Compact Dental Suction Unit High-Speed Motor Noise Reduction

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Solution Overview

Problem

Conventional suction units used in dental and medical practices are large, noisy, and require significant structural changes due to their size, making them impractical for direct use at the workplace, and they struggle to generate high negative pressure with small diameter cannulas.

Innovation Solution

A compact suction unit utilizing a high-speed electrically commutated motor driven at over 20,000 rpm, combined with soundproofing materials like talc-filled plastics and a coolant system for heat dissipation, allowing for efficient sound absorption and reduced noise, enabling the suction unit to be lightweight and easily transportable while maintaining high suction pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a side-channel machine is used to generate high vacuum, then sufficient suction pressure is achieved, but the machine becomes large and requires structural modifications to the building

Engineering Contradiction:
Improvesuction pressureVSAvoidmachine size
Core Design Contradiction:
Stress or pressureVSVolume of moving object

Solution Approach 1:

The patent changes the operating parameters by using a radial conveying element with significantly reduced diameter (3-15 cm compared to conventional large diameters) and compensates by increasing rotational speed to over 20,000 rpm, achieving the same vacuum effect in a compact form

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention transitions from conventional side-channel machines operating at lower speeds with large diameters to a high-speed radial conveying element, effectively changing the dimensional characteristics by reducing the radial dimension while increasing the temporal dimension (rotational speed)

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

2Stress or pressure

If a side-channel machine is used to generate high vacuum, then sufficient suction pressure is achieved, but the machine becomes noisy and requires separate rooms

Engineering Contradiction:
Improvesuction pressureVSAvoidnoise
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the radial conveying element from the conventional side-channel machine design and integrates it with a high-speed motor, separating the vacuum generation function from the noisy conventional machinery while maintaining effectiveness

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

By changing the operational parameters to high-speed rotation of a compact radial element, the patent achieves the same suction pressure with significantly reduced noise levels, eliminating the need for separate rooms or structural modifications

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If a small radial conveying element is used to reduce machine size, then compact dimensions are achieved, but sufficient suction pressure cannot be generated at usual motor speeds

Engineering Contradiction:
Improvemachine sizeVSAvoidsuction pressure
Core Design Contradiction:
Volume of moving objectVSStress or pressure

Solution Approach 1:

The patent applies preliminary anti-action by using sound-insulating material that also serves as thermal insulation, preventing heat buildup before it becomes a problem, while the high-speed operation prevents suction pressure deficiency before it occurs

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention changes the speed parameter from conventional motor speeds to over 20,000 rpm, which compensates for the small radial dimensions and generates sufficient suction pressure in the compact machine

Inventive Principle:
Principle #35Parameter changes

4Object-generated harmful factors

If sound-insulating material is added to the vacuum cleaner, then noise is reduced, but weight increases and portability decreases

Engineering Contradiction:
ImprovenoiseVSAvoidweight
Core Design Contradiction:
Object-generated harmful factorsVSWeight of moving object

Solution Approach 1:

The patent applies multi-functionality by using sound-insulating material that simultaneously provides thermal insulation, eliminating the need for separate thermal insulation layers and reducing overall weight while maintaining noise reduction

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the sound insulation function with thermal insulation by using the same material for both purposes, and also combines it with the housing structure, reducing the total number of components and weight

Inventive Principle:
Principle #5Merging (Combining)

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 allows for a compact, quiet, and efficient suction unit that can be easily integrated into a dental workstation, providing effective sound insulation and high suction pressure with minimal noise and weight, enabling targeted suction without the need for remote connections or separate rooms.

Implementation Method 1

a radial conveying element, such as a rotary impeller, which has small dimensions ranging from 3 to 8 or up to 15 cm. Such a radial conveying element would not be sufficient to generate the desired suction pressure at the usual speeds of electric motors (around 3000 rpm). Therefore, this vacuum cleaner is driven by a high-speed, preferably electrically commutated motor (EC motor), which rotates at a significantly higher speed than the mains frequency (more than 20,000 rpm)

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The sound insulation prevents noise generated by the suction machine from being transmitted to the surrounding environment. The term 'sound-insulating' here refers to any material that absorbs sound or reduces the transmission of sound

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Implementation Method 3

chambers defined by boundary walls, in which the sound-insulating material is located, simultaneously form flow paths through which a coolant flow can move. Such a coolant flow carries away heat generated in the electric motor and the vacuum cleaner by convection

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2686559B1Suction unit
Publication Date: 2019.11.06 DURR DENTAL GMBH & CO KG
  • EP2686559B1 patent drawingFigure 1
  • EP2686559B1 patent drawingFigure 2~3
  • EP2686559B1 patent drawingFigure 4

AI summary

The invention relates to a compact suction unit (32) suitable for dental and medical purposes, wherein the suction machine is equipped with radial impellers (132, 134) having small diameters, which are driven at high speed by an electrically commutated electric motor (36). For the purpose of sound insulation, the suction machine (34) and the electric motor (36) have a respective water jacket (90; 110) that is limited on the outside by a housing (58) that is made of sound-absorbing plastic material.