Furnace equipments products



Electric boosting has been used for many years in the glass industry, initially most boosters were installed simply to increase furnace output. Today electric boosting can be utilised to give a number of benefits including:


Each booster system is tailor made according to the furnace type and the customers requirements. Glass Service has developed their boosting system technology and can offer systems as follows:


Each booster system supply by Glass Service can be supplied as a stand alone system or integrated into the furnace control system. Glass Service can supply all of the equipment required for the electric booster including:



Melting Booster

Increasing furnaces output

Reducing emissions

Improve glass quality

Increase furnace output flexibility

Recommended for coloured glass (green, amber, etc.)

Retrofit installation possible in operating furnace

When installed to increase the furnace output, the booster can normally provide an additional 30% over and above the glass melted by the fossil fuel firing. Note that electric boosters are recommended in colour glass furnaces (green, amber, etc.) to maintain bottom temperature.

The melting booster electrodes can be installed in the furnace side walls or in the furnace bottom, however bottom electrodes are preferred to minimise corrosion of the side wall blocks.

The majority of boosters (depending upon furnace geometry), have an installed power in the range of 400 to 1200 kVA although much larger systems are not uncommon when the cost of electricity is attractive.

Transformer Technology

The power transformer technology used depends on the size of the installation. For smaller installations:

For larger installations:

With the exception of throat boosters which are usually single phase, the majority of installations are three phase and are designed to give a balanced load on the three phases. Each system is individually designed to suit the customers requirements, the installed power of the booster being calculated to provide the required increase in output (or other parameter), taking into consideration the furnace design, glass composition / colour, furnace bottom temperatures, electrode current density, etc.

Thermal Barrier Booster

Increasing furnace output

Reducing emissions

Improve glass quality

Increase furnace output flexibility

Improve the convection current at the hot spot

Retrofit installation possible in operating furnace

Although the barrier booster provides additional energy which can increase output, the main purpose of this type of booster is to reinforce and fix the convection current in the furnace at the hot spot and to increase the temperature in the front zone of the furnace.

The improved convection current creates a barrier to the batch resulting in better batch cover and an increase in glass quality. It is recommended for soda lime glass and for deeper furnaces. The installed power can vary from 200 to 1000 kVA depending upon furnace size and geometry. The driver technology is usually thyristors &-dry-transformer. In some cases, for higher power the tap position changer can also be used. The connection is usually three phase and the electrodes are positioned to give a balanced load on all three phases.

The electrodes are molybdenum rods with water cooled electrode holders. The barrier booster power is limited by the furnace bottom temperature, glass temperature and electrode temperature.

Throat Booster

The throat booster is used for heating up of the furnace’s throat or temperature maintenance. It is recommended for deep refiner furnace, coloured and special glasses.
The power installed is usually in the range 30-70 kVA.

The driver technology is thyristor and dry-transformer low voltage drive single phase (e.g. 400 Vac).
The electrodes are molybdenum with water cooled electrode holders.

Circuit type on load
tap position changer transformer

The use on load tap changer transformer technology OLTC has been developed by Glass Service and is a very powerful and reliable transformer technology.

The OLTC is the most used technology in all the electrical power stations for voltage adjustment.
The voltage is regulated by step with no energy disconnection.

The OLTC transformers used by Glass Service have the following features:

The OLTC transformer has several advantages:

Circuit Type Thyristor Unit

The thyristor unit TU is used for low power boosters in the range of 30-400 kVA, this system is considerabily cheaper to instal than OLTC. The thyristor drive technology developed by Glass Service has increased energy savings and safety levels. The TU comprises a Thyristor unit control cabinet and one or more dry transformers. The power is regulated by phase angle control.

The TU develop from Glass Service has the following features:

Control System

Glass Service has developed a special control system dedicated to booster technology. The system is based on DCS Honeywell HC900 and is able to manage the Tap position changer booster OLTC or the thyristor TU booster. Control system is able to manage:

The HMI could dedicate by local touch screen panel or central PC SCADA. Al the process parameters and variables are controlled and recorded in the control system for process analysis.

Water Cooling

Each booster has a dedicated water cooling circuit to provide cooling water to the electrode holders using a special flow control and monitoring system designed by Glass Service.

The water flow is manually controlled and in the event of low water flow any increase in temperature is detected by a temperature sensor. In addition any pressure drop is detected by a pressure switch. The water flow switch is highly reliable and very simple to maintain.

Electrode Holders

Strong mechanical construction, one piece head

Double cooling circuit water + air

Air cooling circuit for easy hot installation

Horizontal or vertical installation

Full accessories including supports, connectors, etc.

Glass Service has developed a new high reliable electrode holder for use with molybdenum electrodes. The holder has a dual cooling circuit, the main circuit being for water and the secondary circuit for emergency air to be used in the event of a water cooling fault and also during the initial electrode installation.

The electrode holder is manufactured from a special alloy with resistance to high temperatures. The head is produced from a single piece, machined and welded using laser technology.

Holders are supplied for use with a range of electrode diameters including 1.50, 2.0, 3.0 and 4.0 inch.

Main electrode holder features:

The electrode holder can be equipped with several installation accessories: