AN IMPROVED MANUFACTURE OF TOUGHENED OPAL GLASS ARTICLES AND APPARATUS THEREFOR
Year: 1884

page_text: PROVISIONAL SPECIFICATION.
I, CHARLES DENTON ABEL of N° 28 Southampton Buildings, Chancery Lane
in the county of Middlesex, Consulting Engineer and Patent Agent, do hereby
declare the nature of my invention for if AN IMPROVED MANUFACTURE OF
TOUGHENED OPAL GLASS ARTICLES AND APPARATUS THEREFOR to be as
follows:-
נן
In order to enable the glass toughening process (which consists in plunging the
heated glass into a heated liquid bath) to be applied in the manufacture of articles
for tablo service, it is necessary that opal glass should be employed, in order that
it may resemble porcelain as much as possible.
But as the toughening process is not readily applicable to opal glass, the manu-
facture is according to the present invention carried out as follows.
The article is, in the first instance, formed of opal glass, made as thin as
practicable, and this is then coated in any known manner, either on one face, or
preferably on both faces with one or with two layers of ordinary glass or crystal
glass and the articles thus formed of a combination of opal and transparent glass will
then readily lend themselves to the toughening process, which may then be carried
out in the ordinary manner, but which is by preference conducted as follows. The
glass article after being formed is first heated in the mouth of the glass furnace
and it is then subjected to pressure in moulds in order to give it the exact configu-
ration required, after which it is heated in a rebeating furnace. This consists by
preference of a muffle or chamber heated externally by a fire, and having two
working openings, in front of each of which, within the muffle, are a number of
moulds, there being two such to each article to be heated, one corresponding to the
face of the article (such as a plate) and the other to the back.
The article is first placed, say, with its face on the one mould, so that its back is
submitted to the direct heat of the muffle, and when heated, to the requisite degree,
it is placed on the other mould, which has meanwhile become heated to the same
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page_text: degree and its face is then also submitted to the direct heat of the muffle, so that
both sides of the article become uniformly heated, whereupon it is removed and
plunged into the tempering bath. While the above operation has been performed,
another batch of glass articles has been brought to the other opening of the furnace,
to be treated in the same way as above described, and thus the workman who
attends to the tempering or toughening process passes alternately from the one
opening to the other to remove the reheated articles.
The opal glass may, before being coated with the other glass, be ornamented
with raised or colored designs in any desired known manner.
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: I, CHARLES DENTON ABEL, of No 28 Southampton Buildings, Chancery Lano
in the county of Middlesex, Consulting Engineer and Patent Agent, do hereby
declare the nature of my invention for "AN IMPROVED MANUFACTURE OF
TOUGHENED OPAL GLASS ARTICLES AND APPARATUS THEREFOR
"and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement:—
In order to enable the glass toughening process (which consists in plunging the
heated glass into a heated liquid bath) to be applied in the manufacture of articles
for table service, it is necessary that opal glass should be employed, in order that
it may resemble porcelain as much as possible. But as the toughening process is
not readily applicable to opal glass, the manufacture is according to the present
invention, carried out as follows:-
The article is in the first instance formed of opal glass, made as thin as practicable,
and this is then coated in any known manner, either on one face, or, preferably, on
both faces with one or with two layers of ordinary glass or crystal glass, and the
articles thus formed of a combination of opal and transparent glass will then
readily lend themselves to the toughen process, which may then be carried out in
the ordinary manner; but which is by preference conducted as will be presently
described. By this means a plate is obtained having the opaque nature of opal
glass and being, consequently, very similar to porcelain, but which is provided
with an external coating of toughened glass or crystal so that the internal mass of
opal glass is not in any way injuriously affected by the toughening process in
consequence of the protecting coating. Objects constructed in this manner will
effectually resist violent shocks and the action of hot water and even fire and they
are not liable to become chipped at the edges. It will be evident that this process
can be applied to the manufacture of vessels ornamented in any desired manner.
The opal glass can be colored, gilded or coated with either metals of any desired
colors, or designs or flowers may be painted thereon with vitrious colors. Also
designs painted on asbestos cloth may be applied thereto, or they may be enamelled
in any colours. The surfaces so prepared being in all cases protected by the coating
of toughened glass or crystal and being thus preserved from deterioration, they
are of a very durable nature. For toughening plates, constructed as described, in
the most effectual manner, they are reheated to a high degree in the opening of the
melting furnace. They are then placed upon a mould fixed underneath a press
and they are pressed in order to impart to them the exact configuration required.
The plate is then taken to the reheating furnace; the opal glass is subjected with
greater difficulty to the reheating process than the ordinary glass, on account of
the radiation caused by its color. In the opening of the melting furnace, its
surfaces become heated too quickly to allow the body thereof to become heated
to the same temperature. This is not the case when a special reheating furnace is
used which is only raised to the required temperature and in which the object can

page_text: .
remain any desired length of time for becoming uniformly heated without risk of
becoming deformed or of adhering to the mould. The rehoating furnace can be
constructed in various ways, the construction employed by preference is shewn on
the accompanying drawing in vertical section at Fig. 1. It consists of a fire-
grate A the flames from which pass through the flues B to the chimney C; 00 are
the working openings. Within the furnace are moulds of fire clay having the exact
configuration of the plates. Two moulds are required for each plate, one for each
surface thereof, namely a mould as shewn at Fig. 2 for the underside and a second
mould as shewn at Fig. 3 having the configuration of the upper side. The furnace
always contains at least two moulds of each kind in front of each working opening.
These moulds are only taken out of the furnace for being placed upon the slab in
front of the working opening during the time necessary to place thereon the plate
to be treated. The operator is situated in front of one of the openings, and operates
upon the plates which he has in front of him, while a boy introduces, through the
other opening, freshly formed plates. When the operator has subjected the plates
at the one opening to the toughening process, he changes his place and proceeds in
the same manner with the plates situated at the other opening. The object of
using two moulds for each plate is as follows:
The mould should always have the temperature of the furnace. When there is
placed upon one of the moulds, a plate which has come from the press, it commu-
nicates its heat to the surface with which it is contact, while the other surface of
the plate is directly subjected to the action of the furnace heat. When this surface
has been heated to the required degree, the plate is turned over on to the other
mould so as to subject the other surface, which was in contact with the first mould,
to the furnace heat, while the mould on which the plate is now placed being at
the same temperature as the furnace, it in no way cools the surface of the plate
lying thereon. Thus, the plate is heated to a perfectly uniform temperature before
being subjected to the toughening process. The mould upon which the plate was
first placed having imparted some of its heat thereto, it requires to be subjected to
the furnace heat again before receiving a second plate. The moulds are manipulated
by means of a handle, the end of which is formed as a pair of tongs which are
caused to seize the handle'a on the moulds. When a mould has been used, the
workman removes his handle from it and cools it in water and then applies it to
another mould.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1, The herein described improved manufacture of plates and other articles of
toughened glass consisting of a body of opal glass coated on one or both surfaces
with toughened glass or crystal
2, The use, for toughening articles made of opal glass, of apparatus constructed
and operating substantially as herein described.