Definition
The Dispersion Mixer is a laboratory equipment that integrates high-speed shearing, mixing and mixing functions. It is widely used in sample preparation and process research in chemical, coating, food, materials science and other fields to achieve uniform dispersion, emulsification or dissolution of solid particles or amorphic liquids through mechanical action.
Principle
The core working principle of the device is based on the high shear forces generated by the rotor-stator structure. The motor drives the rotor to rotate at high speed, drawing the material from the bottom of the container into the working chamber. In the narrow gap, the rotor and stator generate strong mechanical shear, impact and turbulence, so as to quickly break the agglomeration of particles or droplets and achieve uniform dispersion at the microscopic scale. The shear rate can be approximated by the following relations:
γ = (π × D × N) / h
where γ represents the shear rate, D is the diameter of the rotor, N is the rotor speed, and h is the gap width between the rotor and the stator. High rotation speed and reasonable structural design can improve dispersion efficiency.
Measurement and evaluation methods
The evaluation of dispersion effects is usually based on relevant industry standards or research purposes. Common methods include using a laser particle size analyzer to determine the particle size distribution and characterizing the dispersion fineness with D50 or D90 values. The rheological characteristics of the system were monitored by a viscometer. or use a microscope to observe the dispersion and agglomeration of particles. For emulsification systems, the delamination time can be investigated by a stability analyzer. This data provides a quantitative basis for process optimization.
Influencing factors
The dispersion effect is affected by multiple factors. Equipment parameters include rotor speed, dispersion time, rotor stator geometry and clearance size. The process conditions involve material viscosity, solid content, temperature and addition sequence. In addition, the properties of the dispersed medium (e.g., surface tension, polarity) and the properties of the substance to be dispersed (e.g., hardness, hydrophobicity) can also significantly affect the final result. In actual operation, it is necessary to balance each parameter through system testing.
Applications
In the coatings and inks industry, the equipment is used for the pre-dispersion and stabilization of pigment slurries. In the preparation of nanomaterials, the uniform suspension of nanoparticles in the base solution can be realized. It is used in the food industry to prepare stable emulsions if they are emulsions. In the cosmetics field, it completes the homogenization of pastes with its help. In addition, it also plays a key role in the research and development and quality inspection of battery paste, ceramic paste, adhesive and other products.
Key points to consider in selection
When selecting the type, the physical and chemical characteristics of the treated material and the experimental needs should be comprehensively considered. For high-viscosity systems, models with sufficient torque and lifting mechanisms should be selected. If the processing volume is small or cross-contamination needs to be avoided, you can pay attention to models with micro working heads. The speed range should cover applications from low-speed mixing to high-speed shearing. In terms of material compatibility, materials that come into contact with components (e.g., stainless steel, carbide) need to be resistant to material corrosion and wear. In addition, the ease of cleaning, safety protection functions and control accuracy of the equipment are also important reference factors.