Blowers / lighting the fire.

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Blowers / lighting the fire.

This topic has 18 replies, 10 voices, and was last updated 2 October 2019 at 22:41 by Nigel Graham 2.

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8 April 2010 at 21:11 #50530
mgj
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@mgj
Need some advice.

The Little Samson runs like a demon. You can pull it up to pressure from 25psi on the blower in no time. Few minutes

The problem is that first 25psi. As I say, once you get 25psi on the clock and open the steam blower valve she roars away.

I have a blower from Polly models which I’m running at 24volts. I light the fire with kindling soaked in paraffin, and anthracite grains, and then switch to the bigger beans, and it just takes an age to raise steam. Typically about 45-60 minutes with the damper fully open.

My feeling, since the fire burns so well is that either the electric blower or my lighting technique is at fault. It’s also quite a big boiler at about 570 bar litres. It holds about 5l of water.

Is that a reasonable time to raise steam, or do I need a blower with a bit more pull? And if so, what would be advised. The club does have mains power.

Flue tubes are all clean and brushed out
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8 April 2010 at 21:11 #2687
mgj
Participant
@mgj
9 April 2010 at 07:52 #50543
JasonB
Moderator
@jasonb
You don’t want to bring it up too fast as you want to allow all the metal to expand gently.

Try some charcoal before you go onto the anthracite.

Jason
9 April 2010 at 08:45 #50544
KWIL
Participant
@kwil
Do you really mean to say a 570 bar-litre boiler only holds 5L of water??
9 April 2010 at 09:04 #50545
JasonB
Moderator
@jasonb
Yes I think thats psi-litres not bar lts, or he’s running very high pressures

Jason
9 April 2010 at 12:02 #50548
mgj
Participant
@mgj
God I hate these metric units. PSI litres are so much better.

Service pressure is 125psig nominal, 143 psig permitted.(and it stays below that 140 on the safetys)

Understood about pulling up too rapidly, but is 1 hour plus reasonable for getting up to 25psi with fl of water. The loco boys seem to do it in half that time, but then as I indicated, its quite a big boiler by 5″ loco standards.

Funnily enough one of the lads at the club with a Sweet Pea takes a while to get up steam with the same blower fan, and again thats a fair sized boiler .

Smokebox is good and airtight.
9 April 2010 at 13:16 #50549
JasonB
Moderator
@jasonb
It does sound a bit of a long time to get just upto 25psi, I would have said 30-40mins and then another 20-30mins to get to full working pressure

Also the blower should be usable from 15-20psi so try using that a bit earlier.

Yours is the 3″ I think, do you have a steel or copper boiler? the steel will take longer for two reasons, firstly it does not conduct heat as well as copper and secondly the plates are thicker so there is less water space around the firebox.

Jason
9 April 2010 at 19:05 #50556
mgj
Participant
@mgj
Jason – thanks for that.

I have a steel boiler.

To agree and correct a poor impression – I don’t as a routine pull up from 25 to 125 at warp speed. I’ve done it once to test the blower and as part of a steam accumulation test on the safety valves. Normally once I have about 50 PSI on the gauge I shut the damper and turn down the blower out of thermal (mechanical) sympathy.

It actually steam very well – with the dampers closed just ticking over pumping water it will hold 100psi, and open the blower and you can hear the draught! Pulls me over the rather damp lawn with no trouble.

I’ve just brought one of the safeties down a bit lower in fact, because it steams so well. Its just getting all going ot start with.

I think I’ll try charcoal – parafin soaked kindling, and then add charcoal and try opening the blower valve a bit earlier. If that still causes a problem I think its off to the scrappies for a car radiator fan motor
9 April 2010 at 21:04 #50564
Chris
Participant
@chris16039
For what it’s worth, the members of my local club all use charcoal soaked in parafin to start their fires. This seems to rapidly lead to the need for coal and even the larger locos seem to be in steam very quickly. Is it possible that your kindling ashes are clogging the grate. This is just what is required for a wood burning stove where top draught is needed but not good for a fire requiring strong bottom draught.

Chris.
9 April 2010 at 21:49 #50569
mgj
Participant
@mgj
Thankyou sir. I’ll try that too. Got all weekend.

Still, it does go. Imagine having a problem that basic after 3 years work!
17 May 2010 at 22:23 #51776
the artfull-codger
Participant
@theartfull-codger
I find electric blowers are o-k for loco men & small[11’2 2″”] traction engines but I just use a chimney extension for my 4″ foster, no messing on with batteries etc & I face the ashpan into the wind if possible, I usually take about 3/4 to 1 hr to fully raise steam.
24 May 2010 at 10:42 #52074
Martin Johnson 1
Participant
@martinjohnson1
Just another couple of thoughts:

I would not normally expect to get steam on something like a Little Samson in much less than half an hour – as you say for thermal sympathy reasons. You will also need to time to clean and oil round.

How do you clean out the grate and ashpan? If these are clogged with last time’s rubbish you will never get a smart steamer.

Also, the tubes. Best cleaned out at the end of a run. During light up, the tar in the smoke condenses on the (relatively) cold tubes and sticks like poo to an army blanket.

Having said all that, I would be mighty suspicious of your electric blower. Mine uses an impeller from an old vaccuum cleaner driven by a 12 volt motor ex. car heater. The impeller is about 10 mm wide and 100 mm diameter, and it does not have any form of collector or volute. Once the fire is alight, I switch over to a 7foot extension chimney and generally get steam up in a little less than an hour on a 4″ scale Burrell.

Best wishes,

Martin
15 August 2019 at 18:36 #424355
Peter Wood 14
Participant
@peterwood14
We’re do I buy a little Samson, or possibly another it is for a Rob Roy.

peter
15 August 2019 at 18:42 #424358
JasonB
Moderator
@jasonb
I don't really know why your Rob Roy loco would need a Little Samson Traction engine?

Maybe better to start a new thread asking for what you actually need rather than drag up old ones.
15 August 2019 at 21:29 #424388
Nigel Graham 2
Participant
@nigelgraham2
I wonder if some of apparent tardiness is from using anthracite straight from the kindling.

Anthracite has the highest calorific values of the natural varieties of coal, but is not so easy to ignite and build up a fire as a more bituminous coal, and in some boilers at least needs a fairly good draught.

I know some engine-owners use a mixture of coals, but it might be worth trying a softer coal first to establish a good fire-bed, before using anthracite.
15 August 2019 at 21:45 #424391
duncan webster 1
Participant
@duncanwebster1
When a thread hasn't had a post for 9 years why don't the mods just close it?
16 August 2019 at 06:52 #424419
JasonB
Moderator
@jasonb
To give a new member a chance to post again if they are nervous about stating their own thread.
16 August 2019 at 08:24 #424432
Perko7
Participant
@perko7
I've read somewhere that a loco owner had problems with a fan blower for starting up, so fitted a compressed air connection in an inconspicuous location, plumbed into the steam blower with an isolating valve. He just hooks up an air compressor and lets the blower do it's job, seemed to work pretty well too. Once there's enough steam pressure he uncouples the air compressor and closes the valve then turns on the steam blower.
2 October 2019 at 22:41 #431544
Nigel Graham 2
Participant
@nigelgraham2
That method – air-supply to the steam blower – ought work well, and be relatively easy to arrange on a locomotive. And you don't end up with a blower-fan full of muck.

Some owners have used induced-draught arrangements in which the fan supplies air to a nozzle in a Venturi choke inside an extension chimney.

I have seen the compressed-air method used on a miniature traction, but it's not so easy to be discreet there! The particular engine was a freelance, of roughly 3"-4" scale overall size, and played fast-and-loose enough with prototypical practice for the extra little bit of pipe-work to be almost un-noticeable.

From what I've seen on the rally field, many owners of the larger-scale miniatures don't use a fan blower, but simply a high extension-chimney. This is slow but has the advantage of warming the boiler gently. On the other hand, looking at the typical smoke plumes, I wonder if it soots the tubes more than a stronger draught would, by not bringing enough extra air to burn the soot while its still above the fire.

++

The blower-in-extension way calls to mind an old book for children I saw in a second-hand shop window, some years ago now; apparently one of those compendia of boys' stories. It was the dust-jacket painting that had caught my attention. It showed a miniature locomotive being prepared on a raised-track steaming-bay, complete with electric fan and extension chimney; with an audience of two or three boys presumably of the book's target market demographic – as they say these days. The unknown artist had evidently understood the scene as he had depicted it very realistically – he may even have been a model-engineer himself, or perhaps lived next to a club track somewhere.
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