IMPROVEMENTS IN FURNACES
Year: 1858

page_text: PROVISIONAL SPECIFICATION left by the said Thomas Rowell at the
Office of the Commissioners of Patents, with his Petition, on the 9th
January 1858.
.I, THOMAS. ROWELL, of Sunderland, Engineer, do hereby declare the nature
5 of the Invention for "IMPROVEMENTS IN FURNACES," to be as follows:-
This Invention has for its object improvements in furnaces. For these
purposes the two sides of a furnace are constructed of hollow castings of iron,
which are connected at their front ends with a hollow dead plate, the under
surface of which has an opening into it for the passage of air. These castings
> are connected transversely of the furnace by a hollow chamber within the
bridge of the furnace, and such chamber by a central passage communicates
with a transverse hollow casting which is beyond the bridge, the ends of
which communicate with air passages. on either side of the furnace, and
external to the hollow sides above mentioned. At the front end of each of
these passages is an opening into the furnace, which can be closed gradually
by a door or valve; hence, when these doors or valves at the front ends of the
air passages are open or partly open, air will enter from below into the front
hollow dead plate, pass laterally into the hollow sides of the furnace, thence'
into the chamber at their ends; thence into the hollow casting beyond the
bridge, thence through the air passages into the front of the furnace, the air

page_text: becoming highly heated before it enters the furnace. In order that the air may
be admitted for a time only after feeding the fire with fresh fuel, and that the
air so admitted into the furnace may be gradually reduced after such feeding,
the doors or valves at the ends of the side air passages are arranged to be
opened by the act of opening of the fire door, by suitable mechanism com-
municating between the fire door of the furnace and the air doors or valves,
and such air doors or valves are not closed by the closing of the fire door,
but are arranged to be acted on by means of an apparatus which is well
known, which is regulated to act by means of air or other fluid passing
through a small passage, and according to the time which the fluid takes in
passing, so is the time within which the air doors or valves are closed. In
some cases, particularly in tubular boilers, the hollow casting above described
as being placed beyond the bridge is dispensed with, and (in place of the
heated air coming directly into the front of the furnace, there is a perforated
plate or partition across the front of the furnace, with an opening through
which the fuel is thrown; such opening is provided with doors, and such doors
are closed after the feeding of the fire has been accomplished. By this
arrangement the air coming from the side passages is divided into numerous
streams by the perforated plate or partition.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Rowell in the Great Seal Patent Office on the
9th July 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
ROWELL, of Sunderland, Engineer, send greeting.
WHEREAS Her most Excellent. Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of January; in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Rowell, Her special licence that I, the said Thomas
Rowell, my executors, administrators; and assigns, or such others as I, the
said Thomas Rowell, 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 "In-
PROVEMENTS IN FURNACES," upon the condition (amongst others) that I, the

page_text: said Thomas Rowell, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 I, the said Thomas Rowell, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, 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 furnaces. For these
purposes the two sides of a furnace are constructed of hollow castings of iron,
which are connected at their front ends with a hollow dead plate, the under
surface of which has an opening into it for the passage of air. These castings
are connected transversely of the furnace by a hollow chamber within the
bridge of the furnace, and such chamber by a central passage communicates
with a transverse hollow casting which is beyond the bridge, the ends of
which communicate with air passages on either side of the furnace, and
external to the hollow sides above mentioned. At the front end of each of
these passages is an opening into the furnace, which can be closed gradually
by a door or valve; hence, when these doors or valves at the front ends of the
air passages are open or partly open, air will enter from below into the front
hollow dead plate, pass laterally into the hollow sides of the furnace, thence
into the chamber at their ends, thence into the hollow casting beyond the
bridge, thence. through the air passages into the front of the furnace, the air
becoming highly heated before it enters the furnace. In order that the air
may be admitted for a time only after feeding the fire with fresh fuel, and that
the air so admitted into the furnace may be gradually reduced after such
feeding, the doors or valves at the ends of the side air passages are arranged
to be opened. by the act of opening of the fire door, by suitable mechanism
communicating between the fire door of the furnace and the air doors or
valves, and such air doors or valves are not closed by the closing of the fire
door, but are arranged to be acted on by means of an apparatus which is
well known, which is regulated to act by means of air or other fluid passing
through a small passage, and according to the time which the fluid takes in
passing, so is the time within which the air doors or valves are closed.
. And in order that my said Invention may be most fully understood and
readily carried into effect, I will proceed to describe the Drawings hereunto
annexed.

page_text: Figure 1 is a vertical section, Figure 2 a transverse section, Figure 3 a
horizontal section, and Figure 4 a front view of a steam boiler furnace con-
structed according to my Invention. a, a, are hollow castings bedded into the
side walls of the furnace, and communicating at the front ends with the hollow:
dead plate b, which has an opening underneath it at b', for the admission of
air; c is a chamber within the bridge of the furnace, and into this chamber.
the air enters after it has passed through the dead plate 6 and the side
castings a, a. The fire bars d, d, I sometimes make hollow, as is shown in
the Drawings, and in this case they also are connected with the chamber c, and
supply heated air to it; e is a central passage by which the heated 'air passes
to the transverse hollow casting placed beyond the bridge, and connected at
its ends with the air passages g, g, formed in the brickwork' on either side of
the furnace, and external to the hollow castings a, a, at the front of the
furnace; at 91, 9', are openings into the furnace, which are furnished with.
doors or valves h, h. When the fire door is opened to feed the furnace, these
doors or valves are opened by the fork i on the fire door acting on an enlargo-
ment on the rod j, and moving it longitudinally in its guides, and the
connecting links k, k, communicate the motion to the doors or valves. The
rodj also actuates a bent lever 1, to the end of which the rod of a cupped
leather piston working within the cylinder m is attached, and this piston is:
thus drawn down towards the bottom of the cylinder, the water (with which
the cylinder is filled) passing the leather of the piston freely when it is
moving in this direction. When the fire door is again closed, the weight n
tends to draw the piston again to the top of the cylinder, but this it cannot do.
immediately, for the top and bottom of the cylinder are only connected
together by a very small passage, and as the water gradually passes under the
piston through this passage the piston ascends, and the doors or valves h, h,
are again closed. Thus provision is made for a free supply of heated air
immediately that the furnace has been supplied with fuel, and this supply is.
gradually reduced in quantity as the fire burns brighter, until ultimately it is
cut off altogether till more fuel is required.
In constructing the furnaces of tubular boilers I sometimes adopt the
following arrangement:-The hollow casting f beyond the bridge is dispensed
with, and the air passes through the fire bars, and it may be also through
passages on each side of the furnace to the chamber in the bridge, and from
this chamber it returns by a passage under the fire bars to the dead plate in
front, and escapes through a perforated plate into the furnace, the passage of:

page_text: the air being controlled by valves as already described. This arrangement
may be slightly modified, as is shown at Figures 5, 6, 7, and 8, which illustrate
the method which I prefer to employ when constructing the furnaces of
tubular boilers. Figure 5 is a vertical section, Figure 6 is a transverse section,
Figure 7 is a horizontal section, and Figure 8 is a front view of a furnace so
constructed; the air is supplied to the chamber c by hollow fire bars d, and
escapes from it directly to the furnace by the passages c', c'; air also enters
through an opening in the dead plate b, and passes by passages furnished with
valves, as already described, behind the perforated plate o, and escapes through
it into the furnace. In this arrangement, as in that before described, in
which a perforated plate o is employed, it is furnished with a door, which is
open to supply fuel to the furnace, and is then closed, so that the heated air
may be compelled to pass through the perforations in the plate; Figures 9,
10, 11, and 12 show a cylindrical boiler with a furnace arranged according to
my Invention, but differing in some respects from the construction shown at
Figures 1, 2, 3, and 4, the hollow casting f beyond the bridge being dispensed
with, and some other minor changes made. a, a, are hollow castings bedded
in the walls of the furnace as before, but in this case they are protected from
the direct action of the fire by a lining of fire-brick; the air in its passage
from the dead plate 6 to the hollow castings a, a, passes by doors or valves
h, h, which regulate its flow. The chamber c within the bridge is divided into
two parts, and the air from one of the side castings a passes through one part,
and the air from the other through the other part; thus the whole of the air is
compelled to pass from end to end of the bridge; it afterwards enters the air
passages 9, 9, and from these it escapes by the openings g¹, g', into the
furnace.
In witness whereof, I, the said Thomas Rowell, have hereunto set my
hand and seal, this Eight day of July, in the year of our Lord One
thousand eight hundred and fifty-eight.
Witness,
WILLIAM D. BURLINSON,
of Sunderland.
THOMAS ROWELL. (L.S.)