IMPROVEMENTS IN THE BRIDGES OF THE FURNACES OF STEAM BOILERS OR GENERATORS, OR OF OTHER FURNACES
Year: 1870

page_text: LETTERS PATENT to Isaac Bates, of Dukinfield, in the County of
Chester, Manager, and John Taylor, of the same Place, Engineer,
for the Invention of "IMPROVEMENTS IN THE BRIDGES OF THE FURNACES
OF STEAM BOILERS OR GENERATORS, OR OF OTHER FURNACES."
Sealed the 20th December 1870, and dated the 22nd June 1870.
PROVISIONAL SPECIFICATION left by the said Isaac Bates and
John Taylor at the Office of the Commissioners of Patents, with
their Petition, on the 22nd June 1870.
We, ISAAC BATES, of Dukinfield, in the County of Chester,
Manager, and JOHN TAYLOR, of the same Place, Engineer, do hereby
declare the nature of the said Invention for " IMPROVEMENTS IN THE
BRIDGES OF THE FURNACES OF STEAM BOILERS, OR GENERATORS, OR OF OTHER
FURNACES," to be as follows:-

page_text: some other descriptions of furnaces. The said bridges are situated at
the inner ends of the said furnaces, the flames or products of combustion
generated in the said furnaces passing over the said bridges as is well
understood, and the said bridges are most usually built up of fire-
bricks in the form of a solid wall having a flat or nearly flat top.
When constructing a bridge in manner according with our said In-
vention we make the top of the said bridge of the form of a segment of a
circle, the centre of the said circle by preference coinciding with the centre
of the furnace, supposing the said furnace to be of a circular form in cross
section so that the space for the passage of the products of combustion
may be of equal depth or thereabouts from end to end of the bridge.
In the body of the bridge we form an air channel extending as near
as may be to the length of the bridge, and communicating by means
of one or more openings with the space below the fire-bars, or with
the space outside of the furnace or boiler and on the upper surface of
the bridge, and on a portion of the surface which is towards the fire
are formed perforations or slots extending into the said channel, so
that there may be a flow of air through the said perforations or
slots.
We prefer to form the bridge principally of a single "fire-clay" lump, 1
the upper part of the said lump being curved as aforesaid, and having
formed therein an open channel extending downwards at each end, and
through the bottom of the said lump. The said lump is supported in
position on a metal plate, or is otherwise so supported that there may be
a free admission of air to the aforesaid air channel, and the bridge is 1
completed by covering the said channel and the upper part of the
"lump" with segmental bricks, which bricks are suitably grooved,
perforated, or slotted to permit the flow of air from the interior channel
as afore-mentioned. In place of making the body of the bridge of a
single fire-clay lump as aforesaid, the said bridge may be built up of
two or more lumps, each lump being so suitably formed as that when the
whole are fitted together the effect will be the same as when a single
lump formed as aforesaid is employed.
When preferred or required arrangements may be made to regulate
the flow of air into the aforesaid air channel. We prefer to make the
space over the bridge contracted as compared with the space usually

page_text: allowed. The air heated by flowing through the channels and passages
in the bridge and mixing with the products of combustion when the
said products are flowing through the space contracted as aforesaid,
causes a more perfect combustion of the gases generated in the furnace,
and thereby lessens the formation of smoke.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Isaac Bates and John Taylor in the Great Seal
Patent Office on the 22nd December 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ISAAC
BATES, of Dukinfield, in the County of Chester, Manager, and JOHN
TAYLOR, of the same Place, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-second day of June, in the
year of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Isaac Bates and John Taylor, Her special
license that we, the said Isaac Bates and John Taylor, our executors,
administrators, and assigns, or such others as we, the said Isaac Bates
and John Taylor, our 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 In-
vention for "IMPROVEMENTS IN THE BRIDGES OF THE FURNACES OF STEAM
BOILERS, OR GENERATORS, OR OF OTHER FURNACES," upon the condition
(amongst others) that we, tho said Isaac Bates and John Taylor, by
an instrument in writing under our, 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
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that we, the said Isaac Bates and John Taylor,
do hereby declare the nature of our said Invention and in what manner

page_text: whole are fitted together the effect will be the same as when a single
lump formed as aforesaid is employed.
When preferred or required arrangements may be made to regulate
the flow of air into the aforesaid air channel. We prefer to make
the space over the bridge contracted as compared with the space usually
allowed.
In order that our Invention may be well understood we have supplied
a Sheet of Drawings to accompany this Specification, the said Drawings
being made for the most part to a scale of about two inches to the foot,
and having similar letters marked upon corresponding parts in the various
Figures.
Referring in this place to the said Drawings, Fig. 1 represents a
longitudinal section of a steam boiler furnace; Fig. 2 is a cross section
of the same, and Fig. 3 is a horizontal section of a portion of the said
furnace shewing the upper surface of our improved bridge. The
remaining Figures illustrate modifications which may be made in the
said bridge. In the said Figures a is the shell of the boiler, b is the
shell of an internal flue of the said boiler, and c is the body of the
aforesaid fire-bridge, the said body of the fire-bridge is in this example
moulded to the required shape from fire-clay and afterwards burnt in
the usual manner. A channel d is formed in the said body and the said
channel is continued in a downward direction through the said body
as shewn by the dotted lines so that air may enter the said channel as
represented by the arrows in the lower parts of Figs. 1 and 2. The
upper portion of the said channel is covered by the fire-bricks e, c, which
are suitably cut or formed to fit together in the manner represented in
Fig. 2, or in such a manner as will cause the top of the bridge to bo
when completed of the curved form as or nearly as represented. The
said fire-bricks are perforated or are grooved so that perforations faro
formed by the juxtaposition of the said bricks, as shewn in the said
Drawings, and perforations are or may be formed in the body c of the
bridge, and the air entering the channel d as aforesaid is permitted to
flow through the said perforations and to mingle with the products of
combustion as they flow over the bridge. In the examples illustrated
the body c of the bridge does not extend to the full width of the furnace,
but bricks or blocks h, h, are fitted between the ends of the said body

page_text: and the shell of the furnace flue, this arrangement facilitating the
erection of the bridge and enabling bodies or bridges of the same
size to be fitted into furnaces varying in diameter to some extent.
In Figures 4, 5, and 6 the body of the said bridge is formed principally
of two lumps i and k, the said lumps being moulded from firc-clay and
afterwards burnt as in the case of the body c. In the lump shewn in
elevation in Fig. 6, an air channel is formed, and the portions extending
between the parts marked m³, are depressed so that when the other.
portion of the bridge i is connected with the said lump a slot or air
passage n is formed on each side of the centre of the bridge which said
slots are in communication with the air channel 7, so that air can flow
through the said channel and air slots or passages in the direction of the
arrows as in the case of the example first described.
Air passages
communicating with the air channel 1, and corresponding to the per-
forations in Fig. 2, may be formed in the lump k if desired.
preferred the air channels and slots or air passages may be formed
partly in each of the said lumps i and k.
If
Fig. 7 illustrates a method of building up a bridge composed of a
number of blocks moulded to such suitable forms that when the said
blocks are combined together to form a bridge the said bridge, will
contain the aforesaid air channels and air passages. We prefer however to
employ larger blocks moulded to the forms illustrated in the Figures
herein previously referred to, or to other suitable forms being modifications
of those illustrated in the said Figures. The air whilst flowing through
the aforesaid air channels and air passages, perforations, or slots becomes
heated to some extent and becoming mixed with the products of com-
bustion at the time that the said products are flowing through the
contracted space left between the upper surface of the bridge and the
crown of the furnace promotes the combustion of the gases generated
in the furnace, and thereby lessens the formation of smoke.
Having now described and illustrated the nature of our Invention and
methods of carrying the same into practical effect we would in con-
clusion have it to be understood that we desire to claim the method or
methods of constructing and forming the fire-bridges of the furnaces
of steam generators substantially as and for the purposes as herein-

page_text: before set forth and described and as illustrated in the accompanying
Drawings.
In witness whereof, we, the said Isaac Bates and John Taylor,
have hereunto set our hands and seals, this Twenty-first day of
December, in the year of our Lord One thousand eight hundred
and seventy.
Signed and scaled by the said
Isaac Bates and John Taylor,
in the presence of
EDWARD K. DUTTON,
Agent to the Patentecs,
3, Smithy Door,
Manchester.
ISAAC BATES. (L.S.)
JOHN TAYLOR. (L.S.)