Improvements in or connected with Casting Tables for Glass and Glass Making.
Year: 1892

page_text: Date of Application, 27th Apr., 1392-Accepted, 28th May, 1892
COMPLETE SPECIFICATION.
Improvements in or connected with Casting Tables for Glass and
Glass Making.
I, HENRY CLAY BULL, of 7, Waterloo Road, New Brighton, in the County
of Chester, Engineer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :—
This invention has reference to the manufacture of plate glass and to casting
tables onto which glass is poured and cast into plates; and it has for its object,
amongst other things, to cast such plates in such a manner that they will require
less grinding or treating than those produced by the present process and construction
of table, to bring them to an even or smooth surface; and hence by the invention,
the production or manufacture of plate glass is rendered more rapid and propor
tionately less costly.
According to this invention, a casting table is constructed of a plurality of blocks
or pieces of metal (such as cast iron) having between them a small space, the
blocks being kept apart by a suitable means, such as hereinafter specified; and
the whole set of blocks are kept in place by a frame hereinafter called the
"forme."
That the invention may be fully and clearly understood I have hereto annexed
drawings illustrative of it, and these I will now describe. It is, however, to be
understood that the particular construction and combination of parts shewn in the
drawings is given as a suitable one, and as an example only; and therefore it is to
be stated here, and understood, that the invention is in no way confined or limited
to this particular example, or to the form or construction or combination of its
different parts.
In the drawings,
Figure 1 is an elevation partly in section of the said example of casting table
according to the invention; whilst Figure 2 is a plan of same.
Figure 3 is a sectional elevation shewing in detail an example of special con-
struction of the blocks; and Figure 4 is a plan of same.
With reference to the drawings; a designates the blocks of which the casting.
surface of the table is composed; bare strips of asbestos board, or other suitable
material, by which the blocks are kept a certain distance apart; c is the forme by
which the blocks are beld or kept in place; d are bars arranged at the sides and
ends of the table, and kept up to the blocks by the forme e through wedges e and
pins e', said pins being forced up to the bars d by the wedges; f is the bed plate
supporting the blocks a and their forme, and is the gauge plate by which
the thickness of the plate produced is gauged and regulated as in the ordinary
table.
With reference to the details shewn in Figures 1 and 2, i are air or other fluid
inlets through the bottom of the table, and are outlets for same, the said
inlets being disposed in the cavities a¹ in the blocks_a. By these means, a
circulation of air or other suitable fluid can be maintained within the blocks, and
the blocks prevented from becoming overheated or retained at any desired
temperature, and expansion kept as small as possible. This circulation may be
effected by artificial means or naturally.
The blocks a are all of the same height, and the surface of the table formed by
them is even throughout.
The action and effect of the above construction of table according to this
invention is as follows:-When molten glass is run or cast onto the table (this
being done in the usual way,) the metal of the upper and free ends of the blocks a,

page_text: expands, but since the blocks are maintained or retained within the forme e, which
is not heated, a small portion only of the expansion of said blocks is imparted to
or takes place in the table as a whole, but each block expands within itself and
with little or no appreciable warping, and what little expansion does take place at
the lower part of the blocks where they are held, it is taken up by the dividing
strips b, which run across each other as shewn, and they become compressed.
Hence the table or surface on which the glass is cast does not expand appreciably
as a whole, and the parts of which it is made, do not affect each other, but the
expansion is confined entirely to, and is divided up into or distributed over the total
number of blocks of which it is made; the effect of which is, that the irregularities
which occur in glass made by or on ordinary casting tables are, by this invention,
almost, if not entirely, avoided, and the time and the cost of their removal is
saved.
The distance apart of the blocks a may be under a 32nd of an inch, and the
means by which they are bound together, yet separated or kept apart, at their
upper part may be applied to them or form part of them. When made in strips,
it may in some cases, consist of rigid metallic strips. In cases in which the
bases of the blocks are rigidly held, it will be advisable to employ strong springs
or spring washers between the blocks and their containing forme, so as to provide
for a small amount of expansion of the table; whereas this may not be necessary
(although it may be used) when expansion of the lower part of the blocks is
separated by asbestos or other suitable material having elasticity. However when
the rigid arrangement of blocks is employed, the cooling of or otherwise keeping
at a requisite temperature artificially, the lower parts of the blocks where they
come in contact with each other, directly or indirectly, will in most cases allow of
the expansive and contractive actions of the upper and free ends of the blocks, due
to the effect of the molten glass upon them, to take place with little or no effect
upon the lower and fixed parts.
Plates by or on the ordinary casting table in most cases require as much as from
two fifths to half of their thickness subsequently ground away, before they are
brought to an even surface. It will thus evidently be seen, that an enormous waste
of time and labor, and consequently large expenditure of money, must necessarily
take place in producing plate glass by the ordinary process and casting table,
whereas by my invention, due to the large reduction of the irregularities of the
plate produced a very considerable part of time, labor, and expense, in reducing or
grinding the plate to an even surface can be saved.
A glass plate so produced may be taken from the table and placed in an ordinary
or other suitable annealing or reheating furnace and subjected on one or both
surfaces to a rubbing action by suitable wooden instruments (especially weighted
or pressed upon if desired) whereby the small irregularities of the glass, which by
my invention are produced, are removed, and the plate rendered smooth, even, and
clear, and practically a "finished "plate for many uses or applications.
Some of the blocks a may be bolted down to the base f, if desired, for the
purpose of preventing their displacement by uneven expansion.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1
1. Casting tables for glass substantially as herein set forth, that is to tables
say,
composed of or comprising a plurality of pieces or blocks suitably held in place,
and having their upper ends free or separated from each other.
2. A casting table for glass, comprising a plurality of blocks retained by or
within a suitable forme, and separated or free at their upper ends and having
between them at their lower parts, distance pieces or strips, or pieces of suitable
material; substantially as and for the purposes set forth.
3. A casting table for glass, consisting of a plurality of blocks, substantially as
described, the lower parts of said blocks being adapted to be maintained at a

page_text: desired temperature, or cooled by having a fluid circulated or passed through them;
for the purposes set forth.
4. The manufacture of smooth and even plate glass by casting molten glass into
plates, and subsequently heating and flattening or smoothing same; substantially
as herein set forth.
5. A casting table for glass, having its parts constructed and arranged and
adapted to operate substantially as set forth with reference to the drawings.
Dated this 26th day of April 1892.
CHEESBROUGH & ROYSTON, Fels. Chart. Inst. P.A.,
15, Water Street, Liverpool, Applicant's Patent Agents.