Disc granulator
The disc granulator is an industrial machine that transforms powdery or granular materials into spherical pellets through a rolling-agglomeration process. Utilizing a disc-based pelletizing method that involves pre-wetting the material, it achieves efficient granulation of powders based on a simple yet effective principle. Characterized by a simple structure, intuitive operation, ease of maintenance, a high pelletizing rate, and the production of strong, spherical granules, it serves as an indispensable core component in organic and compound fertilizer production lines.

Structural Composition of the Disc Granulator

The structural design of the disc granulator embodies a balance of functionality and reliability. The main unit comprises the following components:

(I) Granulation Disc: Features a unitary arc-shaped structure welded from steel plate, with the disc bottom reinforced by multiple radial steel ribs. The interior is lined with high-strength fiberglass-reinforced plastic (FRP) for excellent corrosion resistance. The disc is equipped with three discharge outlets to facilitate intermittent production operations.

(II) Drive and Transmission System: Includes an electric motor, a speed reducer, a belt drive mechanism, and a gear set (large and small gears). A flexible belt drive is employed to effectively reduce impact loads during startup. The large gear is fixed to the disc bottom and meshes with the small gear to transmit power.

(III) Support and Adjustment Mechanism: Comprises the main frame, an adjustment disc, and an angle adjustment device. The frame is constructed from welded channel steel, and the transmission assembly utilizes hardened gears to extend service life. An angle-adjustment screw mechanism allows for precise control of the disc's operating inclination.

(IV) Scraper Cleaning System: Includes a scraper mount and a non-powered scraper; these components promptly remove material adhering to the disc walls, ensuring the granulation process proceeds continuously and stably.

Application of the Disc Granulator in the Production Line

The disc granulator serves as the core granulation unit in organic and compound fertilizer production lines. The process flow for a complete disc granulation line is as follows: fermentation turner → crusher → mixer → disc granulator → dryer → cooler → screener → automatic packaging scale; belt conveyors connect the various stages.

Specifically, raw materials such as livestock and poultry manure are first sent to the fermentation area for aerobic fermentation and secondary aging to eliminate odors and decompose coarse fibers. The fermented and decomposed material is then crushed and screened to achieve the appropriate particle size. Next, it enters the mixing system, where N, P, K, and trace elements are added according to the formula and blended thoroughly. The mixture is fed into the disc granulator to form granules. These formed granules are dried to remove moisture and increase strength, then cooled to prevent caking. Finally, the product undergoes screening and classification; qualified products proceed to packaging, while unqualified ones are returned for re-granulation.

The equipment's granulation process

The granulation process of the disc granulator is a typical wet agglomeration method. The entire process comprises three stages:

Stage 1—Raw Material Pre-treatment: Fermented and matured organic fertilizer materials are pulverized to achieve the appropriate particle size (typically 80–120 mesh) and then conveyed to a horizontal mixer for uniform blending according to the formula. The moisture content of the raw materials must be controlled between 25% and 35%; excessive moisture leads to clumping, while insufficient moisture prevents the formation of granules.

Stage 2—Rolling Granulation: The uniformly mixed raw materials are fed at a constant rate into the granulation disc, where they undergo reciprocating motion driven by centrifugal force, friction, and gravity. During this process, water is sprayed evenly via atomization, causing the moistened materials to adhere to one another and grow in size as they roll. The particle size of the finished product can be precisely controlled by adjusting the disc's inclination angle and rotational speed.

Stage 3—Product Discharge: Granules that have reached the specified size naturally overflow from the edge of the disc. Undersized particles are returned to the granulation disc for further processing via a screening and recirculation system, thereby ensuring efficient raw material utilization.

The equipment's fermentation process
While the disc granulator itself does not directly participate in the fermentation process, it serves as a critical link in the post-fermentation material processing chain. In organic fertilizer production, the fermentation process typically precedes granulation. Raw materials (such as livestock and poultry manure) first enter the fermentation zone, where they undergo primary aerobic fermentation and secondary aging (maturing) in piles; during this stage, fermentation microbial agents are added to break down crude fibers. Fermentation temperatures are generally maintained between 50°C and 60°C. Only after the fermented and matured material has undergone drying, crushing, and ingredient mixing does it enter the disc granulator for granulation.

Equipment operating instructions

Standardized operation of the disc granulator is crucial for ensuring granule quality and extending equipment lifespan. The operating procedure is as follows:

Pre-start preparation: Inspect the surface of the granulation disc for flatness, wear, deformation, or cracks; check the tension and lubrication of drive components (belts, chains, gears); verify that motor connections are secure and electrical components are functioning correctly; and ensure the feed and discharge ports are clear of obstructions.

No-load trial run: Start the motor and observe the rotation direction of the granulation disc; check for abnormal vibration or noise, and run the machine without load for 10–15 minutes.

Load commissioning: Feed material slowly, gradually adjusting the granulation disc's rotation speed and inclination angle based on material characteristics. Typically, for organic fertilizer raw materials, the rotation speed is controlled at 15–20 rpm and the inclination angle is set between 45° and 55°. Regulate water addition evenly using an atomizing spray.

Operational monitoring: Closely monitor granule formation during operation. If there is an excess of fine granules, appropriately increase the water supply or reduce the rotation speed; if large clumps form, reduce the feed rate and clean the disc walls.

 Equipment Application Results and User Feedback
In actual production, the disc granulator demonstrates outstanding performance. Organic fertilizer manufacturers report that using the disc granulator significantly improves the roundness of the finished granules, leading to high market acceptance; compound fertilizer producers note the equipment's stable operation, robust continuous processing capabilities, and low maintenance costs. Overall, the disc granulator has gained widespread recognition across various industries due to its reliability and cost-effectiveness.