Improved Process of Manufacturing Sheet Glass and Apparatus therefor.
Year: 1898

page_text: Date of Application, 22nd Dec., 1898-Accepted, 11th Feb., 1899
COMPLETE SPECIFICATION.
Improved Process of Manufacturing Sheet Glass and Apparatus
therefor.
A communication from PAUL THEODOR SIEVERT, of Dresden, in Germany,
Manufacturer..
I, ALFRED JULIUS BOULT, of 111, Hatton Garden, in the County of London,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to a process for manufacturing sheet or plate glass by
compression or rolling between surfaces of soft permeable material which allow
water to pass through, such as paper, wood pulp, asbestos, cellulose etc., as well
as to apparatus for carrying said process into effect.
The invention consists in the arrangement of solid or hollow metal plates and
rollers the surface of which is covered by a soft permeable material, so that glass
still in its plastic mouldable state is brought in contact with said fibrous material.
The invention offers the advantage that glass plates rolled or compressed
between non-cooling fibrous substances become very smooth and transparent and
may be made of a hitherto unattainable thinness.
In the accompanying drawing:
Figure 1 shows a metal plate and metal roller covered with fibrous material.
Figure 2 shows a hollow metal plate and hollow roller provided on the surface
with perforations, both being covered with fibrous material;
Figure 3 shows an inclined hollow metal plate provided with a fibrous covering,
and a series of small rolls supported in a frame;
Figure 4 shows a hollow metal plate with a fibrous covering and a series of
rolls of gradually increasing diameter;
Figure 5 shows two rolls covered with fibrous material serving to roll a mass
of plastic glass into a plate or sheet and deposit it on a plate also covered with
fibrous material;
Figure 6 shows two pairs of rolls the rollers of each pair being arranged at
different distances apart, in combination with a plate, for the same purpose as
in the preceding figure.
In Figure 1 is a solid metal plate on which is placed a thin layer or cover-
ing of fibrous material. The roller is also provided with a fibrous layer d.
When manufacturing glass plates the molten mass of glass or a glass plate which
has been subjected to preliminary rolling or pressing, is placed on the plate a.
In many cases the cool temperature of the metal will be sufficient to prevent
the burning of the fibrous layers bd, more particularly when the metallic parts
covered by them, are hollow so that they may be continually cooled by water,
steam, air, etc. But it is advisable to moisten the fibrous layers bd with water
or other cooling liquid so that at first the liquid is vapourised and at the same
time or after evaporation has stopped, the cooling temperature of the metal sur-
faces comes into play.

page_text: The moistening of the fibrous layers may be conveniently effected by providing
the metal plates and rollers with recesses or hollow spaces e from which passages
or perforations f (Figure 2) extend to the surface on which the fibrous material
is placed, which are thus supplied from within with water or steam for the pur-
pose of moistening the fibrous material. The latter is preferably used in the
shape of a fabric secured to the metal surface a by means of a frame or clamp g.
On the contact of the moist fibrous layers with the glass, air bubbles are often
formed in the glass, and in order to get rid of them there is arranged, according
to this invention, a series of small rollers c supported in a frame and employed
to roll the glass until it loses its plasticity by cooling. Instead of one or two
large rolls as hitherto used, there are in this case 6 to 8 small rolls which are all
simultaneously in contact with the mass or sheet of glass, so that the contact
takes place successively (in point of space) at short distances apart and the glass
plate is continually worked so that a bubble or blow hole that may be formed
is at once destroyed by the next roll until the glass is cooled to such an extent
that no more bubbles can be produced. It is in some cases advantageous to
arrange the metal plates used as a rolling table in an inclined position, shown
in Figure 3, so as to cause the glass to press against the rolls by the influence of
its own weight.
As shown in Figure 4, the rolls combined in the frame h may be arranged in
a gradually decreasing distance from the roll surface, either by arranging rolls
of the same diameter in an inclined plane in the frame or by placing rolls of
gradually increasing diameter in one parallel plane. In this way the mass of
glass placed on the table is gradually rolled thinner and thinner, and only the
last roll produces a smooth and perfect glass plate of a much smaller thickness
than has been possible hitherto.
In all the cases described in which the working is effected by means of a plate
and rolls, it is advisable to pour out the hot molten mass of glass first on a bare
metal plate adjoining that covered with fibrous material and then to roll it over
on to the latter. In this way the glass slightly cools before reaching the fibrous
material which is thus protected from injury.
The process in itself wellknown--of pouring glass between two rotating rolls
(Figure 5) which roll it into a plate and deposit on a plate a¹, may be also
employed. The rolls c¹ as well as the plate a are also covered with a surface
layer of fibrous material.
Several pairs of rolls c¹ cat different distances apart may be arranged
(Figure 6) in order gradually to roll the glass plate thinner and thinner and to
deliver it on the plate a¹, the glass coming in contact only with the fibrous
layers b b¹
A pair of non-covered metallic rolls may be used over the rolls c¹ covered with
fibrous material so as to cool the glass slightly before allowing it to come in con-
tact with the fibrous surfaces.
Having now particularly described and ascertained the nature of the said in-
vention as communicated to me by my foreign correspondent and in what manner
the same is to be performed, I declare that what claim is:-
1. The process of manufacturing glass plates by pressing OF rolling glass when
in a plastic condition between surfaces covered with a layer of fibrous material
substantially as described.
2. Glass-rolling plates or rolls the surfaces of which are covered with fibrous
material, said plates or rolls being provided with hollow spaces for the purpose
of cooling the fibrous layers substantially as described.
3. Hollow glass-rolling plates or rolls the surfaces of which are covered with
fibrous material, the arrangement of perforations or passages in the plates and
rolls for admitting water or steam for moistening the fibrous material, substan-
tially as described.
4. The combination of solid or hollow perforated plates, covered with fibrous

page_text: .
material with a series of rolls supported one behind another in a frame sub-
stantially as described.
5. The combination of perforated solid or hollow plates covered with fibrous
material, with a series of rolls of different diameters supported one behind another
in a frame substantially as described.
6. The combination of perforated solid or hollow plates covered with fibrous
material with a series of rolls supported one behind the other in an oblique
direction in a frame, the surface of said rolls being covered with fibrous material
substantially as described.
7. The combination of one or more pairs of solid or hollow rolls arranged side
by side, and covered with fibrous material, with a solid or hollow plate the sur-
face of which is covered with fibrous material for the purpose of producing a
glass plate between the pairs of rolls and depositing it on the plate substantially
as described.
8. The combination of plates and rolls the surfaces of which are covered by a
moistened layer of fibrous material, for the purpose of producing glass plates by
pressure or rolling substantially as described.
9. The combination and arrangement of parts constituting means for use in
rolling glass plates substantially as described and illustrated in Figure 1 or in
Figure 2 or in Figure 3 or in Figure 4 of the accompanying drawings with or
without the supplementary covered rollers Figure 5 or Figure 6.
Dated this 14th day of December 1898.
BOULT & WADE,
Agents for the Applicant.