How to / DIY > Everything else
Centrifuges Really Work
snowman18:
This was a small experimental centrifuge that I made to recover precious metals from computer chips, when I started this project knew absolutely nothing of how they worked.
I've used a DC motor with a speed controller the bowl is made from a solid piece of polypropylene which is mounted direct onto the motors shaft.
You can see the gold in the concentrates last image.
My next centrifuge will be used to clean waste cooking oil, I'll be using a spindle from a discarded lawn mower deck but these are cheap enough to purchase new
The tan colored material in the first bowel picture is the precious metals, then when these were extracted copper showed up.
saba:
Interesting to follow,
Once I had ideas about trying to use a clothes dryer/spinner. They are out of fashion and you can pick them up for cheap. Should give some G's and they should keep the mess in the enclosure.
regards bernhard
snowman18:
glort high speed centrifuges are capable of separating isotopes from gaseous mixtures, this is how they enrich uranium.
https://en.wikipedia.org/wiki/Gas_centrifuge
How many G forces was your centrifuge producing, where you running cold oil or did you first heat the oil to improve its viscosity, which would encourage the water to drop out.
The deep fryer operates at temperatures well above the point of evaporating water which is evident when a basket of potatoes chips i first submerged into the hot oil.
The sizzle and bubbling only cease once the top layer of the chip has been cauterized sealing the remaining moisture inside.
Oil is lighter than water, increase the speed of your centrifuge and warm the oil before feeding it into the centrifuge the water has no choice other than to be liberated.
Also have you installed a water separator into your engine fuel system.
Bubbling air through your oil is no guarantee your going to end up drying the oil, air itself has a lot of moisture content.
I have a refrigerated air dryer from a retired dentist similar to the one below. Instead of passing air through the chill plate I'll be passing water used from my still condenser.
snowman18:
Most modern washing machine motors these days are 3 phase running off an inverter incorporated into an onboard module.
The use of a 3 phase motor eliminates the need for a transmission, the motor receives commands from the inverter module for speed and direction of rotation.
If your neighbor had set a broken washing machine to the curb in all probability it has a faulty inverter, the motor should be salvaged for projects like building a centrifuge.
An inexpensive VFD ( variable frequency drive ) is all that is needed to run that motor and they will spin up to 20,000 rpm. Om the video below Raw Power near the beginning of the video says the bowel is operating at 6,000 rpm.
For a bowel the size of the Raw power centrifuge the manufacture is still within the safe limits. But I would not attempt to pull more G force fro that bowel.
Here's a link to calculate g forces generated re diameter and rpm's applied.
http://www.endmemo.com/bio/grpm.php
VFD powering up a repurposed smart drive motor.
https://youtu.be/yaIUp9ZzjYU
Raw Power Centrifuge
https://youtu.be/yaIUp9ZzjYU
snowman18:
--- Quote from: glort on November 10, 2019, 12:49:14 AM ---
--- Quote from: snowman18 on November 09, 2019, 06:02:54 PM ---glort high speed centrifuges are capable of separating isotopes from gaseous mixtures, this is how they enrich uranium.
https://en.wikipedia.org/wiki/Gas_centrifuge
--- End quote ---
Yes, but that's not something you would build yourself or would be able to afford for drying oil.
--- Quote ---How many G forces was your centrifuge producing, where you running cold oil or did you first heat the oil to improve its viscosity, which would encourage the water to drop out.
--- End quote ---
Our centrifuges produced about z G's before self destructing. :( Commercial fuges people have used both the bowl and the jet type do NOT get dissolved water out of oil. There is a big difference between water droplets and dissolved water. Dissolved water particles are very small and the molecular weight is too close to water to seperate by non specialised fuges. Not basing this on my experience with them as much as going on other peoples attempts I have been reading for 15 years plus. Some real smart people have taken this on and never had success UNLESS, they invest considerable energy in heating the oil to drive the water off by evaporation.
--- Quote ---The deep fryer operates at temperatures well above the point of evaporating water which is evident when a basket of potatoes chips i first submerged into the hot oil.
--- End quote ---
Yep, that's what everyone thinks until they they get oil that is wet and learn there are other forces at work. TBH, I forget what they are now, learned and forgot about it a long time ago as it was irrelevant. The frying process even though it typicaly operates at double the boiling point of water does NOT eliminate all the moisture from the oil. Yeah, I know it sounds illogical but it's a well known thing in veg circles not something I made up.
--- Quote ---The sizzle and bubbling only cease once the top layer of the chip has been cauterized sealing the remaining moisture inside.
--- End quote ---
That is not what happens. The moisture continues to escape through the cells of the food while it is being cooked. If all the water was eliminated you would have something as dry as a brick. If the food was sealed, the increasing temperature and steam pressure inside the food would cause it to rupture.
--- Quote ---Oil is lighter than water, increase the speed of your centrifuge and warm the oil before feeding it into the centrifuge the water has no choice other than to be liberated.
--- End quote ---
Again, this -may- be possible on some specialised industrial Fuge but it's not going to happen on a home made bowl fuge before it explodes. Again, many smart people around the world have tried it and no one got dry oil that would pass a simple Hot pan test which is the basic standard of dry oil just by spinning alone.
Not talking about droplets, talking about DISSOLVED water which must be eliminated to prevent a range of problems.
--- Quote --- Also have you installed a water separator into your engine fuel system.
--- End quote ---
Completely and utterly useless against DISSOLVED water. If one is putting oil wet enough to have drop out in their tank, they are very soon going to be one of these people whom complain Veg does not work and caused them problems when the people who prepare the oil right will do it for years without issue. The ONLY separator / filter that is effective against dissolved water is the water block type Filters. Forget who makes them now, Racor Maybe? But they are very expensive ( and bulky) and if you run undried oil through them they will block up fast as is their job.
--- Quote ---Bubbling air through your oil is no guarantee your going to end up drying the oil, air itself has a lot of moisture content.
--- End quote ---
Maybe no guarantee but if you do it right and check it, definitely works and effective. Have the vids demonstrating it. Yes, air does have moisture but unless you are dying on very humid days which a smart person pays attention to and avoids, the humidity in the air is still low enough to dry the dissolved water out of the oil to the required standard. I have also channelled combustion air from a burner though the processor and that really rips the moisture out.
--- Quote ---I have a refrigerated air dryer from a retired dentist similar to the one below. Instead of passing air through the chill plate I'll be passing water used from my still condenser.
--- End quote ---
Refrigeration and vacuum have been used and are very effective but also very energy intensive. I have seen some setups that pump some serious energy into drying and filtering when it's just no necessary. Comes back to the old thing that many seem to believe that unless something is complicated, expensive, energy intensive and has a lot of built in failure points, it can't possibly work. If you have the gear and it's not a lot to run, that would work well but again, that's not the fuge alone drying the oil, it's an extra process.
I would strongly suggest you look up what a hot pan test is and when you have spun up your oil, test it and see how much water you have. Unless you are exceptionally lucky, you WILL have water in any used oil you get. In 17 years I have got oil ONCE that would pass a HPT without drying it.
I would say pretty conservatively I have got over 100K L in the time I have been playing with veg.
When you get it really dry, you can add 3-4 drops of water to a cup of oil, mix it up and still pass the HTP.
--- End quote ---
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