Hood Dishwasher Drying Circuit With Top Suction Recirculation

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Solution Overview

Problem

Hood-type industrial dishwashers face inefficiencies in drying due to air discharge systems, which lead to environmental vapor issues, rapid cooling of dishes, and poor drying effectiveness, especially in short wash cycles, as well as limitations in air recirculation circuits that fail to effectively manage hot and humid air.

Innovation Solution

An air recirculation drying circuit is implemented with a suction duct at the top of the hood, connected to a condensation duct with a fan and condenser, ensuring efficient air recirculation and uniform airflow across the wash chamber, preventing sudden temperature drops and exploiting the drying phase for sanitization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If air discharge drying system is used in hood-type dishwasher, then drying process is simplified, but rapid cooling of dishes occurs and environmental vapor emission increases

Engineering Contradiction:
Improvedrying circuit complexityVSAvoiddish temperature
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

A recirculation duct acts as an intermediary channel, capturing hot humid air at the top of the hood and redirecting it through a condenser unit before reintroducing it at the bottom. This intermediary mechanism prevents direct discharge to environment while avoiding sudden cooling of dishes, maintaining temperature through controlled thermal management.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of discarding hot humid air directly to environment, the system recovers this thermal energy by routing it through a condenser that extracts moisture while preserving heat. The recovered warm air is then reintroduced at the bottom, maintaining dish temperature and reducing environmental vapor emission.

Inventive Principle:
Principle #34Discarding and recovering

2Device complexity

If air recirculation circuit is applied to stationary lower half only, then circuit structure is simplified, but drying effectiveness decreases due to hot humid air rising

Engineering Contradiction:
Improvecircuit structureVSAvoiddrying effectiveness
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The recirculation circuit is segmented into distinct functional zones: a suction duct positioned at the top of the mobile hood to capture hot humid air, a condenser unit for moisture removal, and a reintroduction duct at the bottom of the stationary lower half. This segmentation allows each component to perform its function optimally while managing the natural convection of hot air.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of introducing air at the top and extracting at the bottom (conventional approach), the system inverts the flow pattern by suctioning at the top where hot humid air naturally accumulates and reintroducing at the bottom. This inversion aligns with natural convection currents, improving drying effectiveness without increasing complexity.

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

3Device complexity

If suction duct is positioned at bottom and reintroduction at top, then airflow path is simplified, but preferential paths occur and uniform drying is compromised

Engineering Contradiction:
Improveairflow pathVSAvoiduniformity of drying
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system inverts the conventional airflow arrangement by positioning the suction duct at the top of the hood and the reintroduction duct at the bottom. This inversion creates a vertical circulation pattern that prevents preferential horizontal paths, ensuring uniform airflow distribution across all dishes in the wash chamber.

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

Solution Approach 2:

The airflow path transitions from potential horizontal preferential paths to a vertical circulation pattern by suctioning at the top and reintroducing at the bottom. This dimensional change in airflow direction ensures more uniform distribution of air across the wash chamber, improving drying uniformity.

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

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 configuration enables effective and rapid dish drying without environmental vapor emission, maintaining dish temperature, and ensuring optimal drying of all dishes by efficiently removing hot and humid air, thus overcoming the limitations of air discharge systems and short wash cycles.

Implementation Method 1

a drying circuit (5) arranged at the back of the machine, said drying circuit comprising a suction duct (4) arranged at the top of the hood (1), a condensation duct (5) arranged at the back of the machine, a fan (6) and a condenser (7)

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

achieve through condensation a decrease in the humidity of the treated air so as to dry the dishes

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 3

a heating element arranged at the back of the machine, underneath the suction duct

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

the hottest and most humid portion of the air present within the wash chamber is efficiently sucked away

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2163181B1Hood-type industrial dishwasher with improved drying circuit
Publication Date: 2012.01.25 BONFERRARO SPA
  • EP2163181B1 patent drawingFigure 1
  • EP2163181B1 patent drawingFigure 2
  • EP2163181B1 patent drawingFigure 3

AI summary

In a hood-type industrial dishwasher with a wash chamber defined by a hood (1), a bottom tank (2) and a rear vertical wall (3) that makes part of the stationary lower part of the dishwasher, as well as with a drying circuit comprising a condensation duct (5) containing a fan (6) and a condenser (7), the drying circuit includes a suction duct (4) located at the top of said hood (1) and suitable to connect (B, C) with the condensation duct (5) when the hood (1) is closed. In this way, it is possible to perform an effective drying of the dishes even in a short time thanks to the fact that the hottest and most humid portion of the air present within the wash chamber is efficiently sucked away at the top of the hood (1) and there is achieved an almost uniform airflow across the whole wash chamber. Furthermore, since there is achieved an air recirculation drying without a sudden decrease in the temperature of the dishes due to the inflow of external air, it is possible to exploit also the drying phase for the sanification of the dishes.