The specific function of a filter also requires the right filter material.
A number of criteria must be observed for this. Fineness is only one of them.
FABRIC
• mainly for surface filters such as
suction filters
• fineness: 25 μm to 2000 μm
PAPER
• mainly for depth filters for ventilation
• fineness: 5, 10, 25 µm nominal
• cannot be cleaned, disposable element
FIBREGLASS PAPER
• mainly for finest filters with high
compressive load
• fineness: 1, 3, 6, 10, 20 µ absolute as per
ISO 16889
• oil purity as per ISO 4406 to 12/8/2
• high absorption of dirt due to two-layer
technology
• cannot be cleaned, disposable element
AQUASORB
• mainly for bypass filters
• water absorbent
• combined with fiberglass fleece
• cannot be cleaned, disposable element
The choice of the most suitable filter material and the correct processing determines the filter effect decisively.
THE IDEAL FILTER ELEMENT
Three main criteria determine the quality of a filter element: Fineness, dirt absorption and differential pressure. In ideal filter elements, these criteria are in an optimum ratio to each other
Our OEM filter cartridges offer the highest filter effect with maximum dirt absorption and
lowest differential pressure.
CHARACTERISTICS FOR FILTER EFFICIENCY TEST
Filter fineness
• nominal (depending on manufacturer)
• “absolute” as per ISO 16889
• mesh size for woven wire fabric
∆p
Differential pressure
• as per ISO 3968
• referring to 30 cSt
• referring to 25 µm
α
Dirt absorption
• as per ISO 16869
• test dust ACFTD (old
•test dust ISOMTD (new)
All three characteristics depend directly on each other. Therefore, a good filter element will have an ideal ratio of these characteristics. That means: highest filtering effect with maximum dirt absorptionand lowest delta-p.
CROSS-SECTION AND COMPOSITION OF A FILTER CARTRIDGE
