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WVO Centrifuge progress

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inkblotz
Posts: 8202

WVO Centrifuge progress

Post#1 » Fri Oct 31, 2008 4:55 am

I am coming close to finishing my waste vegetable oil centrifuge. For those of you not familiar here is a little background. Since the WVO will come from the the local restaurant containing various food particles and possibly some water you need a way to remove them to get to the pure vegetable oil. With a centrifuge as you pour the warmed oil into the centrifuge bowl spinning at 3400 RPM the contaminants will be slung to the outer walls and the pure clean oil will remain in the middle as you continue pouring the clean oil will be slung out of the top of the bowl into the exterior housing. this housing has (will have) a drain which will allow you to capture the clean oil. When you have finished you stop the centrifuge remove the bowl (one nut) and clean out the remaining sludge that is left behind.

Currently most people that use WVO use a series of filters that, through gravity, filter the WVO. I did not like the idea of this process as I did not want to continue buying filters and waiting for gravity to do it's thing. I think the centrifuge is a better solution removing more contaminants and there are no filters to replace.

WHAT I USED:
Since a centrifuge spins at high speed, balance is key so I used a laboratory test tube centrifuge (which I bought on EBay for $20) and had a local machine shop carve out the inside to create a bowl. For safety sake I wanted a durable housing the would contain the bowl and have enough room for the slinging of the oil, so I searched for an old school style pressure cooker, in which I cut a large hole in the top to be able to add the oil while still maintaining the slinging oil spray. Next was the motor after much research I found a spa pool pump motor gave me the highest RPM, it was fairly well sealed and its shaft was threaded on the end to lock the bowl in place.

Anyway I just wanted to give you guys a pictorial update of where I am in the process. The researching right parts is the most time consuming. All that I lack now is attaching a frame with 3 legs to the outside of the pressure cooker which will lift the motor and adding a valve to it's bottom to drain the fresh oil.

I will keep you guys posted
Mark
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User avatar
inkblotz
Posts: 8202

Re: WVO Centrifuge progress

Post#2 » Fri Oct 31, 2008 4:57 am

Here is the test tube centrifuge before I had it carved out.

Mark
Attachments
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User avatar
mortinson
Posts: 86

Re: WVO Centrifuge progress

Post#3 » Fri Oct 31, 2008 5:48 am

Impressive! Please continue letting us know how it goes!

User avatar
stevegsmith
Posts: 2666

Re: WVO Centrifuge progress

Post#4 » Fri Oct 31, 2008 8:38 am

Bout friggin time Atlanta!

Looks good. Can't wait to hear how the test run goes. Please have the wife video tape it just in case it goes crazy. Of course it won't....but just in case.

Good luck dude. Safety first. Hope you don't get too greasy :shock:

User avatar
reinhardtius
Posts: 799

Re: WVO Centrifuge progress

Post#5 » Fri Oct 31, 2008 11:54 am

WHOA MAMA

Best of luck with the creation, and please do share the results. I'm with Steve, video would be very cool 8-)

Hunter

User avatar
inkblotz
Posts: 8202

Re: WVO Centrifuge progress

Post#6 » Fri Oct 31, 2008 12:43 pm

I have already run it several times it is perfectly balanced and runs very smooth. On it's maiden voyage when I actually use the WVO oil I will look for signs of trouble like lights dimming and calls from the power company. :D :D

Mark

My design is a take-off on the simplecentrifuge.com design. I was not going to spend $2200 my total came to around $350.

User avatar
inkblotz
Posts: 8202

Re: WVO Centrifuge progress

Post#7 » Sat Nov 01, 2008 4:37 pm

As spoken by Forrest Gump (with the accent please):
"Lieutenant Dan, you've got legs. Magic legs."


Mark :D
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User avatar
stevegsmith
Posts: 2666

Re: WVO Centrifuge progress

Post#8 » Sat Nov 01, 2008 7:29 pm

I've said it before and I'll say it again, nice legs my friend.

Although, I think the household light switch is my favorite part of the design so far.

Keep going dude, keep her going.

scottst
Posts: 2

Re: WVO Centrifuge progress

Post#9 » Mon Nov 03, 2008 8:45 am

I think the rotor you are using is a Sorvall SS-34, which was originally designed to run at up to 21,000 rpm, so your 3600 rpm scenario is probably OK. Rotors do age, and get condemned on age alone, so you should be able to find a lot of them, for aluminum scrap value only. What did it cost to get it bored out?

Larger rotors are available with the same hub, these would include the GSA and GS-3 rotors.

You don't really spend any time on containment. These rotors are designed to be run with a scatter shield. The usual one is steel an inch thick, and it weighs hundreds of pounds. Rotor incidents do occur, especially when you physically change the characteristics of the rotor.

The way you have the centrifuge sitting on a table is also a cause for concern. The legs must somehow be fixed to the table, bolted to brackets or something. A steady state process can become unstable in a hurry, such as if a slug of material is encountered. Sudden imbalance is the nightmare scenario.

I would definitely consider remote shutdown. At this point you can just pull the plug, but I would want to plug the unit in a fair distance (20+ feet or something) away from the unit.

I'd like to see this process automated with a metering pump to feed the raw material. Cheap would be a peristaltic pump, more expensive, but better would be a Viking gear pump. The Viking will pump Crisco, and it could even be heated to aid pumping. Either way, a variable speed drive is used to control flow rate.

User avatar
inkblotz
Posts: 8202

Re: WVO Centrifuge progress

Post#10 » Mon Nov 03, 2008 10:52 am

Thanks for the input.

The way I had planned on introducing the oil was via a gravity feed process where a heated milk container is perched above the unit, It has a 3/8 inch outlet in the bottom. I will attach a valve to regulate the speed of the oil entering the bowl. Attached to the valve will be an aluminum pipe which will extend down into the bottom of the bowl and reside just inward of the top inside edge. The oil will enter at the very bottom and be flung to the widest point of the bowl. My flow rate will be slow and steady.

Mark

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