What Is The Working Principle Of Electric Submersible Mixer?

Electric submersible mixer is an essential tool in various industries, including wastewater treatment, chemical processing, and food production. These devices are designed to operate while fully submerged in liquids, providing efficient mixing and homogenization of fluids.

Motor and Impeller

At the heart of every electric submersible mixer lies the motor and impeller assembly. The motor is typically an electric induction motor, specially designed to operate in submerged conditions. These motors are sealed to prevent water ingress and are often filled with oil for cooling and lubrication. The motor's housing is usually made of corrosion-resistant materials such as stainless steel or cast iron with protective coatings to withstand the harsh environments they often operate in.

The motor is directly coupled to the impeller, which is the primary component responsible for generating the mixing action. Impellers come in various designs, each optimized for specific mixing requirements. Common impeller types include axial flow propellers, radial flow turbines, and hydrofoil designs. The choice of impeller depends on factors such as the viscosity of the fluid, the desired flow pattern, and the mixing intensity required.

Axial flow propellers are often used in applications where large volumes of fluid need to be circulated with relatively low shear. These impellers create a flow parallel to the shaft and are efficient at moving fluid over long distances. Radial flow turbines, on the other hand, generate flow perpendicular to the shaft and are useful for applications requiring high shear and turbulence. Hydrofoil impellers combine aspects of both axial and radial flow, offering a balance between pumping capacity and shear.

The motor and impeller assembly is typically mounted on a support structure that allows for adjustable positioning within the tank or basin. This flexibility enables operators to optimize the mixer's position for maximum efficiency and uniform mixing throughout the fluid volume.

Impeller Rotation

The working principle of an electric submersible mixer revolves around the rotation of the impeller. When electrical power is supplied to the motor, it converts electrical energy into mechanical energy, causing the motor shaft to rotate. This rotational motion is directly transferred to the impeller, which spins at high speeds, typically ranging from 700 to 1800 RPM, depending on the specific design and application.

As the impeller rotates, it interacts with the surrounding fluid, creating complex flow patterns. The rotation generates both primary and secondary flows within the liquid. The primary flow is the main circulation pattern induced by the impeller, while secondary flows are smaller-scale eddies and vortices that contribute to local mixing and turbulence.

The speed of impeller rotation plays a crucial role in determining the mixing intensity and energy input into the system. Higher rotational speeds generally result in increased turbulence and more vigorous mixing. However, the optimal speed depends on various factors, including fluid properties, tank geometry, and the specific mixing objectives.

Many modern electric submersible mixers are equipped with variable frequency drives (VFDs) that allow for precise control of the impeller speed. This feature enables operators to adjust the mixing intensity to match changing process requirements or to optimize energy consumption.

Circulation and Mixing

The primary function of an electric submersible mixer is to create circulation and mixing within the fluid. As the impeller rotates, it imparts kinetic energy to the surrounding liquid, setting it in motion. This motion creates a flow pattern that extends throughout the tank or basin, promoting overall circulation and homogenization of the fluid.

The specific flow pattern generated by the mixer depends on several factors, including the impeller design, mixer positioning, and tank geometry. In a typical setup, the impeller creates a primary flow stream that moves away from the mixer. This stream then interacts with the tank walls and other boundaries, creating recirculation patterns that help distribute the mixing effect throughout the entire volume.

The circulation induced by the mixer serves several purposes. It helps maintain solids in suspension, preventing settling and the formation of dead zones within the tank. In wastewater treatment applications, this is crucial for keeping organic matter and microorganisms well-mixed and exposed to oxygen. In chemical processing, circulation ensures uniform distribution of reactants and helps maintain consistent product quality.

The mixing action also promotes heat transfer and mass transfer within the fluid. This is particularly important in applications involving chemical reactions, where uniform temperature distribution and efficient mixing of reagents are essential for optimal process performance.

Thrust Generation

An often-overlooked aspect of electric submersible mixer operation is thrust generation. As the impeller rotates and moves fluid, it creates a reactive force known as thrust. This thrust is essentially the reaction to the momentum imparted to the fluid by the impeller.

The direction and magnitude of the thrust depend on the impeller design and orientation. Axial flow impellers typically generate thrust in the direction of the shaft, while radial flow impellers produce thrust perpendicular to the shaft. The thrust generated by the mixer can be substantial, especially in larger units, and must be considered in the design of the mixer support structure and mounting arrangements.

In some applications, the thrust generated by the mixer is deliberately used to create specific flow patterns or to influence the overall fluid dynamics within the tank. For example, in circular tanks, the mixer might be positioned at an angle to create a swirling motion that enhances mixing and prevents the formation of dead zones.

Electric submersible mixer manufacturers

When selecting an electric submersible mixer for your specific application, it's crucial to choose a reputable manufacturer that can provide high-quality, reliable products tailored to your needs. Tianjin Kairun is a notable manufacturer in this field, offering a range of electric submersible mixers suitable for various industrial applications.

Recognizing that each application may have unique requirements, Tianjin Kairun offers customization services to meet specific needs. Their team of experienced engineers can design and manufacture custom submersible mixers tailored to particular applications. This customization capability ensures that users can obtain a mixer that precisely fits their operational parameters, whether it's for large-scale wastewater treatment, chemical processing, or specialized industrial mixing applications.

If you're in the process of selecting an electric submersible mixer manufacturer and would like to explore customized solutions that align with the working principles discussed in this article, Tianjin Kairun welcomes your inquiries. For more information about their products, customization options, and technical support, you can contact them at catherine@kairunpump.com.

References

1. Harnby, N., Edwards, M. F., & Nienow, A. W. (2001). Mixing in the Process Industries. Butterworth-Heinemann.

2. Paul, E. L., Atiemo-Obeng, V. A., & Kresta, S. M. (2004). Handbook of Industrial Mixing: Science and Practice. Wiley-Interscience.

3. Uhl, V. W., & Gray, J. B. (1986). Mixing: Theory and Practice. Academic Press.

4. Zlokarnik, M. (2001). Stirring: Theory and Practice. Wiley-VCH.5. Oldshue, J. Y. (1983). Fluid Mixing Technology. McGraw-Hill.

5. Tatterson, G. B. (1991). Fluid Mixing and Gas Dispersion in Agitated Tanks. McGraw-Hill.