Concave-Convex Nozzle Plate for Strand Granulation

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Solution Overview

Problem

Conventional nozzle plates in extrusion systems suffer from inhomogeneous pressure distribution, leading to uneven strand exit speeds and increased risk of strand breaks, limiting throughput and process reliability, and existing solutions either require significant equipment changes or introduce material losses and adhesion issues.

Innovation Solution

A concave-convex nozzle plate design with nozzles arranged on a circular arc segment, allowing for increased nozzle spacing or number, resulting in more uniform pressure distribution and reduced deflection angles, enhancing throughput and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of nozzles is increased to maximize throughput, then productivity increases, but the distance between strands decreases leading to increased strand breaks and reduced reliability

Engineering Contradiction:
ImprovethroughputVSAvoidstrand breakage risk
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The nozzle plate is designed with a convex curvature instead of a flat surface. The nozzles are arranged on the convex side of the curved nozzle plate, which causes the extruded strands to diverge naturally. This curvature geometry allows for increased nozzle density while maintaining adequate spacing between adjacent strands, thereby increasing throughput without proportionally increasing strand breakage risk.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention transitions from a two-dimensional flat nozzle plate to a three-dimensional curved surface. By utilizing the additional spatial dimension provided by the convex curvature, more nozzles can be packed into the available area while the natural divergence of strands in the radial direction maintains safe inter-strand distances, resolving the contradiction between nozzle density and strand spacing.

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

2Productivity

If take-off speed is increased to maximize space utilization, then productivity increases, but running behavior deteriorates and process reliability decreases

Engineering Contradiction:
ImprovethroughputVSAvoidprocess reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The convex curved nozzle plate creates a natural divergence pattern for the extruded strands. This geometric arrangement allows the strands to be deposited more evenly spaced on the collection surface, enabling higher take-off speeds without the strands tangling or running unsteadily, thus maintaining process reliability at higher productivity levels.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Device complexity

If nozzles are arranged in a conventional planar configuration, then device complexity is low, but pressure distribution is inhomogeneous leading to uneven exit speeds

Engineering Contradiction:
Improvenozzle plate structureVSAvoidstrand exit speed uniformity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The convex curved nozzle plate geometry naturally promotes more uniform pressure distribution across the nozzle array compared to a flat plate. The curvature allows pressure to equalize more effectively across the melt distribution channels, resulting in more uniform exit speeds from all nozzles. This geometric solution achieves improved precision without significantly increasing device complexity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2424721B1Nozzle plate having nozzles disposed convexly and the use of the same
Publication Date: 2016.01.06 AKRO PLASTIC
  • EP2424721B1 patent drawingFigure 1~2
  • EP2424721B1 patent drawingFigure 3~4
  • EP2424721B1 patent drawingFigure 5

AI summary

The invention relates to a concave-convex nozzle plate (4) having an arrangement of the nozzles (3) on the convex side. Said nozzle plate and an extrusion device (2) equipped therewith is suitable for extruding plastic melts in strand granulation.