In its drive to reduce costs through the electrification of its track-mounted processing units, Keestrack is concentrating on hybrid crushing technology.
Following fully hybrid H4 cone crushers and B4e jaw crushers, the company is now introducing the R5e hybrid impact crusher unit, designed to guarantee full capacity at low consumption costs with the aid of a directly driven 350 tonne per hour crusher and electrical transport and screen components.
Keestrack’s track-mounted impact crusher units include three models, starting with the compact R3, a flexible 30 tonne “construction-site crusher.”
Keestrack’s R6 flagship model has a total weight of 60 tonnes when fully equipped and remains a prominent machine among the 1300-impactors for recycling, large-scale projects and quarrying applications.
Thanks to the licence-exempt dolly transport, it readily competes with the much heavier competition within the 450 tonne per hour performance class. As well, the large-scale “Destroyer” unit has been available for several years as an R6e model in a diesel-electric hybrid version with electric motors driving the conveyor belts and screen components.
Since 2014, the Keestrack R6e has been available with a 250-kW electric motor for the crusher and an electric 110 kW drive for the on-board hydraulic system, and an optional all-electric plug-in operation from the mains. Equipped with a high-performance, on-board diesel engine, the large-scale crushers remain flexible, while up to 45 per cent of the energy costs can be saved, even in semi-stationary operations.
The advantage is reflected in Keestrack’s sales. In 2016, 80 per cent of the R6 machines sold were represented by diesel-electric or all-electric sales. This year, the total number of units sold in 2016 was reached before the end of the first six months — 90 per cent of these being in the form of hybrid or fully hybrid models.
The Keestrack R5 is a mid-range series of models with an about 42 tonne basic weight and a maximum 50 tonnes with an overband magnet and double-deck final screen, including oversize material recycler.
When it was introduced more than three years ago, the mobility and production rate of the diesel-hydraulic crusher proved to be virtually unrivalled for its performance class, according to Keestrack. Now following a series of upgrades, Keestrack presents the R5e, a diesel-electric version of its 350 tonne per hour all-round model.
Similar to the larger R6e impact crusher model, the R5e has a highly efficient 5,100 kg rotor, driven directly via the 345 kW Volvo six-cylinder diesel engine.
The operating hydraulics powers all the lifting cylinders on the chassis and conveyor belts, the track drive, the vibrating discharge chute and double-deck primary screen and the compact double-deck post-screen module with oversize/stockpile conveyor.
A 160-KVa generator now supplies the power to all other conveyor systems — including the 5-cubic metre vibrating feeder – and the new Keestrack Neodym overbelt magnets. On the basis of the anticipated higher mobility compared to the R6e, the Keestrack R5e does not offer plug-in network operation, but can drive the subsequently connected screens or stockpile via the 63 A supply.
With a total additional weight of 500-kg compared to the diesel-hydraulic version, the electrical unit guarantees the full mobility of the Keestrack R5e, which is also available with an optional dolly trailer.
The hybrid unit can be deployed just as quickly at the building site, while all conveyors and additional modules can be configured without lengthy additional assembly work or support.
The system uses load and level sensors to optimize production rate and quality during operations. All system functions can be controlled by radio remote as a standard option.
Practical tests have demonstrated a considerable decrease in fuel consumption of up to 45 per cent compared to diesel-hydraulic models, mainly due to a more even rotational speed of the high-torque Volvo diesel engine. Fundamentally, the extensive reduction of complex hydraulic lines results in lower cooling requirements, lower risks of leakage and lower maintenance demands during everyday operations.