The Steamboating Forum

I am building a watertube boiler with a grate around 16 inches by 10. I am using a 5 inch dia funnel. What size of blower should i start with.
Also were should it be positioned? at the very base of the funnel or a couple of inches up?

Mike

Good question Mike, someone will know for sure. Locomotive practice would suggest, below the flue, and angle-adjusted so it emits into the middle of the lower end (just inside). Often a ring of pipe with very small holes.

Like you, I await the 'combined wisdom'.

Well, wisdom this is not, but I've found a ring of copper tube w/ end silver-brazed shut perhaps an inch below the beginning of the stack and small (#50 or so) holes pointing up works very well, and is quick and easy to fabricate.

- Bart

Mine is pretty crude. A .06 hole in a pipe plug about half way between the top of the tubes and the entrance to the stack. It isn't worth a toot when there is not much pressure as while getting up steam. But when racing about or recovering from inattention to the fire, it works great. I will be improving it. Probably after I read all of the posts here.

As I am wood fired, it is a great sight at night as the sparks fly and the passengers beat out the fires in their hair.

Lopez Mike wrote:Mine is pretty crude. A .06 hole in a pipe plug about half way between the top of the tubes and the entrance to the stack.

Sounds about like what we have.

Vertical fire tube boiler, with dome and flue leaving the top of this. Funnel above. Blower is a length of 1/4 bsp threaded pipe with a 90deg bend and a steel cap, inserted between the base of the flue and the top of the dome, cap has something like a 1mm hole in it.

That is all.

We are not talking highly developed blast rings for making best use of low pressure cylinder exhaust, we're talking about blowing the fire up a bit after we have stopped at a lock or for lunch. For raising steam in the bottom of a cutting, we have a pair of high power 'computer' style 120mm fans which are wedged into the ash pan door to give artificial draft when without steam. Most of the time natural draft is enough, certainly once there is heat in the boiler.


Daniel

I have ended up just taking the blower off the old boiler and fitting it to the new one. As the new boiler is way bigger than the old one I didn't think it would fit. However the pipe on the old one had to go up a very top steam take off when the new one is just a flat run. Annealed the pipe and straightened it out. The hole looks to be around 1.5 mm but not measured it.

It seems the collective wisdom says "suck it and see".

It'd probably still work well enough, with a hole, a whole lot smaller than that, and save a lot of steam. It only needs to entrain the air at the start of the stack, once it's moving its own inertia does the work, along with the rising heat and expanding steam.

Hi Mike

I seem to recall that SBMSL has one if not two articles on blowers if you want to look up the 'technical' side.

However, you can easily get away with very crude. I have just popped out to check what is on Frances Ann and see that the 1/4" blower pipe ends in absolutely nothing, yet it seemed to work pretty well in practice. I must do some reading and see about capping the pipe with something more 'technical'.

Happy New Year to everybody.

Pete


PS Have just found the Oregon Coastal Scenic Railway videos on YouTube plus their website. Fantastic scenery and steam. Wow!

I fitted a stack blower to Artemis to prevent "blowout" of the steam atomizing burner. I used a pressure reducer set to 19 psi to allow for a good flame modulation. I attached a 1/4" pipe to the regulated side of the regulator. This went into the stack ABOVE the damper (I burned wood to build up initial pressure) and was fitted with a right angle elbow. A brass plug, drilled with a 3/32" hole, tapered 7 deg from vertical. As soon as I started to show any pressure on my main steam gauge I opened the valve to the reducer and lit the steam atomizing burner. Immediately thereafter I opened the stack blower and once set it needed no further adjustment. Worked great and cost practically nothing. I used a brass "Y" filter and all brass pipe and fitting to get to the blower so that there were no particulates deposited from rusty pipe to clog the nozzle on the blower or the atomizing burner. Worked great. Zero maintenance.