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Standard tests for determining resistance of grease in the
bearings against water washout run at test temperatures
of 38 °C and 79 °C under defined laboratory conditions
[25]. The tests differ from other field tests in the
operating conditions. The principal scheme of the test
rig conforming to the standards DIN ISO 11009, DIN
51807/2 and ASTM D1264 is shown in the Figure 10.
For running the 60 min. test a grease lubricated open
deep groove ball bearing 6204 is mounted into housing
and rotates at 600 rpm. Amount of grease in the test
bearing is 4 ± 0.05 g. Water jet is sprayed onto the
bearing with the flow rate 5 ± 0.5 cm3/s. The average of
the duplicate tests amount of washed-out grease is a
measure of its water resistance. A general view of the
new design of the machine implementing these tests is
shown in the Figure 11.
The up-to-date tester possesses the following
features and advantages: advanced control and sensor
technique; electronic data acquisition; user friendly
operation and maintenance; two separated water tanks
(Fig. 12) for duplicate or independent testing; two speed
levels 600 rpm and 3780 rpm, while variable speed
control is optionally possible too; test temperature up to
80 °C enables both tests at 38 °C / 79 °C and 40 °C / 80
°C and this way facilitates all the ASTM/DIN
standardised procedures; water tanks are equipped with
control heating unit, so no preheating is necessary; the
machine parts are resistant to brine corrosion; spacious
and easy to clean water tank; separate drive for pump
and bearing makes the belt as in older design (Fig. 10)
unnecessary; magnetic bearing drive for easy
disassembly and removal; volume flow setting by a
precise manual control valve.
For rating of the water washout test results the below
Table 3 is applicable [16].
Table 3. Water washout rating levels
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