Vacuum Pump Silencer Layout Using Destructive Interference

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Solution Overview

Problem

Existing silencers for vacuum pumps are complex in design and require significant space, lacking a simple and compact solution for sound wave attenuation.

Innovation Solution

A silencer with a multi-part design comprising ring-shaped parts connected to form a housing, utilizing destructive interference through linear recesses in the parts to attenuate sound waves, with channels aligned to specific wavelengths for effective noise cancellation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional silencer designs (multiple pipes, helical bypass channels) are used to achieve sound wave attenuation through interference effects, then sound attenuation is achieved, but the structure becomes complex and assembly becomes labor-intensive

Engineering Contradiction:
Improvesound wave attenuationVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The silencer is divided into multiple modular parts (first part, second part, third part) that can be manufactured separately and assembled together. Each part contains specific channel structures (first central channel, second central channel, bypass channels) that work together to achieve sound attenuation while simplifying manufacturing and assembly processes

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bypass channels are integrated within the housing structure formed by the first and second parts, with the third part positioned between them. This nested arrangement allows multiple functional channels to coexist in a compact configuration, achieving complex acoustic functionality without increasing overall structural complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If conventional silencer designs with multiple components are used to achieve sound wave attenuation, then sound attenuation is achieved, but the space occupied increases

Engineering Contradiction:
Improvesound wave attenuationVSAvoidspace occupied
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The silencer utilizes three-dimensional spatial arrangement of channels and parts to achieve efficient sound attenuation in a compact volume. The bypass channels are positioned between the first and second parts, creating a compact layered structure that maximizes acoustic functionality within minimal space

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

3Ease of manufacture

If simple monolithic designs are used for silencers, then manufacturing is easier, but sound wave attenuation effectiveness is reduced

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidsound wave attenuation
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The silencer is segmented into multiple manufacturable parts that can be produced using standard casting processes (aluminum, zinc, or plastic). This segmentation allows each part to be manufactured independently with simple tooling, while the assembled structure provides the complex multi-channel configuration needed for effective sound attenuation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design allows flexibility in material selection (aluminum, aluminum alloys, zinc, zinc alloys, or plastic) and dimensional parameters (channel lengths, diameters, and configurations) to optimize both manufacturing ease and acoustic performance for different application requirements

Inventive Principle:
Principle #35Parameter changes

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 silencer achieves efficient sound wave attenuation with a simple and compact design, suitable for vacuum pumps, utilizing aluminum, aluminum alloys, zinc, zinc alloys, or plastic castings for easy manufacturing.

Implementation Method 1

The invention also utilizes the principle of destructive interference to dampen or cancel out the sound waves

Methodology Applied
Scientific EffectDestructive interference: Interference

Implementation Method 2

Waves entering the branch lines are reflected at these closed ends. The reflections travel back into the main line, causing attenuation

Methodology Applied
Scientific EffectSound wave reflection: Reflection

Data Source

PatentEP4127480B1Silencer for a vacuum pump and vacuum pump provided with such a silencer
Publication Date: 2026.01.28 HELLA GMBH & CO KGAA
  • EP4127480B1 patent drawingFigure 1~2
  • EP4127480B1 patent drawingFigure 3~4
  • EP4127480B1 patent drawing

AI summary

The present invention relates to a silencer (S) for a vacuum pump (P) - having a first port (1) for a gas flow, - having a second port (2) for the gas flow and - having a pipe arrangement (3) between the first port (1) and the second port (2), wherein the silencer (S) is tuned for damping sound waves with a selected wavelength of (λ), wherein the pipe arrangement (3) comprises - a first pipe (31) which is connected to the first port (1), - a second pipe (32) which is connected to the second port (2), and - two central pipes (33, 34), wherein the central pipes (33, 34) are connected at a first end to the pipe (31) on the side of the first port (1) and at a second end to the pipe (32) on the side of the second port (2), and wherein a first central pipe (33) of the two central pipes (33, 34) has a first length (l1) and the second central pipe (34) of the two central pipes (33, 34) has a second length (l2) which is longer or shorter than the first length (l1) by half (λ/2) of the selected wavelength (λ).