IMPROVEMENTS IN KILNS USED IN THE MANUFACTURE OF PLATE GLASS
Year: 1871

page_text: LETTERS PATENT to Thomas James Swinburne, of South Shields, in
the County of Durham, for the Invention of "IMPROVEMENTS IN
KILNS USED IN THE MANUFACTURE OF PLATE GLASS."
Scaled the 16th April 1872, and dated the 20th October 1871.
PROVISIONAL SPECIFICATION left by the said Thomas James Swin-
burne at the Office of the Commissioners of Patents, with his
Petition, on the 20th October 1871.
I, THOMAS JAMES SWINBURNE, of South Shields, in the County of
Durham, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN KILNS USED IN THE MANUFACTURE OF PLATE GLASS," to be as
follows:-
This Invention relates to the employment of fixed and immoveable
floors for the bottom of the annealing kilns used in the manufacture of
plate glass instead of the floors at present in use, which are constructed

page_text: of bricks embedded loosely in dry sand, and which by becoming dis-
arranged at every operation involve a daily expense in their
re-adjustment.
According to my Invention the fixed floors are constructed by first
laying a foundation of solid masonry of a sufficient thickness, say from
12 to 18 inches, upon which is laid a layer 4 or 5 inches thick of broken
pieces of tile, brick, or other suitable material mixed with a cement formed
of equal parts of ordinary masons' lime (without hair) and plaster of Paris.
This soon sets and forms a foundation for the upper bed. On this is
placed a layer of about half inch thick of a mixture of about two-
thirds of lime and one-third of plaster of Paris, and on this the bricks
are placed as close together as the natural inequalities of the brick itself
will allow. As this upper bed of half inch thick also sets after a short
time it is put down in small portions at a time, and the bricks placed
before the next portion is laid.
After the bricks are placed they are grated, i.c., there is poured into
their joints a mixture of plaster of Paris and water of the proper con-
sistence, and thus the bricks are firmly fixed. The kiln is then allowed
to stand for several days or a week to dry; fire is placed in the grate
rooms, and the kiln very gradually heated up during or 6 days, when,
after cooling and being swept out, and a thin sprinkling of coarse sand
spread over it, it is fit for use. A space of about 4 or 5 inches is left
vacant at the sides and ends of the kiln so that it has room for natural
expansion when the kiln is heated. These vacant places can be filled up
afterwards with sand.
Independently of the durable nature of the construction the floor itself
presents such a level surface to the under side of the glass which is
placed upon it that the glass is much smoother on that side; is con-
sequently ground with much less reduction of thickness and in a much
shorter time, and the glass can therefore be cast thinner with the same
resulting thickness after polishing.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas James Swinburne in the Great Scal Patent
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS.
JAMES SWINBURNE, of South Shields, in the County of Durham, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twentieth day of October, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas James Swinburne, Her special licence
that I, the said Thomas James Swinburne, my executors, administrators,
and assigns, or such others as I, the said Thomas James Swinburne, 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 KILNS USED IN THE MANUFACTURE OF PLATE GLASS," upon the
condition (amongst others) that I, the said Thomas James Swinburne,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describo
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 six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas James Swinburne, do hereby
declare the nature of my 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, that is to say :—
My Invention relates to the construction and employment of fixed
and immoveable floors for the bottoms of annealing kilns used in the
manufacture of plate glass instead of the floors at present in use, which

page_text: are constructed of bricks embedded loosely in sand, and which are liable
to become disarranged at every operation, and involving a daily expense
in their re-adjustment.
According to my Invention the earth or rubbish beneath the
bottom of the kiln is arranged at such a height from the level of the
floor of the glass house as to leave sufficient room for the upper con-
struction so that the uppermost level is of the height required. On this
earth previously made as level as possible two courses of common bricks
are laid with a cement composed of half lime and half plaster of Paris
or alabaster, care being taken to exclude all air in the building thereof.
On this lower bed is spread a layer of about half an inch thick of a
cement composed of about two-thirds of lime and one-third of plaster of
Paris; and on this the bricks forming the permanent upper floor are
placed edge up, and as close together as the natural inequalities of the
brick itself will allow. As this middle bed of half an inch of cement ]
quickly sets it is put down in small portions at a time, and the bricks
placed before the next portion is laid. The horizontal position of the
whole of the bricks with one another is secured by means of rules and
levels well known to the mason's art.
After the bricks are placed they are gruted in their joints with pure 2
plaster of Paris, which quickly sets and forms with the bricks a firm and
solid bed. In performing this last operation some of the plaster
necessarily flows into the surface of the bricks; this must be afterwards
cleaned off by a chisel or other suitable implement. The composition of
these cements may be varied; but I recommend the proportions given 2
above as having been found to answer.
The bricks I use for the upper
bed are those known by the name of "stock bricks," but this is not
essential. In laying the uppermost part of the floor care must be taken
to leave a space of four or five inches vacant all round between the stock
bricks and the walls of the kiln to allow for natural expansion when 3
the kiln is heated. These spaces can be filled up afterwards with sand.
I prefer making the floor in each kiln in two seperate beds or divisions,
for in this way the levels are more easily managed, but this is not
essential.
After the grating is finished the kiln is allowed to stand for several 3
days to dry, after which it is slowly heated up during five or six days. The
hottom is then firm and hard and the kiln fit for neo. Nothing further

page_text: is necessary save an occasional sprinkling of coarse sand to carry the
glass when pushed along the floor of the kiln.
Having now particularly ascertained and described the nature of my
said Invention, and the manner of performing it, I declare that I claim
as my Invention, constructing the kiln floors for annealing plate glass
of a fixed immoveable nature by means of bricks or blocks of other
material embedded in cement of some suitable composition, substantially
as described, so that no re-adjustment is necessary.
In witness whereof, I, the said Thomas James Swinburne, have
hereunto set my hand and scal, this Fifteenth day of April,
One thousand eight hundred and seventy-two.
THOS. J. SWINBURNE. (L.S.)