Volume 9 Edition 3 2012 - The ASIA Miner

Slurry PumpsSimulations show reduction in wear “hot spots.”Lower power consumption of WRT compared to standard sustained over a longer period.high yield stress slurries through better headand efficiency maintenance.“We recently installed an AHF pump on athickener underflow application in Australia[See photo, p. 63],” Otten said. “W e wereamazed at how well this type of design comparedwith positive displacement pumps. Wedid test work and we wer e pleasantly surprisedwith some good results.”The AHF uses all of the common parts associatedwith the AH range with a fewchanges to the suction side. The pump relieson a special auger type impeller design. A newcover plate was designed to accommodatethe larger suction arrangement that takes in alot of the air on thicker type slurries. This is anarea where mines have always had applicationproblems, Otten explained. “A centrifugalpump does not like air, that’s one of its biggestdrawbacks, the brand does not matter,” Ottensaid. “This is a very simple change that allowsplant operators to upgrade existing pumps tohandle these types of slurries. Customers arenow interested in installing this design onheavy thickener applications.”Engineered for Harsh DemandsITT Goulds XHD has excelled in two measuresof performance related to moving heavyslurries: high reliability, with design features inevery critical area, which reduce wear and extendequipment life while pumping abrasiveminerals; and easy serviceability , with aunique suction seal ring that can be adjustedwhile the pump is running to maintain optimalimpeller clearance and a split stuffing box forpacking maintenance. The XHD also includesseveral other features that make parts mor eaccessible to perform required maintenancemore quickly, according to ITT Goulds. It isalso relatively easy to install, without changingpiping configurations or pr ocess design. Alow centerline height and the wet-end designallow the XHD pump to be adapted to thefoundations of currently installed slurry pumpsfrom ITT Goulds or other manufacturers.“We feel the XHD delivers with all of thesefeatures and lowers the total cost of owner -ship,” said Buddy Morris, slurry pump pr oductmanager, ITT GouldsUsing the CFD technology, ITT Goulds engineersdesigned the XHD pump for optimal hydraulicoperation—resulting in higher efficiency,longer wear and lower power consumption.“The CFD models allow engineers to smoothtransitions and eliminate eddies, which ultimatelyminimizes wear and energy consumption,”Morris said. Early XHD users havereported drops in electrical consumption of10% to 15% over previously installed pumps.The adjustable suction seal ring maintainsproper clearance and users get longer wearlife—not just for the impeller, but for the entireliquid end of the pump. “The adjustable suctionprevents recirculation and dir ects theproduct back to the pump out vane,” Morrissaid. “It can be adjusted while in operation.”The wet end of the XHD pump is designedas a replaceable cartridge, which allows operatorsto change parts mor e quickly and efficiently.“We have designed this to be a singlecycle wet-end,” Morris said. “The componentswear at the same rate to allow for predictableservice cycles. This feature is ideal for extremeapplications, such as heavy-duty mill cir cuitpumps. With scheduled shutdowns, maintenancecrews do not want to be guessing atwhat parts will be needed. No one wants toreplace a liner and then thr ee weeks later replacethe impeller.” ITT Goulds estimates 30minutes to one hour to remove the liquid endand re–attach a refurbished liquid end.With the quick change wet-end, technicianscam clamp the impeller in place and removethe casing, impellers and liners, all as asingle component and take it to the shop andrepair it. And, you can have a rebuild kit readyto go to replace the unit, Morris explained. Tohelp the process, the pump has a unique, taperedimpeller shaft thr ead to aid r emoval,and for faster r eplacement of the impeller ,with assurance that the shaft and bearingcartridge are properly aligned when the pumpis reassembled. Machined rails, unlike saddle-mountedbearing cartridges, provide positivealignment, accor ding to Morris.“Clamping bolts protect the area completelyfrom excessive wear and corr osion,” Morrissaid. “It’s also easy to re-establish the fit.“Adjustment rods are often found underthe bearing frame, which are difficult to access,”Morris said. “We have placed a setof dual adjustment r ods on top. W e havefound that technicians can adjust with oneof them if they need to.”The new design also includes an impeller releasecollar. “This prevents the impeller from totallybottoming out on the shaft,” Morris said.“Removing the collar allows a few thousandthsof an inch movement to r elease the pressureon the impeller, allowing it to spin off easily.”As far as installation, the XHD has a compactpedestal. The base can be adapted to virtuallyany foundation, Morris explained. “Centers canbe aligned easily for piping,” Morris said. “Replacementsrequire minimal changes and theunits easily adapt to existing plumbing. The lowcenterline allows a very rigid, vibration-free setup.We have also engineered the flanges formore flexibility for existing installations.”Pump wear also is impr oved throughheavy-duty bearings, standard oil lubrication(a grease option is available) and Inpr o Sealbearing isolators. “Impro Seal bearing isolatorsare usually upgrades,” Morris said. “W ehave placed them on the mining pumps becausethey effectively protect the pumps.”The XHD pump’s open seal chamber usesa removable split stuffing box and gland foreasier packing maintenance. Users canchoose their packing arrangement with dedicatedseal water ports, and the stuffing box64 | ASIA Miner | May/June 2012