IMPROVEMENTS IN FURNACES.
Year: 1852

page_text: LETTERS PATENT to John Lee Stevens, of Kennington, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN
FURNACES.'
Sealed the 8th January 1853, and dated the 1st October 1852.
PROVISIONAL SPECIFICATION left by the said John Lee Stevens
at the Office of the Commissioners of Patents, with his Petition,
on the 1st October 1852.
I, JOHN LEE STEVENS, of Kennington, in the County of Surrey,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN FURNACES to be as follows:-
This Invention relates to double furnaces, where the product from
the fuel on one set of fire bars passes over or thro' the bright fire
on the other set of fire bars, which has heretofore been proposed to be
accomplished in various ways; and the improvements consist of apply-
ing the second fire bars above the first in such manner that the
bridge at the back end is common to the two sets of bars, and the
fuel may be fed into the two sets of bars thro' the one fire door.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Lee Stevens in the Great Seal Patent Office,
on the 30th March 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
JOHN LEE STEVENS, of Kennington, in the County of Surrey, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of October, in the year
of our Lord One thousand eight hundred and fifty-two, in the six-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Lee Stevens, Her special
licence that I, the said John Lee Stevens, my executors, administra-
tors, and assigns, or such others as I, the said John Lee Stevens,
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, excrcise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN FURNACES," upon the condition (amongst others) that
I, the said John Lec Stevens, by an instrument in writing under my
hand and scal, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be per-
formed, 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 John Lee Stevens, 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 relates to double furnaces, where the product from
the fuel on one set of fire bars passes over or through the bright fire
on the other set of fire bars, which has heretofore been proposed to be
accomplished in various ways; and the improvements consist of
applying the second fire bars above the first in such manner that the

page_text: bridge at the back end is common to the two sets of bars, and the fuel
may be fed on to the two sets of bars through the one fire door;
the object of which Invention is the more complete combustion of
the products of the fuel, as well as to prevent or lessen the formation
of smoke, which has heretofore been proposed to be accomplished in
various ways. And in order that my Invention may be most fully
understood, I will proceed to describe the same with reference to the
accompanying Drawings.
Figure 1, is a longitudinal, and Figure 2, is a transverse section of
a furnace, arranged or combined according to my Invention, applied
to a steam boiler. A, air passage; B, door-way to second or upper
furnace, and from which second furnace ignited fuel descends on to
the first set of fire bars; C, first set of fire bars nearest the floor;
D, second or upper set of fire bars, of one, two, or more ranges, accord-
ing to the length of the furnace; E, aperture by which fuel passes over
the second set of fire bars; F, plate, between which and the bridge
the products of the fuel on the first set of fire bars pass up and mix
In large
with the products from and over the other set of fire bars.
furnaces, or those used for marine or other purposes, wherein the fire is
kept up continuously for many hours, I protect the front of the plate
with fire bricks, carried by a bar about four inches above the ends of
the fire bars D. G, course of the current of air; H, bridge, serving
for both sets of fire bars; a, b, line of transverse section.
It will be seen by this description that whilst the first set of fire
bars C, is supplied with fuel over and through the second set of
fire bars D, the current of air G, accumulating heat and velocity in
a rapidly increasing ratio, in consequence of its passing between two
strata of fire, as well as between the plate F, and the bridge H, which
are naturally heated by the action of both fires, carries up with it the
products of the fire at C, and mixes the products of the fire from D,
therewith, whereby the most attainable combustion is effected, and
the formation of smoke most materially lessened, if not entirely
prevented.
I am aware that previous arrangements have been made of sets of
fire bars placed over each other, and that various other means have

page_text: been proposed for encreasing the combustion of fuel, and for consuming
or lessening the formation of smoke; I do not, therefore, claim such
arrangements or means otherwise than herein mentioned.
What I do claim is the mode herein described of combining and
arranging fire bars, and the manner of supplying the first set with fuel,
thereby causing the products of the fuel of the two furnaces to be
mixed and better consumed, as above explained.
In witness whereof, I, the said John Lee Stevens, have hereunto
set my hand and seal, this Thirtieth day of March, in the year
of our Lord One thousand eight hundred and fifty-three.
Witness,
B. GOBEY.
J. LEE STEVENS. (L.s.)