Flexible Scroll Pump Design for Leakage Reduction

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Solution Overview

Problem

Traditional scroll pumps face efficiency issues due to gas leakage through clearances between scrolls, requiring high precision and costly manufacturing, with tip seals wearing out and generating debris over time.

Innovation Solution

A scroll pump design utilizing a single flexible scroll that distorts to form constrictions within channels, reducing tolerance requirements and potentially leading to a low-cost, long-life pump, with varying stiffness along the flexible member to address curvature-related issues and eliminate the need for tip seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two rigid scrolls are used in a scroll pump, then the pump can achieve fluid pumping function, but gas leakage through clearances between scrolls reduces efficiency and requires high manufacturing precision

Engineering Contradiction:
Improvepumping efficiencyVSAvoidscroll tolerance
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces rigid scrolls with a flexible membrane that can dynamically conform to the pumping chamber geometry. This flexible membrane eliminates the need for high-precision rigid scroll manufacturing while maintaining sealing effectiveness, as the membrane naturally adapts to clearance variations through its flexibility.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the physical state of the scroll from rigid to flexible, allowing the membrane to dynamically adjust its shape and position. This parameter change enables the system to tolerate manufacturing variations while maintaining pumping efficiency by allowing the membrane to conform to the actual chamber geometry during operation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If tip seals are used to reduce leakage between spiral walls and opposing plates, then sealing efficiency improves, but the seals wear out over time and generate debris

Engineering Contradiction:
Improvesealing efficiencyVSAvoidseal lifetime
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent removes the tip seals entirely from the system by using a flexible membrane that forms the pumping chamber walls themselves. The membrane's flexibility allows it to maintain sealing contact without requiring separate seal components, thereby eliminating the wear and debris generation associated with traditional tip seals.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible membrane serves multiple functions simultaneously: it forms the pumping chamber walls, provides sealing contact to prevent leakage, and accommodates motion variations. This self-service approach eliminates the need for separate tip seals that would otherwise be required to provide sealing functionality.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If a single flexible scroll is used instead of two rigid scrolls, then manufacturing costs decrease and tolerance requirements are reduced, but the flexible member must be driven to process around a rotating path

Engineering Contradiction:
Improvemanufacturing costVSAvoiddriving mechanism
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines the functions of two rigid scrolls into a single flexible membrane, reducing the number of components and simplifying manufacturing. The flexible membrane performs both the structural and sealing functions that previously required two separate rigid scrolls, thereby reducing manufacturing costs and tolerance requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a dynamic flexible membrane that can change its shape and position during operation, as opposed to static rigid scrolls. This dynamic behavior allows the single membrane to achieve the pumping action previously requiring two rigid components, simplifying the overall structure while maintaining functionality.

Inventive Principle:
Principle #15Dynamics

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

The flexible scroll design reduces leakage, lowers manufacturing costs, and extends pump lifetime by minimizing wear and friction, while allowing for various designs to accommodate different pumping capacities and pressure differentials.

Implementation Method 1

a flexible member arranged between and substantially perpendicular to said two plates, said flexible member having a spiral form... a driving member configured to drive an inner portion of said flexible member such that said inner portion processes around a path within said outer member... said reduced distance causes a cross section of said at least one channel to be reduced and a constriction to be formed

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3924623B1Scroll pump
Publication Date: 2024.04.03 EDWARDS LTD
  • EP3924623B1 patent drawingFigure 1
  • EP3924623B1 patent drawingFigure 2
  • EP3924623B1 patent drawingFigure 3

AI summary

A pump comprising: two plates mounted parallel to and separated from each other; an outer member surrounding at least one flexible member arranged between and substantially perpendicular to said two plates. The flexible member has a spiral form and forms at least one side wall of a channel running from an inlet to an outlet of the pump. A driving member is configured to drive an inner portion of said flexible member such that said inner portion processes around a path within said outer member such that a distance between said inner portion and said outer member is reduced on one side of said inner portion and increased on the other side of said inner portion. The reduced distance between the inner portion and outer member causes a cross section of the at least one channel to be reduced and a constriction to be formed in the at least one channel, movement of the inner portion causing corresponding movement of the restriction such that a fluid is pushed along the at least one channel as the inner portion processes.