Rock Products

APR 2018

Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market

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www.rockproducts.com ROCK products • April 2018 • 23 lished in the original design. The standard scale in order of ascend- ing clearance is C2, C0, C3, C4, C5. The proper clearance for the ap- plication is critical in that it allows for the challenges of: •  Lubrication. A proper film of lubri- cant must be established between the rolling elements. Reducing internal clearance and impeding lubricant flow can lead to premature failure. • Shaft fit. It is inevitable that there can be a reduction in the Radial Internal Clearance when the bearing is press fit. •  Heat. In the normal operation of bearings there is heat produced that creates thermal expansion of the inner and outer rings. This can reduce the internal clearance, which will reduce the optimal bearing life. Operational Stress and Bearing Selection It is generally the exception to find a bearing that has been improperly designed into an application. However, factors within the larger application may change. If loads become too high, overloading and early fatigue may follow. If they are too low, skidding and improper loading of the rolling elements occur. Early fail- ure will follow in each situation. Similar issues arise with improper internal clearance. The first sign of these issues will be unusual noises and/or increased temperatures. •  Increased temperature. Bearing tem- perature generally rises with start up and stabilizes at a temperature slightly lower than at start up (nor- mally 10 to 40 C higher than room temperature). A desirable bearing temperature is below 100 C. •  Noises. There are typical abnormal bearing sounds that indicate certain issues in the bearing application. While this is a subjective test, it is helpful to know that a screech or howl sound generally indicates too large an internal clearance or poor lubrication on a cylindrical roller bearing while a crunching felt when the shaft is rotated by hand usually indicates contamina- tion of the raceways. See Table 1. Operational stresses in the applications can impact bearing life as well. It is Figure 2 CST Industries | 903 E 104th Street, Suite 900 | Kansas City, MO 64131 | 844-44-TANKS FLAT-PANEL JACK-BUILT STORAGE SOLUTION FULL LINE PRODUCT PORTFOLIO TO OFFER THE RIGHT SOLUTION, EVERY TIME CST is the only tank manufacturer in the world that provides a flat-panel jack-built tank, a chime panel scaffold built tank and factory welded tank designs, all capable of safely and economically being installed on every diverse site imaginable. World-Class Coatings with OptiBond TM Coating Process 125 Years of Experience EMR Rate of .68 350,000 Installations in over 125 Countries W O R L D R E C O G N I Z E D L E A D E R I N D R Y B U L K S T O R A G E TECTANK CP ™ WELDED Optimized Design – Reduced Hardware Required/Reduced Penetration Points Industry Leading Gasket – Leak Proof Design Heavy Duty Jacking System – Proof Load Tested and PE Stamped Preconfigured Models Available – Lead Time Within 10 Weeks of Order CST OptiBond™ Proprietary Coating – Ensures Best Quality Available Faster Construction Time – 20% Faster Than Chime, 30% Faster Than Welded ¨ TECTANK FP ®

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