Detachable Crossover Pipes in Multistage Pumps for Lower Hydraulic Loss

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Solution Overview

Problem

Conventional multistage pumps face challenges with cleaning requirements for crossover passageways due to their length and small cross-sectional areas, leading to increased costs and potential performance issues.

Innovation Solution

A multistage pump design featuring detachable crossover and crossunder pipes with improved internal surface roughness, allowing for smaller cross-sections and reduced hydraulic losses, and enabling more flexible positioning and hydraulic optimization through Computational Fluid Dynamics (CFD).

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional integrated crossover passageways are used in multistage pumps, then the pump structure is simplified, but the passageways require special cleaning processes due to their length and small cross-sectional areas, increasing manufacturing cost and time

Engineering Contradiction:
Improvepump structureVSAvoidcleaning process requirements
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The invention divides the crossover passageway into two separate components: a stationary passageway integrally formed with the pump casing, and a detachable pipe assembly that can be removed independently. This segmentation allows the pipe assembly to be cleaned or replaced without cleaning the entire integrated passageway, eliminating the need for special cleaning processes while maintaining structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extracts the crossover pipe function from the integrated casing structure, creating a separate detachable pipe assembly. This extracted component can be easily removed and cleaned independently, solving the cleaning difficulty problem while preserving the benefits of an integrated design.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If conventional integrated crossover passageways with rectangular or trapezoidal cross-sections are used, then manufacturing is straightforward, but hydraulic losses increase due to surface roughness and undulations

Engineering Contradiction:
Improvepassageway formationVSAvoidhydraulic losses
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The invention changes the cross-sectional geometry parameter of the passageway from rectangular or trapezoidal to circular. This parameter change reduces hydraulic losses because circular cross-sections have smaller wetted perimeters for the same flow area, reducing friction losses. The circular cross-section is achieved by using a standard pipe with a circular profile rather than casting a rectangular or trapezoidal passage.

Inventive Principle:
Principle #35Parameter changes

3Ease of repair

If detachable crossover and crossunder pipes are used, then cleaning and maintenance are simplified, but the device complexity increases

Engineering Contradiction:
Improvecleaning and maintenanceVSAvoidnumber of components
Core Design Contradiction:
Ease of repairVSDevice complexity

Solution Approach 1:

The invention merges the detachable pipe assembly with the pump casing through a standardized connection interface that integrates the pipe mounting blocks into the casing structure. This merging approach allows the pipes to be detachable for maintenance while maintaining a unified, compact overall structure that does not significantly increase device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3828418B1Multistage pump
Publication Date: 2025.12.31 SULZER MANAGEMENT AG
  • EP3828418B1 patent drawingFigure 1~2
  • EP3828418B1 patent drawingFigure 3~4
  • EP3828418B1 patent drawingFigure 5~6

AI summary

A multistage pump includes a pump casing, a shaft, a first impeller, a second impeller, and a pipe. The shaft is rotatably disposed within the pump casing and has a longitudinal axis. The first impeller is disposed within the casing at a first position along the shaft. The second impeller is disposed within the casing at a second position and along the shaft. The pipe is detachably attached to the pump casing, and has an inlet and an outlet, the inlet disposed at the discharge of the first impeller and the outlet disposed at an eye of the second impeller, such that discharge from the first impeller can be conveyed to the eye of the second impeller.