Self-cleaning food cooking oven

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Solution Overview

Problem

Existing self-cleaning oven systems struggle to precisely control the temperature profile of washing detergents during cleaning cycles, leading to suboptimal cleaning performance due to thermal inertia and temperature oscillations.

Innovation Solution

The oven system includes a control unit that selectively activates liquid heating elements and a liquid supply arrangement to heat the washing detergent to the activation temperature, allowing it to be sprayed onto heating elements before reaching the walls, ensuring precise temperature control and efficient cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the washing detergent is preheated at the reservoir by means of a heating device, then the washing detergent can be sprayed at the desired activation temperature, but the temperature cannot be rapidly varied or decreased due to thermal inertia

Engineering Contradiction:
Improvewashing detergent temperatureVSAvoidtemperature profile control
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The heating function is segmented from the reservoir to the spray path. Instead of heating the detergent in the reservoir, the system uses pre-existing heating elements (cooking chamber heating elements or dedicated nozzle heating elements) located along the spray path to heat the detergent locally as it is being sprayed, enabling rapid temperature adjustment without thermal inertia constraints.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces heating elements as intermediaries between the detergent reservoir and the cooking chamber walls. These heating elements (either the cooking chamber heating elements or dedicated nozzle heating elements) act as mediators to transfer thermal energy to the detergent during the spraying process, enabling precise temperature control at the point of application.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the washing detergent is left at room temperature in the reservoir, then thermal inertia is avoided, but the activation temperature cannot be controlled precisely due to temperature oscillations in the thermo-regulated cooking chamber

Engineering Contradiction:
Improvetemperature profile controlVSAvoidactivation temperature control
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system applies local heating at the spray path or nozzle area rather than heating the entire cooking chamber. This localized heating approach allows precise temperature control of the detergent without being affected by the temperature oscillations that occur in the larger cooking chamber environment, enabling accurate activation temperature maintenance.

Inventive Principle:
Principle #3Local quality

3Temperature

If the cooking chamber is thermo-regulated to heat the walls for warming the washing detergent, then the detergent reaches activation temperature, but precise temperature control is impossible due to temperature oscillations

Engineering Contradiction:
Improvewashing detergent temperatureVSAvoidactivation temperature control
Core Design Contradiction:
TemperatureVSMeasurement precision

Solution Approach 1:

The system performs preliminary heating of the spray path or nozzle area before detergent spraying begins. By pre-heating the local area where the detergent will be applied, the system ensures the detergent reaches the correct activation temperature immediately upon contact, without being subject to the temperature oscillations of the overall cooking chamber thermo-regulation system.

Inventive Principle:
Principle #10Preliminary 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

This approach enables precise temperature control of the washing detergent, improving cleaning performance by maintaining the detergent at the optimal activation temperature during spraying, even for temperature-sensitive detergents like enzymatic ones, and allows for efficient reuse of the detergent through recirculation.

Implementation Method 1

at least one liquid heating element configured to heat the washing detergent supplied by the liquid supply arrangement

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

when the washing detergent at room temperature is sprayed onto the walls, its temperature increases by exchanging heat with the walls

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2708819B1Self-cleaning food cooking oven
Publication Date: 2017.06.14 ELECTROLUX PROFESSIONAL SPA
  • EP2708819B1 patent drawingFigure 1
  • EP2708819B1 patent drawingFigure 2
  • EP2708819B1 patent drawingFigure 3~4

AI summary

An oven (100) is provided. The oven (100) comprises a cooking chamber (105) for housing food to be cooked, a control unit (135) , and a reservoir (220) for containing a washing detergent (225) at room temperature. The washing detergent (225) has a corresponding activation temperature. The oven (100) further comprises a liquid supply arrangement (202) configured to be selectively activated by the control unit (135) for supplying the washing detergent (225) into the cooking chamber (105) , and at least one liquid heating element (125 ; 270) configured to heat the washing detergent supplied by the liquid supply arrangement (202) and to be selectively activated by the control unit (135). During a washing cycle (300) of the cooking chamber, the control unit (135) is configured to perform the following ordered sequence of operations: a) activate the at least one liquid heating element (125; 270) for a first time period sufficient to increase its temperature at least to the activation temperature; b) deactivate the at least one liquid heating element (125; 270); c)when the temperature of the at least one liquid heating element (125; 270) is about the activation temperature, activate the liquid supply arrangement (202) so that the washing detergent (225) is heated by the at least one liquid heating element (125; 270) while supplied into the cooking chamber (105).