Suction Unit Chamber Noise Reduction via Area Expansion

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Solution Overview

Problem

Existing suction machines face challenges in operating effectively while minimizing noise, particularly in wet and dry vacuum applications, where noise reduction is essential without using additional absorption materials.

Innovation Solution

The suction unit incorporates a blower device with a tangentially arranged outlet pipe that opens into a chamber with a large cavity volume, providing a significant area expansion for process air, which leads to partial sound absorption and noise reduction. This design includes a hood for fluid-tight separation of process air and cooling air, along with a sound mirror and blow-out shield for enhanced noise reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a conventional blower outlet design is used, then the device complexity is low, but the noise level is high

Engineering Contradiction:
Improvenoise levelVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A chamber is introduced as an intermediary component between the blower outlet and the external environment. This chamber with cavity volume receives the process air from the blower and allows it to expand and dissipate before discharge, thereby reducing noise without requiring complex active noise control systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The outlet cross-section is expanded into a three-dimensional chamber with cavity volume. This dimensional transition from a simple outlet opening to a volumetric chamber provides space for sound wave propagation and dissipation, effectively reducing noise while maintaining relatively simple device structure

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

2Object-affected harmful factors

If absorption materials are added to reduce noise, then the noise level is reduced, but the device complexity and material requirements increase

Engineering Contradiction:
Improvenoise levelVSAvoidabsorption materials
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The chamber structure itself serves the noise reduction function without requiring additional absorption materials. The cavity volume and expanded surface area create conditions for natural sound dissipation through pressure equalization and wave interference, making the system self-sufficient for noise control

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The high-velocity process air from the blower, which normally creates noise, is converted into a beneficial flow pattern within the chamber. The sudden expansion causes the air to fill the chamber and dissipate energy through turbulence and pressure equalization, transforming the harmful noise-generating flow into a noise-reducing mechanism

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively reduces noise levels by up to 7 dB without using additional absorption materials, ensuring efficient operation and high electrical safety for wet and dry vacuum cleaners.

Implementation Method 1

Before being released to the outside, the exhaust air from the process must pass through this cavity. This results in partial sound absorption, which leads to a reduction in noise.

Methodology Applied
Scientific EffectSound absorption: Acoustic Absorption

Data Source

PatentEP2828535B1Suction unit and suction machine
Publication Date: 2020.05.20 ALFRED KARCHER SE & CO KG
  • EP2828535B1 patent drawingFigure 1
  • EP2828535B1 patent drawingFigure 2
  • EP2828535B1 patent drawingFigure 3

AI summary

The invention relates to a suction unit for a suction machine, comprising a motor device and a fan device for process air driven by the motor device, wherein one outlet of the fan device opens into a chamber with an empty space volume of at least 2 L.