Spark arrester

Anyone with any thoughts as to a suitable size and material mesh to fit above the chimney on a steam loco?

 

Were spark arresters fitted above the chimney? I would have thought that would have been too restrictive on the steam and fire gases being exhausted by the blastpipe arrangements. I am aware that they used to have screens in the smokebox to catch ash etc.

 

Some were fitted, several panniers were fitted like that based at Didcot for working in the ordnance depot, if you see one you will know it!

 

Perhaps I should have added that it is for a Sentinel Loco, and it doesn't have a smokebox as such.

 

I have taken advice by the fire brigade as to what size embers/sparks would be a problem during dry spells and was told if anything hits the ground bigger than 1.5mm dia in dry weather it would cause a fire. Needless to say my sentinel was fitted was a chimney top fitted spark arrestor of 1.5mm mesh, the secret of not creating draughing problems is to make the spark arrestor much bigger than the chimney top so the exhaust can breathe.

Stan

 

I'm in 'don't know' country at the moment on this subject for our application. How long before a 1.5 mm mesh gets bunged up solid? Or melts, even? On the face of it one might as well weld a piece of steel plate on the funnel top. Got some 3mm mesh to hand so am going to try with that first. The thinking is to make a 3" deep sided upturned box about 10" x 15", to be an inch or so above the top of the funnel and attached on the opposite side of the 'swing round' funnel damper.

 

Would two 3mm mesh's a few inches apart work?

Just a suggestion, I'm not an engineer or physicist, feel free to shoot me down in flames.

 

Ralph, this sounds rather like what was known in Sentinel terminology as the "Beehive" type as used on waggons from 1931 onwards on chain drive ones. We have a plain rimmed funnel on the loco, so a separate device is necessary. I've had another look at the mesh and it seems to be more like 2 mm than 3 mm, so we'll try that. Just hope it doesn't melt!

Nice to see that you have spelt waggon correctly in connection with Sentinel.........apart from my computer automatically deleting the second 'g' which means that I have to go back and re-insert it!

 

Bit puzzled there Eightpot.

Ralph describes a device which sits inside the chimney flue, whereas I'd think the 'beehive' type sounds more like the wire cowl that fits on top of the chimney? So why won't the internal baffle fit you machine? Whether or not it will knock out embers >1.5mm I would be doubtful.

 

Ralph, your sketch looks like the arrangement on the later "S" type shaft-drive waggons, the funnel base of which is different to the earlier chain-drive ones.

 

I'm feeling benevolent today, Ralph, you can stand up now.

 

Never imagined that this topic would get back to Bavarian Serving Wenches..............

 

Have you made a spark arrester for you sentinel yet? Cos I MADE one for William at elsecar heritage railway.

 

Why should it melt? If you make an external mesh ball as is fitted on a loco on the Mid-Suffolk, it will be in a constant flow of cold air when the loco is working - and it can't be as hot as the inside of the smokebox, which doesn't get hot enough to melt.