Ball Mill Bearings case study - Cooper Bearings

Application Fact Sheet - French Cement Ball MillBall Mill Bearings

High Temperature Expansion into FranceThe Application ProblemA cement plant in the south of France is dependent oncontinuous ball mill operation for powdered limestoneproduction. Shutdown for inspection or maintenance createslengthy and costly non-productive periods.Lubricant retention problems caused by the slow speed and highoperating temperature also created shutdown periods forlubrication replenishment and localised clearing up operations.Cooper solved the sealing problem. Cooper seals retain thelubricant as the seals remain concentric to the shaft at all times.In addition, the original bearing, a sleeve bearing caused seriousshaft damage.This problem is negated by the Cooper bearing asthe inner race clamps directly to the shaft, ensuring no directbearing contact with the shaft preventing further shaft damage.The Cooper Split SolutionTo rectify the problem, Cooper recommended a BCP 28inchEXILOG (extra long inner race with outer grooved race) and GR(fixed) bearings for the main trunnion shaft. This particularbearing required extra expansion capability due to the generatedheat created by the mill. Typically, the shaft temperature is 80 0 Cresulting in shaft expansion of around 10mm which isaccommodated within the bearing.The relatively slowly rotating 26 RPM ball mill is capable of takingheavy loads at around 30 Tonnes per bearing (147kN).Removal of the existing bearing and the installation of the newCooper bearing took place over three days and during this timethe shaft was modified to bring it up to the standard required bythe operator.The Cooper hallmark split to the the shaft feature permitsinspection and maintenance to be carried out at the shortestpossible time. The Cooper solution has solved an operationalproblem and reduced maintenance and inspection time, whichmakes a positive contribution to profitability.Customer Service CentresUK, Africa, Asia, Australasiaand the Middle EastCooper Roller Bearings Co LtdWisbech RoadKing’s LynnNorfolk PE30 5JXEngland.Telephone +44 (0) 1553 763 447Fax +44 (0) 1553 761 113Europe and South AmericaCooper Geteilte Rollenlager GmbHPostfach 100 423Oberbenrader Str 40747704 KrefeldGermany.Telephone + (49) 2151 713 016Fax +(49) 2151 713 010USA and MexicoThe Cooper Split Roller Bearing Corp.5365 Robin Hood Road, Suite BNorfolk,VA 23513USATelephone 757 460 0925Fax 757 464 3067CanadaCooper-Grainger Canada Inc5875 Coopers AvenueMississaugaOntario L4Z 1R9CanadaTelephone 905 890 2266Fax 905 890 2269Issue April 2004RudUK1000v1