Pleated Air Filter Medium With Embossed Protrusions

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Solution Overview

Problem

Air filters with pleated structures face challenges in maintaining sufficient separation between surfaces to ensure effective filtration while avoiding increased pressure drop, particularly when forming embossed protrusions with varying heights, which can lead to reduced filtering functionality and increased pressure drop due to the presence of separators.

Innovation Solution

An air-filtering medium with a pleated structure that incorporates upwind-surface and downwind-surface embossed protrusions and interval maintaining members, where the protrusions and members are strategically positioned to maintain surface separation and reduce pressure drop, using materials like resins or metals to enhance interval maintenance without unnecessary increase in pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If embossed protrusions with varying heights are formed on the air filter medium, then the separation between pleated surfaces is maintained, but the protrusion heights are absorbed by the film thickness reduction, making it difficult to form sufficient protrusion heights

Engineering Contradiction:
Improveprotrusion heightVSAvoidprotrusion height precision
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent performs preliminary embossing to form protrusions on the air filter medium before the pleating process. This preliminary action ensures that the protrusions are already formed with sufficient height before the film thickness is reduced during pleating, preventing the protrusion heights from being absorbed by the film thickness reduction.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the air filter medium into multiple layers, with the embossed protrusions formed on specific layers. This segmentation allows the protrusions to maintain their height independently of the overall film thickness reduction, as they are formed on discrete layers rather than the entire composite structure.

Inventive Principle:
Principle #1Segmentation

2Shape

If high protrusion heights are formed to maintain surface separation, then facing surfaces are kept apart, but the filtering function is compromised and pressure drop increases

Engineering Contradiction:
Improvesurface separation distanceVSAvoidfiltering function
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies local quality by forming embossed protrusions only at specific locations on the air filter medium, particularly at the pleat roots and crests. This localized embossing maintains surface separation where needed while preserving the filtering function in other areas, avoiding the need for high protrusion heights across the entire medium.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses partial action by forming protrusions only on certain layers or at certain locations rather than uniformly across the entire air filter medium. This partial embossing is sufficient to maintain the necessary surface separation at critical points without excessively increasing pressure drop or compromising the overall filtering function.

Inventive Principle:
Principle #16Partial or excessive action

3Shape

If separators are used to maintain intervals between pleated surfaces, then surface separation is ensured, but pressure drop increases due to the presence of separators

Engineering Contradiction:
Improveinterval maintenanceVSAvoidpressure drop
Core Design Contradiction:
ShapeVSLoss of energy

Solution Approach 1:

The patent extracts the interval maintenance function from separate mechanical separators and integrates it directly into the air filter medium structure through embossing. By taking out the need for discrete separator components and incorporating the spacing function into the medium itself, the solution eliminates the pressure drop increase associated with additional separator structures.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the interval maintenance function with the air filter medium structure by forming embossed protrusions that simultaneously serve as both the filtering medium and the spacing maintainers. This merging eliminates the need for separate separator components, thereby reducing pressure drop while ensuring proper pleat spacing.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3520872B1Air filter medium, air filter pack, and air filter unit
Publication Date: 2020.11.04 DAIKIN INDUSTRIES LTD
  • EP3520872B1 patent drawingFigure 1
  • EP3520872B1 patent drawingFigure 2~3
  • EP3520872B1 patent drawingFigure 4

AI summary

An air-filtering medium, an air filter pack, and an air filter unit, which are capable of reducing the number of portions where filtering functions can no longer be exhibited while suppressing an increase in pressure drop are provided. An air-filtering medium (30) is used in a pleated state and includes a main collecting layer (31b), a downwind-surface interval maintaining structure material (33), and an upwind-surface interval maintaining member (40). The main collecting layer (31b) includes an upwind-surface embossed protrusion (32) protruding in a thickness direction of the main collecting layer (31b). In the pleated state, the upwind-surface embossed protrusion (32) is provided at least on an upstream side of a center of the air-filtering medium (30) in a direction of airflow passing through the air-filtering medium (30), and protrudes towards an upwind-surface side. In the pleated state, the downwind-surface interval maintaining structure (33) maintains an interval between facing downwind surfaces at least at a portion on an air-flow downstream side of the center of the air-filtering medium (30) in the direction of airflow. In the pleated state, the upwind-surface interval maintaining member (40) maintains an interval between facing upwind surfaces at least at a portion on the downstream side of the center of the air-filtering medium (30) in the direction of airflow.