Composed of a motor, reducer, and gear pair (drive gear + drum ring gear), it provides stable rotational power for the drum. Unlike chain-driven drum granulators, the gear transmission ensures a more consistent rotation speed (typically 10–20 rpm) and higher torque, avoiding speed fluctuations that cause uneven granule sizes.
A horizontally placed cylindrical drum with a slight incline (3°–5°) to facilitate the slow movement of materials from the feed end to the discharge end. The inner wall of the drum is often equipped with lifting plates (also called “抄板” in Chinese) — these plates lift materials as the drum rotates and then them, promoting full mixing and collision of materials to form granules.
Includes roller supports (to bear the weight of the drum) and a sealing device (at the drum’s feed and discharge ends) — the latter prevents dust leakage or material spillage during operation, ensuring a clean working environment.
A receiving hopper or conveyor belt installed at the drum’s discharge end collects the formed wet granules and transports them to subsequent processes (e.g., drying, screening) for further treatment.
Powdery or semi-wet raw materials are continuously fed into the rotating drum. Under the action of the drum’s rotation and internal lifting plates, the materials are fully mixed and evenly distributed inside the drum. If a binder is used, it is sprayed synchronously and mixed with the materials to adjust their humidity and viscosity.
As the drum rotates, the materials are repeatedly lifted and dropped. During this tumbling process, fine powder particles collide and adhere to each other, forming small “seed nuclei” (initial small granules). The stable rotation speed (maintained by the gear system) ensures that the collision force between particles is uniform, avoiding overly loose or overly dense seed nuclei.
The small seed nuclei continue to collide with surrounding powder particles during tumbling, gradually absorbing more powder and growing into larger granules. The lifting plates and the drum’s incline help shape the granules into spherical or oval forms (with a typical diameter of 2–6 mm). The gear transmission’s consistent speed prevents excessive granule growth or breakage caused by sudden speed changes.
When the granules reach the desired size, they move to the drum’s discharge end under the combined action of the drum’s incline and rotation, then fall into the receiving hopper. The entire process is continuous, with a stable granulation rate (generally 70%–85%, depending on raw material properties).
The large inner volume of the drum (common specifications: diameter 1.2–2.5 m, length 3–6 m) and continuous operation design allow it to handle 5–50 tons of raw materials per hour, meeting the needs of large fertilizer factories.
The gear-driven stable rotation and internal lifting plates ensure that materials are tumbling and mixing evenly, resulting in spherical/oval granules with a uniform size distribution (qualified rate of 80%–90%), which improves the appearance and marketability of finished fertilizers.
It can process a variety of raw materials, including organic fertilizer (decomposed manure, straw powder), compound fertilizer (nitrogen-phosphorus-potassium blends), and mixed fertilizer (organic-inorganic blends). It also adapts to slight variations in raw material moisture (20%–40%) by adjusting the binder amount.
The gear transmission system has fewer wearing parts (compared to chain drives, which require frequent chain replacement), and the drum’s inner lifting plates are made of wear-resistant steel (e.g., Mn13), extending their service life. Daily maintenance mainly involves checking gear lubrication and cleaning the drum inner wall, which is easy to operate.
