Sanitary washing device

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Sanitary washing devices face issues with unintentional jetting of high-temperature water due to failures in heating or temperature sensing components, which can cause discomfort or scalding, and existing protective circuits may fail to prevent such incidents effectively.

Innovation Solution

A sanitary washing device is designed with a first temperature sensor to monitor the heating part, a second temperature sensor downstream to detect water temperature, and a controlling part that determines if the second sensor is abnormal by comparing temperature changes, thereby preventing high-temperature water from being jetted by prohibiting water supply when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single temperature sensor is used to control water heating, then the device complexity is reduced, but the reliability of preventing high-temperature water jetting deteriorates due to potential sensor failures

Engineering Contradiction:
Improvetemperature sensor configurationVSAvoidprevention of high-temperature water jetting
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the temperature sensing function into two separate sensors: a first temperature sensor that monitors the heating element and a second temperature sensor that monitors the water temperature downstream. This segmentation allows independent monitoring of different stages, improving reliability without significantly increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first temperature sensor performs preliminary monitoring of the heating element before water is jetted. By detecting temperature changes at the heating stage, the system can prevent excessive heating before it affects the water temperature, enabling proactive safety intervention.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 3:

The patent implements a feedback mechanism where the controlling part continuously compares temperature readings from both sensors. When the first temperature sensor detects a temperature change exceeding a predetermined threshold while the second sensor shows minimal change, the system infers sensor abnormality and adjusts heating or water supply accordingly, creating a closed-loop safety feedback system.

Inventive Principle:
Principle #23Feedback

2Reliability

If temperature monitoring is enhanced with multiple sensors, then the safety against high-temperature water jetting is improved, but the device complexity increases

Engineering Contradiction:
Improvesafety against high-temperature water jettingVSAvoidtemperature sensor configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the monitoring functions of two temperature sensors into a single integrated control system. The controlling part processes inputs from both sensors and coordinates heating and water supply operations unifiedly, reducing control complexity despite having multiple sensors.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Both temperature sensors serve multiple functions: the first sensor monitors heating element temperature for preventive control, while also contributing to the overall temperature verification system. The second sensor similarly monitors water temperature and participates in the combined safety verification, making each sensor multi-functional and reducing redundant components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If the controlling part continuously monitors both temperature sensors, then the detection precision of sensor abnormalities is improved, but the use of energy increases

Engineering Contradiction:
Improvedetection of sensor abnormalityVSAvoidenergy consumption of controlling part
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The controlling part performs periodic comparison of temperature changes from both sensors at specific intervals during operation, rather than continuous monitoring. This periodic assessment maintains adequate detection precision for sensor abnormalities while significantly reducing the energy consumption of the control system.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the temperature data from both sensors to self-diagnose sensor abnormalities through automated comparison logic. The controlling part independently determines when a sensor is malfunctioning by detecting inconsistent temperature change patterns, eliminating the need for additional diagnostic hardware or manual checking.

Inventive Principle:
Principle #25Self-service

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 configuration effectively reduces the risk of jetting high-temperature water by accurately detecting sensor abnormalities and preventing water supply, enhancing user safety and comfort.

Implementation Method 1

a first temperature sensor configured to sense temperature of water heated by the heating part

Methodology Applied
Scientific EffectTemperature sensing: Thermistor

Implementation Method 2

a second temperature sensor provided downstream of the first temperature sensor and configured to sense temperature of the water

Methodology Applied
Scientific EffectTemperature sensing: Thermistor

Implementation Method 3

a heating part; a first temperature sensor configured to sense temperature of water heated by the heating part

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3461961B1Sanitary washing device
Publication Date: 2020.06.10 TOTO LTD
  • EP3461961B1 patent drawingFigure 1
  • EP3461961B1 patent drawingFigure 2
  • EP3461961B1 patent drawingFigure 3

AI summary

The sanitary washing device comprises: a heating part (440); a first temperature sensor (41) configured to sense temperature of water heated by the heating part (440); a second temperature sensor (42) provided downstream of the first temperature sensor (41) and configured to sense temperature of the water; a nozzle (473) provided downstream of the second temperature sensor (42) and configured to jet the water toward human private parts; and a controlling part (405) configured to determine that the second temperature sensor (42) is abnormal when change of the temperature sensed by the first temperature sensor (41) is larger than a predetermined first value and change of the temperature sensed by the second temperature sensor (42) is smaller than a predetermined second value.