Model Engine Maker
Engines => Your Own Design => Topic started by: gary.a.ayres on September 09, 2019, 10:37:18 PM
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Hi.
With my 3 inch boiler and 12 mm oscillator now finished, the next step is to incorporate them into a properly finished little steam plant. The boiler is loosely based on a design by Stan Bray, and the engine on a design by Steve's Workshop, but I have taken plenty of liberties with both.
Here are all the components of the plant that I currently have:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/838589.jpg)
Three interchangeable burners (pressurized kerosene, pressurized alcohol, gas), hand pump for boiler feed, boiler stand, engine and boiler.
My plan is to bring together all of the components of the plant and experiment with layout before looking for a base board, so that I get the size of the board right.
In addition to the above, I will need a water reservoir (currently in progress) and I'm also considering a steam separator for the exhaust (perhaps combined with a feedwater pre-heater, and possibly route the exhaust up the boiler chimney), an inline lubricator of some kind for the engine, and maybe even a very small generator and lamp post.
However, I don't want to go over the top, so I'd welcome your feedback on whether you think that's excessive for a plant this size. Equally, if you have any suggestions for anything else that I might add in that isn't mentioned above, please feel free to say so, as it's all part of the fun. :cartwheel:
Cheers,
gary
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Hello Gary,
Fantastic job that you have done with this entire project and some beautiful machine work on the parts.
Have a great day,
Thomas
PS, enjoyed your last video
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Thanks Thomas - very kind of you.
All the Best,
gary
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Hi Gary, definitely not over the top. I believe in always including a lubricator, a displacement type for steam, and an exhaust separator to keep the bench cleaner and dry. And the generator and light will be a great and appropriate conclusion. I have completed three plants like this, only one with a purchased boiler.
I have yet to build a feed pump. I would like to say it is on the list, but definitely a “one day”.
It’s looking great so far. Your artistic input shows in all your items and I look forward to seeing the progress on the complete plant.
MJM460
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Thank you MJM!
I'm pleased you think my scheme is reasonable.
I have a feeling that I'll probably be looking for some advice from you (and others) along the way. :)
gary
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I'm thinking of incorporating a combined steam separator and feedwater preheater into the plant.
I'm sure that I saw some plans for one somewhere online once upon a time, but a search isn't bringing much up.
Keith Appleton has a short youtube series about building one, but I have a feeling it could be done more simply and cheaply than his (nice as it is with its cast end caps). I'd also prefer an upright one (his is horizontal).
Does anyone know of any plans for one? If not, I suppose I could just scratch build it using KA's as a guideline...
As with many things, the principle is simple enough but the devil is in the detail.
Thanks.
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Hi Gary, so long as you do not put a valve or other stopper in the stack or chimney the separator is always open to atmosphere and not a pressure vessel, so does not have to be designed for pressure. You only have to design for function, along with your artistic input.
I have made them vertical with success. The idea is that the engine exhaust enters high in the cylindrical side, preferably tangentially so the steam is forced to travel around the wall. The heavier water droplets hit the vessel wall and tend to coalesce and run down to the bottom. The stack protrudes inside below the inlet, so the steam flowing around the wall has to change direction again to go up the stack. It needs a bit of vertical height below the end of the outlet to accumulate a bit of water and force it out the drain.
Ideally, the lower section should be conical. As the steam moves down while whirling around the wall, it goes faster (conservation of angular momentum, like a skater spinning and changing posture). Commercial ones sometimes use parallel corrugated plated to cause the changes of direction so the drops impinge on the walls and run down.
I have attached a picture of one, assembled in the steam plant, and another with the stack removed so you can see the part hidden inside. (It started out shiny, but tarnishes incredibly quickly.) And it works quite well. The next one will have the stack vertical, something obviously slipped there. I catch a bit of water from the drain outlet at first, then when it is all hot, the water ceases. I get nearly no droplets out the top unless I have excessive carryover due to over-filling the boiler. You can see that in my case, it is all about function with no artistic input!
I tried a horizontal one for a lower profile, also in the pictures. The tube I had was too small for the body and it did not work. I suspect not enough height to separate out the drops when the tube was horizontal, and I had even more hot rain than without the separator. I have now obtained a larger diameter tube to try again.
If you want to incorporate feed water heating, I would suggest a coil for the feedwater water inside the vessel. This would require a larger vessel than I have used. But quite doable with say 38 mm or 50 mm or larger tube for the vessel. And as many turns as you can fit, which is more easily accommodated in a larger diameter vessel. The coil should be on the discharge side of the pump, as the pump will not like hot water. I tend to use 3/16 tube for the water and steam lines, but 5/32 might be ok. Of course if you want more heat transfer area, you can make a full on heat exchanger with many tubes, just like another boiler.
The heat lost to feed water will cause more condensation so you might need a bit more disengaging space above the coil.
MJM460
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MJM460 -
As always, very clear and comprehensive.
It's a bit like the steam version of the cyclonic funnel on a dust extraction system.
Your post offers a great resource which I shall use as my guidline when I come to build the separator / preheater - it's a text in its own right.
The only change I plan to make is to route the exhaust from the separator up the boiler chimney, so I guess that rather than have a chimney on the separator there would just be a steam out pipe.
Re your point about your work being functional rather than artistic - I really like the look of your work. The robust functionality has an aesthetic of its own, and to me it has a real beauty to it.
As always, thank you for your input and the time you spend in offering it.
:cheers:
gary
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Hi Gary, thank you, you are most welcome.
Yes exactly like a dust extraction cyclone.
You might need two sets of nut and tail connectors or pairs do flanges to connect the steam out pipe to the boiler stack connection, but yes, that’s the idea.
Hard to know how many turns to make the water coil, the water outlet can only approach but never equal the engine exhaust temperature which will probably be very close to 100C. Making the coil will be good practice for that flash steam plant. What ever you do will help your boiler steam output, but I expect the surface area of the coil will be the practical limit to how much you can achieve. Five to seven percent might be achievable.
Looking forward to seeing how you go.
Thank you for your comments about my engines. I enjoy making them, which is of course the whole idea.
MJM460
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I look forward to interpreting your suggestions and applying them in practice.
They certainly give me a direction but no doubt there will be further discussion ahead...
:) :ThumbsUp:
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Next up is the water reservoir. The body is cut from a bottle which was filled with Waitrose German Reisling which I had to get rid of before I could use the bottle :wine1:.
I chose it because of its deep turquoise green. I have never seen another wine bottle of this colour, and I thought it would suit the feel of the plant. The top cover is a nice cast brass ceiling rose from an old electric chandelier courtesy of the charity shop. I enlarged one of the two screw holes to accommodate the pipe to the pump. The other can... er... serve as an air vent :).
The underside of the rim had to be turned to fit the rim of the glass and there is still a bit more work to do on this to get a good fit. The stopper for what was the cable opening is made from an old brass drawer door knob plus a spigot which I turned from brass so that it sits nicely in the hole. The stopper assembly lifts out easily so that the reservoir can be refilled in situ using a funnel. I'll look out for a nice brass or copper funnel rather than keep lowering the tone with one of my blue plastic ones :)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/838998.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/838999.jpg)
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Looks nice :)
Next up is the water reservoir. The body is cut from a bottle which was filled with Waitrose German Reisling which I had to get rid of before I could use the bottle :wine1:.
Pleased to see you managed to cut the bottle on the first attempt. I am sure you would have hated to have to repeat the experience :paranoia:
Jo
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Thanks Jo.
Truth to tell, it is particularly brittle glass and I did break one. Or was it two? I can't remember...
And there were also the other ones that I bought in case of future breakages. My shop looks like the glass recycling depot at the moment...
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Well, I'm back from my travels and getting back into the shop, so will continue with the topic of the thread soon.
For now, though: one of the things I did when I was away was pay a visit to our forum friend Peter, aka Gas_mantle. We spent an enjoyable (and for me educational) couple of days coal firing his 5 inch vertical boiler and running a few of his engines on it.
Here he is with his newest - a vertical Stuart-like beastie (which I have just learned he calls 'Kermit' :) ). In the background is my trusty home from home - my Ford Transit camper van conversion:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840205.jpg)
And here is a detail shot of his elegant Potty Grasshopper beam engine:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840204.jpg)
A good time was had, including the obligatory beers of an evening!
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Cheers Gary :)
A good bit of steaming during the day and later in the evening getting myself steamed with a few pints of the dark stuff ;)
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:cheers:
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Hi, A really interesting project .. :popcorn: :popcorn: :popcorn:
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Thank you :ThumbsUp:
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A little bit of progress. Mounting block for pump - aluminium slab sawn and milled square enough and drilled and tapped M3 for the pump base:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840461.jpg)
And the underside drilled and tapped M6 for screws which will come up through the mounting board:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840460.jpg)
Steam separator/feedwater heater next...
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So... below is my CAD ('Clunky And Dodgy') diagram for the steam separator / feedwater preheater.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840538.jpg)
I hope it is more or less self-explanatory. Gratitude to MJM 460 for his technical advice, and to other sources found online. This is a bit of a synthesis, with hopefully a few touches of my own as it pans out.
Here are the some of the basic materials (based on 2" diameter copper pipe and fittings) which I acquired today:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840539.jpg)
All advice welcome. Please feel free to offer any ideas and changes you may have in mind - it's all part of the process...
:)
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Hi Gary, good to see that the good old back of the envelope still has it’s place in modern CAD.
I would suggest that the steam outlet is moved to the top in the centre, with an internal projection down below the inlet. The idea is that the wet exhaust steam has to start moving downwards, then has to turn back 180 degrees to the outlet. This change of flow direction helps the separation of the more dense water droplets.
It is also worth thinking about the detail of the lid. If those bushes, plus the third one for the outlet are made longer and set in holes in the lid, it is easy to locate them when soldering. The parts on the inside can be drilled for the ends of the internal tubes, and the outside can be threaded for your pipe connections. Might need some nut and tail connections or flanges to make it possible to assemble. You could even make it a flanged lid for maintainability.
How much heat you recover in the feedwater is limited by the exhaust temperature, probably very close to 100 C, and the area of tube in the coil, so wind as much as you can into the coil for more heat transfer area. I suspect the smallest radius you can bend the tube to will determine how many coils you can fit.
Looking forward to see your interpretation and how it works in practice.
MJM460
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Hi MJM -
Once again, thanks for your input.
Back-of-the-envelope is the future of design, you know.
Decent progress this evening.
I will move the steam outlet to the centre of the lid, as you suggest. I made the basic forms tonight, and had to drill a hole in the centre anyway in order to turn the form I had roughed out by chain drilling:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840669.jpg)
The hole will do nicely as the basis for the steam outlet. The bushes in my sketch above weren't really a complete idea. I still have to think the connections through, and I'm sure your thoughts above will help.
The main forms are shown here:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840668.jpg)
The stand will be carved from the aluminium tube, and there will be a layer of insulation between the cylindrical part of the copper vessel and the inside of the stand. The bottom of the stand will be cut away to reveal the cone, and a drain cock of some kind will be inserted into the blanking cap at the end of the right angle. The stand is taller than the separator so the bottom pipe and drain cock will be held above the 'ground'.
The cap has a circular locating groove which was milled into the underside on the rotary table. This will hold the top part of the separator in the correct position when I solder the cap on. The first joint down from the cap will be left as a tight push fit so that it can be taken apart for cleaning, etc. The cap is wider than both the separator and the stand so it will support the separator by sitting on the top of the stand. I reckon a nice little pitch circle of tiny screws fixing the cap to the thick wall of the stand will finish it off nicely at that point :)
When I get to the preheater coil I'll bear your advice in mind.
So, a bit more drilling and some soldering next...
Cheers :ThumbsUp:
gary
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Now, the cap, hand-fitted together at this point. Following MJM's suggestion, the steam outlet is now via a connector in the centre of the cap with a 1//4 " pipe, the end of which will be inside the separator lower down than the steam inlet, with the other end of the pipe going up the boiler chimney. The two outer connectors will bring water via 3/16" pipe from the pump into the coil and out to the boiler respectively.
The brass of the cap was thick enough to take a thread so I don't think any of these connectors will need to be soldered into the cap. I drilled the middle hole (for a turning mandrel - too big) before I knew I would be putting a pipe connector through it, hence the o-ring. Originally I was thinking of putting some kind of finial or knob on it to close the hole. Given the vessel is open to atmosphere I think the o-ring will be fine. If I get any steam leakage from the other two connectors I'm sure a twist of PTFE tape will fix it.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840741.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840740.jpg)
I can only avoid the torch for so long now... :Mad:
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Hi Gary, looking really good.
Remember, the vessel will be at atmospheric pressure, so sealing is no too difficult. The only pressure is in the feedwater pipe, so the tube connections to the coil have to be sealed against the full feed water pressure.
MJM460
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Thanks MJM.
Yes indeed - they will be.
gary
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... wind as much as you can into the coil for more heat transfer area. I suspect the smallest radius you can bend the tube to will determine how many coils you can fit.
MJM - by this do you mean that the pipe should be bent into as many separate coils - parallel to each other, 'clover leaf' style - as will fit into the body of the separator?
I had just envisaged one single coil with as many turns as possible, but am open to ideas. What do you think?
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Hi Gary, I am suggesting one long tube wound in a coil like a spring. However, as the connections are side by side in the lid, instead of returning straight back to parallel to the inlet, you might be able to just continue winding more turns in a second layer so there is more of the tube wound into the coil to maximise heat transfer area. It’s a matter of what is practical.
If you look in B and R’s book, you will see how their coils were arranged.
I strongly recommend against parallel coils where the flow splits into parallel paths. Even in full size with the greatest care to achieving symmetry of the coils, it is still difficult to get equal flow through each path.
MJM460
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That's great, MJM.
Thank you again for your clear advice and for sharing your knowledge.
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Gary
I was lookng at your sketch and reflecting on 'dry steam to chimney'. If the condenser does its job there should not be much in the way of dry steam as its temperature will have dropped. It will then be converted to hot water coming out of the drain. That water will have oil in it but if you could work on an oil seperator you could then feed the hot water back to the water tank.
Just thinking.....
Pete
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If you make the exhaust steam inlet tangential to the drum rather than radial, you will get something of a cyclone effect, as in Dyson vacuum cleaners, centrifuging out water droplets.
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Thanks guys.
@ Pete - well, that makes sense! I was thinking that only some of the steam would condense, with some left over to send up the chimney to draw the flame (I have found that the blower - when used - sometimes helps focus a kerosene, alcohol or even gas flame into the bottom of the boiler). From what you are saying I guess that if anything does come out of the exit end of the separator it might be quite a gentle flow and that might actually be quite good to just gently pull up the flame. But we shall see. Your point has got me thinking that the thing for me to do is to first trial it without connecting the outlet to the chimney. If nothing is coming out there won't be much point in hooking it up, but if there is some outflow - event slight - I think it would be worth routing up tthe chimney.
@ ChucKey - agreed. Or like the cyclonic separator in a shop vac system. Already part of the plan! :ThumbsUp:
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That water will have oil in it but if you could work on an oil seperator you could then feed the hot water back to the water tank.
Just thinking.....
Pete
That's a thought, Pete, though I'm not sure I want to take this plant that far.
gary
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Wahey!
Silver solder day. :Mad:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840857.jpg)
Below: the top half. The brass cap was silver soldered on to the copper tube. This picture shows the steam inlet pipe - which enters the vessel at a tangential angle - just before I soft soldered it into the hole. This was the only soft soldering I did today.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840856.jpg)
The main body of the separator is pretty much done. All of the joints on the bottom half are silver soldered, but the middle joint is left as a push fit so that the vessel can be opened up for cleaning and so on. If there is any leakage from this I'll cross that bridge later, perhaps with some silicone. As noted above, this isn't a pressure vessel:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840855.jpg)
I'm waiting for an outlet valve with matching bush to arrive. When they do, the end cap of the 90 degree bottom tube will be drilled and the bush soft soldered into it. The next step after that will be the coil.
I'm not the neatest solderer in the world, hard or soft. I guess a lot of it is just practice. However, I'm not unhappy with the overall result, especially since most of it will be hidden inside the aluminium stand.
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Your WorkMate looks like mine - pile of partly broken fire bricks, some scorches on the wood... Well lived in!
:popcorn: :popcorn: :popcorn:
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I'm in good company then!
The first time I silver soldered it took me by surprise - I set my actual shop bench on fire. Plastic containers on the shelf above were melting with the heat from the torch and it was raining stainless steel cap-head screws...
:Mad: :Mad: :Mad:
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The steam valve and bush arrived today so this evening I was able to drill the end of the drainage pipe, soft solder in the bush and trial fit the valve. Again not the neatest soldering in the world (everything runs - maybe I need thinner solder wire?) but it will be fairly well hidden when it's done and at least the valve hasn't ended up crooked. For the delicate soft soldering of the steam in pipe and the valve bush I bought a cheapo fine flame blowtorch at B&Q yesterday and I must say it's excellent for this kind of work:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840934.jpg)
Then the chickens came home to roost. I had begun to get the idea that I might have been premature in silver soldering the cap on to a fairly long tube section before fitting the coil, as it was going to be a faff trying to fit and tighten up the union nuts on the coil inside the cap when the coil was in the way. I got the first end done easily enough before I wound the coil:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840933.jpg)
Then with that end still attached I wound the coil round a bar of acetal held in the vice. The entire length of the coil used my remaining length of 3/16" pipe with nothing to spare:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840931.jpg)
But getting the coil into the tube was a mission to say the least, as I was working against two straight verticals and the 3/16" tube was work-hardening by the minute. I had thought of putting an elbow at the bottom which would probably have made life easier - but I didn't. This was probably not the best way to go about it but I think it all goes back to my earlier step with the cap. A simple flanged cap as MJM suggested would have been much easier to manage. The first union nut that I had tightened worked loose as I manhandled the coil, so now I have the awkward job of reaching in past the coil and tightening all three, including the one on the vertical steam out pipe in the centre of the cap. I have nothing that will reach in there so I'm going to have to make a long thin right angle spanner for each of the two sizes of nut.
The other issue was that I could only push the coil so far into the cap before the straight sections prevented it from going any further. In the picture below, although you can't see it, the top of the coil (before it turns into a straight run) is only just over a third of the way up the top half of the vessel:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/840932.jpg)
This bothered me at first as I feared a loss of efficiency, but the idea then dawned on me that probably all I need to do is to make the bottom end of the central steam out pipe longer so that it goes down quite far through the coil towards the bottom of the vessel (though clearly not so far down that the end will be immersed as soon as condensate starts to collect!). That way the steam will have no option but to descend into the depths of the coil before it can find its way out of the separator.
It also occurred to me that the bit of empty space above the coil where the steam comes in might not be such a bad thing either as it may give the steam a chance to build up a bit of a cyclone witthout interference when it first enters the vessel. This last point might be wishful thinking on my part - I'd be interested in any views on this. And on the rest of it of course...
So I need to make two tools to tighten the nuts, but other than that it seems to be goiing ok if my hypotheses above are correct. As a by-product, I have also realised that winding the simple coil for my flash steam plant (featured in another thread) should be a breeze...
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Not the most inspiring pictures tonight, unfortunately.
Because of my design issue of making the top section too long, it was a right game tightening up the union nuts on the coil on the underside of the cap. You can imagine. I tried making a right angle spanner-like tool out of a bit of steel, but that proved to be too flimsy and it bent even though I had hardened it. In the end I just took a perfectly nice 10 mm spanner, put the business end of it in the vice and bashed it into a right angle with a hammer. For shame! Sheer vandalism, but it did the trick and I was able to get the internal coil connections to what I believe to be watertight.
With that done it was even trickier to tighten the connection on the central steam outlet pipe, so I re-thought it and drilled and tapped the central hole in the cap M12, then turned an elongated bush from brass with a slight taper on one end and an M12 thread on the other. This was drilled through for a sliding fit on the 1/4 " OD pipe and screwed into the hole in the cap. The threads fit nicely, but a hank of PTFE tape and a blob of Stag Wellseal will ensure that no stray steam escapes:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/841301.jpg)
I then ran a length of the pipe through the bush with the bottom end at what I guess to be about the right depth in the vessel and plenty to play with sticking out the top. A union nut and nipple were added at the top and the assembly was silver soldered up. Here it is in situ:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/841300.jpg)
This more or less completes the working assembly of the steam separator / feedwater preheater. I will use some of my self-amalgamating tape to make a seal between the top and bottom halves of the vessel, which will be ok because it won't be seen. I'll also insulate the main part of the body with ceramic fibre - ditto. The aluminium stand will cover a multitude, and that is what I'll tackle next.
Shiny toys!
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Hello Gary,
Still following and watching :popcorn:
Have a great day,
Thomas
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Many thanks Thomas.
You too 8)
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Hi Gary, good to see you managed to get the coil in. Well done on that. I was wondering how you would do it after soldering the top on to the cylinder first.
Remember that the water inside the coil is at full boiler pressure, so silver solder as many of the joints in that tube as you can. All the joints which only see exhaust steam operate essentially at atmospheric pressure, so are the easier ones to seal.
MJM460
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Hi MJM.
Getting the coil in was a mission, to say the least - both actually getting it in there, then tightening the nuts. Serves me right for not thinking it through properly. I don't think it's too bad a job in the end, though.
There are only two connections in the coil, and these are where it joins the cap. They are made with pipe nipples silver soldered on to the ends of the pipe and secured with union nuts. The unions are screwed into threaded holes in the cap. It's the tightening of the union nuts that makes the seal, and I *think* I managed to get them watertight (probably steamtight in fact though they don't need to be). I'll test these connections with an engine run under steam before final assembly though.
The joints at atmopsheric pressure shouldn't present too much of a problem, as you say.
:ThumbsUp:
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Just back from working away from home, but managed to squeeze in a little bit of shop time this evening.
Milled a notch into the thick-walled aluminium tube that will act as a stand and jacket for the separator to provide access for the steam inlet pipe and to centre the separator in the stand:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/841505.jpg)
Like the steam inlet pipe, the sides of the notch are tangential to the bore of the stand.
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The housing (a better term for it than 'stand') for the separator is quite tall, and when combined with the height of the chuck on the rotary table it is beyond the capacity of every machine in my shop apart from the big floorstanding drill press:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/841648.jpg)
The plan is to make a bolt circle in order to attach the cap to the housing. I'm going to use M2 cap head screws for this, with a tapping drill size of 1.6mm. The chuck on the drill press won't hold anything that small, but it will hold a very small Jacobs chuck that I have, which will in turn hold the drill bit. This arrangement produces a certain amount of runout, but I think the centre drill which you can see here will counteract that. The dividing plate attachment on the rotary table enables the correct spacing of the six holes. Note the mill table which I have fitted to the drill press - it's a very handy addition. Recommended!
I got as far as centre drilling the holes (as in the photo below) before I had to leave to go away until midweek. Once they are drilled and tapped I'll use transfer screws to mark out the positions on the cap.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/841647.jpg)
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So.
Holes drilled and tapped:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/842082.jpg)
So far so good. But next comes a comedy of errors. Because I had already silver soldered the top half of the separator to the cap, and not having any long series drills, I decided it would be necessary to drill the clearance holes for the fixing screws in the cap from above to avoid a foul-up between the drill chuck and the top half of the separator. I put four transfer screws into the holes in the housing, turned the cap assembly upside down and set it all up to transfer the holes by giving a wooden block placed on the other end of the housing a sharp tap with a wooden mallet:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/842081.jpg)
However, it didn't occur to me that the position of the steam inlet pipe would be a problem. It should have, but it didn't. The four holes transferred nicely (I only have four M3 transfer screws), but due to the fact that I had positioned the holes in the housing somewhat randomly relative to the notch for the pipe, the position of the notch caused the pipe to lever the cap round and throw the holes in the cap out of alignment with those in the housing when the cap was turned the right way up:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/842080.jpg)
Rookie error! :facepalm:
I initially thought of widening the notch, but then decided to try to bend the tube to a more forgiving angle. The tube did not bend. The soft solder sheared, and the tube came out:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/842079.jpg)
:facepalm: :facepalm:
I'll have to solder it back in again at a better angle, after which I'll transfer and drill the two remaining clearance holes.
Not a major disaster, but the result of not thinking through the sequencing issues properly, and it's striking how a mistake early on can make its presence felt through subsequent steps.
Still, at least I now shouldn't have to widen that notch in the housing, and the drilling, tapping and transferring of the holes seems to have gone well...
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Managed to make some reasonable progress before I went on holiday and today having just got back.
The cap is now in situ, fixed with stainless M3 pan head screws:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843069.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843068.jpg)
Work then began on the aperture at the bottom through which the drain valve will protrude.
Centering the housing on the drill press:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843067.jpg)
Cutting the aperture with a hole saw. This went quite well, and overall the aperture looks fairly neat. Inside the housing there is a gouge at each side as the hole saw cut vertically through the sides of the tube. I'm going to leave this be as any attempts to tidy it up will probably just make it worse. In any case the gouging is pretty much internal and doesn't really harm the overall look. It's visible on the finished assembly but you have to peer a bit to see it. No big deal.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843066.jpg)
I had a nice thick brass ring left over from a failed attempt at making a meths burner housing. This just needed a little drilling to convert it to a base for the separator housing. I centred it by eye under the housing and marked it out...
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843065.jpg)
... then drilled three clearance holes to allow it to be fixed to the bottom of the housing courtesy of three corresponding holes drilled and tapped M3. These three holes are a bit out of alignment with the existing outer holes but that won't matter as only the outer holes will be seen. They will be used to fix the asssembly to the base board of the plant.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843071.jpg)
I used both transfer punches and transfer screws to mark out the various fixing holes in the cap and the base. They are extremely handy for accurately transferring hole positions.
Finally, the basic assembly in a more or less complete state:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843070.jpg)
There are still a few bits and pieces to attend to and the whole thing will benefit from a bit of a shine up. Getting there though...
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Looking good Gary. Great to see progress already after returning from your travels.
One thing to note, that combination of metals will over time give you corrosion problems if it ever gets wet, which it almost certainly will. The Aluminium tube will do a great job of protecting the stainless screws and the brass by sacrificing itself.
Fortunately there is a simple solution. You might know that most yacht fittings are stainless steel, while masts and booms are mostly aluminium. Any yacht chandler will have a small tube of paste to use as an insulating barrier. It works well even in salt water environments.
So when you get to your near final assembly, put a smear around the top of the aluminium stand and a dob on each screw before you insert it. It works very well, and will avoid unsightly corrosion, and ensure that you can always pull it apart if necessary. The one I use is green, just wipe off the excess with a paper tissue or rag, but other brands may be a different colour.
Looking forward to the next steps.
MJM460
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Hi MJM, and thanks for your input once again.
My knowledge of the dark metallurgical arts only extends so far as knowing that 'some metals in contact with each other can cause corrosion', but without any real clue about what metals will do that. Your advice, therefore, is very helpful. There are a couple of yachting chandlers near where I live so it should be easy enough for me to get some of the goo you recommend.
Cheers...
:ThumbsUp:
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'some metals in contact with each other can cause corrosion', but without any real clue about what metals will do that.
Electrode potentials.
The greater the potential, the greater the risk of corrosion. There does need to be an electrolyte ( usually water ) present.
http://www.efunda.com/materials/corrosion/electrochem_list.cfm?sort=com
From the table copper is about +0.5v and zinc - 0.75v so if you poke a bit of each in a orange / potato / whatever you'll land up with a 1.25V - ish battery. :)
No great current draw possible but it will drive a red LED, or sometimes a very small motor
From memory the copper will eventually disappear hence the expression 'sacrificial anode'.
There is a fair bit more to it but I've long since forgotten .... :old:
Oops .. starts here:
http://www.efunda.com/materials/corrosion/corrosion_basics.cfm
Dave
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Thanks Dave.
I have no doubt that this information will be useful in many other projects too.
gary
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I had to redo the soft soldering of the steam outlet pipe because I got all the angles wrong first time round. This was a messy and time consuming business but I got there. I then water tested the connections on the coil at the top of the separator and they appeared to be watertight. So, the way forward was clear...
The top and bottom halves of the main vessel were pushed together and the join covered with self-amalgamating tape. But for MJM 460 I wouldn't know this stuff existed, but it seems ideal for the job in hand, bearing in mind that this is not a pressure vessel:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843748.jpg)
Next, the separator was lagged in ceramic fibre insulation material secured with fine copper wire:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843747.jpg)
And, bar a few lotions and potions, that's pretty much it. I'll call it done for now:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/843746.jpg)
Given that all of the main components are now done, the next step is to think about the layout of the plant as a whole and consider what material I'm going to use as a base board.
Will be interested to know what other people would use!
gary
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Hi Gary, that’s a fine looking separator. Now to see how it performs.
I am not sure that I would have used the self amalgamating tape for that purpose, but it is very useful for a layer of insulation on the steam pipes. However, as you say, it is not a pressure vessel. Now that you have started soft soldering, you will have difficulty doing any further silver soldering, but again, it is not a pressure vessel. I think I would have put a few rivets in, even if only loose, just to hold things in place and then soft soldered the seam. Perhaps next time. But there are many lessons in the journey to a handsome feature of your steam plant.
I just use a piece of chipboard for a base board, either melamine covered as in typical kitchen shelving to keep it waterproof, or just a few coats of polyurethane, again to make it waterproof. Otherwise it tends to swell and disintegrate due to the inevitable water spills. Ideally, eventually, I would like to tidy them up by adding brick like trim or more paint to make it look like brick or concrete, but perhaps that will wait until my model making skills are more advanced.
It is interesting that you chose to insulate the separator vessel inside the aluminium stand. You are using the exhaust heat for boiler feed water in the coil, so don’t want to loose it unnecessarily, but then you are discharging the exhaust, so the more that condenses, the less moisture into the shed, assuming you are in a shed. Perhaps another area for some experiments, by trying a few runs with that insulation removed once you see what it does with the insulation.
MJM460
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Thank you MJM. Glad you like the look.
Apologies - I should have made it clear that your recommendation of the self-amalgamating tape was related to something else, not this. However, I have a feeling it will be ok in this application as the two sections of pipe that comprise the vessel make a really tight push fit. It can be quite hard to pull them apart by hand so unless that changes under heat, the tape is really just to close off any odd gaps round the perimeter.
I also thought about the dilemma of the insulation, and opted for your first point, i.e. to maximise the heat going into the feed water by preventing it from escaping through the walls of the vessel. But yes, as you say the condensing effect on the exhaust will be compromised. I guess it's a case of 'suck it and see' and trying it with and without the lagging.
Regarding the base board, my ideal would be a piece of the kind of smooth black slate that is often used to make fireplace hearths. That would look great, but it would be (a) expensive, (b) heavy and (c) unforgiving of any drilling errors.
I might prefer plywood to chipboard, possibly with a dark stain to camouflage any scorch marks. Or a slab of aluminium perhaps...
All ideas welcome!
-
I decided on a piece of plywood 20 mm or so thick for the baseboard. It will be varnished in a dark mahogany colour when it's done. The basic layout is below. I intend to put a displacement lubricator between the
separator/preheater boiler and the engine - I'll probably just buy it rather than make one. I also have a tiny electric motor which will hopefully work as an engine-driven generator powering a small led lamp - these will be placed at the front of the board (the bottom in the picture). Some components will be screwed to the board from above with wood screws; others will be fixed from below with machine screws, in which case the holes will be countersunk and/or counterbored on the underside of the board. Counterbored holes will be reinforced with washers epoxied in. I think that this will suffice rather than making threaded inserts. As a final touch, some kind of angle bead will be fixed round the outer edges of the board.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/844788.jpg)
Starting to take shape but there's still plenty of plumbing and other stuff to do yet...
gary
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Hi Gary, looking good.
You can see that the complexity builds quite quickly when you set out to make a complete steam plant. It would be worth making a sketch schematic ( I.e not to scale) to show where all your piping must go to get all the components in the right order. Piping runs will determine (along with access) the orientation of components. Piping runs can be much simpler and tidier if the location of components is carefully chosen.
Remember the lubricator must go in the steam line between the boiler and engine, preferably close to the engine and with its outlet equal or higher than the engine steam inlet. You don’t want oil in the boiler.
Thirty eight already here and it’s only 10:30 am and only November. Not even summer yet. Hardly need a preheater for the boiler. But we are expecting a cool change later in the afternoon which should drop the temperature to a more comfortable level quite quickly.
MJM460
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Good tips on the piping from MJM, be bad to get most of the way through and have two pipes or fittings inrterfere. There is the high-tech route with drawings in 3D, down to the old school (and sometimes fun-ner) way of mocking it up with something like pipe cleaners. I remember mocking up sailboat cockpits with boards, crates, and extension cords.
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Don’t mock the pipe cleaners, Chris. We used to build whole refineries with plastic tube and moulded fittings, and made up pressure vessels all to perfect scale. Then attached labels with the dimensions and went direct from that to isometric drawings of individual pipes with material lists for the welders. No layout drawings.
Main problem was the plastic tended to melt if we tried to fire it up to see if it would run. Also turbines were lacking in internal detail!
That was real 3-D modelling, way before all this virtual stuff.
MJM460
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Don’t mock the pipe cleaners, Chris. We used to build whole refineries with plastic tube and moulded fittings, and made up pressure vessels all to perfect scale. Then attached labels with the dimensions and went direct from that to isometric drawings of individual pipes with material lists for the welders. No layout drawings.
Main problem was the plastic tended to melt if we tried to fire it up to see if it would run. Also turbines were lacking in internal detail!
That was real 3-D modelling, way before all this virtual stuff.
MJM460
I am not mocking them, I am serious about using them! In a mock-up. I would mock trying to put steam through them!
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Yeah, pipe cleaners would not even handle low pressure air. Come to think of it while our plastic tubes would have been ok for low pressure air, the elbow and tee fittings, valves etc were all solid. Fortunately we had other methods to check that things were likely to work.
MJM460
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Hi guys -
My temporary lapse of thinking regarding the position of the displacement lubricator (now corrected above) notwithstanding, I believe I have a reasonably clear image in my head of the piping. However, the pipe cleaners mockup is a great idea. Don't think I have seen a pipe cleaner for decades but they are no doubt still out there (after all, what else would people clean their pipes with? While I suspect that pipe-smoking has gone into decline as vaping has ascended, surely it cannot be extinct!). Amazon is my friend...
Intriguing, MJM, that you would build small scale models of whole refineries using Blue Peter methods and materials. :)
Hot in Australia, cold here in Britain. I tend to prefer the cold but a happy medium would be good...
Thanks both for your input.
gary
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Pipe cleaners ordered!
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The pipe cleaners have not yet arrived, so rather than pace up and down fretting I transferred my attention to making a handle for the boiler feed pump:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/845174.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/845173.jpg)
The grip is aluminium, the shank a random piece of steel of unknown kind that I inherited with a lathe I bought a few years ago.
I'm pleased with the chunky undercut thread on the shank and the curved profile of the shank (which took quite a lot of work with files and abrasives in the lathe). The overall finish is reasonable and I can always go back to it again if I decide to. I am definitely not pleased that the slot at the bottom of the shank (to fit over the brass handle of the pump) is off-centre. I have no idea how this happened. I used an edge finder on the insides of the vice jaws and the 1/2 function of the DRO before cutting it with multiple passes of a small endmill.. Maybe I wasn't as accurate with the edge finder as I should have been - I don't know. I'll get away with it because it's only a pump handle and the slot will be covered by a collar. I most certainly will not get away with it when I get to building my second engine, so I need to address this.
I also reckon that some people may feel that the handle asssembly is a bit big and somewhat out of scale with the rest of the plant. On the other hand, it should be a nice chunky handle to pump water with.
Still on track, the inevitable imperfections notwithstanding...
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Well, since none of you have talked me out of using that handle on the basis that it's visually too big for the plant, I've decided that I might as well talk myself out of it. It's too big for the plant. Or is it? Dammit, I don't know...depends on how you look at it... but certainly I have thought of other applications in which I could use it, so we'll see...
Meanwhile, here's my little oil refinery in development. Welcome to pipe cleaner heaven:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/845232.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/845231.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/845230.jpg)
Looking at it might make you go crosseyed, but I think it more or less makes sense. The photos make some of the pipe cleaners look as though they are angled all over the place, but in fact they are pretty much arranged in right angle bends (I have a few elbows in my box that might be nice to use). The red pipe cleaners represent lagged pipes, the blue ones bare copper. The spiral bits are just where I have wound the pipe cleaners around existing pipes, and the bit of blue near the engine represents the displacement lubricator (winging its way as I type).
Apart from any other comments any of you may have, I only have two questions:
1. I have designated the pipe routing steam up the chimney from the separator as lagged. Should it be so?
2. How do I get water and steam to flow through the pipe cleaners? I have looked and they don't seem to be hollow in the middle. Can't for the life of me figure that one out...
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Ask Santa to bring you some very thin long Drills?
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Ah... so that's how it's done! Yep, makes sense...
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Ask Santa to bring you some very thin long Drills?
Aircraft extension drills.... :Lol:
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Amazon is my friend...
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My vote is keep pump handle as it is. I think it is in keeping with the engine,, something different. :ThumbsUp: :old: :DrinkPint:
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Hi Gary, looks like it’s time to make up some tube connectors, and bend some copper tube, now you have the 3-D patterns.
You asked about insulating the outlet from the separator/feed water heater.
Insulation is normally applied for one of two reasons, or perhaps even both. The obvious one is for heat conservation, and the other is for personal protection. In this case, heat conservation is not really required, though if the outlet steam gets to the top of the stack before it condenses, it will more readily be dispersed into the atmosphere as extra humidity rather than raining inside your workshop. So I would suggest in this case the main issue is personnel protection.
In the oil industry, and I assume power generation is similar, personnel protection is required if the surface is both accessible for accidental touching and above 65 deg C, above which burn injuries are considered likely. Probably a bit of a safety margin in that, especially if you are an experienced welder with tough skin, but the line has to be drawn somewhere.
You might be interested to know what happens if the pipe is hot enough to cause injury, but process reasons require cooling. In such cases, a cage is made from expanded metal mesh and supported of the pipe by appropriate brackets in the accessible areas, for example where the pipe passes through a platform.
The exhaust steam in that pipe will be a mix of steam and air, so the final temperature after the feedwater has absorbed what the available heat transfer area will allow, is a bit hard to guess, but it will probably be a little above 65, but certainly less than 90. Considering the nature of the plant as a whole it is probably not the biggest injury risk you need to be aware of, so I suggest that you can take your choice.
MJM460
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Gary......
I found the DuBro 1/8" & 5/32" OD bending spring & wasted so many bends as being inaccurate in the set of and badly rippled inner surfaces, despite pre annealing the bend area
I finally purchased a pair of DuBro tube benders for the above sized tubes and find the K&S 1/8" & 5/32" OD brass tube can require 2 or 3 annealings until red hot, then air cooling after each annealing can achieve a smooth 90 degree bend with absolutely minimal surface rippling on the tube inner radius surface
If you read & view images of older :old: full sized steam plants pipe work, you will note 90 degree bends, with pipe spools set in 3 principal planes.....yes 'vertical', 'horizontal' and 'across'
Parallelisim of pipe runs is also an aspect point as viewed that follows for the 3 planes mantioned
There is no use of 135 degree bends :facepalm: or angular set of any pipework
So after realisation of the above my scale tubework [generally] follows these principals
Derek
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Hi All.
Many thanks for your input.
@ JC54 - on the handle - you have emboldened me! It's quite a big handle but it's not like the plant is a 'model of' anything, so there's no predetermined look for it to spoil. And yes, I suppose it does sort of go with the engine, so I am now one step closer to keeping the handle as is. :ThumbsUp:
@ MJM460 - educational, as always. I'm not too worried about the safety angle in this instance. As you suggest it's relatively minor (and I have been burned too many times to care...). What I'll do is run it with the pipe in question left bare, see what it does and then decide whether or not to lag it.
@ Derek - I agree with you about the 90 degree bends. It's certainly my intention to keep everything as square as possible. However, I have these:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/845454.jpg)
I have quite a few of these elbows and straight connectors for both pipe sizes (3/16" and 1/4"). Using elbows instead of at least some of the bends would probably make life easier in that cutting straight pipe lengths and silver soldering nipples on to them will be easier to keep accurate than full pipe runs with several bends in them. However, will using elbows instead of bends impair efficiency by creating more drag on the steam passing through? Or would the difference be insignificant in a plant of this size?
And why do I find myself thinking that that last question has MJM's name on it...? ;)
@ Derek - thanks for posting the photos. Great looking plant! What is that you used for the pipe insulation?
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Gary.......the advantages of using those demountable elbows you show are many indeed, the single biggest disadvantage is in the hot steam tube to the engine & the mass of the fitting body, tails & nuts all consume more heat energy that a bent tube...same naturally applies to straight unions........a Golden rule is to keep the hot steam line a short as is reasonably practicable
In many installations, you may have a lubricator and then a regulator in the steam line between the boiler & the engine....so these must be considered & also lagged if possible
So the greater the material mass of the hot steam tube reduces the temperature of the steam & increases the formation of condensate/water
There is certainly a lessor issue with return lines, although it is best maintain the hottest exhaust steam temperatures the let the de-oiler perform its task
The tube insulation is pretty simple.......cotton twine [1.5 mm diameter] + a drop of Superglue......then wound progressively over the tubing....around the bends as needed & ended with another drop of Super glue........layer & paste a Home Brand Celulose type Polyfiller over the cotton twine to your required thickness....I chose say 2 mm deposit, then sand with 140 grit paper gently and progressively in sheet or tube format until you end up with a uniform thickness of ~~ 1.5mm depth......paint with oil based primer + oil based top coat
Derek
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Ah yes, that makes sense, Derek.
Not so much about friction/baffling effects; more about heat loss. Right enough, now that you point it out it's a bit self-defeating to lag pipes then stick a big heat sink in the middle of them. so... I will use the elbows where it doesn't matter (e.g. the cold water feed) and bend the others.
Thanks also for the recipe for lagging the pipes. Not sure I will do it the way you describe, but will certainly consider it.
Cheers,
gary :ThumbsUp:
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Hi Gary, a bit slow on taking my cue, it’s been a busy morning.
On the pressure drop, yes, a change of direction involves more pressure loss than the same length of straight pipe, though as you suggest it’s not a lot in the great scheme of things. The component of velocity in the direction of the straight pipe is reduced to zero, involving the loss of one velocity head of energy, and it is a loss, not converted to extra pressure. Then the flow has to be accelerated in the other direction, which takes another velocity head. Obviously the two occur in a gradual transition rather than in sequence, but the total effect is similar. The important thing to appreciate is that velocity is a vector and has direction. Maintaining the same speed of flow around a bend does not avoid the issue.
If you have a sharp bend, such as the intersection of two drilled passages in a solid fitting, there is even more energy lost in turbulence created. There is less turbulence in a smooth sweeping bend so less energy loss. The standard data for a forged pipe bend of the standard radius is about 13 times the equivalent length of straight pipe. So for 1/4 in. tube, about 3 inches of extra length. You can see why I say overall it is not much. But bending the tube avoids the cost of the fitting as well as in principle being the right direction on energy losses if you are after the last bit of performance. You do what fits when you have plenty of pressure which you are dissipating in a control valve to run an engine slowly, as pressure loss is not a problem.
On the heat loss issue, Derek is quite right that it takes heat to get the extra metal in those fittings up to steam temperature. That certainly results in extra condensate when you are starting from cold. However, providing you insulate them well, the extra heat loss once warmed up is only due to the extra surface area, and easily managed by a bit of extra thickness of insulation, so again, not much of a problem in the grand scheme of things, especially with that good condensate separator you have made.
It might not be immediately obvious just why refinery piping is always run parallel in the three orthogonal directions. Cutting across at an angle would obviously involve a shorter length, hence lower cost. Basically the parallel runs allow the most usable space for future additions, while the remaining open space is more friendly for cranes and other maintenance equipment, so not only to look tidy. A singly line across a pipe trac at an angle can block hundreds of meters of otherwise useable space where the pipe supports are already in place. In your plant you may prefer graceful curves in keeping with your engine design. It’s up to you.
MJM460
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Thanks MJM.
Putting this all together, I reckon I'll try to avoid using couplings where it's reasonable to do so, but not be too phobic of them for the tricky bits and where it doesn't matter.
As for the aesthetics - good point. Graceful curves are nice, but then so is a bit of juxtaposition of organic and geometric. I'll play it by ear...
Fascinating to learn about allowing space for service vehicles etc among refinery pipework. Obvious if you are in the know, I suppose, but what lay person would have thought of it?
All the Best,
gary
:ThumbsUp:
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The displacement lubricator arrived today. PM Research LUB-2, 2" long, 3/16" x 40 thread. All the way from the USA. Here it is, along with the tee by which it will be connected into the system, lying on the baseboard which is now looking pretty good after five coats of water-based gloss woodstain/varnish in a 'dark mahogany' hue:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/845975.jpg)
I guess I could have had a go at making a lubricator myself but it strikes me as being something of a mission and I'd rather devote the required amount of time, energy and angst to something more substantial.
As for hooking it up, here's exactly how I plan to do it (3:35 to 5:07):
https://www.youtube.com/watch?v=y9o6dXWGE10
Now that I have this part and the baseboard is varnished, I can finalize my layout and start screwing things down and piping them together.
:cartwheel:
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It appears to be green at this end of the planet too.
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/846061.jpg)
Duralac Green. Preventing Corrosion Between Dissimilar Metals. In a Shed. Near You. Now.
Another handy tip (one of many) from MJM460.
:ThumbsUp:
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A bit of progress today.
Yesterday the original flat brass handle of the water pump was glued into the slot in the new steel shank with Loctite 638. Today, I drilled two cross holes and tapped them M5. Two M5 screws were then secured in these holes using Loctite 2400 Threadlocker (blue in colour):
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/846192.jpg)
Tomorrow or the day after, when all the adhesive has set, I will cut off the ends of the scews and grind them flush with the shank. After that the plan is to machine a brass sleeve just long enough to cover this joint and fix it in place witth 638.
A locating ring for the water reservoir was machined, and this was fixed to the base board, as was the steam separator/feedwater preheater. The undersides of these (which directly contact the board) were smeared with silicone to prevent water from being drawn under the parts by capillary action. All points of contact between dissimilar metals (aluminium, brass and stainless steel screws) were treated with the ghastly green goo. Where the part fixed to the baseboard is brass, stainless steel screws were used, and where the part is aluminium, the screws are brass. Just for the contrasty look. Having a couple of the main elements fixed to the board feels like a real step forward:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/846191.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/846190.jpg)
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Some beautiful work in this thread Gary. Nice job.
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Thank you very much Stuart. Very kind of you.
gary
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The finished pump handle. The two cross-screws were sawn off and ground flat, and a collar (turned, drilled ad reamed from a piece of 'scrap' brass) was slid down the shank and secured in place with lime-flavoured Loctite 638. The grip was then fixed to the top of the shank with blueberry-flavoured 2400 'Threadlocker'.
All in all I'm pretty pleased with the result, even if progress has been slow due to winding down work for the year and winding up the seasonal celebrations. Many thanks to JC54 above for emboldening me to stick with my original aesthetic:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/847293.jpg)
Hope you are all having the Coolest of Yules and a Fabulous Festive Season.
gary
:cheers:
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Nice work Gary! All the best of the season to you!
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Cheers Stuart - you too.
:ThumbsUp:
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A slight digression into seasonal gifts received. These were from my Daughter (of whom Keith Appleton would be proud):
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/847343.jpg)
And these were from my Good Woman:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/847342.jpg)
How did they know what to get for me?
They must both be developing mind-reading skills...
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Very nice. I'm sure you dropped just the right amount of subtle hints. Catalogues left open on the kitchen table with convenient circles and arrows drawn on them on such..............
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.... sort of thing. And e-mails containing links to suppliers with 'get me this!'.
:)
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The first stage of the pipework is now done. Intrigued by MJM460's explanation about the practical benefits of a square format in full sized oil refineries, I decided to go for that (or as close to it as I could). I aslo thought it would contrast nicely with the curved shapes in the engine and elsewhere:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/848042.jpg)
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/848041.jpg)
Overall I'm pretty pleased with the look, but there was a setback. I plan to test run the plant to ensure that the separator works before I go as far as lagging the pipes. However, when I was machining the tee connector that links the displacement lubricator into the system (according to Keith Appleton's advice - see video above), a moment's complacent inattention at the lathe mangled the tee, cracking the metal and rendering it useless. Pretzeled, as some of you gentlemen from across the ocean might say. The highest level of enpretzelment was attained. I just put it into the system in its sorry state for the sake of the photos (in which it looks ok but isn't). This was on New Year's Day and I'm now waiting for the replacement to arrive. The good news is that in all other respects the modification of the tee went smoothly and the threads match those on the lubricator nicely. Patience...
Have a great 2020, you all!
:ThumbsUp:
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Bummer about the tee, the rest of it is looking great, looking forward to seeing it run!
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Cheers Chris.
It always seems to happen when I get too pleased with myself. Bet I'm not alone in that... :)
The new tee will arrive soon, though the need to earn a living looms large once again and time to play will be curtailed...
:cheers:
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Looks wonderful Gary. Pity about the Tee, but you'll get past that. These things are sent to try us and all that.
And no - you definitely are not alone in that. Pride cometh before a fall. Why I have to keep learning that lesson I do not know.
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Thanks Stuart.
Yes, it seems to be a fundamental principle...
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Well done on that piping, Gary. It looks really nice.
A pity to have to cover it all with insulation, but that is thermodynamics.
Perhaps we have to work out how to cover the insulating material with a metal protective shearing from brass shim. Or perhaps that is going too far. Derek makes his look quite nice with white paint or something similar.
MJM460
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Thanks MJM - glad you like it.
Agreed - shiny copper does look great as long as it's kept polished, but it would be sensible to add some insulation.
Derek's does indeed look great, but I'm not planning to do quite as thorough a job as he did.
Currently my aim is to use a tight, thin layer of self-amalgamating tape (your suggestion) and then a layer of string on top of that, then finally paint.
I'm thinking that that may provide a reasonable degree of insulation while not being too involved or too bulky.
Thoughts welcome, of course...
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The new tee arrived and this time the machining of it went smoothly as I was on my guard against foulups. Here it is attached to the lubricator:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/848561.jpg)
Once that was installed in the plant it seemed sensible to fire the whole thing up to make sure it worked before going on to the final stages such as lagging the pipes, finishing the base, etc. It may not be the most efficient plant in the world but it certainly works:
https://www.youtube.com/watch?v=aGtS9f-lxw8
I noticed that with the separator/preheater in the system the engine seems to run more slowly but with more torque. Is that what one would expect?
I was pleased to find that the separator works. I emptied about 100 ml of condensate from the bottom drain cock over the course of just under an hour:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/848560.jpg)
As a novice I have no idea whether or not that is a decent yield of condensate, though I'm sure some of you guys will. What I do know is that this 100 ml of liquid is better in that jar than as condensation all over my lathes, mill and drill press.
:)
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Looking great! Love the layout of it, coming down to the last touchs. :ThumbsUp: :ThumbsUp: :ThumbsUp:
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That's great Gary - really nice work. NIce job on that Tee - looks perfect, and good to see everything working well. :NotWorthy:
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Many thanks guys.
Not quite at the end of the journey yet, but it's in sight...
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Congratulations Gary! That's a nice set up!
John
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Thank you John.
:ThumbsUp:
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Hi Gary, great to see the whole plant running as planned. You must be feeling very pleased.
Did it take much pumping to maintain the level in the boiler?
You are quite right to feel that condensate is better in the jar than spread though out your workshop where it can only cause harm. However, I do hope your workshop is well ventilated when you are running that burner.
To understand what that quantity of condensate means, it is necessary to understand what is happening in the plant, and hence why the condensate formed. More measurements are need to quantify things with more confidence, (I don’t think “exactly” is a relevant concept here), but we can do some basic calculations to give an idea of the magnitude of the quantities, which in turn will indicate which measurements are required if you want to go into more detail.
Initially you will have poured or pumped some cold water into the boiler. Possible 15 or 20 deg C, or since it is winter there, you may have decided to speed things up using water from a freshly boiled kettle. Then the heat from your burner heats things up. Initially, everything around the boiler, meaning it’s copper shell and tubes, external fittings etc. as well as the water. Once the boiler reaches steam temperature, the metal parts do not absorb more heat, and further heat goes into evaporating the water. The steam is then opened to the engine. Initially it looses some heat to the copper piping, which will result in some condensate forming, then it warms up the engine, even more condensate before it will run without spluttering, and finally your exhaust separator, where even more heat goes into the metal parts before the remaining steam goes up the stack to atmosphere.
Once the engine is running under roughly constant conditions, all those hot parts that are not really well insulated will continue to loose heat to the atmosphere, the engine will change some of the heat into work, a very small amount unfortunately, and of course, you will have to start pumping water through the coil in the separator into the boiler. The fresh water will absorb heat from the exhaust steam in the separator and of course cause more condensate. This last bit is the condensate that you might call “desirable yield”, so the most important when it comes to your question.
You might guess that to proceed further, it would be good to empty and perhaps measure the condensate soon after the engine starts running to determine how much was formed during warming up the system, then resume collecting in a second jar. Then it would be good to know how much fresh water you pumped into the boiler to maintain the level. Finally, it would be interesting to know the water temperature into and out of that coil in the separator. Of course, that might be way over the top for your interest, but to give you an idea of the magnitude of the numbers, we can calculate roughly how much heat was lost by that 100 ml of water in condensing from steam. From the steam tables assuming relatively low pressure, we can see that the enthalpy of dry saturated steam is about 2676 kJ/kg. If we assume it had cooled to say 80 C in the separator before run was finished, at this temperature, condensed water has an enthalpy of 250 kJ/kg, so we can estimate the heat lost by the steam to make that condensate was 2426 kJ. For 100 ml, approximately 0.1 kg, 242.6 kJ or 242600 J.
This is not a figure that would mean much to most of us, including me. However we can look up the specific heat of the copper, bronze and brass which was heated during your plant run time. My text book gives slightly different values for each metal, but for our purposes we can assume the average is about 400 J/kg. If this metal started at say 20 C and was heated to roughly 100 C, we can calculate that this was sufficient heat to raise about 7.7 kg through that temperature range. Now the boiler is directly heated by the burner, so we need to guess the piping plus engine plus separator, perhaps 2 kg max possibly only 1 kg. So we can see that heating up the cold metal does not explain all the condensate, indeed, probably only around 20% of it.
We are hoping that coil has heated feed water, so let’s see how much it would heat. Again let’s assume the water started at 20 and was heated to 80 in the coil. The steam is probably close to 100 but you need a temperature difference to cause heat transfer, and we have limited area. It would be interesting to measure the coil outlet water temperature, but let’s continue assuming 80 C.
The specific heat of water in that temperature range is 4184 J/kg, so our 242600 J would heat approximately 1 kg or 1 litre through (80-20 or) 60 deg. If 20% of the heat was used for warming up the metal, perhaps 800 ml of water. I wonder how much you actually pumped through the system. The condensate is not the same as consumed by the engine, of course. Most of the engine exhaust steam will be going up the stack, so you need several different water measurements to determine the engine steam.
Now either that will excite you, well interest you anyway, and you will want to make more measurements. Or perhaps you lost interest long ago and did not read this far. But I hope it will give those interested an idea of how thermodynamics can increase our understanding of how the steam plant works.
Looking forward to the next steps in the development of this plant. It’s a wonderful demonstration of what it is all about.
MJM460
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fine development of your steam plan; nice to follow Gary, congratuations !
Thanks for all these input MJM, I greatly appreciate your way to consider our hobby...
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Hi Zephyrin, I am glad you like it. I can’t add much in the machining area, still a beginner, still striving, but the theory is where I can make a little contribution to this hobby we all enjoy. I hope I get close to explaining things in a way that most can understand.
MJM460
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Many thanks, Gentlemen.
@ MJM - amazing exposition! When I was at school I never did my maths homework, and every single day I got into trouble for it. I guess that has stuck with me over the years, so to be honest I probably won't be making any calculations. I tend to go more by the general feel of things. However, even to me what you have written makes sense, particularly the point about the initial heatup producing much more condensate (from all parts of the plant) than when the plant is running hot.
Your first question reminded me of what I forgot to include in my prior post, which was that the plant seems to consume a lot less water now that the separator/preheater is in the system. I guess that means that the preheater is doing its job. Cerrtainly, the pipe coming away from the preheater coil was palpably warmer than the one going into it. To reiterate, my sense (albeit not very scientific) is that the engine ran slower but with more torque, and that overall significantly less pumping of water was required. There didn't seeem to be a great deal of steam coming out of the stack, though I guess it must have gone somewhere.
Yes, the kerosene burner does fume somewhat, but I found that keeping the workshop door open cleared it ok. I'm looking forward to trying the vapourising meths burner with this setup!
MJM - please feel free to continue posting on the science of things. Even if I am mathematically challlenged, it's still interesting and educational.
@ Zephyrin - thank you for your kind comments. It feels like I have been on a long journey since you explained to me how to grind off that leaky lump of silver solder at the end of one of the tubes on this boiler and resolder the join. That was advice and encouragement when it was most needed! Much appreciated...
And now, lagging the pipes. I have done one so far, and I admit it's not wonderfully neat (especially at the ends), but they will improve with practice.
First, a layer of amalgamating tape (thank you again MJM), cut into narrow strips the better to negotiate bends:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/848606.jpg)
Then a layer of string, held with super glue at each end:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/848605.jpg)
And finally, a layer of acrylic paint - brushed into the string straight from the tube, no water:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/848604.jpg)
Yes. Red.
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Great thread and can plot the progress. When did you actually start the boiler and engine project, i think this thread started when you had made the engine & boiler 4 months ago...
I have been 14 months on a similar journey and not had steam yet !
Great to see a video as well
Rob
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Hi Rob, and thanks for your comment.
I started with the boiler, which I began in the Spring of 2018, so similar timeframe perhaps.
These things can't be rushed, and life keeps getting in the way too!
Looking forward to seeing a thread on your project if you decide to start one.
gary
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Hi Gary, I am glad you found my explanation interesting and understandable. The maths is not for everyone, but I like to think that just knowing that the maths can be done, and relying only on good data for fluid properties and the basic laws of physics, is worthwhile knowledge. It is not magic, just the action of the basic laws of the universe. And our little steam plants demonstrate in an accessible manner so much of the physics.
I am glad you asked again about the engine power and torque. I gave it quite a bit of thought while writing yesterday’s post, then it slipped my mind. But not completely, I woke up thinking about it this morning, remembering that I had missed commenting. Strange how the memory works, or doesn’t, as the case may be.
Your plant does add a little length to the exhaust piping, but I don’t think enough extra resistance to easy see the effect. The separator has plenty of internal space for the steam to flow without significant resistance. So it is hard to see an explanation for your observations. But in my experience, observations are usually real, so it means we have to look harder for the explanation.
One thing we know is that your engine has now had a bit of running in, so might be spinning much more freely than it did at first. I am wondering if you actually let the boiler pressure rise quite a bit higher than the engine needs, then use the stop valve to throttle the steam to the engine. There are good reasons to do this, but let’s try and stay on topic.
It may well be running a bit slower than before, but I wonder if the throttle valve is adjusted differently than previously? However, if, as I am assuming, the boiler pressure is somewhat higher than needed by the unloaded engine, and possibly higher than for earlier tests, when you slow the engine, by holding the flywheel or similar means, there is less pressure drop through the valve (due to the lower steam velocity, so the engine sees more of the steam pressure, and hence produces more torque. Similarly, the oscillating engine valves are formed by the common area of two partly overlapping circles, usually until about half stroke, where they may be fully overlapping. At slower speed, there is more time for steam to flow into the cylinder, resulting in higher pressure on the face of the piston. More pressure means more torque. Of course if the throttle valve was fully open for each run that explanation evaporates. Similarly if the boiler pressure was higher than the earlier runs.
Another thought is that the engine is running much as earlier give or take a bit of variation in boiler pressure or throttle setting, but now with more experience you are observing things you previously did not notice. After all there is a lot of learning going on in those first runs of your first engine.
So keep looking and experimenting and see if you can pick up other factors which may offer a better explanation.
Regarding the observation of the quantity of steam from the stack, remember that dry steam is colourless, and the white mist we see and associate with steam is caused by light reflection on the minute water droplets in wet steam. If your separator is doing its job, those droplets should be coalescing on the inside walls of the vessel, leaving dry steam exiting the stack.
Sometimes there is a clear gap between the top of the stack and where steam starts visibility condensing. However with a lower velocity of air exiting the stack, there is a lot of air mixing which reduces the partial pressure of the water in the fluid exiting the stack, and this reduction in partial pressure significantly reduces the dew point temperature or condensing temperature, so that the exhaust stream becomes superheated, and so disappears as higher humidity as it mixes with more air. I suspect this is why you see less steam exiting the stack. Of course there may actually be less steam exiting, if as suggested earlier the engine is running freer and requiring less pressure, so that you have throttled the steam flow a bit to get a pleasing speed.
By providing some heat to the feedwater, the preheated reduces the energy necessary to raise the water to boiling point. Hence, if all else remains constant, particularly the burner fuel consumption, the boiler would operate at a slightly higher pressure. This would require more throttling to achieve a similar engine speed, and combined with the free running engine, would indicate a lower steam flow requirement. But I don’t know if the effect would be noticeable.
Not sure if there are some satisfactory explanations in those suggestions, but at least it should prompt some ideas of what to look for or measure in order to identify what is going on.
Looking forward to the next steps
MJM460
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Thanks for this MJM. You have very clear knowledge of all of this, and the way you describe it makes the processes apparent where they previously weren't - at least to me. Sorry that my steam plant is invading your sleep though!
To be honest, I'm not totally sure that I was doing anything different with the throttle. I may have been, but I think I had it pretty wide open most of the time. I will play around with this next time. It's also possible that I'm imagining things - my impressions are very subjective after all, and it's been a while since the last run before this one.
There is however another variable not related to steam or heat, which is the tightness of the retaining spring holding the cylinder against the port block. I think I had it tighter this last time for most of the run, which could account for the slower speed, and - given your interesting point about the longer steam admission through the overlapping ports could - I guess - increase the torque too (though it would also be working against increased friction from the spring, so that could mitigate the increase I suppose). So many parameters adding layers to the complexity in an apparently simple system!
One thing that has always happened with this plant is that I can let the pressure build up quite high initially (about 50 psi on the gauge, probably - as you say - much higher than the engine needs), then when I open the steam out valve it goes like a demon for about 30 seconds with clouds of wet steam around the engine, then the not very acccurate small gauge drops back down to the peg (i.e. a false reading of zero) but the engine runs for ages as described. Maybe I should try to control that by not opening the valve so wide at the start...
The displacement lubricator seems to work well. I'm not sure I had the needle valve open wide enough, but there was definitely some oil getting through. I can play around with that. It's all a learning curve...
As for the exhaust steam - certainly what steam there was was invisible, i.e. dry, so the separator must be doing its job. Very pleasing that that part of the build was a success. But what struck me was that I held a tiny scrap of tissue paper over the stack and it hardly fluttered at all. This was why I said that there seemed to be almost nothing coming out of the stack. I wasn't necessairly expecting visible wet steam, but I was expecting more of something :). I'll look more closely at this next time, which will be after the pipes are all lagged, and I reckon I'll have a go with the pressurized meths burner.
But the thing is, it runs! None of the issues under discussion are worrying me, but yes it's interesting to learn a bit about the reasons why things happen the way they do. And your knowledge of them is making this thread into a resource which even others much more experienced than me will find informative.
:ThumbsUp:
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Hi Gary, thank you. I think you probably were right in the button remembering that you had tightened the spring. That is a likely explanation for some difference in performance.
The spring holds the cylinder port face against the port face on the standard. On one hand a tight spring seals against steam leakage across the port face to atmosphere, but on the other hand, a tighter adjustment increases friction as the cylinder oscillates. The steam pressure at the port in the standard is trying to push the cylinder away from the stand, so leakage will be high if the spring is loose.
Running unloaded, all the work produced by the engine is used purely to overcome friction. So if you increase friction by tightening the spring, that increases the load on the engine, which will slow it down. With luck and a well aligned port face with the cylinder pivot truly at right angles to the face, it will reduce that steam leakage, making more available to be converted to work by the engine, and preferably more than the extra power lost by the extra friction. Room for experiment to find the best adjustment.
By the way, in trying to explain your observed increase in torque, I did overlook the very obvious. The torque needed to overcome friction in the engine is relatively constant, regardless of speed. So if the engine is overcoming friction, plus working against something rubbing on the flywheel, it is definitely producing more torque.
If you did not adjust the burner, there is no extra power available, and as power equals torque times rotational speed, more torque, same power means less speed. However, that also means that while the torque to overcome friction does not change much, the power lost to friction is less at lower speed.
Now the power is not necessarily exactly constant through all this as, with different steam velocity etc. the efficiency probably changes a bit. But with no burner adjustment, it can never be more, and most likely less.
But at the end of the day we still have conservation of energy, and conservation of energy is one of the fundamental laws of physics. It is neither created or destroyed, just changed to different forms. Like your car keys, it does not vanish when you lose it, it just takes more effort to find out where it has gone.
Lubricator are interesting things. I often wonder if the needle valve does much to change to rate at which oil escapes to the engine, another area with room for more experimentation, but I suspect if you fill it before each run and drain the condensate afterwards, the engine will have enough oil, whether it is injected quickly or slowly. Some oil is always better than no oil and all those little Mamod engines and similar had no lubricators, only what the owner dropped around the port face before and possibly during running. Wet steam from a simple boiler probably helps a little, but if not oiled and a lot of running they probably showed a lot of wear. So I think any oil will look after your engine, preferably try and find some proper steam oil, it sticks to your boots better, but use what you can find.
Longer admission time due to the engine running more slowly allows more steam to enter the cylinder while the ports are open just as far as they were when the engine ran faster. More steam in the cylinder means more pressure at the piston face, which gives more torque. That is why large valve ports and large steam passages in the block is important.
I mentioned that there are good reasons to run the boiler at higher pressure, even though you don’t need it to run the engine. At higher pressure the volume of the steam produced is smaller, so it rises to the surface less vigorously, so it carries over less water to the steam outlet, thus delivering drier steam to the engine. However, when you open the stop valve, just open it enough to run the engine at the speed you want and keep the boiler pressure higher. The small volume of the high pressure steam increases as the pressure drops in passing through the only slightly open throttle valve. Only a very small loss in boiler efficiency, as the higher boiling temperature means slightly less heat transfer from the flue gas. The boiler exhaust gas will be a bit higher temperature. But the chimney is a generous size so the stack velocity might be quite low. Try if a longer ribbon of tissue taped to a bamboo stick to keep your fingers out of the hot gas is more sensitive. And whether you can see a difference between when the engine is running and not.
So much to learn from such a deceptively simple looking plant. But it all applies when you go on to build something more complex or larger. And all part of the fun.
And above all, as you say, it runs. Always an exciting achievement.
MJM460
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Have been very busy with work...
MJM - yes, interesting. Increase the friction slowing down the speed which lets more steam in which counters the loss through friction... parameters working against each other means that there is a sweet spot somewhere in there waiting to be discovered.
Interesting that you suggest that I only let enough steam out of the boiler at pressure to run the engine. I had come to that conclusion myself, and will try it next time. I have up to now tended to let rip with the steam from the outset - probably why the pressure drops so quickly.
Another thing I'm going to do is put some graphite yarn in the groove in the piston. I machined the groove shortly after I made the piston but it has never been used. Definitely worth a try.
On lubrication - I do have steam oil - a big bottle of it that someone gave me with a lathe I bought. That's what I have been using. It did seem to me that not a great deal was getting through, but that said I did drain a reasonable amount of water from the lubricator post-run so clearly it was working. I'll try opening the needle valve right up and see if it makes a difference...
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Hi Gary,
Basically, if the boiler is operating at higher pressure and the steam outlet restricted by the throttle valve, then slowing the engine means less volume of steam to the engine. The pressure drop cross that throttle valve will reduce at lower flow rate. So the piston will see a higher effective pressure, so produce more torque.
If the increase in torque is enough, the engine keeps running at a slower speed where the torque produced is just enough to overcome the friction. You might wonder if this will really produce enough extra torque. Well it did, because you reported that the engine continued running at a lower speed. If the torque increase was not enough, the engine would stall/stop. The engine finds that sweet spot on its own unless you interfere by changing something.
It’s the rotational equivalent of Newton’s laws about a body continuing in a state of uniform motion unless acted on by an external force.
In rotational systems, a spinning body continues to spin at a uniform rate unless acted on by an external torque.
In each case, the external force or torque is the resultant from adding all the torques or forces as vectors to find a single equivalent action.
Of course, having the engine run at constant speed is not the same as the whole plant being in equilibrium. With the engine taking less steam, the boiler pressure will increase, starting another chain of actions. The higher pressure means higher boiling temperature which reduces the temperature difference driving heat transfer from the flue gas, so the flue gas at the stack is hotter, taking the excess heat to the atmosphere.
If this is enough, the boiler finds a new steady pressure, if not, the pressure continues to rise until the safety valve lifts. Or the operator turns down the burner a bit.
I hope that is not all too confusing.
MJM460
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Well, I had to study it a bit but I got there. Yes, there's a heck of a lot going on, isn't there?
And the whole universe is like that... :o
I will certainly try running it with much less steam from the outset next time.
Now, at the other end of the steam spectrum from hard science: I had a dream a couple of weeks ago that the base board for the plant was supported by four ball and claw feet, one at each corner, the claw being made of bronze and the ball of glass. I like to follow dreams (well, some of them anyway) so on to the internet I went and sure enough, ball and claw feet with a glass ball do exist. There were quite a few on ebay.com, and all appeared to be antiques from the USA for about $50 a set and the same again for postage to here in Britland. In other words, a bit more than I fancied spending on them.
However, on ebay.co.uk I found (and bought) these for a much lower price:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/849797.jpg)
'Lion's paw' feet, possibly from a clock originally. Each one is 8cm long. They are chunky and quite heavy, appearing as they do to be made of cast iron with a copper-coloured plating on them. The seller thought they may be French.
Totally over the top! Going full Steamgoth...
:pinkelephant:
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Totally over the top! Going full Steamgoth...
:pinkelephant:
I love it!
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:ThumbsUp:
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Too cool! :ThumbsUp:
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I'm betting you're the first on on your street to have a set of these! :thinking:
Jim
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Thanks Guys.
@ Jim - probably, but soon they'll all have them...
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My plan had been to hook up a tiny generating set and light to the plant as a finishing touch, even though I'm not quite ready for finishing touches. However, I ended up disheartened by unsuccessful tinkerings with toy motors and LED's. Electrics is not my thing.
So, instead, I have just taken a trip back to my childhood and ordered this:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/849921.jpg)
It was the cheapest one available on ebay UK, despite it being in new condition. But what really drew me to it was the fact that it is not painted in the traditional Mamod pale green, but is of their more recent blue colour scheme. I like this because I plan to paint it to suit the plant, and to get rid of old-school Mamod green would be too excruciating for words, while removing that blue will pain me not at all.
So hopefully with this addition the plant will be able to do real, useful work, such as sharpening pins. Which I'll be able to use to jab myself with to make sure I'm not dreaming again...
See? A real machine - not a model at all...
;)
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Great idea - I look forward to seeing that run. Fun little grinding wheel.
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:Lol: Fun post.
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Cheers guys!
8) :ThumbsUp: :ThumbsUp:
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The feet are now screwed to the bottom corners of the base board, and a profiled trim of softwood beading has been cut and shaped ready to be attached to the board using brass slot-head screws. Since this picture was taken the trim has been removed and given a further tidy up and is currently being given a few coats of Danish oil which will bring out the figure and give it a nice golden sheen to contrast nicely with the dark varnish on the board:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/850369.jpg)
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Following a conversation with MJM460 above I refrained from opening the main steam valve right up at the start of the run. This seemed to make quite a difference, enabling me as it did to keep the needle off the peg (at about 20 psi) for a significant length of time. The newly lagged pipes may have helped too.
I was also able to test the Mamod grinding wheel:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/851272.jpg)
Unfortunately, in my enthusiasm I forgot to refit the tiny grubscrew on the grinder's drive pulley after fitting the provisional rubber band belt, so the pulley was spinning on its shaft. However, even with that rather glaring omission the grinding wheels were flying round with a fair bit of torque. With the pulley held tight to the shaft, this contraption will perform wonders, I tell you.
In fact to be honest I later dropped the grubscrew on the shop floor TWICE and somehow managed to find it both times, despite the floor being far from detritus-free at this point in time. And it is one very small grub screw...
The next step is to cannibalize and repaint the grinder and mount it on a cylindrical base of aluminium. Also, I have ordered a selection of different lengths of 1mm square section drive belts of the kind used in audio cassette players. Hopefully one of these of the right length will work nicely and look better than a rubber band.
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In fact to be honest I later dropped the grubscrew on the shop floor TWICE and somehow managed to find it both times, despite the floor being far from detritus-free at this point in time. And it is one very small grub screw...
That's too lucky. In my life, things always seem to balance out over time. So be careful. ;D
(I don't mean to jinx you but stories like that usually end with "not to be seen ever more".)
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In fact to be honest I later dropped the grubscrew on the shop floor TWICE and somehow managed to find it both times, despite the floor being far from detritus-free at this point in time. And it is one very small grub screw...
That's too lucky. In my life, things always seem to balance out over time. So be careful. ;D
(I don't mean to jinx you but stories like that usually end with "not to be seen ever more".)
Wow - Gary is faster than a Shop Gnome! Bet you heard some grumbling from under the cabinet...
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Guys.
I know! And the next time I drop it will be the third...
And it will turn out that Mamod use a unique and esoteric thread and I'll have to faff around cross-drilling and re-tapping that miniscule pulley!
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Decided to have another go at running the plant on the pressurized alcohol burner a couple of says ago. Unfortunately I overestimated the amount of alcohol required in the preheating cup. This caused a minor inferno under the boiler which melted the end of the rubber supply pipe inside its braided wire sheathing, blocking the pipe. So, I got rid of the pipe and was left with this:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/851479.jpg)
My idea is to replace the pipe with copper tubing which I will silver solder on to the two spigots (well, I'll call them spigots) that can be seen in the picture. I have two sizes of copper tubing - one too big and the other too small. I think I'll use a drill to widen the end of the narrower tube rather than turn down the spigots.
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Do you have a way to fasten the tank and burner down to a common base or each other, so you can move it without stressing the copper tube too much?
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Good question Chris!
I have been mulling that very point, i.e. how to keep things stable to protect the tube.
No definite plan as yet, but will keep on it.
Cheers...
:ThumbsUp:
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Do you have a way to fasten the tank and burner down to a common base or each other, so you can move it without stressing the copper tube too much?
One thing I will have to do in any case is put a union in the copper tube as it will be impossible to shoehorn that burner in under the boiler with a long tube attached to it. There is little room to spare in there. So I'll have to put the burner in place then connect it up. That will help, but I reckon something of the sort you are suggesting would make it better still.
:ThumbsUp:
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:cheers:
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From vintage Brit steam toy...
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/851699.jpg)
... to the Emperor Dalek of tiny grinders.
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Ha - love the Dalek reference. I was a huge Dr. Who fan at one time, but I digress. Nice job on that little grinder, looks much better now!
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Ex-Bur-iate!
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Thanks guys.
Good to know there are some fellow Whovians on the forum.
I go right back to the William Hartnell days... but Jodie Whitaker is fab too :LittleAngel:
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Workshop in a time machine - explains a lot of progress... :Lol:
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So that's how you do it...!
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So that's how you do it...!
Helps to have Galifreyan elves...
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Workshop in a time machine - explains a lot of progress... :Lol:
Wonder if it's also bigger inside that outside :noidea:
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Mine is the opposite - huge presence in the back yard, but inside no room to move.
It's a Reverse-dimensional Tardis Workstation (RDTW).
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It's a Reverse-dimensional Tardis Workstation (RDTW).
:lolb: :lolb: - that I really can relate to - I work in such an environment professionally.
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Commiserations, Admiral. However, it's better than being lost in the trans-dimensional flux. Or being incarcerated by the Judoon on a prison asteroid until the 2021 season airs....
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Forgive this shameless digression.
Just when I was about to put the final finishing touches on to the steam plant, this fell into my lap (though not literally, I'm glad to say):
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/852864.jpg)
So I had to get a big lump of oak to mount it on. And a ladder to slide it up to get it on to the stand.
Then something had to be done about about that relentless blue:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/852863.jpg)
And if you have an anvil you need one of these:
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/852862.jpg)
Once it's all done I'll finish the plant and then move on to my next engine...
State of my shop at the moment though. For shame...
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An anvil fell into your yard (or lap, whatever). I'd check for Wile E Coyote on your roof. And stop reading the Acme catalog, maybe they sent you a complementary anvil to lob at roadrunners! :Lol: The anvil I use is about the size of the rectangular bit at the base of the horn on yours!
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:)
Yeah, this thing is big - two hundred and sixty-something pounds.
I have no blacksmithing skills that I am aware of but I'm looking forward to having a go...
:Mad:
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Well, despite having been pulled away from this project by one thing and another(!), I am now calling the plant complete. All I have to do is put the finishing touches to the alcohol burner.
Meanwhile, however, here's the celebratory video:
https://www.youtube.com/watch?v=rmSF6UXGunI
Hope you are all safe and keeping well in these challenging times.
gary
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Well done Gary, and beautifully presented. That’s one to be really proud of.
I have enjoyed following your progress along the way. It has been a big learning curve for you, and you succeeded at every challenge. And your artistic ability and imagination shows through, giving the whole model a unique character.
I quite like the look of the red pipe insulation.
So now, what is the next project?
MJM460
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Thank you MJM.
A learning curve it certainly has been, and it would have been much harder without the invaluable input I had from you and various other mentors on this forum. :LittleAngel:
The next project? Well, there's the flash steam generator, although that's really a kind of ongoing side project to accompany others. But I have a notion of building an engine to run on it, which is likely I think to be a scaled-up version of Stan Bray's 'Clarence' 'clapper valve' engine, which I understand to be a simple uniflow design. That's my current plan, anyway...