Not enough steam

jamespetts · Not enough steam

After a number of modifications from last time, I ran my Stuart Score and 504 boiler again to-day (photographs and video to follow). Despite the fact that I had re-lagged the boiler with an second sheet of kaowool and an outer copper shell, adjusted the burner so as always to get a blue flame with light blue cones and a glowing red surface, and raised it to just below the water tubes, I still did not get much in the way of steam production.

When I was running the engine even at a really very slow pace (slow enough that very light pressure on the flywheel could stop it easily), the boiler was not maintaining pressure, and it would only ever increase pressure when no steam was being used at all. Running the engine with the valves fully opened dropped the pressure to almost nothing in less than a minute. There were no leaks in the boiler itself or the fittings (once I had tightened them, in any case), and only very small leaks in the steam glands and at one place in steam pipe to the engine.

I have yet to lag the main steam line (I waited to check to see there are no leaks), which should help a little, but that would not be enough by itself, I should have thought, to make that big of a difference, even in to-day's cold weather. There was, at least, no soot on the water tubes this time.

I was wondering whether the problem was related to how far into the firebox that the burner is: presently, the back end of the burner is just underneath the lowest part of the pipes, which is at the chimney end of the boiler. The burner does not go all the way to the other end of the boiler, so there is a fairly large area at the front (at the opposite end to the chimney) that is not getting heated directly at all: indeed, it is getting cold air rushing in from the front air inlet to feed the fire further back, the hot air from which is then going straight up the chimney.

Do people think that moving the burner back further into the firebox would help, or would that then cause problems by taking the heat away from the lowest point in the water tubes? Any other suggestions?

Les Marsh

What is the length of the boiler and the length of the burner??
I would experiment with the burner in different positions to find which one is the best place for the boiler, also check to see if the burner is actually the right size or do you need a longer burner.

Florian

Hi James

i've just watched your video on youtube.

If i have seen this right, then you are using your ceramic burner als a gas distributor (is that the right expression

) and your ceramic burner isn't glowing at any time, right?

After ignition and some time to heat up, a ceramic burner should look like that:

To repair your leaking cock drain, you need some patience and a little amount of toothpaste (the one with abrasive particles).
First, you have to remove your drain cock from your boiler
then you disassemble it and put some toothpaste into the conical bore and then you turn the rotating-piece (i don't know its exact name in english...) by hand for at least 10 minutes. (slightly pressing it into the bore...)
If you have processed all this, then you clean and dry it. Then color the shell of the rotating part with an edding (waterproof marker) and press it into the conical bore. If the bore has a spot without any color on it, you need to coninue grinding in.

Florian

Florian

By the way, what's the bore of the burner's nozzle?

Florian

jamespetts

Thank you for all of your replies

The video that I have on YouTube at present is of the previous run: I have modified the burner since then, and it does now seem to glow. I shall post a video of that in due course.

The boiler barrel is about 28cm long; the burner is 14cm long. It is the largest ceramic gas burner available (at least, that I could find). One solution that I am considering is obtaining a second, smaller, burner, and inserting that at the other end of the boiler so that there are burners covering the entire length of the boiler. Any thoughts on whether that would work?

Florian

Hi James

It might work, if you mount your burner with just 1 or 2 cm distance to the water tubes (But still horizontal!). A ceramic burner needs NO secondary air unlike any other burners. So you could take a piece of v2a sheet and then make a cover out of it so that the hot gases from the burner need to pass the boiler without getting mixed with any cool air.
Have an idea what i mean? If not, i'll make a sketch..

Florian

jamespetts

Florian

Here's your sketch

I hope its clear now..

jamespetts

Florian,

thank you - that is a useful sketch

One complication, though, is that the larger entrance hole is at the chimney end of the firebox, the gas pipe enters that end, and consequently the gas jet is located at that end, so the design that you suggest would clash with those components. Incidentally, from what material do you suggest that such a thing be made?

I have now uploaded a video of the engine in action for the second time, which can be seen here. Does that give you any clues as to the problem?

Florian

jamespetts

Florian,

thank you for your reply

I did forget to answer your question about the jet earlier, and your latest reply has made that more relevant - in the first video, I used a no. 16 jet, but replaced it with a no. 8 to get a better flame after advice from "Bogstandard" on these boards. Is a blue flame with little blue cones and the ceramic glowing slightly red not what I should be aiming for?

I shall look forward to seeing your video

DLR

just a thought but could your new cladding be stopping the heat getting past the boiler ?

Florian

Now this is how it should look like:

Video of my Ceramic burner

Florian

jamespetts

Florian,

thank you very much for the video - it is most useful! It gives a good idea of what the burner should look like. Mine does not look like that at all, which is probably part of the problem. I am wondering whether gas is leaking around the joint between the jet holder and the ring: when the fire blew back in the wind on one occasion, a small flame persisted at the join until I blew it out. I shall try sealing it with PTFE tape and see whether that helps.

DLR, I am not sure that I understand your suggestion - the whole point is that the cladding stops heat from getting past the boiler so that the boiler does not lose heat to the atmosphere. It would not, of course, stop heat from getting in, since only the top is cladded - it would be insane to clad the underneath!

Florian

Hi James

Could you make a photo of your jet and the fitting which delivers the butane?
You will have to try out how deep to position the nozzle into the nozzle holder (which is part of the ceramic burner).
I think this helps the most to decide wether your nozzle is the right size or not.
By the way, what bore do your nozzles have? It usually should be something between 0.2 and 0.3 mm.

Florian

Florian

jamespetts

Florian,

thank you for your reply

Here are some photographs of the ceramic burner jet ring and jet:

I have already spent a great deal of time trying to find the optimal position of the jet in the holder (and the optimal sized jet: I have tried a slightly enlarged no. 16, a standard no. 16 and a no. 8: I am afraid that I do not know their measurement in millimetres), and I thought that I had found it: what I was looking for was a blue flame with little blue cones near the bottom. Oddly, your flame seems orange: is that the right colour? I have only ever had blue or yellow flames. How would I go about obtaining an orange one?

I also conducted an immersion test to see whether I could find any leaks in the burner - see this video:

(click here if embedding does not work). I found that, as well as escaping from the top of the burner, through the holes, as it should do, air was escaping from around the side of the burner, where it is supposed to be sealed. There was also a slight leak (not shown on the video) between the jet ring and the jet holder. The latter leak I could probably seal with PTFE tape, but I imagine that the former is the bigger problem - how would I go about sealing around the edges? I cannot even see the holes...

Bogstandard

James,

If you look at Florians burner video, it shows what I was trying to explain. That is a ceramic burner working as it should. Small bunsen blue cones and an almost white hot surface on the ceramic, you can discount the orange you see, that is just unburnt gasses being used up. In normal daylight you would never see them.
A perfect video for explanation of what it should look like.

I looked at your leak test vid. Is the ceramic material in there very hard?, or powdery with a chalky feel. The reason I ask is that isn't the normal material used for ceramic burners. It is normally a series of little pyramids, with the holes in the valleys between them. If it was the same material as Florians and what I used to make them out of, it would be almost destroyed by what you did, it just does not like water.

I don't know where you got the burner, but it just doesn't look the norm.

John

Florian

jamespetts

Thank you both for your latest replies in this long-running saga! John, the ceramic material from which my burner is made is quite hard, but also a little crumbly. It does not seem to have been affected adversely by being submerged in water.

I bought the burner, jet, pipe and regulator valve from this website. The website does not give details as to what size that the various gas jets are: it just calls them no. 5, 8 and 16. There is reference to a no. 12 jet, too, but they do not seem to sell that one. John and Florian - where do you buy your ceramic burners from? Is it possible that a different kind of burner will give a different kind of flame such that mine will not look like Florian's whatever I do to it?

Florian, I have a day off to-morrow, so I will try testing the jet then. Do either of you think that the leaks around the edges might be a problem? If so, how would I fix those?

Florian

Hi James

If you have your burner from these guys, why don't you ask them how to adjust ist??

I guess they best know what to do or where the mistake is.

It would also help a little more, if you could make a short movie which shows your burner operating (but not under the boilers housing)

Just.. your ceramic burner isn't glowing at any time is it?
And in your first video, it looked like it was burnig with one big flame; it should be burning with tiny flames over every hole on the ceramic board.

Maybe you need to reduce the flow on the regulator...? Because if there's to much gas, the burner will not start glowing.

Florian

jamespetts

Florian,

thank you for your reply. Your suggestion of asking the retailer is an interesting one: I probably had not though of it because I did not know until I asked on the forum that it was maladjusted to begin with. Also, if the problem is simply that it is not a very good burner, I might not get an entirely straight answer.

I have made a short film as you suggest, which can be found here. This encompasses most of the testing that you have suggested: the burner seems to work very differently from yours, although it does feel very hot, especially when the gas is turned right up. Does this give any clues as to what the problem is?

Florian

Hi James

It looks like your burner is a bad copy of the real working ones...
What diameters () have the holes on your burner? Is it just the video, or are they very big?

Your Jet is allright.. But what's wrong, is the burner if you ask me! Looks like something in the burner would constrict the gas flow.
Now, there are three things you can do:

1. You sell the burner and buy another one
2. You remove the seal and then remove the ceramic element and then show me some photos. I'm shure we can find a solution to make it work better. To reassemble, you will need some ceramic mortar (ask a kiln constructing engineer for a small amount of mortar... please tell me the correct expression for this... i couldn't find it...)
3. you throw your burner away...

Florian

jamespetts

Florian,

thank you for your reply

A bad copy of a working burner - that is not a good start. The main air holes around the jet have a diameter of ~7mm, although the bottom one, which my father added, is a little smaller. As you will notice from the video, when I blocked the bottom hole with my finger, there was little change.

I am not sure what would be in the burner to constrict the gas flow- as I might have mentioned before, it has behaved in largely this way since I had it new. Perhaps the best solution would be to look for another burner? I notice that Maccsteam make custom sized burners, which would mean that I should also be able to have a burner long enough to cover the whole of the bottom of the boiler, rather than just part of it. However, with very long burners, does anyone know whether they are less effective as a result of the far end being so far from the jet, such that it would make it better to have two separate burners, each half the length of the boiler, with a jet each?

CCairns

As Forest Classics were voted the best steam dealer/retailer of the year 2007 by this Forum, I would certainly go back to them for advice. They do not list the instructions for these Bix burners on their website, but they are available from Ministeam here - http://www.ministeam.com/acatalog/Bixsettingthejetposition.pdf

jamespetts

Chris,

thank you for your reply

I already have the instructions - they came on a pamphlet with the burner. Unfortunately, having tried with two different jets and all conceivable positions, I cannot get the flame any better.