Definition
Variable frequency high-speed mixer is a kind of laboratory equipment that adjusts the motor speed through frequency conversion technology to achieve high-speed mixing, dispersion, homogenization or emulsification of materials. It is usually composed of frequency conversion controller, drive motor, stirring shaft and various stirring paddles, and is suitable for sample preparation and process simulation in various industries such as chemical, food, materials, and coatings.
Principle
At the heart of the equipment is the variable frequency drive system. The frequency converter converts the input power frequency power supply into an output power supply with adjustable frequency and voltage, allowing for precise control of the rotational speed of the three-phase asynchronous motor. The relationship can be approximated as:
n = (60f / p) × (1 - s)
where n represents the motor speed, f is the power supply frequency, p is the motor pole log, and s is the difference rate. By increasing the frequency f, the motor speed n is increased, which in turn drives the stirring shaft and the paddle to rotate at high speed. The paddle blade shears, impacts and turbulence on the material during rotation, so as to realize the mixing and dispersion of the material.
Measurement and evaluation methods
The evaluation of agitation often relies on the determination of the physical or chemical properties of the treated sample. Common indirect measurement methods include: using a viscometer to measure the viscosity change of the material after mixing; The laser particle size analyzer was used to detect the particle size distribution and dispersion uniformity of the particle system. The absorbance consistency of the colored solution was measured by a spectrophotometer to evaluate the mixing uniformity. Or the final product is tested for solid content, stability and other standards. The parameters of the mixing process itself, such as actual speed, input power and torque, can be monitored and recorded by the integrated sensors or external velocity meters and power analyzers.
Influencing factors
The stirring effect is affected by multiple factors. In terms of equipment parameters, the geometry, diameter, number of layers of the mixing blade and its installation position in the vessel determine the flow field morphology and shear strength. The spindle speed directly affects the shear rate and input energy. In terms of process parameters, the initial viscosity, solid content, density difference and feeding sequence of the material had a significant effect on the mixing efficiency. Vessel geometry and baffle settings affect fluid circulation and mixing paths. In addition, temperature changes during processing can alter the rheological properties of the material, affecting the final result.
Applications
The equipment plays an important role in several industrial and scientific research fields. In the coatings and inks industry, it is used for the dispersion of pigments and fillers and the homogenization of formulations. In food science, it is used in the emulsification and mixing of food systems such as sauces and dairy products. In the field of nanomaterial preparation, it can be used to disperse precursors and enhance reaction processes. In the adhesives and sealants industry, it is used for uniform mixing of bases and additives. In addition, it is also widely used in the preparation of battery slurry, cosmetics development, and geological sample processing.
Selection considerations
Choosing an adapted inverter high-speed mixer requires a comprehensive evaluation. First of all, the main application purpose should be clarified, such as dispersion or mixing and emulsification, and the type of propeller with corresponding function should be selected accordingly. Secondly, it is necessary to consider the processing range of the sample and the material characteristics, such as viscosity, corrosiveness, and whether it contains particles, etc., to determine the motor power, torque range, and material requirements of the contact parts. The speed range and control accuracy should meet the needs of process development or quality control. Safety features of equipment, such as overload protection, mechanical seal reliability, and explosion-proof design, are critical in specific environments. In addition, the scalability of the equipment, such as the ability to connect vacuum, heating or cooling units, and the completeness of data logging functions, are also considerations for long-term use.