South Korean industrial equipment conglomerate Doosan celebrates its twentieth year in South Africa this year, notes Disa Equipment MD Rod Watson, adding that Doosan maintains its strong position in today’s competitive earthmoving sector through its reputation for reliable engines, a robust chassis structure, high-quality components and features.
Disa Equipment trades as Doosan and forms part of the Capital Equipment Group of Invicta Holdings.
“What’s critical to Doosan’s success is the technical support and repair and maintenance service we offer our customer base throughout the country. Doosan equipment is also supported by extended warranties,” comments Watson, adding that the company’s commitment to meeting exact market requirements includes the launch of new machines designed to cope efficiently and safely in African conditions.
Doosan earthmoving equipment encompasses track, wheel and mini excavators, articulated dump trucks, as well as wheel loaders and various attachments.
A leading machine in the range is the heavy-duty Doosan DX225LCA hydraulic excavator series – one of the biggest size classes of equipment in South Africa. Watson explains that these excavators are known for improved fuel efficiency, enhanced productivity, minimal maintenance requirements and greater operator comfort.
The DX225LCA series has notable design features, especially for the African market, with advantages over other machines in the same size class of equipment.
“These features include a reliable six- cylinder water-cooled engine that is optimised and electronically controlled to boost production, increase fuel efficiency and ensure harmful emissions remain well below the values required for Tier II engines. This machine boasts the most efficient fuel consumption of this size class of equipment, consuming less fuel for the same production,” comments Watson.
Further, the heavy-duty boom and arm have increased material thickness, which limits element fatigue, increasing reliability and extending component life.
This series also has a longer undercarriage than competitor machines. “Although a shorter undercarriage reduces manufacturing costs, stability of these machines is compromised. All welded structures of the Doosan undercarriage have been designed to limit stresses,” says Watson.
He explains that the lateral chassis is welded and rigidly attached to the undercarriage. Tracks locked by mechanically bolted pins are composed of sealed, self- lubricating links, which are isolated from external contamination for dependability in all conditions. The hydraulic track adjuster has a shock absorbing tension mechanism.
The DX225LCA series has standard hydraulic piping for hammer applications and an improved H Class bucket. These machines are supported by Doosan through a two-year/4 000-hour warranty.
The swing mechanism – an axial piston motor with a two-stage planetary reduction gear – offers increased swing torque at reduced swing times. The maximum swing speed is 11 rpm.
The hydraulic excavator’s 21.5 t operating weight is enhanced by new specifications that include a 0.92 m3 bucket capacity, a digging depth of 5 755 mm, a digging reach of 8 950 mm and a digging height of 9 750 mm. The engine rated power is 110 kW at 1 900 rpm. Maximum engine torque is 638.41 Nm or 1 400 rpm.
Additionally, “the electronic power optimising system (e-pos) provides a perfect synchronised communication link between the engine’s electronic control unit and the hydraulic system. A controller area network system facilitates a constant flow of information between the engine and hydraulic system, ensuring power is delivered exactly as it is needed”, adds Watson.
He also states that tests have shown that these machines have the industry’s best traction force – for their machine weight – when working on a slope or in tough ground conditions.
“This hydraulic system enables independent or combined operations. The two travel speeds offer either increased torque or high-speed tracking . . . the auto deceleration system and cross sensing pump ensure fuel savings,” Watson enthuses.
The multifunction colour liquid crystal display monitor panel has standard features for simple control and efficient operation. These controls include mode selection, precise flow-rate regulation, auto deceleration and display selection. Maintenance and oil change intervals can be displayed, a self- diagnosis function allows technical problems to be quickly resolved and an operational memory provides a graphic display of the machine’s status.
Levelling operations, movement of lifted loads and tricky manoeuvres are all controlled easily and precisely with control levers. Buttons integrated on the levers are used to operate additional equipment, like grabs, crushers and grippers.
“Doosan’s DX225LCA machines have been designed with the latest ergonomics, which enhance efficient operation, improve safety and offer greater operator comfort for reduced fatigue. New features include a spacious, all-weather sound-suppressed cab with a clear all-round view, effective air conditioning and an adjustable seat, with an optional air suspension system to reduce vibrations.” Further, Watson points out that there are large handrails and a wide step with antislip plates, right and left rearview mirrors, a travel alarm and safety glass for improved operator safety.
“This series has been designed for easy maintenance and reduced downtime. A computer-based monitoring function enables connection to the e-pos control system. Various parameters can be checked during maintenance, including pump pressure, engine rotation and engine speed. This information can be stored and printed for analysis,” explains Watson.