Definition
Electric variable frequency disperser is a kind of laboratory and industrial equipment used to achieve efficient mixing, dispersion and homogenization of materials. It drives the dispersion head to rotate at high speed in the medium through a motor, generating strong shear, impact and turbulence, so as to evenly disperse solid particles in the liquid or form a stable system for different mutual solutions. The core feature of this equipment is that its drive motor adopts frequency conversion speed regulation technology, allowing the operator to precisely adjust the rotational speed over a wide range to adapt to the process requirements of different viscosities and different dispersion stages.
Principle
The working principle of the electric variable frequency disperser is based on the shear and turbulence effects in fluid dynamics. When the motor receives a specific frequency of current controlled by the frequency converter, it drives the spindle to rotate at a set speed. The dispersion head mounted at the end of the spindle (usually a serrated or disc rotor) rotates at high speed. When the dispersion head rotates, the toothed structure on its edge exerts a strong mechanical force on the surrounding fluid, producing the following effects: First, the high-speed rotating blades suck the material from the bottom of the container and throw it axially to the container wall, forming a circulating flow; Secondly, under the extremely high velocity gradient between the edge of the dispersion head and the fluid, strong shear stress is generated, which can effectively break the agglomeration between particles. Finally, the resulting microscale turbulent vortex further promotes the mixing and dispersion between components. The whole process can be roughly described by a simplified shear rate formula: γ = (π * D * N) / 60h, where γ represents the shear rate, D is the diameter of the dispersion head, N is the rotational speed, and h is the characteristic gap between the dispersion head and the wall of the container. The variable frequency control allows the rotational speed N to be adjusted precisely and linearly, allowing for direct control of the shearing process.
Measurement and evaluation methods
The measurement and evaluation of dispersion effect usually revolves around system uniformity and particle size. A common method is to conduct particle size analysis after sampling, using a laser particle size analyzer to determine the particle size distribution, and using characteristic particle size parameters such as D50 and D90 as quantitative indicators of dispersion. For slurry systems, the viscosity can be measured with shear rate, and the dispersion stability can be evaluated by rheological curves. Visual observation and scraper fineness meter testing are also ways to quickly determine the presence of large particles. Under laboratory conditions, the effect of dispersion process parameters can be systematically evaluated by comparing the particle size data of samples at different rotation speeds and dispersion times. These measurements refer to relevant industry standards, such as dispersion fineness test methods that may be referenced in the coatings sector.
Influencing factors
The dispersion effect is affected by multiple factors. In terms of equipment parameters, the geometry and diameter of the dispersion head directly affect the flow field structure and shear strength. The rotational speed determines the amount of input energy, which needs to be matched with the viscosity of the material. In the process parameters, dispersion time is the key variable, insufficient may lead to incomplete dispersion, and too long may cause temperature rise or excessive fragmentation. The order and method of feeding materials will also affect the initial agglomeration state. The material properties themselves, such as the hardness, initial particle size, and concentration of solid particles, as well as the viscosity and surface tension of the liquid medium, are all intrinsic factors that determine the required dispersion energy and final effect. In addition, the shape and size of the vessel, as well as the immersion depth and relative position of the dispersion head in the vessel, affect the circulation pattern of the fluid, which has an effect on macro mixing efficiency.
Applications
Electric inverter dispersers have a wide range of uses in many industrial and scientific research fields. In the coatings and inks industry, it is used to evenly disperse pigments and fillers in resin bases to ensure stable product color and performance. In nanomaterial preparation, it can be used for the primary dispersion of nanoparticles in solution. In the field of battery slurry preparation, it is essential for the uniform mixing of electrode active substances, conductive agents, and binders. In addition, the equipment plays a role in the emulsification of sauces in the food industry, the preparation of pastes in the cosmetics industry, and the preparation of catalyst suspensions in the chemical industry. Its value lies in providing a precisely controlled and easily scaled up tool for laboratory test formulation development and process parameter exploration.
Selection considerations
Choosing the right electric inverter disperser requires comprehensive consideration. First of all, the properties of the treated material should be clarified, such as the expected processing volume, viscosity range, whether it is corrosive or abrasive, which is related to the choice of equipment material, motor power and mechanical structure strength. Secondly, determine the appropriate dispersion head type and size based on the shear strength and mixing required for the process target. The control accuracy, speed range and speed regulation stability of the frequency converter are the key to ensuring process repeatability. Safety features of equipment, such as overload protection, reliability of mechanical seals, also need to be evaluated. For R&D use, it may be necessary to consider whether the device is easy to clean and has an expansion interface to connect to other measurement probes. The final choice should be based on specific application requirements, balancing performance parameters, ease of use, and cost.