Asymmetric Reflective Foil for Gun Barrel Thermal Insulation

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Solution Overview

Problem

Existing heat protection sleeves for weapon barrels fail to effectively mitigate temperature differences caused by uneven heating, leading to barrel distortion and accuracy issues due to air convection and asymmetrical heat transfer.

Innovation Solution

A reflective foil with high infrared reflection properties is applied to the inner surface of the metal casing opposite the lower area of the weapon barrel, compensating for temperature differences by reflecting heat rays and reducing heat transfer to the underside.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a metal heat protection sleeve surrounds the weapon barrel, then thermal insulation is improved, but air convection causes uneven heating and temperature differences between upper and lower sides

Engineering Contradiction:
Improvethermal insulationVSAvoidbarrel accuracy
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by providing thermal insulation only on the lower side of the weapon barrel (between 6 o'clock and 9 o'clock positions) rather than uniformly around the entire barrel. This asymmetric insulation configuration compensates for the natural convection currents that cause the lower side to cool more, thereby balancing the temperature distribution and maintaining barrel accuracy.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent implements local quality by applying thermal insulation selectively to specific regions (lower side) of the weapon barrel where it is most needed, rather than uniformly across the entire surface. The insulation layer is positioned at the lower rear portion where convection effects are most pronounced, providing targeted thermal management.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If thermal insulation is applied uniformly around the barrel, then heat loss is reduced, but temperature differences cause barrel distortion requiring costly compensation

Engineering Contradiction:
Improveheat lossVSAvoidbarrel accuracy
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by providing thermal insulation only on the lower side of the weapon barrel (between 6 o'clock and 9 o'clock positions) rather than uniformly around the entire barrel. This asymmetric insulation configuration compensates for the natural convection currents that cause the lower side to cool more, thereby balancing the temperature distribution and maintaining barrel accuracy.

Inventive Principle:
Principle #4Asymmetry

3Temperature

If the entire lower half of the protective pipe sleeve is covered with adhesive, then heat reflection is maximized, but manufacturing complexity increases

Engineering Contradiction:
Improvetemperature compensationVSAvoidmanufacturing simplicity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies partial action by covering only the critical lower half portion (6 o'clock to 9 o'clock positions) with adhesive and reflective foil, rather than the entire lower half or full circumference. This provides sufficient temperature compensation while minimizing the amount of material and labor required, balancing performance with manufacturing ease.

Inventive Principle:
Principle #16Partial or excessive action

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 effectively compensates for temperature differences between the upper and lower sides of the weapon barrel, reducing barrel distortion and maintaining accuracy by reflecting infrared radiation and minimizing heat transfer to the underside, thus addressing the issue of uneven heating.

Implementation Method 1

a reflective foil which is non-positively connected to the metal casing and reflects infrared light well is arranged on the inner surface of the metal casing facing the underside of the weapon barrel

Methodology Applied
Scientific EffectInfrared radiation reflection: Reflection

Implementation Method 2

so that when the weapon barrel heats up, the temperature differences between the upper and lower sides of the weapon barrel are at least partially compensated

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

The static layer of air between the tube and the metal shell serves as a heat insulator

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 4

air convection forms between the barrel surface and the metal casing when the gun barrel is fired warm, which means that the underside of the gun barrel cools down more than the top of the barrel

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2058622B1Heat jacket for a gun barrel
Publication Date: 2013.05.15 RHEINMETALL WAFFE MUNITION GMBH
  • EP2058622B1 patent drawingFigure 1~2

AI summary

The invention relates to a thermal insulation sleeve (2) for a gun barrel (1), in particular for a cannon barrel, wherein the thermal insulation sleeve (2) comprises a metal shell (3) surrounding the gun barrel (1). To avoid uneven heating of the barrel surface within the thermal insulation sleeve (2) in a simple and cost-effective manner, the invention proposes providing an additional, highly reflective area on the inner surface (6) of the metal shell (3) opposite the underside (5) of the gun barrel (1), so that when the gun barrel (1) is heated, the temperature differences between the top and bottom of the gun barrel (1) are at least partially compensated. A reflective foil (4) is provided as the highly reflective area, which is bonded to the metal shell (3).