Definition
A laboratory power disperser is a mechanical equipment used to efficiently mix, disperse, homogenize, and dissolve liquid, semi-fluid, or paste-like materials. It produces strong shear, impact and turbulence through the high-speed rotating dispersion disc, so that the solid particles or droplets in the material are refined and evenly distributed in the continuous phase, so as to achieve the ideal dispersion effect. This equipment plays a key role in laboratory research and sample preparation in various fields such as chemicals, coatings, inks, food, cosmetics, and new material research and development.
Principle
The core working principle of the laboratory power disperser is based on the shear and turbulence effects in fluid mechanics. The equipment is usually composed of a motor, a drive shaft and a dispersion disc (or impeller). When the motor drives the dispersion disc to rotate at high speed, the linear velocity of the edge of the dispersion disc is high, which generates a strong shear force on the surrounding material. At the same time, the material is sucked under the dispersion disc at high speed and thrown towards the container wall along the radial direction, forming a strong circulation flow and turbulence. In this process, agglomerated solid particles or immiscible droplets are crushed, refined, and evenly dispersed in the medium under continuous mechanical force. The dispersion effect can be characterized in part by the shear rate, which is related to the rotation speed and geometric size of the dispersion disc, which can be used as a formula γ = (π * D * N) / 60 * h Approximately, where γ is the shear rate, D is the diameter of the dispersion disk, N is the rotational speed, and h is the characteristic clearance distance.
Measurement and evaluation methods
Evaluation of dispersion often relies on quantitative testing of the performance of the final product. Common methods include particle size distribution analysis, which uses a laser particle size meter to measure the particle size and its distribution width to determine the uniformity and refinement of the dispersion. For emulsion systems, dispersion stability can be evaluated by observing the aggregation or stratification of droplets with a stability analyzer. In addition, viscosity measurement, gloss measurement and color uniformity observation are also auxiliary evaluation methods. In practice, process parameters (such as dispersion time, final viscosity) are often associated with product performance indicators to form a reproducible process evaluation scheme.
Influencing factors
The dispersion effect is affected by multiple factors. In terms of equipment parameters, the diameter, shape, tooth structure and rotation speed of the dispersion disc directly affect the shear strength and flow field distribution. The geometry and dimensions of the vessel need to be matched to the dispersion disc to create an effective circulating flow field. Dispersion time is the basic factor in process parameters, but it needs to be coordinated with the rotational speed to avoid excessive dispersion leading to high system temperature or unnecessary physicochemical changes. Material properties are particularly critical, including the viscosity of the continuous phase, the concentration of solid particles, the initial particle size and surface properties, and the selection and dosage of dispersants. Environmental conditions such as operating temperature can also affect the viscosity and dispersion process of the material, which usually need to be controlled within a certain range.
Applications
Laboratory power dispersers are widely used. In the coatings and inks industry, it is used for pre-dispersion of pigments and fillers and formulation research and development. In the food industry, it can be used for the homogenization of samples such as sauces and dairy products. In the field of cosmetics, it is commonly used to prepare creams, lotions and other samples. In the laboratory research of emerging materials such as nanomaterials, battery slurries, and adhesives, the powerful disperser is the basic equipment for formulation optimization and process exploration. Its versatility makes it a common tool for liquid-solid or liquid-liquid mixing and dispersion studies in many industry laboratories.
Selection considerations
When choosing a power disperser for your lab, you need to consider a lot of things. First of all, the properties of the main materials to be processed, such as viscosity range, corrosiveness, whether they contain volatile solvents, etc., are related to the choice of equipment material (such as stainless steel, carbon steel) and sealing method. Second, determine the appropriate power and capacity specifications according to the batch processing volume required for the experiment. The speed regulation range of the disperser should cover the process requirements from low-speed mixing to high-speed dispersion, and the stepless speed regulation method can provide more flexible operation. In terms of safety, attention should be paid to the overload protection, mechanical stability and electrical safety certification of the equipment. In addition, the ease of cleaning, noise level, abundance of accessories (e.g., multiple dispersion discs, replaceable containers), and support for data logging capabilities are also important aspects of improving experimental efficiency and reproducibility.