By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th

Vertical Boiler Fittings

All Topics | Latest Posts

Search for:  in Thread Title in  
gary arthur13/06/2018 23:29:35
avatar
113 forum posts
351 photos

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 smiley

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

Gas_mantle.14/06/2018 21:50:47
avatar
359 forum posts
269 photos

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 arthur14/06/2018 23:05:50
avatar
113 forum posts
351 photos

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.14/06/2018 23:40:25
avatar
359 forum posts
269 photos

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 smiley

**LINK**

gary arthur15/06/2018 09:03:23
avatar
113 forum posts
351 photos

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.15/06/2018 18:18:55
avatar
359 forum posts
269 photos

Gary check your inbox - I sent a private message.

gary arthur15/06/2018 18:30:08
avatar
113 forum posts
351 photos

Thank you!

gary arthur15/06/2018 18:35:41
avatar
113 forum posts
351 photos

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

Gas_mantle.15/06/2018 18:40:53
avatar
359 forum posts
269 photos

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

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

gary arthur15/06/2018 18:48:13
avatar
113 forum posts
351 photos

Thanks Peter.

Now I'm anxious about the hydro test. Anxiety comes with the territory though...

Will post updates as it develops and will also be interested if you decide to start a thread on your build smiley

gary arthur22/06/2018 08:56:44
avatar
113 forum posts
351 photos

BTW apologies for the terrible sound quality on the above video. I bought a cheap new video camera. False economy. Back to the Samsung Galaxy Tab for the next one!

gary arthur25/06/2018 22:42:07
avatar
113 forum posts
351 photos

Hi again...

here it is all set up and ready for pressure testing with water... tomorrow!

All I did afer taking this photo was to silver solder on the pipe unions.

Tomorrow will either be a good day or a bad day for me...

gary arthur26/06/2018 15:36:35
avatar
113 forum posts
351 photos

Well.... not the outcome that I was hoping for today.

During the initial air test at 15 psi a couple of weeks ago it was apparent that there was a small leak where one of the fire tubes joins the end plate at the top of the boiler. I mechanically expanded the end of the tube which seemed at the time to do the trick as the boiler held 15 psi of air after that.

Today, however, under hydraulic testing to 90 psi that leak has come back to haunt me. I suppose that given this is my first effort I should be a bit pleased that there appear to be no other problems. However, this leak has to go. Further attempts to mechanically swage the tube end (without heat) have only made the leak worse, and it is now dropping from 90 to 45 psi in 30 seconds. I could fiddle about with it more but I'm afraid of stressing the end of the tube. The photos below show the problem - it's the tube at bottom right, marked in blue. You can probably see the stress marks inside the end of the tube but fortunately there doesn't seem to be any leakage on the inside, just round the outside where it joins the end plate.

My thought is to try to deal with it by caulking it with a ring of low temperature silver solder round the outside of the tube. I used medium temperature silver solder initially on that part of the boiler so my hope is that if I can do it this way I might be able to avoid disturbing other joins which seem to be ok at the moment. I'm also thinking of using my small portable oxy-mapp torch (instead of the big bad boy) to keep the heat as local as possible.

Does this seem like a reasonable plan under the circumstances? Or do any of you good people out there know of a better way for me to tackle it?

Photos:

Thanks...

gary

Edited By gary.a.ayres on 26/06/2018 15:49:43

julian atkins26/06/2018 22:07:18
avatar
1235 forum posts
353 photos

Hi Gary,

The proper repair would be to thoroughly clean and flux generously all over and re-silversolder the leaking tube. This is not difficult to do on a boiler like yours, though expanding the tube is with hindsight is not the correct procedure, and you will probably not get a penetrating joint, but you should aim to form a generous fillet. A loop of copper wire around the protruding end of the tube might assist in this.

Cheers,

Julian

gary arthur26/06/2018 22:40:44
avatar
113 forum posts
351 photos

Julian - thanks for this.

Now I'm wishing I hadn't expanded the tube, but as you say hopefully a fillet will do the trick instead.

I did wonder about adding some copper, and will think about the wire idea.

All the Best,

gary

duncan webster28/06/2018 21:03:48
avatar
2591 forum posts
34 photos

Gary, I've sent you a pm

gary arthur28/06/2018 21:06:43
avatar
113 forum posts
351 photos

Thanks Duncan - will look now.

gary arthur29/06/2018 02:03:48
avatar
113 forum posts
351 photos

Thanks to you Duncan and some others on another forum, the leak appears to be fixed yes.

Will post again when I move on to the next stage...

Cheers.

gary arthur10/07/2018 22:40:49
avatar
113 forum posts
351 photos

Hi -

Following an experience with a leaky check valve during my first hydraulic test, I followed advice and took two remedial steps: replacing the steel ball in the check valve with a nitrile one, and adding a globe valve between the pump and the check valve. This really did the trick, and the result was version 2 of my test rig which has no leaks in the water feed system. When that globe valve is closed, it's closed! Photo below.

 

And now the bad news: the improved system showed clearly that what I had thought was a repair was an improvement, but not a repair. The offending tube still leaks, albeit more slowly. During the test, the pressure dropped from 90 psi to 78 psi over a 30 minute period - better than it was, but a leak nonetheless. The photo below (top left tube) shows the problem - there is a gap under the fillet which I added, probably due - I think - to insufficient heat during the attempted repair. My plan is to reheat it and try to melt the solder which is already in place so that it will flow around and into the joint more than it has. The boiler is now back in some new pickle for 24 hours to get it as clean as I can prior to reheating it, hopefully tomorrow evening. I will, of course, use plenty of flux and follow the previous advice on giving the whole thing an overall background heat with propane before focusing on the flaw with oxy/mapp.

However, if anyone has any other ideas I'd be happy to hear them.

Photo below:

gary

Edited By gary.a.ayres on 10/07/2018 22:43:26

JasonB11/07/2018 06:53:46
avatar
Moderator
18118 forum posts
1996 photos
1 articles

Yep lack of heat in the tubeplate, you have only got the end of the tube upto heat.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
ChesterUK
Warco
cowells
Allendale Electronics
emcomachinetools
Eccentric July 5 2018
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest