Glass Furnace Load Sensing for Pre-Entry Heating Control
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Solution Overview
Problem
Existing methods for controlling the thermal treatment of glass sheets in furnaces are inefficient due to limitations in detecting the dimensions and patterns of glass loads, particularly with transparent materials, leading to inaccuracies and increased costs with multiple cameras, and delays in adjusting heating processes.
Innovation Solution
A method and device using at least one 2D camera to photograph the glass load before it enters the furnace, combined with a line scanner to provide real-time dimensional information, allowing for immediate adjustment of heating parameters, such as convection blowing and electric resistor current, to ensure precise thermal treatment without additional space or expense.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a row of optical sensors is used to detect glass load dimensions, then measurement information can be obtained, but the dimensional precision is limited by the distance between sensors and cannot detect distances between adjacent edges accurately
Solution Approach 1:
The patent transitions from one-dimensional linear sensor arrays to two-dimensional camera imaging. The camera captures the entire glass load area in a single photograph, enabling detection of distances between adjacent edges and accurate dimensional measurement without being constrained by sensor spacing. This dimensional change allows comprehensive load pattern recognition while reducing the number of measurement points required.
2Reliability
If multiple cameras are used to improve detection accuracy of glass load dimensions, then measurement reliability increases, but expenses and device complexity increase
Solution Approach 1:
The patent makes a single camera perform multiple functions: capturing glass load dimensions, identifying loading patterns, detecting glass positions, and providing data for heating control. By optimizing the camera's position, lighting conditions, and image processing algorithms, the system achieves reliable detection without requiring multiple cameras, thereby reducing cost and complexity while maintaining detection accuracy.
3Loss of information
If a streak camera is used to read load information, then shape, size and location information can be obtained, but delay problems occur and the entire glass load must pass through the measurement line before information is obtained
Solution Approach 1:
The patent positions the camera to capture images of the glass load before it enters the heating furnace, during the loading phase. This preliminary detection allows the control system to process the image data and prepare heating parameters in advance, eliminating delays associated with waiting for the entire load to pass through a measurement line. The loading pattern is identified and recorded prior to thermal treatment, enabling immediate control adjustments.
4Loss of information
If camera imaging is used to photograph glass load, then loading pattern information can be captured, but glass being transparent makes it difficult to detect and computer-determined dimensions are partially incorrect
Solution Approach 1:
The patent employs lighting that creates visible contrast between the transparent glass and its surroundings. By using specific lighting angles, intensities, or wavelengths, the glass edges and positions become clearly visible in the camera image. The image processing system then accurately identifies glass boundaries and dimensions based on these enhanced visual contrasts, overcoming the transparency issue and achieving precise dimensional measurement.
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
This approach enables reliable, precise control of the heating process by determining the loading pattern and dimensions before the glass load enters the furnace, reducing delay times and improving the quality of thermal treatment, thus preventing faults like bending and white haze formation.
Implementation Method 1
the glass load is photographed by at least one 2D camera
Implementation Method 2
the information of the camera image is sent to a computer
Implementation Method 3
selects the value of at least one adjustment parameter of the heating furnace... devices for adjusting the convection blowing and/or the current to be supplied to the electric resistors of the furnace
Implementation Method 4
devices for adjusting the convection blowing... current to be supplied to the electric resistors of the furnace
Data Source
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AI summary
The invention relates to a method for controlling a glass sheet heating furnace (2) using information describing a load of glass sheets, in which method the glass sheets are transported through a heating furnace (2), and, before thermal treatment, the glass load is photographed by at least one camera (4), the information of the camera image is sent to a computer (13), on the basis of which information the computer (13) defines the value of at least one dimension of the glass load, selects the value of at least one adjustment parameter of the heating furnace (2) on the basis of this dimension before the glass load has transferred into the heating furnace (2), in which method the information required for defining the dimensions of the glass load is also read by a line scanner (5), which information is sent to the computer (13), on the basis of which the computer (13) determines the value of at least one dimension of the glass load. The invention also relates to a device for controlling a glass sheet heating furnace (2) using information describing a load of glass sheets, the device comprising a computer (13), devices for adjusting the convection blowing of the furnace and/or the current supply to the electric resistors (6) of the furnace, at least one 2D camera (4) which is aligned to photograph a glass load on the transfer conveyor upstream of the heating furnace, and at least one line scanner (5), the measurement line of which covers the entire width of the glass loading area, and through which the glass load passes in thermal processing.