Biopowered - vegetable oil and biodiesel forum
Biodiesel => Biodiesel equipment => Topic started by: Julian on August 25, 2014, 08:56:13 PM
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Been playing today.
I was quite disappointed that the multitube condenser I posted on the VOD a few years back came to nothing due to the cost of suitable tube, but the tube plate idea has been swimming around in my head ever since.
Now with the 3D printer (yes, I can hear the groans and Tony muttering "when you have a hammer ..."), but I think these ideas may be worth persuing.
Normally I'd advance the design much further, I have many ideas filed in the aging cranium, but as it's a bit quiet I though I'd post a couple of test pieces and see if any one comes up with anything. I'm thinking around a rain water down pipe as the body, plumber's delights for the tubes and plenums top and bottom.
One major issue with printed plastic is it's low melting point. No an issue for the bottom plate and I'm having thoughts on insulating the top with thinned silicone calking or Oogoo (Google it!) both of which I've been playing with recently.
First idea is for the tube plate to body joint. Printed plastic with a recess filled with silicone, top and bottom clamped with studding. Could possibly press the body into the silicone whilst it's still wet.
(http://www.palmergroup.co.uk/Bio/Multitube condenser/Condenser test 1.JPG)
Second idea was to use an O ring. Nitrile has excellent resistance to methanol. This ring was from one of those red boxes containing various sizes. Say it myself the fit is amazing and would certainly seal perfectly for the duty we want.
(http://www.palmergroup.co.uk/Bio/Multitube condenser/Condenser test 2.JPG)
(http://www.palmergroup.co.uk/Bio/Multitube condenser/Condenser test 2-2.JPG)
If the design can be economically printed I'd be happy to consider producing it for members if there's a demand.
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Interesting.
One situation where temperature is not an issue is drywashing.
At the moment many of us use one 110mm drainpipe, which has two problems:
- first flush has to be recirculated until the dust is re-trapped by the wood shavings
- it's always the inlet bit that clogs with soap first, so changing the lot wastes some of the potential of the shavings near the outlet
I've long thought some solution with four smaller bore (43mm?) waste pipes in series would be a good solution, you could slowly cycle them taking turns as to which one is on inlet duty, and when replacing the sawdust only do it to the inlet tube so dust is trapped by the three downstream.
I've no idea how best to implement this, but a 3d printer would potentially change the landscape of possibilities.
Do we know how well the plastic resists bio long term? Some of the plastic parts on my drywash tower have split after a couple of years of use (I think they may be black ABS).
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That sound like a good project ... do you want to have a think and sketch up some ideas just a scan of a fag packet design will do to start. Push fit waste pipe fittings use O rings, just need to make sure they don't pop off under pressure!
I've tried PLA with methanol and it seems OK short term... perhaps I should do some long term tests.
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More thoughts ... would fire cement be a suitable, moldable insulator for the top tube plate?
And would heat conducted along the tubes be a problem for the plastic?
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It's a shame K.H's clamp-top drywash tower failed under pressure. Still, it was an interesting experiment. I'll have a think Julian. :)
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I wonder if the second test piece could be modified to take components from a push fit plumbing fitting?
That would be good for the water connections, condense and vapour outlets ... more playing tomorrow me thinks, (provided my new filament arrives).
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My tower is leaking like a sieve. I think it's down to the gasket under the screw cap/s.
The solution I came up with was to put it inside my second settling tank ... it can leak all it likes now!
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I wonder if the second test piece could be modified to take components from a push fit plumbing fitting?
That would be good for the water connections, condense and vapour outlets ... more playing tomorrow me thinks, (provided my new filament arrives).
That sounds like an excellent plan. Push fit is pretty clever stuff.
My tower is leaking like a sieve. I think it's down to the gasket under the screw cap/s.
The solution I came up with was to put it inside my second settling tank ... it can leak all it likes now!
Mine sits in a bucket I have to periodically empty...
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Just pulled a Speed fit fitting apart. Incorporating it's parts looks completely doable.
Screwfix do 5 off 15mm Ts for 10 quid, so circa 67p per connection!
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He, he, Plumbcenter do the collets and O rings as spares for 37p and you get the insert O ring too! Just need the backing ring which is easy to print.
(http://www.plumbcenter.co.uk/wcsstore7.00.00.749/ExtendedSitesCatalogAssetStore/images/products/AssetPush/wol-web-proof-pdp-w/std.lang.all/77/16/517716_wpdp.jpg)
http://www.plumbcenter.co.uk/en/speedfit-15mm-epdm-o-ring-15-epr-62944?top_category=18233
and 22mm at 57p ...
http://www.plumbcenter.co.uk/en/plumbing/fittings/plastic-fittings/jg-speedfit-plastic-fittings/jg-speedfit-22mm-epdm-o-ring-22-epr-each-62916
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Eminently doable then :)
EPDM would turn to squishy mush in short order, though I expect they are sizes readily available in Viton/Nitrile.
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Eminently doable then :)
EPDM would turn to squishy mush in short order, though I expect they are sizes readily available in Viton/Nitrile.
EPDM is fine with methanol I believe. I found this http://www.biodiesel.org/docs/ffs-performace_usage/materials-compatibility.pdf?sfvrsn=4 which states it's "fair" and "usually OK for static seal" have you had bad experiences with EPDM?
If fact there's quite a lot of good info in that pdf, it might be worth plagiarising it for the wiki!
Nitrle O rings the same size as my test piece, (the Speed fit one is a bigger cross section, but it will make little difference to the cost) are about 17p in reasonable numbers. Viton a little more, so not really an issue. The critical bit is the collet which would be impossible to print.
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Just tried the little flange with the silicone filled groove on a bit of 22mm pipe and that too seem to work well.
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There you go Tony ... a 40mm waste to 15mm push-in fitting in section.
(http://www.palmergroup.co.uk/Bio/Multitube condenser/40mm - 15mm push-in section.JPG)
Didn't have any 40mm pipe just fittings (which is where the O ring came from), but the 15mm end seems to work reasonably well ... might need to increase the diameter of the O ring housing a shade, but the collet mechanism appears to hold well.
As I type I noticed I made the groove for the big O ring too deep so that will need changing too.
As for fixing it to the 40mm pipe, I had thoughts on a double split clamp with serrated teeth grafted on to 40mm end with a couple of bolts to pull it up tight on the pipe.
Is this along the line you're thinking?
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For those interested, here's a graphic ...
(http://www.palmergroup.co.uk/Bio/Multitube condenser/40mm - 15 push fit section.jpg)
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That is very cool. With the seals I was thinking more of biodiesel interaction than methanol. Though in hindsight I think what I've seen turn to slush was natural rubber and EPDM just swelled.
Certainly a clampable fitment would allow multi-tube drywash use :)
I'm imagining a rack of horizontal tubes resting on hooks, or vertical array (possibly better) where you just un-plumb the one you want to replace, remove the bolts from the fitting at one end and expel the tube of spent drywash material (perhaps using compressed air?).
The ideal fitting might have some kind of ABS mesh integrated into the end to retain the drywash material? And perhaps a 90 degree in the end to make piping to the next tube in the array easy.
You could be onto a saleable eBay product idea with that :)
My only concern would be whether any of the fittings could pop off under pressure. But it works for water for pushfit - it's just the clamp to the 40mm tube that might be an issue.
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In Koi ponds most people use a small self tapper through the outer connector into the 40 mm pipe when after the pump, stops it blowing off and no leaks either.
I didn't fully understand what you were describing earlier, but that connectors looking pretty good.
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Interesting. I don't suppose you've got a link to a thread or photo that shows this arrangement?
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Not got mine anymore but will try and get a photo.
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I did think of a 90° bend at the top, but I suspect the print will be stronger and more accurate if it's concentric.
How important is it that the bio flows up the tower? I had thoughts of a double cap arrangement with an integral connection, where it goes up one tube and down the next. You'd only need two push fit connectors that way, one at each end of the array.
Can anyone come up with an idea for a mesh? Shower mixers usually have filters molded into a rubber washer, but they are only 15mm diameter.
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Im not 100% sure i follow what your aim is, but, when ive considered this type of thing before, i planned on using these -
(http://cdn.toolstation.com/images/130125-UK/images/library/stock/webbig/25751.jpg?rand=126751169)
which could be drilled in the center (theyre 110mm soil pipe) for a standard tank connector, with appropriate flat washer, and then the screw thread on the 110mm could be sealed with a whole load of PTFE tape (2 rolls if need be - only 50p or somthing)
My inline immersion heater has no flat washer in it, as it was always problematic. Mid batch once, it failed fully, and i sealed it with the only thing i had (ptfe tape) and its never leaked a drop since.
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With the 110mm pipe it's better to have solvent weld end caps that don't reduce the opening size at the ends, so it's easier to fill and empty.
On Julian's end fitting idea, I'd have thought that the integrated twin-connector between tubes would run the risk of excess mechanical loading given the leverage of the pipes during changeover operations.
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110mm pipe is what I'm using at the moment, it leaks like a sieve and is rather unwieldy.
A bank of tubes could slot into a frame (plywood with a lump of 4x2 screwed top and bottom) to stop the ends popping off. You could make a drip tray at the bottom to catch any spills.
Good point about the leaverage on the fittings, Tony ... perhaps better to connect with a flexible hose, but experience shows they leak too.
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(http://i1157.photobucket.com/albums/p594/miketheknite/Bio/imagejpg1-1.jpg) (http://s1157.photobucket.com/user/miketheknite/media/Bio/imagejpg1-1.jpg.html)
I couldn't find a photo but hope this helps.
When the 40mm pipe is pushed into position drill and screw a self tapper where the arrow is. I used this arrangement on my 1000gph return through a uv filter so that I could remove it if necessary.
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I feel as if im missing somthing here!
I understand that some of you have used 110mm soil pipe before, and that it has leaked - hence looking for a solution.
Im not understanding where its leaking from though?
I mentioned using screw top solvent weld fittings for the ends, with ptfe on the threads, and tank connectors. Im pretty sure these would not leak, so im thinking the problems are the (in the case of a condenser) the coolant pipes?
Cant these just be done in the same way? With solvent weld tees, solvent weld blanking caps, and then tank connectors, with appropriate flat washers?
I know waste pipe push fit fittings fall apart with bio, so these cant be used, but im sure its all possible with ptfe, solvent weld, and flat washers?
So i feel im missing somthing!
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No I don't think so. I started out suggesting ideas I'd had to make a multitube condenser using the printer.
Tony suggested making bits for a dry wash tower as a it ran at ambient temperature and thought multiple tubes of a smaller diameter might be easier to replenish ... hence the suggestion of waste pipe.
Someone along the line came up with using 15mm push fit fittings (I think it was me) and that seemed like a fun thing to make on the printer, so I had a bash and combined it with Tony's waste pipe idea ... see photos.
The thought then was that push fit wastes would pop out under pressure so I thought of a clamp arrangement and Manfred suggested a screw through the fitting.
You suggested using solventweld which would work, but would need a mesh fitted to retain the media.
I'm still thinking about designs for a multitube condenser.
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Two (three) ideas for mesh (which could even be combined)
a) you get fittings for soil and vent to go at the top of the vent stack to stop birds etc. falling down. i suspect theyre only availible in female fitting, but one could possibly be slitted and compressed.
b) in aquarium canister filters, a block of foam would often be at the base to stop the media falling through. it wasnt normal, upolstery style foam, but a rougher, tougher foam. may or may not be bio stable.
c) also in aquariums you had this wadding stuff that you could use for the same, or similar. did not compact when it got wet like other wadding would.
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I used old felt carpet underlay in my 110mm dia tower. Seems to work OK.
I think I used a sheet of plastic with holes and some studding legs to hold it in place.
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Back to the condenser ... I've spent last night drawing the condenser hot end. Thought I'd try printing it this morning but the file was all screwed up when transfered to the print program. So I've spent a large part of today trying to sort it out. I think I've got it sorted but it's too late to print now ... estimated print time over 9 hrs!!
Anyway, this is the design so far ...
(http://www.palmergroup.co.uk/Bio/Multitube condenser/Condenser hot end top.jpg)
(http://www.palmergroup.co.uk/Bio/Multitube condenser/Condenser hot end bottom.jpg)
The plan is, once the tubes are in place and protruding through the tube plate, fire cement or anything more suitable will be pored into the recess and a tin can top section settled in the cement. A big bead of silicone can then be run between the printed adapter and the can, well, that's the theory!
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The only disappointing thing about the free Sketchup is the way it draws circles or should I say polygons.
Surely the integrity of an O ring depends on a precise fit.
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I'm sure you can alter the number of sides for a circle (if that's not a contradiction!) somewhere in the program.
An O ring, to the best of my knowledge, seals because it tries to extrude its way out of its housing, so it should deform to conform to the polygon shape.