Volume 9 Edition 3 2012 - The ASIA Miner

Primary Gyratory Crusherssystem, FLSmidth Minerals can r emotelymonitor and troubleshoot all levels of plantactivity from multiple global locations.Maintenance ImprovementsDuring the past few years, ThyssenKrupp hasgained considerable market share in Asia andAustralia. The company recently received anorder for five gyratory crushers from FreeportIndonesia. Similarly, Detlef Papajewski, headof product division crushing technology ,ThyssenKrupp Fördertechnik, receives similarrequests to accommodate more capacity.The engineers at ThyssenKrupp ar e lookingat ways to incr ease PG throughput, whichwould involve much larger drive sizes. “W ehave installed new gear sets, which allowmuch higher torque,” Papajewski said. “Wehave been doing this with gr eat success forthe last few years now.“We have also improved the overload protectionbetween the crusher motor and thecrusher,” Papajewski said. “If a blockage occurs,such as shovel tooth, a hydraulic safetyclutch separates the crusher fr om the drivetrain, which protects the motor.”ThyssenKrupp has been working on a numberof improvements. From a maintenance aspect,they are looking at new ways to improvethe oil cleaning process for the lubrication system.That extends the time between oilchanges, doubling it from six months to oneyear. “More importantly, the system better protectsthe slide bearing,” Papajewski said. “Particlesin the lubrication could do significantdamage and shorten the life of the bearing.“Another advantage to our design is thatwe have separated the lubrication for the pinionassembly from the lubrication of the slidebearing,” Papajewski said. “If the slide bearinghas experienced troubles with particles inthe return oil, this does not af fect the verysensitive roller bearings found in the pinionassembly. We have a separate bath lubricationsystem for the pinion assembly.”ThyssenKrupp has taken a dif ferent approachto the liners. “We have been working toimprove the concaves to r educe the numberof rows in order to lower downtime,” Papjewskisaid. “In some cases, when the PG is notrunning, the whole mine is down. We are lookingat ways to reduce the downtime associatedwith replacing wear parts. We are also lookingat ways to improve how maintenance is per -formed and to make it as safe as possible.”The GyroMatic control system controls allof the minimum featur es needed to run aThyssenKrupp crusher in a safe manner. “Wehave found that, if the control is managed bya general PLC and ther e is a mistake in theprogram, it can lead to big failur es on thecrusher,” Papajewski said. “We are supplyingall of our PGs with this control software free ofcharge. ThyssenKrupp PGs have a separatePLC that interacts with Siemens, Allen-Bradley, etc. It minimizes programming risksand it also has a bus connection to provide allof the information to an external PLC.“The GyroMatic also provides feedbackto ThyssenKrupp in case the customerwould like us to assist with any questions,”Papajewski said.Building on a Proven DesignIn 2007, Sandvik signed an agr eement withEarth Technica, a division of Kawasaki HeavyIndustries, to license, manufacture, sell andsupport its line of gyratory crushers. In the1960s, Japan’s Kobe Steel became a licenseefor the Allis Chalmers (AC) line of primarygyratory crushers and eventuallytransferred the line to Kawasaki. Through theyears, Kobe Steel made many designchanges before it became Earth Technica.A gyratory is a gyratory, explained VladimirNovak, product line manager gyratory crushers,Sandvik. “With similar designs, they havealmost become a commodity,” said Novak.“Some areas require more attention, such asthe spider bushing area. Everyone uses thishour-glass shaped bushing with linear contact.It’s a wear item that’s not easy to accessand control. If this bearing wears out, it willcreate more problems below in the eccentricbushing area of the crusher.”Sandvik responded with a spherical bearingfor the spider bushing. “This design has a largearea of contact and spreads the forces evenly,”Novak said. “It is very r eliable and requires almostno maintenance. Kawasaki began to usethis particular design in the early 1990s. T odate, not a single bushing has been replaced.”Sandvik’s automation system consists of twocomponents. The company’s ASRi softwarecontrols the position of the main shaft. It tellsthe operators the position, open side setting,wear liner life, etc. Using the ASRi softwar e,miners can create profiles for different crushingapplications. An instrumentation monitoringsystem protects the crusher fr om overloadsand provides opportunities for trending data.Most of the industry operates primary gyratoriesby the open-side setting. That workswell most of the time, Novak explained. “If themine cannot deliver ore to the crusher consistently,it’s either working like it should or thechamber is empty,” Novak said. “That can bedifficult on the manganese liners. After har dworking, the liners attain a hardness of morethan 450 Bhn. Sliding conditions inside thechamber shave off the hardened layer andthe liner wears prematurely.”For those types of conditions, Sandvik’s automatedsystem can operate the crusher bypower consumption. It would close the opensidesetting. The crusher would lose capacity,but the mine operator would not car e at thatpoint. The chamber would be filled. The productwould be crushed to a finer consistency ,which helps with downstr eam processes. Italso eliminates the shaving action.With tighter environmental regulations, oilspillage is a concern. One of the basic maintenanceprocedures is to inspect the r eturnoil screen to see what type of debris is in thelube system. Traditionally, when the mechanicwould open the valve, it spills and it’s sometimesa hazardous situation. The Sandvik designis similar to a drawer in a desk, turn thebypass on, pull the drawer out, and inspectthe screen. “We also have a standby lubricationsystem, filtration unit and pump,” Novaksaid. “Technicians can replace the filters withno extended downtime for the crusher.”The Sandvik PG has mechanically attachedconcave liners for the top shell. “It’s not just theextra security of holding the concave to thetop shell, but also guarantees proper spacingbetween concaves, eliminating the dangeroussituation of closing gaps,” Novak said.Weekly or biweekly someone has to inspectthe gaps. “We have 10-mm shims betweenspider and top shell flanges,” Novak said. “Ifthe tapers are worn, maintenance crews canremove the shims and r eclamp the crusherand operate it for another year or so. No needto panic and repairs can be scheduled whenit’s convenient for the mine.”Sandvik’s first PG, the unit installed at TataSteel, replaced an FLSmidth machine of asimilar size, Novak explained. “Our machineincreased capacity for them by 1,000 mt/h,”Novak said. “We removed the old crusher, installedan apron feeder and the new crusherin 19 days with no incidents. A normal installationtakes 30 to 45 days.”Realizing the need for specialized pr oductsupport, Sandvik recently created a competencecenter to support PGs in Milwaukee. “Wewill establish a global pr oduct support centerand this is just the beginning,” Novak said.68 | ASIA Miner | May/June 2012