Day Tank
Day Tank from IWG Glasofenbau
The day tank was developed as an independent furnace type to provide a periodically operating melting unit – but without the typical disadvantages of a pot furnace, such as complex pot changes or temperature-related limitations.
Similar to a pot furnace, the melting process follows a 24-hour cycle. In contrast, however, the day tank allows for significantly higher melting temperatures without damaging the melting basin. This makes it suitable even for difficult-to-melt glass types.
Day tanks are primarily used for studio and small-batch glasses. For applications with particularly high quality requirements, the pot furnace still offers advantages, especially due to the separate melting process in individual pots.
The heating of a day tank can be done either electrically or with fossil fuels (gas or oxy-fuel) and can be flexibly adapted to the respective process requirements.
Day Tank
// IWG Glasofenbau
Gas-heated Day Tank
Gas-heated day tanks are among the most commonly used designs in discontinuous glass furnace construction. Heating is typically done via natural gas or LPG burners, which are precisely aimed at the glass bath and the combustion chamber. Direct combustion allows the required melting temperature to be reached relatively quickly and regulated precisely.
A significant advantage of gas-heated day tanks lies in their high thermal performance combined with simple plant technology. Temperature profiles can be flexibly adapted to different glass recipes, which is particularly relevant for frequent glass changes or varying batch sizes. The design also allows for a compact furnace construction with manageable investment costs.
Gas-heated day tanks are primarily used where process reliability, robust technology, and economical implementation are paramount. Depending on requirements, they can be equipped with different burner systems, refractory materials, and control concepts.
Glassware and Kitchen Glass
Crystal glass, Soda-lime glass,
Lead crystal,
Glass Containers
Soda-lime glass
Type of Glass
Crystal glass, Lead crystal
Colored glass
Conditioning
Forehearth for various glass types
Conditioning
Platinum Feeder System
Electrically Heated Day Tank
Electrically heated day tanks are used when high temperature homogeneity, precise process control, and low emissions are paramount. Heating is done via electrically operated heating elements, which are arranged directly in the furnace chamber or in the immediate vicinity of the glass bath. This allows heat to be introduced into the glass very uniformly.
A key advantage of electrically heated day tanks is the precise controllability of temperature. Fluctuations in the melting process can be minimized, which is particularly important in the production of high-quality technical or optical glass. Furthermore, electrical heating does not produce combustion-related exhaust gases in the furnace chamber, which can positively influence glass quality.
Electric day tanks are particularly suitable for small to medium melting capacities and for applications with high demands on purity and reproducibility. Depending on the operational conditions – especially energy costs – they represent a technically sophisticated alternative to gas-heated systems. IWG Glasofenbau designs electrically heated day tanks individually tailored to the glass type, batch size, and production processes.
Glassware and Kitchen Glass
Crystal glass, Soda-lime glass,
Lead crystal,
Glass Containers
Soda-lime glass
Type of Glass
Crystal glass, Lead crystal
Colored glass
Conditioning
Forehearth for various glass types
Conditioning
Platinum Feeder System
Oxy-Fuel Heated Day Tank
Oxy-fuel-heated day tanks operate with combustion from fuel gas and nearly pure oxygen instead of ambient air. By eliminating the nitrogen content, a significantly higher flame temperature is achieved with a simultaneously reduced exhaust gas volume. The energy introduced thus acts more directly on the glass melt.
A key advantage of oxy-fuel heating lies in its high energy efficiency and very uniform heat distribution. The melting process can be designed more compactly, which is particularly beneficial in cases of limited installation space or special glass formulations. At the same time, CO₂ and NOₓ emissions can be significantly reduced compared to conventionally air-heated systems.
Oxy-fuel-heated day tanks are primarily used for demanding glass types, higher quality requirements, or modernization projects. The technical effort and operating costs for oxygen supply are higher, but these are offset by process stability, energy savings, and improved glass quality in many applications.
Glassware and Kitchen Glass
Crystal glass, soda-lime glass,
lead crystal,
Glass Containers
Soda-lime glass
Type of Glass
Crystal glass, lead crystal
Colored glass
Conditioning
Forehearth for various glass types
Conditioning
Platinum Feeder System
Areas of Application for Day Tanks
Day tanks are used wherever glass is produced not continuously, but in batches and with high flexibility. They are particularly suitable for production processes that require frequent glass changes, small to medium melting volumes, or special glass compositions.
Typical applications include the production of technical glass, special glass, colored glass, and optical glass. Day tanks are also used in development and pilot plants, as they enable precise control of the melting process and good reproducibility of results. Due to their discontinuous operation, formulations can be specifically adjusted without long transition phases or high material losses.
Depending on the glass type, quality requirements, and energy concept, day tanks can be gas-heated, electrically heated, or designed as an oxy-fuel system. IWG Glasofenbau develops day tanks individually for their respective application – from experimental facilities to industrial special glass production.
Technical Features of Day Tanks
The technical equipment of day tanks is individually adapted to the glass type, melting capacity, and mode of operation. Central components are the combustion chamber, the melting tank, and the refractory materials used, which are matched to the respective thermal and chemical stresses. Depending on the glass formulation, different tank materials and lining concepts are used.
The most widespread is a key equipment feature is the respective heating concept. Day tanks can be gas-heated, electrically heated, or designed as an oxy-fuel system. The choice of heating method influences the energy input, temperature distribution in the glass melt, emission behavior, and the controllability of the melting process. In addition, control and regulation systems can be integrated to precisely manage temperature profiles, heating rates, and holding times.
Further equipment features concern the charging of the furnace, the tapping of the molten glass, and safety and monitoring devices. These include manual or automatic charging systems, defined tapping points, and measurement and control technology for process monitoring. IWG Glasofenbau designs day tanks modularly, so that the technical equipment can be precisely adapted to the respective production requirements.
Advantages and Limitations of Day Tanks
The advantages and limitations of day tanks arise directly from their discontinuous mode of operation and from the typical requirements for flexible glass production processes.
Advantages of Day Tanks
- High flexibility in glass recipes and batch sizes
- Suitable for frequent glass changes and special glasses
- Good process control through discontinuous operation
- Compact design with low space requirements
- Comparatively manageable investment costs
- Precise temperature control possible depending on the heating concept
- Well applicable in development, pilot, and special applications
Limitations of Day Tanks
- Limited melting capacity compared to continuous glass melting furnaces
- Not suitable for high-volume mass production
- Higher specific energy costs per ton of glass
- Repeated heating and cooling phases required
- Partially higher personnel monitoring and operating effort
- Economic efficiency highly dependent on application profile and energy costs
Whether a day tank is the suitable solution therefore largely depends on the desired production volume, the type of glass, and the operational conditions.
Service Life, Campaign Operation, Modernization and Retrofitting
Day tanks are usually operated in campaigns. The duration of a campaign is largely determined by the type of glass, operating temperature, chemical load, and the refractory materials used. Compared to continuously operated glass melting furnaces, the service life of day tanks is generally shorter, but downtimes, overhauls, and modifications are technically easier to plan.
An advantage of this operating principle is the good accessibility of the system. Refractory linings, heating components, and control technology can be specifically renewed or adapted during campaign changes. This allows day tanks to be modernized relatively flexibly without requiring extensive structural interventions in the overall system.
Retrofits, for example in the area of heating, measurement and control technology, or emission reduction, are also easily implementable for day tanks. This enables a gradual adaptation to changed production requirements, new glass recipes, or stricter energy and environmental regulations.
IWG Glasofenbau already considers campaign operation in the design to ensure ease of maintenance and long-term operational reliability.
Day Tanks from IWG Glasofenbau
In the design of glass tanks, profound process understanding and practical experience are crucial. IWG Glasofenbau has many years of expertise in the planning, design, and implementation of day tanks for various glass types and production requirements. The heating method, tank construction, refractory materials, and control concepts are specifically tailored to the respective melting process.
Whether it\'s the new construction of a glass tank, adaptation of existing systems, or technical retrofitting – IWG accompanies projects from conceptual planning to implementation during ongoing operation. The goal is a glass tank that operates reliably, is economically designed, and meets the requirements for quality, flexibility, and service life.
Glass furnace construction – then IWG.