¦PELLET driven through a die under extreme pressure and cut to length. Material is forced completely through the die by new material entering the other end of the die. It is here that the commonalities end and the differences between pellet presses begin to become evident. While subtle variations abound from manufacturer to manufacturer, generally pellet presses can be distinguished from one another in two ways. The first is the means by which power from the motors is delivered to the pellet press. The second is the shape of the die itself.
Gear Driven vs Belt Driven All pellet presses rely on horsepower generated by large electric motors. The manner in which this power is delivered to the press itself is where the differences can be found. The power from these motors is transferred either by gears or a belt. Both gear-and beltdriven pellet presses can be found throughout the industry, and the manufacturers of each stand ready to articulate the value of their approach. “We are a gear-driven pellet mill,” says Anderson. “Some customers, many users, have a feeling that a gear drive is a less desirable design than a belt drive design. That’s a situation that we frequently have to overcome. We talk about the robustness, the lower overall maintenance cost of a single reduction gear drive, versus the cost of
GRAVITY IS GOOD: This schematic of an Amandus Kahl flat die pellet press illustrates how this particular configuration utilizes gravity to bring new material into the pellet chamber. Unlike with a ring die, the rollers on a flat die move around the die forcing the incoming material into and through the die. PHOTO: AMANDUS-KAHL
AN EYE ON ROLL WEAR: Bliss Industries Inc. has continued to refine its deflector design inside the pelleting chamber to ensure that each roll processes the same amount of incoming material. This not only prolongs roll life, but it synchronizes wear so that all rolls need replacement at the same time, limiting down time. PHOTO: BLISS INDUSTRIES INC.
22 BIOMASS MAGAZINE | AUGUST 2014