Page 30 - Catalog filters DONALDSON

Auto Parts / Shoptalk

HYDRAULIC FILTRATION

Understanding the
Compatibility of Donaldson
Filter Performance Alternatives This information is provided as an aid to Fluids
Beta Rating System
Filter Media with Hydraulic

understanding fluid filter efficiency terminology
While Donaldson has developed many formula-
based on current ISO, ANSI and NFPA test
tions of media, they can be divided into two broad
standards. It is not proprietary and may be
categories: natural fibers, usually cellulose, and
reproduced or distributed in any manner for
synthetic or man-made fibers.
educational purposes.
What Is Beta Ratio?
Filtered
Media
Synteq
Petroleum-based
Beta ratio (symbolized by ß) is a formula used Fluid to be Recommended
to calculate the filtration efficiency of a particular Cellulose

fluid filter using base data obtained from multi-pass Phosphate Ester Synteq

testing.
Diester Synteq
Synteq
Water Glycol
Shoptalk In a multi-pass test, fluid is continuously injected Water-Oil Emulsion Synteq

with a uniform amount of contaminant (i.e., ISO
medium test dust) then pumped through the filter

Synteq
Biodegradable Fluid

unit being tested. Filter efficiency is determined by
monitoring oil contamination levels upstream and HWCF (high water

downstream of the test filter at specific times. An content fluids) Synteq

automatic particle counter is used to determine Coarse Filtration Wire Mesh
the contamination level. Through this process an
upstream to downstream particle count ratio is
developed, known as the beta ratio. A Note on Seals
Filter Maintenance Kits Beta ratio = particle count in upstream oil for most applications involving petroleum oil and
The formula used to calculate the beta ratio is:
• Filters with seals made of BunaN are appropriate
some high water content fluids. Filters with seals
(x)
particle count in downstream oil

made of Viton or Fluorel (both fluoroelastomers)
®
®
are required when using diesters, phosphate ester
where (x) is a given particle size
®
fluids. Donaldson offers both types. (Viton is a
and Fluorel is a registered trademark of 3M
®
Company.)
Indicates that testing was registered trademark of DuPont Dow Elastomers,
done with APC’s calibrated
with NIST fluid • In Donaldson filters with fluorocarbon elastomer

Liquid Filtration Heads & Filters 10(c) larger with fluids such as phosphate ester and high water

ß
seals, epoxy potting is used to accommodate higher
= 1000
temperature environments and for compatibility
based fluids. The plastisol (heat cured) and ure-
1000 times more
thane (self curing) potting materials used in other
particles upstream
filters perform well with petroleum-based fluids.
than downstream
that are 10 µm and
28 / Auto Parts

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