Recess Plate Drying Gas Discharge for Filter Capacity

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Solution Overview

Problem

Press filter devices face reduced filtration capacity and erosion issues due to the need for larger pipes or increased gas flow speeds when expanding drying gas, and they often lack effective drying of the filter cake.

Innovation Solution

The method involves piping drying gas directly from the filter chamber to the ambiance, eliminating the need for expanded gas collecting ducts, and using movable membranes to press remaining liquid from the filter cake, allowing for increased filtration capacity and efficient drying without erosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If larger pipes are used to pipe expanded drying gas from filter chamber back to head piece, then drying gas can be transported, but pipe cross section becomes unavailable for filter chamber thus decreasing filtration capacity

Engineering Contradiction:
Improvedrying gas transportVSAvoidfiltration capacity
Core Design Contradiction:
SpeedVSProductivity

Solution Approach 1:

The patent extracts the harmful function of collecting and returning expanded drying gas from the system. Instead of routing the expanded drying gas back through collecting ducts, the invention discharges it directly to the environment through dedicated outlets in the recess plates, thereby eliminating the need for large return pipes that would reduce filtration chamber space and productivity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the gas flow paths by providing separate outlets for drying gas discharge in the recess plates, distinct from the filtrate collecting ducts. This segmentation allows independent optimization of each flow path - drying gas exits locally without requiring long return passages, while filtrate collecting ducts maintain their original function for liquid removal.

Inventive Principle:
Principle #1Segmentation

2Speed

If increased speed of gas flow is used to pipe expanded drying gas back to head piece, then drying gas can be transported, but erosion and wearing of recess plate occurs

Engineering Contradiction:
Improvedrying gas flow speedVSAvoidrecess plate durability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent removes the problematic high-speed gas flow through the recess plate by providing direct discharge outlets. The drying gas exits at low speed through outlets positioned in the recess plates themselves, eliminating the high-velocity flow path that would cause erosion and wear on the plate material.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If filtrate collecting ducts are used for both pressurized drying gas and expanded drying gas, then system structure is maintained, but pipe cross section is insufficient for both functions

Engineering Contradiction:
Improveduct system structureVSAvoidfiltration capacity
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent extracts the expanded drying gas flow from the filtrate collecting duct system and provides it with separate discharge outlets in the recess plates. This eliminates the conflict between the two gas flow functions and allows the filtrate collecting ducts to be optimized solely for liquid filtrate removal, maximizing their cross-sectional availability for that purpose.

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach enhances filtration capacity by repurposing pipe cross-sections and prevents erosion, while ensuring effective drying of the filter cake, thus improving the overall efficiency and durability of the filter device.

Implementation Method 1

After permeating the cake, the drying gas pressure falls down to ambient pressure and the drying gas expands, accordingly

Methodology Applied
Scientific EffectGas expansion: Boyle's Law

Data Source

PatentEP2838638B1Method for filtering a suspension and recess plate
Publication Date: 2018.03.14 OUTOTEC FINDLAND OY
  • EP2838638B1 patent drawingFigure 1a~1b
  • EP2838638B1 patent drawingFigure 1c
  • EP2838638B1 patent drawingFigure 2a~2c

AI summary

The invention relates to a method for filtering a suspension in a filter device, the filter device having between a stationary head piece and a movable end piece a pack of at least a first recess plate (1) having a first recess (4) and/or a second recess plate (1) having a second recess, the first recess (4) and/or the second recess forming a filter chamber between the first recess plate (1) and the second recess plate (1), and the filter device having two filter cloths between the first recess plate (1) and the second recess plate (1) for filtering a solid content out of the suspension as a filter cake, and the first recess plate (1) having a first duct (9) towards a first outlet (10) and the second recess plate (1) having a second duct towards a second outlet, the method comprising a sequence of steps, including piping the suspension into the filter chamber between the filter cloths, directing the suspension through the filter cloths, such that the filter cake settles between the filter cloths, discharging a liquid fraction of the suspension through the first duct (9) and the second duct out of the filter chamber and through the first outlet (10) of the first recess plate (1) and the second outlet of the second recess plate (1) as a filtrate, and piping a drying gas from the head piece into the filter chamber through the first duct (9) and discharging the same through the second duct. The invention further relates to such a recess plate (1). In order to increase filtration capacity of the known methods, recess plates (1) and filter devices, according to the invention it is suggested to discharge the drying gas straight from the second duct to the ambience. Further according to the invention it is suggested that a valve (14) for opening the first duct (9) to ambient air is nested in the recess plate (1).