Averill water tubes - Bat

Spend a day or two on this and there doesn't seem to be much about and to my newbie eye it simply makes no sense

And in 80 years nobody seems to have taken a picture of their work

If the tube runs from halfway along the boiler to beneath the footplate or firebox then is it plugged at the cab end?(must be, right!)

Looking at the drawing I would say no, it is not plugged. Water must flow through it

Roy

The tube is open at both ends, water flows through it.

The tubes are open. The heat sets up a siphon effect as steam is made, lost up the short leg and replenished with water down the long leg.

Just love LBSC's grasp of heat loss and radiation theory, though.

Martin

OMG I've just figured it out

He's describing 2 totally different boilers

The second one is a system I've not been aware of, the tubes dip into the fire and the boiler sits over the firebox...?

So the flue runs under the boiler

Edited By Ady1 on 18/02/2023 14:01:02

Yep you got it ! Other bit you circled in red is possibly safety valve and steam outlet.

duh

I've just spent the last 2 days trying to shoehorn those tubes into my loco boiler, I thought they were to increase the heat transfer surface area

There aint much out there on these things, I'm number one on google after 1 day

Edited By Ady1 on 18/02/2023 14:33:47

The simpler boiler with the thermic siphons was common practice for methylated-spirit (or nowadays perhaps) gas firing, not coal.

You are right in the tubes increasing the heating area.