Air Filter Medium With Acid-Impregnated Carbon

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Solution Overview

Problem

Existing air filter media face challenges in efficiently removing basic gases like ammonia (NH3) and trimethylamine (TMA) due to high initial gas breakthroughs and high costs associated with ion exchange resins, which have poor spontaneity and higher mass-related prices compared to impregnated activated carbon.

Innovation Solution

An air filter medium combining an ion exchange layer with impregnated activated carbon particles, where the activated carbon is impregnated with inorganic acids like phosphoric acid, sulfuric acid, or hydrochloric acid, achieving improved adsorption kinetics and cost-effectiveness by optimizing grammage and arrangement of layers to enhance initial separation efficiency and prevent gas breakthroughs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If ion exchange resins are used to remove basic gases like NH3 and TMA, then adsorption capacity is improved, but initial separation efficiency deteriorates due to slow response times and high gas breakthroughs

Engineering Contradiction:
Improveadsorption capacityVSAvoidinitial separation efficiency
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The filter medium is divided into two distinct functional layers: an ion exchange layer for high-capacity adsorption and an impregnated activated carbon layer for rapid initial adsorption. This segmentation allows each layer to specialize in its strength, resolving the contradiction between capacity and initial efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite filter medium combining ion exchange particles and impregnated activated carbon particles in a layered structure. This composite approach integrates the high adsorption capacity of ion exchange resins with the fast response of impregnated activated carbon, achieving both high capacity and high initial separation efficiency.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If ion exchange resins are used for gas adsorption, then adsorption capacity is improved, but manufacturing cost increases due to three times higher mass-related price compared to impregnated activated carbon

Engineering Contradiction:
Improveadsorption capacityVSAvoidmanufacturing cost
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The filter medium is divided into two distinct functional layers: an ion exchange layer for high-capacity adsorption and an impregnated activated carbon layer for rapid initial adsorption. This segmentation allows each layer to specialize in its strength, resolving the contradiction between capacity and initial efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention optimizes the grammage of ion exchange particles to a specific range (150-350 g/m2) to achieve the required adsorption capacity at minimal cost. By carefully controlling this parameter, the filter achieves high performance while minimizing the use of expensive ion exchange material.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If higher grammage of ion exchange particles is used, then gas adsorption capacity is improved, but manufacturing cost increases

Engineering Contradiction:
Improvegas adsorption capacityVSAvoidmanufacturing cost
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The invention optimizes the grammage of ion exchange particles to a specific range (150-350 g/m2) to achieve the required adsorption capacity at minimal cost. By carefully controlling this parameter, the filter achieves high performance while minimizing the use of expensive ion exchange material.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The filter medium applies different grammage levels of ion exchange particles in different regions or layers, with the upstream side having optimized grammage for initial adsorption and the downstream side providing additional capacity. This local optimization reduces overall material cost while maintaining performance.

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

The air filter medium achieves >95% initial separation efficiency for NH3 and TMA with lower grammage of ion exchange particles, improving adsorption kinetics and maintaining gas adsorption over longer periods while being more cost-effective, and enabling coadsorption of hydrocarbons like methyl ethyl ketone.

Implementation Method 1

an impregnation layer (3) comprising impregnated activated carbon particles, wherein the impregnated activated carbon particles of the impregnation layer (3) are impregnated with an acidic impregnating agent

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the inorganic acid is selected from the group consisting of phosphoric acid, sulfuric acid, and hydrochloric acid

Methodology Applied
Scientific EffectChemisorption: Chemisorption

Implementation Method 3

an ion exchange layer (2) comprising ion exchange particles

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Data Source

PatentEP4389255A1Air filter medium, filter medium body, and filter element
Publication Date: 2024.06.26 MANN HUMMEL GMBH
  • EP4389255A1 patent drawingFigure 1~2a
  • EP4389255A1 patent drawingFigure 2b~2c
  • EP4389255A1 patent drawingFigure 3~4

AI summary

The invention relates to an air filter medium (1), in particular for a cabin air filter, an intake air filter of a fuel cell, or a vapor filter, comprising an ion exchange layer (2) comprising ion exchange particles, and an impregnation layer (3) comprising impregnated activated carbon particles. The impregnated activated carbon particles of the impregnation layer (3) are impregnated with an acidic impregnating agent comprising at least one inorganic acid, wherein the inorganic acid is selected from the group consisting of phosphoric acid, sulfuric acid, and hydrochloric acid. The basis weight of the ion exchange particles in the ion exchange layer (2) is in the range of 150 g/m² to 350 g/m². The basis weight of the impregnated activated carbon particles in the impregnation layer (3) is in the range of 150 g/m² to 350 g/m². Furthermore, a filter medium body (10) and a filter element (100) are disclosed.