Fuel Filter Particle Size 1

[SputterNChoke]

I need to determine if a particular filtering media is suitable for pump-mounted, in-tank fuel strainers in automotive applications.

Specifically I need to know what percentage of what particle size is acceptable by OEM and aftermarket fuel strainer manufacturers when choosing a filter media. For example would 90% efficiency @ 10 microns be the minimum acceptable limit?

Also, it would be useful to know the flow-rate and pressure drop.

Can anyone tell me or point me to this information?

 

[WGJ]

I always found that older technology filters for 'in tank' electric fuel pumps tended to be either single layer woven nylon or the 'Saran' weave favoured by GM/AC Rochester. These always seemed to be quoted as 30 micro metres filters, but at what efficiency I don't recall.
Your mention of 90% efficiency at 10 micro metres sounds as if you are considering using a non-woven 'melt blown' filter, is that right?

 

[Chumley]

You didn't mention your specific application.

Some vehicle manufacturers issued TSB's for the removal of the in tank pre pump screen/filter(s) because they easily plugged up causing drivability issues. The main filter which was a 10 micron filter with about 10 sq. ft. of surface area served as the main and only fuel filter although some Bosch fuel pumps also have an internal mesh type screens. Roller cell type pumps are faily durable as long as the particulate loading doesn't get too extreem. Cavitation damage often seems to be more detrimantal long term. See:

http://home.earthlink.net/~mgmcqueary/89j40_3.htm

In automotive loop type fuel supply systems using fuel injection and engines under 3.0 liters displacement, 1.5 liters per minute flow rates @ about 120 p.s.i. initial pressure generally the job done. The pressure drop is limited to about 110% of the minumum system operating pressure which varies depending on many factors. It helps if you supply more specifics with your question.

Chumley

 

[WGJ]

I would caution very strongly about discarding the 'pump pre filter'.
I was aware that some manufacturers in the USA had suffered from gummy deposits accumulating on filters and in some cases there may have been exacerbation of the problem by poorly chosen (cheaper) material in woven filters, which swelled and, in combination with the gummy stuff, reduced the particle size that the filter would pass, also reducing the fuel flow and generating vapour under the right conditions.

I think that the integrated filters you see in some derivations of Bosch EKP3/EKP4 OEM pumps may result from Bosch defending themselves from poor vehicle assembly practice and sloppy service activities, where debris is contained inside the tank and fuel lines before assembly and would otherwise disable the pump quite quickly. I certainly never put Bosch pumps with integrated filters into a production car, prefering to negotiate a decently tidy assembly process and use a well designed filter.
One actual benefit of having a pump inlet filter in the tank is that the sluicing of the fuel around the tank due to vehicle motion will have the effect of clearing woven filters of solid debris - not so much the case with the 'melt blown' filter media.

If you run a road vehicle for any length of time without any pump inlet filtration then accelerated wear and the possibility of jamming are things you will need to live with.

 

[SputterNChoke]

Thank you for the posts.

Let me explain further. We are a distributor among other things of fuel strainers. Since we do not manufacture these ourselves and the line is used to compliment our own products, I do not have the technical specifications. I must rely on our supplier to ensure that these parts are suitable replacements for the OE filters.

Now, I have another supplier that does not have any experience in this field who is developing these products and will sell them to us at a much lower cost. Before approving these new strainers I need to ensure that they are suitable.

The supplier of the filter media (not the same as the filter supplier) claims that the media is suitable for automotive applications. This is in fact what I am trying to determine. There are a wide variety of filter media in use by OE and aftermarket sources with very different filtering efficiencies. What I am trying to determine are the desired performance characteristics of these types of filters.

 

[Chumley]

"I would caution very strongly about discarding the 'pump pre filter'."


Well, yeah, of course, I would too, but if the vehicle manufacturer, in agreement with their vendor(s) says to do that . . . . then puts it in writing and distributes it as a TSB world wide, chances are they didn't base their decision on your opinion or written post at eng-tips!

See my referenced link. Do you know what "gum" is, what it looks like, or how it forms? I might have missed it, but I didn't see any gum in there! But, what do I know, I'm headed to the eye doctor now. Maybe I need new glasses.

Chumley

 

[WGJ]

Sorry Chumley, have I offended your authority by just putting a point of view based on experience from a vehicle designer/manufacturer's perspective?
I didn't say there was a gum deposit referenced to the link, what I said was that I knew of an issue of pump inlet filter obstruction which had been due to a gummy deposit accumulating on inlet filters.
Technical Service Bulletins are also used to get companies out of a pit, not just to assist service operations.
Did the next TSB say 'replace fuel pump'?
No sane vendot/designer of fuel pumps or pump installations would expect to be able to support a warranty of 3 years / 60 000+ miles or similar without a pump inlet filter of some description. Especially in a country with as diverse an environment as the USA.

SputterNChoke: I moved out of fuel delivery work 3 years ago, but I will check with colleagues ref their current picture of media suppliers.

 

[WGJ]

I got the following contact info from my colleagues that are still directly involved with fuel delivery.
Filtertek is one supplier of the 'depth media' type of material and I believe they also still supply woven medias.

Our 'local' contact is:

Filtertek S.A.
Z.A Du Pre de la Dame Jeanne .
60128 Plailly,
France.

Contact Thierry Prat Sales and Marketing Director Europe

Phone 0033 344 54 1990 Fax 0033 344 54 3892

thierry.prat@filtertek.fr <mailto:thierry.prat@filtertek.fr>

However, I see they have an address in Illinois on their website:

http://www.filtertek.com/en/about/worldwide_locations/default.asp