RE: [compost_tea] dirty filters

From: Mike Bosko <mjbosko_at_jmtsystems.com>
Date: Wed, 24 Sep 2003 21:18:50 -0700

This has always been my thought as well. Whats a filter do for you, in
terms of AACT, if after the first 10 minutes it, well, does its job? Doing
its job means to block particles. Blocking particles means to block flow -
and thus reducing the flow size of the filter (mesh, micron, whatever).
After a short amount of time, your mesh size (or whatever, I'm not going
there) is made smaller anyway. Its going to end up blocking the good stuff
in a very short time - no?

I too am working to design a filterless spray system - And many thanks to
Bob, for his offlist engineering ideas to help me get closer - great ideas.
I'm excited to see what you have to bring to the table next year. I know,
we can use a standardized test to test it against the other sprayers out
ther..... oh, nevermind. =)

Mike

  -----Original Message-----
  From: Robert Norsen [mailto:bnbrew_at_yahoo.com]
  Sent: Wednesday, September 24, 2003 8:44 PM
  To: compost_tea_at_yahoogroups.com
  Subject: Re: [compost_tea] dirty filters


  Now that you have massaged the details of filters until they are worn thin
consider this: As you filter ACT + crap thru the filter, what won't go thru
hangs up on the filter, right? Like a beaver dam only dam small. So now
the holes that were some size are half or more closed with what the filter
held back. A 100 micron filter is anywhere from 100 to 0 microns. Water
molecules still go thru. But some or many of the microbes that were going to
go thru a clean filter are blocked by a dirty filter. Are you gaining a lot
of useful brewer design based on a precise filter size? A filter that
allows bacteria but stops fungi? Not good. A filter that passes fingi but
stops protozoa? Not good. A filter that passes protozoa but stops
............ Earthworm eggs? What part of ACT is not useful?

  Or is it better strategy to let larger particles stay in the ACT and
design a system that allows the course particles to go to the field or
garden where nature can welcome them ? No filter. No plugs. Tthat is the
system we will offer for the spring of 2004.

      Bob of Bob's Brewers


  Kirk Leonard <kirk_at_oregonatural.com> wrote:
    I think this horse is rode and I'm glad I'm not the only one who was
    confused. I'm still prone to some confusion but understand much better
than
    the first time we discussed this.

    "Mesh is an inexact measure" my new filter sales guy says today. Ya.
Finally
    got that.

    "Microns are an absolute number." Exactly.

    "Mesh and microns are inversely related." Got that finally, too.

    The size of openings in a filter is what you want to know most, hmm?
Mesh
    values, and mesh tables, vary by manufacturer and material. Together
with
    the opening size and wire or fiber diameter, you can calculate a mesh
using
    twpinc.com's calculator if you want to. In any event, you have to know
two
    of these things to figure out the third.

    If you're looking at mesh, you need to know the diameter of the material
to
    figure if it's actually the opening size you think it is. If your
supplier
    gave you a mesh table, presumably you can ignore this problem. If you
have
    a good micrometer or mm ruler and a good eye you could measure it, since
we
    are talking visible range here (unlike most compost tea contents).

    The variance among same mesh values and actual opening sizes is
explained by
    the diameter of the material, hmm? Tables I've seen tell me the variance
in
    diameters can be a good bit (even within tables, it seems, definitely
    between).

    If you know a mesh value and opening size, you can even get what
diameter
    material it's made of, too. Hey, we can get fancy here... Dennis' is
    definitely a chunky filter, I'd guess.

    I'm still curious what you paid $67 for, guy. Sounds like it might be
    stainless or monofilament? Formed? Framed? Sorry, though, don't think
    you're gonna get very many 6.35mm X 1.5875mm critters through a 1.2mm
filter
    (which is probably fine, anyway... all we need to do is lodge them live,
    whatever size, and most in tea are smaller, right?). Maybe they could
    slip-slide through sideways occasionally, depends how thick or slithery
they
    are, I suppose...

    I gotta say how ironic it is to be struggling with openings in microns
and
    meshes in inches. I mean, I can really work easily with a measure of
    .000039 inches... huh? "Mesh" seems to be some kind of industrial
    "standard" that never became one, other than the rule of thumb that says
    lower mesh numbers mean bigger openings, which is definitely useful but
    occasionally confusing, though less so now.:) That might be as good a
    story as 4 foot 8 inch railroad tracks. Anybody know the mesh story?

    Thanks folks. I will never look at baby powder quite the same way
again.

    -- Kirk













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Received on Thu Sep 25 2003 - 01:13:25 EDT

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