I guess I am at that!
"Micron" defined
- Thread starter Pete Meisinger
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I guess I am at that!
STB
Guru
Looking back, I am remiss that, in my treatise last night I didn't note that if a primary loads up enough, depending upon the configuration, the pressure can push past the seals allowing unfiltered fuel to get to the secondary, potentially fouling it faster. I note this more toward completeness than for any other reason.
As for the 95% * 95%, just note in filter math that isn't 99.75%. The filtering isn't independent, because it could be size, shape or composition of the particle that aided it in sneaking past the primary filter, and the same could aid it in sneaking past the secondary filter. For example, I'd bet the filtration rate for particles exactly 10 microns isn't the same as for those 1 cm, and that texture, shape, etc matter.
Having said that....I'd agree that it'll be "some might clean fuel". And, I'll agree that, "That's the idea." And, there sure ain't nothing wrong with that.
As for the 95% * 95%, just note in filter math that isn't 99.75%. The filtering isn't independent, because it could be size, shape or composition of the particle that aided it in sneaking past the primary filter, and the same could aid it in sneaking past the secondary filter. For example, I'd bet the filtration rate for particles exactly 10 microns isn't the same as for those 1 cm, and that texture, shape, etc matter.
Having said that....I'd agree that it'll be "some might clean fuel". And, I'll agree that, "That's the idea." And, there sure ain't nothing wrong with that.
Brisyboy
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An interesting discussion for the purist but if I can bring it back down to earth a bit ( not as far as vomit though
). I inherited a box of Baldwin filters with the boat which I have continued to use however I realise that no matter how hard I try I cannot find the micon size for them - the local rep wasn`t a help either. How do I find this out?
). I inherited a box of Baldwin filters with the boat which I have continued to use however I realise that no matter how hard I try I cannot find the micon size for them - the local rep wasn`t a help either. How do I find this out?STB
Guru
Hi Brisyboy,
Is there a model number on them? I'd try googling that. If you post it, I'll try googling that
-Greg
Is there a model number on them? I'd try googling that. If you post it, I'll try googling that
-Greg
Comodave
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An interesting discussion for the purist but if I can bring it back down to earth a bit ( not as far as vomit though
My secondary filters do not list a micron size either. I haven’t found a specification anywhere.
dhays
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The Fleetguard filters that I use for my secondary filters do list a micron rating as well as an efficiency.
Here is some reading from a trusted source:
https://stevedmarineconsulting.com/primary-fuel-filters-2-10-30-microns/
Most pumps push much better than they pull. Vacuum readings are very important. Finer filtering works better after a pump than before a pump. Coarser filtering protects the pump and works great, creates less vacuum before the pump.
A quick search didn't provide a link but you can find information from the diesel companies about advances that allowed longer warranties for on-road diesels. Filtration was of key importance.
Filter ratings and filter build quality are two different things. A cheap, low quality, filter can't be trusted. It's micron rating is irrelevant.
Art is the human endeavor in all things. Beauty can be found in high-tech synthetic filter media.
https://stevedmarineconsulting.com/primary-fuel-filters-2-10-30-microns/
Most pumps push much better than they pull. Vacuum readings are very important. Finer filtering works better after a pump than before a pump. Coarser filtering protects the pump and works great, creates less vacuum before the pump.
A quick search didn't provide a link but you can find information from the diesel companies about advances that allowed longer warranties for on-road diesels. Filtration was of key importance.
Filter ratings and filter build quality are two different things. A cheap, low quality, filter can't be trusted. It's micron rating is irrelevant.
Art is the human endeavor in all things. Beauty can be found in high-tech synthetic filter media.
Last edited:
ranger58sb
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I'm a little surprised to see our Cummins FF5285 spin-on secondary fuel filters are rated at 20 micron. I'd have expected 10 micron...
https://catalog.cumminsfiltration.c...rtInformation&partNumber=FF5285&PartType=Fuel, Spin-On&Part=-&criteria=part&_locale=en
-Chris
https://catalog.cumminsfiltration.c...rtInformation&partNumber=FF5285&PartType=Fuel, Spin-On&Part=-&criteria=part&_locale=en
-Chris
FF
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"Finer filtering works better after a pump than before a pump.
This is true if filtering for crud , but the mixing action in the pump makes water removal more difficult.
This is true if filtering for crud , but the mixing action in the pump makes water removal more difficult.
rgano
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Going on 34 years owning Lehmans with low fuel demand and low return and a Yanmar with high demand and fuel return all with Racor 500 filters in the primary role with remotely monitored vacuum, I have and will continue to use 2-micron elements in the Racor and the usual 10-12 micron engine mounted filters. Engine-mounted are much harder or expensive to replace, especially underway, while I could always change a Racor without having to shutdown the engine or even slow down. Yeah, I know all the usual stuff about why this is anti-social behavior; call me rebellious.
RT Firefly
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Greetings,
Mr. rg. Oh, you rebel you...
Mr. rg. Oh, you rebel you...
timb7734
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Filter choices
While it may be logical to use the smallest rated filter in lieu of manufacturers recommendation, that practice is highly suspect in high pressure engines where a 2 micron secondary or primary for that matter can plug in an instant and ruin the pump and injectors before you can shut the engine down.
Read your owners manual, follow the filter recommendations, the rest is ill advised conjecture.
While it may be logical to use the smallest rated filter in lieu of manufacturers recommendation, that practice is highly suspect in high pressure engines where a 2 micron secondary or primary for that matter can plug in an instant and ruin the pump and injectors before you can shut the engine down.
Read your owners manual, follow the filter recommendations, the rest is ill advised conjecture.
Ski in NC
Technical Guru
One thing to consider is that most of the contaminants in a trawler tank are kind of slimy and gooey, and if a bit gets past a filter there is little consequence. It's not like your tanks are full of hardened steel grinding debris or abrasive silicon carbide grit.
On engines with fuel lubed injection pumps, they can create metallic debris, but once that happens, there is already damage. And if pump creates this debris, it goes straight to the injectors with zero filtration.
I don't worry about filtration. Single Racor 900 with either 10 or 30mic, depending on what I have in the shop. On engine is a screw on Cummins/Fleetguard FF 5285, which is rated at 20mic. No problem with this arrangement in over ten years and 2700hrs.
I do notice the 10mic gets a little cloggy before oil change time (250-300hr), but it only takes five minutes to change. The 30mic runs easily through a whole oil change interval, but might load up the secondary quicker.
On engines with fuel lubed injection pumps, they can create metallic debris, but once that happens, there is already damage. And if pump creates this debris, it goes straight to the injectors with zero filtration.
I don't worry about filtration. Single Racor 900 with either 10 or 30mic, depending on what I have in the shop. On engine is a screw on Cummins/Fleetguard FF 5285, which is rated at 20mic. No problem with this arrangement in over ten years and 2700hrs.
I do notice the 10mic gets a little cloggy before oil change time (250-300hr), but it only takes five minutes to change. The 30mic runs easily through a whole oil change interval, but might load up the secondary quicker.
STB
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Brisyboy
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Greg,
Fantastic info and thanks for taking the time to find and post it.
Now, as far as interpretation is concerned, can these filters therefore be rated at 20microns because they filter out virtually 100% of 20 micron particles and I can feel comfortable that they do a pretty good job down to 5 microns.
Remembering what Ski posted re that most of the contamination is soft I can certainly use these filters as primaries but also even secondaries as well?
George
STB
Guru
Hi George,
I'd expect that, when marketing a filter for use as an Nth stage fuel filter, the advertised "micron rating" would correspond to something in the 95% - 98% efficiency range. So, I'd think of your filters as being comparable to others sold as "20 micron (nominal)" filters.
If someone wanted to call them 15 micron filters, I think there is still a solid strong basis for that. In my mind, 10 microns would be a big stretch. And, given the application, labeling them with a smaller number than that would be a off the deep end. I think.
Given that, unless the manufacturer of the motor had another recommendation, I'd expect to find a 30 (or even 40) micron (at 95+%) primary filter upstream. That would likely be enough to protect the primary filter from getting fouled too quickly without changing anything else.
In my thinking, running with a 15 micron or 20 micron filter upstream approximately makes the primary filter into the secondary filter and the secondary filter into a back-up. The filtering would still be to 15 or 20 microns to 95+% efficiency. And, that is fine. your engine would essentially get just as clean fuel as with a 30 micron filter -- but you'd end up having to mess with the primary fuel filter only rarely. The primary would get most of the chunks out.
With a better micron rating than that, e.g. 10 microns, 5 microns, 2 microns (at 95+%), you'd be feeding cleaner fuel to your engine that it otherwise would see. And, you'd be using the 2ndary filter very little -- the primary filter would be much finer.
2 and 5 micron filters just trap so much that probably isn't harmful to old-style engines that I wouldn't bother. It'll just load a filter sooner than need be, forcing more maintenance and corresponding down time than need happen. I think.
So, my choice for a primary would be in the 10-30 micron range. And, so I'd go 10 micron, unless a 30 micron happened to be in the locker or on a super cheap sale, in which case I, personally wouldn't hesitate to use a 30 micron filter.
Just me thinking aloud.
Cheers!
-Greg
I'd expect that, when marketing a filter for use as an Nth stage fuel filter, the advertised "micron rating" would correspond to something in the 95% - 98% efficiency range. So, I'd think of your filters as being comparable to others sold as "20 micron (nominal)" filters.
If someone wanted to call them 15 micron filters, I think there is still a solid strong basis for that. In my mind, 10 microns would be a big stretch. And, given the application, labeling them with a smaller number than that would be a off the deep end. I think.
Given that, unless the manufacturer of the motor had another recommendation, I'd expect to find a 30 (or even 40) micron (at 95+%) primary filter upstream. That would likely be enough to protect the primary filter from getting fouled too quickly without changing anything else.
In my thinking, running with a 15 micron or 20 micron filter upstream approximately makes the primary filter into the secondary filter and the secondary filter into a back-up. The filtering would still be to 15 or 20 microns to 95+% efficiency. And, that is fine. your engine would essentially get just as clean fuel as with a 30 micron filter -- but you'd end up having to mess with the primary fuel filter only rarely. The primary would get most of the chunks out.
With a better micron rating than that, e.g. 10 microns, 5 microns, 2 microns (at 95+%), you'd be feeding cleaner fuel to your engine that it otherwise would see. And, you'd be using the 2ndary filter very little -- the primary filter would be much finer.
2 and 5 micron filters just trap so much that probably isn't harmful to old-style engines that I wouldn't bother. It'll just load a filter sooner than need be, forcing more maintenance and corresponding down time than need happen. I think.
So, my choice for a primary would be in the 10-30 micron range. And, so I'd go 10 micron, unless a 30 micron happened to be in the locker or on a super cheap sale, in which case I, personally wouldn't hesitate to use a 30 micron filter.
Just me thinking aloud.
Cheers!
-Greg
johnma
Guru
almost correct. Filters also have an efficiency rating. Some filters will filter out approx 96% of everything over their rating. Other filters will only filter out 30% of everything over their rating. Thats why some filters are cheap and some are not.
John
