Aircraft Drain Mast With Gradient Resistive Heating Against Freezing

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Solution Overview

Problem

Existing aircraft drain masts face issues with water freezing at high altitudes due to insufficient heating, leading to blockages, and conventional heating methods are inefficient and heavy.

Innovation Solution

A drain mast with a plastic line embedded with an electrically conductive material, where the proportion of conductive material increases from the connection end to the discharge end, allowing for self-regulating heating and efficient heat distribution, integrated with an aerodynamic fairing for protection and automation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional heating foils and insulating material are used to heat the drain mast, then the water can be prevented from freezing, but the device becomes heavy and complex

Engineering Contradiction:
Improvefreezing preventionVSAvoiddrain mast weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the heating method from external heating foils to internal resistive heating within the pipe wall itself. The pipe wall is given electrical conductivity through material selection or treatment, allowing direct Joule heating when current is applied, eliminating the need for separate heating foils and insulating material layers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The heating function is merged into the pipe structure itself. The pipe wall serves dual purposes: as the structural conduit for water flow and as the heating element through its electrical conductivity. This integration eliminates separate heating components and reduces overall system weight.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If heating foils are installed with insulating material and copper collars, then heating can be provided, but the manufacturing complexity and cost increase

Engineering Contradiction:
Improveheating functionVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The pipe is manufactured as a single integrated component with embedded heating capability. The electrical conductivity is incorporated into the pipe wall material itself, eliminating the need for separate heating foils, insulating material, and copper collars that would require multiple assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The complex multi-component heating system (heating foils, insulating material, copper collars) is extracted and replaced by a single simplified component: an electrically conductive pipe wall that provides heating intrinsically through its material properties.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If the drain mast outlets protrude from the aircraft outer skin with aerodynamic fairings, then contamination of the aircraft skin is prevented, but the heating requirement increases due to exposed ends

Engineering Contradiction:
Improvecontamination preventionVSAvoidheating energy consumption
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent changes the thermal parameter distribution along the pipe by providing enhanced heating at the discharge end where temperature drops most sharply. The electrical conductivity and heating power are concentrated at the protruding outlet section to counteract the ambient temperature at high altitude, while the insulated portion requires less heating energy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The heating capability is distributed non-uniformly along the pipe length, with higher heating power concentrated at the discharge end that protrudes into the cold environment. The insulated portion of the pipe receives less heating, optimizing energy usage by applying heat only where most needed.

Inventive Principle:
Principle #3Local quality

4Weight of moving object

If the line is made from plastic with embedded conductive material, then the structure is simplified and lightweight, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvedrain mast weightVSAvoidconductive material embedding precision
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent uses composite material construction where electrically conductive material is embedded within the plastic pipe wall. This creates a lightweight structure that combines the low density of plastic with the electrical conductivity needed for heating, eliminating heavy metal pipes while maintaining functional requirements.

Inventive Principle:
Principle #40Composite materials

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 a lightweight, energy-efficient, and damage-resistant drain mast that maintains consistent heating from the connection to the discharge end, preventing freezing and reducing manufacturing costs through automation.

Implementation Method 1

The line comprises a plastic in which an electrically conductive material is embedded, by means of which the line can be electrically heated by passing a heating current through the conductive material

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

A proportion of the embedded conductive material in the line increases in the line direction per unit length from the connection end of the line to the discharge end such that the heating power introduced into the line per unit length increases from the connection end to the discharge end

Methodology Applied
Scientific EffectThermal gradient: Temperature Gradient

Data Source

PatentEP4112446B1Drain mast
Publication Date: 2025.08.27 AIRBUS OPERATIONS GMBH
  • EP4112446B1 patent drawingFigure 1~4
  • EP4112446B1 patent drawingFigure 5~6

AI summary

A drain mast for an aircraft is shown and claimed for draining water from the aircraft interior. The mast comprises a conduit extending in one direction from a connection end to a discharge end. The connection end is designed to connect to another conduit inside the aircraft through which water flows into the drain mast. The discharge end is designed to discharge the water into the aircraft's surroundings. The conduit is made of a plastic material in which a conductive material is embedded. This conductive material allows the conduit to be electrically heated by passing a heating current through it. The proportion of the embedded conductive material in the conduit increases per unit length from the connection end to the discharge end, such that the heating power introduced into the conduit per unit length increases from the connection end to the discharge end.