Centrifugal Pump Sealing Ring Self-Centering Design

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Solution Overview

Problem

Centrifugal pumps face challenges in easily assembling and centering sealing rings relative to the impeller without requiring precise component tolerances, leading to increased friction.

Innovation Solution

A centrifugal pump design where the sealing ring rests against the wall surrounding the inlet opening, radially fixed by projections or depressions, allowing for self-centering relative to the impeller and minimizing friction, with a spring element providing axial fixation and tolerance compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sealing ring is fixed within the inlet opening of the wall, then the sealing ring is secured in position, but precise centering relative to the impeller becomes difficult and requires tight tolerances

Engineering Contradiction:
Improvesealing effectivenessVSAvoidcentering precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The fixation function is segmented from the centering function. The sealing ring is divided into areas: one that engages with the inlet opening for securing, and another that rests on the wall surface for centering. This segmentation allows each area to perform its specific function independently without interfering with the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wall surface acts as an intermediary between the sealing ring and the inlet opening. The sealing ring rests on the wall surface (intermediary) to achieve centering, while separately engaging with the inlet opening for fixation. This intermediary enables the decoupling of centering and fixation functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the sealing ring is precisely centered on the wall within the inlet opening, then fixation is achieved, but friction between the sealing ring and impeller increases

Engineering Contradiction:
Improveassembly easeVSAvoidfriction
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

Instead of centering the sealing ring on the inlet opening (conventional approach), the invention inverts the approach by having the sealing ring rest on the wall surface surrounding the inlet opening. This inversion allows the sealing ring to be centered relative to the impeller rather than relative to the inlet opening, thereby reducing friction.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The positional parameter of the sealing ring is changed from being centered on the inlet opening to being positioned on the wall surface surrounding the inlet opening. This parameter change enables the sealing ring to align with the impeller's suction inlet, minimizing relative movement and friction during operation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the sealing ring is allowed to move radially with play, then self-centering relative to the impeller is enabled, but precise positioning relative to the wall is lost

Engineering Contradiction:
Improveself-centering capabilityVSAvoidpositioning precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The sealing ring's radial position is made dynamic rather than fixed. Radial play is intentionally designed to allow the sealing ring to move and self-center relative to the impeller during operation. This dynamic positioning capability enables automatic alignment while maintaining adequate sealing contact.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sealing ring performs self-centering relative to the impeller through its own movement within the radial play. The design enables the sealing ring to automatically align itself with the impeller's suction inlet without requiring external centering mechanisms or precise pre-positioning, achieving self-service centering.

Inventive Principle:
Principle #25Self-service

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

Facilitates easier assembly and centering of the sealing ring, reducing friction and accommodating small positional deviations, while maintaining a sealing contact under varying pressure conditions.

Implementation Method 1

at least one spring element is provided to hold the sealing ring in contact with the wall

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a seal is required at the impeller in the suction inlet area to seal the suction side of the impeller from the discharge side

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2535591B1Centrifugal pump
Publication Date: 2014.04.23 GRUNDFOS MANAGEMENT AS
  • EP2535591B1 patent drawingFigure 1
  • EP2535591B1 patent drawingFigure 2
  • EP2535591B1 patent drawingFigure 3~4

AI summary

The invention relates to a centrifugal pump with at least one impeller (12) and at least one stationary sealing ring (16) which is in sealing contact with the impeller (12), wherein the sealing ring (16) bears against a wall (18) of a housing surrounding the impeller (16), surrounds an inlet opening (20) in the wall (18) and is fixed in a radial direction by at least two projections (22) or recesses formed on the wall (18).