Cement Americas

WIN 2016

Cement Americas provides comprehensive coverage of the North and South American cement markets from raw material extraction to delivery and tranportation to end user.

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8 CEMENT AMERICAS • Winter 2016 • www.cementamericas.com FEATURE out of the flter separator. Both rotary valves replaced a belt sealed rotary valve which required maintenance work each time a ship was unloaded. The DuroPro- tect 5 rotary valves were installed in 2006 and un- load 617,297 tons annually without any maintenance. The rotary valves were inspected for the frst time in 2013 and only minor wear traces were identifed. ZXQ 600 for lignite conveying A blow-through rotary valve with a rotor diameter of 25 in. feeds 110 tph of dry lignite into a pneumatic conveying system at a pressure of around 14 psi, trans- porting the coal from a vertical roller mill to storage silos. To ensure a long lifetime for the equipment Duro- Protect 4 (chrome in the housing; tungsten carbide on the rotor) wear protection was chosen. Outstanding characteristics of this rotary valve are: No ignition source due to the low rotation velocity of the rotor. • Energy consumption of 5.4 hp, which is an energy saving of more than 90 percent compared to other feeding systems. • Simple foundation size and reduced requirement for supporting steel structure due to the low height of the rotary valve. • Rotary valve tightness is always equal, either under partial or full load, which is especially important in pre-dosed feeding by a mill. ZRC 500 for fly ash handling The drop-through rotary valve ZRC 500 is used to con- vey fy ash in a cement grinding plant at a conveying capacity of 70 tph at around 13 psi. To withstand the wear of the fy ash the rotary valve is executed in Duro- Protect 5. The rotor is closed and has tungsten carbide welding and the housing has a special ceramic lining. The previous screw pump had an energy consump- tion of around 134 hp, which could now be reduced to around 4 hp with the new rotary valve. OPTIMAL DESIGN OF A WEAR RESISTANT DIVERTER VALVE FOR PNEUMATIC CONVEYING SYSTEMS Based on experience collected in the development of wear protection for rotary valves, Coperion has also optimized the design of two diverter valves for use in the minerals industry: the one-channel WRK diverter valve and the two-channel WZK diverter valve. WRK one-channel diverter valve The WRK design uses the effect of product layer pro- tection inside in the housing. As shown in Figure 13, during operation a layer of product builds up in front of the rotating part, protecting and reducing wear of the gray cast housing of the diverter valve. In addition to minimized maintenance parts and downtime, the WRK has an inspection opening whereby the rotating part of the diverter valve can be replaced very quickly in situ e.g. on a silo. Figure 11: ZXQ 600 for lignite conveying. Figure 12: WRK with product layer.

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