Elastomeric couplings reduce roller table downtime
Quick Flex elastomeric couplings from Lovejoy , manufactured by R + L Hydraulics GmbH , are used by a well-known European steelmaker to drastically reduce downtime .
Text and images by R + L Hydraulics
The harsh environmental conditions in steel mills place extreme requirements on components . The Quick Flex elastomeric couplings transmit torque to drive the roller tables in a hot rolling mill . The thermally stable couplings are low-wear , low-maintenance , and help minimise downtime . In the steelmaking process , molten pig iron produced in the blast furnace is transformed into crude steel in converters . The crude steel is then cast into long strips called slabs in continuous casting lines . The slabs , up to 10m long and weighing as much as 25 tons , are rolled and shaped to form strip steel or steel wire rolls . Glowing from heat , these slabs are transported on roller tables . To avoid high heat damage to the conveying rollers , the slabs must move continuously on the rollers until they cool down or are ready to enter the next processing step . Surrounding equipment component reliability is crucial : “ If a roller table coupling fails , it may be possible to continue working until the next planned stoppage , but this risks damaging the roller ,” says Detlef Peick , Business Development Manager for the couplings division at R + L Hydraulics in Werdohl . “ This leads to longer downtimes for subsequent repairs , and high roller replacement costs . Stopping the roller table avoids damage to the roller , but creates a production bottleneck for the downstream line operations .” Typically in the past , this application has used gear couplings that are good at handling shaft displacements that occur due to the regular temperature fluctuations . Simultaneously , gear couplings safely transmit high turning moments . “ However , gear couplings
Example from a hot rolling mill : a glowing slab is transported on a roller table .
have disadvantages ,” says Detlef Peick . “ They need frequent lubrication and must be opened regularly for inspection at high cost and inconvenience . When the coupling hubs or sleeve bodies need replacement , the gearbox must be removed from the drive shaft and possibly even the electric motor must be removed from its base first . After replacement , the gear mechanism and the electric motor must be realigned to ensure proper functioning . These activities take a lot of time – time which in steelmaking is very expensive .”
Quick Flex QuickFix elastomeric couplings ’ torque transmission capabilities equal those of gear couplings , but the elastomer inserts used in Quick Flex couplings
The Quick Flex elastomeric coupling ’ s design allows easy access to the elastomer insert eliminates metal-on-metal contact that can cause damage and wear to the hubs . The coupling ’ s design allows easy access to the elastomer insert . After loosening a few screws on the easy-toremove covers , inserts can be inspected or replaced in a matter of moments . Different cover options meet a range of application needs . Should a failure occur after all , it may be possible to continue production without jeopardising the roller , as a ruptured elastomer insert interrupts the flow of forces , so the roller table can continue to operate by using the adjacent rolls to move the slabs . The insert can be replaced later in a few minutes , without removing the gearbox or drives . Since Quick Flex couplings do not require lubrication , regular oil checks and relubrication are no longer needed . The elastomer inserts are available in three degrees of hardness and a high temperature-resistant material that protects against overheating if a slab stays on the roller table longer than planned . The Quick Flex coupling series was designed specifically to withstand harsh operating conditions and require only minimal service . In addition to steelmaking , the couplings are ideal for use in mining , oil and gas , food processing , and pulp and paper applications – wherever tough environments place extreme demands on components .
20 Stainless Steel World March 2023 www . stainless-steel-world . net