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Glossary Of Furnace Terms

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The roof or crown constructed on a radius for different parts of the furnace.

Back wall (or Gable wall)

The section of wall above the soldier blocks at the furnace charging end.


The mixture of raw materials to a given composition, ready for delivery to the furnace melting end.

Batch Charger

A machine that introduces the batch into the furnace melting end.

Batch House

The building where the raw materials are delivered, stored, handled, weighed, mixed and transferred to the furnace batch storage hopper.

Brace Bolt (or Jack Bolt)

Steel bolts that apply pressure to the outside face of the constructed furnace refractory structures to act against internal outward pressure.

Bracing Member

Steel members that brace the furnace refractory structure.

Breast wall

The section of sidewall between the soldier block and the crown skewback.


The vertical structural steelwork members positioned adjacent to the outside face of the furnace refractory structures to which refractory supporting steelwork members are fixed.

Burn out (or Thermal clean)

A method of cleaning out deposits blocked in the regenerator checkers (or packings) using heat.

Burner Block

A refractory block with one main aperture through which the fossil fuel burners fire.


The working life of a tank furnace from the start of a new furnace construction to the shut-down of the furnace.


The steelwork case supporting the forehearth sub-structure refractory.


The sub-structure part of the forehearth that carries the molten glass from the distributor (working end) of the furnace to the spout.

Checkers (or Packings)

The refractory pieces installed in the regenerator chamber for the purpose of heat recovery.

Conditioning Zone

The part of the forehearth after the cooling zone(s) where the glass is brought to the required working temperature.

Continuous Tank Furnace

A furnace which produces glass on a continuous basis in which the level of the glass remains relatively constant due to the batch being fed continuously into the furnace, therefore, replacing the glass withdrawn.

Controlled Cool-down

The cool-down of a furnace from working temperature to ambient temperature under controlled conditions.

Cooling Zone

The part of a forehearth adjacent to the refiner (or distributor/working end) and before the conditioning zone.

Cooling Zone

Part of the forehearth superstructure rear and mid sections.

Cross-Fired Furnace

A tank furnace with parallel pairs of ports for fuel and air positioned along the length of the melting end with the burner flames travelling across the width of the glass bath and at right angles to the direction of glass flow.


The roof part of selected furnace areas.


Broken glass that is added to the batch for re-melting.

Distributor (Refiner or Working End)

A section of the Tank Furnace to which glass is delivered from the throat and then directed to the forehearths.


A small vestibule section of the furnace at the batch charging position into which the batch is discharged into the furnace melting end.

Electric Boosting

An auxiliary method of adding heat to the glass of a fossil fuel fired tank furnace, by passing an electric current through the molten glass.

End-Fired Furnace

A tank furnace with the ports situated in the back wall of the melting end and the burner flames travelling in the direction of glass flow.

End-Port Furnace

A tank furnace with the ports for fuel and air situated in the back wall of the melting end.

Factory Cullet (or In-house/Domestic)

Cullet that is obtained from the glass making process within the factory.


A mechanical piece of equipment for the function of delivering glass gobs to the forming machine.

Feeder Connection

The opening in the Refiner (Distributor or Working end) sub-structure wall to receive the channel of the forehearth leading to the feeder.

Feeder Opening

An opening in the Refiner (Distributor or Working end) sub-structure wall through which glass flows into the forehearth and towards the feeder.

Flux-line (or Metal-line)

The level of the molten glass in the furnace.

Flux-Line (or Metal-Line)

The level of the molten glass surface throughout the areas of the Tank Furnace.


The casting cavity in a fused cast Alumina/Zirconia, Silica refractory block.


A section of the Tank Furnace leading from the Refiner (Distributor or Working End) from which glass is conditioned and directed to the feeder forming process.

Foreign Cullet

Cullet produced and obtained from an outside source.


An organic product of fusion that has cooled to a rigid condition without crystallising.

Glass Container

A general term used when describing glass bottles and jars.


An amount of hot glass delivered to the forming machine by the Feeder.


The structural steelwork supporting the furnace bottom areas.

Heat up (or Pre-heat) of a Furnace

The increasing of temperature of a cold furnace to operating temperature under controlled conditions.

Hot End

The glass manufacturing areas applicable to hot glass, i.e. melting end, distributor (or working end) and forehearths.

Hot Spot

The melting end temperature zone of a tank furnace having the highest temperature.

Hot Spot

A thin refractory structure showing a glow condition on the external face caused by internal wear.


The superstructure front sidewall of a furnace melting end port carrying the port crown load.

Mantle Block

A refractory block fitting in the gap between forehearth zones.

Melter (or Melting End)

The chamber of a tank furnace in which the glass batch is melted.


The thermal process by which the glass batch is completely converted into molten glass, free from undissolved batch.

Melting Area

The total glass surface area of the melting end, excluding the doghouse area.

Melting Temperature

The range of furnace temperatures within which glass melting takes place.


Molten glass


An opening through which glass flows, generally referred to when relating to a feeder opening in the bottom of the spout formed by the orifice ring.

Orifice Ring (or Bushing)

The ring that forms the opening through which glass flows in the bottom of the feeder spout.


Placing refractory blocks and/or materials over or within existing refractory structure wear areas while the furnace is in operation.


The opening in a furnace superstructure through which fuel or flame enters or exhaust gases escape.

Port Arch

The roof of a port.

Pull (or Load/Output)

The quantity or weight of glass delivered by a furnace in a given time, usually 24 hours.

Rake Block

The refractory block positioned above the melting end burner block and before the port floor top tile.

Raw Batch

A glass batch without cullet.

Raw Cullet

A total amount of cullet without any glass batch.

Recuperative Furnace

A furnace having a recuperator.


A continuous heat exchanger in which heat is conducted from the products of combustion to incoming combustion air.

Refiner (or Distributor/Working End)

A part of a tank furnace for the purpose of conditioning the glass and directing the glass to the forehearths.


The stage in the glass melting process at which the molten glass is made almost free from undissolved gases.

Regenerative Furnace

A furnace having regenerators.


A cyclic heat interchanger that alternately receives heat from the gaseous products of combustion and transfers heat to the combustion air before combustion.


The process where the direction of fuel, combustion air flow and exhaust gases are reversed.

Rider Arch (or Bearer Arch)

One of a series of arches that support the checkers (or packings) in a regenerator.


A floating layer of unmelted material on the molten glass surface.


An extremely small gaseous inclusion in a glass product.

Sill block

The refractory block above the melting end soldier or sidewall block supporting the burner block assembly.


The refractory pieces at each end of a crown or arch.

Skewback Member

The structural steelwork member supporting the skewback.

Skimmer Block

A refractory block that holds back glass surface impurities, positioned at the forehearth entry and adjacent to the refiner (distributor/working end)


A part of a feeder that carries the orifice, revolving tube, plunger, etc.

Spy Hole (or Peep/Sight hole)

A small opening in the superstructure of a tank furnace or walls of regenerators, recuperator and flues through which observations are made.


Hot air and/or flame exhausted through openings in the furnace superstructure due to positive pressure.


An imperfection/crystalline inclusion in a glass product.

Straight Throat

A throat with the bottom positioned at the same level as the tank furnace melting end bottom.

Sunken Throat

A throat with the bottom positioned below the level of the tank furnace melting end bottom.


The parts of a furnace above the soldier/sidewall blocks.

Tank Block (or Soldier block / Sidewall block)

A refractory block used in the construction of the furnace structure that forms part of the melting end and distributor (working end) bath.

Tank Furnace

A furnace that is constructed from refractory blocks to form a bath in which glass is melted.


The process of draining the furnace of glass under controlled conditions.

Teaser (or Furnaceman)

The worker or operative in direct charge of furnace operations, during glass production.


The submerged channel between the melting end and the refiner (or distributor/working end) through which glass passes.

Throat Cover Block

The top or roof blocks of the throat passage.

Throat Sleeper Block

The side blocks of the throat passage.

Thrust Member

A structural steelwork member supporting the end walls of a refractory structure adjacent to a crown or arch contour.

Tie-Rod (or Tie-Bar)

The steel bar spanning and securing a crown or arch or securing steelwork members at each side of a refractory structure.


A block that is placed above the soldier (or side wall) blocks and beneath the breast walls of the melting end and refiner (or distributor/working end)

Tuckstone Member

The structural steelwork member supporting the tuckstones.

Water Box

A water-cooled metal box applied to the outside face of a refractory block or structure or inserted into the glass to prevent glass flow generally in a refiner (distributor/working end) or forehearth.

Water Cooling Coil

A water-cooled metal coil positioned adjacent to a refractory block or structure to cool the local air flow and/or chill glass seepage from a refractory block or block joint.

Working end

Refer to Refiner description.