Definition
Disc disperser is a kind of mechanical mixing and dispersing equipment widely used in industrial and scientific research fields. Its core function is to shear, impact and turbulence the solid particles in the fluid system through the high-speed rotating dispersion disc, so as to achieve the refinement, uniform dispersion and mixing of particles in the liquid medium. The equipment mainly serves the production and R&D links of coatings, inks, adhesives, nanomaterials, cosmetics and food industries.
Principle
The working principle of the disc disperser is based on the theory of fluid mechanics and mechanical shear. When the motor drives the shaft to drive the dispersion disc to rotate at high speed, the toothed or smooth structure on the edge of the dispersion disc sucks the material from the bottom of the container along the axial direction and throws it radially towards the container wall at a high linear speed. This process generates strong shear and impact forces, and at the same time forms violent turbulence and circulating flow. For suspension systems containing solid particles, mechanical energy can overcome the cohesion force between particles through shear action, destroy the agglomeration structure, and expose the primary particles and gradually be wetted and wrapped by liquid, and finally achieve uniform dispersion at the microscopic scale. The shear rate and dispersion effect of the core can be controlled by adjusting the rotation speed, the geometry of the dispersion disc and the viscosity of the material.
Measurement and evaluation methods
The evaluation of dispersion effect requires a comprehensive analysis of process parameters and final product performance. Online monitoring usually includes measuring torque, power consumption and temperature changes during operation, which indirectly reflects the strength and stability of the dispersion process. For the determination of the dispersion endpoint, samples need to be taken for offline analysis. Common methods include measuring the particle size distribution using a particle size analyzer, the data of which can reflect the degree of aggregate depolymerization; The microscopic morphology and dispersion state of particles were observed by scanning electron microscopy. Measure application performance indicators such as slurry viscosity, settling rate or gloss, color, etc. These test methods are subject to the appropriate national or international standards, for example, the coatings industry may be partially evaluated with reference to the ISO 1524 standard method for grinding fineness.
Influencing factors
The final effect of a disc disperser is affected by a combination of factors. In terms of equipment parameters, the diameter of the dispersion disc, toothed structure, edge line velocity, and its immersion depth and relative position in the container are key variables. Spindle speed, dispersion time, batch volume of the material being processed, and temperature control are critical to the process parameters. The material characteristics constitute the basic conditions, including the particle size, hardness, and concentration of the dispersed phase, as well as the viscosity, polarity, and surface tension of the continuous phase. In addition, the selection and addition of co-dispersants (such as wetting agents and dispersants) can significantly change the interface properties and affect the dispersion efficiency and stability. These factors are interrelated and require system optimization in process development.
Applications
With their efficient dispersion capabilities, disc dispersers play a crucial role in several industrial sectors. In the manufacturing of coatings and inks, it is used to evenly disperse pigments and fillers into resin bases, which directly affects the hiding power, coloring power and stability of products. The adhesive industry uses it to achieve the homogenization of solid additives in colloids. In the field of nanomaterial preparation, it can be used for the pre-dispersion or deagglomeration of nanoparticles in base solutions. In addition, it is used in the cosmetics industry to prepare creams, and in the food industry to make sauces, etc., all of which reflect the versatility of its treatment liquid-solid dispersion system. Its application premise is that the material system is suitable for dispersion by mechanical shearing.
Selection considerations
Choosing the right disc disperser is a systematic project that requires decisions based on specific process requirements and material characteristics. First, it is necessary to clarify the physical properties of the material being treated, such as initial particle size, target particle size, viscosity range, and rheological behavior. Secondly, determine the processing capacity, power range and corresponding motor type of equipment according to the production scale (laboratory R&D, pilot or large-scale production). The material of the dispersion disc (such as stainless steel, carbide) needs to consider wear resistance and corrosion resistance. Safety features of the equipment, such as overload protection, emergency braking, and the need for additional modules such as speed regulation, lifting, vacuum, or heating, should also be evaluated. It is recommended to obtain key data through small-scale process trials to provide a reliable basis for final selection.