Climb into the operator's station of Bomag's new BW161AD-4 HF tandem vibratory roller, and one of the first features of its all-new design to arrest your attention is the wide-open visibility to the drums and sprinkler nozzles.
The view results from using slanted drum-support legs, and, from tucking the new water-cooled Deutz engine beneath the operator's station, not in the rear frame as with its predecessor model, the BW161AD-2. With the engine thus repositioned, Bomag could shape the water tank (rear frame) and the radiator cover (front frame) to allow an enhanced view to drum surfaces, drum edges and spray bars.
The operating weight of the BW161AD-4 HF (HF for "high frequency") is around 21,800 pounds—about 1,000 pounds more than that of its predecessor. And, although the two models differ considerably in design, the company did carry over into the new model what it considered good, fundamental technology in its predecessor. Retained features include dual-amplitude/dual-frequency capability, independent control of drum vibration, articulated steering with 6.7 inches of drum offset and a sliding, swiveling seat in the cabin with two steering wheels.
But much also is changed in the new machine. Its water-cooled, four-cylinder Deutz engine has 131 horsepower, compared to 113 for the air-cooled version of the Deutz engine used in its predecessor. And at the very heart of the machine, the centrifugal force it develops in both low and high amplitudes is significantly greater. Low-amplitude force is 27,225 pounds, compared to 17,010 pounds in the old model; and 36,000 pounds in high-amplitude, compared to 29,115 pounds. While high-amplitude frequency remains the same between the old and new models at 2,700 vpm, low-amplitude frequency is considerably increased, from 3,000 to 3,600 vpm.
The new model's water system also retains its predecessor's easy-to-clean, pop-out spray nozzles, as well as the six-position, spray-interval timing system that conserves water. New for the BW161AD-4 HF, however, is a second water pump—a backup—capable of handling the pressurized-water requirements of the machine. The predecessor model relied on a gravity-feed backup system.
As an option, the new model can be fitted with Bomag's Asphalt Manager system, which employs an "asphalt-stiffness" measuring technology to gauge the degree of compaction. The system, says Bomag, "automatically measures and controls the compaction performance of the roller," and it also can be equipped with a printer.