Roly Beevor on wed 31 oct 07
Leigh
You weren't so far wrong. The mesh size counts the threads rather than the
holes, and you have to take the width of the thread into account to work out
the hole size, which explains why the US and the old British mesh sizes had
different size holes. Our inches are the same size, a twelfth of 1200/3937
metres.
The micron or millimetre sizes were originally worked out to reflect the
mesh sizes, which explains why the standard micron sizes are rather odd,
such as 71 rather than 70 microns. The numbers give the separation between
the threads, which gives the largest size sphere which will pass through, if
you are lucky enough to want to sieve spheres. The sieve separates
according to the largest dimension of the particles, but in the direction
which presents the smallest largest dimension to the sieve, the geometry is
quite involved, imagine sieveing bananas. You can find that two samples of
material which have passed through the same sieve actually have
significantly different surface area, which can play havoc with industrial
processes.
Of course the size of the holes can vary quite a lot, even if the sieve
meets the relevant Standard.
Roly
-----Original Message-----
From: "Leigh Whitaker"
To:
Date: 31 October 2007 10:34
Subject: Re: Sieve mesh
In a message dated 10/31/2007 12:01:44 A.M. Eastern Standard Time,
vidreiro@GMAIL.COM writes:
Sieve data is abundantly available.
http://www.google.com/search?hl=en&q=sieve+mesh+sizes
Oops! I guess I was entirely wrong!! Please disregard my post about
this!!
Leigh
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