Definition
The automatic disperser is a laboratory and industrial equipment used to achieve efficient mixing, dispersion and homogenization of materials. It automatically completes the dispersion process through the combination of mechanical and automatic control systems, and is widely used in the field of sample preparation and process research in various industries such as coatings, inks, nanomaterials, food, and cosmetics. Its core function is to evenly disperse solid particles in liquid medium under specific conditions, and destroy particle agglomeration to form a stable dispersion system.
Principle
The fully automatic disperser works on the principle of high-speed shearing. The equipment usually consists of a drive motor, a dispersion shaft, a dispersion disc (or rotor-stator structure) and an automated control system. The motor drives the dispersion shaft to rotate at high speed, driving the dispersion disc to move in the sample container. The high linear velocity of the edge of the dispersion disc creates a strong shear force that acts on the material. At the same time, the fluid forms strong turbulence and circulation in the vessel, causing the particle clusters to be torn into smaller units and evenly distributed into the liquid phase. The automation system can preset and adjust parameters such as rotational speed, time, and temperature to achieve repeatability and precise control of the process.
The shear stress τ is closely related to the dispersion effect, and its basic relationship can be expressed as: τ = μ · γ, where μ is the hydrodynamic viscosity and γ is the shear rate. A higher shear rate contributes to improved dispersion efficiency.
Measurement and evaluation methods
The evaluation of dispersion effect should be combined with process parameters and final product indicators. Process monitoring typically includes real-time measurements of speed, torque, temperature, and energy consumption. After the dispersion is completed, the particle size distribution and D50 value can be measured by laser particle size analyzer to evaluate the dispersion fineness. The rheological properties of the system were measured using a viscometer; The morphology and agglomeration state of the particles were observed by microscope. or through settlement experiments, gloss, color measurement, etc., the dispersion stability and product performance are evaluated according to specific industry standards.
Influencing factors
The dispersion effect is affected by multiple factors. Equipment parameters include the shape, diameter, linear velocity, and vessel geometry, which determine the flow field and shear strength. Process parameters such as dispersion time, rotational speed, temperature control and feeding sequence have a direct impact on dispersion efficiency and final product stability. In terms of material characteristics, the hardness, initial particle size, surface properties of the particles, the viscosity, polarity, and the type of additives of the medium will all change the difficulty of dispersion and the required energy input. Operational factors such as the immersion depth and eccentric position of the dispersion disc can also affect the flow field uniformity.
Applications
Automatic dispersers play an important role in many industrial and scientific research fields. In the coatings and inks industry, it is used to disperse pigments in resins, which affects the coloring and gloss of products. In the preparation of nanomaterials, it is used for the deagglomeration and uniform distribution of nanoparticles in the matrix. In the food industry, it is used for the homogenization of sauces, dairy products and other systems. In the cosmetics sector, it is used for the dispersion of powders in creams. In addition, it is also a key equipment in R&D and quality control in emerging technologies such as battery paste, ceramic paste, and polymer composite materials.
Selection considerations
When choosing a fully automatic disperser, a systematic evaluation is required. First, the process requirements are clarified, including the viscosity range of the material being processed, the expected particle size target, the processing batch and the required capacity. Depending on this, the type of equipment is selected, such as a high-speed disperser or a rotor-stator homogenizer with a higher shear force. The equipment specifications need to consider whether the motor power, speed range, and torque output can meet the material dispersion resistance. In terms of automation functions, attention should be paid to whether it is necessary to program and control multi-stage processes, data logging, and joint control with external sensors. Material compatibility requires ensuring that the contact component material can resist material chemical corrosion. Safety features such as overload protection and emergency braking should also be taken into account. Finally, refer to relevant international standards (such as safety and testing standards related to mixing equipment) and general industry specifications to ensure the applicability of the equipment.