Biopowered - vegetable oil and biodiesel forum
Biodiesel => Biodiesel equipment => Topic started by: Julian on October 10, 2013, 12:54:21 PM
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This video was flagged up either on here or the VOD a while back ... http://www.youtube.com/watch?v=Abw3dG0SB0g
They don't show a finished product, and I have my doubts they would get complete conversion in one pass.
I know ultrasonics are used in some commercial processes, which I believe creates cavitation, but suitable transducers are ferociously expensive.
There are many ways to mechanically create cavitation but has anybody had any thoughts on using cavitation to aid processing on an existing rig?
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Well thanks to Mark I have a three phase gear pump, and I've got a VFD to drive it, just need to find the time to give it a whirl!
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looks interesting. wonder if a electric PSP would work.? cheap enough on fleabay to be worth a try.
i have seen this system working and producing bio diesel when i was in cambridge. never got around to building one though. i still have all the bits around somewhere.
http://onlinelibrary.wiley.com/doi/10.1002/jctb.782/abstract;jsessionid=88770DF91FDABA07763ACFF0BA20CC3E.f01t04?deniedAccessCustomisedMessage=&userIsAuthenticated=false
As that was filmed in texas in may i suspect the ambient temperature was quite high. someone will look it up. austin texas may 2009. i have a small gear pump i got for my centrifuge. still have to marry it to the motor. should work just as well for this.
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OK, someone's got to ask ... PSP?
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I was thinking of a modified centrifugal pump.
Many years ago I was involved in testing adding water to ships fuel by creating an emulsion. The device doing the mixing was, for all intents and purposes, a modified pump, designed by one of the universities.
The impeller (although it claimed not to pump) was like an enclosed centrifugal jobbie, with serrations around it's circumference, running very close to the body (can't remember if the body was serrated, but it would make sense if it were).
The claim was that this created cavitation to emulsify the water/fuel mix. Having done a little reading on cavitation, centrifugal pumps suffer cavitation if the cutwater is too close to the impeller, so the the theory would seem to be sound.
I've been toying with the idea of a winter project modifying a centrifugal pump, but if you chaps are that close to a pumped orifice system I may hold back to see the results.
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I think he is wrong..........
The mixture doesn't become bio because of the pressure drop, or cavitation.
The mix becomes bio, because of what the gears are doing to it in the gear pump. The pressure is a factor in this. I think he would get the same results if he took the cavitation piece, off altogether.
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I don't know whether this is relavent or not but my plant creates cavitation all the time when running....at the venturi. I know of another producer as well who is affected by this. Could this be an advantage in bio production?
Currently I eliminate it by opening the vent slightly to allow a bit of air to be drawn into into the venturi during ops.
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I don't know whether this is relavent or not but my plant creates cavitation all the time when running....at the venturi. I know of another producer as well who is affected by this. Could this be an advantage in bio production?
Currently I eliminate it by opening the vent slightly to allow a bit of air to be drawn into into the venturi during ops.
Interesting ... how do you know cavitation is taking place?
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I think he is wrong..........
The mixture doesn't become bio because of the pressure drop, or cavitation.
The mix becomes bio, because of what the gears are doing to it in the gear pump. The pressure is a factor in this. I think he would get the same results if he took the cavitation piece, off altogether.
A gear pump is actually quite gentle on a fluid ... in essence it takes a slug of liquid and pushes it through a cavity. A centrifugal pump creates far more shear and turbulence.
Cavitation creates voids which collapse, firing a jet of liquid at very high speed and very high temperature, all be it for a couple of milliseconds, but it's this action which is claimed to create the conversion.
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psp power steering pump.
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A gear pump is actually quite gentle on a fluid ... in essence it takes a slug of liquid and pushes it through a cavity. A centrifugal pump creates far more shear and turbulence.
Cavitation creates voids which collapse, firing a jet of liquid at very high speed and very high temperature, all be it for a couple of milliseconds, but it's this action which is claimed to create the conversion.
I see what you mean. I guess they must have done their homework anyway.
I agree that there must be a better way of inducing cavitation than just effectively spraying it at high (ish) pressure, if that is the essential bit of the equation.
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I don't know whether this is relavent or not but my plant creates cavitation all the time when running....at the venturi. I know of another producer as well who is affected by this. Could this be an advantage in bio production?
Currently I eliminate it by opening the vent slightly to allow a bit of air to be drawn into into the venturi during ops.
Interesting ... how do you know cavitation is taking place?
I think it was Tony that identified what was going on. The noise is incredable as the cavitation takes place at the out put side of the venturi. RichardP also has this phenomena.
I figured that I needed to eliminate it and the best way for me was by opening up the vent to the venturi ever so slightly. I suppose that prolonged exposure to it could cause issues in the venturi depending on where the void collapse takes place.
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I'm still not entirely sure i understand this. How can cavitation be induced under pressure, or by spraying?
Surely it needs something like a vacuum being created.
Wouldn't it be easier to induce cavitation by suction?
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I'm still not entirely sure i understand this. How can cavitation be induced under pressure, or by spraying?
Surely it needs something like a vacuum being created.
Wouldn't it be easier to induce cavitation by suction?
It's not just pressure, it's a sudden change of pressure which creates, not a bubble, but a void. The void is unsustainable and collapses with the effects described above.
This explains diagrammatically ...
(http://eswt.net/wp-content/uploads/2011/10/cavitation.gif)
An easy way to create cavitation is indeed on the suction of a pump. If you throttle a valve on the suction, most pumps will cavitate, but it doesn't do the pump much good ...
(http://www.processindustryforum.com/articles/UploadedImages/Cavitation%20damage%20pump%20impeller.jpg)
Or on a boats propeller ...
(http://www.olds.com.au/marine/cavitation_damage1.jpg)
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I don't know whether this is relavent or not but my plant creates cavitation all the time when running....at the venturi. I know of another producer as well who is affected by this. Could this be an advantage in bio production?
Currently I eliminate it by opening the vent slightly to allow a bit of air to be drawn into into the venturi during ops.
If the video is to be believed, yes.
I can't remember your plant exactly, have you got a high capacity pump? Is the venturi matched to the pump or is it under sized? Possibly smoothing the throat may help, so there's not quite such a sharp change of profile.
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The pump is an 80lt Lowara...lovely pump it is...and the venturi is matched to it. A 9.3mm throat if I rememeber correctly.
The intersection is a sharp angle. I suppose I could round it off and see if it makes a difference.
Did you round off the intersection in your venturi Julian? Are you still on a cast one or have you moved to a machined jobbie?
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The pump is an 80lt Lowara...lovely pump it is...and the venturi is matched to it. A 9.3mm throat if I rememeber correctly.
The intersection is a sharp angle. I suppose I could round it off and see if it makes a difference.
Did you round off the intersection in your venturi Julian? Are you still on a cast one or have you moved to a machined jobbie?
As a matter of interest Nige I always take the sharp edge off at the intersection of the two cones.
Open the throat on your venturi to 9.5mm and round the edges.
One of our number used to work on the design of very fast racing cars and knows a thing or two about air and liquid flows.
Anyway he's put some info into his poota and it's spat out a new profile, not vastly different just a couple of subtle changes. I'm gona make one and see if there's any improvement on performance over one of me standard venturis.
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The pump is an 80lt Lowara...lovely pump it is...and the venturi is matched to it. A 9.3mm throat if I rememeber correctly.
The intersection is a sharp angle. I suppose I could round it off and see if it makes a difference.
Did you round off the intersection in your venturi Julian? Are you still on a cast one or have you moved to a machined jobbie?
As a matter of interest Nige I always take the sharp edge off at the intersection of the two cones.
Open the throat on your venturi to 9.5mm and round the edges.
One of our number used to work on the design of very fast racing cars and knows a thing or two about air and liquid flows.
Anyway he's put some info into his poota and it's spat out a new profile, not vastly different just a couple of subtle changes. I'm gona make one and see if there's any improvement on performance over one of me standard venturis.
I wonder if this mystery member can come up with a devise to create cavitation?
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The pump is an 80lt Lowara...lovely pump it is...and the venturi is matched to it. A 9.3mm throat if I rememeber correctly.
The intersection is a sharp angle. I suppose I could round it off and see if it makes a difference.
Did you round off the intersection in your venturi Julian? Are you still on a cast one or have you moved to a machined jobbie?
Still on a cast unit, but it's a four port with a separate chamber around the ports. Still doesn't demeth as fast as I'd like ... I'm pretty sure it's pump thing.
I've started wondering if what I know as an ejector, where a jet fires across a void before entering the throat, might not be a better design ... all the serious commercial devices are made that way.
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I wonder if this mystery member can come up with a devise to create cavitation?
I'll have a word with him, his identity must remain secret though coz I'm keepin' to meself, so there.
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I've started wondering if what I know as an ejector, where a jet fires across a void before entering the throat, might not be a better design ... all the serious commercial devices are made that way.
Wonder no more, during my research period, some 7+ years ago, I play with the ejectors and got one to draw in 10ltr in 28secs using an 80ltr/min pump, that gave a 1:4 ratio.
Yes they are very efficient but getting the two diams to line up exactly can be a bit fiddly, you can vary the gap to increase the drawn volume.
Needless to say I did make a a mod or two to the receiving cone to get the 1:4.
The best standard venturi I made used the de Laval Rocket nozzle principle, the complete reverse of the aerofoil shape.
Have a go and see what happens.
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The one with the curvy sides ... tricky to fabricate, but quite easy to cast.
Do I have a stab at yet another venturi ... hmmmm.
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Do I have a stab at yet another venturi ... hmmmm.
Of course you do, every time I have a rummage in the garage I find another prototype venturi, I got loads of'm.
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I was rather saving the fun of making yet another venturi until I remake the processor with square tanks, dust Heather off and put her to work ... still need to work out what she's capable of.
Would quite like a stab at a cavitation device in the mean time though.
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Would quite like a stab at a cavitation device in the mean time though.
Nah, nah, nah, get Heather working a venturi to its max efficiency first, trial it on your existing plant and move on from there.
PS. I can can supply bespoke square tanks with pyramidal cones both top and bottom for the rector and open topped for anything else.
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I'm still not entirely sure i understand this. How can cavitation be induced under pressure, or by spraying?
Surely it needs something like a vacuum being created.
Wouldn't it be easier to induce cavitation by suction?
It's not just pressure, it's a sudden change of pressure which creates, not a bubble, but a void. The void is unsustainable and collapses with the effects described above.
This explains diagrammatically ...
An easy way to create cavitation is indeed on the suction of a pump. If you throttle a valve on the suction, most pumps will cavitate, but it doesn't do the pump much good ...
Or on a boats propeller ...
Thanks. I can see more of what is happening now. Obviously it is fairly violent.
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PS. I can can supply bespoke square tanks with pyramidal cones both top and bottom for the rector and open topped for anything else.
PS ... so can I!
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Nah, nah, nah, get Heather working a venturi to its max efficiency first, trail it your existing plant and move on from there.
Heather is going to need some mother big pipe work ... fitting her to my current plant would crap her style.
I've fitted a removable section of pipe work on my current plant to try different venturis and I'll probably start out by doing the same on the new one.
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Thanks. I can see more of what is happening now. Obviously it is fairly violent.
[/quote]
this is the opposite of the theory used in the acetone reaction idea from a few months ago. do we want violent agitation or gentle blending of the reactants?
this paper looks interesting, and more importantly possible to make in the shed.
http://repositorium.sdum.uminho.pt/bitstream/1822/3674/1/SSChE2005-176p%5B1%5D.pdf
i was thinking plastic tubing and hose clips to pinch the tube to the right shape. if it works you could do it with 15mm to 8mm end feed reducers for a more permanent version. put it inside a water jacket made from 40mm wastepipe to kepp the temperature correct. if you heated the oil first you should not get much temperature drop as the methoxide or ASM is going in in small amounts.
i know the theory works as i have seen bio made using a oscillatory flow reactor.
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There's summat up wiv your link, Bob.
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http://repositorium.sdum.uminho.pt/bitstream/1822/3674/1/SSChE2005-176p%5B1%5D.pdf
seems to work for me. takes me to a pdf of the system.
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HTTP Status 404 - /bitstream/1822/3674/1/SSChE2005-176p[1].pdf
type Status report
message /bitstream/1822/3674/1/SSChE2005-176p[1].pdf
description The requested resource (/bitstream/1822/3674/1/SSChE2005-176p[1].pdf) is not available.
Apache Tomcat/7.0.25
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http://repositorium.sdum.uminho.pt/bitstream/1822/3674/1/SSChE2005-176p%5B1%5D.pdf
seems to work for me. takes me to a pdf of the system.
Interested in seeing that, but like GM, the link doesn't work for me either.
How big is the pdf?
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I used to suffer cavitation in my 110lpm pump, this was when I was running 22mm pipework and only during demeth when the temp was over 75°,
in this case the cavitation is the meths flashing to vapour due to the low pressure at the pump inlet.
It seems there are a few different forms of cavitation, high or low pressure.
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Log out and click the link. Worked for me. Weird.
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the trick to getting the ASM and the oil to mix properly within a OFR (oscillatory flow reactor) is getting the speed of the plunger right. i am thinking windscreen wiper motor. the Cambridge uni one used a cam on the end of the plunger and adjusted the stroke. the pinched tube idea would make it possible to experiment with the method without spending a lot of money. will try it with the plastic tube and hose clips first.
you don't need a large plunger so something like a small pneumatic cylinder might work. some thing like the rig in the video at the start of the thread but just change the middle bit with the pump should work.
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This?
(http://www.ceb.cam.ac.uk/data/images/groups/polymer/OFM/baffled_tube_3d.jpg)
Certainly easy to knock up! Blurb with this diagram states the baffles need sharp edges (presumably to create turbulence), so I'm not sure squashing tubes would work.
You seem to be describing a metering pump for the ASM injection. The fuel emulsification system I worked on used one to dose the water and catalyst mixture. But it would need to be set in respect of the oil flow through the OFR (unless you under dose and assume several passes. A possible drawback would be glycerin accumulation between the baffles unless it was mounted vertically.
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Three meetering pumps here ... http://www.ebay.co.uk/itm/ELECTRONIC-METERING-PUMP-/190927943875?pt=LH_DefaultDomain_3&hash=item2c743138c3#ht_95wt_1134
(http://i.ebayimg.com/t/ELECTRONIC-METERING-PUMP-/00/s/MTA2NlgxNjAw/z/5OoAAOxyA9dSWDU0/$(KGrHqRHJFcFJLvBh5fJBSWDUz8HDg~~60_1.JPG)
Or what about a speed controlled peristeltic pump?
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yes that is the basic system. the squashed tube idea is supposed to work just as well.,and is even easier to knock up. i was thinking you could mix the oil and catalyst together in a container cold or below 65 degrees, and introduce it to the OFR though the plunger then heat it as it is pumped around the system. think that was how they did it at uni,but it was a long time ago and i wasnt taking notes. of course in the modern age you would just film it with your phone. ;) for the plunger i was thinking a toilet cytem diaphragm may work. have to test it in some bio first of course, although it will only be in contact with the oil and meth rather than finished bio.
thge reason i thought it would be worth rearecting this idea was the rig in the cavitaion video is ideal for experimenting. could try both methods and see if which one works best.
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if the link i posted doesn't work. try putting n reis ofr into google. comes up as 2nd entry on google. or did a minute ago.
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Would something like an ultrasonic cleaner work.
100W transducers and driver circuit for ~£70
http://www.ebay.co.uk/itm/100W-ULTRASOUND-GENERATOR-and-40KHz-Ultrasonic-transducer-Cleaner-/221289920476?pt=LH_DefaultDomain_0&hash=item3385e837dc
Maybe attach directly to the reactor and or pipework, although I'm not sure what longterm effect this would have on Copper, maybe stick in onto steel/stainless steel pipe work?
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Would something like an ultrasonic cleaner work.
100W transducers and driver circuit for ~£70
http://www.ebay.co.uk/itm/100W-ULTRASOUND-GENERATOR-and-40KHz-Ultrasonic-transducer-Cleaner-/221289920476?pt=LH_DefaultDomain_0&hash=item3385e837dc
Maybe attach directly to the reactor and or pipework, although I'm not sure what longterm effect this would have on Copper, maybe stick in onto steel/stainless steel pipe work?
Ultrasonic cleaning baths work by creating cavitation and there are some commercial setups use ultrasonics, bit they are much more powerful. Every so often I snipe a load of ultrasonic cleaning baths, but they all go for far more than I'm willing to pay.
What you link to may well do the same as a cleaning bath ... I think it's about the same power ... might be worth a shot if someone is willing to fork out.
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This?
(http://www.ceb.cam.ac.uk/data/images/groups/polymer/OFM/baffled_tube_3d.jpg)
Certainly easy to knock up! Blurb with this diagram states the baffles need sharp edges (presumably to create turbulence), so I'm not sure squashing tubes would work.
I built a version similar to that but swagged copper tube and had 3 running in parallel, compared to a 2 stage educator it was close to useless.
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I've started wondering if what I know as an ejector, where a jet fires across a void before entering the throat, might not be a better design ... all the serious commercial devices are made that way.
I use an ejector on my plant which I made on the lathe at work. It works brilliantly well and in my experience better than a venturi - but then I've never been able to make a venturi perform as others claim.
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My best performing venturi was an ejector, work that one out.
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My best performing venturi was an ejector, work that one out.
I've been slowly comming to that conclusion ... venturis are pants.
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My best performing venturi was an ejector, work that one out.
I've been slowly comming to that conclusion ... venturis are pants.
I've been slowly coming to the conclusion that your venturis are pants.
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They're mother lovely venturis ... and they certainly don't suck!
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They're mother lovely venturis ... and they certainly don't suck!
It's not your venturis, it's the spaghetti that you call pipework that's to blame.
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It's not your venturis, it's the spaghetti that you call pipework that's to blame.
I was going to mention that but then thought I'd done enough pee taking for this thread.
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It's mother lovely pipework too. I guess there's just a vague, outside chance that you might be right, but I'd never admit to it.
It's alright for you chaps with palatial sheds to have lovely straight runs and swept bends, but don't forget all my kit is squeezed into 6' square with only about 4' at the eves. I'd list all the kit I've fitted in but I'd hate to create bio-envy on the forum.
On the up side, PLUG's working OK now I've got the flow metre and filter round the right way and installed a NR valve so the pressure switch doesn't cycle the pump too frequently. It's wonderful not carrying 20 ltr containers round to the drive to fill the car.
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... but then thought I'd done enough pee taking for this thread.
Ha, if that's the best you can do then the art of pee taking is one you've obviously yet to master.
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... but then thought I'd done enough pee taking for this thread.
Ha, if that's the best you can do then the art of pee taking is one you've obviously yet to master.
I have no trouble with devastating sarcastic wit, I can bring grown men to tears in a single sentence but I don't want to turn you into a gibbering wreck, well you do, on the odd occasion, come in handy.
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... I can bring grown men to tears in a single sentence ...
Yes, I've seen that but I never thought it was due to wit ... I put it down to you talking some other form of it.
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Just ordered a 50W transducer and driver board for £35 from HK
http://www.ebay.co.uk/itm/160754562847
Not producing Bio anymore, so I'm going to be experimenting with ultrasonic coffee brewing.
Just posting if anyone else was interested?
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Just ordered a 50W transducer and driver board for £35 from HK
http://www.ebay.co.uk/itm/160754562847
Not producing Bio anymore, so I'm going to be experimenting with ultrasonic coffee brewing.
Just posting if anyone else was interested?
Interested in the 'why' vs. KISS.
Hot water and a few minutes an all that..
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To make ice coffee , brewing warm creates an accidic taste , you can cold brew but that takes 12 hours in the fridge , wondering if I can just sonicate cold milk and coffee in a French press.
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To make ice coffee
Now I'm interested.......
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Sounds like I'll have to keep you guys updated , didn't think you lot would be interested in brewing anything but bio, if it doesn't work out with the coffee I may try some with fresh veg.
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I love good iced coffee. Bad iced coffee is foul, no inbetween.
No such thing on the market in this country. Best I've ever tasted was Northern Territories Iced Coffee in NT, Australia.
Used to, (maybe still is) a coffee shop in Chiang Rai, Thailand, which was nearly as good, on the right day.
Really miss the taste of it. Never thought of making it.
Hmmm, Chicken and chips, followed by a litre of iced coffee, and chain smoking marlboro rolling tobacco, sat on Anzac hill overlooking Alice Springs, as the sun goes down................
Something that will probably never happen again...... :'(
Dribble, dribble, dribble.
http://www.parmalat.com.au/index.php?option=com_content&view=article&id=144&Itemid=108
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Got my Ultrasonic transducer board today although I'm a little confused as to the assembly of the Transducer itself.
Link to image:
https://drive.google.com/file/d/0Bz9Uq7xWshaIN1N4ZmtoRFJyWlMzQ2JGSjVyVHlMY0RvZW40/edit?usp=sharing (https://drive.google.com/file/d/0Bz9Uq7xWshaIN1N4ZmtoRFJyWlMzQ2JGSjVyVHlMY0RvZW40/edit?usp=sharing)
I'm not sure have the vibrations are transferred is this through the centre of the transducer base, as this is about 3mm proud of the rest of the face?
I was just going to epoxy this to the base of a stainless steel Jug, but the fact the centre of the transducer face is proud may not make this possible.
Anyway just wondered your thoughts?
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I know nothing about them, but it looks to me as though either, that little protruding bit fits up into some kind of dimple on the bottom of a glass jar, or, there is supposed to be some kind of spacer between the vibrating thing and the jar, so you don't get glass on metal contact.
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I know nothing about them, but it looks to me as though either, that little protruding bit fits up into some kind of dimple on the bottom of a glass jar, or, there is supposed to be some kind of spacer between the vibrating thing and the jar, so you don't get glass on metal contact.
It is literally as you say , its a bit of metal screwed in , I assume this bit is fixed to the tank and then the transducer screwed on.
Anyway did some testing in the kitchen with the transducer suspended at the surface of the liquid.
Tried a few combinations.
1) Ground coffee and cold water.
2) Ground coffee and cold milk
3) SVO and water.
4) Water and granulated sugar.
Not much success at all really I think the transducer needs to be at the bottom of the tank , altohugh some interesting results with the coffee/water.
Seemed when I turned the transducer on the coffee granules all culmed together, firstly being dispersed evenly in the liquid after a stir then when on they coffee when it touched the side of the glass or other coffee grounds , then clumped.
I can see this may well speed up soap settling, as I would get all the soap to stick together.
I think the logic is that the water is a great conductor of sound and the coffee isn't so they tend to stick to the "quiet" surfaces.
Video
https://drive.google.com/file/d/0Bz9Uq7xWshaIdnIwdHFBejA0RmM/edit?usp=sharing (https://drive.google.com/file/d/0Bz9Uq7xWshaIdnIwdHFBejA0RmM/edit?usp=sharing)
Sorry its uncompressed video , ~64Mb for the 15 seconds :O