Split Mold Pulp Tray Pressing with Vacuum Dewatering

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Solution Overview

Problem

The high energy consumption and production costs, as well as extended production time, associated with molding fibrous pulp into tray-shaped articles, limit their popularity as an environmentally friendly alternative to plastic containers.

Innovation Solution

A system utilizing a split mold with a heating device and compressors to establish elevated fluid pressure, allowing for simultaneous heating and dewatering of the pulp within the mold, reducing the need for a separate drying step and optimizing material usage and strength of the final product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional separate drying station processing is used, then complete drying is achieved, but production time is extended and energy consumption increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidproduction time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The invention merges the drying function into the molding press by equipping it with heating elements and vacuum capability, eliminating the need for a separate drying station. The press simultaneously performs molding and drying operations, reducing both production time and energy consumption while maintaining complete drying effectiveness.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The molding press is transformed into a multi-functional device that combines molding, heating, and vacuum drying capabilities. This universal device performs multiple operations that traditionally required separate equipment, thereby reducing production time and energy consumption.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Loss of substance

If traditional molding processes are used, then adequate strength is achieved, but material usage is high

Engineering Contradiction:
Improvematerial usageVSAvoidstrength of molded article
Core Design Contradiction:
Loss of substanceVSStrength

Solution Approach 1:

The invention changes the physical parameters during molding by applying vacuum to remove excess water and using controlled heating to optimize fiber bonding. This allows reduction of material usage while maintaining adequate strength through improved densification and bonding rather than simply adding more material.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If high energy consumption processes are used, then complete dewatering is achieved, but production costs increase

Engineering Contradiction:
Improveproduction costVSAvoidenergy consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The invention uses vacuum (pneumatic principle) to facilitate dewatering during the molding process. By creating negative pressure, water is removed more efficiently with less energy input compared to traditional high-energy dewatering methods, thereby reducing production costs while achieving complete dewatering.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 significantly reduces energy consumption and production time while enhancing the strength and reducing material usage in molded pulp articles, making them a more viable alternative to plastic containers.

Implementation Method 1

a heating device, said heating device being configured for heating said male mold part

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a first compressor configured for establishing a temporary elevated fluid pressure of more than 1 bar in said one or more further cavities

Methodology Applied
Scientific EffectPressure increase: Pressure Increase

Implementation Method 3

said first surface allowing fluid to flow between said first cavity and said one or more further cavities

Methodology Applied
Scientific EffectDarcy's law: Pressure Gradient

Data Source

PatentEP3204555B1A system and a method for producing a molded article, such as a tray
Publication Date: 2018.08.15 ECOXPAC
  • EP3204555B1 patent drawingFigure 1a~1b
  • EP3204555B1 patent drawingFigure 2a~2b
  • EP3204555B1 patent drawingFigure 3a~3b

AI summary

The invention concerns a system for producing a molded article from pulp and including a split mold (11) with a female mold part (12), a pressing tool (25) having a male mold part (13), and a first cavity (21) for the pulp between the female mold part and the male mold part, a heating device (30), the heating device being configured for heating the male mold part, the female mold part comprising one or more further cavities (24) and a first surface (23') facing the interior of the first cavity and being for a layer (7) of the pulp, the first surface allowing fluid contained in the pulp to flow into said one or more further cavities, a first compressor (16) configured for establishing a temporary elevated fluid pressure of more than 1 bar in the one or more further cavities. In an embodiment, the male mold part is expandable and comprises an expanding device (17) configured for expanding the expandable male part by establishing an inside pressure in a hollow (H) of the pressing tool. The invention also relates to a method for producing a molded article, using the aforementioned inventive system.