Uniaxial Eccentric Screw Pump Stator Separation

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Solution Overview

Problem

Conventional uniaxial eccentric screw pumps face challenges in separating and recovering the stator's outer cylinder and lining member, leading to positional shifts, deformation, uneven wear, and unstable discharge due to fixed bonding and non-bonded configurations.

Innovation Solution

A uniaxial eccentric screw pump design where the outer cylinder is mounted in a pressed state on the liner portion without adhesives, with collar portions and end studs to prevent axial shrinkage and positional shifts, allowing easy separation and recovery, and stabilizing the discharge amount.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the outer cylinder and lining member are fixed through bonding, then positional shifts and deformation are prevented, but separation and recovery require considerable time and effort

Engineering Contradiction:
Improvepositional stabilityVSAvoidseparation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The stator is divided into two separable components: the outer cylinder and the lining member. This segmentation allows the components to be easily separated for recovery while maintaining their functional integrity during operation. The lining member can be independently removed from the outer cylinder without requiring bonding separation processes.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the outer cylinder is mounted simply in a non-bonded state on the lining member, then separation and recovery are easy, but positional shifts and deformation occur

Engineering Contradiction:
Improveseparation easeVSAvoidpositional stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

Collar portions are introduced as intermediary structures at the axial ends of the lining member. These collar portions engage with corresponding structures in the outer cylinder to prevent axial displacement and positional shifts, while allowing the components to remain separable without bonding.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the lining member is allowed to expand and shrink axially, then separation is easier, but the inner diameter varies and causes uneven wear

Engineering Contradiction:
Improveseparation easeVSAvoidinner diameter uniformity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The collar portions and engagement structures are designed to pre-compress the lining member axially, counteracting the tendency of the lining member to expand and shrink during operation. This preliminary constraint maintains a uniform inner diameter throughout the service life of the pump, preventing uneven wear while still allowing for easy separation when needed.

Inventive Principle:
Principle #9Preliminary anti-action

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 easy separation and recovery of the stator components, prevents uneven wear and positional shifts, and stabilizes the discharge amount by maintaining a uniform inner diameter of the liner portion.

Implementation Method 1

the outer cylinder portion is mounted in the pressed state on the liner portion

Methodology Applied
Scientific EffectPress fit: Mechanical Force

Data Source

PatentEP2578882B1Uniaxial eccentric screw pump
Publication Date: 2020.01.22 NETZSCH PUMPEN & SYST
  • EP2578882B1 patent drawingFigure 1
  • EP2578882B1 patent drawingFigure 2(a)~2(b)
  • EP2578882B1 patent drawingFigure 3

AI summary

Provided is a uniaxial eccentric screw pump enabling a stator to be easily separated into an outer cylinder and a lining member, and being capable of solving problems such as a positional shift and deformation of the lining member, and an occurrence of uneven wear and an unstable discharge amount associated with the positional shift and deformation. A stator (20) includes: a liner portion (22) having a cylindrical shape and being integrally formed so as to have an inner peripheral surface of an internal thread type; and an outer cylinder portion (24). The liner portion (22) includes, at both end portions thereof, flange portions (26, 26) protruding radially outward, and an outer cylinder mounting portion (28) is provided between the flange portions (26, 26). The outer cylinder portion (24) is mounted in a non-bonded state on the outer cylinder mounting portion (28), and both end portions of the outer cylinder portion (24) abut on the flange portions (26, 26), respectively.