Horizontal Pump Low NPSH Stage Integration
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Solution Overview
Problem
Existing horizontal pumping systems face inefficiencies in low net positive suction head (NPSH) applications, requiring separate boost pumps that are costly and space-intensive, and internal NPSH stages complicate design and manufacturing, increasing lead times and costs.
Innovation Solution
A horizontal pumping system with a primary stage assembly and a low NPSH stage assembly, where the low NPSH stage includes a diffuser and impeller designed to operate independently, allowing for a larger diffuser diameter and optimized impeller design to enhance pressure increase under low NPSH conditions, reducing the need for external boost pumps and simplifying design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate boost pump is used to increase NPSHA, then the NPSH requirement is met, but the system becomes expensive and space-intensive
Solution Approach 1:
The patent combines the low NPSH stage and primary stage into a single integrated pump assembly, eliminating the need for a separate boost pump. The low NPSH stage is positioned within the pump housing to receive fluid directly from the suction chamber, merging two previously separate functions into one unified system that reduces complexity and space requirements while maintaining NPSH performance.
2Reliability
If a low NPSH stage is incorporated within the multistage centrifugal pump housing, then the NPSH is boosted, but the design and manufacturing complexity increases
Solution Approach 1:
The pump assembly is segmented into distinct functional stages: a low NPSH stage with a larger diameter diffuser and impeller, and a primary multistage pumping section. This segmentation allows each stage to be optimized independently for its specific function while maintaining a unified integrated structure that simplifies manufacturing compared to fully custom designs.
Solution Approach 2:
The low NPSH stage incorporates a diffuser with a larger diameter than the main pump housing, creating a localized region optimized for low NPSH operation. This local quality change allows the NPSH stage to operate effectively without requiring the entire pump housing to be redesigned, thereby reducing overall manufacturing complexity.
3Reliability
If the diffuser diameter is larger than the pump housing diameter, then the low NPSH stage performance is optimized, but the manufacturing complexity increases
Solution Approach 1:
The low NPSH stage with its larger diameter diffuser is nested within or integrated with the primary pump housing structure. This nesting approach allows the larger diffuser to be accommodated within the overall pump assembly without requiring a completely separate external housing, thereby optimizing performance while controlling manufacturing complexity through integrated design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a cost-effective and space-efficient method to boost NPSH, reducing manufacturing complexities and lead times, while ensuring reliable operation under low NPSH conditions by integrating a modular and standardized low NPSH stage assembly within the pump housing.
Implementation Method 1
a low NPSH impeller contained within the diffuser
Implementation Method 2
a diffuser connected to the pump housing and a low NPSH impeller contained within the diffuser
Data Source
AI summary
A horizontal pumping system has a motor, a suction chamber and a pump driven by the motor. The pump includes a primary stage assembly and a low NPSH stage assembly connected between the primary stage assembly and the suction chamber. The low NPSH stage assembly is external to the primary stage assembly. The low NPSH stage assembly includes a diffuser connected to the pump housing and a low NPSH impeller contained within the diffuser. The diameter of the low NPSH stage assembly is optionally larger than the diameter of the primary stage assembly.