Definition
Pneumatic lifting and dispersing machine is a kind of laboratory and industrial equipment that uses compressed air to drive the lifting mechanism and cooperate with a high-speed rotating dispersion disc to mix, disperse, homogenize, dissolve and other treatments of a variety of materials. It is widely used in sample preparation and process research and development in coatings, inks, adhesives, new energy pastes, cosmetics, food and other fields, and is one of the key instruments to achieve efficient dispersion of solid-liquid or liquid-liquid systems.
Principle
The working principle of this equipment is mainly based on the combination of mechanical fluid mechanics and pneumatic control technology. Its core action is divided into two parts: lifting and dispersing. The lifting function is usually realized by a pneumatic cylinder or linear guide rail system, which controls the vertical movement of the dispersion shaft and dispersion disc by adjusting the pressure and direction of the compressed air, so that it can be immersed in or out of the material container, and can be locked at any height. The dispersion function is driven by a high-speed motor, which drives the dispersion disc to rotate at high speed through the drive shaft. The special toothed structure of the dispersion disc creates strong shear, impact and turbulence when rotating, thereby breaking up the agglomerated solid particles and distributing them evenly in the liquid medium. The whole process can usually be precisely set through the control panel for the rotational speed, lifting speed and time.
Measurement and evaluation methods
The measurement and evaluation of the dispersion effect is usually not directly completed by the disperser itself, but indirectly evaluated through subsequent detection methods. Common evaluation dimensions include fineness, viscosity and stability. Fineness is usually measured using scraper fineness meters according to relevant industry standards (e.g., GB/T 1724, ASTM D1210) to assess the degree of fragmentation of particle aggregates. Viscosity is determined using a rotational viscometer (e.g., according to GB/T 10247 or ASTM D2196), and the dispersion process often affects the rheological properties of the system. The stability of the system can be evaluated by standing and observing the stratification, or by using centrifugal sedimentation and laser particle size analyzers. The performance parameters of the disperser itself, such as maximum dispersion viscosity, dispersion capacity, speed range and accuracy, lifting stroke and stability, are key indicators of its capabilities.
Influencing factors
The dispersion effect is affected by multiple factors. In terms of equipment parameters, the diameter, tooth design, material (e.g., stainless steel, carbide) and spindle speed of the dispersion disc are decisive factors, which directly affect the magnitude of the shear force and the shape of the flow field. In terms of process parameters, dispersion time, temperature control, feeding sequence and speed all had significant effects on the results. The material properties are the basic variables, including the hardness, initial particle size, concentration of the dispersed phase, and the viscosity and chemical properties of the continuous phase. In addition, if the shape and size of the container do not match the dispersion disc, there may be insufficient eddy current or splashing, which can affect the dispersion efficiency. The stability of the pneumatic system and the smoothness of the lifting process are also about the repeatability of the operation.
Applications
The application of pneumatic lifting dispersers covers many industrial and R&D fields that require efficient mixing and dispersion. In the coatings and inks industry, it is used for pre-dispersion and pre-grinding of pigments and fillers. In the field of adhesives and sealants, it is used for the homogeneous mixing of resins, additives and fillers. In the field of new energy, it is one of the key equipment for preparing lithium-ion battery electrode paste. In the cosmetics industry, it is used for the homogenization of powders, color pastes and bases. In the food industry, it can be used in the preparation of sauces and condiments. Its pneumatic lifting characteristics are particularly suitable for processes that require frequent vessel changes or dispersion at different heights, providing flexibility and convenience in operation.
Selection considerations
Comprehensive consideration is required when selecting. First, the process requirements should be defined, including the characteristics of the material being processed (e.g., maximum viscosity, corrosiveness, hygienic level), conventional processing volume, and target dispersion fineness. The key performance parameters of the equipment are determined accordingly: appropriate power and torque to accommodate the viscosity of the material, sufficient speed range to provide process flexibility, and appropriate lifting stroke and load capacity to match the vessel size. Compatibility with materials should be taken into account, such as stainless steel or special coatings on contact areas. The pressure and air consumption of the air source need to be matched with the on-site facilities. The degree of automation of the control system (e.g., whether it has program control and data logging functions) affects the reproducibility and efficiency of the process. In addition, safety protection design, noise level, ease of maintenance, and the supplier's technical support and service capabilities are also important reference factors.