Double Roller Press Granulator

Description of Double Roller Granulator: 

A double-roller extrusion granulator, also known as a roller press granulator, is a molding machine that uses a pair of opposing rotating extrusion rollers to directly press powdered materials into granules of a specific shape under high pressure. China’s first twin-roll extrusion granulator was successfully developed in 1986; the production process is characterized by ambient-temperature operation, the elimination of drying and binder addition, energy efficiency, environmental friendliness, and low investment costs.

This equipment utilizes a drying-free, ambient-temperature process to achieve granulation in a single step. It eliminates the need for the expensive dryers and coolers required in traditional processes, instead utilizing the material's inherent water of crystallization or a minimal amount of moisture for forming, thereby reducing energy consumption by 30% to 50% compared to conventional methods. The twin-roll extrusion granulator offers great operational flexibility and a wide range of applications, with extrusion pressure adjustable via hydraulic force. It features a scientifically sound design, requires low investment, yields quick returns, and delivers strong economic benefits.

Structural Composition of the Double-Roller Press Granulator：

The double-roller extrusion granulator consists of four main components:

1. Frame Assembly: All working components are mounted on the frame, which is constructed from welded medium-carbon steel plates and channel steel to ensure structural strength and operational stability.

2. Transmission Assembly: Comprising an electric motor, pulleys, V-belts, a speed reducer, chains, sprockets, and couplings. The motor drives the pulley, and power is transmitted through the reducer to operate the granulating head; a separate chain-and-sprocket drive transmits power to the crushing and separation section. A nylon pin coupling connects the reducer output to the granulating head assembly to transmit drive power.

3. Granulating Head Assembly: Power is transmitted from the drive pulley through a pin coupling to the roller shaft; synchronized rotation of the twin rollers is ensured by a pair of open gears. Core components include the bearing housing, a pair of high-pressure roller shells, and two shafts. The rollers are made of high-strength alloy steel, featuring specially shaped cavities on the surface to enhance material gripping. Custom spherical mold cavities are evenly distributed across the roller surfaces to form the granules.

4. Crushing and Separation Assembly: After extrusion, the material flows into the crushing chamber located below. Rotating dual-shaft "spiked rollers" (or "club-shaped" crushers) separate the formed granules from the ungranulated material (fines/returns). This section consists of bearing housings, crushing rollers, and screening mesh. Granular products are obtained through the processes of crushing, shaping, and screening.

Application Scope of Double-Roller Press Granulators：

The double-roll extrusion granulator offers broad material adaptability, making it suitable for granulating a wide range of raw materials used in compound fertilizers, pharmaceuticals, chemicals, and animal feed, while achieving a high granulation rate. It is capable of producing various types and concentrations of compound fertilizers, including organic, inorganic, bio-organic, and magnetized fertilizers. It is particularly effective for granulating compound fertilizers based on rare earth elements, potassium, and ammonium bicarbonate.

Specific materials that can be processed include: granules for capsule filling, pigments, detergents, catalysts, strontium carbonate, chemical fertilizers, silica black (precipitated silica), inorganic salts, chlorinated isocyanurates, bleaching powder, pesticides, and oxides, as well as industrial dusts such as those from cast iron plants; lead, zinc, and aluminum dust; converter dust; filter dust; and grinding dust.

Working Principle of the Double-Roller Press Granulator：

The equipment operates as follows: an electric motor drives a belt and pulley system that transmits power through a speed reducer to the drive shaft; split gears then synchronize the drive shaft with the driven shaft, causing them to rotate in opposite directions. Material is fed into the hopper, where it is extruded and molded into briquettes between the twin rollers. These briquettes are transported via a chain conveyor to a crushing chamber, where they are broken down; finished granules are separated by screening, while undersized material (fines) is recycled and mixed with fresh raw material for re-granulation. Continuous motor rotation and material feeding enable mass production.

The process principle of dry extrusion granulation is as follows: dry material is agglomerated under pressure into dense, hard masses (known as "cakes" or "sheets")—a stage called extrusion; these cakes are subsequently crushed and screened into granules—a stage called granulation. The extrusion process serves two purposes: first, to expel air from between the particles; and second, to bring the particles close enough together to generate intermolecular forces, such as van der Waals forces, adsorption forces, crystal bridges, and interlocking connections.
Target Audience for Double-Roller Press Granulators：
The double-roll extrusion granulator primarily targets the following user groups: fertilizer processing enterprises (including organic, compound, and blended fertilizer plants), feed production facilities, and chemical industry enterprises engaged in powder granulation. It is particularly well-suited for production scenarios requiring an increase in product bulk density. Additionally, it is highly applicable to sectors such as rare earth processing, metallurgy, coal, biological agents, and environmental protection engineering.