Author Topic: Cleaning boiler tubes.  (Read 4107 times)

Online Jo

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Re: Cleaning boiler tubes.
« Reply #15 on: January 09, 2018, 06:03:08 PM »
Sounds like poor coal..... What type are you using best Welsh steam coal or something of a lesser quality  :(

Blowers are only for starting a fire, once they are going then the chimney should produce enough draw.

Jo
« Last Edit: January 09, 2018, 06:11:59 PM by Jo »
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Online Gas_mantle

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Re: Cleaning boiler tubes.
« Reply #16 on: January 09, 2018, 06:14:53 PM »
Sounds like poor coal..... has someone been relieving themselves on it?

Blowers are only for starting a fire, once they are going then the chimney should produce enough draw.

Jo

I did wonder about the coal quality but the stuff I have is proper Welsh steam coal from a recognised UK model supplier.

The boiler does have enough draught without the blower once I have steam, I have modified it so the engine exhaust vents up the chimney.

Online Jo

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Re: Cleaning boiler tubes.
« Reply #17 on: January 09, 2018, 06:17:10 PM »
How small have you broken your coal up into? Smaller bits = greater surface area = easier (quicker) burning.

You would be surprised how smaller a lump you will need to be using on a boiler that size.

Jo
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Online Gas_mantle

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Re: Cleaning boiler tubes.
« Reply #18 on: January 09, 2018, 06:25:42 PM »
How small have you broken your coal up into? Smaller bits = greater surface area = easier (quicker) burning.

You would be surprised how smaller a lump you will need to be using on a boiler that size.

Jo

It's proper steam coal that is sold for smaller model steam locos, the lumps are the size of sugar cubes,

Excessive soot I think is because in the past I have been using pony poo and cheap wood to get it started before I had an electric blower.

With 5/16ths dia fire tubes I guess it is always going to need a regular clean out.

Offline Jasonb

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Re: Cleaning boiler tubes.
« Reply #19 on: January 09, 2018, 06:37:29 PM »
JB have you tried to buy paraffin in a normal hardware store? Meths is always available, BBQ lighter fuel is also ok.

I don't usually get that far as I can buy it from several local petrol stations and also garden centers. However B & Q and Homebase also sell it and they have replaced many of the old traditional hardware stores, look in the gardening deparments as it is used for greenhouse heaters

Online Jo

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Re: Cleaning boiler tubes.
« Reply #20 on: January 09, 2018, 06:49:39 PM »
Down here I spent ages trying to buy paraffin and if they had it no one knew about it. Was told at the local club not to waste my time and stick to the easy to come by stuff: Meths is the preferred stuff as it burns much hotter than BBQ lighting fluid.

Don't use wood :ShakeHead: it burns cooler than charcoal go straight to coal  :)

Jo
« Last Edit: January 09, 2018, 07:08:49 PM by Jo »
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Offline Zephyrin

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Re: Cleaning boiler tubes.
« Reply #21 on: January 09, 2018, 08:48:21 PM »
maybe the fire is not hot enough, too much incomplete combustion, try with the blower on permanently...

if the grate is large, (relatively as compared with a G1 loco!) you must check that the fire is distributed all over the grate and not limited in a part.
I personally use first meth soaked charcoal, then coal, never wood and the electric blower.
« Last Edit: January 09, 2018, 09:06:29 PM by Zephyrin »

Online Gas_mantle

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Re: Cleaning boiler tubes.
« Reply #22 on: January 10, 2018, 03:00:14 AM »
Thanks Zephyrin,

What sort of boiler are you using ?

I think when using one for the first time like I am there is a bit of a learning curve and a bit of experimenting is needed. Admittedly it's not rocket science but I do find that getting a steady decent pressure from a small coal fired boiler does require a bit of technique.

I'm about to start on a making a base in the next few days and part of that will be to raise the boiler slightly so that I can get air entering from the full 360o rather than just the front portion as it is now.






Offline nonort

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Re: Cleaning boiler tubes.
« Reply #23 on: January 10, 2018, 10:44:50 AM »
Have you tried fireing the boiler for an extended period using lumpwood charcoal. I ran simular boiler by using BBQ lighting fluid then changing over to dry lumpwood charcoal.By leaving the fire to burn out there seemed to be no ash to speak of and a few moments with an old vacuum was all that was needed for the clean up. Please take care with the carbom monoxide problems that could occur in confined spaces.

Offline Zephyrin

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Re: Cleaning boiler tubes.
« Reply #24 on: January 10, 2018, 06:34:16 PM »
Beautiful boiler, very nice piece of model engineering. for the tubes, I have got what you say...as regard the soot, you may try different type of coal, size etc, but yes you have to remove a lot of ashes and soot in the smokebox, and every 2 sessions is not that bad...

I had made a coal fired gauge 1 loco, copied from M. Evans' drawings "Southern Belle", a 221 (or 442) Atlantic, 1/32 scale, the time spent in maintaining her was huge, after each running session (mainly on a test bench), she had only 7 fire tubes and a larger tube for the superheater. I had to make at last 3 grids before the last one in solid stainless steel, the temperature of the fire was frightening for me in those days (A sissy as you said !!). I sold her as I really prefer building engine than running locos. 

Now I see at my club other modellers struggling with coal fired loco, from Aster or other, and all I can say is that the difficulty to maintain a stable fire comes from the inhomogeneity of the fire, usually glowing bright red in front of the door and darker deeper, in spite of mixing the coal regularly. This depends on the size and the form of the furnace, the grate etc, and would lead to a fire that vanishes at the first lack of attention.
With a loco boiler, starting the fire with an electric blower is mandatory, up to 2 bar, where the internal blower replaces the external one; at this point the pressure should continue to rise in spite of the blower steam jet, up to the running pressure 3-4 bar, when the exhaust from the running loco being sufficient for the draught. it takes about half a hour from starting the fire up to the loco running.

Now I have only meths internally fired locos, 5 min from lighting the fire to pulling trains...   


Offline Stuart

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Re: Cleaning boiler tubes.
« Reply #25 on: January 10, 2018, 06:42:22 PM »
As to coal

I used to run my 3 1/2 locos on Anthracite Grains
The 5 inch on Anthracite Beans

Itís smokeless and can be got at any good coal merchant

Ok it does leave a deposit in the tube but much less than steam coal ( you cannot get the real good stuff now a days itís to soft

Stuart
My aim is for a accurate part with a good finish

Online Gas_mantle

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Re: Cleaning boiler tubes.
« Reply #26 on: January 10, 2018, 08:05:13 PM »
Thanks guys,

I haven't tried it on lumpwood for extended periods, the problem I'm having is not that it doesn't steam well (on the contrary it steams well) but that I only get about 2 sessions before it needs a good clean out. I thought that doesn't seem long but it appears from what others say that it is the norm.

I'm hoping weather permitting I can try it tomorrow using an electric blower for the first time, that ought to mean I don't need to run it on wood till I get a decent head of steam and hopefully will reduce the soot build up.

It may be that when I have used up my present coal supply I'll try other grades to see what works best but the stuff I have now is meant for small steam locos upto 5" gauge.

I don't intend to raise pressure aggressively but here is a one off test I did to assess the steam blower efficiency - it goes from 20 - 90 psi in about 30 sec  :)

« Last Edit: January 10, 2018, 08:40:08 PM by Gas_mantle »

Offline tinkerer

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Re: Cleaning boiler tubes.
« Reply #27 on: January 16, 2018, 06:22:05 PM »
Well just sing the Mary Poppins chimney sweep song, & go to it LOL Chim chminy chim chim ceroo LOL Seems to me those are pretty small flue tubes? Maybe larger tubes would allow better flue gas flow & not accumulate so much ash & soot? Would the heat transfer area be that negatively effected?
You never know what you can do, till you try. Don't be afraid to try & fail. We learn more from our failures than our successes.

Online Gas_mantle

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Re: Cleaning boiler tubes.
« Reply #28 on: January 16, 2018, 11:42:28 PM »
The tubes do seem small but the boiler is to a recognised Tubal Cain design dating back to I think 1950s ? So it's fair to say they are appropriate to the style and size of the boiler.

I haven't worked out properly what the surface heating area is but it appears to be quite high with 51 tubes and a larger centre flue. Without measuring accurately it appears it can use water at about 1.25 gallon p/h when steaming hard.

Offline Jasonb

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Re: Cleaning boiler tubes.
« Reply #29 on: January 17, 2018, 07:22:29 AM »
What did TC originally design the boiler to run on? If designed to run off gas you usually use more smaller tubes as you don't need to worry as much about keeping them clean and having a good draft through the fire.

One other thing you mentioned the other day was that you are going to raise the bottom of the whole boiler, how will you control the much increased amount of air getting in as that will make a coal fire burn even faster?