By Bearing Manufacturer>Bearing News>Revolvo Won an Order to Supply Two Large Split Roller Bearings
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Revolvo has won an order from a cement plant in Thailand to supply two large split roller bearings worth a total of GBP 40,000 One is a standard 850mm bore unit and the second is a special 849mm bore bearing designed to cope with an undersized 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.
The SRB bearings are being used in a ball mill to crush limestone, with 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 an undersized shaft.
Both bearing shafts should be 850mm but, due to wear and tear, one shaft is 849mm.
This 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.
In addition to its standard sizes, Revolvo manufactures larger, noncatalogue bearings in sizes up to 1500mm.
These "special" bearings are used 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 1.5m.
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 temperatures of up to 140C without problems and operating speeds up to 25% higher, as long as thrust loads are within design limits.
Brass cages absorb lubricants and perform 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 and hygroscopic cement dust, which creates problems for equipment such as screw conveyors in cement plants.