8" Steel Scotch Boiler

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Maryak

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I keep threatening to build a boiler. :p

Well I've started to design one.

It's an 8" Dia Scotch boiler in Steel with copper tubes and a dry back.

At this point I've left the firing options open to either a spirit, (blowlamp) or coal.

Scotch_boiler.jpg


Attached is an excel file covering the design parameters.

Best Regards
Bob

View attachment Boilercalc.xls
 
Do you have any particular plans for it's use or is it just for the challenge of building it? Either way I'll be following along with interest Bob.

Ray
 
Bob,
Thanks for posting the spread sheet. I see that you have used K.N. Harris for the estimated steam output.

Is this to be a scale African Queen?

Dan
 
Hi Bob

I have a particular interest in boilers of all types so I will be watching also.

Cheers

Rich
 
Herbie, Ray, Dan, Rich & Kvom,

Thanks for the interest guys. :bow: :bow: :bow: :bow: :bow:

Dan Rowe said:
Bob,
Thanks for posting the spread sheet. I see that you have used K.N. Harris for the estimated steam output.

Is this to be a scale African Queen?

Dan

No its actually to run my mill engine and I may add a couple of auxiliaries like a feed pump; and a fan if it ends up coal fired. Yes I did use quite a bit of Harris. I may have gone a bit over the top with the corrosion allowance but hey free 8" SD pipe is what I was given.

kvom said:
I'm guessing Bob has decided to convert his long-term hit&miss project to a steamer. ;D

I am almost at the assembly and see if it will run stage.......................but you may have a very valid point. :-\

Best Regards
Bob
 
I'm guessing Bob has decided to convert his long-term hit&miss project to a steamer. Grin

If not at least he'll be able to steam clean the beast!
 
Dan Rowe said:
Bob,
Thanks for posting the spread sheet. I see that you have used K.N. Harris for the estimated steam output.

Is this to be a scale African Queen?

Dan

I can assure you that Bob will not leave a screw driver in the safety valve that has to be kicked..... ;D

Dave

 
steamer said:
I can assure you that Bob will not leave a screw driver in the safety valve that has to be kicked..... ;D

Dave

True.................but I did once drop a chisel inside the rack and pinion of a 5" Parallel Slide Bulkhead valve. I could just get my arm down the inside of the case alongside the stem and with the aid of a water hose to keep the swelling down on my elbow and a mate to turn the hand wheel, it only took 4 hrs to get it out. :mad: :mad:

Next time I used a lanyard on the chisel. :D

Best Regards
Bob
 
Well that may be Bob....but you did get it out! :big:

Dave
 
Bob,
Nice design. You have a door for the front side of the tubes but what about the back side if they need to be replaced some time in the future?

Dan
 
Agree with Dan. Getting tubes out after 10 years is tough enough.
Though it looks like it's probably there already.

Dave
 
Dan Rowe said:
Bob,
Nice design. You have a door for the front side of the tubes but what about the back side if they need to be replaced some time in the future?

Dan

Thanks Dan and Dave, :bow:

Actually the front door was more for cleaning and aesthetics than anything else. You raise a very valid point.

I have been thinking about this for a while and the best solution I can come up with is to make both the front and back end plates removable by either fitting a ring or a series of brackets and screwing the plates to them - not forgetting heaps of STAG.

I won't amend the drawings until any other suggestions are evaluated.

Best Regards
Bob
 
Interesting mount to the sleepers.....hadn't seen that before, but it makes sense

What keeps the boiler from rocking side to side?

Dave

 
Looks great so far Bob :bow:

??? I cant see from your drawing how you're going to easily get to clean ash/crud out from below the grate if you're going to use solid fuel.

Kind regards, Arnold
 
arnoldb said:
Looks great so far Bob :bow:

??? I cant see from your drawing how you're going to easily get to clean ash/crud out from below the grate if you're going to use solid fuel.

Kind regards, Arnold

The damper door on the front gives access to the ash pit under the grate. A curved bottom rake and a slicer would be made to fit. At least this furnace is not corrugated like its' full sized cousin, where raking out is a right royal pita.

steamer said:
Interesting mount to the sleepers.....hadn't seen that before, but it makes sense

What keeps the boiler from rocking side to side?

Dave

tel, beat me to it. This is a copy of a full size marine installation. Believe me it ain't going anywhere, well and truly tested when some learner driver took out a 16" x 16" hardwood wharf upright at 8 knots. Mind you the concrete behind it stopped us fairly quickly. It also proved to be a great rust removal tool. The boiler room floor was ankle deep in the stuff. Lastly it was a fine opportunity to replace some 10' of rubbing strake.

Best Regards
Bob
 

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