What Is A Mixed Flow Submersible Pump?

A mixed flow submersible pump is a specialized type of pump designed to operate while fully submerged in the fluid it's pumping. This pump combines the characteristics of both axial flow and radial flow pumps, offering a unique solution for various applications that require efficient handling of large volumes of liquid at moderate pressures. Understanding the nature and design of these pumps is crucial for engineers and operators working in industries such as water treatment, irrigation, and flood control.

Combines features of axial flow pump and radial flow pump

The defining feature of a mixed flow submersible pump is its ability to merge the advantages of axial and radial flow pumps. In an axial flow pump, the fluid moves parallel to the pump shaft, which is ideal for moving large volumes of liquid with relatively low head pressure. Radial flow pumps, on the other hand, discharge fluid perpendicular to the shaft and are better suited for creating higher pressures with lower flow rates.

By combining these two flow patterns, mixed flow submersible pumps achieve a balance that allows for both high flow rates and moderate pressure heads. The impeller design in these pumps is crucial to achieving this balance. Typically, the impeller blades are curved and angled in a way that directs the fluid both axially and radially as it moves through the pump. This unique design allows the pump to handle a wide range of flow conditions more efficiently than either a pure axial or radial flow pump could on its own.

The submersible aspect of these pumps adds another layer of functionality. Being designed to operate while completely submerged, these pumps eliminate the need for priming and reduce the risk of cavitation, which is a common issue in surface-mounted pumps. This characteristic makes them particularly suitable for applications such as deep well pumping, sewage handling, and flood control, where the pump needs to be close to or within the fluid source.

Mixed flow submersible pump designing

Designing a mixed flow submersible pump requires careful consideration of several key factors to ensure optimal performance and longevity. Three critical aspects stand out in the design process: impeller speed, multi-stage design, and pre-swirl control.

Impeller speed is a crucial consideration in pump design. For mixed flow submersible pumps, the circumferential speed of the impeller is typically limited to 25 to 30 m/s. This limitation is primarily to prevent cavitation, a phenomenon where vapor bubbles form and collapse within the pump, potentially causing damage and reducing efficiency. By controlling the impeller speed, designers can maintain a balance between pumping capacity and the risk of cavitation, ensuring reliable operation across various conditions.

In applications requiring a head of more than 60 meters, a multi-stage pump design may be necessary. Multi-stage pumps use several impellers in series, each adding to the total head pressure. This design allows mixed flow submersible pumps to achieve higher pressures while maintaining their advantageous flow characteristics. The multi-stage approach is particularly useful in deep well applications or scenarios where fluids need to be lifted to significant heights.

Pre-swirl control is another important consideration in mixed flow submersible pump design. Unlike some other pump types, the impeller geometry of mixed flow pumps does not allow for closed-loop control through impeller blade angle adjustment. As a result, pre-swirl control is often recommended. This technique involves manipulating the fluid flow before it enters the impeller, typically through the use of inlet guide vanes or other flow-directing structures. Pre-swirl control can help optimize pump performance across a range of operating conditions, improving efficiency and reducing energy consumption.

Economic Advantages

One of the key components that contribute to the efficiency and economic advantages of mixed flow submersible pumps is the axial-radial guide vanes. These guide vanes play a crucial role in directing the flow of fluid through the pump, optimizing the conversion of mechanical energy into fluid energy.

The economic advantages of axial-radial guide vanes in mixed flow submersible pump stem from several factors. Firstly, they help to stabilize the flow pattern within the pump, reducing turbulence and energy losses. This increased efficiency translates directly into lower power consumption, reducing operating costs over the pump's lifetime.

Additionally, the guide vanes contribute to the pump's ability to handle a wider range of flow conditions efficiently. This versatility can be particularly valuable in applications where flow rates may vary significantly, as it allows the pump to maintain good efficiency across its operating range. The result is a more adaptable pumping solution that can reduce the need for multiple pump types or frequent replacements, leading to cost savings in both equipment and maintenance.

The design of axial-radial guide vanes also tends to result in a more compact pump assembly compared to other designs with similar capacities. This compact nature can lead to savings in installation costs and space requirements, which can be significant in large-scale projects or installations with space constraints.

Submersible mixed flow pump factories

When it comes to selecting a manufacturer for submersible mixed flow pumps, Tianjin Kairun offers a range of models designed to meet various application needs. Their product line includes the 350QZ-50, 500QZ-75, 600QZ-100, 700QZ-100, and 800QZ-5 models, among others. These pumps are engineered to leverage the advantages of mixed flow design while addressing the key design considerations discussed earlier.

Tianjin Kairun's submersible mixed flow pumps are likely designed to provide efficient performance across a range of flow rates and pressures, making them suitable for applications such as flood control, irrigation, and wastewater management. The submersible design adds the benefit of eliminating priming issues and allowing for installation in flooded or underwater environments.

For those considering submersible mixed flow pumps for their applications, it's advisable to contact Tianjin Kairun directly at catherine@kairunpump.com. Direct communication with the manufacturer allows for a detailed discussion of specific project requirements, ensuring the selection of the most appropriate pump model for the intended application.

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Tuzson, J. (2000). Centrifugal Pump Design. John Wiley & Sons.

Hydraulic Institute. (2010). Rotodynamic Pumps for Pump Intake Design. Hydraulic Institute.