Cylindrical Air Purifier Fan Housing to Prevent Backflow

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Solution Overview

Problem

Existing air purifiers face a reduction in airflow due to backflow into the space between the fan and fan housing, which limits the overall air discharge efficiency.

Innovation Solution

The air purifier design includes a cylindrical case with air suction ports, a filter, a fan, and a fan housing with a cover that protrudes above the fan to prevent backflow, along with a fan inlet bent inward and upward, and a shroud with specific protrusions to minimize airflow into the gap between the fan and fan housing, ensuring maximum airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If air is discharged upward from a 360-degree direction using a blowing fan, then air purification efficiency is improved, but air backflows into the space between the fan and fan housing causing reduced airflow

Engineering Contradiction:
Improveair purification efficiencyVSAvoidairflow amount
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent extracts the harmful backflow air from the system by introducing a cover that protrudes into the fan space, separating the backflow path from the main airflow path. This allows the backflow to be directed away from the fan housing gap, preventing it from reducing the effective airflow amount while maintaining the 360-degree air discharge capability for purification efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The cover acts as an intermediary element between the fan and fan housing. It protrudes into the fan space to intercept and redirect the backflow air, serving as a mediator that prevents direct contact between the backflow and the fan housing gap, thereby resolving the contradiction between maintaining high airflow and preventing backflow.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the fan is disposed close to the fan housing to maximize space utilization, then device compactness is improved, but air backflow into the gap increases reducing airflow efficiency

Engineering Contradiction:
Improvedevice compactnessVSAvoidairflow efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The patent solves the spatial conflict by extending the cover in the radial dimension into the fan space. This dimensional extension allows the cover to intercept backflow air without increasing the axial height of the device, thus maintaining compactness while improving airflow efficiency by preventing backflow into the fan housing gap.

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

3Productivity

If the cover protrudes high above the fan to effectively block backflow, then backflow prevention is improved, but device height increases

Engineering Contradiction:
Improvebackflow preventionVSAvoiddevice height
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The cover is designed with local quality differentiation - it protrudes radially into the fan space at critical locations where backflow occurs, rather than uniformly increasing the overall device height. This localized approach provides effective backflow prevention at the specific gap areas while minimizing the impact on overall device dimensions.

Inventive Principle:
Principle #3Local quality

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 maximizes airflow by reducing backflow and enhancing the amount of air blown, thereby improving the air purifier's efficiency in purifying indoor spaces.

Implementation Method 1

a fan disposed above the filter and flowing the air introduced through the air suction port in an upward direction; a fan motor disposed above the fan and rotating the fan

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

a cover protruding from the fan housing into the fan space so as to be disposed outside the fan, wherein a lower end of the fan is disposed by a certain distance from a lower wall of the fan housing to an upper wall, and the cover protrudes above the lower end of the fan from the lower wall of the fan housing. Accordingly, the cover can prevent the backflow of air generated into a distance formed between the fan and the fan housing.

Methodology Applied
Scientific EffectPhysical barrier blocking: Physical Containment

Data Source

PatentEP3875768B1Air purifier
Publication Date: 2023.06.21 LG ELECTRONICS INC
  • EP3875768B1 patent drawingFigure 1
  • EP3875768B1 patent drawingFigure 2
  • EP3875768B1 patent drawingFigure 3

AI summary

The present disclosure related to an air purifier. The air purifier of the present disclosure includes: a case having a cylindrical shape and having a plurality of air suction ports formed in a circumferential wall; a filter disposed inside the case and filtering foreign matter in an air introduced through the air suction port; a fan disposed above the filter and flowing the air introduced through the air suction port in an upward direction; a fan housing disposed above the filter and forming a fan space in which the fan is disposed; a fan motor disposed above the fan and rotating the fan; and a cover protruding from the fan housing into the fan space so as to be disposed outside the fan, wherein a lower end of the fan is disposed by a certain distance from a lower wall of the fan housing to an upper wall, and the cover protrudes above the lower end of the fan from the lower wall of the fan housing.