Definition
An experimental disperser is a mechanical device used to efficiently disperse, mix, homogenize, or deagglomerate solid particles in liquids, semi-fluids, or slurries under laboratory conditions. Its core function is to break the agglomeration state between particles by applying high shear force, so that they are evenly and stably distributed in the continuous phase, forming a dispersion system. The equipment plays a key role in laboratories in many non-medical fields, such as materials science, coating research and development, food testing, new energy battery slurry preparation, and cosmetic formulation research.
Principle
The working principle of the experimental disperser is mainly based on the high shear action generated by the rotor-stator structure. The motor drives the rotor to rotate at high speed in the stator chamber, creating a powerful centrifugal force. Material is sucked into the rotor area from the bottom or side of the equipment, subjecting it to severe mechanical shear, hydraulic shock, and hole effects in tight gaps. This combined effect effectively breaks up the agglomerated solid particles and mixes them well with the liquid phase medium. The shear rate of its core is related to the rotor line velocity, which can be roughly described by the following relationship:
γ ≈ π D n / h
where γ represents the shear rate, D is the rotor diameter, n is the rotor speed, and h is the gap width between the rotor and stator. Higher rotational speeds and more precise clearance designs often result in higher shear strength.
Main measurement and evaluation methods
The evaluation of the dispersion effect should be combined with the performance indicators of the final product. Process monitoring focuses on dispersion time, input energy (often indirectly reflected by power consumption), and temperature rise control of materials. The evaluation of the dispersed sample needs to be completed with the help of other analytical instruments, such as using a laser particle size analyzer to measure the particle size distribution to evaluate the deagglomeration effect. The rheological characteristics of the system were determined by viscometer. Observe or measure the sedimentation stability, gloss or color of the sample to judge the long-term uniformity and stability of the dispersion system. These methods are carried out in accordance with industry-specific standards (e.g. ASTM standards for the coatings industry, corresponding test specifications for the battery industry).
Performance Factors
The dispersion effect is affected by multiple factors. In terms of equipment parameters, the design form of the rotor (e.g., tooth shape, shear head shape), speed range, power, and the accuracy of the stator and rotor clearance are key. Process parameters include the duration of the dispersion process, the order of batch feeding, and temperature control during the dispersion process. The material properties involve the initial particle size, hardness and concentration of solid particles, as well as the viscosity and surface tension of continuous phase liquids. These factors are interrelated and need to be optimized through systematic experiments in practice.
Typical application areas
Experimental dispersers are widely used. In the field of chemicals and coatings, it is used for the pre-dispersion of pigments and fillers and the preparation of coating slurries. In nanomaterials research, it is used for the dispersion of nanomaterials such as carbon nanotubes and graphene in the matrix. In food science laboratories, it is used to prepare stable emulsions and sauces. In the field of new energy, it is a key pretreatment equipment for the preparation of lithium-ion battery electrode slurry. In addition, it is also essential in the R&D and quality inspection process of products such as daily chemicals, ceramic pastes, inks and adhesives.
Key points to consider in selection
Choosing the right disperser for your specific experimental needs requires comprehensive consideration. First, the properties of the treated material should be clarified, such as viscosity range, solids content, sensitivity to shear heat, and ultimately the desired dispersion fineness. Secondly, the equipment capacity and functional configuration are determined according to the experimental scale (batch processing volume) and process requirements (whether vacuum defoaming, online monitoring, etc. are required). The technical parameters of the equipment, such as the infinitely variable speed range, motor power, material (e.g. corrosion-resistant 316L stainless steel in contact with the material), and the noise and vibration levels of operation should also be evaluated. Finally, the ease of use, ease of cleaning, and whether it is easy to match subsequent online analysis or sampling are also practical factors to improve experimental efficiency.