Overview: The Dry-Forming Revolution Without Binders

In industries such as fertilizers, metallurgy, chemicals, and ceramics, directly converting powdered materials into high-strength, regularly shaped granules has always been a critical production step. The hydraulic roller press granulator, an outstanding representative of modern dry-forming technology, abandons the complex steps of adding water, binders, or applying heat required in traditional granulation processes. It relies purely on immense mechanical pressure to “cold-press” dry powder into dense sheets or pillow-shaped briquettes through a pair of precisely matched rollers, which are then crushed and screened to obtain uniform granules. This technology, characterized by high efficiency, energy savings, and high product purity, is leading a quiet revolution in the field of solid-state forming.

Core Principle: The Scientific Fusion of Pressure and Mold

The working principle of a hydraulic roller press granulator is essentially the engineering application of hydrostatic pressure forming. The process involves no chemical changes, only a physical transformation o

Detailed Four-Step Forming Process:

Controlled Feeding: Precisely metered dry powder is fed evenly and continuously into the nip area between two parallel rollers via a screw feeder or gravity feeder.

High-Pressure Compaction: This is the core step. Driven by a powerful hydraulic system, two counter-rotating rollers (one fixed, one horizontally floating) apply an extremely high linear pressure (typically 50-300 MPa) to forcibly compact the captured powder. The material undergoes three zones within the roller gap (roll nip):

Feed Zone: Material is drawn in.

Compression Zone: Pressure increases dramatically, air between particles is expelled, and the particles themselves undergo plastic deformation or brittle fracture, bonding tightly together through intermolecular forces.

Forming Zone: The material reaches maximum density and is pressed into a continuous sheet with a specific shape (e.g., oval, pillow-shaped) according to the pockets  engraved on the roller surface.

Demolding & Discharge: The formed sheet naturally detaches from the pockets as the rollers rotate and discharges under gravity.

Crushing & Sizing: The discharged continuous sheet is usually very dense and needs to be fed into a chain crusher or fine breaker for gentle. It is then screened by a vibrating screen to separate granules meeting the size requirements. Oversized particles return to the crusher, while undersized fines are recycled back to the feeding system, forming a closed-loop production.

Core Structure: The Vessel of Force and Precision

A high-performance hydraulic roller press granulator is a complex mechatronic and hydraulic integrated system:

Roller Assembly: The core working component.

Rollers: Typically made of high-hardness, high-wear-resistant alloy steel (e.g., 60CrMnMo), with surfaces specially heat-treated (e.g., quenching, carburizing). The roller surface is machined with precisely arranged pockets, whose shape and size directly determine the of the finished granules.

Accumulators: Used to cushion pressure shocks, maintain stable rolling pressure, and protect mechanical components.

Control System: Through pressure sensors and PLC, it enables precise pressure setting, automatic compensation, and overload protection. This is key to ensuring stable forming quality and operational safety.

Drive System: Consists of the main motor, reducer, gearbox, and universal joints, driving the two rollers to rotate synchronously and counter-rotating.

Feeding System: Ensures material is fed evenly, stably, and adjustably into the roll nip, preventing and pressure fluctuations.

Electrical Control System: Integrates automated control for one-touch start/stop, parameter setting, fault diagnosis, and data logging.

Performance Advantages: Why Choose a Hydraulic Roller Press?

Compared to traditional wet or semi-wet processes like drum granulation,or pan granulation, hydraulic roller press granulators hold overwhelming advantages in specific application scenarios:

Comparison Dimension	Hydraulic Roller Press (Dry Process)	Rotary Drum Granulator (Wet Process)
Process Principle	High-pressure dry compaction, pure physical process	Liquid-phase bonding + rolling agglomeration, physico-chemical combination
Product Characteristics	High granule density, great strength, controllable dissolution, no internal pores	Porous granules, lower strength, fast dissolution
Raw Material Requirements	No need for binders or water, high product purity	Requires water or binders, may introduce impurities
Energy Consumption	Very Low, only requires mechanical energy, no drying process	Very High, requires evaporating
Environmental Impact	No wastewater or exhaust gases, green	Potential process wastewater and dust emissions
Suitability	Suitable for heat-sensitive, moisture-sensitive, or slow-release materials	Suitable for, fast-dissolving fertilizers or chemicals

Summary of Core Advantages:

Exceptional Product Performance: Produces granules with high true specific gravity and extremely high mechanical strength (up to 20-50N), long-distance transport, mechanical application, and fertilizers requiring slow release (e.g., controlled/slow-release fertilizers).