Flat Hollow Towel Rail Bar with Double-Insulated Heating Cable

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Solution Overview

Problem

Existing electric towel rails with flat, hollow bars face challenges in accommodating and insulating heating elements due to limited space, which affects electrical insulation and heat transfer, especially when exposed to water or water vapor, and requires complex designs to fit curved bars.

Innovation Solution

A heating cable with double electrical insulation is used, featuring rectilinear and curved sections that fit within the bar's geometry, with internal housings and partitions ensuring secure placement and insulation, allowing for efficient heat transfer and easy assembly, even in curved configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional heating element with double electrical insulation is used, then electrical insulation is ensured, but the overall size is too large to fit inside flat and thin drying bars

Engineering Contradiction:

Improveelectrical insulationVSAvoidheating element size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent uses a flexible heating cable with integrated thin-film insulation instead of traditional bulky insulating sheets. The cable has a flexible insulating sheath that provides double electrical insulation while maintaining a compact diameter suitable for insertion into flat drying bars. This resolves the contradiction by replacing rigid, space-consuming insulation layers with a flexible, space-efficient cable design.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The heating element combines multiple materials in a composite cable structure: a resistive wire core, flexible insulating sheath, and outer protective layer. This composite construction integrates both heating function and double electrical insulation in a compact form factor, allowing the element to fit within the limited space of flat drying bars while maintaining safety insulation standards.

Inventive Principle:

Principle #40Composite materials

2Volume of moving object

If heating elements are installed in flat drying bars with limited space, then the bar design is compact, but sufficient distance for double electrical insulation cannot be obtained

Engineering Contradiction:

Improvebar thicknessVSAvoidelectrical insulation distance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The flexible heating cable incorporates thin-film insulation layers directly onto the resistive wire core, providing the required double electrical insulation within the limited radial space of the bar. The thin-film approach eliminates the need for thick air gaps, enabling compact bar design while maintaining adequate insulation distances.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If a resistive wire with insulating sheets is used, then electrical insulation is provided, but the heating element lacks flexibility to adapt to curved drying bars

Engineering Contradiction:

Improveelectrical insulationVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces rigid insulating sheets with a flexible insulating sheath that forms part of a soft heating cable. This flexible construction allows the cable to bend and conform to curved drying bar geometries while maintaining continuous electrical insulation. The flexible cable can be easily routed around curves and installed in various bar configurations.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The heating element is designed as a flexible cable rather than a rigid structure, allowing it to dynamically adapt its shape to match the geometry of the drying bar. The cable can be bent, curved, and positioned as needed, providing versatility for different bar designs including curved configurations.

Inventive Principle:

Principle #15Dynamics

4Shape

If heating elements are installed in curved flat drying bars, then the design accommodates curved geometries, but standard heating elements cannot adapt to the curvature

Engineering Contradiction:

Improvebar curvatureVSAvoidheating element flexibility

Core Design Contradiction:

ShapeVSAdaptability or versatility

Solution Approach 1:

The heating cable is designed with high flexibility to dynamically adapt to curved bar geometries. The soft cable construction allows it to be bent and shaped to match the curvature of the drying bar, enabling installation in curved configurations that would be impossible with rigid heating elements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The flexible insulating sheath and cable construction enable the heating element to conform to curved surfaces. The flexible design allows the cable to be routed around curves and installed in curved drying bars without breaking or losing insulation integrity.

Inventive Principle:

Principle #30Flexible shells and thin films

5Adaptability or versatility

If water or water vapor enters the hollow bar, then the bar functions normally, but electrical insulation of the heating element is compromised

Engineering Contradiction:

Improvewater resistanceVSAvoidelectrical insulation

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The heating cable is provided with a continuous flexible insulating sheath that completely encloses the resistive wire and internal insulation layers. This sealed cable construction prevents water and water vapor from penetrating to the heating element, maintaining electrical insulation even when the bar is exposed to moisture during normal operation.

Inventive Principle:

Principle #30Flexible shells and thin films

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

The solution provides reliable double electrical insulation, easy mounting, and optimized heat transfer within the bar, extending the life of heating elements and simplifying assembly while maintaining insulation even when wet.

Implementation Method 1

heating elements, or hearts - or bodies - of heating... resistive wire... rapid rise in temperature... thermal homogeneity

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

double electrical insulation... insulating support sheet... insulating sheets sandwich the resistive wire support sheet... insulating parts or spacers

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 3

transmission of heat between the heating element and the bar... optimize the transmission of heat

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3096094B1Household electrical heating appliance comprising at least one flat hollow bar in which an electric heating element is housed

Publication Date: 2020.07.15 TEXAS DE FRANCE (SARL)

Figure 1
Figure 2~3b
Figure 4

AI summary

The invention relates to a domestic electric heating appliance comprising at least one vertical upright on which is fixed at least one hollow and flat bar (3) having two longitudinal edges (32a, 32b) and two transverse edges, an electric heating element (4 ) being housed in said bar, and in which: - the electrical heating element (4) is a cord having a sheath with double electrical insulation, which cord is formed of two straight heating sections (4a, 4b) connected by a curved section (4c), which curved section (4c) has a thickness less than those of the straight sections, - the bar (3) comprises arrangements (31 a, 31 b) for each receiving one of the straight sections (4a, 4b) of the cord (4), and an arrangement for receiving the curved section (4c) so that all of said cord is housed in said bar.