Multi-Inlet Vacuum Pump Layout for Higher Pumping Speed

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Solution Overview

Problem

The existing vacuum systems, particularly in applications like mass spectrometry, are limited by the pumping speed of the lowest pressure stage, which is constrained by the rotor diameter and rotational speed, leading to increased costs and complexity, and the need for larger pumps to achieve higher pumping speeds.

Innovation Solution

The introduction of a third pumping stage with a rotor element on a common rotor shaft, connected downstream of the second pumping stage and upstream of a conduit, allows for increased pumping speed without increasing rotor diameter or rotation speed, by bypassing the second pumping stage and using a direction element to prevent gas flow between stages, thereby enhancing the overall pumping speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rotor diameter is increased to achieve higher pumping speed, then the pumping speed is improved, but the costs and rotor dynamics challenges increase

Engineering Contradiction:
Improvepumping speedVSAvoid rotor dynamics challenges
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The pump is divided into multiple independent pumping stages (first, second, and third stages) that can be connected in parallel. Each stage processes gas independently, allowing the system to achieve higher total pumping speed without increasing the diameter or rotational speed of individual rotors. This segmentation resolves the contradiction by distributing the pumping workload across multiple smaller units rather than relying on a single large rotor.

Inventive Principle:
Principle #1Segmentation

2Productivity

If the rotor diameter is increased to achieve higher pumping speed, then the pumping speed is improved, but the costs increase

Engineering Contradiction:
Improvepumping speedVSAvoidcosts
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The pump is divided into multiple independent pumping stages (first, second, and third stages) that can be connected in parallel. Each stage processes gas independently, allowing the system to achieve higher total pumping speed without increasing the diameter or rotational speed of individual rotors. This segmentation resolves the contradiction by distributing the pumping workload across multiple smaller units rather than relying on a single large rotor.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the rotational speed is increased to achieve higher pumping speed, then the pumping speed is improved, but the centrifugal forces and material creep worsen

Engineering Contradiction:
Improvepumping speedVSAvoidcentrifugal forces
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The pump is divided into multiple independent pumping stages (first, second, and third stages) that can be connected in parallel. Each stage processes gas independently, allowing the system to achieve higher total pumping speed without increasing the diameter or rotational speed of individual rotors. This segmentation resolves the contradiction by distributing the pumping workload across multiple smaller units rather than relying on a single large rotor.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If a single pumping stage is used, then the device complexity is reduced, but the pumping speed is limited

Engineering Contradiction:
Improvepump structureVSAvoidpumping speed
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

Multiple pumping stages (first, second, and third stages) are merged into a single integrated pump system with a common rotor shaft. The stages are connected in parallel with separate inlets and outlets, allowing them to work simultaneously. This merging approach achieves high pumping speed while maintaining relatively simple structure through the shared rotor shaft and integrated housing.

Inventive Principle:
Principle #5Merging (Combining)

5Force

If the rotor length is increased instead of diameter, then the centrifugal forces are reduced, but the rotor dynamics challenges increase

Engineering Contradiction:
Improvecentrifugal forcesVSAvoidrotor dynamics
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The pump is divided into multiple independent pumping stages (first, second, and third stages) that can be connected in parallel. Each stage processes gas independently, allowing the system to achieve higher total pumping speed without increasing the diameter or rotational speed of individual rotors. This segmentation resolves the contradiction by distributing the pumping workload across multiple smaller units rather than relying on a single large rotor.

Inventive Principle:
Principle #1Segmentation

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 achieves a significant 70% increase in pumping speed without increasing costs or size, maintaining rotor diameter and rotation speed, and reduces centrifugal forces by lengthening the rotor rather than increasing its diameter, thus improving vacuum chamber pressure without the associated costs and dynamic issues.

Implementation Method 1

a vacuum pump, preferably turbomolecular pump... each pumping stage comprising at least one rotor element being arranged on a common rotor shaft

Methodology Applied
Scientific EffectTurbomolecular pumping:

Data Source

PatentEP3767110B1Vacuum system
Publication Date: 2024.09.18 PFEIFFER VACUUM GMBH
  • EP3767110B1 patent drawingFigure 1~3
  • EP3767110B1 patent drawingFigure 4~5
  • EP3767110B1 patent drawingFigure 6~7

AI summary

The invention relates to a vacuum system, comprising a vacuum pump, preferably turbomolecular pump, and at least one vacuum chamber, wherein the vacuum pump comprises: at least a first and a second inlet and a common outlet; at least a first and a second pumping stage, each pumping stage comprising at least one rotor element being arranged on a common rotor shaft, wherein the first inlet is connected to an upstream end of the first pumping stage and the second inlet is connected to an upstream end of the second pumping stage; a direction element for preventing a gas flow from a downstream end of the first pumping stage to the second inlet; a conduit having a conduit inlet and a conduit outlet, wherein the conduit inlet is connected to the downstream end of the first pumping stage and the conduit outlet is connected to a location downstream of the second pumping stage; wherein the first inlet and the second inlet of the pump are connected to the same vacuum chamber.