Author Topic: Sock filters  (Read 4339 times)

honda lee

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Sock filters
« on: April 24, 2013, 02:21:33 PM »
Looking to improve my wvo filtering. I'm wanting input on the best sock type filters and the best places and pricing to get these filters.
At present I am using old gas fryer to heat oil run through filter system for several minutes, then pumping oil out while still hot and filtering once more with paper cartridge  before going into barrel. Thinking of running through sock filter before final use.
Can sock filters be used while oil is still hot?

Thanks for any info Lee


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Re: Sock filters
« Reply #1 on: April 25, 2013, 01:58:19 PM »
I've found that a lot of what plugs filters at point of use is fat solids.
I have had much better luck using filters with cold oil.  It tends to trap the thicker stuff better, although slower.  The only time I heat my oil for filtering is when putting it through the dieselcraft centirfuge.

1982 300SD, 1995 Suburban 6.5, 1994 F250, R170, Metro 6/ sold :( , Witte CD-12 ..... What else can I run on WVO?


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Re: Sock filters
« Reply #2 on: April 25, 2013, 05:29:47 PM »
I'm surprised that you're heating your oil for filtering.  We jokingly refer to WVO as grease but just settling out your oil for a few days might make all the difference in the world. 

I have a 55 gallon drum that I pour the "crap" into through a down tube, 2" PVC, that releases about 6 inches from the bottom.  The bottom is where the white almost chunky stuff sleeps and I don't want to wake that dragon.  About 6 inches from the top on the side of the drum I have a 3/4" tap where I pull about 8 gallons off as needed.  Oh yeah, I pour the raw oil through a 100 micron 5 gallon bucket thing I buy on ebay.  The magic purple cleaner from Walmart is cleans everything up as needed if I don't let it lay around for very long.  Everything is done by gravity.

I sell some of it to a local biodiesel producer once in a while.  I call and he's here the next day.  It's a 70 mile drive so I must be doing something right.  This was also true for the oil I was getting a couple of years ago from a restaurant that I would be uncomfortable feeding my dog from their kitchen.  Yes - I do judge a kitchen by it's WVO.

honda lee,

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honda lee

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Re: Sock filters
« Reply #3 on: April 26, 2013, 01:42:04 AM »
Thanks for the info I never really thought about any down side of filtering hot. I really like the idea of PVC taking oil direct to the bottom, that makes sense.


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Re: Sock filters
« Reply #4 on: May 01, 2013, 10:45:25 AM »

I use the sock filters with Very warm, 50oC oil.

I heat the oil with a waste oil veg burner in a 44 gallon drum I have converted to a processor.  The processor has a pump which re- circulates the oil through the bag filter. I got a 7" PVC pipe end cap and drilled a hole with a speed bore to take a 3/4 Nipple which is bolted both sides of the end cap.  On the grinder wire wheel I roughed up the outer edge of the cap and put a few screws with the round heads a little bit proud. I slip the filter sock over the screws and then with a could of large hose clamps threaded one into the other to make one big clamp, I secure the bag/ sock filter to the end cap.

The pump squirts the oil back into the drum to bubble it up and dry it and at the same time does multiple passes through the bag Filter. I use 5 or 1 UM rated bags.
I generally presettle my oil a long time so fats aren't an issue. If I need to go straight to filtering, I put the oil through one of those Re-useable environmental shopping bags first. These catch the fats and rubbish very well but slow down quick once the fats coat the inside of the bags.  This is a good thing because once that happens they filter very fine as well.  When filtering this way ( not that I do any more, but when I did, ) I would have a bag or 2 hanging over a large bucket and let it drip all day which is usually about what it took to all go through.  Fill the thing at night and take away the cleaned oil and refill with the dirty stuff.

If the oil you have is particularly fatty, you can scrape the fats out with a wooden spoon to speed the bag up a bit. When using a new bag, I try to put the oil through it 2-3 times till the bag coats with fats and slows down. This takes more fats and rubbish out and gives a better end product before you put it through your sock filters.

One thing with the fats is once they are dried, you get a LOT more liquid oil out of them.  If you heat them up and boil them or however you get the oil dry and let it cool, you'll find that what sat in perpetuity as fats, now has a lot of oil that stays liquid on top. You can take this off and put it through your sock filter and it's good to go.
The remaining fat will turn to liquid in the summer when the weather warms up.
For this reason my prefered method is to heat and dry all the oil, filter and then put it in a clean tank and let it settle/ cool off to ambient or below. the fats drop out and the clear oil stays on top.
If you have a bit of heat on your fuel line before the filter ( and you DON'T have to have it hotter than the sun as is parroted on Veg forums) a bit of fat isn't a problem because by the time the filter starts blocking the engine is already warming the oil well and truly enough to melt the fats out anyway. Once dried they only need to get to 35-40oC to turn to liquid.

I have also used the upflow method and it works pretty well.
What I did was get an old water heater and turned it upside down so the domed top was at the bottom. Where the Anode usually screws in the top, I put a drain valve and on the side where the output or relief valve goes was the input. The output is now the former input and I put a long hose on that so I could put it into the drums I was catching it in.

The way my setup was I had a small, cheap marine bilge pump and had that in a bucket I put the dirty oil in. I started it up and then opened the valve ( otherwise the oil will drain out back through the pump) and against the head and pumping oil, the pump slowly pushed the settled, clean oil out from the top.
Basically with this system you want to introduce the dirty oil as slowly as possible to avoid stirring the settled fats and Yecch. You could do it easy enough with gravity, just limit the rate at which the new oil goes in. ( or the clean oil comes out might even be better!)

Before I pumped in the new oil, I opened the bottom drain to take off some of the fats and crap. It won't all come out, with the domed top of the heater it seemed to allow a hole to be  sucked through the crap into the good oil. I just took what I could and then shut it off. I tried to drain some every day even though I wasn't adding new oil every day. If you had a cone bottomed tank, you could drain more but I have seen that cone bottoms still tend to pull immediately above the valve and leave crap to the sides but you do seem to get a lot more rubbish draining out at any given time. 

With the upflow system my rule of thumb was 10% tank capacity in winter and 20% in summer per week.  You can pull double that say if you are going on a trip and need more oil but then I found it was good to give it 2 weeks to catch up again or pull less oil the 2nd week.
If you want say 50L of oil a week, I would suggest a 500L tank. If you want 100L a week, get 2 500L tanks.

Tall tanks like water heaters are MUCH more effective at this than say shorter tanks like IBC's even of much greater capacity. The height from top to bottom is the key. A friend welded 2 44's together end to end and his system was very effective. Frequent drainings to get the crap out were necessary though.
With the upflow system, keep your tank indoors or out of direct sunlight.  What happens is the sun hits one side of the tank and warms the oil and you get convection currents going round in the tank and upsetting the settling.

I like the processor setup personally. I can throw the settled ( or Shopping bag filtered oil) in and 30 min later get clean, dry oil out.  I like doing the multiple passes through the bag filters as they are not 100% rated. some have higher ratings than others but none are 100%.  With a few passes my oil should only have fractions of a percent of oil that doesn't have all the crap taken out. With 1 Um filters that's not even a worry because the bags are absolutely at higher ratings.
IE, A 5 UM bag will take out all 10 UM particles even if there are still some 5-6 bits in there and a 1Um bag will take out 100% of 5 um particles.