Series MNKA,
acc. to ASME
Page 16
9250-050-en
Revision 11
TM 7903
Edition 07/2010
7
Maintenance
7.1 Screw connections of the
housing (casing)
After initial loading by the operating pressure and
operating temperature the tightening torques of all
connection screws must be checked at the following
points:
housing (casing) flange
suction flange
discharge flange
See also
Section 6.1.1, para. 1
.
7.2 Bearing pedestal
The temperature of the bearing pedestal is
not to exceed more than 122 °F (50 °C) and
under no circumstances 176 °F (80 °C).
If higher temperatures do occur, call in qualified staff
without delay. If this is not possible, the pump must be
shut down and taken out of service.
In many cases a vibration measurement is
recommended to detect bearing wear in good time.
7.2.1 Grease for life lubrication
Grease fill bearings of the series 2RS are installed as
standard features. The grease is lithium-saponified.
The admissible temperature range is – 22 °F to 230 °F
(– 30 °C to + 110 °C).
The rolling bearings are designed for an L
10
service
life of > 17,500 hours. The service life of the grease
filling guaranteed by the bearing manufacturers is
given in the following table.
Size
Bearing size > Service life
Group 1
6207-2RS / 15000 hr*
Group 2
6210-2RS / 15000 hr*
*
at bearing temperature < 122 °F (50 °C)
at bearing temperature 158 °F (70 °C) approx. 7500 hr
If the pump is serviced, it is recommended to also
replace the bearings as a precaution.
In potentially explosive works it is
advisable to monitor the condition of
the rolling bearings.
7.2.2 Oil bath lubrication
We recommend a mineral oil with the following
characteristics for an expected bearing temperature of
about 158 °F (70 °C):
Viscosity index : approx. 85
Kinematic viscosity at 104 °F (40 °C)
:
s
2
mm
40
.
appr
A fully synthetic gear oil to ISO VG 220 is to be used
for temperatures below – 68 °F (– 20 °C).
Replacing the bearings:
The ball bearings are
designed for an L
10
service life of >17,500 hours.
We recommend 17.500 working hours respectively
every 3 years a change of bearing should be made.
Oil changes:
1x per year at bearing temperatures of
about 122 °F (50 °C).
Every 6 months at bearing temperatures of about
158 °F (70 °C).
At higher temperatures more frequently in accordance
with the regulations.
When the pump is serviced, it is recommended to
replace the bearings and shaft seals as a precaution
and to pour in fresh oil.
Oil level check:
The oil level is to be regularly
checked on the constant level oiler
638/1
to ensure
safe operation.
It must be ensured that there is always oil in the
constant level oiler; it must under no circumstances be
completely drained.
In potentially explosive works it is
advisable to monitor the condition of
the ball bearings
If there is a suspicion that splash water could have
entered the bearing pedestal, the oil must be replaced
immediately. Even small amounts of water in the oil
reduce the service life of the ball bearings to a fraction
of the normal service life.
7.3 Cleaning
Care must be taken when cleaning the pump to
ensure that it is not exposed to a strong water jet.
The ingress of water into the bearing pedestal will
substantially impair bearing lubrication.
7.4 Stand-by pumps
If a pump is on stand-by, it is to be started up from
time to time. Regularly turn the shaft by hand in the
direction of rotation.
This operation is to be performed more often for
pumps which are exposed to very strong vibrations
from the plant.
When dismantling the pump from the plant, drain it,
thoroughly clean it, seal with flange covers and store
in accordance with the instructions.
