What is the main mechanism by which the Industrial High Speed ​​Disperser generates dispersion

The Industrial High Speed Disperser (HSD) stands as a foundational piece of equipment in sectors such as fine chemicals, coatings, inks, and adhesives. Its primary function is the uniform and stable dispersion of solid powders or immiscible liquids into a continuous liquid phase, yielding high-quality suspensions or emulsions. Understanding the kinetic mechanisms that drive the HSD's highly efficient dispersion is essential for process optimization and achieving superior product quality.

I. High-Speed Impeller: Vortex and Macro-Circulation

The principal working component of the High Speed Disperser is the Saw-tooth Disc Impeller, which rotates at extremely high velocities. This rapid rotation first induces a violent vortex and large-scale macro-circulation (Bulk Flow) within the liquid batch.

1.1 Vortex Formation and Powder Incorporation

As the impeller spins at speeds of several thousand revolutions per minute (RPM), it generates significant centrifugal force. This force drives the liquid outward toward the vessel wall, forming a deep, stable funnel-shaped vortex above the impeller. The vortex center pulls the liquid surface down close to the impeller's edge. Powder materials or droplets targeted for dispersion are charged directly into this vortex, leveraging the liquid’s rapid turnover and suction to pull the solid particles quickly into the high-shear zone—the impeller's periphery. Effective management of the vortex is the first critical step in ensuring powders are rapidly wetted and enter the shear zone for agglomerate breakdown.

1.2 Macro-Circulation and Material Renewal

The macro-circulation generated by the impeller ensures that all material within the dispersion tank is continuously drawn into the high-energy area near the impeller for processing. This top-to-bottom and wall-to-center flow pattern promotes overall batch uniformity. Even in systems with slightly higher viscosity, proper setting of the impeller position and speed ensures the macro-circulation effectively prevents the formation of dead zones or stratification at the tank bottom or walls, guaranteeing batch consistency.

II. High-Speed Tip Shear: The Core Dispersion Mechanism

2.1 Kinetic Energy Transfer at Extreme Velocity

The impeller's high rotational speed transfers massive kinetic energy to the liquid in the vicinity of the tip. According to fluid dynamics, the fluid velocity near the tip is proportional to the impeller's linear velocity. This extreme velocity difference creates a drastic velocity gradient within the fluid layers.

2.2 Turbulence and High-Frequency Impact

In the impeller's immediate edge zone, the fluid exists in a state of intense turbulence. Once solid agglomerates are drawn into this region, they are subjected to high-frequency, high-intensity impact and friction from the impeller teeth and the high-velocity liquid. This mechanical force overcomes the inter-particle forces, such as Van der Waals Forces and Electrostatic Forces, causing the agglomerates to instantly break down into smaller primary particles or secondary aggregates. This is the core method by which the HSD achieves deagglomeration and particle size reduction.

2.3 Shear Stress and Agglomerate Rupture

As fluid flows rapidly past the impeller teeth, immense shear stress is created between fluid molecules and between the fluid and the particles. Shear stress is the primary force required to overcome the internal cohesive strength of the agglomerates. Professional industrial HSDs are engineered to produce the critical shear force necessary to shatter most pigment and filler agglomerates. This shearing action is vital for uniform dispersion and the formation of a stable suspension system. Dispersion is only effective when the shear stress exerted exceeds the binding strength of the agglomerate.

III. The Three Phases of Dispersion: Wetting, Deagglomeration, and Stabilization

The operation of a High Speed Disperser is a continuous energy input process, which can be broken down into three phases that collectively achieve high-quality dispersion.

3.1 The Wetting Phase

This is the initial phase of the dispersion process. The powder is rapidly incorporated into the liquid phase. The HSD's macro-circulation and vortex ensure thorough contact between the powder surface and the liquid medium. The liquid film on the impeller surface instantaneously penetrates the voids between the powder particles, displacing air and completing the process of wetting.

3.2 The Deagglomeration Phase

This is the phase where energy input is most concentrated. Under the combined high shear and turbulent impact at the impeller edge, agglomerates are rapidly broken down. The efficiency of this phase directly determines the final product's Particle Size Distribution (PSD) and the total dispersion time required.

3.3 The Stabilization Phase

Following particle breakdown, stabilizers such as resins, dispersants, or surfactants in the liquid rapidly adsorb onto the newly exposed particle surfaces. These stabilizers prevent the particles from re-aggregating, or flocculating, by providing Steric Hindrance or Electrostatic Repulsion. The continuous, uniform mixing action of the High Speed Disperser assists in the homogeneous distribution and full adsorption of these stabilizing agents throughout the system.