Jet Water Conduit Layout for Compact Leak-Safe Flush Toilets

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Solution Overview

Problem

Flush toilets with resin downstream side water conduits are prone to waste accumulation and require a higher connecting portion to maintain watertightness, limiting design flexibility and compactness.

Innovation Solution

The connecting portion between the upstream and downstream water conduits is positioned on the rear side and lower than the pooled water surface, using porcelain for the downstream conduit, with a sealing member to ensure watertightness, allowing for a compact layout and improved pressure efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the downstream side water conduit is made of resin, then freedom of design for the jet water conduit is enhanced, but waste is likely to stick to the downstream side water conduit

Engineering Contradiction:
Improvefreedom of designVSAvoidwaste accumulation
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The jet water conduit is divided into two separate conduits: an upstream side water conduit made of resin and a downstream side water conduit made of porcelain. This segmentation allows each conduit to be made of the most suitable material for its specific function, resolving the contradiction between design freedom and waste resistance.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the connecting portion between the upstream side water conduit and the downstream side water conduit is located at a position higher than the pooled water surface, then watertightness is maintained, but a compact layout cannot be achieved

Engineering Contradiction:
ImprovewatertightnessVSAvoidlayout compactness
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

A sealing member is introduced as an intermediary element at the connecting portion between the upstream and downstream side water conduits. This sealing member ensures watertightness at the connection, allowing the connecting portion to be located lower than the pooled water surface while maintaining reliability, thus achieving a compact layout.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If the connecting portion is located lower than the pooled water surface, then a compact layout is achieved, but there is a fear that flush water would leak or backflow would occur

Engineering Contradiction:
Improvelayout compactnessVSAvoidleak prevention
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The sealing member is pre-installed at the connecting portion before the toilet is put into service. This preliminary action ensures that watertightness is established in advance, preventing leak and backflow issues even when the connecting portion is located lower than the pooled water surface, thus enabling compact layout without compromising reliability.

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

This configuration achieves a more compact layout and enhances design freedom while preventing leaks, improving pressure loss efficiency and maintaining watertightness in jet spouting flush toilets.

Implementation Method 1

a jet spout port configured to spout out flush water into an inside of the discharge trap pipe in a rearward direction

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP4707480A1Flush toilet
Publication Date: 2026.03.11 TOTO LTD
  • EP4707480A1 patent drawingFigure 1
  • EP4707480A1 patent drawingFigure 2
  • EP4707480A1 patent drawingFigure 3

AI summary

A flush toilet includes: a main toilet unit having a bowl portion and a discharge trap pipe extending from a lower part of the bowl portion; a jet spout port configured to spout out flush water into an inside of the discharge trap pipe in a rearward direction; and a jet water conduit configured to supply the flush water to the jet spout port, wherein the jet water conduit has a downstream side water conduit extending to the jet spout port and an upstream side water conduit connected to the downstream side water conduit, the downstream side water conduit is made of porcelain, and a connecting portion between the upstream side water conduit and the downstream side water conduit is located on a rear side with respect to the jet spout port and lower than a pooled water surface.