Thermal Weeder Diffuser Structure for Wider Hot Air Coverage

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Solution Overview

Problem

Existing thermal weeders produce a narrow hot air jet, limiting the treatable area and requiring frequent repositioning, and the heated air cools quickly, necessitating high production temperatures that are difficult to maintain.

Innovation Solution

A diffuser with a deflector and shield/bell structure expands the hot air jet, combined with thermal insulation and elongated air circulation to maintain high temperatures and increase the treatable area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a narrow hot air jet is used, then the device structure is simple, but the treatable area is limited

Engineering Contradiction:
Improvetreatable areaVSAvoiddiffuser structure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent transitions from a narrow one-dimensional hot air jet to a wide two-dimensional distributed flow by implementing a diffuser with multiple outlets arranged in a grid pattern. This dimensional expansion allows the hot air to cover a treatable area of 50 cm² or more, resolving the contradiction between jet narrowness and treatable area.

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

Solution Approach 2:

The diffuser is segmented into multiple outlets (at least 4, preferably 9 arranged in a 3x3 grid) rather than using a single large opening. This segmentation distributes the hot air flow across multiple points, achieving wide coverage while maintaining structural simplicity and efficient heat distribution.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the hot air is diffused over a large area, then the treatable area increases, but the air temperature decreases quickly

Engineering Contradiction:
Improvetreatable areaVSAvoidhot air temperature
Core Design Contradiction:
Area of stationary objectVSTemperature

Solution Approach 1:

The patent applies thermal insulation specifically to the diffuser body and outlet regions where heat loss is most critical. This localized insulation approach maintains hot air temperature in the treatable area while allowing the diffuser to cover 50 cm² or more, resolving the contradiction between area expansion and temperature retention.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The elongated circulation passages (at least 10 cm in length) ensure continuous contact between the hot air and the diffuser interior surfaces, maximizing heat transfer to the treated area while minimizing cooling. This continuous thermal action maintains effective temperature across the expanded treatable area.

Inventive Principle:
Principle #20Continuity of useful action

3Temperature

If the production temperature is increased to compensate for cooling, then the temperature maintenance improves, but the device complexity and energy consumption increase

Engineering Contradiction:
Improvehot air production temperatureVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent implements thermal insulation on the diffuser body and circulation passages before the hot air exits to the treatable area. This preemptive thermal protection prevents heat loss during circulation, allowing the system to operate at lower production temperatures while maintaining effective treatment temperature, thus reducing energy consumption.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Area of stationary object

If a large diffuser is used to increase treatable area, then the coverage improves, but the repositioning frequency increases due to handling constraints

Engineering Contradiction:
Improvetreatable areaVSAvoiddevice repositioning ease
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The patent designs the diffuser as a lightweight, removable component that can be easily attached to and detached from the hot air generator. This dynamic design allows the large-area diffuser (50 cm² or more) to be conveniently repositioned between treatment zones, resolving the contradiction between coverage area and operational ease.

Inventive Principle:
Principle #15Dynamics

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 diffuser allows for a 10-fold increase in treatable area to 50 cm², maintaining effective weed control with reduced repositioning and improved temperature retention.

Implementation Method 1

The limiter means may comprise a thermal insulator

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

A diffuser with a deflector and shield/bell structure expands the hot air jet

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

produce hot air by means of a heat source, say electrical or by combustion, for example of gas

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 4

produce hot air by means of a heat source, say electrical

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4331357B1Thermal weed diffuser
Publication Date: 2026.02.18 EXEL INDUSTRIES
  • EP4331357B1 patent drawingFigure 1a~2
  • EP4331357B1 patent drawingFigure 3~4
  • EP4331357B1 patent drawingFigure 5~6

AI summary

Diffusers for thermal weeders, thermal weeders having diffusers and manufacture of thermal weeders having diffusers. The diffuser 2 may be for a thermal weeder 1 which is capable of producing a jet of hot air along an axis 3, and characterized in that the diffuser comprises at least one deflector 6 arranged across the hot air jet axis, so as to deflect hot air radially. The diffuser 2 may be for a thermal weeder 1, comprising a hollow body 8 substantially closed to the exclusion of a first opening 4 adapted to allow an air inlet from the weeder 1 to inside the diffuser 2, a second opening 5 capable of allowing the diffuser 2 to be applied to an area to be treated and a third opening able to allow egress of air to the outside of the diffuser 2, and characterized in that the diffuser further comprises a limiting means capable of limiting the cooling of the air.