What particle sizes are UOA and VOA results based on?
Last edited:
Oil analysis- particle size
- Thread starter vinu_neuro
- Start date
- Status
According to Polaris, "Elemental Analysis by ICP (inductively-coupled plasma) detects up to 24 metals...not greater than 10µm in size."
Most labs (including Blackstone) use ICP, which is highly accurate but only detects particles up to a few microns in size, as OldCowboy pointed out.
Some labs (e.g. MRT Labs, used by Dyson Analysis) use RDE, which is less accurate but detects particles up to about 15 microns.
Some labs (e.g. MRT Labs, used by Dyson Analysis) use RDE, which is less accurate but detects particles up to about 15 microns.
Quote:
According to Polaris, "Elemental Analysis by ICP (inductively-coupled plasma) detects up to 24 metals...not greater than 10µm in size."
It more complicated than that. Much more. I also don't believe the 10µm upper limit. Most ICP spray chambers have a cut-off of 5µm. Droplets larger than this overload the plasma.
This is from a paper on analyzing slurries by ICP-OES and is essentially what you have when analyzing oil containing particles using a solution to standardize as oil analysis does:
Quote:
To achieve close to 100% recovery using solution standardization, a consistent particle size of 3 microns or less is generally necessary. Goodall, et al. wisely included the density of the particle into the determination such that the higher the density the smaller the particle size needed to be.
The density comes into play because in a spray chamber the particle size is aerodynamic diameter, which in simplest terms is the particle size times the square root of the density.
Assuming a 5µm aerodynamic diameter upper limit, the maximum particle size seen for lead would be 1.5µm and 3.0µm for aluminum.
The 10µm quoted by Polaris might be for some efficiency
Ed
According to Polaris, "Elemental Analysis by ICP (inductively-coupled plasma) detects up to 24 metals...not greater than 10µm in size."
It more complicated than that. Much more. I also don't believe the 10µm upper limit. Most ICP spray chambers have a cut-off of 5µm. Droplets larger than this overload the plasma.
This is from a paper on analyzing slurries by ICP-OES and is essentially what you have when analyzing oil containing particles using a solution to standardize as oil analysis does:
Quote:
To achieve close to 100% recovery using solution standardization, a consistent particle size of 3 microns or less is generally necessary. Goodall, et al. wisely included the density of the particle into the determination such that the higher the density the smaller the particle size needed to be.
The density comes into play because in a spray chamber the particle size is aerodynamic diameter, which in simplest terms is the particle size times the square root of the density.
Assuming a 5µm aerodynamic diameter upper limit, the maximum particle size seen for lead would be 1.5µm and 3.0µm for aluminum.
The 10µm quoted by Polaris might be for some efficiency
Ed
OVERKILL
$100 Site Donor 2021
Originally Posted By: tig1
A couple of years ago a poster here claimed his Buick showed good UOAs but his cams were completely worn out. Does anyone else remember that.
Are you recalling BuickGN's FUBAR engine that had a "normal" UOA? But the engine was toast?
A couple of years ago a poster here claimed his Buick showed good UOAs but his cams were completely worn out. Does anyone else remember that.
Are you recalling BuickGN's FUBAR engine that had a "normal" UOA? But the engine was toast?
Originally Posted By: OVERK1LL
Originally Posted By: tig1
A couple of years ago a poster here claimed his Buick showed good UOAs but his cams were completely worn out. Does anyone else remember that.
Are you recalling BuickGN's FUBAR engine that had a "normal" UOA? But the engine was toast?
That's it. Thanks. Way to many here put too much importance in PPM metal counts. It's like not being able to see the forest because of the trees.
Originally Posted By: tig1
A couple of years ago a poster here claimed his Buick showed good UOAs but his cams were completely worn out. Does anyone else remember that.
Are you recalling BuickGN's FUBAR engine that had a "normal" UOA? But the engine was toast?
That's it. Thanks. Way to many here put too much importance in PPM metal counts. It's like not being able to see the forest because of the trees.
Originally Posted By: vinu_neuro
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2065149&page=2
It was post like these why I don't waste money on UOAs. The exception would be if coolant began the disapear and I couldn't find where it was going, etc.
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2065149&page=2
It was post like these why I don't waste money on UOAs. The exception would be if coolant began the disapear and I couldn't find where it was going, etc.
- Status
Similar threads
