Vacuum Pump Inflow Suppressing Walls Gas Retention

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Solution Overview

Problem

Vacuum pumps with thread groove mechanisms face issues with gas retention at the exhaust side outlet, leading to decreased compression ratios and pump performance due to gas solidification and deposition, which affects their efficiency over time.

Innovation Solution

The implementation of gas retention suppressing means, such as inflow suppressing walls and turning retention suppressing walls, which prevent gas from flowing into the thread groove in the rotating direction and guide it back to the axis, thereby reducing retention and deposition at the exhaust side outlet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If gas flows into the thread groove at the exhaust side outlet, then the compression ratio is improved, but gas retention occurs causing deposition and performance deterioration

Engineering Contradiction:
Improvecompression ratioVSAvoidpump performance stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The harmful gas flow that causes retention is extracted and redirected away from the exhaust side outlet. The gas guide wall separates the harmful backflow from the useful compression flow, allowing the beneficial gas movement to continue while eliminating the detrimental retention effect.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A gas guide wall is introduced as an intermediary structure between the thread groove and the exhaust side outlet. This wall acts as a mediator that redirects gas flow in a controlled manner, preventing direct contact between the gas and the problematic outlet region while maintaining compression efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the thread groove structure is simplified, then the device complexity is reduced, but gas retention and deposition occur

Engineering Contradiction:
Improvethread groove structureVSAvoidgas deposition
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The thread groove structure is segmented by introducing the gas guide wall, which divides the continuous groove into functional zones. This segmentation allows different sections to perform different functions: one section for compression and another for controlled exhaust, preventing gas retention without requiring complete structural redesign.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution adds a dimensional element (the gas guide wall extending into the groove) rather than modifying the existing two-dimensional groove geometry. This third-dimensional approach prevents gas retention by creating a flow barrier without significantly complicating the base structure.

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

3Ease of operation

If gas flows back in the rotating direction, then the pump maintains simple structure, but gas retention occurs reducing pump performance

Engineering Contradiction:
Improvegas flow pathVSAvoidpump performance
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

Instead of allowing gas to flow back in the rotating direction (the natural but harmful path), the gas guide wall inverts this flow pattern by redirecting gas in the opposite direction or along a controlled path that avoids retention zones, thereby maintaining performance.

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

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

This configuration effectively suppresses gas retention and deposition, maintaining pump performance by ensuring smooth gas exhaustion and preventing an increase in outlet pressure, thus extending the operational lifespan of the vacuum pump.

Implementation Method 1

a rotor rotatable in a predetermined rotating direction

Methodology Applied
Scientific EffectRotational motion:

Implementation Method 2

an inflow suppressing wall formed by widening an exhaust side end portion of the ridge portion on the exhaust side in the gas exhaust direction greater than an intake side end portion of the ridge portion on the intake side in the gas exhaust direction

Methodology Applied
Scientific EffectFlow blockage:

Implementation Method 3

When the gas is retained in the exhaust side outlet of the thread groove as explained above, the retained gas solidifies under a high pressure, a gas product is deposited

Methodology Applied
Scientific EffectGas solidification:

Data Source

PatentEP3018354B1Vacuum pump
Publication Date: 2020.10.14 EDWARDS JAPAN
  • EP3018354B1 patent drawingFigure 1
  • EP3018354B1 patent drawingFigure 2
  • EP3018354B1 patent drawingFigure 3(a)~3(b)

AI summary

A vacuum pump is provided, which suppresses occurrence of a gas product in an exhaust side outlet of a thread groove and maintains pump performance over a long period. The vacuum pump includes inflow suppressing walls formed by widening greater an exhaust side end portion of ridge portions, extended along a gas exhaust direction on an outer circumferential surface of an inner circumference side stator, forward in a rotor rotating direction than an intake side end portion, the inflow suppressing walls suppressing retention of gas in exhaust side outlets of thread grooves engraved among the ridge portions.