Wet exhaust coal firing

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AFGadd
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Re: Wet exhaust coal firing

Post by AFGadd » Mon Jan 29, 2018 10:43 pm

Having seen the length of the steam line from the lubricator to the steam chest, I'm not surprised that you're getting a "wet front end"...

I will be amazed if that doesn't make some difference, TBH?

Keep us in the loop, please.
Last edited by AFGadd on Mon Jan 29, 2018 10:45 pm, edited 2 times in total.
Andrew

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Re: Wet exhaust coal firing

Post by dewintondave » Wed Jan 31, 2018 9:29 am

Hi Tom,

That's a long loop of tubing before the lubricator, I'm inclined to think it's unnecessary
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Re: Wet exhaust coal firing

Post by tom_tom_go » Wed Jan 31, 2018 10:29 am

dewintondave wrote: Wed Jan 31, 2018 9:29 am Hi Tom,

That's a long loop of tubing before the lubricator, I'm inclined to think it's unnecessary
I see your point mate but the reason it's like that is to allow for the whistle pipe work which I am going to redo and will possibly lag as well?

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Re: Wet exhaust coal firing

Post by tom_tom_go » Sat Feb 17, 2018 8:06 pm

Ready for testing:

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The whistle pipe has been replaced with a new one so it does not show in the cab front window. The pipe lagging for the whistle is purely for show as it's much thinner than the steam pipe lagging you see in the pictures.

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Re: Wet exhaust coal firing

Post by LNR » Sun Feb 18, 2018 6:28 am

That looks well done Tom, like the black. I imagine there's a yard or two of cord in that lot.
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Re: Wet exhaust coal firing

Post by AFGadd » Sun Feb 18, 2018 5:57 pm

Looks good, and it can't possibly do any harm and will probably have a positive effect?
And either way, it looks great.
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Re: Wet exhaust coal firing

Post by GTB » Mon Feb 19, 2018 8:48 am

tom_tom_go wrote: Sat Feb 17, 2018 8:06 pm The whistle pipe has been replaced with a new one so it does not show in the cab front window. The pipe lagging for the whistle is purely for show as it's much thinner than the steam pipe lagging you see in the pictures.
Neatly done. The black lagging makes the pipework less obtrusive, but I'm not sure how long the cab floor on a coal fired loco will stay that colour...........

For what it's worth.......

I was running the Hunslet yesterday on the rolling road and did some measurements while I was at it. This loco is my usual lab rat and is a standard 45mm gauge Roundhouse Bertie with different bodywork. Fairly typical of most Roundhouse locos I imagine.

Even though it is 'superheated' it produces about 10ml of condensate as the cylinders warm up and then produces another 5ml or so of condensate over the rest of a 30min run, plus maybe 0.5ml of steam oil. When the smokebox door is opened drops of water can be seen regularly dripping off the base of the chimney and running down the exhaust pipes when running.

The cylinders are up to temperature within less than a minute of moving off under steam and when steam is shut off, the cylinder temp drops about 1degC every 10sec for the first minute or so. No extra drops of water were seen when the loco was stopped, reversed and started up again, say a 10 sec stop all up.

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Re: Wet exhaust coal firing

Post by tom_tom_go » Tue Feb 20, 2018 9:29 pm

Hopefully, these chaps will dirty the floor up soon:

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Re: Wet exhaust coal firing

Post by LNR » Wed Feb 21, 2018 1:34 am

Didn't your fireman like those bits of coal, thought he'd heave em out the back! :lol:
Grant.
PS it's hard when you have to get non scale things like a coal shovel, into a scale cab!

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Re: Wet exhaust coal firing

Post by tom_tom_go » Sat Mar 10, 2018 9:14 am

LNR wrote: Wed Feb 21, 2018 1:34 am Didn't your fireman like those bits of coal, thought he'd heave em out the back! :lol:
Grant.
The size of the coal pieces would not last five minutes in her fire!

I don't like the shovel so might change it for a Locoworks brass one I have which has been chemically blackened.

Maybe if I fit a tender he would be digging the right way :mrgreen:

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Re: Wet exhaust coal firing

Post by Peter Butler » Sat Mar 10, 2018 10:38 am

Regardless of the size of coal or shovel Tom at least you have figures in your locomotive whereas so many live steamers are runaways with no driver!
The best things in life are free.... so why am I doing this?

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Re: Wet exhaust coal firing

Post by 11thHour » Fri Mar 16, 2018 1:45 am

I attach a drawing of a theoretical solution to Wet Exhaust.
I have done no experimentation on my theory, and have no qualification whatsoever in the field.
Per the drawing, the cylinder exhausts are joined at the lowest point by a T junction. the bottom of the leg of the T is blind but for a very small hole. (how small to be determined by experimentation) The theory is that the condensed water will accumulate at the lowest point of the T and be expelled by exhaust steam pressure. The hole must not be large enough to let excessive steam out.
WetFunnel.jpg
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An alternative would be to put a leg on each exhaust and not connect them.
Perhaps someone has tried this before? did it work?

Tim

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Re: Wet exhaust coal firing

Post by tom_tom_go » Fri Mar 16, 2018 11:59 am

Hi Tim,

I had a similar idea but this will impact the exhaust draft.

The hole needs to be temporary to clear the condensate so you would need a servo or lever to open and close it.

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Re: Wet exhaust coal firing

Post by 11thHour » Sat Mar 17, 2018 9:36 pm

I was hoping to find a hole size which would not expel much steam but at the same time pressure the water that has condensed at the bottom of the tube. Maybe the water tension would prevent the water expelling through such a small hole?

Tim

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Re: Wet exhaust coal firing

Post by tom_tom_go » Sun Jun 03, 2018 4:09 pm

I am such an idiot.

You know that feeling when you re-read instructions and then the penny drops, well I did that this weekend and realised the replacement nozzles that are supplied by Riverdale for slow running I was fitting on the blower and not the exhaust! The blower nozzle has a tiny hole compared to the exhaust type and this nozzle has been sitting in my spares box for ages while I have been mucking about with exhaust nozzles for both blower and exhaust.

So now that is sorted the amount of condensate has reduced significantly.

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Re: Wet exhaust coal firing

Post by pandsrowe » Mon Jun 04, 2018 8:09 am

I think that's very brave of you to admit to.
Fortunately on this forum where we are all such gentlemen, you won't come in to too much ridicule :D
Phil

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Re: Wet exhaust coal firing

Post by tom_tom_go » Mon Jun 04, 2018 8:17 am

No I am an idiot Phil!

The funny thing is when I first built the loco I would of had the blower nozzle on right as the instructions are clear it's just through my swapping about of nozzles I then got it all wrong.

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