AU452004B2 - Improvements in or relating tothe manufacture of flat glass - Google Patents

Description

th i n 2 93517, This invention relates to a float process for the manu- facture of flat glass in which a layer of molten glass is

established on a bath of molten metal, and a buoyant body of

molten glass developed from that layer is advanced in ribbon

form along the bath and is cooled as it is advanced until it

is sufficiently stiffened to be taken unharmed from the bath.

A desired width and thickness of the ribbon of glass can

be produced by control of longitudinally directed tractive

effort applied to the ribbon in conjunction with control of

the viscosity of the advancing ribbon. Transverse forces may be applied to the ribbon, for example to maintain the width of

the ribbon as it is attenuated. Such forces have been applied to the ribbon by mechanical contact with the ribbon, for example

by means of edge rollers engaging the margins of the ribbon.

Mechanical contact with the ribbon is detrimental to the

quality of the margins of the ribbon, and does not apply uni-

form force along the ribbon margins.

It is a main object of the present invention to provide

an improved method and apparatus for manufacturing float glass

in which transversely directed forces are uniformly and

accurately applied to the glass in a precisely controlled

manner by non-mechanical means.

According to the invention a method of manufacturing flat glass in which a body of molten glass is established on a bath

of molten metal and is advanced in ribbon form along the bath,

comprises subjecting the glass to transverse forces uniformly

applied along the margins of the ribbon in the plane of the

glass, by establishing an electric current flow along the margins of the ribbon, subjecting the margins of the ribbon

to the influence of a 452. 0 04

25935/71 the glass, and regulating the manetic field actig through flow to/ magnetic field and the current

acting on the/glass. at a controlled Preferably the glass is delivered of metal to establish a layer rate to the bath of molten in said lateral flow of the glass molten glass on the bath, is a ribbon of glass which layer is permitted to develop are the margins of the ribbon advanced along the bath, electric conductive regions, an provided with electrically is said regions, and each region current is passed along to directed perpendicularly subjected to a magnetic field to cause transversely-directed the plane of the ribbon transverse flow of the glass forces in the glass to affect is developed. on the bath surface as the ribbon which the glass ribbon The transverse forces to of the invention uniformly is subjected are by the method of the margins of the ribbon distributed along the length of the ribbon is thus regulated and the width and thickness with the ribbon. The forces without any mechanical contact to thicken the ribbon or inwardly may act outwardly to thin the ribbon. process molten glass is Customarily in the float molten metal rate on to the bath of poured at a controlled glass on the bath by to establish the body of molten appli- glass on the bath. In one lateral spreading of the material electrically conductive cation of the invention, of the spreading body of is deposited along the margins 1e conduc- flow is established alopg molten glass, current

tive re 1{?rs&.nrv.4ic d, and- sd maigljtic filr is2 0 00 .52* directed through the marg-inis -oFhe glass, whereby the force acting in the plane of the glass is operable to influence the spreading of the glass in said body.

The electrically conductive regions are preferably formed along the margins of the ribbon by feeding woven metal braid on the upper surface of each margin, which braid becomes embedded in the glass surface. In a preferred embodiment of the invention direct current is.-supplied to the regions and the direction of the magnetic field to which each region is subjected is related to the direction of the current in each region so that transversely directed forces act on the margins of the glass to regulate the thickness of the ribbon as it is formed. The magnetic field can be regulated to maintain constant opposed forces acting outwardly on the ribbon, whereby the ribbon of glass is developed with a predeter- mined width and thickness. Not only can the transversely opposed forces operate to widen the downstream end of the layer of molten glass formed on the bath and from which the glass in ribbon form is advanced so as to produce a required thickness of ribbon as that ribbon is formed from the molten glass, but also the constant and opposed outwardly directed forces may be maintained acting on the margins of the ribbon as the ribbon is advanced for some distance down the bath and un- til the ribbon has become sufficiently stiffened to hold its thickness. The temperature of the molten glass in the layer formed on the bath by the controlled pouring ofanmolten

glas.6 edi* 1 i~orte{ *metal Iathia Jefe!Ebt egulated

25 935 1 0 0 in the range 850 C to 950 C and the magnetic field is regu-

lated in relation to the longitudinally directed tractive

force applied to the ultimate ribbon of thin glass produced

in order to develop from the layer of molten glass a ribbon

of glass of thickness in the range 1.5 mm to 3.5 mm. In

particular the production of float glass 2 mm thick is

achieved by the method of the present invention.

The invention also provides apparatus for use in

the manufacture of flat glass on a bath of molten metal com-

prising an elongated tank structure-containing the bath,

means for delivering glass to the bath at a controlled rate

and advancing the glass along the bath, thermal regulators

associated with the bath for ensuring that the glass is ad-

vanced as a buoyant body of molten glass in ribbon form

which is cooled as it is advanced until it is sufficiently

stiffened to be taken from the bath, means for establishing

aa electrically conductive regionsextending along the2glass,

electrodes-mounted in the tank structure so as to contact

said electrically conductivel an electric current

supply/connected to the electrodes, and magnetic means

mounted above the path of travel of said region of the

glass so as to direct a magnetic field through that region

of the glass, whereby forces acting on the glass in the

plane of the glass are generated in said region.

In a preferred embodiment the apparatus includes

temperature regulators at the inlet end of the bath to

regulate the temperature of molten glass arriving on the

bath so that lateral flow of the molten glass takes place

to establish said buoyant body on the bath, and. ocating

member'.mrAuted gbovp the bath*ij th e region WfHee said 4 52 004

2 935F

lateral flow takes place to locate against the .upper surface of the margins of the ribbon molten electroconductive bodies

clinging to the~ocating members, through which bodies electrical

connection is established to the conductive region.

The magnetic means may comprise at least one coil mounted above the path of travel of each margin of the ribbon of glass.

The coil may be connected in series with the electrically conductive region of the glass so that the current flowing along the electrically conductive region of

the glass also flows through the coil associated with that

region.

For producing thin float glass a preferred embodi-

ment of the apparatus includes coils of elongated form mounted in line above the margins of the glass, each coil being

individually connected to an electric current supply and being associated with two locating members with clinging

molten metal bodies located over the path of travel of the

margin of the glass adjacent either end of the coil and making

electrical connection with the marginal stripe underlying that coil, and a separate electric current supply connected

to those locating members.

In another embodiment of the invention for producing thin float glass each conductive marginal region are short-circuited, and linear induction is contacted by two spaced-apart electrodes whicimotors are

452,.004

2, 93 5 71

mounted above each ribbon margin between the electrodes

which motors are directed transversely of the tank structure,' and are each operable to induce electric current flow in

the associated conductive region and thereby engender

transversely-directed stretching

4 52, 004 a 25 9.3 5 i forces acting to thin the glass.

The electrically conductive stripes along the

margins of the glass are preferably constituted by woven

metal braid laid down into the glass surface, and the

apparatus according to the invention may further include,

at either side of the glass delivering means, feeding means

for feeding woven metal braid on to the surface of both

margins of the glass. Preferably each braid feeding means comprises a

guide tube whose outlet is positioned close to the bath

surface and is oriented to lay-down metal braid on to the

glass surface, and means for feeding braid down the guide

tube at a rate commensurate with the rate of advance of the

glass along the bath.

The invention further comprehends thin float glass,

for example float glass 2 mm thick, produced by the method

of the invention.

In order that the invention may be more clearly

understood, some embodiments will now be described, by way

of example, with reference to the accompanying drawings,

in which:-

Figure 1 is a diagrammatic longitudinal sectional view of apparatus according to the

invention for use in manufacturing flat

glass,

Figure 2 is a diagrammatic plan view of part of

the apparatus of Figure 1 with the tank

roof structure removed,

Figure 3 is a plan view illustrating the opera-

**.tTh of th" inren jon onM:iading glass ,g 452,004

25935 71 at the inlet end of the apparatus,

and

Figure 4 is a diagrammatic plan view, similar to Figure 2, of apparatus incorporating

another embodiment of the invention.

Referring to Figure 1 of the drawings, a forehearth 1 of a continuous glass melting furnace is indicated at

and a regulating tweel at 2. The forehearth 1 ends in a 5, one of which spout 3 comprising a lip 4 and side jambs is shown in Figure 1. The lip 4 and side jambs 5 together

constitute a spout of generally rectangular cross-section. The spout 3 is disposed above the floor 6 of an 7 joined elongated tank structure including side.walls floor 6, an together to form an integral structure with the wall 9 end wall 8 at the inlet end of the tank, and an end a at the outlet end of the tank. The tank structure holds at bath of molten metal 10 whose surface level is indicated or of an 11. The bath is, for example, a bath of molten tin bath has a alloy of tin in which tin predominates and the

specific gravity greater than that of the glass. A roof structure is supported over the tank struc-

ture and includes a roof.12, side walls 13 and integral

inlet and outlet end walls 14 and 15. The inlet end wall of the 14 extends downwardly close to the surface 11 16 molten metal 10 to define with that surface an inlet

which is restricted in height and through which molten described below. glass is advanced in ribbon form as will be with The outlet end wall 15 of the roof structure defines 17 the outlet end wall 9 of the tank structure an outlet

through which. he..uAliate rfbbon: of. lass. pouced on the g 4 52, 0 04

0 25.93 5 bath is discharged on to driven conveyor rollers 18 mounted

outside the outlet end of the tank and disposed somewhat

above the level of the top of the end walls 9 of the tank structure so that the ribbon is lifted clear of the wall 9 for discharge through the outlet 17.

The rollers 18 convey the ribbon of glass to an

annealing lehr in well known manner and also apply tractive effort to the ribbon of glass to assist in advancing the ribbon as it glides along the surface of the bath

A forward extension 19 of the roof 12 extends up

to the tweel 2 and forms a chamber with side walls 20 in

which chamber the spout 3 is disposed.

Molten glass 21 is poured on to the bath 10 of molten metal from the spout 3 and the tweel 2 regulates the rate of flow of the molten glass/ a over the spout lip 4. The spout is vertically spaced from the surface 11 of the

bath so that the molten glass 21 has a free fall of a few

inches, exaggerated in Figure 1, to the bath surface. This free fall is such as to ensure the formation of a heel 22

of molten glass behind the glass 21 pouring over the spout,

which heel 22 extends up to the inlet end wall 8 of the tank

structure.

The temperature of the glass is regulated as it is advanced along the bath from the inlet end down to the disch-

arge end by thermal regulators 23 immersed in the bath

and thermal regulators 24 mounted in the headspace 25 which

is defined over the bath by the roof structure. A protective gas is supplied to the headspace through ducts 26 which are

provided at intervals in the roof 12 and which aMr connected by braq~Ire 27 .top :.'hder 28 hiah i 'onnectb.* o a supply 10 4 52.004

2593 5 7 of protective gas. A plenum of protective gas is thus

maintained in the headspace 25, which is a substantially

closed headspace, and there is outward flow of protective

gas through the inlet 16 and the outlet 17.

The temperature of the molten glass is regulated

by the thermal regulators 23 and 24 as the glass is advanced

along the bath so as to ensure that a layer of molten glass

29 is established on the bath, the temperature of the glass

being in the range 90000 to 1000 C in this region. This

layer 29 is advanced along the bath through the inlet 16

and as it is advanced lateral flow of the molten glass occurs

under the influence of surface tension and gravity until

there is developed from the layer 29 a buoyant body of molten

glass which is advanced in ribbon form 30 along the bath.

The width of the tank structure at the surface level 11 of

the.bath is greater than the width of the molten glass ribbon

so that there is no limitation to the initial lateral flow of the molten glass.

The molten glass ribbon is cooled progressively as

it is advanced along the bath so that it reaches the

discharge end of the bath as a ribbon 30 at a temperature of

6500C for example, which is sufficiently stiff to be removed from the bath by the rollers 18 without damage.

The lateral flow of the molten glass layer 29 to

form the ribbon 30 is illustrated in Figure 2 and, according

to the invention the thickness of the resulting glass ribbon

is regulated by regulating the extent of the lateral flow

of the glass layer 29.

In particular a thin glass ribbon is produced by

applying controlled outwardlyr.-irectd horigon[i. forces, 11 -4 52, 004 *o

25.935/71 trarPverse to the direction of advance of the ribbon, to the

margin of the glass as the buoyant body formed from the layer

29 is just assuming advancing ribbon form. These forces are

generated by the interaction of electric currents flowing

longitudinally along the margins of the glass and magnetic

fields directed through the glass so that components of the

resulting interaction force act in the desired outward

direction to thin the body of glass 29 to a desired thickness

in the time during which the glass is subjected to the

outwardly directed forces.

Preferably the magnetic field is directed perpen-

dicularly to the electric current, that is perpendicularly to

the glass surface so that the resulting transverse forces act

outwardly in the plane of the glass to supplement gravitation-

al forces acting to spread the glass and thereby stretch the

glass by a required amount, for example to 2 mm thickness or

even more to produce glass 1.5 mm thick. In order to render the margins of the glass elec-

trically conductive two marginal electrically conductive

stripes 32 are applied to the upper surface of the glass

along the opposite edges thereof. Each stripe 32 is

constituted by woven metal braid, e.g. of tinned copper

wire, which is laid down on to the upper surface of both

margins of the body 29 of molten glass and becomes embedded

in the glass surface.

At each side of the spout 3, feeding means is

provided for feeding the metal braid 32 on to the glass

surface, and each braid feeding means comprises a steel

guide tube 3. of..,lattenad rectangular :crss-section

wipi*le*;tdS Oe. the islq; ;d wil 8 of:flhe tank structure 12 4 5 2, 0 04

25935 71 and ts curved inwardly and downwardly as shown in Figures 1

and 2, to lead the braid 32 smoothly and gently on to the

glass surface.

A gas supply tube 34 is connected to the guide tube as 33 and is connected to a source of the same protective gas is fed into the headspace over the bath, so as to prevent

contaminating gases from entering the headspace through the

tube 33. The braid 32 is supplied from a reel 35 which is

mounted on a shaft 36 which rotates in bearings 37 and is

driven by an electric motor 38. The braid 32 is drawn from

the reel 35 by a pair of driven rollers 39, one of which is

shown, which are driven in synchronism with the drive to the

shaft 36 to predetermine the rate at which the braid is fed

down the guide tube 33. The forward velocity given to the

braid is such that it leaves the inner mouth 40 of the tube

at exactly the speed at which the glass 29 is advancing

forwardly beneath the tube mouth As shown in Figure 2, identical braid feeding

arrangements are shown on both sides of the spout so that

both margins of the body 29 of molten glass are simultaneously

provided with continuous electrically conductive stripes. To establish electrical connection with the conduc-

tive braid 32 pairs of longitudinally spaced-apart locating

electrodes 41 and 42 are positioned at intervals along the

bath above the margins of the glass carrying their stripes

of braid 32. A molten metal body 43 clings to each electrode

41, 42 and makes electrical connection with the marginal brid.2 helow. -pt electrodd. .ach pa, "4 electrodes S 41la. 4 s.J Caeted to'aA.electric curreht supply 44 13 452. 004

S 2 .93 whiclPcan be regulated to control the current passing along

the part of the braid between the electrodes 41 and 42. A

coil 45 of elongated shape, and made up of two complete

turns, overlies the braid, between the electrodes 41 and 42,

and the ends of each coil 45 are connected to a controllable

electric current supply 46 individual to that coil.

Each of the coils 45 is positioned so that the

magnetic field produced by current flow therein is directed

vertically through the underlying margin of the glass. At

the same time current is flowing through the braid beneath

the coil, and the resulting interaction force on the margin

of the glass acts outwardly tending to thin the molten body

29 as the ribbon 30 is formed. The force applied is varied

by individually adjusting the current flow in the braid and in each coil. The direct current supplied to the braid 32 by

the supply 44 may be 20 to 30 amperes at a supply voltage of

to 20 volts. The magnetic field is produced by a higher

current in the coil, e.g. 200 to 350 amperes, supplied by the

supply 46 at 50 volts. Alternating current may be supplied to the conduc-

tive stripes along the margins of the ribbon and in this way

of working the magnetic field operating on each margin is

alternated in synchronism with the current so that the

induced forces acting transversely on the glass are maintain-

ed in the same direction. Conveniently the magnetic field

associated with each conductive margin is produced by current

flow in a coil conductor which is used to provide the correct

current flow in the conductive stripe along the margin of the glass...

i U: e:b. odine UL-atatedA .i i Wgures 1 and 2

14 45 2,004

2. 93 5 71 the advancing the outwardly directed forces are acting on but the molten glass after it has assumed ribbon form, to the influence of the transverse forces is felt nearer so that spout while the body of molten glass is spreading, thickness by the the glass has practically achieved a desired margins and the time the braid 32 is being laid on to its the advancing transverse force is being applied. Thereafter forces along ribbon continues to be subjected to transverse succession of its length as its margins pass beneath the held as the ribbon coils 45. The width of the ribbon is thus to cause the cools so that its edges cannot move inwardly thickness. ribbon to assume a lesser width and a greater to the invention The electromagnetic arrangement according glass is a for applying transverse force to the molten to maintain positively stable system which is self-regulating determined by the margins of the ribbon moving along paths when the coils the disposition of the coils 45. Particularly any tendency define parallel paths for the ribbon margins, trend to "snake" on the for the ribbon to stray by a sideways forces which bath is self-corrected by the electromagnetic

restore each margin to its intended path. body be In this way, not only can the molten glass thickness of the caused to spread to a width such that the or even 1.5 mm, but formed ribbon of glass is as low as 2 mm maintained as also that width and thickness are accurately it is the ribbon is cooled to a temperature at which to the continu- sufficiently stiffened to hold its form, due of the ribbon. ous marginal forces exerted transversely As the ribbon cools, less transverse force is

rven%*loss of:wi t4.;nd th':i dividual necega34rVW: 4 52, 0

25935 P

regulation of the current supplied to each coil and to each length

of the braid permits adjustment as appropriate.

Some attenuation of the glass may be effected by regula-

tion of the tractive force applied to the glass and the viscosity

regime to which the glass is subjected, and the loosely woven nature

of the braid 32 enables some stretching of the advancing glass to

take place, for example to trim the thickness dimension of the glass.

The application of transverse stretching forces may begin

as the body of molten glass is spreading on the bath. For example

as shown in Figure 3, the guide tubes 33 are positioned close to

the spout so as to deposit the woven metal braid 32 on the margins

of the molten glass 29 as it is spreading. The first coils

and contacting electrodes 41 and 42 are positioned above the margins

of the spreading glass 29 so that the lateraflow of thenolten glass

layer 29 is directly augmented by the transverse forces induced at

the margins of the spreading layer of molten glass. Another embodiment of the invention is illustrated in Figure 4, in which the linear induction motor principle is used to

provide the transverse forces on a glass ribbon 30 by electro- magnetic interaction. Elctrically conductive braid 32 is laid on

to the margins of the glass ribbon 30 as in the embodiment pre- viously described with reference to Figures 1 and 2. Fixed linear

induction motors 47 are arranged at intervals along the bath above

the opposite edge regions of the ribbon 30. Pairs of motors 47 as

shown are spaced a short distance above the respective stripes 32,

each of which is contacted by two "wetted" electrodes 49 similar to

Is 4 52, 004

25935 171 the electrodes 41, 42 of the previously described emboiftiliW.

Each stripe 32 is contacted by an electrode 49 upstream of its

pair of motors 47, and by an electrode 49 downstream of its

pair of motors 47, and the electrodes 49 are short-circuited

externally by a lead 48.

The linear induction motors 47 operate in a well known

way to induce currents in the respective stripes 32, these

induced currents interacting with magnetic fields perpendicular

to the plane of the ribbon 30 produced beneath the motors 47

to apply transverse forces to the stripes 32, and therefore,

to the margins of the ribbon

Instead of the wetted electrodes 41, 42 or 49.making

electrical contact with the stripes32, free-running graphite

rollers may be employed. The conductive stripes 32 may be

applied in other ways, for example in the form of carbon or

metal coatings applied as a spray.

Also alternative means for applying magnetic fields in

the region of the conductive stripes 32 may, for example com-

prise pairs of parallel conductors extending longitudinally

and disposed symmetrically above the respective stripes 32.

4 52, 004

S 2. 93 5 r7 THE CLAIMS DEPINING THE INVENTION ARE AS FOLLOWS- 1. A method of manufacturing flat glass in which a body

of molten glass is established on a bath of molten metal and

is advanced in ribbon form along the bath, comprising subject-

ing the glass to transverse forces uniformly applied along

the margins of the ribbon in the plane of the glass, by

establishing an electric current flow along the margins of

the ribbon, subjecting the margins of the ribbon to the

influence of a magnetic field acting through the glass, and

regulating the magnetic field and the current flow to generate

in the glass transverse forces acting on the ribbon of glass.

S18 452. 004

Claims (1)

1. 2. A method according to Claim 1, in which glass is delivered at a controlled rate to the bath of molten metal to establish a layer of molten glass on the bath, lateral flow of the glass in said layer is permitted to develop a ribbon of glass which is advanced along the bath, the margins of the ribbon are provided with electrically conductive regions, an electric current is passed along said regions, and each region is subjected to a magnetic field directed perpendicularly to the plane of the ribbon to cause transversely-directed forces in the glass to affect transverse flow of the glass on the bath surface as the ribbon is developed.

   3. A method according to Claim 1, in which molten glass is poured at a controlled rate on to the bath of molten metal to establish the body of molten glass on the bath by lateral spreading of the glass arriving on the bath, electrically..c 4uat.ve mate;ia: is depositd long the

   452. 004

   93 51 glass, current flow margins of the spreading body of molten so produced, and is established along the conductive regions the margins of the said magnetic field is directed through in the plane of spreading glass, whereby the force acting the spreading of the the glass is operable to influence glass in said body.

   3, in which 4. A method according to Claim 2 or Claim surface of each woven metal braid is fed on to the upper in the glass margin of the ribbon and becomes embedded surface.

   1 to 4, in A method according to any one of Claims and the which direct current is supplied to said regions each region is direction of the magnetic field to which of the current in subjected is so related to the direction forces act on the each region that transversely directed the thickness of the ribbon margins of the glass to regulate as it is formed.

   regulating 6. A method according to Claim 5, including opposed forces acting the magnetic field to maintain constant of glass is outwardly on the ribbon, whereby the ribbon and thickness. developed with a predetermined width

   which molten 7. A method according to Claim 5, in metal bath at a controlled glass is poured on to the molten glass in the layer so rate, the temperature of the molten 850 0 C to 9500C, formed on the bath is regulated in the range in relation to longitud- and the magnetic field is regulated to*th:ribbon to inally directed tractive eftrgt applied

   devepfl o i~ade lypr a ribqn of lass of. t4ickness in

   20 4 52, 004 the range 1.5 mm to 3.5 mm.

   93 5 in

   8. Apparatus for use in the manufacture of flat glass on

   a bath of molten metal comprising an elongated tank structure

   containing the bath, means for delivering glass to the bath at a

   controlled rate and advancing the glass along the bath, thermal is regulators associated with the bath for ensuring that the glass advanced as a buoyant body of molten glass in ribbon form which is

   cooled as it is advanced until it is sufficiently stiffened to be

   taken from the bath, means for establishing an electrically con- ductive regions extending along the margins of the ribbon of glass,

   electrodes mounted in the tank structure so as to contact said

   electrically conductive marginal regions, an electric current supply

   connected to the electrodes, and magnetic means mounted above the

   path of travel of said region of the glass so as to direct a mag-? netic field through that region of the glass, whereby forces act-

   ing on the glass in the plane of the glass are generated in said region.

   9. Apparatus according to Claim 8, including temperature

   regulators at the inlet end of the bath to regulate the temperature of the molten glass arriving on the bath so that lateral flow of

   the molten glass takes place to establish said buoyant body on the bath, and locating members mounted above the bath in the

   region where said lateral flow takes place to locate against the

   upper surface of the margins of the ribbon molten metal bodies

   clinging to the locating members, through which bodies electrical

   connection is established to the conductive region. Apparatus according to Claim 8or Claim 9, wherein the

   4 52,.004

   935/7

   magnetic means comprise at least one coil mounted above the path

   of travel of each margin of glass.

   11. Apparatus according to Claim 10, including coils of elongated form mounted in line above the margins of the glass,

   each coil being individually connected to an electric current

   supply and being associated with two locating members with cling-

   ing molten metal bodies located over the path of travel of the

   margin of the glass adjacent either end of the coil and making electrical connection with the marginal stripe underlying that

   coil, and a separate electric current supply connected to those

   locating members.

   22 4 52, 004

   25935/71 12. Apparatus according to Claim 8 or Claim 9, wherein

   each conductive marginal region is contacted by two spaced

   apart electrodes which are short-circuited, andX

   induction A mounted above each( margin between

   the electrodes, which motors are directed transversely of

   the tank structure and are each operable to induce electric

   current flow in the associated conductive region and thereby to engender transversely-directed stretching forces acting

   thin the glass.

   13. Apparatus according to any one of Claims 8 to 12, including at either side of the glass delivering means, V feeding means for feeding metal braid on to the surface of both margins of the glass.

   14. Apparatus according to Claim 13, wherein each braid feeding means comprises a guide tube whose outlet is positioned

   close to the bath surface and is oriented to lay-down metal braid on to the glass, and means for feeding braid down the guide tube at a rate commensurate with the rate of advance of the glass along the bath.

   4 52 004

   93 571 A float glass manufacturing method substantially as herein described with reference to Figures 1 and 2, or Figure 3 or Figure 4 of the accompanying drawings.

   16. Thin float glass produced by a method according to any one of Claims 1 to 7 or Claim

   17. Float glass manufacturing apparatus constructed and arranged to operate substantially as herein described with reference to Figures 1 and 2, or Figure 3, or Figure 4 of the accompanying drawings.

   DATED this 21st day of May, 1971.

   PILKINGTON BROTHERS LIMITED

   By their Patent Attorneys, ARTHUR S. CAVE CO.

   K--

   452, 004

   93 5 71

   4 5t. 0 04

   25.93571

   93 5171

   4 52, 004

   2,50,3571

   452. 004