SKF LINCOLN VP Series, Руководство по эксплуатации

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Version 02
EN
3. Overview, functional description
3.3 Information on volume data
In centralized lubrication systems, the nomi-
nal volume is indicated per stroke. This is
calculated from the piston diameter and the
maximum possible stroke of the particular
metering piston, the maximum stroke. The
maximum achievable piston capacity is typi-
cally used as the nominal volume when con-
figuring a progressive metering device,
though the movement of the piston is influ-
enced by various factors such as:
○
Differences in back pressures at the
outlets, for example due to long tubing
lengths or connected roller bearings or
shaft bearings.
○
Stroke frequency (dynamics)
○
Working temperature, viscosity fluctua-
tions due to strong temperature changes
The maximum stroke and thus the piston
capacity/metered quantity can reduce due to
these factors.
The minimum piston stroke, also referred
to as the compulsory stroke, is determined
by the position of the control bores in the
metering device and the control edges on
the metering piston. If only the compulsory
stroke is performed, the metered quantity
at the affected outlet is reduced, which also
increasing the effective number of piston
strokes. The theoretically determined num-
ber of piston strokes can therefore deviate
from the actual measured value. This must
be considered when evaluating pulses on
metering devices with a mounted piston
detector.
The ratio of piston capacity per metering
device outlet determines the distribution
ratio of the quantity of lubricant supplied
to the metering device. This distribution
ratio is usually constant under all operating
conditions.
Figure 2 shows the piston positions of a
metering device section at maximum stroke
and at compulsory stroke (minimum stroke).
Fig. 2 Maximum stro-
ke and compulsory stroke
5
5 5
2
5 2
Maximum stroke for
piston 5 and
piston 2
Compulsory stroke
for position
of piston 5
Maximum stroke
Compulsory stroke