I've just ordered some sock/bag filters online in order to set up my first decent filtration system. I am realizing that a super basic gravity filtration system would be limited by the volume of the bag filter itself. i.e., you could only pour grease into the filter, wait to settle, pour it in, wait to settle, etc.

Wouldn't it be possible to cheaply build an enclosure for the filters that could be sealed? I'm thinking that if the right diameter threaded pipe was found, you could screw a bottleneck piece on either end, sealing the rim of the filter. A pipe/hose could then be attached at either end and pressure could be applied to the system either by putting a 55 gallon drum high up and letting gravity do its work, or using a pump.

Has anyone had any successes or failures with anything like this? Any reason this doesn't seem like it would work?

This message has been edited. Last edited by: TruAvatar,

I have been looking at ways of doing this. I think the best way would be to make a HIH-style T fitting, and make a pipe within a pipe. Then you just have to clamp the mouth of the filter over the inner pipe, and let flow do the rest.

What is an HIH-style T fitting? I'm not sure I understand what you're saying.

The has been discussed here in the some other stheards (seach something like

" DIY bag filter vessel" or "DIY bag filter housing ". Maybe you can come up with creative solutuion . I wound up buying a used one at an industrial surplus yard. Mine maybe available soon since I am planning to use a CF .

I posted my set up at the end of this thread.

Success!

I think...

I bought a 1 micron sock filter online with a 4 inch opening. I then went to the Home Depot and bought a length of 4" PVC pipe as well as reducers and bushings to bring it down to 3/4" on either end. The sock filter fits nicely inside:



Next, I attached an old diesel fuel pump that I had from when I first installed my WVO system and powered it with a battery charger:



The whole rig:


By using a fuel pump to push the grease through the enclosed filter, I was able to filter 10 gallons in about 5 minutes. Also, since this is grease I collected from my own job, straight from the fryer into cubees, I got no bubbles in the hot pan test.

I have some concerns still, though. I didn't cement the top of the enclosure, because if I did, I would never be able to change the filter out. As such, I'm getting some leakage coming from that joint.

Also, I don't really know how to find out if all the oil is being successfully pushed through the filter, as opposed to squeezing around the rim of the filter and straight through the PVC piping. Mabe installing a gasket of some sort? I will probably gravity filter some of the "clean" grease through a fresh 1 micron filter to see if any residue is left.

Nice little rig. As for the leaking problem I would glue up the end where the WVO comes out. Then get 2 toilet flanges and slide it down the tube and glue 1 to the 4 inch tube then glue another one on the cap that goes over the tube then you can screw or clamp them together.

I have cemented all of those joints together other than the one that leaks. I've held off on that because if I cement it together, I'll never be able to open the enclosure to change out the filter bag. Maybe some kind of clamp like you're saying though... even a couple straps that I can crank down to hold that cap on firmly.

quote:

I have some concerns still, though. I didn't cement the top of the enclosure, because if I did, I would never be able to change the filter out. As such, I'm getting some leakage coming from that joint.

I have a similar unit that I use for polishing fuel. I use three machine screws that go in to the circumference of the "top enclosure" and penetrate the pvc pipe just enough to prevent blowoff. I also grooved the od of the pvc tube for an o-ring to prevent leaks. Hate for a blowoff and a huge mess. I also put a o-ring on top and bottom of the plastic ring to ensure no bypass around filter.

quote:

Originally posted by duramadmax:
I have a similar unit that I use for polishing fuel. I use three machine screws that go in to the circumference of the "top enclosure" and penetrate the pvc pipe just enough to prevent blowoff. I also grooved the od of the pvc tube for an o-ring to prevent leaks. Hate for a blowoff and a huge mess. I also put a o-ring on top and bottom of the plastic ring to ensure no bypass around filter.

Those are both excellent ideas. Using a few fine screws to attach the uncemented reducer and putting rubber o-rings or gaskets above and below the plastic rim of the filter would solve much, I think.

I believe you would get much better flow if you used six inch pipe, if you have four inch bags and four inch pipe you are only filtering with the very bottom of the bag, the sides will be pressed against the pipe, also you should be using an absolute filter bag, a nominal bag will pass a lot of stuff larger than one micron.

The gravity system of filtering through bags seems rather slow and inefficient to me so I thought I’d try to speed up the process in a way that was cheap and still effective.
As my dryer uses a pump to squirt the oil into a drum and aerate it to evaporate the water, I wanted to filter the oil “ On the fly” so as it received multiple filtering passes in the process and a very fine filter bag ( 0.5UM) could be used without the worry of the filtering taking and overly long time. By simply pumping in the golden settled oil from my 1000L upflow tanks, I can process the oil in my drying tank which has now become a full on, one shot WVO processor. This Fulfills my goal of a dirty oil in, clean oil out setup with the oil being fully contained in the one process and not having to be handled in between which eliminates work, mess and potential annoying accidents.

Conveniently I found a 150mm PVC Pipe end cap was the perfect size to fit inside a standard filter bag and could be held in place with a large hose clamp ( not shown in pics) to seal the bag so all oil had to pass through it.
There are tank fitting kits available from hardware places but my cheaper solution was to use a short piece of all thread plastic riser ( Brass is available as well) And a couple of backing nuts either side. I drilled a hole in the end cap with a 25mm speed bore which was the perfect size for the standard 20MM riser to fit through. I sealed the nuts and the riser with generous amounts of PVC cement to lock it all into place.

First experiments showed the bag was a little hard to keep in place with the dodgy hose clamp I was using but roughing the smooth outer surface of the cap on a wire wheel to afford the bag some grip fixed that problem. The clamp size needed is around 175M and I have to go pick a couple up so haven’t shown the other crappy one here.

The other problem I found with this arrangement in my drying tank is the weight of the full bag twisted all the fittings to one side. To balance things up I am going to make another bag holder and put that on the other side for balance. I extended the main pipe that goes across the top of the tank so it sits on the top lip on the other side so the weight is supported and not just hanging.

This arrangement could also be used with the bag just hanging over a drum as shown or attached to a 25 or 60L drum to give more filtering capacity and speed up a gravity feed arrangement if a person did not want to use a pump.
I checked with the bag manufacturers as to the pressure these bags were rated to and they told me that the bags were rated to 10PSI for open filtration on critical applications and to 20 PSI for less critical applications where after a support bag or housing was recommended. This means with a standard centrifugal pump or with gravity feed, Using the bags on the mount I have made will still allow them to filter to their rated capacity.



I was initially thinking of enclosing the whole thing bag but found that there were no readily available pipe sizes and adapters that would support the bag without it being pressed against the sides of the pipe and effectively blocking the sides of the bag off. This same setup could be made totally enclosed however by passing the threaded end of the cap through the lid of something like a Plastic 60L drum and then sealing the entire thing like that. If the drum enclosure drum wasn’t drained, a small air hole would also have to be provided to allow the release of air as the drum filled. The threaded section could also be threaded through a piece of board to sit the whole arrangement over the top of larger drums or tanks.

The benefit I see with pressure feeding the bags is the ability to go to the smallest micron rating available and still filter in a timely manner. I think this will be a step in the right direction to give me cleaner oil faster until I get my Centrifuge setup going which I think is the ultimate WVO processing setup and can replace this one shot system with that.Hopefully in the mean time, some others may be able to adapt some of these ideas to make their systems easier, cleaner and more productive!





150mm PVC pipe end cap with threaded riser and backnuts for support.



Edge of cap was roughed up on wire wheel to give filter bag better purchase when secured by hose clamp.



Bag simply slips over outside of end ca] and is held in place with Hose clamp ( Not Shown)



This is how the bag will be placed in my drying tank. To balance the weight, another similiar fitting will be placed on the other side. The valve will control the rate off flow through the bags which will be bled off from the circulation pump that feeds the drying nozzles.



This is a mockup showing how the adapters could also be used with the bags in larger capacity gravity systems.
CAUTION! Make sure the feed drum is secured or weighted down so the weight of a full bag doesn't make the empty drum fall over and make sure the receptacle you are filtering into is at least the capacity of the amount of oil you are delivering from the feed drum.





A 25L plastic drum can be used as well the fitting on the bottom of those is 3/4" standard pipe fittings.



I made this up out of standard 100mm pipe and fittings to use as a support to use with shopping bags or jeans leg filters clamped around it which could be used with a pressure fitting of gravity feed setup. The irrigation Push on hose Fitting has a backnut to secure it under the cap and is sealed with PVC pip cement.
I am thinking of using this to prefilter my oil of particles before I put it in the Upflow tank.

Pvc is great for stuff like this, my idea would be to use threaded pvc fixtures on the end you put the filter bag ring in that way if you got the right size you could just screw it together and that would hold the bag and still be able to take it apart. Or go to bigger size pipe and use bag in bag.

quote:

Originally posted by Charles B:
Pvc is great for stuff like this, my idea would be to use threaded pvc fixtures on the end you put the filter bag ring in that way if you got the right size you could just screw it together and that would hold the bag and still be able to take it apart. Or go to bigger size pipe and use bag in bag.

I was initially going to do this and had seen something on the net of it however I found that the largest pipe size available here ( 150MM) did not take a standard size filter bag properly and that if forced in the rings could buckle and create a gap which would allow unfiltered oil to bypass the bag.

The push on endcaps are $8 here, the screw on caps are around $28 and the screw on lids are $14. For that money, I'll go with the endcap fittings!