Vertical Boiler Fittings

[gary arthurParticipant @garyarthur48070]

Yes indeed!

Cheers Jason.

[gary arthurParticipant @garyarthur48070]

Hi again –

Picking up on the other bit of Gas_mantle's suggestion, I have decided to install a steam blower on the boiler, and have ordered a 1/4 x 40 blower valve (the question of an electric blower vs alternatives remains moot for me at this stage – I'll cross that bridge later).

However, I have scoured the internet and found that information on how a steam blower is set up is surprisingly difficult to find. I understand the principle, i.e. a regulatable jet of steam up the chimney creates an updraught which draws the fire. At the other end, though, do I simply stick a bush for the blower valve into the boiler, near the top? In other words, is it in effect just a secondary steam outlet straight out of the boiler and into the bottom of the chimney?

I assume so, but would like to see it in black and white before I go making holes…

Edited By gary.a.ayres on 23/03/2018 15:00:55

[JasonBModerator @jasonb]

Yes it just takes steam and blows it through a small pipe usually with a reduced dia end into the chimney base. The reduced dia increases the steams velocity.

It also helps to run the exhaust steam into the bottom of the chimney to do the same job, this would have a larger blast nozzle so you don't strangle the exhaust gasses and is used when running, the blower is more often used once you get a bit of pressure in the boiler to help raise steam or to keep the fire going if you stop the engine mid way through a run.

This shows the larger blast nozzle and smaller blower pipe at the base of a traction engine chimney.

[BazyleParticipant @bazyle]

There is some science in blower nozzle positioning. The steam from a jet hole diverges (spreads out) at a known angle (you'll have to do some searching for that) and the idea is to get the steam plume to fit inside the bottom of the chimney and not overspill. Look into 'petticoat pipes' for locomotives.

Re extra clack. At some time you will make an engine with a built in or added water pump. Part of the fun of that is adjusting the size of pump and a thing called a bypass valve to get the flow of water in to match the rate of steam consumption coming out so the level stays level.

[gary arthurParticipant @garyarthur48070]

@ JasonB –

Excellent!

Yes, I had managed to ascertain that the blower pipe should be small, so I ordered a blower valve which is smaller than my main steam outlet will be. I'll find a way to further narrow the end of the pipe.

I was also thinking about taking the exhaust up the chimney, so great to have confirmation of that as well as your useful tip about keeping the blast nozzle wide so as not to strangle it.

Thank you once again Sir for your generous advice!

Edited By gary.a.ayres on 23/03/2018 15:31:24

Edited By gary.a.ayres on 23/03/2018 15:35:51

[gary arthurParticipant @garyarthur48070]

@ Bazyle –

Thanks on both counts.

I shall look into the blower nozzle dynamics as you suggest when I get to that stage.

As for the bypass valve info – very interesting. That is quite a bit down the line for me, but it sounds great and makes me want to explore…

[Gas_mantle.Participant @gas_mantle]

To narrow the blower pipe exit on my 3" dia boiler I just soldered a brass nipple over the end, I can't remember what size the hole is but is probably not much more than 1mm dia.

[gary arthurParticipant @garyarthur48070]

Aha… it did occur to me following JasonB's post above that a nipple soldered on the end might be a way of doing it.

I will keep this in mind, as well as investigating Bazyle's suggestion above.

Thanks, Gas_mantle.

Edited By gary.a.ayres on 23/03/2018 19:37:28

[JasonBModerator @jasonb]

I think I soldered a rivit into mine and then drilled out the rivit to the required size

[gary arthurParticipant @garyarthur48070]

Ah ok.

I can see that would allow some pretty precise control by choosing your drill size.

[gary arthurParticipant @garyarthur48070]

And indeed think I might be able to make out the rivet in your photo above.

[doubletopParticipant @doubletop]

Gary

I see references to Sandy Campbells 3" boiler. There are plenty of refernces to it if you Google and build logs on some of the other forums.

Drawings (but not the originals) here **LINK**

Pete

Edited By Doubletop on 24/03/2018 07:31:26

[gary arthurParticipant @garyarthur48070]

Wow! These are lovely drawings. JasonB also sent me some drawings of the SandyC boiler; these will make a nice addition.

Useful to know about the build logs too – will do a search for them.

My boiler in progress is actually based on a Stan Bray design, but this is all good info for my general understanding of such matters and for ideas to draw on even if not following the full plan.

Cheers Pete.

[gary arthurParticipant @garyarthur48070]

Hi again.

Thought it was time to post an update. The picture below shows the boiler in its present state, fitted with the test pressure gauge, Schrader valve for initial air testing and lots of blanking plugs. Not the neatest construction or silver soldering job in the world, but it's my first effort. It's a 1.5 scale (3 inch) version of Stan Bray's five-tube 2 inch design. The first air test was last night, to 10 psi. I discovered one very small leak where one of the fire tubes joins the top end plate (marked in the photo with a blue marker pen which you may be able to see).

I wanted to avoid having to torch it again if possible, and certainly didn't want to add soft solder to the equation. To my relief I was able to mechanically close the leak by further flaring the end of the tube with my pipe expanding tool. This evening the boiler held 15 psi of air for an hour, submerged in water with no leaks apparent. Hope it stays that way…

Next up is a water test to 90 psi (twice working pressure). Wish me luck…

 

 

Edited By gary.a.ayres on 13/06/2018 23:01:44

Edited By gary.a.ayres on 13/06/2018 23:03:33

[gary arthurParticipant @garyarthur48070]

Just for fun, I thought I'd post a picture of the boiler with all of its attachments loosely fitted on a temporary basis. The top plate and smoke stack (which will be of brass) have still to be added, as does the firebox. Not perfect by any means, but at least I can be happy tonight as it held air under pressure for the first time with no leaks.

The blower (top right) will be routed up the stack, as will the exhaust from the eventual engine(s). I may put a twist of copper down the central tube to help hold the heat where it belongs.

When it's all working the way it should I'll clean up the worst excesses of silver solder on the barrel and give the whole thing a polish to make it nice and shiny.

Edited By gary.a.ayres on 13/06/2018 22:57:06

Edited By gary.a.ayres on 13/06/2018 23:10:54

[Gas_mantle.Participant @gas_mantle]

Looks good Gary, I'll be interested to see how it performs

Where did you get the plans from ? I'd quite like to have a go making something similar.

[gary arthurParticipant @garyarthur48070]

Hi, and thanks for your encouragement.

I'm not too worried about turbocharged performance, but hope that it will at least run a small simple oscillator or two for a few minutes. That's still quite a bit down the road but I'm looking forward to moving on to engines in due course.

I got (and adapted) the plans and ideas from this book.

Cheers 

Edited By gary.a.ayres on 13/06/2018 23:30:35

[Gas_mantle.Participant @gas_mantle]

Thanks Gary, I have a piece of 3" dia copper tube that I plan to make a fairly simple boiler from but possibly a horizontal.

You should find yours will easily power a small wobbler for a quite a while between refills. I recently built a small entablature engine of about 1" bore x 1" stroke it is double acting but my existing 3" dia vertical boiler will run it at fairly high speed for 20mins and probably an hour just ticking over on a low gas.

I wasn't sure if you have added a clack valve to fill it in use but if not I'd advise it – mine is connected to a 3/8ths ram hand pump and that is fine for this size

[gary arthurParticipant @garyarthur48070]

Good to know – thanks!

A 1" bore engine for a boiler of this kind of size sounds pretty respectable to me.

Yes, I have made provision for two clacks as I'm hoping the boiler may pass a test at some point. I suppose that opens the door to the possibility of running an engine for quite long periods if one gets the balance right with heat, water and steam.

[Gas_mantle.Participant @gas_mantle]

Gary,

To give you an idea, this boiler is 3" dia with 9 fire tubes so it's probably not much bigger than yours but it comfortably runs my 1" bore engine.

At tickover speed it will probably run the engine for about 10mins with the gas turned off once the pressure is up

**LINK**

[gary arthurParticipant @garyarthur48070]

Hi again Gas_mantle.

I just clicked on the link and watched (and commented on) your Youtube video.

Very impressive engine, and the way it runs so powerfully and at a wide range of speeds from the 3 inch boiler is very encouraging, especially as it's not the smallest of engines.

Your 3 inch boiler has nine tubes; mine only has 5, but even still…

Very much looking forward to starting on my first engine when I get mine finished. I wonder if I might get away with a 1 inch bore cylinder when I do, especially as I'm not too worried about high performance as long as it runs…

Thanks for your helpful comments.

[Gas_mantle.Participant @gas_mantle]

Gary check your inbox – I sent a private message.

[gary arthurParticipant @garyarthur48070]

Thank you!

[gary arthurParticipant @garyarthur48070]

Edited By gary.a.ayres on 15/06/2018 18:36:16

[Gas_mantle.Participant @gas_mantle]

Looking good Gary, I'll be interested to see the finished item

You have spurred me on to have a go at something similar

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