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Post by Deleted on Jul 25, 2009 22:10:03 GMT
I was thumbing through my well thumbed collection of ME magazines and I encountered a fierce response in 1967 by a certain Mr Evans Ewins, discussing the merit or radiant superheaters and LBSC's resistance to them! Baggo's excellent post: Brazed S.S. Superheater,May 18, 2008, discussed the issue, but I would like to know what a radiant superheater looks like!
Thanks in anticipation
JB
PS: should I fit one to the Brit?
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Post by AndrewP on Jul 25, 2009 22:59:18 GMT
Didn't Doug Hewson write them up in the last year or so? I can't remember where though. Bent up from stainless tube and clamped into a complicated header in the smokebox, couldn't get my head round how that was drilled. I am sure he is offering them for sale - seen an ad this week.
Andy
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Post by baggo on Jul 26, 2009 0:16:48 GMT
Hi JB,
Radiant superheaters are the type that extend into the firebox, usually to the firebox back plate. They absorb heat directly from the fire ( hence radiant) and raise the steam to much higher temperatures than the 'normal' type that only extend the length of the superheater tubes. Although the radiant type can further increase the efficiency of the loco by decreasing the amount of coal and water used, they can also cause other problems such as with lubrication (more critical) and expansion of valves etc. This was the reason for the earlier seizure problems I had with Helen's piston valves and PTFE seals that turned to jelly!
You probably can't fit radiants to the Brit (not sure without looking at the drawings though) as the water tubes in the combustion chamber will prevent you extending the superheater elements past them.
John
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Post by Deleted on Jul 26, 2009 8:26:27 GMT
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Post by baggo on Jul 26, 2009 8:39:15 GMT
Whilst researching, I found this site which might interest the boffins out there....... The boiler shown was built by our club boiler inspector. Apparently he hydraulically tested it to 1000 psi with no ill effects  John |
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Tony K
Elder Statesman
Posts: 1,573
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Post by Tony K on Jul 26, 2009 8:40:18 GMT
Loco, they are fitted to most Simplex locos if built to drawings. No doubt someone at your club will reciprocate his for you so you can look up its anus to see!  Not sure if there is much upside, but one downside is if they fail, then they usually fail at the firebox end due to the extra heat - more so with copper ones.  |
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Post by Deleted on Jul 26, 2009 8:57:02 GMT
Baggo, if your boiler inspector is a 'he' then who is Susan Parker?
JB
PS. Or are you an odd lot up there just north of Watford?
PPS. Does the boiler work.......?
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Post by baggo on Jul 26, 2009 9:23:23 GMT
John (our boiler inspector) met Susan at one of the ME exhibitions and they obviously got talking about boilers so he got roped in to build one to her design to check it etc. I don't know if the boiler has done 'useful' work yet.
I don't know Susan personally but she seems a very clever lady. She designs electronic gear amongst other things but has an interest in model engineering as well.
Yes, we are an odd lot up here (especially at NWLSME ;D)
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Post by houstonceng on Jul 26, 2009 20:33:52 GMT
I do know Susan personally and she is, indeed, a very capable Engineer - both professionally and in her Model Engineering.
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abby
Statesman
Posts: 927
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Post by abby on Jul 29, 2009 11:19:55 GMT
I have followed Susan Parkers work for some time and find her web-site of great interest , I was pleased to find this link www.saunalahti.fi/~animato/3003/060af.htmlwhich gives some interesting facts on the wear abilities of certain materials used in the construction of the loco , but most gratified to see the method used for boiler hydraulic testing , as this was ridiculed by some members when suggested by myself some time ago. |
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abby
Statesman
Posts: 927
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Post by abby on Jul 29, 2009 14:00:16 GMT
Tony are you a misoginist ?almost every thread started goes somewhat of subject , this is evolution , if a new thread was started for every thought that enters one's head there would be millions , no doubt with few replies , in fact your comment is more "off topic" than mine, and adds nothing to the thread whatsoever.
In fact the question posed by this thread was answered very quickly , should it have then been closed ?
Quite right - more like DJ every day
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Post by Deleted on Jul 29, 2009 14:10:37 GMT
Well said Abby: as the originator of this thread I thought that the designer of that rather nice looking boiler deserved the accolades so freely given. After all, this is a friendly chat room, not a pontificatorium! Did I just invent a new word?
JB
Misogyny: 'An extreme dislike of females, frequently based upon unhappy experience or upbringing.'
A useful attribute if you want to spend many long hours in your workshop.......
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Post by metalworker on Jul 29, 2009 14:59:33 GMT
The only problem with the method of testing mentioned above is that it is easy to overdo things. The problem is that the heating has to be very gentle indeed because nothing appears to happen for a while and all of a sudden the accumulated heat works through and up rockets the pressure. It is easy to over-pressurise a boiler doing this. This is especially true of there is a small amount of air trapped which is impossible to avoid with some boiler designs.
I once left a centre flue marine boiler under hydraulic test overnight in the workshop to see if the pressure held. It did but the next morning the sun had warmed the workshop up and as a result the pressure had risen to about 3 times working pressure resulting in one scrap boiler because the ends had badly distorted.
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