ROVEMENTS IN HARDENING, TEMPERING, AND PRESSING GLASS, AND APPARATUS THEREFOR
Year: 1875

page_text: "
In the Matter of Letters Patent granted to FREDERICK SIEMENS, of
Dresden, in the German Empire, for the Invention of IMPROVEMENTS
IN HARDENING, TEMPERING, AND PRESSING GLASS, AND APPARATUS
THEREFOR,” bearing date the 3rd May, 1875, No. 1637.
DISCLAIMER AND MEMORANDUM OF ALTERATION as proposed to be
entered by the said Frederick Siemens pursuant to the Statutes in that case
made and provided.
WHEREAS Her Majesty Queen Victoria, by Her Letters Patent, under the
Great Seal of the United Kingdom of Great Britain and Ireland, bearing date at
Westminster the Third day of May, 1875, No. 1637, in the Thirty-eighth year of
Her reign, did give and grant unto the said Frederick Siemens, his executors,
administrators, and assigns, the sole privilege for the term of fourteen years thence
next ensuing of making, using, exercising, and vending within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and the Isle of Man, the said
Invention of "IMPROVEMENTS IN HARDENING, TEMPERING, AND PRESSING GLASS,
AND APPARATUS THEREFOR."
And whereas in pursuance of a proviso in the said Letters Patent contained,
I the said Frederick Siemens, did within six calendar months next after the
date of the said Letters Patent cause a Specification or instrument in writing
under my hand and seal purporting to describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, to be duly filed in
the Great Seal Patent Office:
And whereas since the filing of the said Specification, I, the said Frederick
Siemens, have ascertained that considerable practical difficulties attend certain
applications of the process therein described, and I desire to confine my claim in
respect of the said Invention to that which can be usefully practised by the use of
apparatus such as is described in the said Specification, as illustrated by the
Drawings annexed thereto.
I therefore disclaim and alter the said Specification in manner following, that is
to say:-
"
Referring to the Queen's Printers copy of the said Specification, second edition,
at page 3, line 8, I omit the words "and moulding;" at page 3, lines 18 and 19,
I omit, "after having been partially or even completely shaped and; at page 3,
line 37, I omit, "after having been partially or wholly shaped; at page 3, line 39,
I omit the passage beginning with the words "and as many," and ending at
*[Price 4d1

page_text: line 45 with the words "hardening process; " at page 3, line 48, I omit the passage
beginning with “
although," and ending at page 4, line. 3, with "previously shaped;"
at page 4, line 35, after the words "above referred to," I insert "nor do I claim
the simultaneous moulding and tempering of glass articles, nor the tempering by
the process above described of glass articles other than those that are of uniform
or nearly uniform thickness;" at page 4, line 36, I omit the word "first; " at
page 4, line 36, after the word "hard pressed" I insert the word " tempered." I
omit the second and third claims, that is to say, in page 4, lines 39 to 45 inclusive.
And the said Specification when so disclaimed, altered, and amended will read
as follows.
My Invention relates to means of hardening and tempering glass according to
the known process of heating it, and then suddenly cooling it, and also to the
combination there with of means for pressing glass articles so as to give greater
density and preserve their form while they are subjected to the hardening and
tempering process.
The hardening and tempering process, as it is described in the Specification of a
Patent granted to F. B. A. Royer de la Bastie on the 12th August, 1874, No. 2783,
consists in beating the glass articles to a high temperature and then plunging
at
them while hot into a liquid of a lower temperature.
According to my Invention when the glass articles are such as are usually
moulded I effect their hardening and tempering at the same time with their pressing,
so as to produce a hard and pressed glass by the use of moulds of metal or other
suitable material in which the glass articles while they are in a highly heated
condition are squeezed, the moulds having the effect of giving the necessary cooling
without baving recourse to a liquid bath.
The material employed for such moulds will depend upon the nature and
thickness of the glass to be operated on; in cases where the cooling has to be
effected rapidly metals of good conducting power, such as copper, are to be preferred,
and in cases where the cooling has to be effected more gradually moulds of
earthenware or other materials that are bad conductors of heat may be used.
Again, in cases where the glass articles operated upon vary in thickness the con-
ductivity of different parts of the mould is varied accordingly, either by making
thicker those parts of the mould which come next to the thickest parts of the glass
so as to absorb a greater amount of heat, or by making those parts of a better
conducting material than the parts next the thin portions of the glass. The moulds
will also have to be maintained at a certain temperature varying according as the
nature of the glass to be operated upon requires that they should be cooled to a
greater or less degree. It will generally be found sufficient to employ cast iron
moulds that are maintained at the temperature of boiling or warm water, and
earthenware moulds that are kept quite cool.
The glass articles are placed in a heating oven in order to be raised to the
requisite degree of heat for being subjected to the above described pressing and
cooling process. The heating ovens employed may be of any suitable known
construction, but it is preferable to use ovens heated by gaseous fuel in order to
prevent the purity of the glass from being impaired.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents a transverse, and Fig. 2 a longitudinal section of a regenerative
gas muffle oven suitable for heating the glass articles that are to be hard pressed
according to my Invention; Fig. 3 is a front view of this oven, and Figs. 4 and 5
are sectional plans on the lines Y, Y, Z, Z, of Fig. 1 respectively. The muffle A is
heated both under its floor and over its crown by the flame of the gas and air from
the one pair of regenerators B1, B2, and the heated products of combustion pass off

page_text: through the other pair of regenerators B³, B, till the first pair being sufficiently
cooled and the second pair sufficiently heated the direction of the currents is
reversed for alternate working in the usual manner. The muffle A being completely
closed in the glass articles heated in it are protected from dust and other impurities,
such as in an open oven are apt to settle on the softened glass and damage its
surface. Fig. 6 is a side view; Fig. 7 an end view, and Fig. 8 a plan of a pair of
pressing moulds and carriage such as may be conveninently employed in the hard
pressing process. The lower mould C placed on the truck D receives the heated
glass from the oven and the truck in then run under the upper mould E, which is
let down upon it, being loaded when necessary to give the desired pressure. The
moulds shewn in Figs. 6 and 7 are suited to flat glass plates for glass articles
of other shapes; the moulds are made of suitable form, as shewn in Fig. 9, where c
is a hollow or concave lower mould with a glass plate p resting on it by its edges,
and e is a corresponding convex upper mould, which being lowered on the glass ?
presses it down into the lower mould, the glass being thus at the same time pressed
and hardened by the cooling influence of the moulds.
The temperature of the moulds may be kept at the required point by charging
them with liquid, as shewn with respect to the upper moulds in Figs. 6, 7, and 9.
Usually water serves for this purpose, the temperature of its boiling point being
well suited to give the required hardening.
Having thus described the nature of my Invention and in what manner the
same is to be performed, I hereby declare that I make no claim to the hardening
or tempering of glass by plunging it into a liquid bath at a lower temperature,
as described in the Specification to De la Bastie's Patent above referred to, nor do
I claim the simultaneous moulding and tempering of glass articles, nor the
tempering by the process above described of glass articles other than those that are
of uniform or nearly uniform thickness, but I claim,―
The process substantially as herein described for producing hard pressed tempered
glass by subjecting heated glass articles to pressure in moulds at a lower
temperature, where the glass is simultaneously compressed and hardened.
In witness whereof I the said Frederick Siemens, have hereunto set my
hand and seal, this Thirtieth day of November, in the year of our Lord
One thousand eight hundred and seventy five.
FREDERICK SIEMENS. (L.S.)
I hereby grant my fiat, giving leave to the above named Frederick Siemens
to file in the Office of the Commissioners of Patents for Inventions, with the
Specification to which the same relates, the above written Disclaimer and
Memorandum of Alteration.

page_text: AND PRESSING GLASS AND APPARATUS THEREFOR.'
"
.
PROVISIONAL SPECIFICATION left by the said Frederick Siemens at
the Office of the Commissioners of Patents, with his Petition, on
the 3rd May 1875.
I, FREDERICK SIEMENS, of Dresden, in the German Empire, do
hereby declare the nature of the said Invention for "Improvements in
HARDENING, TEMPERING, AND PRESSING GLASS AND APPARATUS THEREFOR," to be
as follows:
My Invention relates to means of hardening and tempering glass
according to the known process of heating it and then suddenly cooling
it, and also to the combination therewith of means for pressing and
moulding glass articles, so as to give greater density and preserve their
form while they are subjected to the hardening and tempering process.

page_text: The hardening and tempering process as it is usually conducted
consists in heating the glass articles to a high temperature, and then
plunging them while hot into a liquid at a lower temperature; but as
at the high temperature the glass is soft and yielding it is difficult to
preserve the form of the glass articles when subjected for a lengthened
time to such high temperature. To avoid this evil I construct the
heating oven in two compartments, the one heated only to that degree
at which glass though softened will retain its shape, and the other
heated to the higher temperature which the glass should have when it
is plunged; and I arrange the liquid bath at the bottom of this hotter
compartment. I heat the glass in the first compartment, and then
passing it through the second compartment on its way to the bath.
I thus impart to it during its passage the additional heat required.
The mode of passing the glass through the hot compartment is
necessarily varied according to the nature of the articles operated on.
When they are cylindrical or round in form, like lamp glasses or globes,
I allow them to roll down an incline from the first compartment,
through the second, and thence into the bath. When they are not of
such a shape as will permit them to roll I place the first compartment
above the second and allow the articles to drop through a hole in the
partition which separates the two compartments, so that they fall
through the hot compartment down into the bath. Or I place the two
compartments side by side with the partition between them not reaching
to the top. And I shoot each article obliquely upwards over the top
of the partition, so that it falls through the hot compartment into the
bath. This shooting may be effected by a spring let loose by a trigger,
or by means of a piston worked by steam or compressed air.
When the glass articles are such as are usually moulded I effect their
hardening and tempering at the same time with their pressing, so as to
produce a hard and pressed glass by the use of moulds of metal or other
suitable material, in which the glass articles after having been partially
or even completely shaped, and while they are in a highly heated con-
dition, are squeezed, the moulds having the effect of giving the necessary
cooling without having recourse to a liquid bath.
The material employed for such moulds will depend upon the nature
and thickness of the glass to be operated upon; in cases where the
cooling has to be effected rapidly metals of good conducting power,

page_text: such as copper, are to be preferred, and in cases where the cooling has
to be effected more gradually moulds of earthenware or other materials
that are bad conductors of heat may be used.
Again, in cases where the glass articles operated upon vary in
thickness the conductivity of different parts of the mould is varied
accordingly, either by making thicker those parts of the mould which
come next to the thickest parts of the glass, so as to absorb a greater
amount of heat, or by making those parts of a better conducting
material than the parts next the thin portions of the glass. The moulds
will also have to be maintained at a certain temperature, varying
according as the nature of the glass to be operated upon requires that
they should be cooled to a greater or less degree. It will generally be
found sufficient to employ cast-iron moulds that are maintained at the
temperature of boiling or warm water, and earthenware moulds that
are kept quite cool.
The glass articles after having been partially or wholly shaped are then
placed in a heating oven in order to be raised to the requisite degree of
heat for being subjected to the above described pressing and cooling
process, and as many glass articles when subjected for a length of time
to a high temperature, such as would be necessary in the present case,
are apt to get out of shape I prefer in such cases to enclose them before
placing them in the heating oven in a casing or shell of platinum, which
supports the glass and prevents it from getting out of shape while in the
heating oven, the glass article with the platinum shell upon it being
then place in the mould for the pressing and hardening process. The
heating ovens employed may be of any suitable known construction,
but it is preferable to use ovens heated by gaseous fuel in order to
prevent the purity of the glass from being impaired.
Although it is in most cases preferable to heat the glass articles in
such heating ovens before subjecting them to the pressing and cooling
process, as above described, yet the partially formed glass article may
in some cases be conveyed direct from the glass melting furnace on the
glass blower's pipe into the pressing and cooling moulds; or the liquid
glass may even be conveyed direct into the pressing and cooling moulds
without having been previously shaped.

page_text: SPECIFICATION filed in pursuance of the conditions of the Letters
Patent, and of an Order of the Lord Chancellor, by the said
Frederick Siemens in the Great Seal Patent Office on the 3rd
December 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
SIEMENS, of Dresden, in the German Empire, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of May, in the year of our
Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Frederick Siemens, Her special
license that I, the said Frederick Siemens, my executors, admini-
trators, and assigns, or such others as I, the said Frederick Siemens,
my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN HARDENING, TEMPERING, AND PRESSING GLASS AND APPARATUS
THEREFOR, upon the condition (amongst others) that I, the said
Frederick Siemens, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within seven calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Siemens, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, reference being had to the accom-
panying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say :-
"
My Invention relates to, means of hardening and tempering glass
according to the known process of heating it and then suddenly cooling
it, and also to the combination therewith of means for pressing and
moulding glass articles, so as to give greater density and preserve their
form while they are subjected to the hardening and tempering process.

page_text: The hardening and tempering process, as it is described in the Speci-
fication of a Patent granted to F. B. A. Royer de la Bastic, on the 12th
August 1874, No. 2783, consists in heating the glass articles to a high
temperature, and then plunging them while hot into a liquid at a lower
temperature.
According to my Invention when the glass articles are such as are
usually moulded I effect their hardening and tempering at the same
time with their pressing, so as to produce a hard and pressed glass by
the use of moulds of metal or other suitable material, in which the glass
articles; after having been partially or even completely shaped, and
while they are in a highly heated condition, are squeezed, the moulds
having the effect of giving the necessary cooling without having recourse
to a liquid bath.
The material employed for such moulds will depend upon the nature
and thickness of the glass to be operated on; in cases where the cooling
has to be effected rapidly, metals of good conducting power, such as
copper, are to be preferred, and in cases where the cooling has to be
effected more gradually moulds of carthenware or other materials that
are bad conductors of heat may be used.
Again, in cases where the glass articles operated upon vary in
thickness the conductivity of different parts of the mould is varied
accordingly, either, by making thicker those parts of the mould which
come next to the thickest parts of the glass, so as to absorb a greater
amount of heat, or by making those parts of a better conducting material
than the parts next the thin portions of the glass. The moulds will
also have to be maintained at a certain temperature, varying according
as the nature of the glass to be operated upon requires that they should
be cooled to a greater or less degree. It will generally be found
sufficient to employ cast-iron moulds that are maintained at the
temperature of boiling or warm water, and earthenware moulds that
are kept quite cool.
The glass articles after having been partially or wholly shaped are
placed in a heating oven in order to be raised to the requisite degree of
heat for being subjected to the above described pressing and cooling
process, and as many glass articles when subjected for a length of time
to a high temperature, such as would be necessary in the present case,
are apt to get out of shape, I prefer in such cases to enclose them before

page_text: placing them in the heating oven in a casing or shell of platinum, which
supports the glass and prevents it from getting out of shape while in
the heating oven, the glass article with the platinum shell upon it being
then placed in the mould for the pressing and hardening process. The
heating ovens employed may be of any suitable known construction,
but it is preferable to use ovens heated by gaseous fuel in order to
prevent the purity of the glass from being impaired.
Although it is in most cases preferable to heat the glass articles in
such heating ovens before subjecting them to the pressing and cooling
process, as above described, yet the partially formed glass article may
in some cases be conveyed direct from the glass melting furnace on the
glass blower's pipe into the pressing and cooling moulds; or the liquid
glass may even be conveyed direct into the pressing and cooling moulds
without having been previously shaned
Fig. 1 represents a transverse, and Fig. 2 a longitudinal section of a
regenerative gas muffle oven suitable for heating the glass articles that
are to be hard pressed according to my Invention.
Fig. 3 is a front view of this oven; and Figs. 4 and 5 are sectional
plans on the lines Y, Y, Z, Z, of Fig. 1 respectively.
The muffle A is heated both under its floor and over its crown by the
flame of the gas and air from the one pair of regenerators B¹, B², and
the heated products of combustion pass off through the other pair of
regenerators B³, B', till the first pair being sufficiently cooled, and the
second pair sufficiently heated the direction of the currents is reversed
for alternate working in the usual manner. The muffle A being com-
pletely closed in the glass articles heated in it are protected from dust
and other impurities, such as in an open oven are apt to settle on the
softened glass and damage its surface.
Fig. 6 is a side view; Fig. 7, an end view; and Fig. 8, a plan of a pair
of pressing moulds and carriage, such as may be conveniently employed
in the hard pressing process. The lower mould C placed on the truck D
receives the heated glass from the oven, and the truck is then run under
the upper mould E, which is let down upon it, being loaded when
necessary to give the desired pressure. The moulds shewn in Figs.
6 and 7 are suited to flat glass plates; for glass articles of other shapes

page_text: the moulds are made of suitable form, as shewn in Fig. 9, where c is a
hollow or concave lower mould, with a glass plate p resting on it by its
edges, and e is a corresponding convex upper mould, which being
lowered on the glass p presses it down into the lower mould, the glass
being thus at the same time pressed and hardened by the cooling
influence of the moulds.
The temperature of the moulds may be kept at the required point by
charging them with liquid, as shewn with respect to the upper moulds
in Figs. 6, 7, and 9. Usually water serves for this purpose, the tem-
perature of its boiling point being well suited for giving the required
hardening.
Having thus described the nature of my Invention, and in what
manner the same is to be performed, I hereby declare that I make no
claim to the hardening or tempering of glass by plunging it when heated
into a liquid bath at a lower temperature, as described in the Speci-
fication to De la Bastie's Patent, above referred to, but I claim,―
First. The process, substantially as herein described, for producing
hard pressed glass by subjecting heated glass articles to pressure in
moulds at a lower temperature, whereby the glass is simultaneously
compressed and hardened.
Second. In the process referred to in the preceding claim the use of
moulds having parts made of various thickness or of materials having
various degrees of conductivity, so as to effect the uniform cooling
of various parts of the glass articles treated, substantially as herein
described.
Third. The use of platinum moulds to maintain glass articles in shape
when they are heated for the purpose of being compressed and hardened
by the process above referred to.
In witness whereof, I, the said Frederick Siemens, have hereunto
set my hand and seal, this Thirtieth day of November, in the
year of our Lord One thousand eight hundred and seventy-five.
FREDERICK SIEMENS. (L.S.)