Pressure Cooker Heating Control Using Temperature-Based Pressure Sensing

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Solution Overview

Problem

The frequent operation of displacement-based pressure switches in electric pressure cookers leads to reduced service life and inaccurate pressure control, risking abnormal high pressure or leakage.

Innovation Solution

A method and device that utilize a temperature sensor to detect temperature values corresponding to pressure thresholds, calculating a temperature reference value to control the heating unit based on these values, thereby reducing the pressure switch's usage frequency and improving pressure control precision.

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 will be moved frequently which adversely affects service life and shortens the service life of the electric pressure cooker

Engineering Contradiction:

Improvepressure control reliabilityVSAvoidservice life of pressure switch

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent replaces the mechanical displacement-based pressure switch with a non-contact sensing system using a magnetic field sensor and a magnetic float. The magnetic float moves with pressure changes and actuates the magnetic field sensor without mechanical contact, eliminating wear and extending service life while maintaining pressure control reliability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a magnetic float as an intermediary between the pressure system and the sensing system. The magnetic float converts pressure-induced mechanical displacement into magnetic field changes that can be detected by the magnetic field sensor, allowing indirect measurement without direct mechanical contact between the sensor and moving parts.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a displacement-based pressure switch is used to control heating, then pressure control can be achieved, but the range over which the pressure value can be maintained is affected by accuracy of the pressure switch and the pressure switch is likely to become invalid leading to abnormal high pressure or pressure leakage

Engineering Contradiction:

Improvepressure control safetyVSAvoidpressure measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical pressure switch with a magnetic field-based sensing system that has no mechanical wear components. The magnetic field sensor detects the position of the magnetic float to determine pressure levels, providing continuous and accurate measurement without the degradation associated with mechanical wear, thereby improving both measurement precision and safety.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a feedback control system where the magnetic field sensor continuously monitors the magnetic float position and sends signals to the control unit, which adjusts the heating element accordingly. This closed-loop feedback ensures accurate pressure maintenance and prevents abnormal high pressure or leakage by responding to real-time pressure changes.

Inventive Principle:

Principle #23Feedback

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 and maintains pressure within a precise range, enhancing cooking safety by reducing the pressure switch's wear and tear and stabilizing pressure control.

Implementation Method 1

a displacement-based pressure switch is usually used to control heating for all electric pressure cookers

Methodology Applied

Scientific EffectDisplacement-based pressure sensing: Displacement

Implementation Method 2

detecting by the temperature sensor a first temperature value when the detected pressure value rises

Methodology Applied

Scientific EffectThermal detection: Temperature Gradient

Implementation Method 3

a heater of the electric pressure cooker is powered for heating

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS10973362B2Cooking apparatus, control method thereof and control device

Publication Date: 2021.04.13 FOSHAN SHUNDE MIDEA ELECTRICAL HEATING APPLIANCES MFG CO LTD

AI summary

A pressure cooking apparatus, a method and device for controlling the same are provided. During a heating process of the apparatus, the device detects a pressure value inside the inner liner, a first temperature value when the detected pressure value rises to a first preset pressure threshold, and a second temperature value when the detected pressure value drops from the preset first pressure threshold to a second preset pressure threshold. Next the device acquires a temperature reference value according to a preset setting strategy using the first temperature value and the second temperature value and then compares a current temperature value detected by the temperature sensor with the temperature reference value. Finally, the device starts or stops the heating process based on the comparison result, thus reducing the on/off frequency of the apparatus and controlling the pressure inside the cooking apparatus more precisely and smoothly.