Definition
The heated stirring disperser is a general laboratory equipment that integrates heating, mechanical stirring and high shear dispersion functions. It uses a rotating agitator or dispersion disc to force mixing, refinement and homogenization between liquid medium and solid particles or a variety of asynchronous solutions under controlled temperature conditions, aiming to prepare a uniform and stable dispersion system.
Principle
The core working principle of the equipment is based on the synergy of mechanical force and thermal energy. The motor drives the spindle to rotate at high speed, driving the stirring paddle or toothed dispersion disc at the end to move. The high linear velocity at the edge of the dispersion disc creates a strong shear force, overcoming the cohesion between the particles, breaking them up and dispersing them in a continuous phase. At the same time, the heating module (usually an electric heating plate) or jacket integrated into the bottom of the vessel provides precise temperature control and maintenance of the material to reduce system viscosity or facilitate certain physicochemical processes, thereby improving dispersion efficiency and final product stability.
Measurement and evaluation methods
Dispersion effects are evaluated using a range of physical measurement methods. Particle size distribution is a core metric that can be measured by a laser particle size analyzer, and its principle is based on the scattering characteristics of particles on the laser. Dispersion stability can be assessed by standing by observing the stratification time or by monitoring changes in backscattered light flux using multiple light scatterometry. System uniformity can be judged by sampling to determine the consistency of solids or viscosity at different locations. For specific systems, microscopic observation (such as light microscopy or electron microscopy) can also be used to visually assess the dispersion and agglomeration of particles.
Influencing factors
The dispersion effect is affected by multiple factors. In terms of equipment parameters, the type, diameter, linear speed and distance from the bottom of the dispersion disk are the key, and the calculation formula of linear velocity v is: v = π × d × n, where d is the diameter of the dispersion disk and n is the rotational speed. Process parameters include dispersion time, temperature control range, and accuracy. The material properties cover the viscosity and density of the continuous phase, as well as the particle size, hardness, concentration and surface properties of the dispersed phase. In addition, the order and method of feeding will also have an impact on the initial agglomeration state.
Main application areas:
The equipment is widely used in sample preparation and pretreatment in many industrial and scientific research fields. In the coatings and inks industry, it is used for pre-dispersion and pre-grinding of pigments and fillers. In the field of nanomaterials, it is used for the deagglomeration and stable dispersion of nanopowders such as carbon nanotubes and graphene in base liquids. In food science, it is used to prepare emulsified sauces, stabilizing emulsions, etc. In the research and development of battery materials, it is used for the mixing and homogenization of electrode slurry. In addition, it also plays an important role in the fields of chemicals, cosmetics, ceramic pastes, etc.
Key points to consider in selection
Selection is based on specific application requirements. First, it is necessary to clarify the properties of the treated material, such as viscosity range, corrosiveness, volatility and sensitivity to shear forces, to determine the material requirements (such as stainless steel, special alloys) and sealing methods. Choose the right working capacity and motor power according to the scale of the experiment (from milliliters to upgrades). Temperature control requirements, including maximum heating temperature, temperature control accuracy, and whether cooling functions are required, are the basis for choosing the type of heating module. The equipment should have stepless speed regulation and the speed range should cover the needs from low-speed mixing to high-speed dispersion. In terms of safety, attention should be paid to overheating protection, overload protection and necessary explosion-proof design. In addition, the easy-to-clean design, good user interface, and support for process data logging also have an impact on the repeatability and efficiency of experiments.