psi of steam pressure that makes the difference here. I'm new to this, but I'm guessing it could have had a small engine running quite a bit sooner than 50 minutes.

Many thanks for your kind offer, but I have ordered a gas burner that cost eleven quid and is already on its way. The plan is to have fun customizing it. I suspect it will fire up this boiler pretty fast.

I have also ordered an eight-wick kerosene camping stove to try, but I think the ring might be too big. At a tenner, though, it's a risk worth taking. I'll find out when it arrives.

At the moment I'm just trying out different firing methods with a view to ending up with a few interchangeable options/burners. I'm drawn to simplicity (e.g. meths rather than pressurized gas containers, etc.), but have come to realise the need to be practical. It took me a while...

Cheers,

gary

Lagging the boiler will make a significant difference too.

Neil

Neil - yes, I'm sure it will.

Cheers.

My multifuel adventures continue.

This evening I tested the Trangia inside the cast iron housing which features a few posts above. It was tested under very similar conditions to the open structure I tried last night, i.e. indoors, same burner height, similar amount of water in boiler. Last night with the open structure it took 50 minutes from cold before the safety valve blew off. This evening with the cast iron housing an hour and a quarter in and still nowhere near. There was also an acrid smell - not overpowering but unpleasant. I'm not sure if this came from poorly combusted alcohol or from the plasticky paint inside the housing, but I gave up the ghost and turned off the heat. So, even though I thought that the housing was plenty open enough, clearly it wasn't, so I'll use the open structure if and when I fire the boiler with the Trangia in the future. I guess this could be an option for indoor use.


Meanwhile, look what landed in my back yard today:



Hitherto I have resisted gas, but I took some good advice and decided to cut myself some slack and keep my options open. When I saw how furiously this bad girl burns when you open up the throttle, I realised why it's a popular option. Doesn't look like raising steam will be a problem

Mods have already begun on the gas burner. I know each situation is different, but any advice on the optimum distance between this standard size burner and the bottom end plate of a 3 inch boiler will be welcome...

gary

Looking at Gary's boiler I see a massive heat-sink. The heat (from whatever source) has to lift the temperature of the boiler's metalwork as well as the water inside. Once the water approaches boiling point, significantly more heat is needed to make steam - a lot more. The boiler has a large surface area extended by pipework: if you wanted to heat a room it makes a decent radiator. Also, with only five short tubes, I would expect a lot of heat to go straight up the chimney and away. Gary has also used a lot of metal in legs or the burner: these also are likely to soak up and waste heat.

It's possible to measure how much heat is wasted by filling the boiler (burner off) with a known volume of boiling water from a kettle and - with a thermometer - measuring how long it takes to cool down. Without bothering with the sums, the more rapidly the temperature drops, the more the boiler is wasting heat rather than raising steam.  Compare the boiler's rate of heat loss with a thermos flask and the kettle.

I think it well worth insulating the boiler before trying anything else. Wooden strips on top of a layer of felt if the thing is to look good, but for experimental purposes I'd lag it in several layers of loosely wrapped aluminium kitchen foil. Blanket is an alternative but is a fire risk. I'd also start by filling the boiler with hot water from a kettle - if the burner can't keep the water boiling, it's never going to work.

Slightly worrying is what happens if a marginal boiler is asked to run an engine. The engine works by cooling steam, in effect adding a hefty thermal load to the boiler. At that point the flame has to transfer enough extra heat to keep the engine going.

In full size steam they pull every trick in the book to improve heat efficiency.

Dave

Edited By SillyOldDuffer on 14/01/2019 11:30:01

Uh-oh...

Dave, your message is sobering but important, and so is appreciated.

Funnily enough, I was wondering about this only this morning.

Following Neil's comment above and similar from another member, I already have my eye on this:

https://www.glrkennions.co.uk/boiler-lagging.html

I was going to leave it until later but I think it has just jumped the queue! I was aware that lagging is important, but perhaps not just how important it is. I guess I could just tie it on with wire in the first instance.

On your point about the heat escaping up the chimney - would it be helpful to put a twist of copper down the chimney (or the central fire tube)? I understand that can help sometimes...

I should reiterate that on my only testing on the gas burner thus far it certainly boiled (as it did on meths, though more slowly), and I had no sense that it was running out of steam before I shut it down. It seemed pretty fierce to me when the safety valve blew off, and afterwards. However, the real test will be with an engine, as you suggest.

I have not yet made an engine, but am thinking I should now get started on a simple single-acting oscillator to gain much-needed experience and test the boiler. Again, I was going to leave this until I have developed the boiler further but perhaps again I should shift focus. I have my eye on this version:

http://www.steves-workshop.co.uk/steammodels/simpleoscil/simpleoscil.htm

It's 12 mm bore. My plan was to build it double size but if the viability of the boiler is really in doubt, I'm wondering if I should stick to 12 mm in the first instance. Any thoughts on this question would be most welcome.

Edited By gary.a.ayres on 14/01/2019 11:58:28

Edited By gary.a.ayres on 14/01/2019 12:00:53

Edited By gary.a.ayres on 14/01/2019 12:01:39

Hi Gary,

It's a good looking boiler and - if you can get enough heat into the water - I'd be amazed if it couldn't run a steves-workshop oscillator - they don't need a lot of puff. I've built a few more elaborate engines and run them on air - quite instructive because of two identical PottyMill engines, one runs freely on 5 psi, whereas the other takes 10. It's the better made version that doesn't work so well - it's a bit stiffer and I think the valve is leaking. Working out exactly whats wrong has so far defeated me!

So far I've been too cowardly to attempt a boiler: I had something in mind very like yours which makes your experience so interesting.

I don't know if adding copper wiring to the tubes will help or not. I know there's an optimum length diameter ratio, and number of tubes for a boiler, but not what it is in a model. What's needed is for the hot gas to be in contact with the tube for the time needed to transfer maximum heat. For full-size boilers it can be calculated. Models don't scale, and experiment is necessary. I'd copy an existing design - the old guys tried all sorts of combinations.

I'm self-taught and clumsy. When attempting stuff, I've found it pays to start with something simple. The less there is to go wrong, the easier it is to find errors! I would stick with the 12mm oscillator design, partly because someone's tested it already, but mainly because it will need much less steam than double size - the volume required rises with the square of the cylinders radius. If 12mm works then try next size up.

No experience of Kennion's lagging. I'm sure it works but it's intended for looks as much as efficiency. If you don't mind about the appearance kitchen foil is a good insulator, cheap and to hand. Wrapping it loosely traps air between the layers and the shiny surface doesn't radiate. More layers the better. Fibre glass loft insulation is OK too. With luck heavy experimental insulation will improve the boiler radically, and you can sort the looks out later.

Good project.

Dave

Edited By SillyOldDuffer on 14/01/2019 12:32:12

Gary,

Whilst lagging is important and will have an undoubtable effect on overall rate of steam production it won't make your fire burn any better. Personally I think your experiments have followed the right route so far and if you can boil water and make some steam without lagging then when you fit lagging you can be confident it will boil harder and make more steam. Twisted shim in a tube or two is not a bad idea as it will slow the passage of hot gas through the tube allowing more heat transfer. It's worth bearing in mind that with a traditional loco type boiler the greater proportion of heat transfer to the water takes place as direct radiant / conducted heat from the fire through the firebox sides and crown than from flue gasses through the tubes. Some American design traction engines also had 'wet bottom' fire boxes to give another surface around the fire! Your activities with firing are very interesting to follow, giving some direct practical experience rather than theoretical speculation.

With the engine; why not start with the 12mm bore version and follow up with a 24? I am sure your boiler is well able to run the former and most likely the latter, it might even run both!

Paul.

Thank you both, gentlemen.

I feel a bit relieved now

I will prioritise the insulation aspect. Was thinking of using a skin of shiny aluminium sheet instead of wooden strips over the fibreglass insulation, just for a 'different' kind of look, but I agree - cosmetic considerations can be addressed later on.

I think you are right about starting with the 12 mm oscillator. If the boiler does turn out to be a bit of a lame duck, I'd rather have a 'to-scale' minor success than an upscaled failure! And if it runs the 12mm well, then I can always go bigger as you both say. The Pottymill is on my list, as it happens.

Your input is much appreciated

This evening I decided to actually try running the boiler rather than just heat it up and gaze at it in stupified awe while it did its thing.

Using the gas burner, I took it up to 50 psi on the gauge. I had the gas turned up a bit higher than last night and it took me 10 minutes to reach 50.

I then opened the steam takeoff valve a bit, resulting in a steady jet of steam which made a narrow strip of paper which I held in front of it flap. The pressure stayed at 50 until I opened the takeoff a bit more, at which point it dropped a little, but it was easy to get it back up again just by restricting the steam out a bit and/or turning up the gas. I went on like this for 20 minutes, with the pressure between 40 and 50 most of the time. At one point it dropped to 30 psi, but that was mainly due to inattention on my part I think. I pumped in more cold water several times and the system recovered quite quickly from that.

That said, the gas was turned up full for most of it, but this didn't seem to do any harm other than to use more gas...

When I get to lagging the boiler it can only get better...

After 20 minutes, I decided to have a fiddle with the steam blower. I was amazed at the dramatic effect it had even with the gas turned up full. The gauge went up fast, and looking up into the bottom of the boiler I could see the flame being sucked up the tubes. I think the blower on this boiler might be useful even with gas.


I'm tempted to be pleased with this, but the one thing I do not yet know is whether or not that jet of steam will drive an engine.

There's only one way to find out...