Force-Feeding Screw and Plug Screw Feeder for Non-Wood Plant Material

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Solution Overview

Problem

Existing feeding arrangements for non-wood plant material, such as those using plug screw feeders, are inadequate for materials with lower bulk density, leading to inefficiencies and increased risks of backflow when handling pressurized materials, as they do not effectively increase the bulk density or manage the feeding process for non-wood plant materials in treatment vessels.

Innovation Solution

A feeding arrangement comprising a force-feeding screw and a plug screw feeder, where the distance between the force-feeding screw and the plug screw is optimized, and the rotational speeds are adjusted to ensure efficient compression and minimize backflow, allowing for higher bulk density and effective feeding of non-wood plant materials, even under pressurized conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a plug screw feeder is used for feeding non-wood plant material, then the material can be transported to the treatment vessel, but the bulk density of the material is not sufficiently increased leading to inefficiencies and backflow risks

Engineering Contradiction:
Improvebulk densityVSAvoidbackflow risk
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The feeding system is divided into two separate screws: a first screw for feeding the material and a second screw for compression. This segmentation allows each screw to perform its specific function optimally - the first screw introduces material while the second screw provides compression, together achieving sufficient bulk density increase and eliminating backflow risks

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first screw acts as an intermediary device between the material source and the compression mechanism. It feeds material to the second screw in a controlled manner, enabling the compression process to work on properly positioned material and achieve effective density increase without causing backflow

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If the plug screw feeder is used with constant inner diameter, then the structure is simple, but the compression is essentially axial and does not sufficiently increase bulk density

Engineering Contradiction:
Improvebulk densityVSAvoidfeeder structure
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The feeding system is divided into two separate screws: a first screw for feeding the material and a second screw for compression. This segmentation allows each screw to perform its specific function optimally - the first screw introduces material while the second screw provides compression, together achieving sufficient bulk density increase and eliminating backflow risks

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second screw is positioned with its end closer to the discharge end of the first screw, creating a localized compression zone. This local arrangement allows compression to occur at the critical point where material enters the treatment vessel, maximizing density increase without requiring complex structures throughout the entire feeder

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If force-feeding is applied to increase packing density, then the inlet section volume is filled uniformly, but the apparatus is not applicable to non-wood plant material without modification

Engineering Contradiction:
Improvebulk densityVSAvoidmaterial compatibility
Core Design Contradiction:
Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The feeding system is divided into two separate screws: a first screw for feeding the material and a second screw for compression. This segmentation allows each screw to perform its specific function optimally - the first screw introduces material while the second screw provides compression, together achieving sufficient bulk density increase and eliminating backflow risks

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the operational parameters by introducing a second compression screw that operates independently from the first feeding screw. This parameter change enables the system to handle non-wood plant material with lower bulk density by providing an additional compression stage, making the apparatus adaptable to different material types

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the distance between the first screw and second screw is large, then the structure is simple, but the material is not efficiently fed forward and compressed

Engineering Contradiction:
Improvefeeding efficiencyVSAvoidscrew arrangement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The second screw is positioned with its end closer to the discharge end of the first screw, creating a localized compression zone. This local arrangement allows compression to occur at the critical point where material enters the treatment vessel, maximizing density increase without requiring complex structures throughout the entire feeder

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The close positioning of the two screws ensures continuous action - material is fed forward by the first screw and immediately compressed by the second screw in a continuous process. This eliminates gaps or dead zones where material might stagnate, maintaining high feeding efficiency and proper compression throughout the material stream

Inventive Principle:
Principle #20Continuity of useful action

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 solution increases the bulk density of non-wood plant materials, creating a gas- and fluid-tight plug that minimizes backflow and enables feeding against higher pressures, enhancing the capacity and efficiency of treatment systems while ensuring even distribution of liquids during the impregnation process.

Implementation Method 1

the screw and associated screw pipe or housing also exercises a volumetric compression function

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

Plug screw feeders, in which a rotating screw transports the material forward

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP2817449B1Arrangement, system and method for handling non-wood plant material
Publication Date: 2016.11.16 VALMET AB
  • EP2817449B1 patent drawingFigure 1~2
  • EP2817449B1 patent drawing

AI summary

A feeding arrangement (100) for feeding non-wood plant material having a bulk density of 40-90 kg/m3 to a treatment vessel (200), the feeding arrangement comprising a plug screw feeder (40) for feeding the plant material to the treatment vessel, the feeder comprising a plug screw (10) and a corresponding plug screw housing (11) surrounding the plug screw (10), a force–feeding screw (20) for feeding incoming material to the plug screw and a corresponding force-feeding screw housing (21) surrounding the force-feeding screw (20), the force-feeding screw being arranged to provide the material to an inlet section(12) of the plug screw (10), a feeding device (50) being arranged to feed incoming material to the force-feeding screw, and where the distance (D) between an outermost point of a last screw thread (23) of the force-feeding screw (20) to a point on the outer diameter of the plug screw (10) at the inlet section (12) is 0-90 mm. A system (1000) and a method for treatment of non-wood plant material comprising such a feeding arrangement (100).