GHH RAND CF75D8 - Filter Fineness; Oil Filter Fineness; Suction Air Filter Fineness; Explanations to the Filter Fineness According to ISO 4572

Installation Manual Series CF (excluding encapsulated screw compressors) 23042013 Rev. A / May 2007 20 of 60
4.8 Filter fineness
4.8.1 Oil filter fineness
Mesh width max. 0.010 mm (10 µm)
For normal operating conditions, filters with a
fineness according to DIN ISO 4572:
β
25
= 75
are recommended.
It is recommended to filter the oil while filling the
oil reservoir, even when filling with fresh clean oil
to prevent any contamination entering the system
In this connection, a fineness according to DIN
ISO 4572:
β
6
= 100
is recommended (see chapter 4.6.3).
The same applies for preservation oils and rins-
ing oils to clean the lubrication system.
4.8.2 Suction air filter fineness
Mesh width max. 0,020 mm for normal indus-
trial air
4.8.3 Explanations to the filter
fineness according to ISO 4572:
• 1. Example: β
25
= 75
98.7 % of the 25 µm particles are filtered
out of the oil.
• 2. Example: β
6
= 100
99 % of 6 µm particles are filtered out of
the oil.
Particle size in µm
Calculation value for the permeabil-
ity rate as follows:
1 / 75 = 1.3 %
The retention degree is:
100 % - 1,.3 % = 98.7 %
1 / 100 = 1 %
The retention degree is:
100 % - 1 % = 99 %