A liquid dynamic mixer is a device that relies on the rotation or reciprocating motion of mechanical power components (such as rotors, gears, etc.) to force the fluid to generate intense turbulence and shear force, thereby achieving rapid and uniform mixing of two or more high-viscosity liquid materials within an extremely short tube pass. The core principle is to perform pulsed shearing and kneading on the fluid through the relative motion between the moving and stationary particles (or gears), breaking through the limitation of static mixers that rely on the fluid’s own energy, and significantly improving the mixing efficiency and applicability.
I. Core Advantage: The unique value of dynamic mixers
Efficient mixing and shortened pipe pass
Dynamic mixers achieve thorough mixing by directly applying mechanical power to the fluid within an extremely short tube pass (typically less than 1/10 of that of static mixers). For instance, the planetary gear type dynamic mixer, through the revolution and rotation of the central gear and the planetary gear, causes the polymer melt to undergo multiple shears in the slit, and its mixing efficiency is much higher than that of the multi-stage baffle design of the static mixer.
Low pressure drop, suitable for high-viscosity materials
Static mixers, due to their long tube pass and complex baffle structure, are prone to high pressure drop (especially for high-viscosity materials), while dynamic mixers have short tube passes and smooth flow channels, resulting in extremely low pressure drop. For instance, in the processing of degradable materials such as PLA, dynamic mixers can prevent the materials from degrading due to prolonged residence, while reducing the pressure requirements for gear pumps (from over 20MPa needed for static mixers to below 10MPa for dynamic mixers).
The design without blind spots prevents material accumulation
The rotor and stator clearance of the dynamic mixer is adjustable, and the flow channel is smooth without any deflection, completely eliminating the dead corner problem inside the static mixer. This is particularly important in fields with extremely high hygiene requirements such as food and medicine, as it can prevent cross-contamination and material deterioration.
Adapt to special working conditions and expand the application scope
Degradable materials: Dynamic mixers are suitable for processing easily degradable materials such as polylactic acid (PLA) and polycaprolactone (PCL), avoiding molecular chain breakage caused by high pressure drop and long residence time in static mixers.
High-viscosity fluids: such as silicone oil, resin, etc. Dynamic mixers can achieve uniform dispersion through strong shear force, while static mixers may cause uneven mixing due to insufficient flow rate.
In the field of microfluidics: Dynamic micro-mixers (such as electro-hydraulic power pumps and ultrasonic vibration mixers) achieve rapid mixing of nanoscale liquids by inducing fluid convection through electric fields or ultrasonic waves, and are suitable for scenarios such as biochips and drug screening.
Ii. Technical Classification: Diversified Structures of Dynamic Mixers
Planetary gear type dynamic mixer
Structure: The central gear is connected to the screw, and the planetary gears are evenly distributed around it, meshing with the gears inside the barrel.
Principle: The rotation of the screw drives the central gear, and the planetary gears revolve around and rotate on their own axes, causing the melt to undergo multiple shears in the gear slits.
Application: Polymer modification, blending extrusion (such as PP/ elastomer blending).
Features: High uniformity of mixing, but large radial dimensions and complex manufacturing.
Dynamic and static gear ring type dynamic mixer
Structure: The rotor’s moving gear ring and the barrel’s stationary gear ring are combined, with multiple sets of gear rings arranged axially.
Principle: When the fluid passes through the gap of the gear ring, it is subjected to pulsed shearing, and each group of gear rings enhances the mixing once.
Application: Dispersion and homogenization of high-viscosity fluids (such as silicone oil).
Features: Strong shearing force, but the gear ring is worn and needs to be replaced regularly.
Microfluidic dynamic mixer
Structure: Silicon-based microchannels, piezoelectric ceramic vibrating membranes, parallel electrodes.
Principle
Electro-hydraulic power pump: A direct current voltage is applied to the electrodes to induce the movement of surface charges, generating shear force to mix the fluid.
Ultrasonic vibration mixer: Piezoelectric ceramic vibration membranes excite ultrasonic waves to generate convection in the fluid.
Application: Mixing of biological samples, preparation of drug microspheres.
Features: Small mixing volume (nanoscale upgrade), fast response, but has requirements for fluid conductivity.
Iii. Application Scenarios: Industry Coverage of dynamic mixers
Polymer materials industry
In the chemical fiber industry, the dynamic mixer in the original liquid coloring can achieve uniform dispersion of pigments and polyester, avoiding color differences.
In the plastic industry, in multiphase blending (such as PP/ glass fiber), dynamic mixers can increase the dispersion efficiency by more than 50% compared to static mixers.
Food and Medicine
Food: Dynamic mixers are used for homogenizing jams and chocolate sauces to prevent bacterial growth caused by dead corners in static mixers.
In the pharmaceutical industry, in vaccine production, dynamic mixers can achieve rapid mixing of antigens and adjuvants, shortening the production cycle.
Environmental Protection and Energy
Wastewater treatment: Dynamic mixers are used for the mixing of sludge and flocculants to enhance sedimentation efficiency.
In the preparation of electrode slurry for lithium batteries, dynamic mixers can achieve uniform dispersion of active substances and conductive agents, enhancing battery performance.
Iv. Selection Guide: How to Choose the Right Dynamic Mixer
Material properties
Viscosity: For high-viscosity materials (such as silicone oil), the dynamic and static gear ring type or planetary gear type is preferred. For low-viscosity materials (such as water-based coatings), a microfluidic mixer can be selected.
Heat-sensitive: For degradable materials, a dynamic mixer with a short tube pass and low pressure drop should be selected to avoid degradation.
Process requirements
Mixing efficiency: In scenarios where high uniformity of mixing is required (such as pharmaceutical intermediates), choose planetary gear type or multi-stage dynamic and static gear ring type.
Pressure limit: When the pressure resistance capacity of downstream equipment (such as filters) is low, dynamic mixers should be given priority.
Production scale
Laboratory grade: Microfluidic dynamic mixer (mixing volume 260-1700μL), suitable for small-batch research and development.
Industrial grade: Planetary gear type or dynamic and static gear ring type (flow rate up to several hundred kg/h), suitable for continuous production.
V. Future Trends: Innovative Directions of Dynamic Mixers
Intelligent control: Integrating sensors and AI algorithms, it can adjust parameters such as rotor speed and gear ring clearance in real time to achieve adaptive mixing.
Miniaturization and integration: Develop micro-nano dynamic mixers, integrate them with microfluidic chips and 3D printing equipment, and expand applications in fields such as biomedicine and materials science.
Green manufacturing: Utilizing degradable materials to manufacture mixer components reduces the environmental impact throughout the equipment’s life cycle.