High-Temperature Vacuum Fining for Submerged-Combustion Glass
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Solution Overview
Problem
Conventional fining techniques for conventionally-melted glass are not well adapted for submerged combustion (SC)-produced glass, which has higher volumetric proportions of homogeneously distributed gas bubbles and different gas species, leading to insulating foam layers and prolonged fining processes.
Innovation Solution
A vacuum induction fining apparatus with a vertically-elongated housing and induction heating is used to separate and burst gas bubbles under subatmospheric pressure, followed by rapid intermittent cooling of fined molten glass before thermal conditioning, reducing residence time and tank sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fining techniques are used for SC-produced glass, then the process can be simple, but the fining time is prolonged and the foam layer blocks heat transfer
Solution Approach 1:
The patent changes the pressure parameter from atmospheric to subatmospheric (vacuum) conditions in the fining tank. This pressure change causes the foam layer to collapse and gas bubbles to detach from the glass melt surface, enabling rapid fining without the heat transfer blocking problem that occurs under atmospheric conditions.
Solution Approach 2:
The patent creates a vacuum environment (subatmospheric pressure) in the fining tank, which acts as an inert environment that prevents atmospheric gases from being trapped in the foam layer. This vacuum environment allows efficient gas bubble removal and rapid fining of SC-produced glass.
2Productivity
If the fining tank is made larger to accommodate foam separation, then more glass can be processed, but the system size and complexity increase
Solution Approach 1:
The vacuum environment causes gas bubbles to detach rapidly from the glass melt surface and rise through the melt. This rapid bubble removal allows the fining process to occur in a compact tank volume, as the foam layer collapses and gas is removed quickly without requiring large separation spaces.
Solution Approach 2:
The patent uses vacuum pressure differential (pneumatic principle) to drive the fining process. The subatmospheric pressure creates a pressure gradient that rapidly draws gas bubbles out of the melt and through the tank, enabling efficient fining in a compact system without requiring large tank volumes for foam separation.
3Manufacturing precision
If chemical fining agents are added to the SC melter, then gas bubbles can be removed, but excessive volatilization and unwanted chemical side reactions occur
Solution Approach 1:
The patent extracts the fining operation from the SC melter and performs it separately in a dedicated fining tank under vacuum conditions. This separation allows gas bubble removal without adding chemical fining agents to the melt, thereby avoiding volatilization and unwanted chemical side reactions while maintaining glass quality.
Solution Approach 2:
The patent replaces chemical fining agents with a physical vacuum-based fining mechanism. Instead of using chemicals to remove gas bubbles, the system uses vacuum pressure differential and bubble detachment mechanisms to physically remove gas bubbles from the melt, eliminating the harmful volatilization and side reactions associated with chemical agents.
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 process efficiently removes gas bubbles and conditions molten glass quickly, allowing for a compact glass-producing system with maintained throughput and operational flexibility.
Implementation Method 1
inductively heating the molten glass bath contained within the fining tank to maintain the molten glass bath within a temperature range for glass fining
Implementation Method 2
maintaining the interior fining chamber at a subatmospheric pressure
Implementation Method 3
promote the ascension of gas bubbles upwards through the molten glass bath until the bubbles eventually reach a top surface of the glass bath and burst
Implementation Method 4
The combustible gas mixture autoignites and the resultant combustion products cause vigorous stirring and turbulence as they are discharged through the glass melt
Implementation Method 5
The combustible gas mixture autoignites and the resultant combustion products cause vigorous stirring and turbulence
Data Source
AI summary
A method of producing glass includes discharging an outflow (22, 1022) of fined molten glass from a fining tank (18, 1018) of a vacuum induction fining apparatus (10, 1010) and delivering the fined molten glass into a thermal conditioning tank (16, 1016) that is separated from the fining tank by an open space (26, 1026) occupied by an ambient environment (24, 1024). The fining tank includes a vertically-elongated housing (80, 1080) that defines an interior fining chamber (82, 1082) where a bath (76, 1076) of molten glass is collected and maintained. The interior fining chamber is maintained at subatmospheric pressure and the housing is surrounded by at least one induction coil (74, 1074) to introduce heat into the molten glass bath. The vacuum maintained in the interior fining chamber and the heating supplied by the induction coil(s) promote the ascension of gas bubbles upwards through the molten glass bath. A glass-producing system that includes the vacuum induction fining apparatus is also disclosed.