Hot air apparatus

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional hot air tools with protective sleeves or shields suffer from overheating near the air outlet, necessitating a safe handling distance and the use of work gloves, which hinder fine motor skills and require frequent cooling breaks.

Innovation Solution

A hot air device with a protective tube surrounding the heating tube, featuring a non-uniform gap between the tubes at the air outlet end and through-openings in the wall, allowing ambient air intake for cooling, reducing surface temperature and enabling prolonged handling without gloves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a passive contact guard made of low thermal conductivity material is used, then protection against burns is improved, but the distance from the heating element must be increased which enlarges the tool size

Engineering Contradiction:
Improveburn protectionVSAvoidtool size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The protective tube is designed with non-uniform wall thickness, creating regions of different thermal insulation properties. The thicker sections provide enhanced protection where needed, while thinner sections allow for compact overall dimensions. This local variation in quality resolves the contradiction between adequate burn protection and compact tool size.

Inventive Principle:
Principle #3Local quality

2Temperature

If active cooling is provided by blowing air between the heating tube and protective tube, then surface temperature is reduced, but the cooling effect is insufficient at the air outlet end where temperatures remain above 60°C

Engineering Contradiction:
Improveprotective tube surface temperatureVSAvoidhandling comfort
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The protective tube incorporates non-uniform wall thickness with specific sections designed to enhance cooling efficiency at the air outlet end. This localized structural optimization ensures adequate temperature reduction in the critical handling area, resolving the contradiction between overall temperature reduction and specific area cooling effectiveness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention introduces a new dimension to the cooling system by varying the wall thickness profile along the tube length. This dimensional variation creates optimized thermal pathways that enhance convective cooling effectiveness at the air outlet end without requiring increased air flow throughout the entire tube.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Volume of moving object

If the protective tube is positioned close to the heating tube for compactness, then tool size is reduced, but surface temperature increases leading to burn risks

Engineering Contradiction:
Improvetool sizeVSAvoidburn risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The non-uniform wall thickness design allows the protective tube to maintain close proximity to the heating tube overall for compactness, while specific thicker sections provide enhanced thermal protection in areas where temperature exposure is highest. This resolves the contradiction between compact tool size and burn risk prevention.

Inventive Principle:
Principle #3Local quality

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 significantly reduces surface temperature at the air outlet end, allowing safe and efficient handling without gloves, improving workflow and fine motor skills by minimizing overheating and cooling interruptions.

Implementation Method 1

a second airflow can be directed in the same direction as the first airflow through the space between the heating tubes, so that the second airflow reduces the transfer of heat from the heating tube to the protective tube

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

a protective tube or contact guard that surrounds the heating tube... made of a material with low thermal conductivity

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

the air outlet end of the protective tube has at least one through-opening in a wall... causes a third airflow at the air outlet end through the at least one through-opening into the space between the heating tubes

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4671637B1Hot air apparatus
Publication Date: 2026.04.08 LEISTER TECHNOLOGIES AG
  • EP4671637B1 patent drawingFigure 1
  • EP4671637B1 patent drawingFigure 2
  • EP4671637B1 patent drawingFigure 3

AI summary

The present invention relates to a hot air device (100) with a heating tube (24) and a protective tube (10), wherein the protective tube (10) surrounds and is spaced apart from the heating tube (24), wherein the heating tube (24) has a hot air outlet end (30), wherein the protective tube (10) has a first main body (12) and an air outlet end (14) directed towards the hot air outlet end (30) of the heating tube (24), wherein a non-uniform distance is provided between the protective tube and the heating tube, wherein the distance in the air outlet end (14) is greater than the distance in a region (12a) adjacent to the air outlet end (14), and wherein the air outlet end (14) of the protective tube (10) has at least one through-opening (22) in a wall, preferably in the region of the distance widening.