Sintered disc step-down filter stack for material columns in BHO machine

I am having horrible problems with sintered discs clogging in my material columns while running BHO. I currently have a single 5 um sintered disc at the bottom of a jacketed material column that remains at a consistent -60C. Socks are 100um. Discs come out absolutely caked with particulate.

I have made ice water hash and know most of the particulate that falls off the biomass is in the 120um->70um and 70um->40um channels. For this reason I suspect going straight from the 100um sock to the 5um disc is the cause of the rapid clogging.

When I worked in biotech we’d filter thousands of liters of media down to .2um but it would have been insane to go straight to a .2um. We’d step down gradually, starting with a 5um pre-filter and gradually moving to the .2.

My idea is to stack three sintered discs at the bottom of the material column - first around 70um, then 40, then finally a 20 or 5 at the end. In my mind, this should basically triple the total filter surface area and mitigate or solve the clogging.

Has any one done this? Thought about it? I’ve included a picture from a website that gives a rough idea of what I am picturing.

Addendum: The machine has no external CRC so all filtration must take place at the material column.


You shouldn’t need to stack discs. I’m assuming you’re already using a filter paper with the discs. In my experience a 5um is more suited for a CRC coloumn than a material coloumn. Do you have a disc in the 20-50um range you can try instead? As long as the solvent going in is sufficiently cold, and the coloumns are nice and frosty, you shouldn’t be experiencing clogging that would prevent normal operation or experiencing crazy stacks of particulate. There will always be some unwanted stuff getting through the socks, but it shouldn’t leave more particulate than the disc can contain.

Columns are frosty at -60. We never use paper on top of the discs. We just change and sonicate them after every run. Usually a 6" disc can handle about 3kg of dry or 6kg of frozen material before slowing to a crawl. Sometimes more. Sometimes less.

I can try a 40 instead of a 5. Could the 5 also be dewaxing such that it would be gumming it up more than particulate alone? Boss man is convinced we need to go down to a 5 for shatter/batter/sauce even though we don’t CRC.

Try adding some of these. Also a filter paper or some other type of pre-filter on disc helps

Def switch to the 40 and get some “fast” rated filter papers. Do you have available the steel rings that secure filter papers inside the disk? Filter paper will definitely help with clogging issues. Also, many discs have different micron ratings on the top and bottom. Make sure you’re using the lower micron side facing the socks/ceiling, and that the higher micron side is facing the floor. If this isnt being done it will obviously clog up a lot faster. We make shatter/sugar all day with 25-50um discs.

I quit staging my filtration in the material column for just this reason. Shoot your frozen sock full of bio over to its own filter stack with clite545 and a felt tampon on top of the 5um disc. When the particulate builds up on the surface of the clite545 you can just scrape the top inch off the top and get running again without having to deal with a plug at the bottom of the material column.


Funny you mention the water hash microns because a few years back I had the question of I wonder what would happen if you were to have a filter stack that had the exact microns that bubble hash bags use but in filters going down from 220um to 73um and then having a second filter stack for 25um to .1um.

I went on the hunt for tricalmp gasket filters that match bubble hash microns to attempt such a thing but I couldn’t find any premade ones and suppliers were asking too much for fabrication and I don’t have the tools to make my own.

If you accomplish making a filter stack that mimics the bubble hash microns (and possibly make a post sub micron filter stack )please let us know the fabrication service used to make the filters with the microns and prices.


It ended up in the ec

Cartridge filters are the answer.

Increase the surface area and make a filter that isnt 2 dimensional and your clogging issues will go away immediately.



You wouldn’t want a dead end filter for this. It would clog quickly. You would want a lot of movement across the filter face to create turbulence to reduce settling. A cross-flow filter would work better for sorting solids from a water extraction.

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The microns are in series for a bho extraction I worded the thread wrong when I made it .

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I run a stacked sintered disc. 20um into a 1um. No filter paper and get great results making any finish from badder to shatter. The 20um takes a lot longer to get clogged, but I run the 25um socks. The 100um socks were horrible because of the caking up issue. I would recommend switching socks.

I use a paper filter on my sd and change it out after every column…

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Use two separate ( or three) columns for the crc.
One to hold the powders, with multiple paper filters, one with filter plates followed by different micron sizes, and another with just the sintered disks. People think the sintered disks are meant to hold your powders, when it’s not. It’s meant to be a FINAL STAGED FILTRATION SYSTEM TO INSURE NO PARTICLES GET IN FROM THE PREVIOUS COLUMNS.
6*6 2. I USE 4. 3. Last set up is all
C. FILTER PLATES. Your sintered disks
R. 1ST. 50 MICRONS. In order with a .22
C. 2ND. 20 Micron if you can get it
METAL 3RD 10 micron
FILTER with a 5 and 1

I wrote that out thinking it would come out how it looked. Sorry, but gotta go and plan life out.

What up gang? I’m running an ETS MiniMEP and have been experiencing clogging of our sintered disk at the bottom of the material column. I sent out an email to @ETSgang to get some options regarding different filter sizes and maybe some procedural changes to help the gas flow better.

We recently switched from running a backlog of trim to fresh-frozen flower. I run with a Huber Unistat 815 and Huber CS100 at -60C and -20C, respectively. The solvent mixture is 70/30 from Airgas.

My issue is that my techs are having trouble moving the gas from the material column into the collection column. We are at about 100-150psi in the material column and <~10psi in the collection column. Even with inert gas assist up to 150psi, the solvent just won’t move into the collection column with any force. My conclusion is that the disc is clogging quickly during these runs.

I am going to put down some “fast” 20um filter paper in hopes that a dual-stage filter approach can keep the lower micron filter from clogging so quickly.

Has anyone else experienced this? Is it just a matter of keeping the filter clean/changing it out.

On concern is that we are losing time and my company is pushing me to hit 18 runs/day in the ETS MiniMEP. With this slowdown, we are not able to hit that throughput.

Thanks fam!

Gang Gang

I run almost the exact same setup. Active or passive recovery? How many grams per sock? what micron socks? I step down from a 20 sintered to a 1 micron sintered. My socks are 20 microns. 2700 grams of fresh frozen per run. I can run 50+ runs without having to change discs. Just need to make sure your solvent/flower ratio is correct or you are probably dropping so much thca out of your solution it is clogging the plates. I run straight n-butane. Have you checked the filters to see whats clogging them?

Thanks dude!

I am running active with a Corken T91. Packing about 2200g/sock. I have to clarify the sock micron size.

Here is a pic of the clogged disk.

The 100 micron socks that they give you suck and will cause clogging issues