Concave Air-Guide Member for Uniform Hot-Air Cooking

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Solution Overview

Problem

Existing air-guide members in air-based fryers often result in uneven cooking of food ingredients due to non-uniform air flow distribution, leading to undercooked or overcooked items, even with extended cooking times.

Innovation Solution

An air-guide member with symmetrically arranged air-deflecting arms having inclined surfaces forming a concave air channel, which redirects a portion of the input air flow towards the inner part, ensuring even air pressure distribution and minimizing air pressure loss, allowing for more uniform cooking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If known air-guide members direct hot air essentially upwards, then air flow is directed towards food ingredients, but cooking is not optimized due to non-uniform air pressure distribution causing uneven cooking

Engineering Contradiction:
Improvecooking uniformityVSAvoidair pressure distribution uniformity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The air-guide member is segmented into multiple air-deflecting arms (at least three) arranged symmetrically around a central axis. Each arm includes inclined surfaces that divide and redirect air flow in specific directions, creating multiple concave air channels that distribute hot air uniformly across the food preparation chamber.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the air-guide member have different geometric configurations. The air-deflecting arms have specific incline angles (first incline surface at angle α, second incline surface at angle β) that are optimized for their local position. The concave air channels have varying cross-sectional areas along their length, with the minimum cross-sectional area positioned at specific locations to control air flow velocity and pressure distribution locally.

Inventive Principle:
Principle #3Local quality

Solution Approach 3:

The air-deflecting arms feature curved surfaces including concave air channels with rounded profiles. The inclined surfaces are designed with specific curvature radii (R1 for the first incline surface, R2 for the second incline surface) to smoothly redirect air flow while maintaining uniform pressure distribution and preventing dead zones.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If cooking duration is increased to ensure under-cooked items are fully cooked, then all food ingredients reach minimum cooking requirements, but some food ingredients become over-cooked

Engineering Contradiction:
Improveminimum cooking requirement fulfillmentVSAvoidcooking time efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The symmetric arrangement of air-deflecting arms creates a self-regulating air flow pattern where hot air is distributed uniformly to all food ingredients simultaneously. The concave air channels naturally guide air flow to maintain consistent velocity and pressure across different zones, providing inherent feedback control that prevents localized over-cooking while ensuring all items reach minimum cooking requirements.

Inventive Principle:
Principle #23Feedback

3Productivity

If air flow velocity is increased to improve cooking speed, then cooking time is reduced, but air pressure loss increases and cooking uniformity deteriorates

Engineering Contradiction:
Improvecooking speedVSAvoidair pressure loss
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The concave air channels feature curved profiles with optimized radius of curvature that guide air flow smoothly around bends without creating sharp eddies or turbulence. This reduces energy loss from flow separation and maintains higher effective air velocity for cooking while minimizing pressure drop across the air-guide member.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The air channel cross-sectional area varies along the flow direction, with the minimum cross-sectional area positioned at specific locations within the concave channels. This geometric parameter variation accelerates air flow at critical points to maintain cooking effectiveness while managing overall pressure loss through the system.

Inventive Principle:
Principle #35Parameter changes

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 even cooking of food ingredients by ensuring a uniform air flow distribution, reducing cooking inconsistencies and allowing for effective fat residue collection within the air-guide member.

Implementation Method 1

the concave air channel allows directing a portion of the input air flow towards the inner part of the air-guide member

Methodology Applied
Scientific EffectFluid flow redirection through concave geometry:

Implementation Method 2

each of the first surface receives an air flow component along its length that can be further redirected upwards thanks to the inclination of this first surface

Methodology Applied
Scientific EffectAir flow redirection through inclined surface:

Implementation Method 3

The food ingredients can thus receive a flow of hot air having a more uniform air pressure distribution, which results in a more even cooking of the food ingredients

Methodology Applied
Scientific EffectConvection heat transfer: Convection

Data Source

PatentEP3162259B1Air-guide member for an apparatus using air flow to prepare food ingredients
Publication Date: 2018.10.24 KONINKLIJKE PHILIPS NV
  • EP3162259B1 patent drawingFigure 1
  • EP3162259B1 patent drawingFigure 2A
  • EP3162259B1 patent drawingFigure 2B

AI summary

The invention relates to an air-guide member (100) for guiding an air flow (AF) in the food preparation chamber of an apparatus using the air flow (AF) to prepare food ingredients. The air-guide member (100) comprises a plurality of air-deflecting arms (101) arranged symmetrically and extending in a horizontal plane (P) between an inner part (IP) and an outer part (OP) of the air-guide member (100). The air-deflecting arms (101) comprises a first surface (S1) being inclined with a positive angle compared to the horizontal plane (P), and a second surface (S2) being inclined with a negative angle compared to the horizontal plane (P). The air-deflecting arms (101) is such that the second surface (S2) of a given air-deflecting arms (101) and the first surface (S1) of an air-deflecting arms (101) consecutive to the given air-deflecting arms (101) intersect to form a concave air channel (AC) extending between the outer part (OP) and the inner part (IP). This allows directing the air flow upwards and more evenly between the outer part and the inner part of the air-guide. The food ingredients can thus receive a flow of hot air having a more uniform air pressure distribution, which results in a more even cooking of the food ingredients.