The new DL420-7 is working in the Węsiory quarry, one of several businesses run by the Wroński Group connected with the construction industry. Founded in 1992, the company’s operations cover all of the territory of Pomeranian Voivodeship in Poland. The Wroński Group currently carries out general construction works and runs three building materials warehouses and a prefabricated products plant as well as the quarry, from which it obtains raw materials.
“We know the Doosan brand very well. The first machines in our fleet were two DL400s, which to this day are still used for smaller jobs," recalls managing director, Mateusz Wroński.
The company has always been focused on developing the business with regular investments in new equipment and in 2015, the Wroński Group management began discussions with Grausch and Grausch Maszyny Budowlane, the Authorised Doosan dealer for Poland.
“At that time, they offered us a new generation machine to test out, specifically the DL420-5 model. We were amazed by the speed and efficiency when working with the machine. The reduction in fuel consumption was so big compared to our old machine, that the money we saved allowed us to pay the leasing instalment,” Wroński explains.
After the successful test, the machine never left the quarry in Węsiory, where it continues to work without any problems to this day and has achieved an amazing 18,000 hours of problem-free work. “So, in 2020, when we wanted to buy a new wheel loader, we immediately knew it would be a Doosan," adds Wroński.
The need to purchase a new machine coincided with the introduction of the new generation of Doosan DL-7 wheeled loaders. The existing products have been completely redesigned, and the number of standard functions on the machines again exceeds those on competing models. The company chose a new DL420-7 loader, which with an operating weight of 23.4 tonne, is one of the larger models in the new Doosan DL-7 range.
The DL420-7 is powered by a Scania DC13 6-cylinder engine producing 257kW of engine output at 1800 RPM. The new engine meets Stage V emission regulations without the need for exhaust gas recirculation (EGR), through the use of selective catalyst reduction, diesel oxidation catalyst and diesel particulate filter (DPF) after-treatment technologies. The soot cleaning cycle on the DPF has been improved to over 6000 h and the operator is fully informed about the status of the DPF via a soot level indicator on the new touchscreen display in the cab.
With no EGR valve and a choice of three power modes (SAT2, Standard or Power), fuel consumption is reduced by 5%. The machine performs very well in difficult terrain, thanks to another standard feature, the hydraulic differential lock (HDL), which is activated automatically at full torque without any additional action from the operator.
The five-speed PowerShift transmission gives the driver the option of three modes: manual, automatic or semi-automatic. A torque converter lock is also standard equipment, which significantly reduces fuel consumption during passes. The lift arm with Z-kinematics provides impressive breakout power and lifting capacity, while the large drop angle allows for efficient unloading.
The LIS (Load Isolation System) provides a smoother ride and higher comfort for the operator, as well as higher productivity due to improved stability when the wheel loader is moving. Following the supplier's recommendation, the bucket capacity has been increased from 4.3 to 4.5m³ and the blade has been fitted with rounded edges and a higher spill guard. This makes loading even more efficient and has a direct impact on reducing cycle times and increasing productivity.
“Our wheeled loaders are mainly used to pick up material from the quarry face and to load trucks. I can safely say that with the DL420-7 the work has become much faster, and the machine never lacks power. The loader is very stable, the hydraulics are smooth, which provides dynamic movements. The ability to control the direction of travel with the joystick is especially praiseworthy, especially when the work requires repetition of the same manoeuvres, for me this hits the bull’s eye for loader operation. The operator comfort has certainly increased, the protection against shocks is clearly noticeable, especially when you are working a 10-hour day. Another important improvement for me is the easy access to filters and components, which means that daily maintenance requires a minimum of effort,” mentions operator, Rafał Pawłowski.
The operator's cab is spacious, and the steering is electrically controlled. All settings and information can be accessed via an intuitive 8-inch touchscreen, which is easy to read in all conditions. Safety was one of the most important aspects when designing the
DL-7 loaders. The operator's field of vision is increased by enlarged windows, and LED work lights in a 4 front, 4 rear configuration provides excellent illumination, especially in the winter months.
“We work with relatively light material, such as sand, gravel and stone, but the quarry is quite steep and the terrain is bumpy, which means the machine is heavily laden during loading. With this workload, the average fuel consumption of 13 l/h is a very good result. Since the delivery of the machine, we have used it for more than 2500 hours without a hitch, so I consider this to be an extremely successful investment. I am glad that I was the first in Poland to have the opportunity to test the capabilities of this excellent machine. When I choose Doosan, I get quality at a reasonable price. Without compromises," sums up Wroński.
Like all Doosan DL-7 wheeled loaders, another advantage offered by the DL420-7 is the factory-installed wireless fleet management system, DoosanCONNECT TMS 2.0, which provides extensive information about operating parameters, including work efficiency, via satellite and mobile networks. The standard warranty on all Doosan DL-7 loaders is 36 months/5000 hours, whichever comes first.
