2013 Buyers' Guide 2013 Buyers' Guide - Filtration News

Absorbents | Adsorbents
table salt) can absorb and retain extremely
large amounts of a liquid relative
to their own mass. Additionally,
a SAPs ability to absorb water is a
factor of the ionic concentration of
the aqueous solution. In deionized
and distilled water, a SAP may absorb
500 times its weight (from 30–60
times its own volume), but when put
into a 0.9% saline solution, the absorbency
drops to maybe 50 times its
weight. It is SAPs ability to absorb
aqueous solutions through hydrogen
bonding with water molecules that
make them so attractive for water removal
applications. This SAP affinity
for water results in the water molecules
becoming “trapped” as they
contact the polymer and the SAP particle
expands. The isolated water remains
held in the Gelok laminate
media layer and the decontaminated
hydrocarbon fluid proceeds unaffected
through the system.
Gelok media is best suited as a
cost-effective means of dealing with
small systems that require polishing
to remove or monitor moisture. It
has the advantage of controlling two
of the three forms of water contamination
common to hydrocarbon fluids
while also offering an
opportunity to trap solid forms of
contamination. Hydraulic system
mobile machines or monitoring systems
that only seek to identify and
shut down in the presence of increased
water are two applications
that often employ this media type.
Selection of an absorbent laminate
product ultimately depends on the
targeted requirements of the intended
application. It is important to
bear in mind that super absorbent filters
can remove only a limited volume
of water before causing the filter
to go into pressure-drop induced bypass.
Therefore, media identification
to match the application is essential
to successful filter design. The following
table outlines just a portion of
the considerations that Gelok must
review with all customers when identifying
the correct super absorbent
polymer and substrate combinations
for any given application.
Application Considerations:
• Intended use setting
• Fluid type
• Filter type
• Fluid flow
• Salinity level of the water
• Desired response
Polymer Considerations:
• Speed of SAP response to water
• Total loading of SAP (range
from 10 gsm to 300 gsm)
• Absorbency under load (AUL)
which shows how the SAP
responds under pressure
22 • August 2012 • www.filtnews.com