Stator Compression Device Using Elastic Locking Ring

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Solution Overview

Problem

Existing compression methods for stator units in multi-stage centrifugal pumps, such as those using tubular elements with limited surface area or elastic locking rings with reduced elasticity, fail to maintain effective compression beyond a certain pressure limit, leading to leakage and potential pump damage.

Innovation Solution

A compression device utilizing a thinner, more elastic locking ring with a counteracting element and thrust unit that distributes compression force uniformly, allowing for higher pressure handling without deformation, and eliminating the need for openings in the tubular case.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a tubular element with holed flange is used to compress the stator unit, then the compression force is applied to the stator unit, but the lateral openings collapse under high compression force causing loss of compression and leakage

Engineering Contradiction:
Improvecompression forceVSAvoidtightness
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The compression device is segmented into distinct functional components: a thrust unit for applying compression force, a locking ring with constrained movement for force transmission, and a counteracting element for stabilizing the locking ring. This segmentation allows each component to perform its specific function optimally without interfering with others, resolving the contradiction between applying sufficient compression force and maintaining structural reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking ring acts as an intermediary element between the thrust unit and the stator unit. It receives the compression force from the thrust unit and transmits it to the stator unit while its constrained movement prevents direct contact that would cause the lateral openings to collapse. This intermediary mechanism enables force transmission while maintaining the integrity of the tubular case openings.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stress or pressure

If an elastic locking ring is used to support compression force, then the compression stress is distributed uniformly on the tubular case, but the locking ring deforms axially under high compression force causing it to come off the seat

Engineering Contradiction:
Improvecompression stress distributionVSAvoidlocking ring position
Core Design Contradiction:
Stress or pressureVSStability of the object's composition

Solution Approach 1:

The locking ring is designed with non-uniform cross-sectional thickness, being thicker at certain locations and thinner at others. This local variation in quality allows the ring to have different mechanical properties at different locations - providing sufficient elasticity for stress distribution while maintaining adequate structural strength and axial stability under high compression forces to prevent the ring from coming off the seat.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The locking ring combines materials or structural configurations that exhibit both elastic behavior for stress distribution and sufficient rigidity for positional stability. The composite design enables the ring to deform elastically under compression for uniform stress distribution while maintaining enough structural integrity to remain seated on the tubular case under high compression forces.

Inventive Principle:
Principle #40Composite materials

3Force

If the thickness of the elastic locking ring is increased to bear higher compression force, then the compression force capacity increases, but the usable resting surface is reduced limiting the applicable compression force

Engineering Contradiction:
Improvecompression force capacityVSAvoidusable resting surface
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

The locking ring features non-uniform thickness distribution, with thicker sections providing structural strength for bearing compression forces and thinner sections maintaining a larger usable resting surface area. This local quality variation resolves the contradiction by allowing the ring to support higher compression forces while preserving adequate contact surface with the tubular case for force distribution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The solution moves from a uniform two-dimensional thickness parameter to a three-dimensional variable thickness profile. By varying the thickness in the radial dimension while maintaining the axial and circumferential dimensions, the design achieves both increased force capacity and preserved resting surface area through optimized spatial distribution of material.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Strength

If the outer diameter of the locking ring is increased to avoid excessive radial compression during insertion, then plastic deformation is avoided, but the deformation required to introduce the ring in the seat is reduced limiting elasticity

Engineering Contradiction:
Improveresistance to plastic deformationVSAvoidelasticity
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The locking ring employs non-uniform thickness distribution where thicker sections provide resistance to plastic deformation during insertion while thinner sections maintain high elasticity for the expansion and compression functions. This local quality variation allows the ring to be introduced without excessive radial compression that would cause plastic deformation, while still providing sufficient elasticity for its operational function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The design changes the geometric parameters of the locking ring, specifically the outer diameter and thickness distribution, to optimize the balance between strength and elasticity. By carefully selecting and varying these parameters, the ring achieves sufficient strength to avoid plastic deformation during insertion while maintaining adequate elasticity for expansion in the seat and compression of the stator unit.

Inventive Principle:
Principle #35Parameter changes

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

Enables higher compression forces to be applied to the stator unit, preventing leakage and extending the pump's operational range without deforming the locking ring or tubular case, thus enhancing pump reliability and efficiency.

Implementation Method 1

a locking ring (5) that can be associated with the inner surface (15) of the tubular case (3)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The compression of the stator unit is achieved using a thrust unit that is interposed between the elastic locking ring and the stator unit and that can expand in the axial direction so as to compress the stator unit.

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2366904B1Compression device for the stator unit of a pump
Publication Date: 2014.03.05 CALPEDA
  • EP2366904B1 patent drawingFigure 1
  • EP2366904B1 patent drawingFigure 2~3
  • EP2366904B1 patent drawingFigure 4

AI summary

The invention is a compression device (2) for compressing the stator unit (17) of a pump (1), comprising: a tubular case (3) defining a longitudinal axis (X), a locking ring (5), constraining means (4) suited to constrain the locking ring (5) inside the tubular case (3) according to the direction of the longitudinal axis (X), a thrust unit (7) provided with a reference surface (12a) that can be positioned against the locking ring (5), which is suited to be expanded in an expansion direction (Y) perpendicular to the reference surface (12a), a counteracting element (8) that can be positioned against the locking ring (5) on the side opposite to the thrust unit (7), connection means (9) for connecting the counteracting element (8) to the thrust unit (7), suited to move the counteracting element (8) towards the thrust unit (7) to arrange them against the opposite sides of the locking ring (5).