Supporting > Boilers
A WATERTUBE BOILER FOR MY TRIPLE EXPANSION ENGINE
steamer:
That looks like a great start!!
A bit of operational advice, with small watertube boilers
Keep your feedwater VERY clean.
And a engine driven feed pump that will keep up with the demands of constant feed.
Small water tube boilers are VERY touchy....and can be tough to control, and a engine driven pump that pumps a little all the time I have found to work the best.
Additionally, if you can fit a feed water injector it would awesome! it is wonderful for those times where you have more steam than you need and rather not lift the safety. Fire off the injector and that works great as a calming a raging water tube boiler down long enough to close the dampers or turn the fuel feed down.
.....ask me how I know this..... :cheers:
Dave
crueby:
Dave, side question on the injector idea - I've seen them used on full size engines and down to ride-behind sized locomotives - how small can they be made and still work? Is there a physics limit?
steamer:
--- Quote from: crueby on January 21, 2024, 06:44:05 PM ---Dave, side question on the injector idea - I've seen them used on full size engines and down to ride-behind sized locomotives - how small can they be made and still work? Is there a physics limit?
--- End quote ---
I have a Superscale Locomotive works economy injector for the boat, which is fine up to 13.5 square feet of heating surface and 160 psig. It's a small injector and It has a capacity, IIRC, of 33 oz a min, and fits in the palm in my hand. That said I've seen much smaller 3/4 scale ( 3 1/2 gage or Kim's switcher size) sold in the UK fairly readily. That's probably the limit on how small they can get. I'm not sure how small this boiler is, but it might be big enough for it. Getting the combining cones machined accurately enough and small enough is probably the limiting factor here
Water circulation on a very small watertube boiler is violent, and they really want a constant water level, if possible.
Sabino has a water tube boiler with 960 square feet of heating surface 55 gallons of water, and 64 square feet of grate area, and will lift the safety in 17 minutes from striking the match...but, with that responsiveness, comes sensitivity to draft and water level.
Dave
uuu:
Commercial injectors in the UK can work, but there are plenty of unreliable ones out there. The trick is to make your own. The book to get, which goes into all the necessary procedures is by D A G Brown. (Simplyloco - you'll know this already)
Nothing will be beyond a person of your skills. You can go really small - although it gets more tricky as you go smaller. 11oz and smaller are the devil's work. Here's an account of someone doing a 4oz/min one!
https://www.modeng.johnbaguley.info/injectors/injectors1.htm
Wilf
simplyloco:
Wilf is quite correct, there are small injectors out there that can be made to work. I also have the DAG Brown book. I have known John Baguley since 2005: he got me into this!!!!
However, has anyone noticed that this boiler will be fed by the twin cylinder positive displacement Edwards pump on the Bolton Triple? I have every confidence in it, and the associated bypass valve... :LittleAngel:
Luv
JB
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