Low-Profile Concealed Cistern With Horizontal Flush Routing

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Solution Overview

Problem

Conventional concealed cistern modules require a significant vertical extension due to their design, limiting installation options to walls with sufficient height, making them unsuitable for low-rise installations and restricting interior design flexibility.

Innovation Solution

A low-profile concealed cistern module design featuring a cistern with a drain valve and flush pipe bend that minimizes vertical extent while maintaining sufficient flushing effectiveness through optimized fluid dynamics and geometry, including a flush pipe bend with reduced fluid friction and a compact cistern volume.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a conventional concealed cistern module is used, then sufficient flushing performance is achieved, but the vertical extension is too large for low-rise wall installations

Engineering Contradiction:

Improvevertical extensionVSAvoidflushing performance

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The invention repositions the flush pipe opening from a vertical orientation to a horizontal orientation, changing the spatial dimension of the flushing mechanism. This allows the cistern to achieve sufficient flushing performance with a reduced vertical footprint, enabling installation on low-rise walls while maintaining effective water delivery to the toilet bowl

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention modifies key geometric parameters of the cistern system, including the position of the flush pipe opening (moved to the side wall rather than bottom), the angle of the flush pipe bend (optimized to 45-135 degrees), and the vertical distance between the flush pipe opening and fill line (reduced to 200-350 mm). These parameter changes enable compact vertical dimensions while preserving flushing effectiveness

Inventive Principle:

Principle #35Parameter changes

2Length of moving object

If the vertical distance between fill line and flush pipe opening is reduced, then the vertical footprint is minimized, but the flow velocity and impact pressure of flush water may be insufficient

Engineering Contradiction:

Improvevertical distance from fill line to flush pipe openingVSAvoidimpact pressure of flush water

Core Design Contradiction:

Length of moving objectVSForce

Solution Approach 1:

The invention employs a curved flush pipe bend with optimized radius and angle (45-135 degrees) to guide water flow from the cistern to the toilet bowl. The curved geometry maintains flow velocity and directs water with sufficient impact pressure, compensating for the reduced vertical drop distance while ensuring effective flushing performance

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

Enables installation on low-rise walls by reducing the vertical footprint without compromising flushing performance, offering new installation possibilities and design flexibility.

Implementation Method 1

In a closed state, the drain valve rests in a sealing manner on an edge surrounding the drain opening to prevent flush water stored in the wall from escaping from the drain opening

Methodology Applied

Scientific EffectSealing:

Implementation Method 2

The flush pipe bend connected to the drain opening comprises a curved section running between the flush pipe opening and the drain opening

Methodology Applied

Scientific EffectFluid flow through curved conduit:

Implementation Method 3

The drain valve has an overflow opening which, in the closed state and in particular also in the open state, is fluidly connected to the flush pipe opening and whose vertical position defines a fill limit

Methodology Applied

Scientific EffectOverflow discharge:

Implementation Method 4

The flush water falls from the cistern's drain opening before flowing into the flush inlet of the toilet bowl, at a flow velocity that depends on the fill level of the stored flush water in the cistern, the fall height, and the overall geometry of the cistern

Methodology Applied

Scientific EffectGravity: Gravitation

Data Source

PatentEP4060135B1Low-profile flush-mounted cistern

Publication Date: 2025.10.08 TECE GMBH

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Figure 2a

AI summary

The invention relates to a low-profile concealed cistern module 100, comprising a cistern 1, which includes a flush valve 10 and a wall 12 having an inlet opening 24 and an outlet opening 23 on its vertical underside, and a flush pipe bend 2 connected to the outlet opening 23 in a fluid-conducting manner, which comprises a flush pipe opening 20 and a curved section 21 connecting the flush pipe opening 20 to the outlet opening 23 in a fluid-conducting manner. In a closed state, the flush valve 10 rests on a rim 141 surrounding the outlet opening 23, sealingly preventing the escape of flush water stored in the wall 12 from the outlet opening 14, and in an open state is vertically spaced from the rim 141 to allow the outlet opening 14 to open, wherein the flush valve 10 has an overflow opening 25 which is connected to the flush pipe opening 20 in a fluid-conducting manner when closed.Flush pipe bend 2, wall 12 and drain valve 10 are designed in such a way that the flush pipe opening is perpendicular to the vertical direction Z and its vertical center is spaced a maximum of 32 cm away from the drain opening 14.