Carbon Block Filter Metal Impregnation Uniformity

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Solution Overview

Problem

Existing processes for making metal impregnated carbon block filters are cumbersome and costly, with variations in metal content across blocks and high leach rates, especially when impregnating lower levels of metals like Silver or Zinc.

Innovation Solution

A process involving contacting activated carbon particles with an aqueous solution of a metal salt in the presence of Ammonium hydroxide, followed by adding a polymeric binder and molding under pressure and heat, which ensures uniform metal impregnation and reduces energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the prior art process of dipping bound blocks into aqueous solution of metal salt and precipitating metal ions is used, then higher levels of metals can be impregnated, but there is variation in the amount of impregnated metal across different blocks

Engineering Contradiction:
Improvemetal contentVSAvoiduniformity of metal distribution
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The invention applies preliminary action by mixing the metal salt solution with the carbon particles and binder before the molding process. This ensures that the metal is uniformly distributed throughout the mixture prior to block formation, eliminating the variation in metal content across different blocks that occurs when metal is applied after block formation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention merges the metal impregnation step with the block making step by combining metal salt solution, carbon particles, and binder into a single mixture that is then molded into blocks. This integration ensures uniform metal distribution throughout the block structure, resolving the contradiction between achieving high metal content and maintaining uniformity across blocks.

Inventive Principle:
Principle #5Merging (Combining)

2Quantity of substance

If separate impregnation and block making steps are used, then metal impregnation can be performed, but the cost increases due to independence of processes

Engineering Contradiction:
Improvemetal impregnationVSAvoidmanufacturing cost
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The invention combines the metal impregnation process with the block making process into a single integrated operation. By mixing metal salt solution with carbon particles and binder before molding, the process eliminates the need for separate impregnation and block making steps, thereby reducing manufacturing cost while achieving uniform metal distribution.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mixed mixture serves multiple functions simultaneously: it acts as both the block making material and the metal impregnation medium. This multi-functionality allows a single process to achieve both block formation and uniform metal distribution, reducing the number of separate operations required and lowering overall manufacturing cost.

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

3Quantity of substance

If conventional impregnation processes are used, then metal can be applied to carbon blocks, but the leach rate of metal during use is high

Engineering Contradiction:
Improvemetal contentVSAvoidmetal leach rate
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

By integrating metal impregnation with block formation through mixing metal salt solution with carbon particles and binder before molding, the metal becomes uniformly distributed and embedded within the block structure. This results in lower metal leach rates during use compared to conventional post-formation impregnation methods where metal is applied to the surface.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention changes the physical and chemical parameters during the molding process by applying heat and pressure to the mixed mixture. This transforms the metal salt solution into uniformly distributed metal impregnation within the block structure, creating a more stable and less leachable metal configuration compared to surface application methods.

Inventive Principle:
Principle #35Parameter changes

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 process achieves carbon block filters with low variation in metal content, lower metal leach rates, and enhanced absorption of organic contaminants, resulting in cost savings and improved filtration performance.

Implementation Method 1

heating the mixture in a mould

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

heating said mould to a temperature in the range of 150 to 350 °C

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 3

Activated Carbon is useful for the purification of drinking water as it aids in the removal of chemical contaminants

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 4

To prevent and/or reduce the occurrence of bacterial colonization on the surface of the Carbon block, such blocks are generally impregnated with a metal such as Silver, Copper or Zinc

Methodology Applied
Scientific EffectAntimicrobial effect:

Data Source

PatentEP2177252B2Carbon block filter
Publication Date: 2014.05.14 UNILEVER NV

AI summary

The present invention relates to a process for making metal impregnated bound Carbon block filters. In particular the present invention to a process for preparing a moulded Carbon block filter impregnated with a metal selected from Silver, Copper or Zinc, with relatively low level of variation in metal content across the blocks, relatively lower deviation from the theoretical metal content, and where the leach-rate of metal from the block during use is relatively low.