IMPROVEMENTS IN KILNS ANNEALING PLATE GLASS
Year: 1871

page_text: LETTERS PATENT to John Crossley, of St. Helen's, in the County
of Lancaster, for the Invention of "IMPROVEMENTS IN KILNS
ANNEALING PLATE GLASS."
FOR
Sealed the 30th April 1872, and dated the 29th November 1871.
PROVISIONAL SPECIFICATION left by the said John Crossley at
the Office of the Commissioners of Patents, with his Petition, on
the 29th November 1871.
I, JOHN CROSSLEY, of St. Helen's, in the County of Lancaster, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
KILNS FOR ANNEALING PLATE GLASS," to be as follows:-
This Invention has for its object improvements in kilns for annealing
plate glass. In place of heating annealing kilns by the combustion of
solid fuel in fire-places in connection with the kilns, as is now usual, I
employ gas in the following manner :-The kiln is constructed as is
usual with a bed of brickwork over which there is an arched roof, and

page_text: there are parallel flues passing longitudinally beneath the bed from
end to end. These flues I employ as gas and air flues. The gas,
which is generated at a distance, is admitted past a valve into the centre
flue, and by branches it is led to the four corners of the kiln bed, where it
rises into the chamber or body of the kiln by passages formed for the
purpose. In these passages there are regulating slides or valves. Close
to the four gas inlets are other similar inlets for the air necessary for its
combustion. This air before it enters the chamber or body of the kiln
circulates in the flues beneath the bed and is thus heated. The pro-
ducts of combustion pass out from the chamber or body of the kiln by
openings in the centre, one on either side, from which openings flues
pass downwards to a main flue in connection with a chimney.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Crossley in the Great Seal Patent Office on
the 28th May 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CROSSLEY, of St. Helen's, in the County of Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of November, 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 John Crossley, Her special license that
I, the said John Crossley, my executors, administrators, and assigns,
or such others as I, the said John Crossley, my executors, adminis-
trators, 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 FOR
ANNEALING PLATE GLASS," upon the condition (amongst others) that I,
the said John Crossley, 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

page_text: 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 John Crossley, 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, that is to say :-
This Invention has for its object improvements in kilns for annealing
plate glass. In place of heating annealing kilns by the combustion of
solid fuel in fire-places in connection with the kilns, as is now usual, I
employ gas in the following manner:-The kiln is constructed as is usual
with a bed of brickwork over which there is an arched roof, and there
are parallel flues passing longitudinally beneath the bed from end to end.
These flues I employ as gas and air flues. The gas which is generated
at a distance is admitted past a valve into one of the flues, which it
traverses and so becomes heated before it enters the body of the kiln.
The air for the combustion of the gas is similarly heated before entering
the body of the kiln by traversing another of the flues. In this way
the accumulation of heat beneath the bed of the kiln is to a great
extent prevented, and consequently the kiln is more readily cooled and
less heat is wasted than heretofore. When cooling the kiln air is allowed
to circulate in the flues beneath the bed as is now usual. Although it is
desirable that the whole of the gas and air employed in heating the kiln
should thus circulate beneath the bed and become heated, whilst at the
same time preventing an injurious accumulation of heat, nevertheless
in some cases it may be convenient, especially in adapting the Invention
to existing kilns, that only a portion of the gas and air should be caused
to traverse the flues beneath the bed, or the air alone may be thus heated
whilst the gas enters the kiln directly, or vice versa.
In order that my said Invention may be most fully understood and

page_text: on the line 1, 1, in Figure 1. a, a, is the bed of the kiln; b, b,
its side walls; and c, the covering arch over it; d¹, d², d³, d³, and ď³
are longitudinal flues beneath the bed. Extending across the front
of the kiln is the door for placing and removing the sheets of
glass. At the back of the kiln the gas fuel is admitted past a
regulating valve e into the centre flue d³, and it passes from this
flue by the branch flues d³ to the openings f, f, in the bed of
the kiln at its four corners. Each of the openings fis fitted with a
slide by which the width of the opening can be regulated and the
quantity of gas admitted by it adjusted; g, g, are underground passages
by which air can enter the flues d and d'; it passes from these into the
flues & and do, and then ascends into the body of the kiln by the four
openings h, h, in the bed in close proximity to the openings of by which
the gas is admitted; the heated gas thus meeting the heated air is burnt
within the kiln and the products of combustion pass away by two side
openings regulated by dampers into the flues i, i, which lead down into
an underground passage running beneath the series of kilns to a chimney.
Whilst the glass is being placed in the kiln the openings fand h at the
front of the bed are covered with iron gratings, which are afterwards
removed. When the kiln is cooling air is allowed to enter all the
flues d', d, d³, d, and do beneath the bed, and it passes over the bed to
the chimney, the rapidity of cooling being controlled by the dampers in
connection with the chimney flues i, or the air may be allowed to
circulate through the flues d', d², d³, d', and d³, without passing over the
bed of the kiln.
Figures 3 and 4 shew another arrangement applicable to kilns already
constructed with three flues under the bed. Figure 3 is a transverse
section and Figure 4 is a horizontal section taken on the line 2, 2,
Figure 3. a is the bed; b, the side walls; and c, the arch, as before;
ď³, d³, and ď³ are the flues beneath the bed, and e the regulating valve
past which the gas fuel enters the kiln. A portion of the gas enters the
flued by a passage e¹, and another portion rises by the duct k to an
opening c² immediately beneath the arch c, where it enters the body of
the kiln and is burnt. The air for the combustion of this portion of the
gas enters the flue ď³ at g, it passes to the front of the kiln and then
returns by the flue ď to the air duct 1, which also terminates in the
opening c¹, so that the gas in entering the kiln becomes thoroughly
mixed with the air and perfect combustion is insured. This form of

page_text: burner may with advantage be used in the kiln shewn in Figures 1 and 2
in place of that there represented. The gas from the flue & enters the
gas duct m, and is supplied with air by an air duct n communicating
with the glass house. These ducts terminate in a burner opening
immediately under the arch c and on one side of the kiln mouth. The
mouth in this kiln extends only partly across the kiln or it may extend
the entire width, and then the gas and air ducts m and n are placed in
the side wall. The products of combustion are drawn off from the kiln
at i either by an upward or downward flue; if the flue opening is in the
bed of the flue it should be covered with a grating whilst the glass is
being placed. The gas ducts k and and m and the flue i are provided with
dampers or regulating slides. It will be seen that in this arrangement
only a part of the gas and air for heating the kiln circulates beneath
the bed, which is a disadvantage of the arrangement, but it is a
convenient and ready way of adapting the Invention to existing kilns
with but three flues beneath the bed.
Having thus described the nature of my said Invention, and the
manner of performing the same, I would have it understood that what
I claim is, the construction of kilns for annealing plate glass in such
manner that the kiln may be heated by gas and air burnt together in the
body of the kiln, such gas and air or a part thereof being caused before
it enters the body of the kiln to traverse the flues beneath the bed which
also serve to accelerate the cooling of the kiln.
I also claim the construction of kilns for annealing plate glass, sub-
stantially as described.
In witness whereof, I, the said John Crossley, have hereunto
set my hand and seal, this Sixteenth day of May, in the year of
our Lord One thousand eight hundred and seventy-two.