spark arrestors

[steamjohn248]

In other words oily sooty specks on the passengers clothes arrestors.

We all know what the archtypical Yankee Loco spark arrestor chimneys on their early wood burners looled like from the outside (in my case from the Saturday morning pictures in the 50s) but since they must have worked, might they be worth looking at on a model loco.

Does anyone know what the gubbins INSIDE consisted of?

I've had experience of the spark arrestors currently fitted to Main Line locos after the spate of lineside fires a year or so ago but they are of course screens fitted inside the smoke box and if you scaled down the mesh size the thing would choke up in no time.
(even the full size ones can mess up the steaming of an engine if the coal is really dirty), so I dont think they are the answer.

Any ideas anyone?

Cheers

Steamjohn

[Uzzy]

Steamjohn
I put spark arrestors into google and came up with the following a chap called Thomas Qinlivan patented a spark arrestor in 1909 he live in Australia maybe Tel could see if he can find anything else out form the pataent office?

[chameleonrob]

I built a balloon stack for a friends loco a while back, the internal gubbins are shown on the sketch, the top parallel part is a gauze cylinder that can be easily removed. I allowed the cross sectional area of the smoke path to get bigger with every turn with the result that there is little resistance to gas flow but the exhaust is much slower, allowing entrained particles to drop out. oh and the loco blew smoke rings something chronic after it was finished.

img.photobucket.com/albums/v700/chameleonrob/Image2.jpg

rob

[lancelot]

Hi Steamjohn,
Could not find any results re ''Quinlivan'' 1909 in the European data base, but found this instead, might be useful.

v3.espacenet.com/textdraw?DB=EPODOC&IDX=GB189730731&F=0&QPN=GB189730731

Inventor was...Rufus William [Aust.] 1898/09/10
All the best,
John.

[steamjohn248]

Thanks Guys for the response.

Rob

I take it that the gasses pass up the divergent cone, same size at bottom as chimney which as you say will slow them down, they then hit the downward pointing cone below the gauze cylinder, particles are thrown outward, lose velocity and end up at the bottom of the baloon while the (hopefully ) clean gases pass to outside throught the gauze.

I had thought of a rotor driven by the upward draught acting like a certrifuge and thowing the muck sideways. (Bit like the oil separator in the exhaust steam line to an exhaust injector on the big railway) but your way sounds a lot less complicated.

We'll gie it a go.

Thanks again

John

[chameleonrob]

you've got the idea, the divergent cone in this case was the old chimney which the spark arrestor fitted over. the guy I made it for had the steam oil turned up way too high with the result that him, the engine and the passengers were black. all that stopped when the spark arrestor was fitted, although cleaning the tar like substance out of the bottom of the balloon was hard.

rob