|
|
Post by wdiannes on Feb 12, 2014 7:48:45 GMT
Perhaps you are right Julian; maybe I should carry on and complete the rest of it and see how she goes before making any radical decisions. I will undoubtedly find other things that I would have done different before I am done. A thin layer of lagging over the barrel would be a big help.
I have to say that I was happy with the return flue arrangement othewrwise. It drafted much better than I expected for not fitting a blower and the heat from the stack is about right and yet almost no heat is reflected back out of the main flue (at the burner) so the heat is being absorbed into the boiler. The barrel and the end plates, of course, stay at steam temperature and radiate heat into the air so at least lagging the barrel would be a big help.
|
|
|
|
Post by Deleted on Feb 12, 2014 23:12:00 GMT
Don't give up there, me hearty !!---------'Tis only a lull in the wind..... To para-phrase the world of newspapers}--- LAG and be dammed !!
|
|
|
|
Post by wdiannes on Mar 31, 2014 11:19:37 GMT
It has been ages since I added to this thread! The weather has been bitterly cold, too cold to heat the workshop, and the winter refuses to give up  but the patterns have been at the foundry for awhile and should (I hope!) be cast soon. I still have serious misgivings about the steam capacity of the boiler, I have material on hand to build another one, but in the available space (6" long, 4" diameter), I don't know how to get more evaporative capacity. Galloway tubes would help but then the boiler would have to be dismantled if they ever need repair. I have considered making it a water tube boiler, with the top 1/3 being steam/water space and the bottom being fire/tube space. But I have no clear idea on how to improve the evaporation. The only other boiler I have built is a16" diameter locomotive style in steel with 32" long flues. It was built by the rules of thumb in Harris's book and steam like all get-out. I guess I will just carry on with what I have and try to have something together for our club's 75th anniversary and small-scale meet in August. The weather has moderated enough to get back into the shop so I finished chasing some steam leaks in the plumbing of my 1-1/2 American and get it ready for steam and hydrostatic testing. Also got my 1-1/2 scale streetcar back in the shop. It is ready for some final priming and to be painted in advance of making, fitting, and installing 30-odd windows. I also need to build a riding car to pull behind the streetcar so it will be a busy spring but with the amount of snow we have here, there is a chance I will have something runable before the 4 foot snow drifts at the track melt!  I will post more when there is some progress. |
|
|
|
Post by GWR 101 on Mar 31, 2014 13:30:03 GMT
Hi, welcome back, looks like you have had our share of the snow and some ! Paul
|
|
|
|
Post by wdiannes on Apr 4, 2014 21:47:10 GMT
I got my castings from the foundry today and am EXTREMELY happy with the quality of the castings made from the 3D printed ABS parts - the detail is excellent! ![]()  I have also tracked down someone in Germany who built a 5" gauge model of this engine and purchased a set of his drawings. Although his drawings are Metric and in German, his model runs well so it is worth looking at. I am not totally happy with the steaming rate of my boiler so it may get redesigned. |
|
|
|
Post by Deleted on Apr 4, 2014 22:21:37 GMT
Hi DIANNE--------------hello and nice to see you back on the forum again !!...My, they do look good indeed....Did the ABS get totally destroyed then ??---------Are his boiler internals exactly to the same design as the original or has he increased the tube surface area somehow  ... I can't remember if you are using coal or gas for fuel but the latter might be worth considering maybe ??--------- How's your Winter doing... right now we've had a sort of mini dust pollution happening...Take care... |
|
|
|
Post by wdiannes on Apr 4, 2014 22:59:33 GMT
Yes, the ABS burned out cleanly - not a bit of ash or carbon on the castings and the investment process retained very fine detail from the patterns. Even the "layer lines" from the 3D print are visible in the iron. If/when I do it again, I will take more time getting a better finish on the printed parts.
In my boiler, I packed as much heating surface into the available space as possible (without totally displacing the water!). I fire with propane. I was going to add some Galloway tubes but didn't want to have to totally dismantle the boiler if the Galloway tubes ever need replacing. The German model DOES use Galloway tubes and steams better than mine. Neither of us followed the original design exactly - but then nobody knows if the original steamed well or not. I tend to use Harris' book "Model Boilers and Boilermaking" as my design bible and have found it to be an excellent reference source of model boiler design.
|
|
|
|
Post by Deleted on Apr 5, 2014 0:06:24 GMT
Ah ! --- our old friend "The Kayenne Pepper"....... Those "Curly" devotees on here can explain to the less fortunate what I'm banging on about..... This AMAZON price is "hopefull" I think >>>>>>>>>>>>>>>>>>>>>>>>> www.amazon.co.uk/Model-Boilers-Boilermaking-K-Harris/dp/085344109X ................ Actually, having just seen that cover photo then maybe a scotch boiler style would work ?? >>>>>>>>>>>>>>>>>>>>>>>>>>>  |
|
steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
|
Post by steam4ian on Apr 5, 2014 1:10:17 GMT
Dainne
One thing that will most likely improve steaming is a turbulator in each return flue.
A turbulator consists of a strip of stainless steel about the diameter of the flue twisted into a spiral; they increase the gas path and the turbulance causes a better heat transfer between the hot gas and the tube wall. Don't make them too pretty because irregular edges etc still the gas up more.
On small scale steam with gas firing they often have some sacrificial stainless steel mesh impinged on by the flame which glows red and gives radiant heat to the boiler surface to increase the heat transfer rate.
That old boiler would have relied a lot on the radiant heat from the fire and not the gas to tube transfer. On "modern" locos the fire box surface for radiant heat transfer was the most significant source of heat (about 70%) to the boiler.
Good to hear from you again.
Ian
|
|
|
|
Post by Deleted on Apr 5, 2014 1:18:39 GMT
A Turbulator ??----------- sounds like something BRAINS from "International Rescue" invented perhaps ??----- but no, it's a genuine article alright..Have a look at this ------------------ www.fuelefficiencyllc.com/turbulator.html ----------- Good call, IAN !! |
|
|
|
Post by wdiannes on Apr 5, 2014 10:49:35 GMT
Turbulators may indeed help. This is a Scotch marine boiler, having a larger combustion flue and 4 smaller return flues.
When I was testing the boiler I noticed a couple of good signs. First, there was very little heat radiating back past the burner into the atmosphere. Second, there a natural draft from the smoke stack; enough to provide positive air movement through the flues but not strong enough to be wasting a lot of heat up the stack so it seems the majority of the heat was being absorbed in the boiler.
I used a standard hardware-store propane torch burner for the testing but was not able to find one with a BTU rating so I do not know how much heat was available. Using a burner with a "lower velocity flame" might help and a turbulator especially in the combustion flue might liven it up.
I do not know what the German model uses for a burner but I am looking forward to finding out! In any event, I am inclined to go back to my first instinct and rebuild the boiler with Galloway tubes. I am not happy with the level of craftsmanship in my first attempt and know I can do better now that I have had some experience working with copper.
|
|
|
|
Post by Deleted on Apr 5, 2014 14:21:22 GMT
---------------- "I am not happy with the level of craftsmanship in my first attempt and know I can do better now that I have had some experience working with copper."............ And that's what it's all about in the end, I would say..Keep it going Dianne, we're all with you !!!
|
|
|
|
Post by wdiannes on Apr 26, 2014 23:26:50 GMT
Just before I left on a 2 week trip to visit family I got the castings from the foundry. They were done from 3D ABS prints by the investment process and came out RALLY nice! The gear teeth came out so well they will only require a little filing to be useable as-cast. Once I get over a nasty cold (picked up on my trip) I look forward to getting back to work on the loco. |
|
|
|
Post by Deleted on Apr 27, 2014 1:35:05 GMT
Hi DIANNE and good to see you back "on track" as it were...I bot a gold, doo !! ( Ahhh---chooooooooo !!) .. Loving those castings and thought this might be of related interest ??------ www.bbc.co.uk/news/blogs-news-from-elsewhere-27156775 --------- not long before we can 3D print an entire locomotive !! |
|
|
|
Post by doubletop on Apr 27, 2014 8:06:16 GMT
Turbulators may indeed help........... They are a spin off from the Turbo Entabulator that I believe Rockwell got involved in some years back.. Joking aside Turbulators came up in conversation at the club today. I'd never come across them before, then twice in the same day.... Pete |
|
|
|
Post by Deleted on Apr 27, 2014 13:01:26 GMT
What do you mean "Joking??"----------- this guy gave us several Tech-Talks at the MoD Engineering Depot here in Shropshire and, based entirely on his "Lateral Input", the whole of one years budget was placed ( and here's the clever part---- at £20 a time to avoid detection ) into the emerging futures market of "Toxic Primes" !!........... Which is why a Russian Mafia gangster now owns 2/3 of the MoD (Army) and I'm begging on the streets of London during the week !!-----------Spare a penny, Guvnor ??
|
|
but the patterns have been at the foundry for awhile and should (I hope!) be cast soon.
... I can't remember if you are using coal or gas for fuel but the latter might be worth considering maybe ??--------- How's your Winter doing... right now we've had a sort of mini dust pollution happening...Take care...