Combination Weigher Buffer Zone and Opposite Screw Feeders

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Solution Overview

Problem

Combination weighers face issues with larger food products blocking access to trenches, damaging products between screw feeders and walls, and reduced throughput due to size variations, which existing solutions attempt to address by widening trenches or changing screw orientations, but at the cost of machine size and efficiency.

Innovation Solution

A compact combination weigher design incorporating a buffer zone with an upwardly extending hill-like structure and oppositely oriented screw feeders to facilitate larger product access and prevent clamping, using softer materials for screw feeders with specific cross-sectional shapes to ensure optimal product orientation and interaction, and a method for monitoring and optimizing weight combinations in weighing hoppers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the width of trenches is widened to accommodate larger food products, then the throughput and adaptability are improved, but the overall size of the combination weigher increases

Engineering Contradiction:
Improveability to accommodate larger food productsVSAvoidoverall size of the combination weigher
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The screw feeders are designed to rotate in opposite directions to dynamically adjust the spacing between them, creating a variable gap that can accommodate different product sizes without requiring wider trenches. This dynamic adjustment allows the static trench structure to handle variable product dimensions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The orientation and rotation direction of screw feeders are changed as a parameter to solve the problem. By rotating adjacent screw feeders in opposite directions, the effective clearance between them increases, allowing larger products to pass through without enlarging the trench width

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If screw feeders are positioned close together to maintain compact size, then the machine size is reduced, but larger food products may be blocked or damaged between the screw feeders and trench walls

Engineering Contradiction:
Improvecompact size of the machineVSAvoidproduct clamping and damage
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

Instead of rotating all screw feeders in the same direction, adjacent screw feeders are rotated in opposite directions. This inversion of the conventional approach creates an outward-facing gap between screw feeders that prevents clamping and eliminates the harmful compression effect on products

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

Solution Approach 2:

The screw feeders are configured with asymmetric rotation directions - adjacent feeders rotate in opposite directions. This asymmetric configuration creates different clearance patterns that prevent product clamping while maintaining compact trench dimensions

Inventive Principle:
Principle #4Asymmetry

3Productivity

If the dispersion unit rotates faster to increase throughput, then the productivity is improved, but the precision of product distribution to specific weighing hoppers deteriorates

Engineering Contradiction:
Improvethroughput of the combination weigherVSAvoidprecision of product distribution
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system uses sensors to detect product characteristics and provides feedback to the control unit, which then adjusts the rotation speed and direction of specific screw feeders. This feedback mechanism allows the system to maintain precision in product distribution even at higher rotation speeds by dynamically compensating for variations

Inventive Principle:
Principle #23Feedback

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 design allows for increased throughput by accommodating larger products without enlarging the machine, preventing product damage, and ensuring efficient feeding and weighing processes, while maintaining a compact size and minimizing manual intervention.

Implementation Method 1

conveyance units that extend radially away from the dispersion units for receiving food items from the dispersion unit... screw feeders arranged therein for advancing food products received from the dispersion units and radially away and into the associated weighing hoppers

Methodology Applied
Scientific EffectScrew conveyor mechanism: Screw

Implementation Method 2

The weighing hoppers are operated by a control unit by repeatedly monitoring the weight in each of the weighing hopper for finding an optimal weight combination

Methodology Applied
Scientific EffectWeight monitoring:

Data Source

PatentEP3568674B1A combination weigher
Publication Date: 2023.03.01 MAREL HF
  • EP3568674B1 patent drawingFigure 1~3
  • EP3568674B1 patent drawingFigure 4~5
  • EP3568674B1 patent drawingFigure 6~7

AI summary

This invention relates to a combination weigher, including a dispersion unit adapted to radially disperse food products dropped in from above and onto the dispersion unit, a plurality of V-shaped like guide structures extending radially away from a center of the dispersion unit and arranged such that a narrower end of the V-shaped like guide structures face a center point of the dispersion unit, and where the V-shaped like guide structures are designed such that for every second V-shaped like guide structure the distance R1 from the narrower end of the V-shaped like guide structure to the center point of the dispersion unit is smaller than the distance R2 from the narrower end of the remaining V-shaped like guide structures to the center of the dispersion unit, and where the sides of adjacent V-shaped like guide structures define side walls of trenches, where the trenches comprise circular sector shape bottom portions, where the trenches comprise receiving ends where the radially disperse food products are received from the dispersion unit and outfeed ends where the food products are released from the trenches, a plurality of hoppers associated to each of the trenches arranged below the outfeed ends of the trenches, a control unit, and screw feeders arranged in each of the trenches operated by the control unit, where the operation includes operate a rotational movement of the screw feeders and thus the conveying of the food products from the receiving ends of the trenches towards the outfeed ends of the trenches where they are released into the plurality of hoppers, wherein the space between adjacent V-shaped like guide structures at a distance R1 defines a buffer zone for radially dispersed food products from the dispersion unit, and where the screw feeders in the adjacent trenches thereof have opposite orientation and rotate in opposite directions such that upper part of the screw feeders are rotating away from each other.