Molecular Vacuum Pump Blocking Element for Suction Control

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Solution Overview

Problem

Existing molecular vacuum pumps face challenges in efficiently and simply controlling pumping speed, particularly at specific points in the flow path, which affects the suction speed and backflow of gases, especially for different gases with varying molar masses.

Innovation Solution

Incorporating a static blocking element within the pump stage that reduces the passage cross-section at a specific point, allowing for targeted influence on suction speed and creating a difference in partial suction speeds between gases, thereby altering the ratio of backflowing gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a blocking element is provided to reduce passage cross section at a second point, then the suction speed at a first point can be specifically influenced, but the overall suction speed is reduced

Engineering Contradiction:
Improvetargeted influence on suction speedVSAvoidoverall suction speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The blocking element is positioned at a specific location (second point) within the pump stage to create a localized reduction in passage cross-section. This local modification specifically influences the suction speed at a different location (first point) without requiring global changes to the entire pump structure, enabling targeted control of gas flow characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The blocking element changes the geometric parameter of the passage cross-section at the second point, which in turn modifies the suction speed parameter at the first point. By adjusting the size and position of the blocking element, the suction speed can be precisely controlled for different gas components while maintaining overall pump functionality.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the passage cross section is locally reduced by a blocking element, then the conductance at the second point is reduced, but the suction speed at the first point can be increased for specific gases

Engineering Contradiction:
Improvedifference in partial suction speedsVSAvoidstructure modification
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The blocking element creates a localized modification in the passage cross-section at the second point, which selectively affects the flow characteristics of different gas components. This local change enables precise control over the difference in partial suction speeds for gases with different molar masses without requiring complex global structural changes.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By modifying the geometric parameter of the passage cross-section through the blocking element, the conductance at the second point is changed, which subsequently alters the suction speed parameters at the first point. This parameter change approach enables precise differentiation in suction speeds for different gas species.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If a blocking element is provided to influence suction speed, then the backflow ratio of different gases is altered, but the overall pumping performance is reduced

Engineering Contradiction:
Improvegas separation capabilityVSAvoidpumping speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The blocking element is positioned at a specific location within the pump stage to create a localized effect on gas flow. This local modification selectively influences the backflow characteristics of different gas components based on their molar masses, enabling gas separation capability without requiring changes to the entire pump system.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The blocking element changes the passage cross-section parameter at the second point, which subsequently modifies the backflow ratio parameter for different gases at the first point. By adjusting this geometric parameter, the pump can adapt its gas separation capability while maintaining acceptable overall pumping performance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3851680B1Molecular vacuum pump and method for influencing the suction performance of same
Publication Date: 2023.09.13 PFEIFFER VACUUM TECH AG
  • EP3851680B1 patent drawingFigure 1
  • EP3851680B1 patent drawingFigure 2
  • EP3851680B1 patent drawingFigure 3

AI summary

The invention relates to a method for influencing the pumping speed of a molecular vacuum pump, which comprises at least one molecular pumping stage by means of which a gaseous medium can be pumped along a flow path from an inlet to an outlet of the molecular vacuum pump, wherein the pumping stage has a pumping direction and a passage cross-section transverse to the pumping direction, wherein the influencing of the pumping speed takes place at a first point in the flow path of the molecular vacuum pump, namely by providing a blocking element at a second point in the flow path of the molecular vacuum pump, different from the first point, by which the passage cross-section is locally reduced.