Special undersize bore bearing order win from Revolvo
ERIKS Industrial Services Limited
Continuing its recent success in providing large split roller bearings
for use in ball mills, Revolvo has won an order from a cement plant in
Thailand to supply two large split roller bearings worth a total of
£40,000. One is a standard 850mm bore unit, and the second, a special
849mm bore bearing to cope with an undersize shaft. Revolvo won the
order because of its willingness to manufacture the special size
bearing, and for the overall design of its SRB unit, with a brass
instead of aluminium cage, which was considered more durable in the
The SRB bearings are being used in a ball mill to crush limestone; the
rock actually being fed through the bore of the bearings. The two SRB
are replacement units for aluminium- caged split roller bearings which
have been failing for some time. The problem with replacing these units
has been the issue of an undersized shaft. Both bearing shafts should
be 850mm but, due to wear and tear, one shaft is undersize at 849mm.
This fact meant that the user either had to replace the shaft
completely, a mammoth and costly undertaking, or find a supplier who
would manufacture a special replacement bearing. The company searched
widely for such a supplier, but it was only a chance logging- on to the
Revolvo website that brought a solution.
In addition to its standard sizes, Revolvo manufactures larger,
non-catalogue bearings in sizes up to 1500 mm. These "special" bearings
are used extensively in process and extraction industries worldwide.
Revolvo is able to produce these bearings due its turning capacity up
to 1.8m and its new grinding capability to 1.5metres.
In common with all Revolvo's SRB bearings the Thailand units are being
supplied with machined brass cages. Revolvo's cage design has CNC bored
pockets that are optimised to give very accurate roller guidance, which
prevents skewing, a condition that can lead to edge loading on the
bearing and reduced bearing life.
In addition to providing excellent roller guidance, the Brass cage also
allows operation at higher temperatures up to 140oC without problems,
and operating speeds up to 25% higher, as long as thrust loads are
within design limits. Overall, Brass is one the best cage materials as
it absorbs lubricant and performs well in aggressive environments where
lubrication is marginal.
The ability of SRB split roller bearings to perform reliably in
aggressive cement applications is enhanced by the performance of the
sealing systems available to protect the cartridge bearing units.
Revolvo has developed a special labyrinth seal to exclude the fine,
abrasive & hygroscopic cement dust, which is such a problem for
equipment such as screw conveyors in cement plants. This solution
provides much improved bearing reliability, and longer life with
greatly reduced levels of maintenance.
For further information on this article and related products and
services, please contact your local ERIKS service centre on 0845 006
6000 to find your local service centre.