Year: 1887

page_text: Date of Application, 10th Oct., 1887
Specification Accepted, 2nd Dec., 1887
We, CHARLES AMAND DURAND Engraver residing in Paris, rue Cardinal Lemoine
69, and ROBERT Philippe EngelmaNN, Printer residing in Paris rue de l'Abbaye 12,
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:
Our invention has for its object modifications in the processes for decorating glass
and in the material employed therein with a view to more rapid and economical
production.
We replace the furnaces actually in use for the burning of decorated glass which
admit only of pieces of very limited dimensions and which do not ensure sufficient
uniformity either in the heating or the cooling; by a furnace of new construction
adapted for continuous work and of large dimensions.
We also make certain modifications in the preparation of glass for decoration to
obtain on burning very varied and new effects by an economical method. The furnace
consists essentially of two cast iron or fire clay slabs, maintained at the middle of their
length by means of jets of gas at a temperature sufficient for the fusion of enamel.
Between these slabs the panels or sheets of painted or enamelled glass are passed in a
slow and continuous manner, being propelled either by means of two rotating cylinders
pushing the carriers on which the sheets of glass are placed or they are drawn forward
by means of endless chains passing over two drums at the entrance and back of the
furnace. By their passage through this furnace the sheets of glass are gradually
heated to the fusion point of the enamel whilst they pass from the entrance towards
the middle of the furnace, and then are gradually cooled as they proceed towards the
exit.
The distinctive character of this method of burning the sheets of painted or enamelled
glass appears sufficiently in the drawings annexed.
+
Figures 1 and 2 are longitudinal and transverse sections of the furnace. Figure 3
is also a longitudinal section and shows a modification.
In the furnace represented in Figures 1 and 2 the cast iron or fire clay slabs A
upporting the painted or enamelled sheets B B are advanced by the aid of a drawing
or propelling mechanism. The sheets B B pass between two other cast iron or fire
brick slabs CC maintained sufficiently hot for the fusion of enamel. The furnace thus
מ

page_text: presents three spaces a b c formed by the slabs CC, D D which are sustained by fire
brick masonry as is shown in Figure 2. The middle space 6 serves as a hot chamber
in which the sheets to be heated pass successively, whilst the top and bottom spaces a c
serve to admit air to the flame heating the whole length of the furnace to temperatures
proportional to the distances from the gas burners E E. It results that when a sheet
enters cold at d it is gradually heated as it approaches the middle e which is the hottest
part, then after being submitted to the effect of this high temperature, it passes on
and cools gradually and by the time it arrives at fit is cold. The glass is warmed up,
burnt and cooled more or less rapidly according to the rapidity of the movement which
is communicated to the slabs on which it rests. Two means can be employed to move
the sheets through the furnace traction or propulsion.
In Figure 1 the sheets are made to move by means of two cylinders F F touching
the cast iron slabs A A, so that each carrier introduced between the two cylinders F F
may be pushed forwards driving before it the carriers which have been previously
introduced.
By this arrangement the cylinders F F push the carriers A A bearing the sheets BB
onwards towards the exit f where they are removed successively. The carriers A A
can be fitted with rollers to facilitate their movement along the furnace. Traction
can also be employed with the aid of an endless chain H (Figure 3) turning upon
two toothed drums I I placed at the ends of the furnace; the carriers A A are placed
on the chains and the movement draws them successively from the entrance d to the
exit f. In this case the carriers A. A can be done away with and the sheets B B can
be placed directly on the chain H.
In our experiments we have succeeded in burning a surface of painted or enamelled
panes measuring two and a half metres in length by eighteen centimetres in breadth
in one hour, at a cost of two cubic metres of gas, obtaining at the same time
products of a perfection hitherto unknown. This we have done in a furnace only four
metres long.
We do not limit ourselves to the arrangements described and we reserve the right
of introducing the gas in any convenient form and manner for furnace work and in
point of view to the result to obtain. We reserve ourselves also the right of placing
simultaneously several slides superposing them in the same furnace in the conditions
substantially described for effecting the simultaneous baking of several panes.
The top and bottom parts of the furnace may contain drying spaces K K heated by
the waste heat of the furnace; these we employ for storing the sheets, in order to
protect the glass from a too rapid cooling.
As respects the preparation of the glass for burning, our improvements consist in
combining the application of vitrifiable colours and with engraving with fluoric acid
upon superficially coloured glass; this enables us to obtain commercially by the aid
of the process known as transfer printing colorations which are nearly impossible by
existing processes. We proceed as follows:
We commence coloring upon the glass by the aid of an engraving. To do this we
print on a gummed paper a suitable drawing with a varnish capable of resisting the
action of fluoric acid. We sprinkle this freshly printed drawing with rosin and fix
the design with water on a sheet of glass coloured superficially.
Then we heat the glass, the rosin is melted and adheres to the glass and we only
have to take off the paper by the aid of water.
The glass is then in a suitable condition to be engraved by fluoric acid; the printed
parts being protected retain the original color whilst all the rest of the surface is eaten
into by the acid.
We can obtain different values of the same coloration by successive biting, or we
employ glass coated on both sides and thus have several colours.
The glass having thus obtained the principal coloration or that which cannot be
obtained otherwise we have only to apply the pattern and the remaining coloration
registering exactly with the first.
We always employ the chromolithographic process and take care that the register
is quite exact with the engraved design; print the enamel and vitrifiable colours

page_text: lithographically on a sized piece of paper, such as that which is employed in the process
known as transfer printing.
We apply these colours either by rollers or in powder superposing them according
to the effect we wish to obtain. When the design is complete we transfer it to the
glass by the ordinary method of transfer printing.
It is necessary that it should adhere perfectly and after letting it dry, we have only
to lift the paper with the aid of water.
The glass thus prepared can be brought to the furnace as if it had been hand
painted. The combination of these operations permit the production economically
with very rich and diverse effects of large surfaces of glass without join or the usual
lead framings.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what we
claim is :-
1. The process of burning painted or enamelled glass by causing it to travel
between two plates heated at the middle sufficiently to fuse the enamel the
temperature of the glass being gradually raised as it passes from the entrance to
the heated point and then gradually lowered as it approaches the exit substantially as
described.
2. The process of manufacturing decorated glass by removing portions of the
superficially coloured surface by fluoric acid and then ornamenting the parts so
treated by means of enamels or vitrifiable colours substantially as described.
3. The processes and apparatus substantially as described and shown in the
drawings.
A