INDA 2017

Best of Germany 2014 - Mining Equipment and Mining Technology

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Page 27 of 51

VDMA 26 VDMA MINING SUPPLEMENT • 2017 pumps with a rating of 530 kW or 800 kW and the capability to reliably deliver distinctly larger volume flows than triplex pumps. The advantages for the operator result from the "economy of scale." A large pump is working far more cost-effectively than two or three smaller ones, and clearly needs less space — an important argument in most modernization projects. A lot of detailed design work was, however, required to transfer the basic concept of the triplex design to the quintuplex pump. The crankshaft, for example, is supported by multiple bearings, and the crossheads are oil-spray lubricated rather than splash lubricated so that sufficient lubrication of the center crossheads is ensured as well. The crankshaft is supported in special split bearings. KAMAT has managed to keep spare parts stocking economical by using many common triplex pump parts. The new quintuplex pumps offer the same advantages as the redesigned triplex pumps. They operate at extremely low noise and low-vibration levels and they work at full operating pressure over a speed range in conjunction with speed-controlled drives. Thus, they can ideally be adapted to the respective volume flow requirements, and one single pump is sufficient due to a very large speed control range. "This is primarily achieved through the pump's capability to rotate slowly without affecting the hydrodynamic lubrication of the highly loaded drive elements of the crosshead in particular," Wahl said. "The corresponding design prerequisites are, among others, amply dimensioned crossheads with large surfaces, which absorb a high-surface pressure and preserve the continuity of the lubricant film." Operators see another advantage in the fact that the flow rate of KAMAT pumps is not controlled through circulation valves in on/off technique but through an electronically controlled speed change of the pump. As a result, wear is significantly reduced since the pump, the pipes and the valves are subjected to far less load. Since the valves of circulation valve controls tend to switch multiple times within a few seconds under certain circumstances, extremely high loads are imposed on the entire pump system thus generating pressure shocks. The first 530-kW quintuplex pump was followed by an 800-kW model. The two versions are already produced in series, and the operators benefit from significant cost savings in terms of ener- gy consumption and maintenance and service bills: Three 800-kW pumps — one each as a master, slave and standby unit, a common constellation — are able to generate even very large volume flows at maximum pressures up to 3,500 bar, and thus typical face pres- sures of 350 bar to 380 bar, at highly economical rates. Another control combination, which is also quite common: The master pump is speed-controlled via frequency converters when two high-pressure pumps are in use. The slave pump takes over the basic load once the requirements exceed the delivery capacity of the mas- ter unit. Therefore, only one single-speed-controlled pump is needed to cover a very large control range, which is a substantial cost benefit especially for the mining industry considering the expenses caused by an ATEX-compliant frequency converter, which is approved for use in underground mines. The option of operating all pump models also in the vertical position creates the prerequisite for a space-saving, vertical installation in pump stations close to the face. The next development stage is already under preparation: In the medium term, KAMAT will add a quintuplex pump with a rating of 1,200 kW to its portfolio. New Ultraclass LHD The latest development of GHH Fahrzeuge is the Load Haul Dumper (LHD) LF-21H with a payload of 21 metric tons (mt). The LF-21H is the most powerful and efficient machine and the largest LHD in its class, according to the manufacturer. The LF-21H is equipped with the latest generation of GHH's hydro- static drivetrain, the Efficient Drive System (EDS). The EDS is optimized for the rough conditions of underground mining and achieves both sig- nificant efficiency as well as productivity gains compared to convention- al hydrodynamic drivetrains. In combination with an intelligent monitor- ing system, it guarantees simple operability as well as maintainability. Reduced fuel consumption, very low brake and tire wear as well as high robustness of the system minimize the operating costs. The eco-friendly engine complies with the latest standards, EU Stage IV and EPA Tier 4 final, and thus minimizes the underground ventila- tion requirement and provides 375 kW power. The focus is on ergonomics with a large foot box, two-pedal control with an inch-function and controls adjustable for all oper- ator sizes. The LF-21H is available in different cabin variants for highly efficient mining in low seam applications of min. 2.5 m. A Z-link for hard rock applications is designed for high breakout forces and loading of matching dump trucks. A low profile version of this Z-link and the lowest machine height of its class provide superior visibility even in confined spaces. A great variety of optional assistance systems such as collision avoidance systems and the automatic loading mode grant a high safety standard and simple operation. KAMAT combined an upgraded mechanical drivetrain with a variable speed controller. The new system replaces multiple small pumps with one larger pump.

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