Large fermentation tank mixer- Principle
Due to differences in the shear resistance and required growth environment of various microorganisms, the appropriate stirring speed varies under the same operating conditions and equipment. The appropriate rotational speed needs to be constantly explored during the production process to obtain a reasonable operating speed. In traditional fermentation processes, the stirring system uses multi-layer radial flow agitators. Due to the high shear force of the multi-layer radial flow agitator, the stirring speed is generally set at around 145rpm. After replacing the traditional radial flow stirrer with a combination stirrer, the overall shear strength was greatly reduced. To prevent insufficient shear from causing a low mass transfer coefficient, we increased the original stirring speed by 145mm and set it at 160rpm

Technical points
Ventilation stirring is one of the most energy intensive operations in the fermentation industry. Due to the complexity of the flow inside the mixing tank, people's understanding of it is not deep enough, and traditional radial flow mixers have always been dominant. With the gradual enlargement of fermentation tanks, radial flow agitators are becoming increasingly unsuitable for the requirements of development.
1. The selection of double-layer blades and single-layer blades is based on the geometric dimensions of the container, and the aspect ratio is crucial.
2. The power consumption of a double-layer mixer is not sensitive to changes in ventilation volume, which is determined by the structure of the mixer.
3. The magnitude of shear force is an important factor affecting microbial fermentation, but green berry fermentation is not sensitive to changes in shear force. To improve fermentation efficiency, it is necessary to start from multiple aspects, such as strengthening heat exchange and cleaning dead corners in the fermentation tank. Simply changing the structure of the mixer may not necessarily improve the fermentation unit.
4. The power consumption of axial flow blades is much smaller than that of radial flow agitators. To strengthen the circulation inside the tank, the diameter of the axial flow agitator should be appropriately increased.
5. Accurate calculation of mixing power is difficult, and the power calculation of various mixers has its own particularities. Finding correlation equations that are suitable for different mixer power calculations is of great significance for improving the accuracy of power calculation.
6. Applying computer-aided design to the design of mixing tanks is very effectivebigThe design quality has been improved and the complexity of the design has been reduced. The new combination agitator is the trend in the development of agitation, and overall, it will inevitably replace traditional radial flow agitators. However, there are still many issues that need to be explored in the application of combination mixers. If the flow inside the mixing tank can be analyzed from the perspective of computational fluid dynamics, it will provide a deeper understanding of the essential laws inside the mixing tank.

Large fermentation tank mixer- Blender design
model
impeller diameter
Shaft length
Shaft Diameter
Discharge volume
stay time
agitation intensity
Mixing time and uniformity
rotational speed
mixing efficiency
Discharge direction
Motor Power
motor speed
Motor Efficiency
Motor installation bending moment
Motor torque
The distance from the dosing tube to the center of the impeller
Gearbox gear oil grade
CFD model diagram