Roots Pump Connecting Channels in Intermediate Walls

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Solution Overview

Problem

Roots pumps have a complex and costly design due to large housing volumes required for connecting channels, leading to high external dimensions and material usage, which complicates manufacturing and increases costs.

Innovation Solution

The Roots pump design features multi-tooth rotary piston pairs with connecting channels arranged in intermediate walls, reducing external dimensions and material usage, and allowing for simpler production of straight or circular-cylindrical channels, eliminating the need for curved channels outside the piston chambers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If connecting channels are arranged radially outside the piston chambers, then gas can be conveyed between pump stages, but the housing volume and external dimensions become large

Engineering Contradiction:
Improvehousing volumeVSAvoidmanufacturing complexity
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The connecting channels are relocated from a radial arrangement outside the piston chambers to an axial arrangement within the intermediate partitions. This dimensional change allows the channels to be integrated into the partition structure, significantly reducing the housing volume and external dimensions while simplifying the manufacturing process by eliminating complex curved channel geometries.

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

2Quantity of substance

If connecting channels are arranged in the housing surrounding pump chambers, then gas transport between stages is achieved, but the amount of metal used increases

Engineering Contradiction:
Improvematerial usageVSAvoidchannel design complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The connecting channels are merged with the intermediate partitions that separate adjacent pump stages. Instead of being separate components arranged in the housing, the channels are now integral parts of the partition structure. This merging reduces the total amount of metal required while simultaneously simplifying the design by eliminating complex curved channel geometries.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If curved connecting channels are provided radially outside piston chambers, then gas can be conveyed between stages, but production becomes technically difficult

Engineering Contradiction:
Improveproduction simplicityVSAvoidchannel geometry
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The channel geometry is changed from curved radial channels to straight axial channels by relocating them to the intermediate partitions. This dimensional change transforms the complex curved geometry into simple straight or circular-cylindrical channels that can be easily produced using standard drilling or boring operations, significantly simplifying the manufacturing process.

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

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 design results in a more compact, cost-effective, and lightweight pump with reduced pressure losses and lower maintenance requirements, as well as reduced power consumption and equalized load peaks and heat of compression.

Implementation Method 1

The two rotary pistons are driven in opposite directions, so that gas is sucked in through the individual chambers created through a main inlet and expelled again through a main outlet

Methodology Applied
Scientific EffectRotational motion:

Implementation Method 2

the connecting channels can be arranged in the housing of the Roots pump, the connecting channels surrounding the pump chambers in which the rotary pistons are arranged or being arranged radially outside the pump chambers

Methodology Applied
Scientific EffectFluid flow through channels:

Implementation Method 3

the connecting channels are arranged in intermediate walls which separate adjacent pump stages from one another

Methodology Applied
Scientific EffectPhysical separation:

Data Source

PatentEP2745015B1Roots pump
Publication Date: 2021.10.06 LEYBOLD AG
  • EP2745015B1 patent drawingFigure 1~2
  • EP2745015B1 patent drawingFigure 3~4
  • EP2745015B1 patent drawingFigure 5

AI summary

A Roots pump has a plurality of multiple-tooth rotary piston pairs (10, 48, 49) which form in each case one pump stage (50, 52, 54, 56, 58, 60). Adjacent pump stages (50, 52, 54, 56, 58, 60) are connected to one another via connecting ducts (30, 34, 77, 84, 86, 88, 90). In order to reduce the production costs, it is provided according to the invention to arrange the connecting ducts (30, 34, 77, 84, 86, 88, 90) in intermediate walls (74, 76, 78, 80, 82) which separate adjacent pump stages (50, 52, 54, 56, 58, 60) from one another.