Low-Emission Glass Tempering With Zoned Heat Compensation

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Solution Overview

Problem

Existing glass tempering methods result in non-homogeneous heating due to varying heat absorption coefficients in zones with different heat absorption properties, leading to deformation and suboptimal quality.

Innovation Solution

A method and apparatus that differentially apply heat to glass zones with varying absorption coefficients using individually controlled heat sources and forced convection, monitored by a vision system to ensure uniform heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If uniform heating is applied to the entire glass pane, then the heating process is simple, but zones with different heat absorption coefficients experience non-homogeneous heating causing deformation

Engineering Contradiction:
Improveheating process simplicityVSAvoidheating uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The heating system is divided into multiple independent heating zones along the glass pane width. Each zone can be individually controlled to compensate for different heat absorption coefficients of screen-printed areas versus non-printed areas, achieving uniform overall heating while maintaining simple zone-by-zone control

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different heating powers are applied to different zones of the glass pane based on their specific heat absorption characteristics. Zones with higher absorption coefficients receive lower heating power, while zones with lower absorption coefficients receive higher heating power, ensuring homogeneous heating across the entire pane

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If screen-printed zones are present on the glass pane, then the glass can be customized with functional patterns, but these zones absorb heat differently causing non-homogeneous heating and deformation

Engineering Contradiction:
Improveglass customization capabilityVSAvoidheating uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The system performs preliminary scanning of the glass pane to detect screen-printed zones and their heat absorption coefficients before the heating process begins. This advance detection allows the control system to pre-calculate and set appropriate heating powers for each zone, compensating for the differential absorption caused by custom patterns

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses sensors to detect the actual temperature distribution and heat absorption characteristics of different zones during the heating process. This feedback information is used to dynamically adjust the heating power of each zone in real-time, ensuring uniform heating despite the presence of custom screen-printed patterns

Inventive Principle:
Principle #23Feedback

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

Achieves homogeneous heating of glass panes with different absorption zones, improving deformation control and quality.

Implementation Method 1

such zones can be provided with more or less heat, both by radiation and forced convection

Methodology Applied
Scientific EffectRadiation: Thermal Radiation

Implementation Method 2

such zones can be provided with more or less heat, both by radiation and forced convection

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP4617241A1Glass tempering process, in particular for low-emission glasses
Publication Date: 2025.09.17 MAZZAROPPI ENG SRL
  • EP4617241A1 patent drawingFigure 1(a)~1(c)
  • EP4617241A1 patent drawingFigure 2(a)~(2b1)
  • EP4617241A1 patent drawing

AI summary

The present invention relates to a method for tempering glass panes (20), with the following steps: A. acquiring an image of a glass pane (20) conveyed on conveyor rollers (30); B. acquiring a distribution map of heat absorption coefficient in said glass pane (20) conveyed on conveyor rollers (30); C. recognizing, by means of an electronic processing unit, the geometric shape and the overall dimensions of the glass pane (20) based on the image of step A; D. recognizing, by means of the electronic processing unit, based on the map of step B, the position of one or more parts (21, 22, 23) with respective heat absorption coefficient within the geometric shape of step C; E. conveying the glass pane (20) on said conveyor rollers (30) into a tempering furnace (100) provided with an array of resistances (50) and an array of blowing nozzles (40) ; F. determining, by means of an electronic processing unit, the position of said glass pane (20) and of said one or more parts (21, 22, 23) with a different heat absorption coefficient, inside the tempering furnace; G. individually activating the resistances (51, 52) of said array of resistances (50) and the nozzles (41, 42) of said array of nozzles (40) as a function of their proximity to said one or more parts (21, 22, 23), and in inversely proportional manner to the respective heat absorption coefficient. The invention also relates to a furnace configured to perform the method of the invention.