Page 123 - Rollingbearings

Selecting a suitable oil
Additives Oil change interval Oil change intervals for mineral oils are
shown in table 10, page 122.
Lubricating oils usually contain additives of The oil change interval depends on the
various kinds. The most important ones are operating conditions and the oil type. With
antioxidants, corrosion protection agents, oil-bath lubrication, it is generally suficient
anti-foaming additives, and EP/AW addi- to change the oil once a year, provided the
tives. In the lubrication condition domain operating temperature does not exceed
deined by κ < 1, EP/AW additives are recom- 50 °C (120 °F). Typically, at higher tempera-
mended, but for temperatures above 80 °C tures or with heavy contamination, the oil
(175 °F), a lubricant with EP/AW additives must be changed more often.
should only be used after careful testing. With oil circulation, the interval after
which the oil needs to be changed is deter-
mined by an inspection of the oil quality,
taking into account oxidation and the pres-
ence of water and abrasive particles. Oil life
in circulation systems can be extended by
removing particles and water from the oil.

Table 8
SKF Centralized Lubrication Systems
SKF MonoFlex SKF DuoFlex SKF ProFlex SKF MultiFlex

Lubrication

Type Single-line Dual-line Progressive Multi-line
Suitable lubricants Oil Oil Oil Oil
Grease with NLGI grades Grease with NLGI grades Grease with NLGI grades Grease with NLGI grades B.4
from 000 to 2 from 000 to 3 from 000 to 2 from 000 to 3
Application examples Machine tools, printing, textile Metal working machines, pulp Printing and industrial presses Oil and gas industry,
and off-highway applications and paper industry, mining machines, off-highway appli- heavy industrial
and cement plants, deck cations, wind turbines applications
cranes, power plants

Table 9
Properties of lubricating oil types
Properties Base oil type
Mineral PAO Ester PAG

Pour point [°C] –30 0 –50 –40 –60 –40 approx –30
[°F] –20 .. 30 –60 .. –40 –75 .. –40 approx. –20
Viscosity index low moderate high high
Pressure-viscosity high moderate low to moderate moderate
coeficient

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