Toilet Rim Water Level Sensor Positioning for Overflow Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing flush toilets with water level detection sensors are prone to erroneous detections during normal flushing or manual cleaning, as the sensors can be affected by changes in water level or interference from human hands.

Innovation Solution

The water level detection sensor is positioned inside the rim of the toilet, upstream of the rim water passage, and installed on the base portion of the rim, allowing it to detect rising water levels before overflow without being affected by normal flushing or manual cleaning activities, and can be easily installed using a non-ceramic base plate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the water level detection sensor is provided at the bottom surface of the rim water supply chamber or rim portion to detect overflow, then the sensor can detect water overflow caused by clogging, but the sensor may erroneously detect normal flush water level changes or manual cleaning activities

Engineering Contradiction:
Improveclogging detection accuracyVSAvoidwater level detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The water level detection sensor is extracted from the general rim water supply chamber area and specifically positioned in the rim headrace upstream of the spouting pipe. This extraction places the sensor in a location that is not affected by normal flush water flow, eliminating erroneous detections during flushing and manual cleaning while maintaining the ability to detect overflow caused by clogging.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If the water level detection sensor is positioned upstream in the rim headrace, then the sensor is protected from normal flush water and manual cleaning interference, but the sensor must be precisely positioned to detect overflow before it occurs

Engineering Contradiction:
Improvedetection stabilityVSAvoidsensor installation position precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The rim headrace structure serves as an intermediary that channels water flow in a controlled manner. By positioning the sensor within this intermediary structure upstream of the spouting pipe, the system creates a natural water flow pattern where normal flush water does not reach the sensor, yet overflow water from clogging will accumulate and be detected. This intermediary structure simplifies installation positioning requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the sensor is positioned to detect overflow early, then water overflow can be prevented, but the sensor may be affected by water pressure changes during normal flushing

Engineering Contradiction:
Improveoverflow prevention capabilityVSAvoidwater pressure interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sensor position is extracted from the main flush water flow path and placed in the upstream rim headrace area. This extraction removes the sensor from the harmful effects of high water pressure and turbulent flow during normal flushing, while still allowing detection of water level rise that indicates clogging and potential overflow.

Inventive Principle:
Principle #2Taking out (Extraction)

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 prevents erroneous detections during normal use and manual cleaning, ensuring accurate detection of clogging and preventing water overflow, while maintaining a sleek design and reducing installation costs.

Implementation Method 1

The water level detection sensor detects the height of the surface of seal water based on the time it takes for an emitted ultrasonic wave to be reflected by a surface of the seal water inside the bowl portion and return

Methodology Applied
Scientific EffectUltrasonic wave reflection: Ultrasound

Data Source

PatentEP3418459B1Flush toilet
Publication Date: 2024.04.03 LIXIL CORP
  • EP3418459B1 patent drawingFigure 1
  • EP3418459B1 patent drawingFigure 2
  • EP3418459B1 patent drawingFigure 3

AI summary

A flush toilet includes: a toilet main body; a rim which is provided on an upper portion of a toilet bowl of the toilet main body and which flows a flush water into the toilet bowl; and a water level detection sensor which is provided inside the rim.