On Sun, 30 Nov 2003 17:32:11 GMT, Rich Hampel
wrote:

In article , Keith
wrote:

What's untrue? That a racor element will clog up very fast if you have dirty
fuel?
***** Not in comparison to a cylindrical paper roll. Or do you mean
that the efficiency of a toilt paper roll is soooooo low that it
captures virtually nothing except very large visible particles that is
continues to unload at the same rate that it captures.... and all the
while buirning up amperage to run the pump to overcome the high CLEAN
differential pressure required. If a filter plugs, then it did its job
!!!!!!!!!! Its not the job of a filter to pass particulate at its
designated retention rating. Whats the retention rating of toilet
paper ??????? .... why doesnt it plug up when hit with a slug of
particles???? Have any data on the residual particle level in a tank
after X passes through the 'filter'.

The roll would plug up when hit with a slug of particles. But it takes
much more particles to plug it up then with a pleated roll filter. BTW,
I don't have any data on the residual particle level in a tank after X
passes through the Racor filter either. That doesn't mean it's not
working.

Actually the "surface area" would be much greater in a paper towel,
***** How is the surface of a pleated filter less than the surface of a
cylinder?. Doesnt make sense. A typical pleated 2.5" dia. X 10"
filter has a surface area of 5 to 6 sq. ft. A toilet paper roll of
4.5" dia X 4" long has a surface of 0.4 square ft. Thats 12 to 15
times MORE surface area for the pleated for a normal recirc.
installation.

Now I see where you're confused. You're thinking that particles are
trapped only at the surface of the roll exposed to the incoming fuel.
Well that's just not true. Unlike the pleated filter, the roll can trap
dirt several inches deep. That's why it can trap and hold so much more
particles without plugging... it has a huge volume of material to hold
the dirt and still let fuel pass. There's an exponential decay in the
amout of dirt trapped vs. the depth into the filter you go. Both the
pleated filter and the roll have their entire volume to trap dirt, not
just at the surface. However, the pleated filter *has* to trap dirt
near the surface or it won't get trapped at all since it's so thin.
That's not the case with the roll.

enhance the retention and service life .... plus the addition of
elemental starches for the absorbtion of free water (for 'trimming'
/absorbtion of water emulsion). Without a graded pore density a
cellulosic filter captures virutally ALL the particles on the surface
(cylinder). A paper made into toilet paper or paper towels is made

That hasn't been the case in my situation. When I pull a roll out and
try to peel it apart I can see visible black dirt at least 1/2" into the
roll. And I'm sure there's more further up that I can't see.

from very coarse fiber stock - poor permeability vs. flow AND contains
lots of small chopped fibers that they themselves are free to migrate
out of the paper matrix (particles themselves).

That a toilet paper filter works (at all) depends on LOW differential
pressure (or the cellulose compresses into a 'sludge') but does take

Of course. But you can have a low differential pressure when you're
talking about an element that's several inches to a foot thick.

into account statistical particle reduction of multiple pass filtration
of recirculation mode. Its pretty false economy to have overpriced,
poorly performing/designed housings and then put in a poorly performing
'toilet paper' 'filter' that has NO certifiable retention rating, is
made from paper that is variable in density, is made from paper that is

The fact that it does not have a certifiable retention rating, etc.,
doesn't necessarily mean that all of the tests wouldn't represent good
filtration. It only means that test results would not be repeatable.

specifically MADE TO DIGEST and FALL APART in the presence of
water/liquids. Fibers for toilet paper and paper towel rolls are NOT

Water, yes. Oil, no.

arranged into a graded pore density (the retention of the upsteam
surface is larger than the downstream or exit portion of the depth of
media) such as a typical
TRUE depth filter': which means grade pore density....pores/cpature

Again, just because it doesn't have a graded pore density doesn't mean
it doesn't work. It only means it would work better if it had a graded
pore density.

sites get smaller as one goes deeper into the matrix. For a fixed pre
density (such a roll of toilet paper) what is not captured on the
surface can migrate all-the-way-through the 'filter. Your implication

Of course it can. But so can it with a pleated edge filter. Again,
with the paper rolls, the amount of dirt trapped vs. depth into the
filter exhibits an exponential decline. If it had a graded pore
density, the decline would be more linear. I agree that's a better
situation. But again, that doesn't mean the paper rolls are not a good,
cost effective solution to fuel polishing.

of successive potential sucessive capture sites is only for VERY LARGE
particles as with smaller and smaller size particles the removal
mechanism of inertial impaction capture decrease logrithmically. A
roll of toilet paper will wrinkle-up into a 'little knot' when high
differential pressures are applied while UNLOADING most of the debris
that it originally captured. This 'technology' came out the

Which is why you monitor the filter with vacuum gauges and change it
when the differential reaches more than an couple of pounds.

The pleated resinated paper filter has VASTLY less resistance to flow,
has a defined retention rating, will allow the pump to deliver more
volumetric flow rate and at less amperage draw, requires smaller
housing (on an equal flow basis) @ first /installation cost, has
documented retention, flux. .... because of these advantages will
reduce the resident particles in a tank to nearly undetectable limits
****exponentially faster**** than a filter that inherently DOES NOT
FLOW and has poor retention ability, .... I guess an advantage is that
the amperage draw of such a toilet paper system can help heat the
interior of a boat in winter!

Again, you're showing your inexperience with these fuel polishing
systems. The walbro pump used with these systems doesn't draw more or
heat up if it's flow is constricted. It uses magnetic sensing of the
piston travel to activate the pump. So when the fuel flow rate slows
down, so does the pumping without drawing any more power. In fact, the
way it operates, it actually draws less power as the flow rate slows
down. Yet another way (besides the vacuum gauges) to tell if your
filters are getting clogged is to listen to the pump. You can hear the
"ticking" get slower as the flow rate diminishes.

Please answer the following:
What is the collapse pressure of a toilet paper roll?
What is the particle retention rating on either an absolute basis or
'nominal' rating? How about a beta value? or do you just depends on
'dumb luck'.
What is the loss of efficiency due to the 'knife edge seals? What is
the percent of bypass at 30uM at the knife edge? 20uM, 10uM, 2uM
What is the wet strength rating?
What is the recommended flow rate of a toilet paper roll? How do you
'size' a toilet paper filter to operate at the low motive pressure of a
fuel system? Is it ....."Just BUY one and see if it works" ....
hardly!
Tell me which toilet paper mill makes a 'technical grade' of paper?
Tell again that a rolled paper filter is more efficient than a
'cartridge'. ... include the PRICE of the housing in your
evaluation/reply.
Whats the 'dirt capacity' of a to9ilet paper roll? A 2.5" dia X 10"
pleated typically has about 150 grams capacity..... an equivalent
cartridge true depth filter (in cartridge format) will have about 20-25
grams capacity.

I can't answer any of the below questions for my Racor either. But that
doesn't mean I don't think it works.

Now I have some questions for you. Please answer the following:
Why do you think my 2 micron Racor is not pluged up after installing the
TP filters and running for about 40 hours off of the same fuel that,
before installing the TP filters, completely clogged 2 Racor elements in
a row after 20 minutes each?

Why, when changing the TP filters, do they come out hard and solid with
no noticable disintegration, black on the bottom up to about 1/2" deep
but nice and red at the top?

While there are some black streaks on the side of the element that go up
further then 1/2" (some are maybe 2 or 3 inches long) indicating some
fluid going up the side between the canister and the roll, why have none
of the black streakes ever reached the top of the roll, indicating that
the fuel is still being filtered even as it passes up along the
cartridge side? (I do compress the roll in fairly tightly when
installing it and they are still slightly compressed against the side
when I pull them out.)

All I can suggest to you is "Just BUY one and see if it works" ....

I think you'll find that if you have a dirty fuel problem, this will be
one of the most cost effective solutions to fix it. Of course, if you
don't already have a fuel problem that's bad enough to be clogging up
Racors in only 20 minutes, you won't notice a benefit over just the
Racor.

Steve