Cooking device, and control method and control apparatus therefor

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Solution Overview

Problem

Existing electric pressure cookers face reduced service life and accuracy issues in maintaining pressure due to frequent operation of displacement-based pressure switches, leading to potential high pressure or leakage risks.

Innovation Solution

A method and device that utilize a heating unit, pressure detecting unit, and temperature sensor to control the cooking apparatus by setting and updating a temperature reference value based on detected temperature values, allowing the heating unit to start or stop heating based on temperature comparisons, thereby reducing pressure switch usage and maintaining pressure within precise limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a displacement-based pressure switch is used to control heating in an electric pressure cooker, then the pressure value can be maintained in a predetermined range, but the pressure switch moves frequently which reduces its service life and affects the overall reliability of the device

Engineering Contradiction:
Improveservice life of pressure switchVSAvoidpressure control accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical displacement-based pressure switch with a sensing system that detects pressure through displacement of a flexible wall without mechanical contact. The flexible wall moves in response to pressure changes, and this displacement is detected by a sensor (such as a capacitive, inductive, or optical sensor) that converts the mechanical displacement into an electrical signal for control purposes, eliminating wear from mechanical friction.

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

Solution Approach 2:

The patent introduces a flexible wall as an intermediary between the pressure environment and the sensing mechanism. The flexible wall transmits pressure information through its displacement while isolating the sensing system from direct mechanical stress and wear, allowing accurate pressure detection without subjecting the sensor to harsh mechanical conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the pressure switch is used to control heating cycles, then pressure control is achieved, but the frequent on-off operation causes the pressure switch to become invalid, creating safety risks

Engineering Contradiction:
Improvesafety of pressure controlVSAvoidservice life of pressure switch
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces the mechanical pressure switch with a non-contact sensing system that uses a flexible wall coupled with an electrical sensor. This eliminates mechanical wear and failure modes, providing a more reliable and durable pressure control mechanism that maintains safety over extended service life without the frequent on-off wear problems of mechanical switches.

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

Solution Approach 2:

The patent changes the control parameter from mechanical displacement threshold switching to continuous electrical signal monitoring. By converting the pressure detection into an electrical signal that can be processed and controlled with hysteresis bands and dead zones, the system achieves more graceful control transitions and avoids the abrupt wear-inducing on-off cycles of mechanical switches.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a displacement-based pressure switch is used, then pressure control is possible, but the range over which pressure can be maintained is affected by the accuracy limitations of the pressure switch

Engineering Contradiction:
Improvepressure maintenance rangeVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical pressure switch with an electrical sensing system that offers superior resolution and accuracy. Electrical sensors can detect much smaller displacements and provide more precise pressure measurements, enabling tighter pressure control ranges without proportionally increasing system complexity, as the sensing and control electronics are already present in modern pressure cookers.

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

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 prolongs the service life of the cooking apparatus, improves cooking safety by maintaining pressure in a stable and precise range, and reduces the frequency of pressure switch operation, preventing damage and ensuring accurate pressure control.

Implementation Method 1

a pressure detecting unit... detecting by the pressure detecting unit a pressure value inside the inner liner

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a heating unit... in a heating process of the heating unit

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 3

a temperature sensor... detecting by the temperature sensor a first temperature value

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3424374B1Cooking device, and control method and control apparatus therefor
Publication Date: 2020.12.23 FOSHAN SHUNDE MIDEA ELECTRICAL HEATING APPLIANCES MFG CO LTD
  • EP3424374B1 patent drawingFigure 1
  • EP3424374B1 patent drawingFigure 2
  • EP3424374B1 patent drawingFigure 3~4

AI summary

A cooking apparatus, a method and device for controlling the same are provided, and the method includes: detecting by the pressure detecting unit a pressure value inside the inner liner in a heating process of the heating unit; detecting by the temperature sensor a first temperature value when the pressure value detected rises to a first pressure threshold preset; detecting by the temperature sensor a second temperature value when the pressure value detected drops from the first pressure threshold preset to a second pressure threshold preset; acquiring a temperature reference value according to a preset setting strategy with the first temperature value and the second temperature value; and comparing a current temperature value detected by the temperature sensor with the temperature reference value, and controlling the heating unit to start or stop based on a comparison result, thus reducing use frequency of the pressure detecting unit, and controlling the pressure inside the inner liner of the cooking apparatus more precisely and stably.