CONTAINER GLASS FEEDERS :RECENT DEVELOPMENTS

IN THE CHOICE OF REFRACTORY MATERIALS

AFGM Edsa Shangri-la MANILA

SEPTEMBER 21, 2006

It is clearly understood that feeders play a crucial role

in the quality of glass produced by the furnace.

Any defects generated in the feeder zones could well

be found in the finished product, since the glass at this

stage works at relatively low temperatures and has a low capacity

to absorb any flaws.

In addition, market demands for quality are constantly on the

increase. Defects and flaws which were acceptable in the recent

past are now often cause for rejecting the glass. This jeopardizes

both yield and profitability of glass production.

Regardless of the design used to channel the glass from the

distributor to the machines,and to condition it thermally for forming,the choice of the refractories in glass contact is increasingly important.

SAINT-GOBAIN SEFPRO

GLASS CONTACT PRODUCT RANGE

Product Range AZS

Brand name ER 1681 RN ZA 33

Type of product Fused cast Bonded

Chemical analysis % Al2O3

ZrO2

50.9

32.5

75.5

10.5

Physical characteristics Bulk density

Open porosity %

Expansion at 1000 °C (%)

3.5

2

0.9

3.0

16

0.7

Glass quality Bubbling index 1100 °C-1h (0-10)

Stoning index 1250 °C- 36h (0-5)

AZS cat scratches

Corrosion resistance

(MGR – 72 h – 1350 °C)

1-2

0-1

+

100

1-2

1-2

+

80

Product range Alumina

Brand name JARGAL M SCIMOS M

BPAL ARKAL 60 PR

Type of product Fused cast Bonded Bonded

Chemical analysis % Al2O3

ZrO2

95.0

-

93.0

-

68.0

-

Physical characteristics

Bulk density

Open porosity %

Expansion at 1000 °C (%)

3.17

3

0.75

3.10

14

0.80

2.57

15

0.52

Glass quality Bubbling index 1100 °C-1h (0-10)

Stoning index 1250 °C-36h (0-5)

AZS cat scratches

Corrosion resistance

(MGR – 72 h – 1350 °C)

0-2

0

0

100

1-2

0-1

0

80

4-5

2-3

0

45

Out of these 5 types of products, which one is the best technico-

economical candidate to be used as feeder channel blocks for containers?

ER 1

681

Temperatures in ° Celsius

Corrosionin mm

JARGAL M

1200° 1600°1500°1400°1300°

12

9

6

3

1350°

Corrosion curves as a function of temperature ( PFT test )

BPAL ZA33

These curves show clearly that, for feeder

applications, where temperatures commonly occur

between 1200°C and 1280°C, corrosion resistance

difference between BPAL/ZA33 and fused cast AZS or

Alumina is very low.

For campaigns 8 – 12 years, which is the usual lifetime in containers, no need to use fused cast channel blocks.

What about « CAT SCRATCHES »?

One of the types of flaws most often

encountered in container glass are flaws

known as « cat scratches ».

Market sensitivity to this flaw is constantly

growing, and the flaw affects not only white

and flint glass, but also colored glass.

CAT SCRATCHES : definition

• Vitreous defect,

• Band of fine parallel cords,

• Located at the outside surface of the article,

• Diameter between 5 and 30 µm.

Microprobe analysis are done on the cat scratches section

CAT SCRATCHES: refractory characteristics

Melting / Refining

Throat

Working end

Feeder

Decrease of the glass potential to dissolve defects

Corrosion rate or temperature1550°C1350°C

1200°C

Main characteristic

Corrosion Defect formation potential

Based on several decades of experience in

expert appraisals of glass inclusions, the

research teams at Saint-Gobain SEFPRO

have developed highly precise typology of

these cat scratches.

In 85% of the cases, they are characterized

by the simultaneous presence of significant

amounts of zirconia and alumina.

Research into the ZrO2/Al2O3 ratio, and the

presence of certain elements which clearly show

a fusion origin (V2O5 for example in the case of

fuel-heated furnaces) have helped identify the

origin, which, in 80% to 90% of the cases, is the end

zone of the furnace : distributor and feeders.

This understanding has led many glassmakers to

reduce the use of Zircon-Mullite type materials as

much as possible, and generally speaking to

reduce the use of any material with significant

amounts of zirconia, in their feeders.

As a consequence of these results:

•A good way to significantly decrease AZS cat-scratches is to remove ZrO2 from « cold-end »:

- Working end = JARGAL M / SCIMOS M

- Feeders = BPAL

BPAL channel blocks feasability

TO-DATE :

inside width : 1500 mm60 ’’

bottom/walls thickness : 150 mm6 ’’

lenght : 610 mm18 ’’

inside height : 300 mm12  ’’

Bigger sizes on request.

BPAL references

ABOUT 500 FEEDER LINES SINCE 1990

WORLDWIDE

BPAL

BPAL

BPAL

Baby-food/flint glass/8.5 years campaign

BPAL

Baby-food/flint glass/8.5 years campaign

BPAL

LAST DEVELOPMENT (2005-2006)

ON BONDED ALUMINA FEEDER CHANNEL BLOCKS

HPAL

Even better corrosion resistance vs BPAL

+

Almost no blistering in contact

with extra-white soda-lime glass

New alumina product for feederSEFPRO SEFPRO SEFPRO

BPAL HPAL JARGAL MProduct Sintered Sintered FusedBulk density (gr/cm3) 3.1 3.2 3.17Open Porosity (%) 14 17 3Cold crushing strenght (Mpa) 190 160 200

Chemical analysis Al2O3 93 95 95 SiO2 6 2 0.5

Fe2O3 0.1 0.1 0.1

Corrosion resistance index @ 1300°C - 170h 100 115-120 125

Brand Name

ABOUT BLISTERING

Beside « cat scratches » , market can also be

sensitive to another type of flaw,

particulary for white glass: Blisters.

In the bonded Alumina range of products for

channel blocks one can find differences on

blistering, going more deeply in the

laboratory testing.

Blistering test “Le Pontet”

- 1100°C – 1h : immersed sample in the glass

- Scale : 0-1 (very low blistering) 10 (very high blistering)

-1100°C – 1h, white / flint soda lime glass (Fe2O3 = 1000 ppm) :

No big differentiation

0 2JARGAL M BPAL

HPAL

1

New crucible blistering test

- 1250°C – 30h or more : glass inside crucible, like in the feeder.

- Scale : 10 (low blistering) 100 (high blistering).

- Closer to feeder running conditions (T°, air, …)

- More blistering differences than in “LP” test.

- Need more tests in order to have a large data base

1250°C – 30h – white / flint soda lime glass :

More differentiation

JARGAL MBPAL

high Alumina product

10 20 30 40 50 60 70 80 90 100HPAL

New crucible blistering test

1250°C – 30h – extra-white soda lime glass (Fe2O3 < 300 ppm) :

10 20 30 40 50 60 70 80 90 100

New crucible blistering test

BPALhigh Alumina

product

HPAL

JARGAL M

1100 mm

New alumina product for feeder

HPAL

First two orders to be delivered end 2006

NEW PRODUCTS IN THE FIELD OF EXPENDABLES

Spouts with Zirchrom 85 inserts

ZA33 LB : Low seeding after starting up

ZA33HR : Higher thermal shock resistance

to prevent fracturation

SPOUT with ZIRCHROM 85 insert

ZA 33 (11 % ZrO2) or

ZIRAL 61 (19 % ZrO2)

Patented high chrome product (83,5 % Cr2O3) with better thermal shock resistance than any other

More than 3 times the life of monolithic spouts

Case story 1

- Cascade bowl ZA 33/ZIRCHROM 85 insert

- soda-lime glass CHR

- spout temperature : 1225° C

- average pull : 80/100 T pd

- average ring changes : every 8 weeks

- spout change : 8 hours, glass to glass

- Service life : 26 months (furnace repair)

- ZA33/F.C insert life (average) : about 12 months 

Spouts with bonded chrome insert (ZIRCHROM 85)

Spouts with bonded chrome insert (ZIRCHROM 85)

Case story 2

Pre-heating procedure 6 h 6 h 6 h

Daily pull 50 tpd 40 tpd 15 tpd

Gob temperature 1170 °C 1180 °C 1280 °C

Glass flint flint flint

Average job changes/

Months 4 2 7

Service Life 20 to 26 months

ZA 33 mono service life 6 to 8 months

Expendables : ZA33LBReduction of Seeding after starting up and during production

Target : table-ware / flaconnage :

- short runs

- critical problem : mainly with plungers « seeding » during 1 to 10 h or more after starting, whatever the supplier

production losses : 8 to 12 K EUR/hour (EUROPE)

Blistering test for expendables

Test conditions : @ 1250°C, after 30h or with a record of the blistering during the test.

JARGAL M

Refractory sample

Glass

Blistering after 30 hTest conditions : Extra White soda lime glass, @ 1250°C – 30h

-333 : seeding during the starting hours (>30h within conditions of the present test)

-ZA33 LB : Lower blistering, decreasing with time

333 ZA33 LB

Product Blistering Index Observations333 8 Strong blistering on all the surfaces

ZA33 LB 1 to 4Low surface blistering on the bottom : Index 1

Which increase going on the top : Index 4

blisters

Index 1

Index 4

EXPENDABLES : new product ZA33

Tubes fracturation during production worldwide problem with any type of tube from any supplier :

- breakage during heating-up

- breakage after 1,2,3 … weeks of production

- breakage frequency unpredictable

difficulties to differentiate products (333, ZIRAL 61, competition) with standard thermal shock tests (USA thermal shocks test)

a specific test has been developed by R & D in order to differentiate products

A new thermal shock testing method

MethodologyOur methodology is based on the study of the impact of the thermal shock on the mechanical properties of the materials.

Samples of the material are first submitted to one or multiple severe thermal shock (rapid heat up to the test temperature followed by a thermal quenching in cold water) and then mechanically characterized (typically flexural strength MOR).

The residual MOR of the material is compared to the original strength of the material, and a characteristic ratio is calculated :

TR (%) = ( MOR before quenching – MOR after quenching ) x 100

MOR before quenching

The lower the ratio, the better the material withstands thermal shocks.

Among a family of materials having the same crystallographic properties, the best material thermal shock wise is the one with the lowest MOR loss ratio and higher residual strength after quenching.

*MOR=Modulus of rupture

Equipment Samples :

120 x 20 x 20 mm bars are sampled and dried in oven @ 110 °C

Procedure :

-Samples are machined, 2 sets of 5 from same bloc

- 5 samples are loaded in the furnace preheated at the test temperature, and soaked for 20 mn

- samples are removed from the furnace and immediately quenched in water

- once cool, samples are dried in an oven

- flexural modulus of rupture are measured at room temperature on both sets of samples

Electrical furnace

Cold Water box for quenching

A new Thermal shock testing method

New product ZA33

Graphe Delta MOR en fonction de la température de trempe

-70

-60

-50

-40

-30

-20

-10

0

10

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300

Température de trempe (°C)

Del

ta M

OR

( %

)

New product

AZS10

Whatever the quenching temperature is, the new product presents always lower MOR losses (and so a better thermal shock resistance).

*MOR=Modulus of Rupture

New product ZA33

Evolution de la perte MOR en fonction du nombre de cycles

-80

-70

-60

-50

-40

-30

-20

-10

0

0 1 2 3 4

Nbre de cycles

Per

te M

OR

(%

) New product

AZS10

This better thermal shock resistance remains available after 1, 2 or 3 shocks.

  THERMAL SHOCK 1250 °C- 20°C

 

 

Standard

 

New

- Saint-Gobain SEFPRO is permanently looking for high

perfomance refractories in partnerships with

customers thank’s to it’s strong R&D, dedicated to

glass industry.

- Saint-Gobain SEFPRO has the largest Research

Center in the world specialising in refractories and

their interactions with different types of glass. 140

engineers and technicians in the R&D use the most

progressive, multidisciplinary technologies.

Saint-Gobain SEFPRO - R & D

Thank you