thinking caps on ?

[Russ Bellinis]

Water tubes in the firebox. Steam engines make steam quicker by running the water through tubes in the middle of the firebox rather than putting a big tank above the fire and trying to bring it to a boil.

[doctorwayne]

I think that thermic siphons is the correct name - basically water-filled tubes which pass through the firebox. Not to be confused with a water-tube boiler, though.

Wayne

[jim currie]

Doc wins they are Nicholson thermic syphon's use to circulate the water in the boiler so the water stays at a even temperature in the boiler thus increasing efficiency.gives a prospective on the size of the last of steam don't it .

Jim

[MountainMan]

I'm going to need a hint.....

Is it Animal, Vegetable or Mikado??????

the hint is where is this post located.

Riiiiight...he's welding an "upper berth"! I sleep in one just like it! 8-)

[Sumpter250]

I think that thermic siphons is the correct name

That'll learn me to be two days late and twenty bucks short!

I knew what the were, but that raises the question......and I don't have any reference material that mentions....when did syphons first come into use in steam locomotives? I am going to assume it was sometime around the advent of "superpower", and superheated steam. One of the benefits of thermic syphons, was the flow of recirculated water, would keep water over the crown sheet for a short time after the water level in the boiler dropped below the crown sheet. A safety feature, but definitely not an excuse for letting water level drop too far.

[Sumpter250]

Is it this thing?

This is a great shot of the inside of a boiler.....without, tubes, flues, and flue sheets!
You can see the firebox with its staybolts,the inside of the backhead with the firebox door opening. This loco does not look like it has thermic syphons, as they are part of the crownsheet, and connect to the rear fluesheet (front of the firebox), just above the mudring.

[Will_Annand]

No, it is a flux capacitor for the new Delorean Railcar.

[Sumpter250]

.he's welding an "upper berth"! I sleep in one just like it!

I always slept in the top rack (upper berth), because I didn't get seasick!!, and.....gravity....nuff said.