Profiled Screw Conveyor Lining for Material Retention

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Solution Overview

Problem

Existing worm housing linings in screw conveyors and presses face issues with reduced conveying capacity due to material falling over the outer edge of worm threads, especially in open-top troughs, and require frequent and costly maintenance of individual strips.

Innovation Solution

A mat-like lining with radial profiling, featuring longitudinal ribs and depressions, which can be bent at room temperature to form a U-shaped or ring-shaped cross-section, allowing for easy adaptation and maintenance, and includes notches for deformation to enhance material interlocking and conveying capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual plastic strips are mounted in the longitudinal direction of the housing, then the housing wear is prevented and the exit area remains free, but the maintenance cost and effort increase due to frequent replacement of multiple components

Engineering Contradiction:
Improvehousing wear preventionVSAvoidmaintenance effort
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

Multiple individual plastic strips are merged into a single mat-like lining component. This mat is divided into multiple wear portions along its length, allowing replacement of the entire lining as one piece rather than multiple separate strips, thereby reducing maintenance effort while maintaining housing protection functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The mat-like lining is segmented into multiple wear portions along its longitudinal direction. Each wear portion corresponds to a specific section of the housing and can be replaced independently by cutting or removing only the affected section, combining the benefits of single-component installation with localized replacement capability

Inventive Principle:
Principle #1Segmentation

2Duration of action of stationary object

If a slippery plastic lining shell is used, then the service life of the lining is extended, but the conveying capacity is reduced due to material falling over the outer edge of worm threads

Engineering Contradiction:
Improvelining service lifeVSAvoidconveying capacity
Core Design Contradiction:
Duration of action of stationary objectVSProductivity

Solution Approach 1:

The lining surface is given different local qualities through profiling: ribs provide structural support and material retention in regions where material would otherwise fall off, while depressions create receiving spaces that guide material back onto the screw threads. This localized structural variation maintains the slippery plastic's wear resistance while improving conveying capacity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lining surface is transformed from a flat two-dimensional surface to a three-dimensional profiled structure with ribs and depressions. This adds vertical dimensionality to the lining, creating depth variations that prevent material spillage while maintaining the overall slipperiness of the plastic material

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of repair

If a mat-like lining is bent into U-shaped or ring-shaped cross section, then the adaptation to worm housing is simplified and maintenance time is reduced, but the manufacturing precision may be compromised

Engineering Contradiction:
Improvemaintenance timeVSAvoiddimensional stability
Core Design Contradiction:
Ease of repairVSManufacturing precision

Solution Approach 1:

The mat-like lining is pre-formed with integrated notches during manufacturing that serve as bending lines. These pre-defined weakness lines guide the bending process into the correct U-shaped or ring-shaped configuration, ensuring consistent dimensional results while simplifying the installation and adaptation process

Inventive Principle:
Principle #10Preliminary 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 mat-like lining design improves conveying capacity by interlocking material outside the screw thread with material inside, reducing material loss and increasing efficiency while minimizing maintenance efforts and costs.

Implementation Method 1

a mat-like lining which can be bent at room temperature to form a U-shaped or ring-shaped cross-section

Methodology Applied
Scientific EffectRoom temperature deformation: Deformation

Implementation Method 2

Notches, which extend in the longitudinal direction of the lining, form weakening or bending lines, so that the lining can be deformed polygonally at room temperature with little effort

Methodology Applied
Scientific EffectStress concentration at notches: Fracture Mechanics

Implementation Method 3

the portions of material that are located in the receiving spaces outside the circumference of the screw can interlock with the portions of the material that are located radially further inwards, namely in the screw threads and are transported in the screw

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Force

Implementation Method 4

the material to be conveyed is guided against the step in accordance with the direction of rotation of the worm, which improves the entrainment effect that results between the material portions in the screw thread and the material portions in the depression

Methodology Applied
Scientific EffectEntrainment: Entrainment

Implementation Method 5

a slippery plastic, which has a U-shaped cross section and is used in a screw trough

Methodology Applied
Scientific EffectSlippery plastic surface: Friction

Data Source

PatentEP4134339A1Worm casing liner
Publication Date: 2023.02.15 WISSING JOHANNES
  • EP4134339A1 patent drawingFigure 1~2
  • EP4134339A1 patent drawingFigure 3
  • EP4134339A1 patent drawingFigure 4~5

AI summary

In a screw housing lining (1) intended to be arranged in a housing designed as a trough (6) or tube (9) for receiving a screw conveyor (7), wherein the lining consists of a low-friction material on its inner surface facing the screw conveyor (7) and is profiled in the circumferential direction such that the lining (1) has a lower sliding resistance in the longitudinal direction than in the circumferential direction, the invention proposes that the lining (1) has at least two ribs (2) extending in the longitudinal direction and connected to each other by a groove-shaped area in which the lining (1) has a longitudinally extending recess (3) in its inner surface, and that the lining (1) has longitudinally extending indentations (4) along which the lining (1) has a reduced wall thickness.that the lining (1) is deformable at room temperature into a U-shaped or substantially ring-shaped cross-section.