LSJr Take on Oil Filter Efficiency Improving with Loading

[ZeeOSix]

He specifically said "dust cake" in his reference to air, oil, & fuel filters. The comment I posted in post #1 is a direct quote, I copied & pasted his reply on the video. Please scroll back to my opening post to review it, thanks!

This is LSJr quote from your post 1:

"The principles of filtration are the same for air, oil and fuel filters. The difference you noted actually comes from the difference in how air filters and oil filters are tested. Air filters are fed test dust at a steady rate over time, so that you can measure efficiency vs loading. Unfortunately, oil filter testing begins with oil that is fully loaded and then continuously adds contaminated oil. As such, the ISO 4548-12 standard does not produce an efficiency vs loading graph. This is where you can see the initial loading of the filter creating a "dust cake" within the media that increases the efficiency of the filter for particles smaller than the absolute particle size."

This pretty much shows that he doesn't understand the difference between an air and oil filter's functionality as they load up with debris, and seems to believe they all work on a "cake/dust layer" that's going to increase the efficiency. If he saw actual raw ISO 4548-12 test data like what Ascent showed us from his testing, he would see that every oil filter that Ascent tested indeed lost efficiency as they loaded up. You have to plot the efficiency lose with debris loading graph from the raw data, like what was done in this post in the Ascent thread --> LINK. And the efficiency drops for pretty much all particles below the absolute partial size of the filter. The absolute particle size is any particle size that the filter is 98.7% and lower efficiency. In the Ascent link above, it clearly shows efficiency loss of particles less than the absolute particle size. And here's where @OVERKILL plotted all the particle sizes for the AC Delco filter that Ascent tested ---> LINK. It lost efficiency in all particles sizes, and most efficiency loss at 15 microns. The smaller the particle size, the the more efficiency loss with loading.

LSJr may be talking about the very first amount of debris loading of an oil filter that might initially close up some pores, as I've seen some really old studies that seem to claim something similar. But with the more modern and accurate ISO 4548-12 test, it's clear that oil filters lose efficiency pretty much from the start as the Ascent data in the links above clearly shows. LSJr might be referencing some 30+ year old tech article, but has never seen raw ISO data plotted out that clearly shows the efficiency decreases with loading.

 

[ZeeOSix]

Galileo was imprisoned for saying the Earth was not the center of the universe......

And some people today still think the Earth is flat ... there's actually a Flat Earth Society LINK ... and they are actually serious.

 

[ZeeOSix]

Well, a "plugged" air filter is less restrictive to air then a new oil filter is to oil. If you tried to run oil through a plugged air filter would it slough off debris?

At 3+ GPM of oil .. no doubt. And if the oil flow volume was hardly anything so the dP was super low (like simply flow from gravity) it would probably increase in efficiency. That's the way any kind of "cake layer" could form effectively on an oil filter with some depth to the media.

 

[kschachn]

For the record, I am very well aware of that as it has been discussed here more than once. While it's possible that LSJR is basing his conclusion on such a basic error, I just think he's smarter than that.

Smarter perhaps, but not sufficiently educated in the topic. People like to overlook that but it is a basic truth. The guy is out of his wheelhouse and doesn't have the technical understanding to know it.

 

[mojoe]

Smarter perhaps, but not sufficiently educated in the topic. People like to overlook that but it is a basic truth. The guy is out of his wheelhouse and doesn't have the technical understanding to know it.

That's your opinion.

 

[Hohn]

At 3+ GPM of oil .. no doubt. And if the oil flow volume was hardly anything so the dP was super low (like simply flow from gravity) it would probably increase in efficiency. That's the way any kind of "cake layer" could form effectively on an oil filter with some depth to the media.

Some pretty interesting and cool things happen if you can get the face velocity on an oil or fuel filter slow enough. You'll see pretty remarkable gains in efficiency at particle sizes much smaller than the pore size.

Obviously a filter with nominally 15 micron pores can't reliably screen out 5-10 micron particles if the mechanism is just purely sieve-screen type removal.

If you've every walked through a field of cockleburrs and had the burrs stick in your pants in such, you might be able to use that to frame a mental model that is the opposite. Imagine wearing a on your legs nothing but burrs and walking though a field of nothing but clothing material. The burrs will come off your legs and onto the stalks of the theoretical blue jean plants.

That's more what happens in depth media. Particles "stick" to fibers and it's more like dragging a yarn ball through a field of the spiky halves of Velcro. Or imagine your are covered with pollen and walking through a super dense crowd of people-- like on mass transit, you'll bump into people and the pollen will be transferred to those you bump into.

With depth filtration like oil or fuel, the force that attracts the particle to the fiber can be quite weak (it's related to VanDerWaal's forces, IIRC). When you slow down the flow slow enough, the particles sort of "float" through through the media and even a very weak attractive force is enough to attract them and make them stick.

And this mechanism is also why depth-style filters generally lose efficiency as they load. This is because the particle load of the filter reduces the effective flow area of the filter, which accelerates the velocity of the fluid through it. And because the fluid is traveling faster, the media not only will fail to catch the lighter, smaller particles anymore, but often it can dislodge the smaller particles that are weakly attached.

This is why just simply enlarging a filter with identical media will often show a notable improvement in filter efficiency over time. Because particle capacity and efficiency are related in that a higher capacity filter will lose efficiency at a slower rate for a given rate of debris accumulation.

This is also why the particles that are "shed" are primarily the smaller, lighter ones first. They have the lowest attraction force retaining them and have no sieve-mechanism backup retention.

 

[kschachn]

That's your opinion.

It's not an opinion that he has a marketing degree. Nothing technical.

 

[garageman402]

Some pretty interesting and cool things happen if you can get the face velocity on an oil or fuel filter slow enough. You'll see pretty remarkable gains in efficiency at particle sizes much smaller than the pore size.

Obviously a filter with nominally 15 micron pores can't reliably screen out 5-10 micron particles if the mechanism is just purely sieve-screen type removal.

If you've every walked through a field of cockleburrs and had the burrs stick in your pants in such, you might be able to use that to frame a mental model that is the opposite. Imagine wearing a on your legs nothing but burrs and walking though a field of nothing but clothing material. The burrs will come off your legs and onto the stalks of the theoretical blue jean plants.

That's more what happens in depth media. Particles "stick" to fibers and it's more like dragging a yarn ball through a field of the spiky halves of Velcro. Or imagine your are covered with pollen and walking through a super dense crowd of people-- like on mass transit, you'll bump into people and the pollen will be transferred to those you bump into.

With depth filtration like oil or fuel, the force that attracts the particle to the fiber can be quite weak (it's related to VanDerWaal's forces, IIRC). When you slow down the flow slow enough, the particles sort of "float" through through the media and even a very weak attractive force is enough to attract them and make them stick.

And this mechanism is also why depth-style filters generally lose efficiency as they load. This is because the particle load of the filter reduces the effective flow are of the filter, which accelerates the velocity of the fluid through it. And because the fluid is traveling faster, the media not only will fail to catch the lighter, smaller particles anymore, but often it can dislodge the smaller particles that are weakly attached.

This is why just simply enlarging a filter with identical media will often show a notable improvement in filter efficiency over time. Because particle capacity and efficiency are related in that a higher capacity filter will lose efficiency at a slower rate for a given rate of debris accumulation.

This is also why the particles that are "shed" are primarily the smaller, lighter ones first. They have the lowest attraction force retaining them and have no sieve-mechanism backup retention.

Great explanation, thank you!! Another reason to use larger filters if space permits.

 

[mojoe]

Yes, I said he’s out of his wheelhouse. Which he is.

Which is your opinion. Which it is.

 

[kschachn]

Which is your opinion. Which it is.

Considering your wheelhouse is confined to calling me and others "haters" when we dare to disagree with portions of his videos, I suppose I'm not surprised.

 

[garageman402]

Please stop the bickering. An admin will lock this thread if it continues. I am getting a lot of useful information from this thread, please don't ruin it. Thank you.

 

[mojoe]

My apologies - I am done.

 

[kschachn]

Please stop the bickering. An admin will lock this thread if it continues. I am getting a lot of useful information from this thread, please don't ruin it. Thank you.

I’d suggest that after seven pages most of the useful technical information has been gleaned from this video. At this point the discussion is pretty degraded to emotion rather than science.

 

[garageman402]

I’d suggest that after seven pages most of the useful technical information has been gleaned from this video. At this point the discussion is pretty degraded to emotion rather than science.

You're probably right, but someone might come along with a fresh prospective that hasn't been covered, or even thought of.

 

[Astro14]

I’d suggest that after seven pages most of the useful technical information has been gleaned from this video. At this point the discussion is pretty degraded to emotion rather than science.

I agree. And I have no desire to keep policing it.

Lock time.