Cooking Chamber Pressure Sensing for Adaptive Steam Control

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Solution Overview

Problem

Existing cooking process monitoring technologies are not robust and are susceptible to interference, providing inaccurate and delayed measurements of steam release, which hinders precise control of the cooking process, especially in varying food sizes and quantities.

Innovation Solution

A cooking appliance with a sensor device that measures pressure differences within the cooking chamber and steam outlet to accurately determine the source vapor rate, allowing for precise control of the cooking process by distinguishing between technically generated and food-derived steam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional humidity sensors are used to determine steam release rate, then the measurement can be implemented, but the measurement becomes unreliable at high humidity and impossible at 100% humidity

Engineering Contradiction:
Improvesteam release rate measurementVSAvoidmeasurement reliability at high humidity
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a differential pressure sensor as an intermediary measurement device that indirectly determines steam release rate by measuring pressure differences across a restriction element, bypassing the limitations of direct humidity sensing in high-humidity environments

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the measurement parameter from direct humidity measurement to pressure difference measurement, which remains reliable even when humidity reaches 100%, thereby resolving the measurement reliability issue

Inventive Principle:
Principle #35Parameter changes

2Loss of information

If gas sensor arrays are used to detect cooking state, then information about cooking status can be derived, but the system becomes complex and susceptible to interference

Engineering Contradiction:
Improvecooking status informationVSAvoidsensor system complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent extracts only the essential measurement information (steam release rate via pressure difference) needed for cooking control, eliminating the complexity of gas sensor arrays while maintaining sufficient cooking status detection capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces complex chemical sensing (gas sensor arrays) with a simpler mechanical measurement approach (differential pressure sensing), reducing system complexity and susceptibility to interference

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If pressure sensors are used to determine steam release, then measurement can be achieved, but the measurement is delayed and less accurate

Engineering Contradiction:
Improvesteam release rate measurementVSAvoidmeasurement delay
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent positions the first pressure sensor upstream of the restriction element to detect pressure changes before they occur downstream, providing earlier and more accurate steam release rate measurement

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

Enables precise and reliable monitoring of the cooking process, allowing for adaptive cooking based on food parameters, improved humidity control, and efficient energy management, reducing the risk of overcooking or undercooking.

Implementation Method 1

a sensor device for determining a pressure difference between two locations inside the cooking appliance, with at least one of the locations being inside the duct

Methodology Applied
Scientific EffectPressure difference measurement: Pressure Gradient

Data Source

PatentEP2154435B1Method for monitoring and controlling a cooking process
Publication Date: 2016.03.16 RATIONAL AG
  • EP2154435B1 patent drawingFigure 1~2
  • EP2154435B1 patent drawingFigure 3~4
  • EP2154435B1 patent drawingFigure 5~6

AI summary

The cooking appliance comprises a cooking area (10), a channel (16) over which a gaseous medium passes from the cooking area, a sensor unit (24, 26, 28) for determining the pressure difference between two places in interior (12, 18) of the cooking appliance, a control device (36) to control the cooking process of the cooking goods present in the cooking area in dependent upon the determined pressure difference, a moisture sensor to determine moisture value in the cooking area, a temperature sensor to determine temperature in the cooking are and/or a density sensor. The cooking appliance comprises a cooking area (10), a channel (16) over which a gaseous medium passes from the cooking area, a sensor unit (24, 26, 28) for determining the pressure difference between two places in interior (12, 18) of the cooking appliance, a control device (36) to control the cooking process of the cooking goods present in the cooking area in dependent upon the determined pressure difference, a moisture sensor to determine moisture value in the cooking area, a temperature sensor to determine temperature in the cooking are and/or a density sensor to determine the density of the gaseous medium in the cooking area, for determining the load of the cooking goods in the cooking area and/or the discharge condition of the cooking goods, a control- or regulating unit that is connected with the sensor unit, the processing unit, the moisture sensor, the temperature sensor and/or density sensor on one hand and with a further function unit of the cooking appliance on the other hand. One of the places lies in the interior of the channel. The cooking appliance is arranged to determine a cooking product present in the cooking area, a gas volume stream emerging from the cooking area, a gas measuring stream emerging from the cooking area, a load with which the cooking area is loaded, and/or a discharge condition of the cooking product in the cooking area, weather the cooked goods are frozen or fresh, from the pressure difference and/or the progress of the pressure difference over the time of a source steam rate. The channel comprises a flow for a fluid medium from the cooking area. The interior of the cooking appliance comprises interior of the cooking area and the interior of the channels, where the another place lies in the interior of the cooking area. Both places lie in the interior of the channel. The sensor unit is arranged to produce a difference signal proportional to the pressure difference between the both places in the interior of the cooking appliances. The sensor unit for determining the pressure difference between both places in the interior of the cooking appliances comprises a first pressure sensor for producing a first sensor signal, a second pressure sensor for producing a second sensor signals, a processing unit to form a difference signal from the first sensor signal and the second sensor signal, and a difference pressure sensor for producing a corresponding difference signals. The sensor unit or the processing unit is arranged to determine a value proportional to the product from gas volume stream or gas measuring stream stepping from the cooking area, from the difference signal. The processing arrangement is implemented with the control or regulating unit. The further function unit comprises a heating device, a cooling device, a blower device, a pumping device, an energy storage device, a moisture supply device and/or moisture removal device. An independent claim is included for a method for observing the cooking process of cooking goods in a cooking area of a cooking appliance.