What's my issue with using filters for WMO...
*****
They don't work. The End.
I kid... I kid... kinda.
There are several issues with filters that many overlook. First up is cost. Most people don't give much consideration to the cost of replacing filters. Quality spin-on type filters are expensive and don't typically last long. If you are replacing $10-20 filters every 50-100 gallons you process, it really adds up. Sock filters are a good option when it comes to cost vs performance but at the end of the day, you will eventually spend centrifuge money on replacing filters.
Filter ratings. MANY filters give a micron rating but they fail to mention the rating method used. Most filters that do not say their rating method are "nominal" rated. Nominal rated filters can be letting as much as half of the particulate over it's rated size pass right through the filter. That means a 20 micron nominal filter could only catch half of the 20 micron particulate in the oil that flows through the filter. Finding an "absolute" rated filter with a low enough micron rating to be useful is typically difficult and expensive. Absolute rated filters capture 99.9% of the particulate at the given rating and larger.
Even most bag filters are nominal rated but absolute rated bags can be found and are typically cheaper than their spin-on counterparts. Yes they are a pain to work with.. but that's a trade off I'd be willing to take.
The next big issue is moisture. One of the biggest contaminates found in our oils is moisture. Used oil doesn't typically get stored indoors so rain and such can find its way in. Antifreeze, coolants, etc. can also be found. Yes there are moisture separators and what have you... but they don't remove ALL of the moisture. You can find hydro blocking filters, but they are expensive and one slightly wet batch will plug the filter solid. There went another $20.
My last big issue with relying on filters is time. Settling is a requirement (even for using other cleaning methods)... but gravity flowing 50 gallons of oil through a 1 micron absolute rated filter takes a substantial amount of time and babysitting. Your time is worth FAR more than most consider.
With all of that said... if I could go back and start all of this from scratch, I would have purchased a direct drive centrifuge from the start. It would have been vastly cheaper... would have paid for itself that much faster... and I wouldn't have wasted so much time reworking my systems to make them better.
I used filters for ~1-2 years when I first started. Was constantly replacing filters and making messes. Went to a pressure driven centrifuge... processed some of my filtered oil and found visible metal in the bowl. Said no to filters from then on. After 6-8 years with that unit, I purchased my WVO Designs basic unit. The first batch was a night and day difference. The amount of material I pulled from the bowl on the first run was equal to dozens of batches with the pressure drive unit. I removed literal pounds of material from the bowl. After a few videos, I started working with WVO Designs and they sent me the parts to upgrade my basic unit to the extreme. With that said... I've never looked back.
Filter ratings. MANY filters give a micron rating but they fail to mention the rating method used. Most filters that do not say their rating method are "nominal" rated. Nominal rated filters can be letting as much as half of the particulate over it's rated size pass right through the filter. That means a 20 micron nominal filter could only catch half of the 20 micron particulate in the oil that flows through the filter. Finding an "absolute" rated filter with a low enough micron rating to be useful is typically difficult and expensive. Absolute rated filters capture 99.9% of the particulate at the given rating and larger.
Even most bag filters are nominal rated but absolute rated bags can be found and are typically cheaper than their spin-on counterparts. Yes they are a pain to work with.. but that's a trade off I'd be willing to take.
The next big issue is moisture. One of the biggest contaminates found in our oils is moisture. Used oil doesn't typically get stored indoors so rain and such can find its way in. Antifreeze, coolants, etc. can also be found. Yes there are moisture separators and what have you... but they don't remove ALL of the moisture. You can find hydro blocking filters, but they are expensive and one slightly wet batch will plug the filter solid. There went another $20.
My last big issue with relying on filters is time. Settling is a requirement (even for using other cleaning methods)... but gravity flowing 50 gallons of oil through a 1 micron absolute rated filter takes a substantial amount of time and babysitting. Your time is worth FAR more than most consider.
With all of that said... if I could go back and start all of this from scratch, I would have purchased a direct drive centrifuge from the start. It would have been vastly cheaper... would have paid for itself that much faster... and I wouldn't have wasted so much time reworking my systems to make them better.
I used filters for ~1-2 years when I first started. Was constantly replacing filters and making messes. Went to a pressure driven centrifuge... processed some of my filtered oil and found visible metal in the bowl. Said no to filters from then on. After 6-8 years with that unit, I purchased my WVO Designs basic unit. The first batch was a night and day difference. The amount of material I pulled from the bowl on the first run was equal to dozens of batches with the pressure drive unit. I removed literal pounds of material from the bowl. After a few videos, I started working with WVO Designs and they sent me the parts to upgrade my basic unit to the extreme. With that said... I've never looked back.