A NEW PROCESS OF TEMPERING FLAT AND SHAPed Glass, AND FURNACES AND MACHINERY TO BE EMPLOYED THEREFOR
Year: 1874

page_text: LETTERS PATENT to François Barthelemy Alfred Royer de la Bastie,
of Boulevard de Strasbourg, No. 123, at Paris, France, for the
Invention of "A NEW PROCESS OF TEMPERING FLAT AND SHAPed Glass,
AND FURNACES AND MACHINERY TO BE EMPLOYED THEREFOR.
COMPLETE SPECIFICATION filed by the said François Barthelemy
Alfred Royer de la Bastic at the Office of the Commissioners of
Patents, with his Petition and Declaration, on the 12th August
1874, pursuant to the 9th Section of the Patent Law Amendment
Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANÇOIS
BARTHELEMY ALFRED ROYER DE LA BASTIE, of Boulevard de Strasbourg,
No. 123, at Paris (France), send greeting.
WHEREAS I am in possession of an Invention for "A NEW PROCESS
OF TEMPERING FLAT AND SHAPED GLASS, AND FURNACES AND MACHINERY TO BE
EMPLOYED THEREFOR," and have petitioned Her most Excellent Majesty
Queen Victoria to grant unto me, my exccutors, administrators, and

page_text: assigns, Her Royal Letters Patent_for the same, and have made solemn
Declaration that I am the true and first Inventor thereof.
NOW KNOW YE, that I, the said François Barthelemy Alfred Royer
de la Bastic, do hereby declare the nature of the said Invention to bo
as follows:
This Invention relates to a process of tempering glass and glass
articles so as to render them less fragile, and to the construction and
arrangement of furnaces and apparatus for effecting the said process.
As the fragility of glass results from the weakness of the cohesion of
its molecules it may be expected that by forcing-the-molecules_closer_
together, and rendering the mass more compact, the strength and
solidity of the material should be increased. I have found that this
cannot be effected by compression even when applied to the material in
a fluid or soft condition. I have therefore applied to glass a system of
tempèring such as is usually applied to steel, and I will now describo.]
the process and apparatus for this purpose.
1
Fused glass dropped into water becomes. greatly contracted, but being
shapeless only objects of curiosity can be produced in this way. The
sudden cooling in the water puts the glass into a state of unstable.
cquilibrium in its constitution, so that the least shock causes it to break
up, as in the case of Prince Rupert's drops. My object is to invert this
result, to diminish or even to remove the extreme fragility of glass by
tempering it by immersion in a liquid. In attaining this object two
essential conditions have to be determined:-First, the point at which
glass can be tempered without being put out of shape. I have found
this to bo when it is just at the heat where softness or mallcability
begins, the molecules being then capable of closing suddenly together,
condensing the material when it is plunged in a liquid at a considerably
lower temperature. Also glass, when it is thin, may be tempered at red
heat even before becoming soft; secondly, the liquid to be employed for
the immersion of the glass, being such as can be heated much higher
than water without boiling. For this purpose I find oils and grease,
wax, resin, and tar or pitch suitable. Having settled these conditions I
have devised the process or practical method of operating, and suitablo
furnaces and apparatus, which will hereafter be described.
In carrying out the process it is necessary that the glass to be
tempered should be raised to a very high temperature: the hotter it is
•

page_text: the less is the risk of breaking the glass, and the greater is the shrinkago
or condensation. Hence the advantage and often the necessity of
heating the glass to the point of softening, which is attended by the
difficulties that glass in the soft condition gets readily out of shape, so
that it must be plunged almost without touching it, and that in plunging
the hot glass into a heated combustible liquid the latter is apt to tako
fire, and cannot easily bo extinguished, so that, time and material aro
lost. These difficulties I have overcome by placing the tempering bath
in immediate communication with the heating oven, and covering it so
as to prevent access of air. The oven being charged with the articles to
bo tempered theso are pushed or caused to slide into the adjoining bath
without handling them, and the liquid of the bath having no supply of
external air is not liable to inflamo.
In order that the shape of the tempered articles may not be affected,
particularly for flat glass, the floor of the oven is made to cant so that
when the glass is heated on it it is turned to a sloping position, and the
glass slides into the bath along a surface therein arranged at the samo
slope as that of the oven floor. Small articles may be heated on the
edge of the bath, and immersed by a slight push. The clearness of tho
glass may be affected by the dust of the furnace flame, which is apt to
settle on the glass and chill its surface. I avoid this by heating tho
glass in a muffle, to which the flame has no access, being applied
externally. Moreover the shock of the fall of glass into the bath is
prevented by fixing therein a sheet of wiro gaużo or asbestos fabric, or
providing a bed of sand or other like material for the glass to fall on.
I will now describe furnaces and apparatus for carrying out in practice
the process which I have generally set forth above.
- Figs. A, A², A³; represent respectivȧly a front view, a vörtical section,
and a sectional plan of a simple form of the furnace and apparatus
embodying the general principles which I have mentioned.
The working oven a is heated by a furnace 1. The bottom of the
oven 2 and the slope to the bath 3 are; made in one piece of refractory.
material very smooth on the surface.. At the side of the oven a is a
preparatory oven e communicating by a passage 4 in the separating
wall 5. In the oven e the glass is partially heated before being placod

page_text: When the oven a is sufficiently heated the ash-pit and firc-doors 7 and
8 are closed, and rendered air-tight by luting, and the fire is maintained
by chips or small picces of fuel introduced by a hole 9 in the door 8.
The draught is then stopped by lowering the chimney cap 10, or closing
a damper. The vertical damper 11 is then raised so that the flame
passes by tho flue 12 to a second chimney 13, passing thus along the
slope 3 and heating it, and also opening communication from the oven «
to the bath b, which is filled with the prepared liquid. It is covered
from the external air by the lid 14, and within it is a basket c of finc
wire gauze hung from brackets. 15. A tube 10 contains a thermometer 17
to indicate the temperature, and by this tubo the contents of the bath
may be added to, or excess may overflow by the discharge 18. A plug 19
on the cover 14 may be removed to observo the interior without entirely
uncovering the bath. A fire-truck & charged with live fuel heats the
bath to the desired temperature. The glass is introduced into e by the
opening 20 in the outer wall 21, and thence it is moved through the
opening 4 on to the floor of a. The workman who watches the glass
through the eye hole 22 when he finds it at the proper heat pushes it by
an iron rod to the slope 3, whence it slides into the bath and is received
on the basket c. When the glass has cooled to the temperature of the
bath the lid 14 is removed, and the basket c is raised out of the bath
with the tempered glass.
Figs. B, B, and B³, represent respectively a front view, a vertical
section and a sectional plan of a furnace and apparatus moro particularly
applicable to the tempering of flat glass. The working oven a is heated
like that already described by the furnaco 1, and by its sido is a pre-
paratory oven communicating with it by an opening 2 in the separating
wall 3; a¹ is the chimney. When the oven a is sufficiently heated, tho
doors 4 and 5 are closed and luted, and the fire is maintained as before
by introducing small pieces of fuel through the hole 6 in the door 5, the
draught is then stopped by closing a chimney cap or damper. The
bath has hinged lids 7, and is provided with a tubo 9 and ther-
mometer 10. The bottom of the bath has a receptacle 12 to receive
such glass as may happen to break. A rocking table e rests on a
frame 25, which is fixed on a shaft 13 on which is fixed an external|
lever 11. An edge 15 at the end of the table retains a buffer 16 of wiro
gauze or other yielding material. Tho bath is heated by the firo C, tho
flame of which is made to circulate round and under the bath to the

page_text: chimney d, as indicated by the arrows. The sheets of glass to be
tempered are introduced by the opening 18 through the wall 18' into tho
preparatory oven, where they are gradually beated, and thence they are
pushed through 2 on to the oven floor, and finally on to the rocking
tablo 19, which is faced with very smooth refractory material and which
is in a level position at the time the glass is pushed on to it. When tho
workman who watches by the eye hole 20, finds that the glass is
sufficiently heated, he moves the lever 22 by its handle 22', and so cants
up the table 19 on its knife edges 24, bringing it in line with the sloping
table c. The glass sheet guided by the sides of the frame 25 slides down
the slope without shock or change of shape till its edge rests against the
buffer 16. The workman then by the lever 22 cants the table 19 back to
its horizontal position and pushes on to it another sheet to receive its
heat. The sheet already immersed is removed from the bath in tho
following manner:-The table e is raised by the lever 14 till a latch 26
is made by its counterweight 28, to catch under a stud 27 on the table.
The table being thus held the lever 14 is let go and is stopped in the
position indicated by the dotted lines 29, by a catch sliding into a notch
of the sector f, the catch rod being pushed by a spring placed between
the checks 31 along the three guides 32. In this position the buffer 10
and the hooked end of tho frame 15 are below the level 33 of the table c
(the frame moving back with the lover 14 while the table e remains
resting on the latch 20), so that the workman by means of a rako with-
draws the glass sheet gently into the compartment g, which is supported
on three cross bars 34. When this is done the latch 26 is withdrawn by
an exterior handle 35, and tho tablo e descends to and rests on its
frame 25. The workman then withdraws the sliding catch 30 by closing
together the checks 31, and lowers the lover 14 and the tablo e with its
frame till the end of the lever butts against an adjusting screw 36, tho
table being then in the inclined position for receiving another sheet. For
repairing the buffer 16, the cover 7 is opened, the lever 14 is raised till
its catch engages in the lowest notch of the arc f, the table e being then
in the position indicated by the dotted line 37, when the buffer is raised
above the liquid of the bath.
Figs. C, C, C³, and C', represent respectively a front viow, a vertical
section, a sectional plan, and a transverse section of one form of mufflo
furnace and apparatus for tempering glass, chiefly applicable to small

page_text: bricks 1. In the middle of the floor of the muffle is a holo 2 opening
over the bath b, and there are two inclined sido apertures 3 and 3¹
through the front wall 4. The flame of the fire 5 passes under tho
mulle, then up at one side and over and behind it to the chimney 7, as
indicated by the arrows. The bath 6 has a vertical passage 8 under the
holo 2 with a metal cono 19 to break the fall of the glass articles. Tho
upper end of the bath is covered by hinged lids 10; within the bath is
an endless chain working on square wheels 11 and 11', and having on its
links stages 9 fixed at such an angle as to lic horizontally. Thero is a
tube 14, with thermometer 15, and an overflow 16. The bath is heated
by a fire 17, the flame of which passes by a fluc governed by a damper 18,
circulates round the bath and issues by the chimney 7' as indicated by
the arrows. When the required heat is attained, the workman gently
pushes the articles into the muffle by the passage 3, watching them by an
eye hole in 3', and with a bar of iron or wood pushes them down the
hole 2, when they are received on one of the stages 9. When one stage
is charged the workman disengages a pawl latch 20 from a notch on an
external wheel 21, and by the winch 12 turns the chain wheels half
round, whereupon the latch 20 engages with another notch 22 on the
wheel 21. When all the stages 9 on the upper side of the chain havo
been charged, the cover 10 is opened and the articles are removed from
the stages 9 in succession.
Figs. D, D³, D³, represent respectively a front view, a longitudinal and
a transverso section of a double oven with rocking floor. The working
oven a is heated by the fire 1, the products of combustion heating also
the preparatory oven b. The draught is regulated by a damper 4 in the
chimney 3 or by a chimney cap. Part 5 of the floor of a, of smooth
refractory material, on a frame 6, is made to rock on knife edges 7 and 7'
by means of a pedal 8 pivotted at 9, and connected to the frame 6 by a
rod 10. The floor 5 is kept up level by a counterweight 11. The sheet 3
of glass is introduced into 6 by the opening 12, which is then closed by a
cover 13, and the sheet after preparatory heating in b is pushed into a
on to the rocking floor 5. When it is sufficiently heated the pedal 8 is
depressed, and thus the floor 5 is caused to slope downwards, as shewn in
Fig. D', so that the sheet slides down into a bath c made in sloping 3
compartments and mounted on a truck. When one of the compartments
is filled the truck is moved a little, so as to bring another compartment
in line with 5, and so on successively till all are filled, when the truck
and bath are withdrawn.

page_text: Eighth. The various arrangements of tempering baths and devices
connected therewith herein-before described and shewn on the Drawings.
In witness whereof, I, the said François Barthelemy Alfred Royer
do la Bastio, have hereunto set my hand and seal, this Tenth day
of August, in the year of our Lord One thousand eight hundred
and seventy-four.
Witness,
F. B. A. ROYER DE LA BASTIE. (L.S.)
ALBERT САПЕХ,
Civil Engineer,
of Boulevard Magenta, 32,
at Paris.