Ascending Convective Air Flow for Uniform Food Drying

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Solution Overview

Problem

Existing drying methods for fruits and vegetables often result in negative effects on the product's color and consistency due to high temperatures, leading to a loss of organoleptic qualities, and pose hygiene challenges with uneven exposure and the need for continuous cleaning.

Innovation Solution

A drying plant and method using ascending insufflation of hot air with low temperatures and low humidity, featuring a circular drying chamber design with tangentially introduced air flows that converge to create a convective, ascending air flow, combined with heat recovery and self-cleaning capabilities to ensure uniform treatment and preservation of organoleptic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high temperatures are used for drying, then drying speed is improved, but organoleptic qualities deteriorate

Engineering Contradiction:
Improvedrying speedVSAvoiddamage to organoleptic qualities
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the temperature parameter from high to low (below 100°C, preferably 20-80°C) and modifies the air flow parameters (ascending direction, specific velocity ranges) to achieve effective drying at lower temperatures that preserve organoleptic qualities

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention inverts the conventional downward air flow direction to an ascending direction, where air enters from below and moves upward through the product layers, fundamentally changing the heat and mass transfer dynamics to enable gentle low-temperature drying

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

2Productivity

If conventional drying methods are used, then drying efficiency is improved, but uniformity of treatment deteriorates

Engineering Contradiction:
Improvedrying efficiencyVSAvoiduniformity of product surface treatment
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention inverts the air flow direction from conventional downward to upward ascending flow, which naturally promotes more uniform distribution across product layers and improves surface treatment consistency while maintaining drying efficiency

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

Solution Approach 2:

The invention introduces air flow from a horizontal dimension (below the product layers) moving vertically upward, adding a new dimensional approach to heat and mass transfer that enhances uniformity across the product surface

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

3Productivity

If high temperatures are used for drying, then moisture elimination is improved, but energy consumption increases

Engineering Contradiction:
Improvemoisture elimination rateVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The invention changes the temperature parameter from high to low (below 100°C) while adjusting air flow parameters (velocity, direction) to compensate, achieving effective moisture elimination at lower energy input

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs continuous circulation of air through the product layers with controlled ascending flow, maintaining continuous moisture removal at lower temperatures to reduce overall energy consumption compared to intermittent high-temperature drying

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 achieves uniform drying with minimal product stress, preserving the organoleptic qualities of fruits and vegetables while allowing for automatic self-cleaning, reducing energy consumption, and optimizing air flow to maintain a laminar state, thus enhancing the quality and efficiency of the drying process.

Implementation Method 1

the flow of air which, transversely introduced from above, preferably tangentially, inside the drying chamber with a substantially circular cross section, first moves by circulatory motion, to then, once the bottom of the drying chamber is reached, cross the belts supporting the product from the bottom upwards in an ascending and convective manner

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

Each cycle comprises a water evaporation step

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3755154B1Plant and method for drying foodstuffs
Publication Date: 2022.03.30 TECNOFRUTTA
  • EP3755154B1 patent drawingFigure 1
  • EP3755154B1 patent drawingFigure 2
  • EP3755154B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a plant and a method for drying foodstuffs, in particular, fruit and vegetables, wherein such products are subjected to cyclic water evaporation steps, by means of ascending insufflation of hot and dry air, making sure that the treatment occurs uniformly over the entire product surface. The temperature, the humidity degree and the air flow rate are controlled so as to have specific values for each step of the drying process. The drying products are affected by hot air in forced movement, with an ascending transverse flow.