Glass Processing+ Forming

-Non continuous process-Continuous Melting

Studiofurnace 2004

Small melting unit in venice based on 60 years old technology

Melting furnace according to Agricola (16.Jhr.)

Non continuous: Pot furnace

Edinburgh, University, Art Glass Department (2001)

Studio furnace Corning, Steuben Glass Factory (2001)

Temperature profile and melting phases of a pot furnace

Continuous flow glass-processing(Tank furnace )

Glass melting furnaces with regenerator: - end port- side port

bubblers

electrodeselectrode

flames

feeder

pull

deep refinershallow finer

fossile fuel melter

internal

batch

pre-heater

batch

melter

1350 C1600 C 1200 C

1300 C1200 C

1500 C

1000 C

bubblers

batch batch melting quartz primary fining refining conditioning

pre-heating dissolution

Forming Process

Pot furnace forming

Free form- by lamp, torch

Casting - used primarily for production of art glasses and/or lenses.

Blowing Hollow ware, bottles etc

Pressing - Hollow ware , jar, wide mount objects

Floating, Drawing For sheet glass , plate glass "float bath" is a furnace containing molten tin.

Forming process

casting

The most important methods:

blow-blow process press-blow process

Double gob shear mechanism

The gob of molten glass falls into the inverted parison (pre-container) blank mould, It is blown down into the mould back up into the now closed mould.

The inverted parison is transferred to an upright posi-tion in the blow mould where it is reheated

During blowing, a vacuum is applied through the mould to suck any trapped air or other gases from the bottom of the mould.

Blow and blow process

IS Machine, blow and blow-procedure

Melting and Forming

1) parison mould 3) finish (blow) mould

2) delivery leverpress - blow

Flat glass forming:

Forming flat glass by- Fourcault process- Colburn-Libbey-Owens process- Down draw process- Boudin process- Float process

canal

canal coolers

drawing

tower

kiln

debiteuse

depressor

mechanism

Fourcault flat glass updraw process

Colburn Libbey-Owens flat glass drawing process

immersed skim bar

bending roll lehr rollers

single-piece

refractory bowl

bowl chamber,

heated by gas

or electricity

muffle

tube sheet coolers

edge rolls

onion

draw-down process

(Vello)

cone

onion

glass tube

muffle

orifice

bell

Melting and Forming Corning fusion downdrawing process

sheet drawn downward

homogeneous glass

delivered from

melting unit

root

trough

Float Process

Float glass side port tank furnace

regenerator

Slightly reducing by Injection mixture N2 and H2

liquid Sn

N2-H2 gas mixtureheaters

1050 C

600 Cspout

falling film

floating & drawing

flow through a notch

Floating is just only one out of many hydrodynamic principles

applied in the float glass process.

Conclusions

Surface tension , gravity Cross-fired regenerative tank furnace Atm nitrogen and hydrogen tin= 6.5, glass =2.6 g/cc

Melting and Forming

Melting and Forming

Tube glass forming

Forming glass tube, glass rod by- Danner process- Updraw process- Down draw process- Vello process

Danner process

Melting and Forming

textile fibre drawing (small orifice)

Melting and Forming

insulation fibre production

raw material silos

melting tank

fibrization unit

uncured woolbinder spray

binder curing oven

chopper

product

Annealing process: "

Definition: * to prevent or remove stresses in glassware by controlling cooling from a suitable temperature

*A controlled cooling process for glass designed to reducethermal residue stress to a commercially acceptable level.

The annealing temperature and the cooling rates must be computed correctly. Thickness of glass is the very important parameter.

Methods to determine annealing temperature

1. Dilatometry

2. Differential scanning calorimetry

3. Differntial thermal analysis

Stress release Annealing Cooling

Deformation pt

Tg+30

Transformation pt

Annealing temp=Tg+10

Lower annealing limit= Tg-100

ICG Annual Meeting 20157-10 September 2015: BANGKOK, THAILAND

AOCCN 2015 BANGKOK, THAILAND