2026/06/24
The spraying system of an organic fertilizer disc granulator directly determines the pelletization rate, the tendency for material to stick to the disc, and the quality of the finished granules. Selection should be based on five key factors—nozzle type, water supply pressure, material, layout, and control modules—while accounting for the specific operating conditions of organic fertilizers, such as high moisture content and the presence of impurities like straw.
Nozzles fall into three categories, to be selected based on specific needs. The first is the two-fluid air-atomizing nozzle; paired with a 0.4–0.6 MPa air compressor, it produces fine, uniform droplets. It is ideal for high-fiber organic fertilizers (e.g., those containing straw or fungal residue) as the mist prevents localized pooling and clumping, significantly reducing disc adhesion. While it requires an external air source, it is well-suited for large-scale, stable production lines. The second type is the high-pressure centrifugal atomizing nozzle, driven by a 2–4 MPa pump. It requires no air compressor, offers high cost-effectiveness, and is suitable for pure manure or low-fiber, decomposed raw materials, with simple daily maintenance. Low-pressure direct-stream nozzles must be avoided; their large droplets cause localized over-wetting and mud clumping, leading to a surge in recirculated material. Nozzle materials should preferably be stainless steel or ceramic; plastic nozzles are prone to corrosion and clogging due to the impurities found in organic fertilizer water. An orifice diameter of 1–2 mm is recommended to balance atomization performance with clog resistance.
The matching of water supply pumps and filtration systems is crucial. Small-to-medium discs should use variable-frequency high-pressure pumps, allowing for stepless adjustment of spray volume and switching between granule sizes without stopping the machine; large granulator discs require independent multi-branch water supply systems. A two-stage filter should be installed at the water inlet to trap silt and organic residues, preventing frequent nozzle clogging and downtime. The water storage tank should include a sedimentation zone to ensure a clean and stable water supply.
Nozzle quantity and layout must match the disc specifications. Small discs (under 2 meters) typically require two nozzles, while medium discs (2.5–3 meters) require three to four. Nozzles should be angled toward the core area where material tumbles within the disc, covering the zone where seed granules form, while avoiding direct spraying against the disc wall, which causes adhesion. Adjustable ball valves should be installed in the piping to allow for independent fine-tuning of flow rates for each nozzle, ensuring uniform moisture across the disc surface and eliminating dry or overly wet spots. A simple configuration is suitable only for low-fiber, pure manure feedstocks. However, for disc granulation produciton lines handling high straw content or highly viscous materials—and where a high pelletization rate is desired—a complete dual-fluid atomizing spray system is the preferred choice. When paired with filtration and variable-frequency water supply, this setup minimizes the labor hours required to clean sticky residue from the disc, reduces material loss from recycling, and boosts the equipment's effective production capacity.
