need help building a wood fired vertical fire tube boiler

[steampower88]

Ok this is my first post and I live in Rochester ny. Ive been on smokstak for years and they suggested I come here because obviously a steam boat has a vertical boiler and compound engines. I'm looking to build a fire steam pumper at half scale. I'd like it to run it on steam and take it to musters. The setups aren't all that different between the two systems and any help would be awesome. Thanks everyone

[fredrosse]

A Vertical Firetube Boiler (VFT) can be had with water cooled furnace section, which is good for capturing furnace heat, but a more complicated build compared to the simple Stanley Steam Car type of boiler (not the later wire wound pressure vessel type, just a steel pipe for the outer shell), without an enclosed furnace. Either type has been built thousands of times, with good performance available for either one. What size (Shell diameter and height) would you be considering for your project, and what fuels would you consider?

[Lopez Mike]

Having built several VFT boilers over the years with all but one of them having water cooled furnace section ( Also called a water leg), I would assert that it isn't significantly harder to build this way. The key is to plan the sequence of operations. Figure out which welds to make first. It's just a collection of disks and rings and tubes with a couple of the disks full of holes. Hell for stout when together. Consult with your welder before cutting any metal. They are full of great advice.

I roll in the tubes and then do a sealing bead with TIG. By the time any tubes need replacing, it's time to heave the boiler. Unlike engines which can be maintained pretty much forever, I regard boilers as I do modern automobiles. I take care of them but they wear out and then I make another one. Radical view, I know.

Radiant heat is so very important compared to convective heat that to give up the area in the water leg is a big reduction in steaming capacity.

My limited knowledge of those steam pumping engines is confined to the observation that they were optimized for quick warm up from a spot fire to full output and minimal weight as they had to be rushed to a fire by two or three horses. Fueled with straw in at least some cases. I wonder how many fires they set on the way to an alarm?

Surely someone has a drawing. I might be wrong but I would be surprised of they lacked a water leg.

Will you have a couple of miniature horses to tow this beast? Wonderful project.

[artemis]

Many of these supposed VFT boilers that were built in the very late 1800s early 1900s were actually VWT (vertical water tube boilers). This was an answer to keeping the VFT (whether with or without a water leg) under fire and pressure while sitting in the fire house. The fire engine was positioned under a conical smoke hood so that the stack from the boiler was positioned directly under same. The stack exhausted directly through the room of the fire house. Used to keep the living quarters above cozy in the winter - never mind large city summer temperatures.

[fredrosse]

Looking at a full size steam fire engine at the Rough and Tumble Engineers Historical Association Old Threshermans Reunion (quite a mouthfull for a name!) last week, the construction is with a very large water leg, looks like about 40 inch diameter outer shell, and about 34 inch diameter furnace tube. Furnace about 40 inches high, with many many staybolts, probably a thin shell to save weight, the reason for so many staybolts. Tried to look inside the furnace, but too much heat and smoke to see well. My guess about 2 inch tubes, about 12 inches long, acting like horizontal water tubes, like an inside-out Porcupine boiler. From the look at how high the staybolts go on the outer shell, it would be almost impossible to have a conventional VFT arrangement, the water level would have to be almost at the very top of the boiler.

If I were to build a half size replica, the only thing I would need to change from direct scaling of dimensions would be to reduce the furnace diameter to have at least 2 inches between the furnace tube and the outer shell.

Anyone have a drawing of this type of boiler?

[Lopez Mike]

That design agrees with the proposition that radiant heat does more of the work. The flues are more to get the stink out. The historical trends in locomotive boilers show this. The firebox kept getting longer and the flues shorter. Of course they were grossly forcing the issue.

I've never seen staybolts between two concentric cylindrical tubes. Interesting tradeoffs between thinner wall thickness and the added weight of the staybolts.

[steampower88]

Thanks for the replies from everyone I'd like to make it 24" by 30" tall not including the fire box and wood fired for a fuel

[Lopez Mike]

That will be a fairly large boiler. That is the size of my VFT-30 measured on the outside of the insulation and lagging. I believe the outside of the shell is 18". I have 2" of fiberglass blanket and then the wood. I can work my 3 x 4 simple engine rather hard without forced draft. You are getting close to 5 h.p. You can look at the specifications on the Beckman Boat Works site.

You will be able to squirt a lot of water up in the air.

[steampower88]

That's the plan! The pump will have a 2 1/2" intake as long with a discharge. The discharge will have a 2 1/2 to two 1 1/2" males so you can run two hoses on one side. I figured it with a piston pump it displace 250 gpm with a double action dual piston pump. One more question how fast can you get a motor spinning on a normal firing of a boiler

[steampower88]

Having built several VFT boilers over the years with all but one of them having water cooled furnace section ( Also called a water leg), I would assert that it isn't significantly harder to build this way. The key is to plan the sequence of operations. Figure out which welds to make first. It's just a collection of disks and rings and tubes with a couple of the disks full of holes. Hell for stout when together. Consult with your welder before cutting any metal. They are full of great advice.

I roll in the tubes and then do a sealing bead with TIG. By the time any tubes need replacing, it's time to heave the boiler. Unlike engines which can be maintained pretty much forever, I regard boilers as I do modern automobiles. I take care of them but they wear out and then I make another one. Radical view, I know.

Radiant heat is so very important compared to convective heat that to give up the area in the water leg is a big reduction in steaming capacity.

My limited knowledge of those steam pumping engines is confined to the observation that they were optimized for quick warm up from a spot fire to full output and minimal weight as they had to be rushed to a fire by two or three horses. Fueled with straw in at least some cases. I wonder how many fires they set on the way to an alarm?

Surely someone has a drawing. I might be wrong but I would be surprised of they lacked a water leg.

Will you have a couple of miniature horses to tow this beast? Wonderful project.

Believe it or not they at times had a separate water keg that was constantly heated by wood or oil. They'd get a run, unhook the hoses after turning off the valves and run out with a pre warmed boiler at about 100° and finish heating it up on the way. There was also talk of them running out of wood and other fuels, people would bring out furniture to have them break up and feed the boiler. Lose just a chair and not your house. Many of the pumps had a water tank under the seat that would be full of water from the start. The boiler would consume the water, the engineer would just pump water in from that tank and then refill it with water from the pump. Running out of water wasn't the issue with these engines it was fuel. Just like a steam boat in a way lol. If you run out of water in a steam boat, I'd think you have bigger problems then that