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Post by Roger on Apr 12, 2020 17:51:31 GMT
A quick sketch and it looks feasible I think you might run into trouble with the design as drawn because the weld is almost certainly going to melt the part of the plate that's outside of it, destroying the shoulder. I think you'd be better off putting the tubes up tight against each other, doing away with the shoulder, and make the diameter much larger while you weld it. A simple fixture could hold the tubes in the lathe so you could turn off the excess material of the flat plate, and then you can just weld on the outer piece. I wouldn't bother with a shoulder. |
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Post by gwr14xx on Apr 12, 2020 17:52:19 GMT
Andy/Chris,
I used that method on superheaters for a mate's Black 5, but I found it better to leave the plate oversize until the tubes were welded in (stops the edge melting away) - then trim to size and just butt weld the cap to it.
Regards,
Eddie.
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uuu
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Post by uuu on Apr 12, 2020 18:29:33 GMT
With four tubes, I'd vote for sending the steam down one pair, then the other. You'd get the double time in the firebox, but keep the flow speed/scour action/turbulence up.
I've not done any calculations, it's just a hunch.
Wilf
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Post by coniston on Apr 12, 2020 18:41:37 GMT
With four tubes, I'd vote for sending the steam down one pair, then the other. You'd get the double time in the firebox, but keep the flow speed/scour action/turbulence up. I've not done any calculations, it's just a hunch. Wilf Hi Wilf, like the idea, that would also reduce the number of connections to wet and dry header, I have loads of 1/4" 316 stainless tube so may have a look at using the smaller tube and 4 tubes per flue. The original steel boiler had 4 super heater flues with LBSC style 1/4" O/D copper non radiant super heaters, so having 2 pairs in each flue will add 50% to the steam flow path (roughly). Chris D |
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Post by steamer5 on Apr 13, 2020 0:23:04 GMT
Hi Guys,
Well never thought that the article would promote so many bright ideas! Well done !
Andy,
Love the drawing, makes the build nice & simple.
Just re-read the article & with the exception of the TIG welding , and assuming I read it right is what Bob has done, except he threaded the tubes & end cap & used the white stuff as he was trying to eliminate TIG welding. And as Andy pointed out why stop at only 2 tubes if you can get more into the flue......ok there is a limit you still have to get the flue gas down the flue & you don’t want to make it easy to block, which is a right pain to try & clear!
Wilfs comment re spear points, in this day & age why would you not put radiant superheaters in? Back in the day stainless was likely not as easy....read cheap...to get as it is now, let alone weld able in the home shop. Having had to replace a set of spear point copper superheaters that looked like they had been abraded out, the stainless one will outlast me & likely still be going strong for the next custodian of the loco....assuming he/she can get coal .
Well done guys, I think we may be advancing model loco design just a bit.....
Cheers Kerrin
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Post by steamer5 on Apr 13, 2020 0:50:14 GMT
Hi Guys, Just copied this from Doug Hewsons catalog... the-hewsons.webs.com/CAT16%202016_b.pdfSTAINLESS STEEL TUBE Superheater Elements 316 grade seamless tube, 5/32” X 24swg for superheater elements supplied ready bent with a double bend (so a 4m length tube becomes a 1m long superheater). Can be supplied from a 1m up to a 4m length tube. We recommend ‘HT5’ Flux and silver solder from CuP Alloys to solder these stainless steel superheaters Now run by.. steamworkshopstores.com/But I couldn’t find the superheaters! Cheers Kerrin |
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Post by springcrocus on Apr 13, 2020 7:46:00 GMT
I'm following this with great interest. The superheaters for Britannia are non-radiant copper, so likely to be somewhat ineffective. It would be nice to make something more useful i.e radiant-type and this would probably fit the bill. However, I will need a little help from the Pumphouse in the TIG welding department.
Sorry, Chris, drifting from the A3 somewhat.
Regards, Steve
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barlowworks
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Post by barlowworks on Apr 13, 2020 9:56:27 GMT
Sorry guys, I must put my hand up and show my ignorance. What is the difference in radiant and non radiant superheaters.
Mike
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Post by springcrocus on Apr 13, 2020 10:33:44 GMT
Sorry guys, I must put my hand up and show my ignorance. What is the difference in radiant and non radiant superheaters. Mike In my case, the superheater ends just about poke out of the tubes and, because of the combustion chamber, cannot be directy heated by the glow of the fire, only by the conducted heat of the burnt gases. With stainless superheaters, they can be made a bit longer and get direct heat from the glow of the fire. This could, in theory, add an extra hundred or two degrees centigrade to the temperature of the superheater tube ends. Copper would degrade very quickly at these higher temps.
Regards, Steve
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uuu
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Post by uuu on Apr 13, 2020 12:33:11 GMT
I think Jim Ewins got steam up to 954C with radiant superheaters!
Wilf
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Post by andyhigham on Apr 13, 2020 12:42:55 GMT
A friend of mine used to race tethered flash steam hydroplanes, he is a world record holder. There was so much superheat the steam inlet pipe to the engine used to glow red
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Post by coniston on Apr 13, 2020 19:41:14 GMT
Sorry guys, I must put my hand up and show my ignorance. What is the difference in radiant and non radiant superheaters. Mike In my case, the superheater ends just about poke out of the tubes and, because of the combustion chamber, cannot be directy heated by the glow of the fire, only by the conducted heat of the burnt gases. With stainless superheaters, they can be made a bit longer and get direct heat from the glow of the fire. This could, in theory, add an extra hundred or two degrees centigrade to the temperature of the superheater tube ends. Copper would degrade very quickly at these higher temps.
Regards, Steve
Yes, Steve has it about right, non radiant will stop short of the end of the flue so will only exchange heat with the combustion gasses passing down the flue. Radiant superheaters extend into the firebox usually as far as possible. They therefore get direct heating from the fire. Non radiant types usually become pretty ineffective as the flue tubes tend to block with ash which with the superheaters inside are almost impossible to clean, at least the radiant type still get direct heating even if the flues block. Chris D |
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Post by coniston on Apr 13, 2020 19:48:07 GMT
Hi Guys, Just copied this from Doug Hewsons catalog... the-hewsons.webs.com/CAT16%202016_b.pdfSTAINLESS STEEL TUBE Superheater Elements 316 grade seamless tube, 5/32” X 24swg for superheater elements supplied ready bent with a double bend (so a 4m length tube becomes a 1m long superheater). Can be supplied from a 1m up to a 4m length tube. We recommend ‘HT5’ Flux and silver solder from CuP Alloys to solder these stainless steel superheaters Now run by.. steamworkshopstores.com/But I couldn’t find the superheaters! Cheers Kerrin Hi Kerrin, well spotted, I remember these being in an article some years ago in ME magazine, I have today been experimenting with bending 1/4" stainless into a tight hairpin bend. I got as far as making a former and tried bending the pipe round after heating to red just to see if it was feasible. It looked like with a bending former on a handle to hold the shape of the tube it would work. So I carried on making the rest of what will be a simple bending tool. However disaster struck late this afternoon. After helping my wife move a bag of potting compost round the back and then re-grinding the HSS lathe form tool to improve the root radius in the bending former, I went to put it back in the chuck and hey presto it has disappeared. And I mean completely gone, I've searched the workshop, the house and garden and I just cant find it. Those bloody workshop gremlins have it somewhere, so I gave up and went indoors to read instead. Have to have another look tomorrow, probably there sitting in the middle of the bench tomorrow. Chris D |
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Post by andyhigham on Apr 13, 2020 19:56:57 GMT
It will be with all the 10mm sockets and 5mm allen keys
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Post by coniston on Apr 14, 2020 20:45:01 GMT
Well I found the missing part, would you believe sat on top of the compound slide on the lathe, god knows how I missed that yesterday. Anyway I finished the rather basic and rudimentary bending tool and tried a bit of 1/4" tube bending it cold. It worked better than I expected and wasn't too difficult to achieve the hairpin bend without significant distortion as you can see here with the bending tool.  Here's the HSS tool I ground free hand to form the bottom radius, first I plunged in with a parting tool to 1/8" depth and taking 3 bites at it to get 1/4" width. then I plunged in with the parting tool (2mm wide insert tip) in the centre to 1/4" depth before using the form tool to make the radius.  After a little squeeze in the vice as the tube relaxed a bit after bending it did fit into the flue.  So as an experiment I feel this is successful. Now I have to make my mind up which way to go forward making the super heaters. There are now at least three options, possibly four. 1. Twin 1/4" super heaters in each flue with hairpin bends. These will be joined with machined 'Y' pieces (2 x 1/4" into 1 x 5/16") before piping from wet header and to dry header. 2. One 5/16" super heater in each flue with latest design welded return bends 3. One 5/16" super heater in each flue with screwed ends and return bends 4. Twin 5/16" super heaters in each flue with latest design welded return bends Each has its pros and cons so some decision making necessary. I have to weigh up best performance against difficulty of manufacture and reliability in service. I like the hairpin 1/4" tubes purely from the fact there is no joint at the most stressed and difficult to access position inside the firebox. The single 5/16" ones could be best for access to clean the flues so keeping them working more efficiently during service. Welding is potentially more secure in the long term than screwed joints, but not so easy to make leak free in the first place although the latest design helps. Oh well time to think Chris D |
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Post by steamer5 on Apr 15, 2020 1:08:26 GMT
Hi Chris,
One of each & let us know how they work.....
Ok I go stand in the corner.........
Cheers Kerrin
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Post by Roger on Apr 15, 2020 8:16:10 GMT
Hi Chris,
I'm amazed there's room in that flue for a bend like that, you're fortunate to have that option. I think you're going to need something else to restrict the flow in that tube, the gasses are surely going to prefer that easier path rather than go through the other smaller more restricted tubes. Two hairpins, one longer than the other would allow two of those in the same tube, option 4, might be a good way to do that.
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Post by coniston on Apr 15, 2020 18:04:58 GMT
Hi Roger, yes it is fortunate that Don Young designed the boiler with 1 1/4" O/D super heater flues to take his favourite concentric tube designs. I am planning on having 2 super heaters in each flue so that should reduce the area for the gasses to flow. I just need to make a slightly smaller radius bending tool to get them in.
Interesting thought about the open flues though. I have a Super Simplex with three super heater flues but no super heaters at all, although I am planning at some stage to fit them. But the thing is it is one of the easiest locos to steam and rarely fails me. I regularly passenger haul at Southampton all afternoon with it. Even with the completely open flues I still get a significant amount of ash in the smoke box which I am sure would be coming through the lower fire tubes. I admit I do tend to fire up to the bottom of the door so that doesn't help. But there still must be a reasonable velocity of gasses through the tubes which shows as troughs in the ash, if you know what I mean. Also I run with a flat spark arrestor propped up behind the blast pip/petticoat pipe. After a passenger hauling run you can clearly see three whitish areas in front of the three flue tubes which indicates some high temperature gas flow, so your comment is correct, although it may be because the gasses drawn from the top of the firebox are just hotter anyway due to a more complete combustion in the bigger volume at the top.
Anyway tomorrow I hope to make the smaller bending tool and see if I can get two hairpins in each flue.
Chris D
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mbrown
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Post by mbrown on Apr 15, 2020 19:11:33 GMT
Sounds like your Super Simplex is well adapted to continuous passenger hauling at the expense of being an IMLEC contender. Horses for courses....
Have you tried tightening the bends in the stainless tubes without the former but at a brighter red heat? I found 1/4" stainless tube quite easy to bend freehand at medium red although I wasn't after hairpin bends - but it might still be capable of going a bit tighter without the cooling effect of the former, perhaps?
Good luck!
Malcolm
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Post by Deleted on Apr 15, 2020 19:55:14 GMT
I like what you're doing there Chris, I had been thinking of using Doug's super heater elements. My flues are also 1 1/4 inch OD and with Doug's elements at only 5/32 it shoild be possible to make up some nice multi-tubed super heaters. I'm still a long way from this though, gives me time to try and find a cheaper source of 5/32 stainless tube. My head tells me that I should be able to easily have four rows of tubes in each flue and still have room to clean then...a little R&D for the future...  Keep up the great work...she looks fab.. Pete |
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