Member postings for gary arthur

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

Yes indeed!

Cheers Jason.

Edited By gary.a.ayres on 18/03/2018 00:06:09

Edited By gary.a.ayres on 18/03/2018 00:07:12

You may very well be correct, Sir.

I'm generally not too shabby at coaxing a fire into life but that's no guarantee of success in this small-scale situation.

I hear you loud and clear and if as I experiment with possibilities it looks like it's going as you predict I will probably go down the gas route instead rather than install an electric blower. Nothing would be lost in that scenario as the firebox I have in mind would (I think) double as a burner housing with minimal modification.

Will certainly report on it in this thread when I get to that stage.

Cheers.

Edited By gary.a.ayres on 14/03/2018 23:23:54

Thanks for your input, Gas_mantle. I can see why coal would be difficult below a certain size - something about the difficulty of scaling nature comes to mind. If this project goes well I do intend to build a 6 inch boiler in the future, but the 3 inch is under way, so ...

... the firebox I have in mind will be quite wide at the bottom, roughly conical in shape and quite tall. It would be quite unusual in design but the aim is to make a functional device, not to make a model of anything in particular. I'm thinking the shape could generate a decent updraught, especially with a tall smoke stack on the chimney. I have been thinking about routing the exhaust up the chimney, However, instead of a blower I envisage the gentle use of a hand-cranked fan with outlets below grate level. That would blaze up the coal, but would also be very controllable.

The system would be idiosyncratic (fine by me!) but I think it could work so will probably give it a try.  It would also look very funky in an unusual way if I get it right. However, what I have taken from these discussions is a decision not to take any irrevocable steps or commit to anything until I have tried everything out with temporary setups. If the coal doesn't work, I'll use gas instead, and nothing lost but at least I will have tried!

Edited By gary.a.ayres on 14/03/2018 21:03:22

Thanks both.

@ Jason - yes, it does have just the one, you are right. I will think on...

The youtube clip ws intended more to convey the general feel than thedetails.

My thought has been to build something (out of two cast iron water pipe collars) that would enable me to try coal and other options before finally committing. Nothing would be cast in stone and would remain modifiable throughout. That of course would not fit with fizzy's advice to use an established design for a coal-fired boiler.

@ fizzy - you are definitely not teaching me to suck eggs! Or if you are it's because I don't know how to suck them in the first place.

Are you referring to a blower when you refer to return velocity, blast nozzle and venturi?

Ah ok - thanks for that Jason. Useful to know.

I doubt it too, and I suppose if the rules are somewhat vague that's something to be thankful for.

Putting together all of the suggestions people have kindly made on this thread, my only remaining questions at this point are:

(1) Whether to install a second check valve for water inlet (and I probably will, given I plan to try using coal), and

(2) Where the two check valves should be positioned in relation to each other (if indeed it matters).

Meanwhile, I am inspired by this as something broadly similar to where I hope I'm going with my project:

This is relevant (unless it has been superceded, but I have found no sign that it has):

http://www.nameng.org.uk/images/Boiler_Testing_Documents/2012_Test_Code_V12a.pdf

I still have to read it properly, but so far it doesn't seem to be too specific about the type and number of fittings used (apart from a safety valve). Will post more when I have read it more thoroughly.

@ Harry - I actually have the pump and two check valves already, so no harm in installing them I guess. Fizzy's idea of installing a bush and leaving it as 'spare' is a helpful one though.

@ Bazyle - Heh! ... you can only please some of the people some of the time...

Edited By Gary Ayres on 13/03/2018 18:26:36

Edited By Gary Ayres on 13/03/2018 18:26:57

Hi Brian -

Yes, I'm aware that it would need to be officially tested for public use. Didn't know about the insurance but no surprise there.

I may never take it outside of my own backyard, but am aiming to build it with enough 'future-proofing' to give me a chance of doing so if I decide to.

There is indeed a model engineering club local to me, and I was thinking that I should go and see them when it comes to testing, etc. Didn't know that the subs could cover testing and insurance! Worth thinking about...

I will indeed add to the thread as the project develops.

Thanks for your advice and encouragement.

gary

Thank you all.

@ Duncan - useful to know that I can plumb different sources to one connection - that supports what Jason said and it may be the way for me to go. I am pretty much following one of Stan Bray's designs (with a few tips from Myfordboy) but have upped the size to x 1.5. They don't say a lot about the positions of check valves, etc. though.

@ Bazyle @ fizzy - I am considering trying it with coal, small as it is. Small bits of coal! I have some nice cast iron bits and pieces to make a firebox with and the boiler will be attached to that. If the coal idea doesn't work out I'll swap it for another means of heating which I should be able to do without changing much on the firebox. I also want to hard install it all to a base, and plumb it with copper pipe. For these reasons I have bought a pump and check valves (and bronze bushes). I also feel I need a blowdown so I don't have to lift it around and tip it up. Maybe too elaborate for a first effort with a small boiler? Well, I'm not in a rush, and it will be good experience for if and when I decide to build a bigger one. We shall see how it goes...

I have the Harris book but can't find anything in it about the exact positioning of check valves etc., as per my question above. Maybe I'm just missing it - the lack of an index doesn't help!

Once again, thank you for your help.

Edited By Gary Ayres on 13/03/2018 13:39:29

Jason - thanks for the swift reply! Much appreciated.

The boiler is 3" diameter and 5" tall. Will it meet the regs with just one filling point?

gary