Lantern Insert Guide Structure for Centrifugal Pump Alignment

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Solution Overview

Problem

Existing motor-driven centrifugal pumps with a lantern arrangement are prone to unintentional tilting during installation and removal, causing mechanical stress to the impeller due to assembly forces, which can lead to damage, especially when sealing gaps are narrow.

Innovation Solution

The plug-in part is designed with a front cylindrical second guide area featuring an annular seal that rests in a corresponding cylindrical guide within the pump housing, providing a longer seat and ensuring that the plug-in part cannot tilt, thus guiding the impeller straight and minimizing contact with the housing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the insert is installed without additional guiding measures, then the installation process is simple, but the insert tilts unintentionally causing mechanical stress to the impeller

Engineering Contradiction:
Improveinstallation simplicityVSAvoidimpeller protection
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A second guide area with a ring seal is introduced as an intermediary guiding element between the insert and pump housing. This mediator provides additional centering and alignment during insertion, preventing tilting and mechanical stress to the impeller while maintaining installation simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The guiding function is segmented into two distinct areas: a first guide area for initial insertion and a second guide area with ring seal for precise centering and alignment. This segmentation allows each guide area to perform its specific function optimally without complicating the overall installation process

Inventive Principle:
Principle #1Segmentation

2Reliability

If guide pins are used to prevent tilting, then the insert alignment is improved, but the sealing gaps between impeller and pump housing become compromised

Engineering Contradiction:
Improveinsert alignmentVSAvoidsealing gap tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The ring seal in the second guide area serves as an intermediary that provides alignment guidance without physically interfering with the sealing gaps between the impeller and pump housing, unlike rigid guide pins that would compromise these precise tolerances

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ring seal acts as a flexible sealing element that can accommodate minor misalignments during insertion while maintaining the precise sealing gaps required between the impeller and pump housing, avoiding the rigid interference of guide pins

Inventive Principle:
Principle #30Flexible shells and thin films

3Device complexity

If the insert has no sealing element, then the structure is simpler, but mechanical stress during insertion cannot be prevented

Engineering Contradiction:
Improveinsert structureVSAvoidimpeller stress prevention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The ring seal in the second guide area serves as a mediator that provides both sealing function and mechanical guidance during insertion. This dual-function element prevents tilting and stress to the impeller while adding minimal structural complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The ring seal performs multiple functions simultaneously: it provides sealing against the pump housing, guides the insert during insertion to prevent tilting, and protects the impeller from mechanical stress. This multi-functionality reduces the need for separate components

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2447537B1Guide for a lantern insertion part
Publication Date: 2020.06.17 WILO SE
  • EP2447537B1 patent drawingFigure 1
  • EP2447537B1 patent drawingFigure 2

AI summary

The pump has an insertion element (12) coaxially extending into a pump casing (1) and provided with a cylindrical guide portion (20) close to a front end (10) of the pump casing. The guide portion lies in a cylindrical guide (7) of the pump casing. Another cylindrical guide portion (17) is formed with a seal i.e. annular seal (19), at a periphery of the insertion element. The latter guide portion rests in another cylindrical guide (6) of the pump casing. Diameter of the former guide portion is larger than that of the latter guide portion.