Bauma, one of the world’s leading exhibitions for construction and mining equipment, opened today in Munich. With 17 halls and an expansive outdoor display area, the show has a total exhibition area of more than 600,000 m2—making it the world’s largest trade show. Attendance is expected to exceed 500,000 visitors.
Hydraulics winners of the Bauma Innovation Award
Last night in Munich, top officials from the German construction industry, the German Engineering Federation (VDMA) and Bauma trade fair organizer Messe Munich presented the Bauma Innovation Award for the 11th time.
The award honors R&D teams at companies and universities who have developed cutting-edge, market-ready systems for practical use in construction or mining equipment. The Innovation Award is presented in five categories: machinery, components, construction process/work, research and design. The jury considered 118 applicants from around the world to select three finalists in each category. All nominated innovations are said to offer significant practical benefits and economic potential, contribute towards energy and resource efficiency and improve the workplace.
Among finalists representing hydraulics technology were the STEAM Hybrid Excavator built by RWTH Aachen University in the research sector, pipe-laying equipment from Harald Gollwitzer Spezialtiefbau GmbH in the construction process/work category and a wheeled excavator from Mecalac in the design category.
Hydraulic hybrid excavator
The impetus behind the STEAM excavator, according to Aachen officials, is that fluctuating fuel prices, more stringent emissions regulations and increasing environmental awareness is spurring interest in highly efficient mobile machines, especially in the premium segment. However, most of today’s machines have a total efficiency of less than 10%, meaning that only a fraction of the energy in fuel is actually converted into mechanical power. Low efficiency is mainly caused by inefficient operation of the engine and throttling losses across hydraulic valves.
To date, the simple and most-popular solution in industry has been to optimize only the hydraulics. Such an approach does offer some improvement but, unfortunately, neglects the importance of the engine and its effects on efficiency of the entire machine.
In contrast, the new STEAM mobile-hydraulic system for excavators represents the first holistic approach to optimize both energy efficiency and performance of mobile machinery. In contrast to today’s load-sensing and flow-controlled systems, STEAM does not use the engine and pump to directly supply flow to the actuators but, rather, to maintain pressure levels in two separate hydraulic accumulators (high and medium pressure). This accumulator charging circuit makes it possible to completely decouple the hydraulic actuators from the engine and pump, letting these components operate far more efficiently.
This not only enables operation at a considerably lower and quieter engine speed of 1200 rpm but also minimizes throttling losses and permits recovery of both potential and kinetic energy from all the actuators. Consequently, the machine is considered a hydraulic hybrid.
In contrast to other hybrids, STEAM does not use electrical storage devices or actuators. The already installed hydraulic system only needs to be modified, which keeps costs low and avoids unnecessary energy conversions. The robust and easy-to-maintain hydraulic hybrid technology reportedly increases profitability for operators, as they can expect a more agile machine with significantly lower fuel consumption. Considering the constant concern over fuel costs and more-stringent emission guidelines, STEAM is clearly a very relevant and possibly game-changing innovation for the construction equipment industry.
The prototype is currently being tested with preliminary measurements showing that the hybrid is just as fast and powerful as standard machines, but it operates up to 40% more efficiently. More testing is underway to accurately quantify the potential of the new technology and make the results available to industry, thereby encouraging implementation in future applications.
Harald Gollwitzer GmbH has developed a hydraulic pipe-laying tool that can automatically unload, transport and lay concrete pipes up to 2.2 m in diameter and weighing up to 15 tons, in contrast to current practice of handling huge pipes is with chain suspensions and lifting hoists.
The tool is a U-shape attachment for excavators. Motorized rollers radially align the pipes and hydraulic-powered cardanic pendulum bearings adjust for various pipe lengths. Further, a hydraulic pipe truss connects via a belt to the pipe-laying tool and positions pipe sections with millimeter precision.
In the course of laying pipes, the sections are aligned precisely to the necessary slope with the help of the tool’s hydraulic movements. And it adjusts to different pipe lengths or profiles. The pipe-laying tool also equally distributes pressure at suspension points on the pipe collar, which minimizes potential damage.
The device is controlled from the excavator cab. And, according to company officials, tests show that the new tool cuts handling time of pipes in half.
High-stability wheeled excavator
Mecalac has reportedly improved the stability of wheeled excavators. Typically, this type of vehicle, with an oscillating axle on the undercarriage gives the upper carriage an intrinsically high center of gravity. This results in a lack of stability and uneasiness on the part of the operator. On top of this, the inconvenient height of the cab forces the operator to adopt unnatural, sometimes even hazardous, positions.
Mecalac is tackling these issues by lowering the center of gravity on its new MWR wheeled excavator concept. It reportedly results in a machine with the stability of a telescopic loader and the function of a wheeled excavator. It significantly lowers the upper carriage, including the cab, engine and hydraulics, while still permitting full rotation.
The engine and hydraulic pumps are more accessible from the ground without maintenance personnel having to climb onto the machine and posing a safety risk. Access to the cab and fueling is also said to be easier.
Hydraulics on similar Mecalec wheel loaders includes open-circuit hydrostatic transmissions, variable pumps operating to 350 bar, load-sensing and flow sharing proportional valves, and hydraulic motors that swivel the turret 360°.
RWTH Aachen University