Filter Press Backflushing for Continuous Pellet Production

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Solution Overview

Problem

Chamber filter presses experience rapid decline in filtration efficiency due to the formation of an impermeable layer on the filter fabric, necessitating frequent cleaning and limiting continuous operation, while rotary filter screens do not allow for further processing of the retentate.

Innovation Solution

A method involving the introduction of a particle-laden liquid into a filter chamber, application of pre-pressure to retain retentate and permeate, backflushing permeate to detach retentate particles, and pressing the filter cake into pellets, enabling continuous operation without fabric cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high filter pressure is applied to increase filtration capacity, then filtration capacity is improved initially, but an impermeable layer forms quickly on the filter fabric causing filtration to stop

Engineering Contradiction:
Improvefiltration capacityVSAvoidcontinuous operation capability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The filter press operates in periodic cycles: filtration phase where particles are retained on the filter fabric, followed by a backflushing phase where permeate is reversed through the fabric to remove the compacted layer. This periodic reversal prevents permanent clogging and enables continuous operation without stopping for cleaning.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The backflushing process recovers the filtration capacity of the filter fabric by removing the impermeable layer. Instead of discarding the filter fabric after clogging, the system regenerates it in-place, allowing repeated use without manual cleaning or replacement.

Inventive Principle:
Principle #34Discarding and recovering

2Quantity of substance

If chamber filter press is used for particle separation, then particles can be concentrated into retentate, but the filter fabric becomes clogged requiring laborious cleaning and emptying

Engineering Contradiction:
Improveparticle concentration in retentateVSAvoidcleaning and maintenance effort
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The filter press performs its own cleaning through the backflushing mechanism. The system uses its own permeate flow in reverse to automatically remove the compacted particle layer from the filter fabric, eliminating the need for external manual cleaning operations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The backflushing operation reverses the normal filtration flow direction. Instead of forcing liquid through the filter fabric from one side, the permeate is pushed back through the fabric in the opposite direction, effectively stripping away the compacted particle layer that formed during filtration.

Inventive Principle:
Principle #13The other way round (Inversion)

3Duration of action of stationary object

If rotary filter screen device is used for continuous operation, then cleaning is not required, but further processing of retentate for pellet production is not possible

Engineering Contradiction:
Improvecontinuous operation timeVSAvoidretentate processing capability
Core Design Contradiction:
Duration of action of stationary objectVSAdaptability or versatility

Solution Approach 1:

The filter press combines multiple functions in one device: it performs continuous particle separation like a rotary screen, concentrates particles into removable filter cakes, and enables further processing of the retentate into pellets. The filter cakes can be easily removed and processed downstream into various pellet products.

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

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

Restores filter fabric drainage capacity, allows for continuous pellet production with increased particle concentration, and eliminates the need for laborious cleaning, maintaining high filtration efficiency.

Implementation Method 1

a retentate from the particle-laden liquid to be retained by a filter fabric in the filter chamber and a permeate to be directed to a drain

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

Releasing the pre-pressure on the filter chamber and backflushing at least part of the permeate from the drain into the filter chamber

Methodology Applied
Scientific EffectBackflushing:

Implementation Method 3

Pressing the filter cake into a pellet by applying a main pressure to the filter chamber

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4426458B1Method and filter press for producing pellets from a particle-laden liquid, and plant for producing pellets
Publication Date: 2025.12.17 INNOVATIVE TECH GBR
  • EP4426458B1 patent drawingFigure 1
  • EP4426458B1 patent drawingFigure 2a~2c
  • EP4426458B1 patent drawingFigure 2d~2e

AI summary

The invention relates to a method for producing pellets (16) in a filter press (1) from a particle-laden liquid (10), said method comprising the following steps: A) introducing the particle-laden liquid (10) via a feed line (6) into a filter chamber (3); B) applying a pre-pressure to the filter chamber (3), as a result of which a retentate (7) from the particle-laden liquid (10) is retained on a filter fabric (8) in the filter chamber (3) and a permeate (11) is fed to a discharge line (5); C) releasing the pre-pressure on the filter chamber (3) and back-flushing at least part of the permeate (11) from the discharge line (5) into the filter chamber (3); D) repeating steps A) to C) until a filter cake is obtained from the retentate (7) in the filter chamber (3); E) pressing the filter cake to produce a pellet (16) by applying a main pressure to the filter chamber (3) and removing the pellet (16) from the filter chamber (3). The invention also relates to a filter press (1) and to a plant for producing pellets (16).