Steam Escape Detection Control for Precision Cooking Appliances

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Solution Overview

Problem

Existing cooking appliances lack effective automatic control mechanisms to prevent overcooking and drying out of food, as they rely on temperature sensors to manage cooking processes without considering the timing and thermal properties of food.

Innovation Solution

The method utilizes the signal from a steam outlet sensor to control the cooking process by suppressing steam detection until a predetermined time, allowing for adjustments in heating power and target cooking chamber temperature, thereby preventing surface overcooking and charring, and using the time until steam emergence to determine subsequent cooking phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If steam detection is used to control cooking process, then cooking precision is improved, but false detection during warm-up phase causes control errors

Engineering Contradiction:
Improvecooking precisionVSAvoiddetection reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The control device suppresses steam detection signals during a predetermined warm-up phase before normal cooking begins. This preliminary suppression prevents false detection of steam generated during the warm-up process, ensuring that steam detection only occurs during the actual cooking phase when it is meaningful for controlling the cooking process.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If high heating power is used to reduce cooking time, then productivity is improved, but food surface dries out or chars

Engineering Contradiction:
Improvecooking speedVSAvoidsurface drying and charring
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The control device continuously monitors steam detection signals during cooking and dynamically adjusts heating power in response. When steam is detected indicating the food surface has reached cooking temperature, the system reduces heating power to prevent overheating, drying, or charring of the food surface while maintaining efficient cooking progress.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The heating power is made dynamically adjustable based on real-time steam detection feedback. The system transitions from high heating power during initial cooking to reduced heating power when steam detection indicates the food surface is sufficiently heated, allowing the cooking process to adapt to the actual state of the food.

Inventive Principle:
Principle #15Dynamics

3Reliability

If steam detection is suppressed during warm-up, then detection reliability is improved, but cooking time increases

Engineering Contradiction:
Improvedetection reliabilityVSAvoidcooking time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The warm-up phase is performed in advance with suppressed steam detection to prepare the cooking environment and food without interfering with future steam detection accuracy. This preliminary preparation ensures that when normal cooking begins, steam detection can accurately monitor the cooking process without being confounded by warm-up phase steam generation.

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 control of cooking phases, preventing overcooking and ensuring optimal cooking conditions by using the steam emergence time as a parameter to adjust heating power and temperature, resulting in better food quality.

Implementation Method 1

The steam outlet sensor comprises an opening in the cooking chamber and a temperature sensor arranged outside of the opening. If steam escapes from the food to be cooked, hot gas escapes through the opening, which can be measured by the temperature sensor.

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 2

The device has a conventional resistive heater with top heat 5a and bottom heat 5b used to heat the gases in the cooking chamber.

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

The device also has a steam generator 4, as described in EP 1 166 694, for example.

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2279682B1Preparation of food products by cooking with vapour escape detection
Publication Date: 2013.03.06 V-ZUG AG
  • EP2279682B1 patent drawingFigure 1~2
  • EP2279682B1 patent drawingFigure 3

AI summary

The method involves heating cooked food to temperature above 90 degrees Celsius in heating phases (A, B), such that steam is discharged from the food. The steam discharge is detected by a signal from a steam discharge-sensor. Heating power and/or a reference-cooking chamber temperature is reduced during detection of the steam discharge. Time duration (t1) from the beginning of the heating phases to the steam discharge is measured for determining time duration (t2, t3) of a subsequent preparation phase, where the detection of the stream discharge is prevented before a time point (ta). An independent claim is also included for a cooking appliance with a controller for executing a method for preparing cooked food in a cooking chamber.