Seeking better membrane filters

[Michael S Ford <MFORD@pantex.com>]

Dear Group,

We having been having "roll up" problems with our membrane filters
that we use for air sampling and are looking for a suitable
replacement.

Specifically, we are using a Millipore Teflon (PTFE) membrane filter
with a black polypropylene backing; 47 mm; 5 micron avg pore size.

Due to the packaging of the filter, it has a tendency to roll up on the
counter planchets and requires us to glue or tape them down.  This
is a real pain.  We have tried to work with the manufacturer in
requesting a fix to this problem, but they have been unresponsive.

We would like to use this same type of filter due to its low flow
resistance and superior resolution characteristics (i.e., PTFE
membrane with poly-backing for ruggedness).

Does anyone know of or use a filter of this type this does not have a
"roll-up" problem?

Any suggestions would be greatly appreciated,
v/r
Michael
mford@pantex.com
************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html